Research on Impedance Control Method of Legged Robot with Gait and Load Adaptive Capability

Abstract

Due to the characteristics of discontinuous support and flexible manoeuvring characteristics, the legged robot is expected to play an important role in military, rescue and transportation tasks. The high dynamic characteristics of movement and the high uncertainty of the environment and load make the robot's compliant control particularly important, especially when facing complex environments and rough terrain. Impedance control is an effective method to solve this problem. The traditional impedance control structure has an upper limit on the response time of the system, and parameter setting generally depends on experience. This paper presents an improved impedance control method for legged robots. We have improved the structure by introducing force changes and decomposed the controller into force-position conversion factors and impedance subsystems, which can greatly shorten the response time of the system. We also improved the method of parameter setting. Simultaneously, we propose an optimization target and optimization method for impedance control parameters, aiming to improve the adaptability of the legged robot to the asynchronous state and load. We have realized the impedance control of the adaptive parameters on the platform of both single robot and the quadruped robot, and the experiment verifies the effectiveness of the method.