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1. INTRODUCTION

Every four year the world cup inspires million. The 2014 World cup not be kicked off

by the legs of Cristiano Ronaldo or Lionel Messi Rather be a person who never thought he

can walk again. This impossible can be made possible by using mechanical exoskeleton.

Exoskeleton it take signals from the user brain activity to power his\her step forward. The

exoskeleton is an electromechanical structure worn by operator and matching the shape and

functions of human body. It is able to augment the ability of human limb and/or to treat

muscles, joints, or skeletal parts which are weak ineffective or injured because of a disease or

a neurological condition. Moreover, it merges the machine power and the human intelligence

in order to enhance the intelligence of the machine and to power the operator. The

exoskeleton works mechanically in parallel with human body and can be actuated passively

and or actively. The Walk Again Project is in countdown to show the world for the first time

one of the great achievements so far: during the opening ceremony of the World Cup on June

12 at Arena Corinthians in So Paulo, a paraplegic young adult will make a symbolic effort

using an exoskeleton, or robotics garment, controlled by his brain activity. It will be just the

beginning - as the projects leader, neuroscientist Miguel Nicolelis, believes of a future in

which people with paralysis may abandon the wheelchair and literally walk again.

Fig 1: Walk again

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2. HISTORY

The history of the active exoskeleton can be traced back to the 1960s. The US military

had developed several exoskeletons to augment and amplify the soldier ability for military

purposes. Then, the General Electric Company developed two-armed masterslave

manipulator used for handling radioactive equipment. The master is an exoskeleton type

robot worn by the operator and its motion was reproduced by the two-arm slave unit.

Moreover, the John Hopkins University designed the upper limb exoskeleton type to help

elbow flexion of paralyzed people. Almost at the same time, the Beograd anthropomorphic

exoskeleton was designed for lower limb application. The development of the exoskeleton

has been increased in various implementations.

Fig 2: Ceremonial Kick Off World Cup Football-2014

3. THREE TYPES OF EXOSKELETON

The exoskeleton is the most advanced technological realization and was designed to

enable real time interaction of the brain with the robotics garment. The first prototype tests

were successfully completed. The exoskeletons are initially used by U S military agencies to

enhance the capability of the soldier. Now it is come into the advanced rehabilitation

techniques. The implementation of the exoskeleton can be classified into three main groups:

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Human power augmentations

Haptic interactions

Rehabilitations

Fig 3: Types of exoskeletons

3.1 HUMAN POWER AUGMENTATIONS

Human power augmentations exoskeletons enhance the users capacity on doing

things. For example in the figure you can see a man carrying a wait around 80 kg in his one

hand with one hand. Kanazawa Institute of Technology developed the full body exoskeleton

for augmenting the nurses power to take care of the patient. In addition, University of

Tsukubahas developed some generations of Robot Suit HAL (Hybrid Assistive Limb) to

physically support a users daily activities and heavy work. The BLEEX has been designed to

augment the human limb so that the wearer is able to carry significant load easily over

various terrains.

Fig 4: Man carrying weight of 80 kg

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3.2 HAPTIC INTERACTIONS

Virtual reality (VR) sometimes referred to as immersive multimedia, is a computer-

simulated environment that can simulate physical presence in places in the real world or

imagined worlds. Virtual reality could recreate sensory experiences, including virtual taste,

sight, smell, sound, touch, etc. Haptic interaction exoskeleton implements virtual reality to

the user. It takes the users motion and position of eye, hand, leg etc with various sensor and

give input to control system the control system will give outputs to the user. Nowadays the

importance of virtual reality system increase due its cost effectiveness in analysis.

Fig 5: Virtual Reality using exoskeleton

3.3 REHABILITATION

The rehabilitation is the last exoskeleton application. The rehabilitation exoskeletons

have been developed for many purposes. They are implemented in either the lower limb for

gait rehabilitation or the upper limb. The treadmill gait trainer is one implementation of gait

rehabilitation. These types have very much social important because these exoskeletons have

the capacity to interpret brain signals and allow a paraplegic person to walk again. A

technology that would enable reading electrical signals produced by neurons in the brain and,

from these signals, captures a motor control that could be used by the machine. Then it was

necessary to send the signals back from the robot to the brain, completing the control cycle.

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Fig 6: Rehabilitation using exoskeletons

4. DEVELOPMENT OF BRAIN MACHINE INTERFACE

It is important to interpret the signal from brain to control the machine and there are

lakhs of signals generating inside the brain and how this difficulty can overcome? The worst

thing is that you cannot implement an electrode deeply inside the brain so it needed to be deal

with the outer core that is the cerebral cortex. The cerebral cortex is the outermost layered

structure of neural tissue of the cerebrum (brain), in humans and other mammals. It covers

the cerebrum, and is divided into two cortices, along the sagittal plane, covering the left and

right cerebral hemispheres. The medial longitudinal fissure is a deep groove that separates

these two hemispheres. The cerebral cortex plays a key role in memory, attention, perceptual

awareness, thought, language, and consciousness. How neuron in the cerebral cortex

outermost layer of the brain are involved in the mode of learning. It is referred to as gray

matter as it consists of cell bodies and capillaries and contrasts with the underlying white

matter that consists mainly of the white myelinated sheaths of neuronal axons. In large

mammals the surface of the cerebral cortex is folded, giving a much greater surface area in

the confined space of the skull. A fold or ridge in the cortex is termed a gyrus (plural gyri)

and a groove or fissure is termed a sulcus (plural sulci). In the human brain more than two-

thirds is buried in the sulci. The phylogenetically most recent part of the cerebral cortex, the

neocortex (also called isocortex), is differentiated into six horizontal layers; the more ancient

part of the cerebral cortex, the hippocampus, has at most three cellular layers.

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Fig 7: Portions of brain controlling different limps

The cerebral cortex has separate space for controlling a particular limb. So the

researchers can fix the electrode at a particular position and read the signals from that part for

the corresponding motion of the limb.

5. RESEARCH

Dr Miguel Nicoleles of Duke University and his colleagues set out to study how

neuron in the cerebral cortex outermost layer of the brain are involved in the mode of

learning .The researchers first pick up a monkey and study its responses. For this they use a

throwing motion. For an entire year they record data from 15 to 100s of neurons using

electrode implanted in the part of the cortex that involved in moving the arm and the hand.

Those recordings illuminated something essential.

Fig 8: Research

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Behind the monkeys throwing motion produce consistent pattern in brain activity. The

same pattern is observed each time when monkey move its arms, with this data the team

developed a brain machine interface a system that interprets what user want from their brain

activity and then turn that activity into commands. So that they can control everything from a

cursor on a computer screen to the movements of a robotic arm.

Fig 9: Signals From Monkeys brain

6. LOPES REHABILATION EXOSKELETON

The redesigned exoskeleton robot mainly consists of a brain signal reading helmet,

shoulder motion support part a wrist force sensor and a mobile wheel chair. The exoskeleton

used in world cup uses an EEG CAM helmet rather than implanted electrodes to read brain

activity. The pattern will be interpreted by computer algorithm and the exoskeleton hydraulic

pumps power it movement. The helmet has to be exactly fit to the patients head in the inside,

helmet protects the user head in case of a fall also hold the electrodes perfectly in place to

read brain activity. Scientist did a 3-D scan of patient head and models it by using advanced

modeling software and use of 3-D printer for precision.

An LED system is used for EEG feedback so that their imagination to move the left

side or right side. The LED system on each side of eye so that EEG system actually tells

thinking left or right.

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7. PARTS

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8. MECHANISM

Recovery from stroke is difficult and the treatment is prolonged hence the

Exoskeleton Suit H1 is designed and proposed in this paper. Enabling these people to walk

using a wearable Exoskeleton Suit which is cost-effective and will enable walking is the real

motive behind the ideology. The exoskeleton consists of Pneumatic Actuators,

Potentiometers, Compressed Air Supply, Micro-Controllers, Flow Control Valve, and DC

Motor with Encoder (Quadrature and Absolute type) as key Components. It is Pneumatically

Powered instead of a high torque motor. The reason is that it will have a better life and less

battery voltage will be consumed compared to a high torque motor and thus making it eco-

friendly. Though Pneumatic actuation will be a bit slower compared to that of a motor, but it

will have a considerable high life.

Fig 10: Block diagram

There are two Pneumatic Actuators which are connected to the body by means of

Body Frame of the suit- One is fixed at the back Thigh muscle and one is fixed at the Calf

muscle. There is a Flow Control Valve which is intermediate between the Actuators and the

Main Air Supply Tank and this is responsible for the Speed of Extension/Retraction of the

Piston Cylinder and thereby the Walking Speed of the Person. If this is not used then there

will be sudden extension/retraction which might damage the muscles and skin tissues and

even affect the dynamics of the Structure. The DC motor is mounted on the knob of FCV

(Flow Control Valve).An Encoder is attached to the rear end of the DC Motor Shaft which

will count the turns it has revolved Clockwise/Anti-Clockwise and send the signal to the

Micro-Controller. The Compressed Air Supply will be in the form of Couple of Bottles which

are Airtight with Check-Valve in it and can be easily carried by the person on the back. The

entire structure is made using Aluminum.

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9. CONTROL ARCHITECTURE

The left brain controls the right limbs whereas the right brain controls the left limbs.

When we walk, there is continuous synchronization between the arms and the legs. Whenever

right leg is put forward, the left arm swings in front and vice versa. Keeping this principle in

mind, the Exoskeleton suit H1 is designed.

Fig 11: Parts of Brain

To get a compliant active exoskeleton controller, the force interaction controllers are

mostly used in form of either the impedance or admittance controllers. The impedance or

admittance controllers can only work if they are followed by either the force or the position

controller respectively. These combinations place the impedance or admittance controller as

high-level controller while the force or position controller as low-level controller. From the

application point of view, the exoskeleton controllers are equipped by task controllers that

can be formed in several ways depend on the aims.

Fig 12: Types of control system

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The exoskeleton control system can be classified into several groups based on the

model, the physical parameter, the hierarchy and the usage. The variation control system

implemented and utilized today need improvement to meet the need of the next exoskeleton

control system such as the assist as needed, the users intention detection, the modularity, the

safety and the stability. All these aspects have to be considered and incorporated in designing

the control system for the exoskeleton to give better performance and better future

implementation.

Fig 13: Exoskeleton parts and functions

10. TACTILE SENSATION IN WALKING AGAIN

For the act of walking to be as close as possible to reality, it is important for the

patient to also have tactile sensation restored in the paralyzed limbs. For this to be possible, a

tactile feedback technology, or artificial skin, was developed as an essential device for

restoring the sense of touch and perception (the ability to recognize the bodys spatial

location) of the lower limbs of patients who will use the exoskeleton to walk again. The

artificial skin, developed by the group of researchers led by Gordon Cheng, consists of

flexible printed circuit boards, each containing pressure, and temperature and speed sensors.

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It is applied on the soles of the feet for the patient, when walking with the exoskeleton, to

receive a tactile stimulation sent to a region of the upper body such as the arms, at every

touch of the foot on the floor. With this transmission from the feet to the arms, the patients

brain is induced to remap the tactile sensations and restore the feeling of stepping on the

floor, walking as if there were no paralysis.

11. CURRENT LIMITATIONS

One of the largest problems facing designers of powered exoskeletons is the supply.

There are currently few power sources of sufficient energy density to sustain a full body

powered exoskeleton for more than a few hours. Non-rechargeable primary cells tend to have

more energy density and store it longer than rechargeable secondary cells, but then

replacement cells must be transported into the field for use when the primary cells are

depleted, of which may be a special and uncommon type. Rechargeable cells can be reused

but may require transporting a charging system into the field, which either must recharge

rapidly or the depleted cells need to be able to be swapped out in the field, to be replaced with

cells that have been slowly charging. Another important limitation is that it is required to

design uniquely for a patient so that all sensors perfectly suited his/her body dimensions.

Currently the exoskeleton suits are highly expensive. A single suit cost around $25k (around

15lakhs Rs). Since it is in direct contact with the body advanced materials that will not affect

the body are required. Moreover there are no standardization techniques for exoskeletons.

Flexibility is another design issue, and which also affects the design of unpowered hard shell

space suits. Several human joints such as the hips and shoulders are ball and socket joints,

with the center of rotation inside the body. It is difficult for an exoskeleton to exactly match

the motions of this ball joint using a series of external single-axis hinge points, limiting

flexibility of the wearer.

Fig 14: Limitations

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12. THE FUTURE OF EXOSKELETONS

There will be a real Iron man in the future with the help of exoskeleton. Stable,

energy-dense power sources allow sustained operation. Exoskeletons will be commonly used

by all military agencies. You will see paraplegic person participating in the sprint walking

through the road as a common man with hidden exoskeleton inside the dress. Miniaturization

of exoskeleton reduces the cost and is available for common man. With the brain reading

machine in the future there will be a wireless device transmitting signal from your brain so

that you can control everything by just thinking without any action.

Fig 15: Iron Man

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13. CONCLUSION

The exoskeleton is an electromechanical structure worn by operator and matching the

shape and functions of human body. It is able to augment the ability of human limb

and/or to treat muscles, joints, or skeletal parts which are weak ineffective or injured

because of a disease or a neurological condition. Moreover, it merges the machine power

and the human intelligence in order to enhance the intelligence of the machine and to

power the operator. The exoskeleton works mechanically in parallel with human body

and can be actuated passively and or actively.

One of the largest problems facing designers of powered exoskeletons is the supply.

There are currently few power sources of sufficient energy density to sustain a full body

powered exoskeleton for more than a few hours. Non-rechargeable primary cells tend to

have more energy density and store it longer than rechargeable secondary cells, but then

replacement cells must be transported into the field for use when the primary cells are

depleted, of which may be a special and uncommon type. Rechargeable cells can be

reused but may require transporting a charging system into the field, which either must

recharge rapidly or the depleted cells need to be able to be swapped out in the field, to be

replaced with cells that have been slowly charging. Another important limitation is that it

is required to design uniquely for a patient so that all sensors perfectly suited his/her body

dimensions. Currently the exoskeleton suits are highly expensive.

The Cost of the Product is higher To Common People. Bulk Manufacturing Is Not

Possible Due Different Dimension of People A Different Disorders. . It Is Difficult For

An Exoskeleton To Exactly Match The Motions Of This Ball Joint Using A Series Of

External Single-Axis Hinge Points, Limiting Flexibility Of The Wearer. So By Short

Period We Can See The Real Iron Man.

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14. REFERENCES

1. Active Exoskeleton Control Systems: State of the Art - Khairul Anam a,b , Adel Ali

Al-Jumaily

2. Design and development of a hand exoskeleton for Rehabilitation following stroke-

Md Akhlaquor Rahman a , Adel Al-Jumaily

3. Development of a 3DOF mobile exoskeleton robot for human upper-limb motion

assist - Kazuo Kiguchi , Mohammad Habibur Rahman, Makoto Sasaki, Kenbu

Teramoto.

4. Acceptability of robotic technology in neuro-rehabilitation: Preliminary results on

chronic stroke patients - Stefano Mazzoleni , Giuseppe Turchetti , Ilaria Palla.

5. Walk again project becomes a reality S Thash.

6. Exoskeleton robots for upper-limb rehabilitation: State of the art and future prospects

- Ho Shing Lo, Sheng Quan Xie.

7. Design of Human Exo-Skeleton Suit for Rehabilitation of HemiplegicPeople Shah

Mihir Rajesh