摘要
轮腿式机器人在非结构化路面运动时,机身平稳性控制对于提高运动平稳性、降低系统能耗、提高定位与建图精度等具有重要意义。针对并联式六轮腿机器人在通过不规则地形时足端悬空、姿态倾斜、机身晃动等问题,提出一种融合足端力控制器、姿态控制器及重心高度控制器的机身平稳性控制框架。其中,足端力控制器通过阻抗控制算法抑制机器人足端受力因地形变化带来的突变扰动;机身姿态控制器对机身倾斜角进行解耦,并控制各腿的长度补偿机身的偏移量;重心高度控制器根据各腿的伸长量自适应地调节机身高度,保证腿部执行机构具有足够的运动空间。针对三种控制器相互耦合、对外部扰动抑制效果不佳等问题,利用串级控制的思想将三种控制目标统一为力跟踪控制,降低机身振荡的风险。在并联式六轮腿机器人上进行了实验验证,结果表明所提出的控制算法框架能有效抑制外部地形扰动,当机器人以大约0.6 m/s的速度前进时,机身的俯仰角及横滚角保持在-0.7°~0.7°范围内,足端接触力维持在期望力附近,且机身重心高度随地面起伏自适应地调整,确保了机器人的运动平稳性。
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.
作者
雷涛
徐康
汪首坤
王军政
刘冬琛
刘鹏涛
LEI Tao;XU Kang;WANG Shoukun;WANG Junzheng;LIU Dongchen;LIU Pengtao(Key Laboratory of Complex System Intelligent Control and Decision,Beijing Institute of Technology,Beijing 100081;Key Laboratory of Servo Motion System and Control,Beijing Institute of Technology,Beijing 100081)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2021年第21期34-44,共11页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(61773060)。
关键词
轮腿机器人
平稳性控制
串级控制
wheel-legged robot
stability control
cascade control
