DESIGN AND DEVELOPMENT OF BIONIC ANKLE-FOOT PROSTHESIS FOR LOWER LIMB AMPUTEES

Project Title

DESIGN AND DEVELOPMENT OF BIONIC ANKLE-FOOT PROSTHESIS FOR LOWER LIMB AMPUTEES

Project Area of Specialization Mechatronics EngineeringProject Summary

Recent time has led the Mechatronics Engineering to a new world that offers a wide range of exploration and a vast improvement of margin; which is rehabilitation. Every passing year, Due to different mishaps, many people suffer from different walking disabilities, most of such scenarios lead to amputation. Lower limb amputation due to traumatic accidents, vascular complications, diabetic ulcers or neoplastic lesions accounts is a common practice in developing countries. A prosthetic limb is an alternative solution provided to keep the specimen mobile. This project is all about a working model of a bionic prosthetic foot as a feasible and economical solution for walking aid. Our slogan is to make a “simple mechanism with the simplest controlling strategy”. This prosthetic foot will be working upon the output of two force and proximity sensors with direct interfacing of actuator while keeping the system completely autonomous. Despite making a prototype, we are fabricating a real-time working model according to a patient (Having Lower Limb Amputation) provided by the “Comprehensive Rehabilitation Center”. After the successful simulation of mechanical design on SolidWorks currently, we are working in the fabrication phase which is almost 80% done. The model will not only be equipped with the latest in the market technology but we are also trying to make it more economical for better feasibility and availability to the common man.

Project Objectives

The objectives of the project cover the development of a prosthetic foot from the design to the fabrication, which can be controlled by the proximity and force sensors. For the designing phase of the under-consideration prosthetic walking aid, the simulation will be carried out by using Solid Works and MATLAB accordingly. The proximity sensors will be placed on the lower limb which will serve as the input module to the actuator. The actuator will be fully autonomous activated by the proximity sensors and force sensors in the gait cycle.

• Main Objectives

1. To make it simple so that people can easily be carried out in their daily life.
2. To introduce the bionic Prosthetic technology in Pakistan.
3. To make it affordable for poor people.

• Research Objectives

1. To develop an efficient system which can be controlled with various type of sensors
2. To implement a robust controlling strategy
3. To identify the end-user requirement in Pakistan

• Academic Objectives

1. Development of a working model 
2. Write up of research article

• Commercial Objectives

1. High tech electronic leg is very popular in Europe and is available at 5,000$-50,000$ and if we will get success in making it under 500$-550$ then it will definitely impart a huge impact on the market because we can not only save a huge foreign exchange but also export it to other developing countries where patients cannot pay such huge sums of money.

Project Implementation Method

The below table show the implementation plane for our project.

Benefits of the Project

When a foot or other extremity is lost, a prosthetic device, or prosthesis, can play an important role in walking. For many people, an artificial limb can improve mobility and the ability to manage daily activities, as well as provide the means to stay independent. This product helps the handicap in their daily activities by replicating the natural walk of the foot.

1. This will help in introducing the bionic limbs technology ln Pakistan
2. Helps the poor people who cannot afford costly bionic limbs
3. Improved quality of life
4. Ease of wearing and quick removal
5. The patient can walk to a longer distance 
6. A sense of the artificial limb belonging to the body

• Impact on Society

A large part of the handicapped population is living without proper facilities and is isolated by the mainstream because they cannot pay high prices of artificial limbs, while only the rich can buy the modern artificial limbs. And to the bionic one, it seems to be impossible for people living in a country like Pakistan. In western countries it’s cost ranges from 10,000$ to 50,000$. Not only the microprocessors, motors, and other electronic equipment are at a high cost but also materials used in the manufacturing of artificial limbs are costly, taxes and duty over the import of these materials add to the end price of these limbs. Classified as space-age materials owing to their toughness, reliability, and lightweight, costly materials used in manufacturing artificial limbs include fiberglass, high-grade alloy aluminum, titanium, stainless steel, and carbon fiber.

By considering all these facts our main objective is to make it simple, reliable and most importantly cost-efficient. Developing countries such as Pakistan, people with lower limb amputation suffer greatly in terms of mobility. The model upon completion will serve as a cost-effective solution to such people and restore the patients with the function of mobility.

Technical Details of Final Deliverable

Our final deliverable main categories into two major categories.

Mechanical Design

The most important part of the project is mechanical design. Our mechanical design starts with the sockets that wear the patient. The inner and outer sockets produce by 3D printing. The next thing is Pylon Rod that makes the physical connection between the sockets and foot mechanism. The foot mechanism consists of four links that connect the upper frame and base of the bionic foot. The base bounds with the shoe to replicate the motion of the foot. The figure also shows the motor with the threaded pin passes through the cylinder that holds between the two links. This motor rotation will move the screw forward and backward which leads to the rotational movement of the foot due to the adjustment of the links. The above-explained design is shown below.

Controlling Strategy

The second deliverable is all about how to control and replicate the motion of foot according to the other leg movement. Our primary objective is to make it simple, easy to use and more importantly cost-efficient. Our model consists of three sensors that will be two force sensors and one proximity sensor. The two force sensors are placed under the foot that gives information about the position of the foot. It works on the principle of Heel Strike Toe off as shown in the figure below.

In the stance phase when the heel strikes the ground first force sensor gives the value that fed to the microcontroller after passing through the instrumentation circuit. The microcontroller then rotates in motor anticlockwise to make the 20 Degree (Dorsiflexion) rotation of the foot. After this proximity sensor senses, the movement of another leg that passes through and the rest of the movement that is 40 Degree (Plantar Flexion) takes place. Similarly, in the swing phase when toe-off then both force sensors will be zero then the microcontroller moves the motor in a clockwise direction 40 Degree and the rest of the 20 Degree turn after proximity sensor sense the motion of the other leg. The below figure will help to illustrate the phenomena.

Final Deliverable of the Project Hardware SystemCore Industry MedicalOther Industries Education , IT , Others , Health Core Technology Internet of Things (IoT)Other Technologies Robotics, Wearables and Implantables, OthersSustainable Development Goals Good Health and Well-Being for People, Reduced Inequality, Responsible Consumption and Production, Life on LandRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	79690
3D Printing of Sockets	Equipment	2	2690	5380
Pylon Rod	Equipment	1	2840	2840
Material Purchasing and CNC Cutting of Frames and Links	Equipment	1	28000	28000
Foot Material & Machining	Equipment	1	2975	2975
Arduino Uno	Equipment	1	970	970
High Torque Dc Encoded Motor	Equipment	1	17845	17845
Proximity Sensor	Equipment	1	2860	2860
Force Sensors	Equipment	2	1360	2720
Motor Driver	Equipment	1	750	750
Instrumentation Circuitry Components	Equipment	1	2430	2430
24v Lipo Battery	Equipment	1	2920	2920
Miscellaneous	Miscellaneous	1	10000	10000