A low-cost system to control prehension force of a custom-made myoelectric hand prosthesis

• Published in: Research on biomedical engineering Vol. 36; no. 3; pp. 237 - 247
• Main Authors: Prakash, Alok, Sharma, Shiru
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.09.2020
• Subjects: Biomaterials; Biomedical Engineering and Bioengineering; Biomedical Engineering/Biotechnology; Engineering; Original Article; Force sensor; Prehension force; Electromyography; Myoelectric prosthesis; Position control
• ISSN: 2446-4732; 2446-4740
• DOI: 10.1007/s42600-020-00064-w

Purpose In order to achieve stable and dexterous grasping of objects, prehension force control is quite a significant parameter for prosthetic hands. Commercially available hands such as bebionic, i-limb quantum and Michelangelo offer the precise grasping capability to perform activities of daily living (ADLs). However, the cost of such hands is too expensive for amputees residing in low-income countries. Methods This paper introduces a low-cost, simple and efficient system for controlling the prehension force of a self-designed myoelectric prosthetic hand. A hand prototype was developed employing 3D printing technology and an intrinsic actuation approach. The hand fingers were equipped with a pre-calibrated force sensor for the online estimation of the grasp force. A closed-loop proportional-derivative (PD) based position control system was designed considering actuator as plant, electromyography (EMG) as a reference and grasp force as a feedback signal. Results The results showed highly improved parameters, i.e. overshoot, offset and settling time of the proposed system than a simple open-loop system. These parameters guarantee faster closing of hand fingers and the production of accurate prehension force during finger-object interaction. Conclusion Further, the myoelectric hand with a developed control scheme was successfully tested on five different transradial amputees for performing precise and faster grasping of different shaped objects.