Development of Tendon Based Dexterous Robot Hand

Dexterous robot hand development is a very challenging and interesting research topic. A dexterous robot hand may serve as a prosthesis hand for disabled patients or to serve as a gripping device for robotic arms. In most of previous studies, the dexterous robot hands are developed based on the directed gear train controls and tendon wired controls. The directed gear train control based design (Lin et al., 1996; Namiki et al., 2003) directly coupled the gear train in the finger module mechanisms. In such a configuration, the weight of the dexterous robot hand is quite heavy because of using numerous gear parts and motors. At the same time, the mechanical design and the assembly of the directed gear train dexterous robot hand are much complicated. Meanwhile, the heats resulted from high reduction of gear trains as well as the high speed rotation of motors are also challenging issues of directed gear train based dexterous robot hands. Consequently, the weights and heats are major concerns when applying this configuration to the prosthesis hand for amputees. On the other hands, the tendon wire control based dexterous robot hand allocates the gear trains and motors at a distance location (Jacobsen et al., 1986; Kyriakopoulos et al., 1997; Challoo et al, 1994). In this manner, the weights and heats produced from motors and gear trains are resolved when compared to the directed gear train based configuration. Nevertheless, the non-rigid characteristics and frictions of the tendon wires are also important to the precise control of a dexterous robot hands. In this chapter, a dexterous robot hand with tendon wired control is proposed to perform the characteristics of compact size and low weight. According to this purpose, the dexterous robot hand size is defined as the hand size of a twenties male. In order to reduce the weight of the dexterous robot hand, the ABS engineering plastic material is used in this study. Additionally, to emulate the hand motions of a human, the dexterous robot hand is designed as a five-finger mechanical structure. Consequently, the proposed dexterous robot hand is composed of 16 joint motions. To reduce the control complexity, 12 active joints are independently controlled; and the remaining four joints are manipulated depending on four corresponding active joints. At the same time, five FSR pressure sensors are attached on the tips of all fingers to detect external forces applied on the corresponding fingers. Therefore, the robot hand is capable of 12