Design Development and Control of Prosthetic leg

Project Title

Design Development and Control of Prosthetic leg

Project Area of Specialization RoboticsProject Summary

The human history has been accompanied by accidental trauma, war and congenital anomalies. Consequently, amputation and deformity have been dealt with one way or the

other throughout these ages. Our motivation behind this project is the fact that in Pakistan, there are millions of people living with limb loss and mostly require prosthetic leg every year. Our project aims to provide prostheses for above-knee amputees in which the important part is to acquire EMG signals from the calf muscles of the healthy leg and analyze them to provide the control signals to actuate the knee joint of the prosthetic leg using a microcontroller.

Designing the EMG based prosthetic leg that will be cost effective and will have the maximum degree of freedom is the main theme of this project. We will be using real-time EMG signals from leg upper limb muscles to detect the signals and process them to drive motor in artificial knee with controller. Then we will design the prosthetic leg structure on CAD software. Afterwards we will use 3d printer for printing the structure and implement the robust feedback control system on it.

Residual limb pain is when the area around your prosthesis hurts, due to limb shrinkage. This has an effect on how your prosthesis fits, and can cause a prosthetic leg that once fit very well to start causing you pain and trouble. So, we will make it more flexible and more comfortable of the user for longer use.

As a result, we will develop an EMG controlled prosthetic leg on the principles above discussed. It will be cost effective and maximum Degree of Freedom having robust feedback control system.

Project Objectives

Key objectives of our project are given below:

1-Main purpose of this project is to serve the humanity. As an Engineer, its our responsibility to provide solutions to amputee people to maximize their potential.

2-To Design a robust feedback control system that voluntary detects signals from calf muscles, send controller to activate knee rotation though motor, gears and damper.

3-To design compact and usable artificial leg.

4-To develop cost effective prosthetic leg.

5-To develop artificial leg that moves similar to a real human leg.

6-To make it water resistant and flexible to wear.

Project Implementation Method

The project implementation will be carried out in the following steps:

Data Acquisition:

We will first collect EMG signal from residual limb of amputee person. Basically, Electromyography (EMG) is a physiological signal that is produced due to the electrical activity of muscles. In this project, an artificial leg which is controlled using the EMG signals that are acquired from the residual limb of the user with the help of surface electrodes attached to the user’s skin, which avoids bulky interface sensors.

Then comes to amplification of extracted signal because EMG signals has low voltages. So, we will use amplifier that receives signals from electrodes, then takes the difference between two electrodes and amplify it.

Preprocessing:

In preprocessing we will implement digital filtering because a lots of unwanted signals (noise) present in the EMG signal obtained from the electrodes. These filters will help to remove such unwanted noise signals.

Processing (feature extraction & classification):
After preprocessing stage, the absolute value of the EMG signal is calculated so that the envelope of the signal can be determined, which can then be used with a threshold to decide whether to open or close the prosthesis. And also classify the EMG signals into Extensor and Flexor signals for the movement of knee.

Control system:

A robust feedback control system will be designed that will detect the classified signal and applies an algorithm that activates the knee motor.

Hardware Design:

At the end, we will do 3D printing for it structure design. And then we will connect all the parts (motors, damper, controller, battery etc). Lastly, we will have a final product to display.

Benefits of the Project

The lack of access to prosthetics prevents people with limb loss from living productive lives, leads to poor rehabilitation outcomes, and places amputees at risk for dangerous and costly secondary conditions such as obesity, cardiovascular disease and additional amputation. Hence, when a leg or other limb is amputated/lost, a prosthetic device, or prosthesis, can play an important role in rehabilitation. It also provides improvement of mobility, ability to manage daily activities and means to stay independent. Likewise, provide an affordable solution of prosthetic limb for the third world country and least dependency on imported prosthesis.

Technical Details of Final Deliverable

Technically our project has two parts:

Firstly, we will use of biomedical sensors i.e. EMG electrode to acquire the data from the leg limb above knee. And then classify the extensor and flexor signals in real-time from EMG signals to control the motor.

Secondly, will use dampers, motors, gears and Controllers to control the whole system.

In our proposed project, Robust feedback control system will be designed that detects external disturbance and tackles uncertainties in order to negate the effect of any system disturbance.         

Final Deliverable of the Project Hardware SystemType of Industry Medical Technologies RoboticsSustainable Development Goals Good Health and Well-Being for PeopleRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	78500
Leg frame	Equipment	1	3100	3100
Servo Motors	Equipment	2	1200	2400
EMG Module	Equipment	2	5800	11600
Electronic Speed Controllers	Equipment	2	1200	2400
Gears	Equipment	2	550	1100
Dampers	Equipment	2	5000	10000
LiPo Battery 2200mah	Equipment	3	2500	7500
lipo battery charger	Equipment	2	2000	4000
Arduino	Equipment	2	2500	5000
Motor driver	Equipment	2	750	1500
3D Printing	Equipment	1	20000	20000
Spring	Equipment	2	700	1400
Stationary and printputs	Miscellaneous	1	4000	4000
others	Miscellaneous	1	4500	4500