Research on Stability Control Method of Parallel Six-wheel-legged Robot

doi:10.3901/JME.2021.21.034

Abstract

Abstract: The stability control of the wheel-legged robot passing on uneven roads is the main challenge to improve the stability of the movement and reduce system energy consumption and increase the accuracy of positioning and mapping. Aiming at the problems of hanging legs, body shaking, and tilting of the body of a six-wheel-legged robot, a body stability control framework is proposed which integrates the leg force controller, the attitude controller, and the height controller. Firstly, the leg force controller uses an impedance control algorithm to limit the sudden disturbance of the force due to terrain changes; the attitude controller decouples the tilt angle of the body and changes the length of each leg to compensate for the offset of the body; The height controller adaptively adjusts the height of the center of the body according to the length of each leg to ensure that the leg actuator has enough space for movement. Furthermore, using the idea of the cascade controller to unify the three control targets into force tracking control to solve the problem of coupling of three controllers and restrain external disturbances. Finally, experimental results show that BIT-NAZA can move in an uneven road with a pitch and roll angle of -0.7° to 0.7° under the speeds of up to 0.6 m/s, as well as the foot contact force maintained near the expected force, and the height of the robot is adaptively adjusted with the undulation of the ground, which ensures the motion stability of the robot.

Key words: wheel-legged robot, stability control, cascade control

CLC Number:

TP242

LEI Tao, XU Kang, WANG Shoukun, WANG Junzheng, LIU Dongchen, LIU Pengtao. Research on Stability Control Method of Parallel Six-wheel-legged Robot[J]. Journal of Mechanical Engineering, 2021, 57(21): 34-44.

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