移动机械臂手眼关系标定及视觉伺服控制方法

Hand-eye calibration and visual servo control for mobile manipulator

将视觉传感器集成到移动机械臂上构成眼在手上构型的视觉伺服系统是服务机器人实现物品抓取与搬运操作的一种有效方法,但存在手眼关系标定算法复杂非线性,以及难以处理移动机械臂的非完整性约束等难题。为了克服以上难题,首先将移动机械臂抽象为一个广义机械臂,对其进行运动学建模,并求出其运动学解析逆解;然后提出一种全新的线性主动视觉摄像机标定方法对手眼关系进行标定;最后设计包含眼注视逼近和look-thendoing开环抓取的视觉伺服切换控制律来控制移动机械臂实现家庭物品的抓取操作。仿真及试验结果表明,该线性手眼关系标定法易于实现,且具有极高的标定精度,同时设计的视觉伺服切换控制律能够有效克服移动机械臂的非完整性约束带来的控制困难。

The eye-in-hand visual servo system integrated vision sensor into mobile manipulator was widely used for object grasping and delivering operation. However,there were some challenges,such as nonlinearity and complexity of the existing hand-eye calibration algorithm,together with the nonholonomic constraint of the mobile manipulator. To solve these problems,the mobile manipulator was proceeded as a generalized manipulator whose kinematic model was established,and the inverse kinematic analytical solutions were acquired. Then,a novel linear active vision based camera calibration method was proposed to determine the hand-eye relationship. Finally,a visual servo switching control lawcomposed of eye-fixed approaching and look-then-doing open loop handling was designed to control the mobile manipulator to finish household objects handling operation. Simulation and experimental results showed that the linear active vision-based hand-eye calibration method could be utilized conveniently and precisely. Meanwhile,the designed control lawcould reduce the control difficulty brought by the nonholonomic constraint of the mobile manipulator.