摘要
机器人足踝处采取柔性设计可以降低在步行过程中受到地面的着地冲击力的影响,但柔性环节不仅升高了控制系统的阶数,且易引起系统内部振荡,稳定时间增长,不满足控制过程中快速性和稳定性的要求。针对弹簧-套索传动的机器人柔性踝关节,采用奇异摄动理论对其进行降阶简化处理,根据末端角度误差分别采用快、慢变控制器进行切换控制。其中,慢变控制器采用基于比例切换的滑模控制器,使末端快速稳定地到达期望位置,快变控制器采用状态反馈控制器,使得弹簧形变量迅速收敛至零。最后,通过Simulink仿真和样机实验将切换控制与单一采用PID控制或者滑模控制进行对比,实验结果表明,虽然三种控制器均满足快速性的要求,但只有切换控制可以保证多步位置控制时末端的稳定性,达到完整的控制目标要求。
The flexible ankle of the robot can reduce the impact of the ground force during walking. However, the flexible link not only increases the order of the control system, but also causes the internal oscillation of the system easily and increases the stability time, which can’t satisfy the requirement of the rapidity and stability during the process of control. In this paper, the flexible ankle joint of the robot adopts a spring-lasso transmission method. On the basis of the singular perturbation theory, the order of the system is reduced. As a result, the system is more concise. According to the terminal angle error, the fast and slow controllers are both used for switching control. Herein, a sliding mode controller based on proportional switching is used in the slow controller which makes the terminal of the joint reach the desired position quickly and stably. The fast controller uses the state feedback controller to make the variable of spring converge to zero rapidly. Finally, the switching control is compared with the single PID control and the sliding mode control through Simulink simulation and prototype experiment. The experimental results show that although the three controllers all meet the need of rapidity, only the switching control can guarantee the stability of the terminal during multiple position controls, which meets the requirements of complete control objectives.
作者
窦昆鸿
潘晟
罗翔
DOU Kunhong;PAN Sheng;LUO Xiang(School of Mechanical Engineering,Southeast University,Nanjing 211189)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第13期81-88,共8页
Journal of Mechanical Engineering
基金
国家自然科学基金(51375085)资助项目。
关键词
柔性关节
奇异摄动
滑模控制
模型降阶
切换控制
flexible joint
singular perturbation
sliding mode control
model order reduction
switching control
