未知雅可比建模的机器人视觉伺服自抗扰控制方法

Unknown Jacobian modeling robot visual servoing with active disturbance rejection control method

针对系统标定和雅可比在线求解难问题,引入非线性状态反馈,研究一种基于自抗扰控制器(ADRC)的机器人视觉伺服控制算法.利用无模型理论和非线性自抗扰技术建立机器人“视觉-运动”空间映射,进而设计不依赖雅可比建模的视觉反馈控制器,其中采用跟踪微分器(TD)跟踪视觉空间期望特征;利用扩展状态观测器(ESO)实现未建模雅可比反馈补偿;最后利用非线性状态误差反馈(NLSEF)规则得出机器人运动空间控制量.本文构建的视觉伺服控制方案面向未知系统标定和目标深度信息的机器人任务操作.手眼标定六自由度无标定机器人抓取定位的实验表明,视觉空间特征轨迹平滑稳定在相机视场中,笛卡尔空间机器人末端运动平稳,无震荡回退,抓取定位精度高.

Considering problems of system calibrations and Jacobian on-line calculations,we propose a visual servoing algorithm with active disturbance rejection controller(ADRC)by introducing nonlinear state feedbacks.The model-free theory and nonlinear ADRC techniques are used to construct robot"visual-motion"space mapping.Then,a visual feedback controller is designed independently of the Jacobian modeling,in which desired image features are tracked by tracking differentiator(TD).The unknown Jacobian modeling is compensated by extended state observer(ESO),and the nonlinear states error feedback(NLSEF)rule is used for robot motion control.The proposed visual servoing scheme is suited for the robot task manipulation without system calibrations and target depth information.The eye-in-hand six degree of freedom robot grasping and positioning experiment show the smoothness in trajectories of image features and stabilities in the field of view(FOV)of the camera.Finally,the movement of the robot end-effector is stable with no vibrations and retreats in Cartesian space,and the end-effector with high accuracy of grasping and positioning is also observed.