基于单应矩阵分解的轮式移动机器人视觉伺服轨迹跟踪

Visual servo trajectory tracking of wheeled mobile robot based on fast decomposition of homography matrix

为了控制移动机器人从当前轨迹跟踪上期望轨迹,设计了一种不需要引入额外变量的机器人轨迹跟踪算法。首先,根据欧式空间下的参考坐标系,与机器人期望坐标系和当前坐标系分别构建单应矩阵,之后通过坐标系变换以及单应矩阵的快速分解得到了当前轨迹与期望轨迹之间的相对位姿关系;然后根据此相对位姿定义了轨迹跟踪误差,求出开环误差方程,最后设计了自适应的视觉伺服轨迹跟踪控制律,并通过李雅普诺夫理论证明了闭环系统渐近稳定。仿真和对比实验结果表明:当t→∞时,移动机器人的当前线速度和角速度与期望线速度和角速度匹配度较高,当前运动轨迹与期望运动轨迹相当一致,当前图像特征点的轨迹序列可以较好地跟踪上期望图像特征点的轨迹序列,此外位姿误差e(t)将收敛于0,且可以使移动机器人跟踪上期望轨迹。

In order to control the mobile robot to track the desired trajectory from the current trajectory,a robot trajectory tracking algorithm without introducing additional variables is designed.Firstly,according to the reference coordinate system of the robot in Euclidean space,homography matrices are constructed with respect to the desired coordinate and the current coordinate,respectively.Then,the relationship between the current trajectory and the desired trajectory is obtained by the coordinate transformation and the rapid decomposition of the homography matrix.The trajectory tracking errors are defined according to the relative pose,and the open-loop error equation can be obtained.Finally,the adaptive visual servo trajectory tracking controllor is designed,and the stablity of the closed-loop system is proved by Lyapunov techniques and extended Barbalat's Lemma.Simulation and contrast experiments show that the current linear velocity and angular velocity of the mobile robot match the expected linear velocity and angular velocity.The current motion trajectory is consistent with the expected motion trajectory.The feature points of the image are almost completely coincident with that of the simulation.The pose error will converge to 0,proving that the mobile robot can track the desired trajectory.