Progress in the biomechatronic design and control of a hand prosthesis

A five-fingered, multi-sensory biomechatronic hand with sEMG interface is presented. The cambered palm is specially designed to enhance the stability while grasping. The location of the thumb is designed by maximizing interaction area between the thumb and other fingers. The opposite thumb could grasp along a cone surface, while maintaining its function. By taken the advantage of coupling linkage mechanism, each finger with three phalanges could fulfill flexion-extension movement independently. Besides, each finger is equipped with torque and position sensors. Thus, the cosmetics and dexterity are improved remarkably compared to conventional prosthesis. The hardware architecture is divided into control system and EMG signal processing system. Moreover, a novel two-stage decision strategy combing the position-based impedance control scheme is implemented to realize the real-time sEMG control of the hand. According to the grasp experiment results, the hand can accomplish several grasp modes stably; the success rate of 10 modes is up to 90%.