Exoskeleton based Hand Rehabilitation for Post Stroke Motor Recovery

Since past three centuries the advancement of science and technology has enabled us to combat many diseases in much better ways and has helped us eradicate many plagues altogether. One of the most important diseases or rather malfunctions of the human body is a disability through strokes. Eve

Project Title

Exoskeleton based Hand Rehabilitation for Post Stroke Motor Recovery

Project Area of Specialization

Wearables and Implantable

Project Summary

Since past three centuries the advancement of science and technology has enabled us to combat many diseases in much better ways and has helped us eradicate many plagues altogether. One of the most important diseases or rather malfunctions of the human body is a disability through strokes.

Every year around 15 million experience a form stroke. In many cases it kills the patient, but those who are lucky enough to survive, aren’t lucky to get away it easily. Unfortunately, strokes cause various disabilities in almost every part of the human body. 

Researches show that majority of those who experience a stroke can be rehabilitated either partially or fully. Although there are many mechanical devices used for rehabilitation of stroke patients, they do not have a set of dynamic parameters matching the actual movements of the human muscles. This is where modern mechatronic and control system come into play.

The idea is to help these patients get rehabilitated in an efficient way by training their disabled hands (wrists) using an exoskeleton. The exoskeleton’s function is to train the disabled wrists with the exact dynamics and of natural muscle movements in a normal human hand.

This exoskeleton will be a wearable device which will be used for training of hand wrist and fingers to fasten the recovery of the post-stroke patients. Each session can last between 40 minutes to an hour for a period of 1 to 3 months.

Numerous studies have shown that similar devices have fastened the rehabilitation process by months and even years.

Project Objectives

The objective of the project is to rehabilitate the paralyzed hand from wrist down by stimulating movement in the hand using an exoskeleton. When the hand moves in the brain’s intended directions, this phenomenon amplifies the muscles impulses with the passage of time. After a certain amount of time, the signals become strong enough to independently induce movement in the hand.

This device not only will help the patients recover faster in a more efficient manner, it will also make sure that after the recovery of the nervous tissues, each signal produces a movement exactly like the one produced by a healthy person. It will also make sure that after the recovery, each muscle can function till its physical and biological limits.

Project Implementation Method

The project starts from the study of literature required to understand human hand anatomy and EMG signals as well as their relation to the mechanism which produce desired hand movements in a healthy person. After which, it is compared to the signal acquired from the patient’s hand, the error signal produced will be used to actuate brain’s intended movements in the hand, the exoskeleton will move in those directions.

The signal acquisition will take place using Myo sensors around the half-way from elbow joints to the wrist joint. This signal will be converted to a digital form and then a central controller, most likely a Field Programmable Gate Array (FPGA) or a development board such as Raspberry Pi, will be used to generate a series of signals corresponding to the intended movement of the hand. These signals will be fed to the microcontroller or any development boards (Arduino), which will be responsible for the actual (physical) movement of the exoskeleton using servo motors.

The movement will most likely correspond to a proportional multiple of the error signal in a feedback loop control system. Each movement of the exoskeleton will help the hand parts such as DIP, PIP and MCP joints, move in the linear as well as angular direction of the intended signal. Such movements, over a certain amount of time, will result in rehabilitation of the hand as the recovery of the nerves progress.

Benefits of the Project

This project will improve the clinical intervention, restore the patient’s mobility and will lead to better rehabilitation design for stroke patients.

This device can provide the health benefits of a similar device produced by advanced prosthetic device companies at a fraction of the cost. This will enhance the health services to stroke patients all around the world especially poor nations where majority of stroke survivors cannot attend physiotherapy session or buy expensive rehabilitation equipment.

As this device will be a portable one, it can be used for training of patients at the comfort of their households. Apart from rehabilitation, this device can be used as assistive device for the people with permanent hand disabilities helping them in their day to day life. This feature of the device can make it an essential part of patients’ lives.

Technical Details of Final Deliverable

Electromyography sensor

EMG Muscle Sensor Module V3.0 With Cable and Electrodes will measure the filtered and rectified electrical activity of a muscle; outputting 0-Vs Volts depending the amount of activity in the selected muscle, where Vs signifies the voltage of the power source. Power supply voltage: min. +-3.5V.

3D printed module

The main part of our device will an exoskeleton covering the hand from mid-point of the forearm to the tip of the finger. This exoskeleton will be modelled and printed using 3D printing technology which will make it more flexible and affordable. 

The initial design will be constructed using autoCAD and then later one the final version will be created on SolidWorks. 

Servo Motor

Servo engine is a kind of motor that can move or pivot its shaft in a particular point with high exactness control of precise or straight position, speed, and quickening. This is really a DC Motor whose speed is gradually brought down by the gears. Servo Motor is Also called Servos. The shaft of servos generally doesn't move freely around like a DC engine, Servos are constrained by sending an electrical beat of variable width or heartbeat width regulation (PWM), through the control wire. Their turn is restricted between the fixed points. The engine is connected with gears for controlling the wheel. As the engine turns, the potentiometer's obstruction changes, and afterward the control circuit manages how much development there is and in which heading additionally with exactly. servo engines don't turn continually. Their pivot is restricted in the middle of the fixed points.

A typical rapid minuscule electric engine doesn't have a lot of force; however, it can turn extremely quick. However, Servos give more force than ordinary high rpm DC engine.

A servo engine comprises of three wires–a dark wire associated with the ground, a white/yellow wire associated with the control unit and a red wire associated with the force supply. 

The servo motor used for this project will have a rating of 15 kg.cm. 

Arduino Mega

As this project requires extremely fast reaction of the actuators, the controller must consume the least amount of time possible on code execution. For this purpose, Arduino Mega is a suitable choice. Not only it possesses enough processing power, it can react must faster than other development boards such as Raspberry Pi. 

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Medical

Other Industries

Manufacturing

Core Technology

Wearables and Implantables

Other Technologies

3D/4D Printing

Sustainable Development Goals

Good Health and Well-Being for People

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com