A study of implantable power assist and transhumeral robotic prostheses

Abstract

Few decades ago, usually robots were considered as tools in a manufacturing environment to perform welding, spray painting, drilling, material handling or assembling operations.However, recent advances in robotics technology bring a lot of benefit not only in industrial sector, but also in several other sectors.Using the robotics technology in the present world can be found in the manufacturing industry, military application, space exploration, transportation, amusement, rescue operation, household, medical, hazardous environment application etc.In order to acquire unprecedented control and precision, robotics is being introduced to medical application.The continuous advancement of artificial intelligence and robotics technology enables the robots to work in an autonomous manner or in combination with the human in the field of medical applications.Currently robots are used to help or to take care of the patients as a functional substitute of the nurses, as an assistant for the medical surgeon to carry out complex surgery, as a power assist and rehabilitation device for the physically disabled persons, etc.In this thesis, the design and control strategy of implantable power assist and transhumeral robotic prostheses is described which are expected to play a vital role among the physically disabled and above-elbow amputees society, respectively, in near future.In order to help the physical activities of elderly or physically disabled persons, a new concept of implantable power assist prosthesis is proposed in this thesis that is supposed to assist the human daily life motion from inside of the human body.This thesis presents an implantable 2 degree of freedom (DOF) power assist prosthesis (i.e., inner skeleton robot) that is designed to assist human elbow flexion-extension motion and forearm supination-pronation motion in daily life activities.In this research a prototype of inner skeleton robot is developed that is supposed to assist the motion from inside of the body and act as an actuated artificial joint.The proposed system is controlled based on the activation patterns of the electromyogram (EMG) signals of II the user muscles by applying a fuzzy-neuro control method.A joint actuator with an angular position sensor is designed for the inner skeleton robot and a T-Mechanism is proposed to keep the bone arrangement similar to the normal human articulation after the elbow arthroplasty.The effectiveness of the proposed system has been evaluated through experiments.The design and control strategy of transhumeral prosthesis for above-elbow amputees is also proposed in this thesis.Transhumeral prosthesis, which is used to compensate for the lost functions of above-elbow (AE) amputees absent arm, is also termed as above-elbow prosthesis or prosthetic arm.Recent progress in biomechatronics technology has facilitated increased mobility of AE amputees in performing daily life activities.However, presently available commercial prosthetic arms have failed to gain wide acceptance among AE amputees due to the discrepancy between their expectations and reality.The main factors causing a lack of interest in presently available prosthetic arms include low functionality and poor controllability.Currently available externally powered AE prosthetic arms provide two or three DOF motions, which are insufficient to generate natural human-like arm motion.In order to improve the quality of life and to increase the mobility of AE amputees in their daily life activities, a 5 DOF AE prosthetic arm is developed in this research work.Control of a multi degree of freedom (DOF) prosthetic arm also remains as a challenging problem.As a result, a new controller strategy for the control of the designed 5 DOF prosthesis is also proposed in this thesis.The proposed prosthesis is supposed to be controlled by using a combination of the electromyogram (EMG) signals and the joint kinematics of the user's stump arm.A fuzzy rule based controller that uses EMG signals