变负载下机器人液压串联弹性执行器动态位置控制方法  

Dynamic Position Control Method for Hydraulic Series Elastic Actuator of Robot under Variable Load

作　　者：曹学鹏[1,2] 鲁航 朱文锋 钱亚伟[1] 田富元 CAO Xuepeng;LU Hang;ZHU Wenfeng;QIAN Yawei;TIAN Fuyuan(School of Construction Machinery, Institute of Mechatronics, Chang’an University, Xi’an 710064, China;Engineering Research Center of Ministry of Education for Advanced Energy-saving Drive Technology, Chengdu 610031, China)

机构地区：[1]长安大学工程机械学院机电液一体化研究所,西安710064 [2]先进节能驱动技术教育部工程研究中心,成都610031

出　　处：《西安交通大学学报》2022年第4期91-100,共10页Journal of Xi'an Jiaotong University

基　　金：陕西省重点研发计划资助项目(2021ZDLGY09-02);陕西省交通运输厅科研项目(18-16K);先进节能教育部工程中心开放课题(SWEDT-KF201902)。

摘　　要：针对变负载下接触环境刚度不确定时液压驱动机器人末端执行器动态性能差的问题,提出了基于时间-误差绝对值积分控制器(ITAE)的液压串联弹性执行器(SEA)动态位置控制方法。首先,根据液压缸的流量连续性方程和活塞与负载的动力学方程,以负载与活塞的位移、速度及负载压力差作为状态变量,运用状态空间法建立液压SEA的五阶状态空间模型;然后,考虑系统带宽、阻抗和重载工况对串联弹簧刚度的不同要求,确定出串联弹簧刚度范围,兼顾系统的快速响应性和稳定性,对时间与误差的绝对值乘积积分,构建基于ITAE的控制器;最后,采用ITAE控制器实现变负载下液压SEA动态位置的精确控制。仿真实验结果表明:在纯惯性负载下,ITAE控制器相比基于灰狼优化的PD控制器(GWO-PD控制器),响应速度快12.5%,稳态误差减小93%;在纯惯性-复合负载切换工况下,当串联弹簧刚度变化时,ITAE控制器相比GWO-PD控制器,响应速度快80%,稳态误差减小18%,而GWO-PD控制器在弹簧刚度较小时产生高频振荡,最大振荡为13.83%;当接触环境刚度变化时,ITAE控制器相比GWO-PD控制器,响应速度快81%,稳态误差减小45%。采用ITAE控制,在内、外参数变化时SEA均具有良好控制性能,可满足非结构环境下的应用要求。A dynamic position control method for hydraulic series elastic actuator(SEA)based on integral of time multiplied by absolute error(ITAE)is proposed for solving the problem of poor end actuator dynamic performance of hydraulic-driven robot under variable load and uncertain contact ambient stiffness conditions.First,according to the flow continuity equation of the hydraulic cylinder and the dynamic equation of the piston and the load,the displacement,speed and load pressure difference between the load and the piston are taken as the state variables;the state-space method is used to establish the five-level state-space model of the hydraulic SEA.Then,based on the requirements for series spring stiffness under different system bandwidth,impedance and heavy load conditions,the stiffness range of series spring is determined.Furthermore,considering the rapid response and stability of the system,we have constructed an ITAE-based controller by integrating the absolute values of time and error.Finally,the ITAE controller is used to accurately control the dynamic position of hydraulic SEA under variable load.The simulation result shows that under pure inertia load,the ITAE controller has 12.5%faster response speed and 93%lower steady-state error than the Grey wolf optimized PD controller(GWO-PD);Under the pure inertia-composite load switching condition:when the series spring stiffness changes,the ITAE controller has 80%faster response speed and 18%lower steady-state error than the GWO-PD controller(however,the GWO-PD controller produces high frequency oscillation when the spring stiffness is small,and the maximum oscillation value is 13.83%);when the ambient stiffness changes,the ITAE controller has 81%faster response speed and 45%lower steady-state error than the GWO-PD controller.With ITAE,the SEA has good control performance when the internal and external parameters change and can meet the application requirements in non-structural environments.

关 键 词：机器人 弹性执行器 控制器设计 变负载 位置控制 

分 类 号：TP242[自动化与计算机技术—检测技术与自动化装置]