Development of Noonee Chairless Chair

Development Of Noonee Chair less Chair

2017-18

DEVELOPMENT OF NOONEE CHAIRLESS CHAIR

ABSTRACT

Abstract: It’s an innovative and forward -thinking concept, the ability to sit anywhere and

everywhere with the aid of a chairless chair. It’s like a chair that isn’t there, but magically appears whenever you need it. It’s called the chairless chair and you wear it on your legs like exoskeleton , when it’s not activated , you can walk normally or even run. Like a chair that is

now there. Standing for hours or end causes a lot of distress to lower limbs, but most works get very few breaks and chairs are rarely provided , because they take up too much space. So the best idea was to strap an unobtrusive chair directly to yourself. So it was decided to have this innovative concept in reality, to help workers who work for hours on production line in standing position and tired. Today the world is now going to be compact. For suitability to the world, things are also going to be made of compact and smaller in size. Now the battle is also done between machines instead of man to man. To win this war and to thought regarding another parallel motive force to the automobile, we have thought of manufacturing "Chairless Chair" through the mission of the project. The exoskeleton based pneumatics support is basically a “chair” which is clothing like

an exoskeleton, allowing users to walk or move at certain speed with the device while they work. This chair helps to rest the leg muscle when you are working for a long time. This new and innovative chair helps to comfort to thighs and back. It keeps back straight and reduces pain in the back as well as thighs. The overall weight of this exoskeleton pneumatic chair is only one kg so it doesn't burden on a wearer. Index Words: Chairless Chair, Exoskeleton, Ergonomics

Dept Of Mechanical Engineering

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INTRODUCTION

Exoskeletons are defined as standalone anthropomorphic active mechanical devices that are “worn” by an operator and work in concert with the operators movements.

Exoskeletons are mainly used to increase performance of able-bodied wearer. (e.g. for military applications), and to help disabled people to retrieve some motion abilities.(such exoskeletons are called “active orthoses” in the medical field). As we know, the normal motor capability of

legs is crucial and important for human-beings daily life. Legs, however, are apt to be injured in accident. And the Rehabilitation is essential for the patients to recover after leg operation. Additionally, diseases, stoke for instance, can also result in the loss of leg function [1]. In order to regain the motor capability, the leg rehabilitation is a fundamental therapeutic approach. Basically Exoskeletons are of two types: a) Active Exoskeletons b) Passive Exoskeletons Active exoskeletons: They are powered by external sources like a motor, battery powered etc. They work along with the passive exoskeletons to help in its functioning. Passive exoskeletons: These are not powered by external power sources but work on the basis of mechanical linkages, pneumatic and hydraulic mechanisms, spring controlled devices etc. Since active exoskeletons pose a restriction to the amount of external energy that can be supplied in terms of quantity, quality and time we have focused purely on passive type of exoskeletons. Passive elements are implemented in the exoskeleton to either store or dissipate energy with the objective of reducing the residual energy that the human would have to expend for locomotion. It is very difficult to stand and work for overall shift in the company by a worker. This will reduce the efficiency of the worker. The solution to this problem is to have a portable device which has an ergonomic design, low cost exoskeletons. In this work a mechanical ergonomics device that is designed around the shape and function of the human body, with segments and joints corresponding to those of the person it is externally coupled with. It functions as a chair whenever it is needed and is coined as Chair less Chair. Worker in industrial can wear it on legs like an exoskeleton. It locks into place and you can sit down on it. The device never touches the ground, which makes it easier to wear: a belt secures it to the hips and it has straps that wrap around the thighs. These are specially designed and part of the mechanism, but an alternate version works with any footwear and touches the ground only when in a stationary position. The user just moves into the desired pose. It will fit closely to lower part of the body as an external Dept Of Mechanical Engineering

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body part on which maximum body bod y forces act upon. It is a cost effective product and any error in design may fail the structure which creates loss. So, these forces should be carefully analyzed during the design of structure. The best way to predict these forces during pre-manufacturing stage is to make an analysis on the structure with the help of software. This helps in estimating the stresses induced on the structure which is one of the most important criteria for evaluation of the model. The chair is of compelling artifact and simplicity, in spite of the fact that for a long time and undoubtedly for a great many years it was an article of state and pride as opposed to an article of customary utilization. The chest, the bench and the stool were until then the ordinary seats used in regular living, what's more, the quantity of chairs which have made due from a before date is exceedingly restricted; a large portion of ecclesiastical or seigneurial beginning. Our knowledge into the chair of remote relic is gotten altogether from landmarks, model and artworks. Many types of chairs seen around such as : 

A seat without a back or o r arm rests is a stool.

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When bump up, a bar stool.

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Arm chair is having arms.

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A recliner is a chair with folding action and reclining footrest.

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A forever settled seat in a train or theater is a seat.

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A chair with wheels is called a wheelchair.

When riding, it is a saddle.

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A seat for more than one individual is a sofa, couch, seat, settee or loveseat.


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PROBLEM STATEMENT

Sitting is a position that adds anxiety to the structures in the spine. To abstain from creating or intensifying back issues, it is vital to have an ergonomic seat that backings the lower back and inspires great stance. In today's general public, numerous will be sitting throughout the day either in office situations or working machines. Although sitting requires less physical exertion than standing or strolling, regardless it puts a considerable measure of weight on the lumbar zone. Joined impacts of an inactive way of life and work that obliges sitting can prompt numerous wellbeing issues. The choice of a suitable seat is a basic venture in anticipating wellbeing issues for individuals working in a sitting position. Sitting is a position that adds stress to the structures in the spine. To abstain from creating or An all around outlined seat permits the client to sit in an adjusted position. Purchasing an ergonomic seat is a decent starting however it must be consolidated with a legitimate stance to augment the advantages. The world is getting compact day by day & we know the most useful devices are compact in size. If you are working in a restaurant kitchen, factory you will know you are tired for many hours. In manufacturing company keeping employee healthy has been major problem and challenges for companies around the world hence it needs to manufacture the "chair less chair" or "exoskeleton based pneumatics support". It is not possible to carry a stool around with you at every time that's why we are introducing this exoskeleton based pneumatic support. This exoskeleton based support helps to stand for long times. It improves walking and running economy and reduces the joint in pain or increases the strength in joint. It transfer load directly to ground. The exoskeleton is powerful mechanical devices. In pneumatic support, a pneumatic cylinder is used to engage and hold the person body it only wrap around thighs, so it reduces fatigue and increases the productivity. It’s an innovative and forward-thinking concept the ability to sit anywhere and every-where with

the aid of a chairless chair. The concept was first conceived two years ago by Keith Gunura, cofounder and CEO of noonee, and since then the company has developed its Chairless Chair and entered talks with a number of leading manufacturers. Designed for static and dynamic industrial market applications, the Chairless Chair aims to increase user’s health, comfort, and Dept Of Mechanical Engineering

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productivity. It’s like a chair that isn’t there, but magically appears whenever you need it. It’s called the Chairless Chair and you wear it on your legs like an exoskeleton: when it’s not

activated, you can walk normally or even run. Like a chair that is now there.Standing for hours on end causes a lot of distress to lower limbs, but most workers get very few breaks and chairs are rarely provided, because they take up too much space. So we thought that the best idea was to strap an unobtrusive chair directly to you. The device never touches the ground, which makes it easier to wear, a belt secures it to the hips and it has straps that wrap around the thighs. A variable damper engages and supports the bodyweight, which is directed towards the heels of the shoes. These are specially designed and part of the mechanism, but an alternate version works with any footwear and touches the ground only when in a stationary position.The ’chairless chair’, which Audi has further developed together with a Swiss start up company, is an

exoskeleton that is worn on the back of the legs. It is fastened with belts to the hips, knees and ankles. Two leather covered surfaces support the buttocks and thighs while two struts made of carbon fiber reinforced plastic (CFRP) adapt to the contours con tours of the leg. In this world technology is increasing day today life. As we move forward the technology is progressing and it is becoming compact for easy to carry carr y it with us. Tendency of human hu man whose current job requires them to stand for long hours is decreasing. This new and modernized “chair”

will ease the aches in the thighs and back. For this purpose we have design a lower body exoskeleton. It is ergonomics device that is designed around the shape and function of the human body, with segments and joints corresponding to those of the person it is externally coupled with. Its like a chair that isn‟t there ,but magically appears whenever you need it. In industrial, it is known as the chairless chair and worker in industrial can wear it on legs like an exoskeleton. Although lower body exoskeletons already exist on the market, they still have shortcomings that prevent widespread use among the general public. Our method of achieving our goal consists of splitting up into smaller groups; allowing us to complete work more efficiently. The objectives of this project are to study , analyse, and develop a new mechanism that assist the human locomotion, to learn in details about how the lower body exoskeleton works and understand the concepts involved. The concepts of this simple chair is when it activities; you can walk normally or even run.


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CLASSIFICATIONS OF EXOSKELETONS

PROBLEM STATEMENT

The major problem faced by elderly people are :-  Inability to sit , stand perform transfers and to walk

need for personal assistance at home

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risk losing independence

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reduce quality of

life  financial problems to employees careers Factor Consideration In A Project: 1. Compatibility with project and plan. 2. Availability of needed material and skill for research. 3. Move out away a critical technical problem. 4. Go back of financial expected. 5. Cost and availability of capital required for investment. 6. Estimate of costs of development, production, and marketing. 7. Growth prospects for the future.


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FACTOR CONSIDERATION IN A PROJECT:

1) Compatibility with project and plan. 2) Availability of needed material and skill for research. 3) Move out away a critical technical problem. 4) Go back of financial expected. 5) Cost and availability of capital required for investment. 6) Estimate of costs of development, production, and marketing. 7) Growth prospects for the future.

OBJECTIVE :

The objective of our project is to enable the worker to have the ability to move around with absolute ease, with the use of a lower body exoskeleton .i.e. chairless chair. The project is so simple with the help of chairless chair worker can move freely here and there without any stresses and fatigue or pain.To develop a portable device capable of providing ankle joint mechanical assistance during walking without using external power from on board actuators. The device we set out to build should be light weight, portable and user friendly. The device should not hamper the normal gait cycle of an individual but should only enhance it. Our goal was to provide all of the benefits of an actively powered exoskeleton but in a portable framework without motors or an external energy source to provide an ease in the gait cycle. We hypothesize that a passive wearable device using parallel elastic elements during the walking cycle is capable of recycling a significant portion of the ankle joint mechanical work and could reduce the metabolic cost of walking. We set out to develop a passive, „energy-neutral‟ system with the

following key design objectives.


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Through design research, to investigate the claimed ergonomic benefits of the Chairless Chair to determine if it might have a part to play in improving assembly associates’ short-

term fatigue and long-term musculo-skeletal well-being. 

To identify how the introduction of the Chairless Chair might potentially mitigate on-going costs due to improved assembly worker retention and reduced worker absences through chronic musculo-skeletal ill-health.

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To identify potentially suitable assembly stations that might see enhanced production efficiencies (through reduced process times) were the Chairless Chair to be introduced as an ergonomic aid.

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To suggest a pilot implementation strategy that would serve to overcome resistance from sceptical assembly associates.


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LITERATURE REVIEW

In this paper we are very much interested in the wearable devices which help in increasing the efficiency of the human and decrease the rate of fatigue of human during work. The device discussed here is the passive device. This device is known as Chairless Chair which helps the wearer to work effectively at any location in a sitting posture. H. Zurina and A. Fatinhas worked on the Design and Development of Lower Body Exoskeleton. In his paper an attempt has been made to evaluate the possibility of using the Chairless chair that will help in increasing the energy efficiency and offer weight support when the user feels tired rather than continuously taking on the weight[2]. Other than that, in term of ergonomics, and the objectives to give comfort to user has achieved by give choices to user to choose their comfort degree level from 45° to 90°. Apart from the benefit of his experiment it can be conclude that his design still confront with some problems that need to fix in future so that the objective to give an ergonomic chair to user can be achieved. The experiment testing has been conducted for our prototype to our group member with weight of 80kg and height around 170cm. From the result of experiment testing, it can be observed that for height and weight, the Chair less chair doesn’t give any effect in lack or over measure in its height dimension. It suit the user which prove that this chair can be wear by people from any height range. He tester were required to use the chair while do some work, it was observed that, he had difficulties in changing the degree level Aditya Bhalerao and Sandesh Kamblehave worked on Pneu portable chair for employees to seat while working. By referring to human seating and walking characteristic a leg mechanism has been conceived with as kinematic structure whose mechanical design can be used by employees as an wearable exoskeleton. As per the Specified Design parameters the body can suitably carry around the 100Kg of Human Body weight. In the later part to reduce the cost, Oil was also brought in the weight sustaining mechanism thus providing better results. These type of device with ergonomical background can be easily upgraded with the use of more advanced technologies and culminating various facilities into one body and be constantly modified .A basic idea of how a exoskeleton using Pneumatic or Hydraulic Cylinder can be used to reduce the fatigue by using simple kinematic mechanisms. In this Particular Machine due to certain Dept Of Mechanical Engineering

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restrictions not much advancement has been made and it is similar to a tailor made clothing which is just suitable for one single person and may not fit properly to other user. Although as mentioned with advanced techniques it can be made more generalized for more no, of people to use it[6]. It has several major applications in real time scenario where it can be worn in the crowded trains or public places with space constrains. Also it can be worn by Traffic Police who work for long hours and are exposed to fatigue for a prolong period of time Cyril Varghese and Vedaksha Joshi has worked on the Exoskeleton Based Hydraulic Support was successfully fabricated and it was found to be suitably safe [3]. Under fluctuating load during walking as well as under Dead Load when the user sits/rests on it. (Tested the Extra Large Size Variant for a user weighting 116 kgs for a span of 43 days) The entire cost of making the EBHS is Rs 8540 ($ 126.84) thereby making is very economical for the general public as well as for Industrial use and also for the Military. When in full scale production , the EBHS will be available in three sizes , From 5ft to 5‟5” : Regular Size , From 5‟5” to 6ft : Large Size ,From 6ft to 6‟5” : Extra Large Size . The EBHS being extremely light in weight causes very little

hindrance while walking and the user can easily get used to it.


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Noone has worked on the lower limb exoskeletons called Chair less Chair. This product is also known as a "mechatronic device" worn on the legs, which allows the user to walk or run when not activated [4]. Once the device is activated, it uses a portable variable damper to engage and hold the person's body weight, relieving the stress on leg muscles and joints. The user just needs to move into the desired pose, this activates the device. This device is based on research from the Bio-Inspired Robotics laboratory at ETH Zurich. A belt secures the wearable to the hips and its straps wrap around the thigh. Since it is the chair that can carry the person's body weight, the stress on leg muscles and joints is relieved. The device runs for about 24 hours on a single 6V battery and an aluminum and carbon fiber frame keeps the overall weight of the Chair less Chair at just two kilograms, so it doesn't burden the wearer with too much excess weight. Productionline trials started in Germany with BMW in September and with Audi later in the year 2015. The user can sit comfort in the places where the people are densely crowded using this device. This device is totally controlled by a mechatronic system.


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ERGONOMICS

Ergonomics is the examination of the collaboration in the middle of individuals and machines and the components that influence the communication. Its object is to enhance the execution of frameworks by enhancing human machine connection. This could be conceivable by 'delineating in' an unrivaled interface or by 'arranging out' components in the work environment, in the errand or in the association of work that corrupt human – machine execution. Frameworks can be improved by • Outlining the client interface to make it more good with the undertaking and the client. This

makes it less requesting to use and more impervious to lapses that individuals are known to make. • Changing the workplace to make it secure and more suitable for the task. • Changing the undertaking to make it more immaculate with customer characteristics. • Changing the way work is created to suit people's mental and social needs.


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ANTHROPOMETRY

Changing the way work is formed to suit people's mental and social needs the word "anthropometry" implies estimation of the human body. It is gotten from the Greek words "anthropos" (man) and "metron" (measure). data are used as a piece of ergonomics to demonstrate the physical estimations of workspaces, equipment, furniture and clothing to ensure that physical mismatches between the measurements of gear and items and the relating client measurements are evaded. Designing for a solitary individual demands his dimensional variations to be well accommodated. When designing for mass utilization and for unknown individuals, one of the most relevant statistical interpretations & considerations is the percentile estimation of the gathered information taken from a specific population group. Many types of chairs are discovered now-a-days and their design are different from one another. To build a chair many objects are required for example: 

Material

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Chair be located ( kitchen/ office)

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How often will chair be used (3*day/ all day)

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Will be people be doing anything else as they sit in the chair ( eating/ reading)

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Will this chair get dirty often (yes/ hopefully not)

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Who will use the chair

To design a chair anthropometric data are most important feature. Anthropometry is the measurement and the art of application that establishes the physical geometry, mass properties and quality abilities of human body. Anthropometry data helps designer to determine the size and shape of perfect chair. Anthropometry data for most male and female body measurements overlap so the designer work to sizes. The Chairless Chair then locks into that configuration, directing their weight down to the heels of their shoes, to which it is attached it also attaches to the thighs via straps, and to the waist using a belt. There are as many different types of chairs as there are types of people. It is an object that is Dept Of Mechanical Engineering

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available to most everyone. In its different embodiments it can be humble or regal, made of traditional wood or high-tech polymers, simple in con-cept or highly charged with meaning. Fundamentally, the requirements for a chair are few. It is essentially a horizontal surface at a logical distance from the ground meant to support the human body while sitting. A vertical surface is provided for back support. A. Links Mild Steel links selected as per the ergonomics guidelines such that the links between the waists to knee is of 380 mm and the knee to ankle is 420 mm which is most common for Indian people. The Mild Steel square bar available in the market of mostly two size of thickness one is 1 mm and another is 3 mm thick. So as per market availability and safety we select the Mild Steel links of cross section = 30*30*1 .Square hollow section of Mild Steel is selected, as sectional modulus of Square section is more B. General purpose steel bars for machining, suitable for lightly stressed components including studs ,bolts, gears, shafts, link ,rounds ,clips etc. Often specified where weldability is requirement can be case harden to improve wear resistance .Available in bright rounds, squares and flats , and hot rolled round.mild steel is readily available in abundant quantity and is less costly, it has good resistance to dust, fumes, it has rugged construction C. Shoe Link Shoe Link is used for attachment of our shoes with chairless chair. It facilitated for easily walking along with chairless chair. It is fixed with the help of nut bolt with lower link. D. C. Stopper It is the most important part of our project. This Part gives stability to whole project. It is made up of mild steel. E. Tie Belt Belt is used for strapping of exoskeleton to human body. Belt will be taken as standard material available in market to wrap the model as waist and thigh

The Chairless Chair (and similar) exoskeletons are based on prior research going back many decades to allow people to sit in nearly any situation. Chairless Chairs type devices have been recorded being used in factories, surgical rooms, and public transportation. It is designed to reduce fatigue from standing in place for too long.


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CHAIRLESS CHAIR HISTORY

What is the shape of the ever growing exoskeleton industry in 2016 and what does the term mean in the first place? In 2016, exoskeleton industry is growing at an unprecedented rate. Every month one or two research groups will spinoff into a startup or a small exoskeleton company will become renowned enough to become visible internationally. The older and more established exoskeleton companies are continuously searching for new applications and releasing brand new or revised wearables. With this growth spurt, it is becoming useful to organize and define the exoskeleton market. In this article we will explore: 

The term, “exoskeleton industry” is widely used, but what does it mean?

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Where does the exoskeleton industry fit?

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What does it look like in 2016?

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How did the terminology come about?

Defining “exoskeleton industry”

The term “exoskeleton” is currently the dominant word to describe all manners of wearables that

provide some nature of physical interaction with the person wearing it. The exoskeleton could provide a physical boost, hinder the user on purpose or support the weight of an object that the user would otherwise have to support themselves.


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Exoskeleton and Exoskeleton Industry are umbrella terms.

Exoskeletons and the exoskeleton industry fall under wearables. However, wearables is a very general term that includes all manners of electronics and gadgets (example Fitbit) that do not have any physical interplay with the user. Exoskeletons also fall under robotics, but there are many passive exoskeletons that rely purely on biomechanics and have no electronics. Wearable robotics includes all powered orthotics and prosthetics (powered replacement legs and arms) but it again leaves out the passive devices and combines non-exoskeleton devices. Exoskeletons also fall under ergonomics, but again the term is too broad to be sufficiently descriptive.


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The exoskeleton industry in 2016 stands at the overlap of biomechatronics and biomechanics.

A term that was really popular for a few years to describe the exoskeleton industry was biomechatronics.

Biomechatronics is the merger of biology, mechanical and electrical

engineering. However, this term too fell out of favor as more and more passive exoskeletons were introduced. As it stands, exoskeleton manufacturing now lies in the overlapping area between biology and mechanics (biomechanics). Powered exoskeletons also include electronics and lie at the crossing of all three disciplines. What does the exoskeleton industry look like in 2016?


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In 2016 the exoskeleton industry can be divided into four categories or subfields: Industrial, Medical, Military and Commercial. The four subfields can be further subdivided by device type and application.

Wearable robotics designed to be used in an industrial setting is the fastest growing field of exoskeleton development. Exoskeletons for work and industry can be used at construction sites, dry-docks, factories, warehouses and even surgical rooms. In a recent presentation by the Wearable Robotics Association, Dr. Joseph Hitt described exoskeletons for manufacturing and


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construction as the “low hanging fruit” of the exoskeleton market. Exoskeletons for work and

industry can be separated into 6 categories: tool holding, chairless chairs, back support, power gloves, full body powered suits, and additional / supernumerary robotics.

Medical Exoskeletons:

Wearable robotics designed to be used as a rehabilitation or augmentation medical devices is the second oldest field of exoskeleton development. The first working medical exoskeleton was created in 1972 by the Mihajlo Pupin Institute in Belgrade, Yugoslavia (modern-day Serbia). A major breakthrough was the recognition that exoskeletons can perfectly recreate the same motion repeatedly thousands of times. This translates to patients being able to perform more exercise repetitions in the same amount of time with higher consistency. Additionally, it is now being demonstrated that medical exoskeletons can provide much more useful rehabilitation. Newer exoskeleton software prevents users from “riding along” during exercises. Patients also have to

hit correct stances and will not receive assistance until they themselves initiate the exercise motion. The medical exoskeleton subfield can be broken down into six parts: stationary lower body, stationary upper body for hand and fingers rehabilitation, stationary lower body rehabilitation and augmentation, and mobile upper body exoskeletons


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Wearable robotics for the military is the most dynamic subset of the exoskeleton industry. Military exoskeletons are being tested by the U.S., China, Canada, South Korea, Great Britain, Russia and Australia, and these are just the projects that the public is aware of. Many other military exoskeleton projects remain secret. There is still enough information in the public domain to see how much military exoskeletons have changed over the last 10 years and the new direction exo developers have taken. Military exoskeletons currently fit into five categories: stationary, energy scavenging, lower body, full body and passive

Commercial Exoskeletons:

Civilian and commercial exoskeletons comprise the smallest subfield of the exoskeleton industry, but they also hold the greatest commercial promise. The main potential for commercial exoskeletons is their possibility to be accepted as motorized transportation devices that require minimum infrastructure.

However, this is still in the distant future.

For now,

commercial exoskeletons are limited in scope to augmentation, hiking, and sports injury prevention.

Commercial exoskeletons are exos that can be used outside of a medical

rehabilitation context and are not for work & industry

Types And Classifications of Exoskeletons


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Exoskeleton systems can be divided into many different categories, types or classifications based on a series of questions: 1. What body parts are actuated or powered by the wearable device? 

full body

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upper extremities: arms and torso 

further broken down into specific areas: some exoskeletons can concentrate on the wrist and fingers, while others focus on the shoulder and elbow joints

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lower extremities: legs 

further broken down into: hip, knee, or ankle only, hip-knee, hip-ankle, knee-ankle or hip-knee-ankle. The motion can also be in more than one plane of rotation.

2. Is it powered? 

powered exoskeletons use batteries or electric cable connections to run sensors

and actuators 

static exoskeletons: the actuators need to be turned on at all times in order for the device to maintain its shape.

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dynamic exoskeletons: actuators do not need to be turned on at all times and the device can be many times more energy efficient. This type of exoskeletons are further differentiated by what they are designed to do.

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passive exoskeletons do not have any electrical power source and can be used

for: 

weight re-distribution: springs and locking mechanisms divert the weight of an object around the user and into the ground

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energy capture: ankle spring-clutch exoskeletons have been shown to improve walking efficiency, while spring-dynamo knee exoskeletons can be used to charge a battery.

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dampening: some spring or spring-damper passive exoskeletons have been designed as shock absorbers (high-speed skiing – Ski Mojo) or vibration reducers (small high-speed boat – Marine Mojo)


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locking: some passive exoskeletons are designed to be unobtrusive until they are locked into place, allowing the user to sit or crouch in the same position for a prolonged period of time.

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pseudo-passive exoskeletons have batteries, sensors, and other electronics, but

they are not used to provide actuation. 

The best example of a pseudo-passive exoskeleton is the C-Brace by Ottobock , which uses its electronics to control a variable damper in the

knee. The C-Brace alternatively unlocks, slows down the swing of the leg and locks depending on the position of the leg in the gait cycle as determined by the integrated sensors. 

hybrid-exoskeletons are wearables that have all of the controllers and sensors of

a powered exoskeleton but use FES (functional electrical stimulation) of the muscles as actuators. 3. Is it mobile? 

fixed: the device is tethered, attached to a wall, a bracket or suspended from the air by a fixed hook and harness

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supported: the exoskeleton is attached to an overhead rail, is supported by a moving frame or in some cases, supported by an adjacent wheeled robot. These configurations allow for the heavy motors, controllers and batteries to be externally supported while still granting mobility to exoskeleton wearer.

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mobile: the user and exoskeleton can move around freely.

4. How is it controlled (user-machine-interface)? 

joystick: reserved for exoskeletons that provide 100% of the energy for motion needed by the wearer.

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buttons or control panels: the exoskeleton is placed in different pre-programmed modes. The control surface does not have to be on the exoskeleton, previous designs have them on a wrist strap, integrated into walking aids such as crutches or held by a supervisor adjacent to the user.

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mind-controlled: using an electrode skull cap


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sensors: current exoskeletons designs can have as many as 40 different integrated sensors that monitor rotation, torque, tilt, pressure and can capture nerve signals in the arms and legs

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no control: some passive exoskeletons have no control buttons or switches.

5. How is it built? 

rigid materials such as metals or carbon fiber.

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flexible materials in the entire construction (soft exoskeleton or exosuit).

6. Origin? 

home built (DIY) – some of the biggest companies today started out in garages

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research labs (academia)

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commercial companies (industry)

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governments – currently only the Chinese government is actively developing an exoskeleton. All other governments may provide grants, but are looking to buy a working model.


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FABRICATION PROCESS


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FABRICATION OF BASIC COMPONENTS

Fabrication of basic components includes the operations that undergoes the development of the project. The following are the operations that are involved in the progress of the project.


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FABRICATION PROCESSES INVOLVED

CUTTING

The raw material cut into the required dimensions using a grinding wheel cutter. Metal cutting is done by a relative motion between the work and piece and the hard edge cutting tool, which is multi point cutting tool.

In the context of machining, a cutting tool or cutter is any tool that is used to remove material from the workpiece by means of shear deformation. Cutting may be accomplished by single point or multipoint tools. Single-point tools are used in turning, shaping, planing and similar operations, and remove material by means of one cutting edge. Milling and drilling tools are often multipoint tools. Grinding tools are also multipoint tools. Each grain of abrasive functions as a microscopic single-point cutting edge (although of high negative rake angle), and shears a tiny chip. Cutting tools must be made of a material harder than the material which is to be cut, and the tool must be able to withstand the heat generated in the metal-cutting process. Also, the tool must have a specific geometry, with clearance angles designed so that the cutting edge can contact the workpiece without the rest of the tool dragging on the workpiece surface. The angle of the cutting face is also important, as is the flute width, number of flutes or teeth, and margin size. In


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order to have a long working life, all of the above must be optimized, plus the speeds and feeds at which the tool is run.

TYPES

Linear cutting tools include tool bits (single-point cutting tools) and broaches. Rotary cutting tools include drill bits, countersinks and counterbores, taps and dies, milling cutters, reamers, and cold saw blades. Other cutting tools, such as bandsaw blades, hacksaw blades, and fly cutters, combine aspects of linear and rotary motion

CUTTING TOOLS WITH INSERTS (INDEXABLE TOOLS)

Cutting tools are often designed with inserts or replaceable tips (tipped tools). In these, the cutting edge consists of a separate piece of material, either brazed, welded or clamped on to the tool body. Common materials for tips include cemented carbide, polycrystalline diamond, and Dept Of Mechanical Engineering

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cubic boron nitride. Tools using inserts include milling cutters (endmills, fly cutters), tool bits, and saw blades. SOLID CUTTING TOOLS

The typical tool for milling and drilling has no changeable insert. The cutting edge and the shank is one unit and built of the same material. Small tools cannot be designed with exchangeable inserts. HOLDER

To use a cutting tool within a CNC machine there is a basic holder required to mount it on the machine's spindle or turret. For CNC milling machines, there are two types of holder. There are shank taper (SK) and hollow shank taper (HSK). TOOL SETUP

The detailed instruction how to combine the tool assembly out of basic holder, tool and insert can be stored in a tool management solution.

CUTTING EDGE

The cutting edge of a cutting tool is a very important for the performance of the cutting process. The main features of the cutting edge are: 

form of the cutting edge: radius or waterfall or trumpete



cutting edge angles (free angle and rake angle)

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form and size of the chamfers

The measurement of the cutting edge is performed using a tactile instrument or an instrument using focus variation.

MATERIALS


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To produce quality product, a cutting tool must have three characteristics: 

Hardness: hardness and strength at high temperatures.

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Toughness: so that tools do not chip or fracture.

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Wear resistance: having acceptable tool life before needing to be replaced.[2]

Cutting tool materials can be divided into two main categories: stable and unstable. Unstable materials (usually steels) are substances that start at a relatively low hardness point and are then heat treated to promote the growth of hard particles (usually carbides) inside the original matrix, which increases the overall hardness of the material at the expense of some its original toughness. Since heat is the mechanism to alter the structure of the substance and at the same time the cutting action produces a lot of heat, such substances are inherently unstable under machining conditions. Stable materials (usually tungsten carbide) are substances that remain relatively stable under the heat produced by most machining conditions, as they don't attain their hardness through heat. They wear down due to abrasion, but generally don't change their properties much during use. Most stable materials are hard enough to break before flexing, which makes them very fragile. To avoid chipping at the cutting edge, some tools made of such materials are finished with a sightly blunt edge, which results in higher cutting forces due to an increased shear area, however, tungsten carbide has the ability to attain a significantly sharper cutting edge than tooling steel for uses such as ultrasonic machining of composites. Fragility combined with high cutting forces results in most stable materials being unsuitable for use in anything but large, heavy and rigid machinery and fixtures. Unstable materials, being generally softer and thus tougher, generally can stand a bit of flexing without breaking, which makes them much more suitable for unfavorable machining conditions, such as those encountered in hand tools and light machinery.

TOOL MATERIAL AND THEIR PROPERTIES CARBON TOOL STEELS


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Unstable. Very inexpensive. Extremely sensitive to heat. Mostly obsolete in today's commercial machining, although it is still commonly found in non-intensive applications such as hobbyist or MRO machining, where economy-grade drill bits, taps and dies, hacksaw blades, and reamers are still usually made of it (because of its affordability). Hardness up to about HRC 65. Sharp cutting edges possible. HIGH SPEED STEEL (HSS) Unstable. Inexpensive. Retains hardness at moderate temperatures. The most common cutting tool material used today. Used extensively on drill bits and taps. Hardness up to about HRC 67. Sharp cutting edges possible. HSS COBALT

Unstable. Moderately expensive. The high cobalt versions of high speed steel are very resistant to heat and thus excellent for machining abrasive and/or work hardening materials such as titanium and stainless steel. Used extensively on milling cutters and drill bits. Hardness up to about HRC 70. Sharp cutting edges possible.

CAST COBALT ALLOYS

Stable. Expensive. Somewhat fragile. Despite its stability it doesn't allow for high machining speed due to low hardness. Not used much. Hardness up to about HRC 65. Sharp cutting edges possible. CEMENTED CARBIDE Stable. Moderately expensive. The most common material used in the industry today. It is offered in several "grades" containing different proportions of tungsten carbide and binder (usually cobalt). High resistance to abrasion. High solubility in iron requires the additions of tantalum carbide and niobium carbide for steel usage. Its main use is in turning tool bits although it is very common in milling cutters and saw blades. Hardness up to about HRA 93. Sharp edges generally not recommended.


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CERAMICS Stable. Moderately inexpensive. Chemically inert and extremely resistant to heat, ceramics are usually desirable in high speed applications, the only drawback being their high fragility. Ceramics are considered unpredictable under unfavorable conditions. The most common ceramic materials are based on alumina (aluminium oxide), silicon nitride and silicon carbide. Used almost exclusively on turning tool bits. Hardness up to about HRC 93. Sharp cutting edges and positive rake angles are to be avoided. CERMETS Stable. Moderately expensive. Another cemented material based on titanium carbide (TiC)or titanium carbonitride(TiCN). Binder is usually nickel. It provides higher abrasion resistance compared to tungsten carbide at the expense of some toughness. It is far more chemically inert than it too. Extremely high resistance to abrasion. Used primarily on turning tool bits although research is being carried on producing other cutting tools. Hardness up to about HRA 94. Sharp edges generally not recommended.

CUBIC BORON NITRIDE (CBN) Stable. Expensive. Being the second hardest substance known, it is also the second most fragile. It offers extremely high resistance to abrasion at the expense of much toughness. It is generally used in a machining process called "hard machining", which involves running the tool or the part fast enough to melt it before it touches the edge, softening it considerably. Used almost exclusively on turning tool bits. Hardness higher than HRC95. Sharp edges generally not recommended DIAMOND Stable. Very expensive. The hardest substance known to date. Superior resistance to abrasion but also high chemical affinity to iron which results in being unsuitable for steel machining. It is used where abrasive materials would wear anything else. Extremely fragile. Used almost Dept Of Mechanical Engineering

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exclusively on turning tool bits although it can be used as a coating on many kinds of tools. Sharp edges generally not recommended.

WELDING

The assembly of base table are done by the process of welding. In this case the process is done by “Arc Welding”. Arc welding is type of welding that uses a welding power supply to create an

electric arc between an electrode and the base material to melt the metal at the welding point. They can use either direct or alternating current, and consumable or non consumable electrode


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WELDING MACHINES

TYPES OF WELDING MACHINES

Welder machines come in all shapes and sizes from the small home workshop welder to industrial welding machines used for car manufacture and specialized industries.

MIG WELDING MACHINES

– Regarded as the most versatile and the most common welding machine in home workshops and

industry. Can be used for welding several different metals including mild steel, stainless steel and aluminium. Top models include Miller, Lincoln and Hobart.

TIG WELDING MACHINES

– More specialized than mig welders tig machines are used for precision work and can weld

more types of metal than any other process. Metals suitable to tig weld are stainless steel, mild steel, aluminum,copper, bronze, brass, gold, magnesium, chromoly, and nickel alloys. Tig welding gives pure clean welds without splatter, sparks and smoke fumes. Ideal for welding metal artwork, aluminum cycle and motorcycle frames plus clean stainless welding for applications such as food processing equipment.


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ARC WELDERS.

Basic weld machine that have been around for many years. Can be purchased for very little money these days and in the right curcumstances can be very useful. Ideal for repair work where a mig welder is not suited to such as on site and field work where portability is needed and also where welding gasses can be blown away due to wind.


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SPOT WELDING MACHINES

-Spot Welding is a common resistance welding technique utilized to join 2 to 4 overlapping steel sheets that are anywhere up to 3 mm thick each. In many applications using just 2 overlapping metallic sheets, the sheet thickness could be as much as 6 millimeters. A pair of electrodes are concurrently utilized to secure the metal sheets together and move current throughout the sheets. Some great benefits of the technique consist of effective power use, restricted workpiece deformation, higher manufacturing rates, simple automation, with no necessary filler materials. Spot welding is employed instead of more expensive mechanized fastening, for example riveting and screwing, and when disassembly for maintenance is not needed. Whilst weld strength at each weld spot is significant , the fact that the weld spots don’t form a continuing seam ensures that the general sturdiness is usually considerably less than with welding techniques, making the procedure suited to only specific applications. It’s utilized broadly within the motor vehicle

industry where cars can have several thousand spot welds.


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PLASTIC WELDING MACHINES

Plastic welding is one of the most innovative and different kinds of processes. It is specially designed for welding plastic materials, which are otherwise difficult to weld using conventional welding processes. For how to weld plastic parts, the films are fused and pressure is applied against them. The technique of plastic welding is diverse in nature, and has many variants with high number of applications for industrial use.


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DRILLING

DRILLING is easily the most common machining process. Drilling involves the creation of holes that are right circular cylinders. This is accomplished most typically by using the twist drill. The chips must exit through the flutes to the outside of the tool. The cutting front is embedded within the work piece, making cooling difficult. The cutting area can be flooded, coolant spray mist can be applied, or coolant can be delivered through the drill bit shaft

GRINDING

Grinding is the finishing process used to improve surface finish, abrade hard materials, and tighten the tolerance on the flat and cylindrical surface by removing the small amount of material. Information in this section is organised according to the sub categories link in the menu bar to the left. In grinding the abrasive material rubs against the metal part and removes the tiny pieces of material. The abrasive material is typically on the surface of the wheel or belt and


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abrades in a way similar to sanding. On a microscopic scale, the chip formation in grinding is same as that found in other machining processes.

TYPES 

Belt grinder, which is usually used as a machining method to process metals and other materials, with the aid of coated abrasives. Analogous to a belt sander (which itself is often used for wood but sometimes metal). Belt grinding is a versatile process suitable for all kind of applications, including finishing, deburring, and stock removal.



Bench grinder, which usually has two wheels of different grain sizes for roughing and finishing operations and is secured to a workbench or floor stand. Its uses include shaping tool bits or various tools that need to be made or repaired. Bench grinders are manually operated.



Cylindrical grinder, which includes both the types that use centers and the centerless types. A cylindrical grinder may have multiple grinding wheels. The workpiece is rotated and fed past the wheel(s) to form a cylinder. It is used to make precision rods, tubes, bearing races, bushings, and many other parts.



Surface grinder, which has a head that is lowered to a workpiece, which is moved back and forth under the grinding wheel on a table that typically has a controllable permanent magnet (magnetic chuck) for use with magnetic stock (especially ferrous stock) but can have a vacuum chuck or other fixturing means. The most common surface grinders have a grinding wheel rotating on a horizontal axis cutting around the circumference of the grinding wheel. Rotary surface grinders, commonly known as "Blanchard" style grinders, have a grinding head which rotates the grinding wheel on a vertical axis cutting on the end face of the grinding wheel, while a table rotates the workpiece in the opposite direction underneath. This type of machine removes large amounts of material and grinds flat surfaces with noted spiral grind marks. It can also be used to make and sharpen metal stamping die sets, flat shear blades, fixture bases or any flat and parallel surfaces. Surface grinders can be manually operated or have CNC controls.



Tool and cutter grinder, which usually can perform the minor function of the drill bit grinder, or other specialist toolroom grinding operations.


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Jig grinder, which as the name implies, has a variety of uses when finishing jigs, dies, and fixtures. Its primary function is in the realm of grinding holes for drill bushings and grinding pins. It can also be used for complex surface grinding to finish work started on a mill.



Gear grinder, which is usually employed as the final machining process when manufacturing a high-precision gear. The primary function of these machines is to remove the remaining few thousandths of an inch of material left by other manufacturing methods (such as gashing or hobbing).



Die grinder, which is a high-speed hand-held rotary tool with a small diameter grinding bit. They are typically air driven (using compressed air), but can be driven with a small electric motor directly or via a flexible shaft.

Angle grinder, another handheld power tool, often used in fabrication and construction work.


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ALUMINIUM Sheet metal is metal formed by an industrial process into thin, flat pieces. Sheet metal is one of

the fundamental forms used in metalworkingand it can be cut and bent into a variety of shapes. Countless everyday objects are fabricated from sheet metal. Thicknesses can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate. Aluminum is also a popular metal used in sheet metal due to its flexibility, wide range of options, cost effectiveness, and other properties. The four most common aluminium grades available as sheet metal are 1100-H14, 3003-H14, 5052-H32, and 6061-T6. Grade 1100-H14 is commercially pure aluminium, highly chemical and weather resistant. It is ductile enough for deep drawing and weldable, but has low strength. It is commonly used in chemical processing equipment, light reflectors, and jewelry. Grade 3003-H14 is stronger than 1100, while maintaining the same formability and low cost. It is corrosion resistant and weldable. It is often used in stampings, spun and drawn parts, mail boxes, cabinets, tanks, and fan blades. Grade 5052-H32 is much stronger than 3003 while still maintaining good formability. It maintains high corrosion resistance and weldability. Common applications include electronic chassis, tanks, and pressure vessels. Grade 6061-T6 is a common heat-treated structural aluminium alloy. It is weldable, corrosion resistant, and stronger than 5052, but not as formable. It loses some of its strength when welded. It is used in modern aircraft structures.

CAR DIKKI AIR CYLINDER

Have you ever tried lifting the trunk lid (sometimes called tailgate, hatch, or boot) of your car with just one finger? How come you can lift a heavy piece of metal and glass with so little force? The answer, if you didn't know already, lies in those clever piston-like hinges that support the lid


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either side. They're called gas springs (or gas dampers) and they make our lives a whole lot easier in all sorts of ways If you're sitting on an office chair right now, there's probably a gas spring underneath your body. Release the height lever and you'll feel (and probably hear) the gas in the spring being compressed as the seat gently falls down. Gas springs have loads of other uses too. Let's take a closer look at these handy gadgets and find out how they work!

Why do we need gas springs?

Suppose there were no springs on the trunk lid of your car. It would be really heavy to lift, for one thing. There'd be nothing to hold it up in the air when you wanted to load in your shopping, which would be a real nuisance. And, if you let the lid go, it would crash down onto your car's bodywork, probably doing a lot of damage in the process. Now we could put a normal metal spring on the lid, but that wouldn't help so much. It would need to be a very stiff and heavy spring, so it would take a huge amount of effort to lift the lid high in the air. The higher you lifted it, the harder it would get to lift any further. With the lid opened up fully, the spring would be stretched out so much that it would pull straight back down again! How a gas spring works

The basic idea

A gas spring is a bit like a super-sturdy version of a bicycle pump, only it's filled with pressurized nitrogen gas (the major constituent of the air around us) and oil and completely sealed up so they can't escape. The gas allows the spring to store energy, while the oil damps (slows and smooths) the movement of the piston and also provides lubrication. Just like in a bicycle pump, there's a tight-fitting piston mounted on a rod that can slide back and forth inside a cylinder (made from heavy gauge steel, not light plastic as in a bicycle pump). Dept Of Mechanical Engineering

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Push on a gas spring and you force the piston rod and piston into the cylinder and this compresses the gas. Stop pressing and let go and the pressure of the gas pushes the piston back out again. So far, that sounds just like a bicycle pump — but it's working in a different way. Unlike with a bicycle pump, gas inside the cylinder can actually flow through or around the piston from one side to the other as it moves back and forward. Exactly how this happens varies from one design of gas spring to another; usually the piston has one or more holes or valves in it. Now if the piston can move through the gas, you might think it isn't compressing the gas at all. But don't forget that the whole cylinder is completely sealed. When the piston rod is inside the cylinder, it's taking up room that the gas previously occupied. In other words, when a gas spring is fully pushed in, you've compressed the gas inside by an amount equal to the volume of the piston rod. If the piston rod occupies virtually the whole cylinder, you can see that the gas is getting compressed quite substantially. The gas pressure can be very high, typically up to about 170 times normal atmospheric pressure!


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How a gas spring generates a force

There's one particularly important difference between a bicycle pump and a gas spring — and that's the way in which force is generated when you push in the piston. Suppose you cover the end of a bicycle pump and push on the piston. You'll immediately find there's a force pressing outward against your hand, because the pressure of the gas on one side of the piston is higher than the pressure of the air on the other side. In other words, the force is produced by a difference in pressure on the two sides of the piston.

In a gas spring, things are different. Fluid can flow around or through the piston from one side to the other, so the pressure is the same on both sides. However, the pressure acts over a greater area on the inside surface of the piston than on the outside (because the piston rod takes up some room). That means there's more force on the inside face than on the outside — and that's how a gas spring produces a force when you push it in. In other words, the force is produced by a difference in area.


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The size of the force a gas spring produces (sometimes called its "output force") is equal to the area of the piston times the internal pressure. The output force is reduced by friction between the piston and the cylinder (which is one reason why lubrication is important) and increases with temperature (because, according to the basic gas laws, higher temperatures increase the pressure of the gas inside the cylinder). Much like metal springs, gas springs come in all different sizes. You can choose one with just the right size of cylinder and piston and the right amount of gas pressure to give precisely as much force in the spring as you need to do a particular job. To support the trunk lid of a car, you need the two gas springs either side to provide roughly as much force when they're compressed as the weight of the lid. For a gas-lift office chair, you need the spring to provide a little bit more force than the weight of the seat. In most chairs, the spring doesn't actually support the person's weight. Instead, it typically has a lever attached that grips and locks at a certain height, preventing the seat from moving up or down any further. The spring is simply designed to let the seat move up and down gently without your having to supply much force.

Gas springs as dampers

One thing you'll notice about gas springs is that they work slowly and smoothly. The end of the piston is designed so the fluid inside the cylinder (gas and liquid) can flow through or around it very slowly. Different springs are designed in various different ways and some pistons are arranged so the fluid will flow more quickly past them when the spring moves in one direction than when it moves the opposite way. For example, when the piston is compressed into the cylinder, the end of the piston may be designed to close up a valve so fluid can flow through it only very slowly, reducing the speed at which the piston can move. When the piston moves the other way, the valve can be designed to open up so fluid will travel past it more quickly, allowing the piston to move much faster. Gas springs are usually designed with a particular size of load in mind so they expand very smoothly at a particular rate (so many centimeters or inches per second).


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Gas springs as energy reservoirs

A gas spring's job is to make your life easy — and it does it by storing energy (when there's plenty

available — usually when you're lowering something heavy) and releasing that energy (when you need extra help — usually when you're lifting something up). Think of a gas spring as a kind of mechanical battery that stores and releases energy by squeezing and releasing a gas and you can see why it's so useful. What's happening with energy when you lift a heavy trunk lid that has no springs of any kind? There's a lot of mass in the steel andglass lid so it takes a lot of energy to raise it up against the force of gravity, which is constantly trying to pull it back down. Once the lid is high in the air, it has stored potential energy : you can release the lid and it'll crash straight back down again. If that happens, the potential energy is instantly converted into kinetic energy, as the lid accelerates, and then heat and sound energy when the lid smashes onto the car's body. What a waste! With a couple of gas springs on either side of the lid, it works a different way. Now, when you gently lower the lid, the weight of the metal and glass forces the pistons into the gas springs, compressing the nitrogen gas inside. As you lower the lid, the potential energy it had when it was up in the air is slowly converted into potential energy inside the gas springs and stored there. Next time you want to raise the lid, that potential energy is waiting inside the springs ready to help you. Release the lid catch, lift the lid gently, and the potential energy stored in the gas springs is slowly released. The pistons push out from the gas springs and help you lift the lid back up again.

How a gas spring stores and releases energy

1. The spring is fixed to a mounting bracket that can move back and forth with the door, lid (or whatever else it's attached to). Dept Of Mechanical Engineering

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2. When you apply a force, the bracket moves inward and pushes on the piston rod (blue), which moves into the cylinder (black). 3. The piston rod pushes the piston (red) through the gas (gray). The piston makes a tight seal as it slides along the cylinder, but gas (and oil) can flow through it from (in this case) the right side to the left (and back again). 4. The lubricant oil (yellow) greases the piston as it slides in and out. 5. Tight seals (usually O-rings) allow the piston rod to move freely but keep the lubricant oil and the gas safely inside the cylinder. 6. The nitrogen gas (gray) inside the cylinder is compressed as the piston moves in by an amount equal to the volume of the piston rod. Note that the gas is compressed on both sides of the piston, to exactly the same pressure, as the piston moves in (that's

different to a bicycle pump where the gas is compressed only on one side). 7. The other mounting bracket stays in the same place throughout. When you let the spring move outward, the pressurized nitrogen gas expands, the piston moves back the other way, and the stored energy is released .

Why use a gas spring?

A gas spring can do a similar job as an ordinary metal spring, though it has a number of

advantages. Because of the high pressure of the gas inside it, a gas spring can be much more compact than a metal spring that would provide the same amount of force. Gas springs expand and contract more smoothly than metal springs and can be designed to open and close at an exact and constant speed (unlike metal springs, which contract faster when they are extended further and can be very unpredictable). Mechanically, gas springs are simple and have few moving parts, so they are relatively cheap, extremely reliable, and often last many years without any maintenance at all. Metal springs are more likely to break through repeated stretching and releasing (loading and unloading) because of fatigue.


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DESIGN CALCULATION: Area x Pressure = Force Output F = P X A Consider the weight of human sitting on chair = 100 kg. = 981 N 981 = P x π r2 P= 981/ π 102 P = 3.12 N/mm2 DESIGN OF CYLINDER: Now for thickness of cylinder wall of cylinder, Hooks law, We have, t = pd/2 σtensile Where p = internal

pressure= 3.12N/mm2 , d = diameter of cylinder=20 mm selected

σultimate = 300 N/mm2 aluminium alloy Considering factor of safety as 4. We get permissible

stress = ultimate stress/factor of safety

σtensile =300/4 σtensile = 75 N/mm2 Inputting these



value in the thickness formula, We get, t = 3.12 x 20/2 x 75 = 62.4/150= 0.416 mm. t = 0.5 mm

DESIGN OF BOLT: (TENSION) Bolt is to be fastened tightly also it will take load due to a rotation. Stress for C-45 steel ft =420 kg/cm2. The standard nominal diameter of the bolt is 9.31 mm. From table in design data book, diameter corresponding to M10 bolt is 8 mm Let us check the strength: Also, initial tension in the bolt when the belt is fully tightened P = 981 N is the value of force P = 981 N Also, P = Π /4 dc2 x ft 981 x 4 Ft = ------------------------------ =

3924/201 3.14 X (8)2 Ft = 19.51N/mm2 The calculated ft is less than the maximum ft hence our design is safe. σt = σ b=135 N/mm2 σ s = 67.5 N/mm2 Dept Of Mechanical Engineering

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ADVANTAGES

1. The movements of the worker are copied by the exoskeleton, i.e. the limbs of the human and the exoskeleton are aligned during motion. 2. No external power source required. 3. Heavy objects can be lifted for long period of time. 4. Increases efficiency of operater. 5. Robust in design,requires less space,can be assembled & dissassembled easily

DISADVANTAGES

1. Distinction of intended from unintended movements is often difficult and results in systems with many different kinds of sensors and complex signal processing. 2. But the cooperation and function allocation, man-machine information exchange, real-time motion planning and safety control are the difficulties faced by building such a control strategy. 3. Free body motions are restrained. 4. May require costly materials like carbon-fibre,aluminium.


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GANTT CHART GANTT CHART FOR SEED SOW MACHINE

The Gantt chart is designed to empower production planners to control and optimize the production plan. The Gantt chart makes the flow of operations transparent and makes it easy to adjust the production schedule while taking into account material or resource shortages. This helps planners make the best use of available resources, minimize work in progress, and optimize throughput times for production orders. January 2018

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A Gantt chart is a visual representation of scheduled activities within a defined time interval. The activities are scheduled on resources that have capacity defined by a capacity calendar. The following types of activities can be shown in the Gantt chart. 

Jobs from production orders that are job scheduled.



Jobs from planned production orders.



Job scheduled project activities of type Hour forecasts.

The Gantt chart can be opened in two different views, Order view and Resource view . In Order view, activities are grouped under production orders. This can be useful, for example, if you

want to maintain an overview of all the jobs belonging to the same orders. In Resource view all jobs are grouped under individual resources. This view can be useful when optimizing the plan at a resource level, for example, a machine or a group of machines. The Gantt charts shown in the illustrations below show Order view and Resource view with these key elements: 1. Gantt chart activity 2. Material shortage icon 3. Material availability icon 4. Order delivery date icon 5. Capacity bar

ACTIVITIES

The activities appear as bars and are organized in a time scale grid with a scheduled start and end time, making the length of the bars proportional to the time that is necessary to complete the activity. The activities are shown according to a time scale. You can adjust the time scale on the menu where you select a start and end date and a time unit, for example, hours or days. By Dept Of Mechanical Engineering

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adjusting the time scale you can set focus on a time interval in which you want to manage activities. To get a better overview, there are different options for controlling the color of the activities. You can configure an individual color for activities, use the theme color that is the general color theme used for the application, or set up the color to be controlled by the color code for production orders. The time interval for activities has a background shade. Periods with a white shade indicate a time interval with defined capacity on the resource for the activity, whereas periods with a grey shade indicate time intervals with no capacity defined. On the left side of the chart there is additional information about the activity, for example, the resource on which the activity is scheduled and production order number. The connection between jobs belonging to the same order is shown with an arrow. You can get more information about an activity in the activity dialog box. To open the dialog box, double-click the activity or select the information menu. In the activity dialog you can see the scheduled start and end date, and time information about which materials the activity is planned to consume. The activities can be grouped in Grouping levels. The Grouping levels are hierarchical and can be used to make a logical grouping of activities. For example, if you have a layout where manufacturing activities are grouped by Site, Production units, Resource groups, and Resources, you can use the Grouping levels to group the activities according to that layout. The grouping levels can be expanded and collapsed either on the individual grouping level or for all levels in the chart by using the Expand all and Collapse all buttons on the menu. You can also configure the grouping levels to be expanded or collapsed when the chart is opened.

Material availability The Gantt chart can be set up to provide the planner with detailed information about material status for the individual activities. For example, this can be helpful if material is delayed and is Dept Of Mechanical Engineering

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affecting the production plan. In this case, the material issues will be highlighted in the Gantt chart to help the planner to understand consequences and make necessary adjustments. A job will appear with a material shortage icon if the schedule start date of the job is later than the material availability date for materials consumed by the job. The material availability date is calculated based on the pegging information in the dynamic master plan. The material shortage icon will for example appear on a job that is consuming a material that is pegged against a purchase order that has a receipt that is later than the planned start date of the job.

Indicator of material availability date When you set up the chart to show jobs with material shortages an icon for showing the material availability date for the job can also be shown. The icon will only be shown if the material availability date is within the defined time interval of the chart. If the material availability date lies outside the defined time interval, then more detailed material availability information can be retrieved from the material list in the job dialog box. In the list there is also an icon showing late materials for the job. You can reschedule a job using the material availability date as a start date.

Indicator of order delivery date This icon indicates the delivery date for a production order. The icon is only visible in the Order view.

Capacity bar You can configure the chart to show a resource capacity bar. This bar provides an overview of the resource capacity for an activity in the defined time interval of the chart. The capacity bar is not shown for periods of the time where the resource is not booked. In periods where the resource is booked to capacity, the capacity bar is shown as a solid bar. In periods where the resource is overbooked, the bar will appear thicker and in a red color. For example, if two jobs overlap, the capacity bar will indicate an overbooking in the time interval where there is an overlap. The capacity bar is updated dynamically when you schedule a job. You enable the Dept Of Mechanical Engineering

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capacity bar on the Show capacity bar menu. It can only be shown in Resource view . If you want to get a more detailed view of the capacity load on a resource, use the Capacity load chart, which can be opened from the menu or the context menu for a selected activity.

Job scheduling in the Gantt chart The Gantt chart offers different options for making adjustments to the production plan. In the Gantt chart, you can re-schedule activities as a drag-and-drop interaction or from a schedule menu. In the planning process, you can take resource capacity, resource capabilities, and material constraints into account.

Schedule a job as a drag-and-drop interaction You can re-schedule job within the defined time interval as a drag-and-drop interaction. You can only re-schedule the job on the same resource, and you can only schedule one job at a time.

Schedule a job from the menu On the Schedule jobs menu, you can schedule one or more selected job in the chart based on a scheduling direction and a scheduling date time. There are three available schedule directions. 

Forward from scheduling date



Backward from scheduling date



Forward from material availability date

It is not possible to schedule a job outside the defined time interval of the Gantt chart. If you do that, the job will be left unscheduled and you will receive the error message, "Could not schedule the job within the loaded time period."

Schedule previous jobs In a network of activities, such as jobs belonging to the same production order, you can use the Schedule previous jobs function to schedule the previous jobs relative to a selected job in Dept Of Mechanical Engineering

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the network. In the following example, the highlighted activity is the selected job. The diagram shows before a previous job is scheduled and after the previous job is scheduled.

Schedule next jobs You can use the Schedule next jobs function to schedule the next jobs relative to a selected job in a network of activities. In the following example, the highlighted activity is the selected job. The diagram shows before the next job is scheduled and after the next job is scheduled. You can use the Schedule around job function to schedule the next job and the previous job relative to a selected job in a network of activities. In the following example, the highlighted activity is the selected job. The diagram shows before a job is scheduled and after the job is scheduled.

Arrange jobs You can use the Arrange function to arrange selected activities on the same resource. These activities can be in the same network of activities, but can also belong to different networks. When you use the arrange function the time gaps between the selected activities will be eliminated. You can use this function to optimize the capacity utilization of the resources. The diagram shows before a job is scheduled and after the job is scheduled.

Reassign activities from one resource to another You can reassign a job from one resource to another. This can be useful in situations where a machine is out of order or overbooked, and you need to find another available resource that can do the job. Dept Of Mechanical Engineering

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Reassigning an activity as a drag-and-drop interaction In the Resource view, you can reassign an activity to a different resource in the Gantt chart as a drag-and-drop interaction. You do that by selecting the row in which the activity is scheduled. After the row is selected you can drag the row to the resource in the chart grouped under a different resource grouping level.

Reassigning an activity from the Schedule jobs menu You can reassign a job from the Schedule job dialog box opened from the Schedule job menu. From this menu you can only reassign a job to a resource that is already loaded to the Gantt chart. If you only select one job, then the drop down for the resource will be sorted by applicable resources. If you select more jobs, then there will be no information about applicable resources from the resource list.

Load additional resources to the Gantt chart In the Resource view , you have an option to load additional resources to the Gantt chart. This can be useful if you want to find an alternative resource for a job that is scheduled on a machine that is overbooked or broken down. On the Load additional resources page, you will get a list of resources that are date efficient as of the date the list is opened. Applicable resources, relative to a selected job in the Gantt chart, will be listed first. If you have multiple jobs selected, prior to opening the list, no indication of applicable resources will be shown. On the Load additional resources page, you can select one or more resources, that will be loaded to the Gantt chart

when you confirm your selection. If there are no jobs scheduled on the selected resource in the time interval of the Gantt chart, then the resource will be placed under a resource grouping level in the bottom of the list of activities in the Gantt chart.


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APPLICATIONS

1. Medical /Rehabilitation purposes where the devices are aimed to support physically weak, injured, or disabled people to perform a wide range of motions. 2. A small number of exoskeletons have also been designed for military applications for soldiers. 3. For Industrial application to lift or carry heav y loads. 4. In civilian areas, exoskeletons could be used to help fire fighters and other rescue workers survive dangerous environments.

FUTURE SCOPE

The basic operation of this machine to reduce fatigue by sustaining the weight of the wearer in a similar fashion as that by a regular chair As your leg weakness progresses due to increasing in your age, your health care team may recommend equipment known as ambulation aids and bracing to help you with walking. Other devices can help give you needed support as the muscles in your neck and arms weaken. There may be a use of such exoskeletons which can give more effect than braces and ambulation aids. The specific aid or device that's best for you depends on the extent of the weakness and your willingness to use such a device. Using such instruments for walking climbing, doing work is safe and you‟re confident that you won‟t fall. For some, this

means having an attendant or using an assistive device when walking shor t distances. Such instruments are going to bring more flexibility, mobility and most importantly the confidence Apart from in medical therapy and military sector, active or hoses or exoskeletons offer other applications, for example as a power booster during assembly work in production. They act here as a strength support device to prevent signs of fatigue that occur especially when performing repetitive actions.


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CONCLUSION

The aim of this project was to design and develop a lower body exoskeleton i.e. chairless chair. With the help of the guide of our project and the departmental head. It was a nice opportunites and to develop a such things that is essential to the industrial worker for long hours duration. It is a simple device which consists of mechanism and linkages to transfer the motion no external battery source is required.


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Development of Noonee Chairless Chair

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