摘要
针对液压驱动型并联式加注机器人的空间轨迹跟踪控制问题,提出了一种基于机器人跃度模型和关节扰动估计的分散鲁棒控制策略。通过并联机器人的跃度反解模型将系统基于笛卡尔空间的理想期望轨迹映射为各独立关节的期望轨迹,同时将关节间的耦合交联项处理为各驱动单元的时变外部干扰,进而将并联机器人分解成一组受有界外部扰动关节子系统的集合。针对各独立关节,算法通过反步方法融合了扩张状态观测器和鲁棒控制器,其中扩张状态观测器主要用来实现对关节中匹配不确定性与不匹配不确定性(包括外部扰动和非线性建模误差)的精确估计和补偿,鲁棒控制器用于抑制扰动中超出观测器带宽的快速时变项和其他误差项。通过构造Lyapunov函数从理论上验证了整个闭环系统的稳定性。实验结果表明,提出的控制器能准确估计和补偿各关节子系统中存在的匹配与不匹配不确定性,同时系统具有良好的轨迹跟踪性能和较强的抗干扰能力。
A decentralized robust control method based on the jerk model and an extended state observer is presented for trajectory tracking control in Cartesian space of a hydraulic-driven parallel filling robot. The desired trajectory in Cartesian space is transformed into desired trajectory of each independent joint by using the jerk inverse model of parallel manipulator. Treating the coupled interconnection terms between the joints as time-varying external disturbances of the driving unit, and the parallel manipulator can be decomposed into a set of joint subsystems with bounded external disturbances. For each independent joint, the proposed controller is derived by effectively integrating robust controller with extended state observer via backstepping method. Two extended state observers (ESOs) are synthesized to realize the accurate estimation of both matched and unmatched uncertainties (e.g., external disturbances and nonlinear modeling errors) and compensate them in a feed-forward way. The robust terms are employed to handle the fast-changing components of the uncertainties beyond the pass-band of the ESOs and other error terms. Furthermore, the stability of the system is verified by constructing the Lyapunov function. Experimental results show that the proposed controller can accurately estimate both matched and unmatched uncertainties of the driving unit, and the system possesses high trajectory tracking performance and strong anti-disturbance ability.
作者
赵纯
于存贵
徐强
姚建勇
ZHAO Chun;YU Cungui;XU Qiang;YAO Jianyong(School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2019年第3期164-174,共11页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(51675279)
