未知崎岖地形下四足机器人复合抗扰柔顺控制

Compound Anti-interference Compliant Control for Quadruped Robot Under Unknown Rugged Terrain

为使四足机器人能够在未知崎岖地形中以对角(Trot)步态柔顺且稳定地行走,提出了一种复合抗扰柔顺控制策略。首先,四足机器人的机身和支撑相采用内外环分层控制策略,外环采用全局快速终端滑模控制器来控制机身的位姿,以使机身位姿快速精确地收敛到平衡状态,并通过设计非线性干扰观测器来消除系统不确定性和外界扰动,以进一步提高系统的鲁棒性;其次,内环采用基于力的PD控制器,以使支撑相的足端接触力能够跟踪滑模控制器所需的期望力,实现足端与地面的软接触,减少对机器人的冲击;同时,摆动相采用具有相同主动柔顺性的阻抗控制器;最后,采用MATLAB/Simulink进行了对比仿真实验,结果表明在所提控制策略下,四足机器人在未知崎岖地形中行走具有良好的鲁棒性和柔顺性。

To realize the compliant and stable locomotion of a quadruped robot with Trot gait in unknown rough terrain,a composite disturbance rejection compliant control strategy is proposed.Firstly,the torso and support phase of the quadruped robot adopts a layered control strategy of inner and outer loops,and the outer loop adopts a global fast terminal sliding mode controller to control the pose and position of the torso so that the pose and position of the torso quickly and accurately converge to the equilibrium state.To further improve the robustness of the system,the nonlinear disturbance observer is designed to eliminate system uncertainties and external disturbances;secondly,a force-based PD controller is used in the inner ring to make the foot contact force of the support phase track the expected force required by the sliding mode controller to achieve soft contact between the foot and the ground,to reduce the impact on the robot.Meanwhile,an impedance controller with the same active compliance is used for the oscillating phase.Finally,MATLAB/Simulink is used to carry out comparative simulation experiments,and the results show that the quadruped robot has good robustness and flexibility under the control strategy in the unknown rugged terrain.