Research On Control System For 5-DOF Humanoid Prosthetic Hand

The research on multi-DOF (degree of freedom) prosthetic hand is an attentive subject in the fields of robot research recently. This study is not only of great theory and market value, but also plays an important role in improving the living condition of the handicapped and the medical welfare of the whole society. Based on national high technology research and development program"Research on high performance humanoid prosthetic hand"(No. 2009AA043803) and the key program of National Natural Science Foundation of China(NSFC)"Study on humanoid prosthetic hand system and its theory"(No. 50435040), the controller for the new humanoid prosthetic hand whose fingers can be actuated respectively is developed, this paper also develops a wireless sEMG(surface electromyography) sensor, and researches on the impedance control algorithm. Besides, this paper develops the bottom controller for partial hand.Based on the previous prosthetic hands developed by DLR-HIT lab, in combination with experimental results and clinical feedback, we develop the new generation prosthetic hand with five fingers, each finger is individually actuated by a DC brush motor and has 3 active joints, four-bar linkage is used to accomplish coupling of the finger. The prosthetic hand is slightly smaller than adult hand and weighs about 420g.According to analysis of the control function achieved by the prosthetic hand, this paper uses the layered control structure: the top controller uses a DSP to achieve human-computer interaction control; the bottom controller adopts the DSP+CPLD scheme to control the prosthetic hand body. This paper mainly deals with design of the bottom controller, and the motion control module, the sensor processing module are designed. The low power design and integrated mechatronics design is considered during the process.As the EMG control is a main control method for the prosthetic hand, this paper constructs an EMG control system using the wireless sEMG sensors to achieve EMG control. This paper designs a sEMG collection and regulation module, the sEMG processing and wireless transmission module is also designed based on CC2510. The TDMA manner is adopted to achieve point to multipoint communication.At last, the position-based impedance control strategy is studied. This paper designs an inner position control loop for the prosthetic hand, analyzes the stability of the system, Besides, a damping coefficient online-adjusting strategy is adopted to overcome the problems lied in the traditional impedance control with constant damping coefficient.