| A prosthetic hand, as a substitute for a human hand, plays an important role in the daily life of the disabled. It has been the interest for domestic and foreign researchers to make a prosthetic hand more close to a human hand. To improve anthropomorphism and the grasp stability of a prosthetic hand, simulating the grasps of a human hand and the slip prevention during the grasps were studied based on the design of the electrical and control system.In this paper, a modular and hierarchical electrical control system was designed including hardware design and software design. Using rigid-flex printed circuit board(PCB) ensured electrical control system integrated in the finger and the palm of the prosthetic hand. The system can realize the real-time acquisition and processing of the position, the force and the tactile sensor signal with maximum 9channels, the real-time communication with the upper computer and the driving control for each finger.The anthropomorphism of a prosthetic hand is a concern for amputees including shape, weight and especially the kinematic similarity to the human hand. According to the research of grasp taxonomy, 5 most commonly used postures in life were selected. By analyzing and processing of the joint angles collected in the experiment,the characteristics of each grasping posture were summarized and mapped to the control of the prosthetic hand grasping.During the grasps, a human hand could identify the status by the tactile feedback and make adjustments to avoid slipping when the grasping force is insufficient, which is also significant for a prosthetic hand. The tactile outputs were analyzed by Haar wavelet when the slips occurred. According to the analysis results,a method of slip detection and a control strategy based on this method was put forward. Experiments on the prosthetic hand showed that the method and the control strategy can significantly improve the grabbing performance of the prosthetic hand. |
PDF Full Text Request