基于模型降阶与链式结构的平面欠驱动机械臂位姿控制  

Position and posture control for a planar underactuated manipulator based on model reduction and chained structure

作　　者：刘东 万雄波 王亚午 赖旭芝 吴敏 Dong LIU;Xiongbo WAN;Yawu WANG;Xuzhi LAI;Min WU(School of Automation,China University of Geosciences,Wuhan 430074,China;Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems,Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)自动化学院,武汉430074 [2]复杂系统先进控制与智能自动化湖北省重点实验室,武汉430074

出　　处：《中国科学：信息科学》2020年第5期718-733,共16页Scientia Sinica(Informationis)

基　　金：国家自然科学基金(批准号:61773353);青年科学基金(批准号:61903344);湖北省自然科学基金创新群体(批准号:2015CFA010);高等学校学科创新引智计划(批准号:B17040)资助项目。

摘　　要：针对第三关节为被动的平面四连杆(active-active-passive-active,简称AAPA)欠驱动机械臂的位姿控制问题,提出一种基于模型降阶与链式结构的控制策略.整个控制过程被划分为3个阶段.第1阶段,通过控制第四连杆的角度至零,将平面AAPA机械臂降阶为平面虚拟四连杆(active-activepassive,简称AAP)欠驱动机械臂.第2阶段,首先将平面虚拟AAP机械臂的模型转换为标准链式结构形式.然后,设计相应的控制器将平面虚拟AAP机械臂的被动关节控制至其目标位置,同时,将被动连杆的姿态角控制至中间姿态角,从而将平面AAPA机械臂进一步降阶为平面Acrobot.第3阶段,控制平面Acrobot驱动连杆的角度至其目标角度,连带实现对被动连杆的角度控制,最终实现平面AAPA机械臂的位姿控制目标.考虑到平面Acrobot存在角度约束,因此,利用遗传算法协调与优化被动关节的目标位置、被动连杆的中间姿态角、第四连杆的目标角度与被动连杆的目标姿态角,确保平面Acrobot对于系统目标位姿的目标角度解存在.最后,通过仿真验证控制策略的有效性.A control strategy is proposed based on the model reduction and the chained structure for a planar four-link(Active-Active-Passive-Active,AAPA)underactuated manipulator to achieve its position-posture control objective.The whole control process is divided into three stages.In the first stage,the planar AAPA manipulator is reduced to the planar virtual three-link(Active-Active-Passive,AAP)manipulator by controlling the angle of the fourth link and rotating it to zero.In the second stage,the model of a planar virtual AAP manipulator is transformed into the standard chain structure form.Then,the corresponding controllers are designed to control the passive joint of the planar virtual AAP manipulator to its target position,and the posture angle of the passive link is controlled to its middle posture angle at the same time.At the end of this stage,the planar AAPA manipulator is reduced to the planar Acrobot.In the third stage,the angle of the active link of the planar Acrobot is controlled to its target angle.Also,the angle control of the passive link of the system is realized.Consequently,the position-posture control objective of the planar AAPA manipulator is recognized.Considering the angle constraint of the planar Acrobot,the genetic algorithm is used to coordinate and optimize the target angle of the passive joint,the middle posture angle of the passive link,the target angle of the fourth link,and the target posture angle of the passive link.These ensure the target angles of the planar Acrobot corresponding to the target position-posture of the system can be found.Finally,simulation results demonstrate the effectiveness of the proposed control strategy.

关 键 词：平面四连杆欠驱动机械臂 位姿控制 模型降阶 链式结构 遗传算法 

分 类 号：TP241[自动化与计算机技术—检测技术与自动化装置]