Combined active and passive adaptive variable admittance compliant control for space robotic manipulators

This paper develops a combined active and passive adaptive variable admittance compliant control algorithm for space robotic manipulators. In fact, the assembly task for space robots requires compliance and precision while ensuring avoidance of any occurrences of rigid collision throughout the process. Therefore, we design a new combined active and passive variable admittance control structure combined with the following three parts to meet these acquirements. Firstly, we develop an active variable admittance algorithm to facilitate the space robot rapid movement, enabling it to achieve higher speeds while maintaining compliance. Then, to mitigate the occurrence of unforeseen rigid collisions during the robot motion, we devise a passive variable admittance control algorithm, which aims to minimize the impact of collision events and ensure the robot safe operation. Furthermore, by employing the Lyapunov theory, a new active adaptive variable admittance control algorithm is presented for robot constant force output. Consequently, through contrast experiments, we demonstrate the effectiveness and enhanced performance of the proposed algorithm.