Tip force tracking control based on the tendon-sheath transmission model and 3D reconstruction of a long slender rescue robot

Tendon-sheath actuated mechanism is widely adopted in many applications such as robot hands and surgical devices due to its small size, simple structure and light weight. However, there exist a lot of factors including the compliance and friction between the tendon and sheath which may contribute to the nonlinearity of the tendon-sheath system. In addition, the absence of sensors at distal end also sets a limit to the application of tendon-sheath. In this paper, a tendon-sheath-driven robot for searching and rescuing is introduced and the transmission models of tendon-sheath system are proposed. 3D reconstruction of tendon-sheath system is utilized for the identification of parameters involved in the model. Two methods are presented according to whether the sensor information at distal end can be obtained or not. In order to make up for the nonlinearity of the system, the sliding control method is adopted. Despite of the lack of feedback information, a combination of inverse compensation and sliding mode control is put forward. Furthermore, a set of experiments are carried out in order to validate our proposed models and methods.