空间自由漂浮机器人对运动目标抓捕的路径规划

发布时间：2019-01-04 13:24

【摘要】：针对空间机械臂对运动目标的抓捕提出了一种分段的在线运动规划方法,重点解决机械臂可能遮挡立体视觉相机视线的问题,并满足抓捕时间要求.基于扩展卡尔曼滤波器(EKF)建立了目标运动状态估计器.对立体视觉相机的视线遮挡约束进行了数学建模.将机械臂向目标的接近过程分成2个阶段,在2个阶段中分别使用多约束环境下的滚动RRT(快速扩展随机树)方法和能够快速接近目标的比例导引算法,并根据对目标运动状态的估计精度自主切换运动段.同时考虑组合体的动力学耦合特性,在运动规划中限制了平台姿态角速度.利用数学仿真验证了本文的目标运动状态估计方法和运动规划方法.比例导引方法可能由于机械臂遮挡立体视觉相机观测视线而抓捕失败,而本文的分段运动规划方法对全部仿真情况都能成功抓捕目标.本文的分段运动规划方法能够对各个方向运动的目标进行有效的运动状态估计并快速可靠地抓捕,避免了因遮挡立体视觉相机观测视线引起的抓捕失败.基于目标运动状态估计的切换策略能够根据实际的目标运动情况在线自主地切换2个运动段,对运动状态未知的目标具有鲁棒性.
[Abstract]:A piecewise online motion planning method is proposed for the capture of moving objects by space manipulator, which focuses on solving the problem that the robot arm may block the sight of stereo vision camera and meet the requirements of capture time. Based on the extended Kalman filter (EKF), a target motion state estimator is established. The line of sight occlusion constraint of stereo vision camera is modeled mathematically. The approach process of robot arm to target is divided into two stages. The rolling RRT (fast extended random tree) method in multi-constrained environment and the proportional guidance algorithm which can approach the target quickly are used in the two phases, respectively. According to the estimation accuracy of the target motion state, the motion segment is switched autonomously. At the same time, considering the dynamic coupling characteristics of the composite body, the angular velocity of the platform attitude is limited in motion planning. The method of motion state estimation and motion planning are verified by mathematical simulation. The proportional guidance method may fail because of the robot arm blocking the observation line of sight of stereo vision camera, but the segmented motion planning method in this paper can capture the target successfully for all the simulation cases. The segmented motion planning method in this paper can effectively estimate the moving state of the moving target in various directions and capture quickly and reliably, thus avoiding the capture failure caused by the line of sight observed by the stereo vision camera. The handoff strategy based on target motion state estimation can automatically switch two motion segments on line according to the actual target motion, which is robust to the target with unknown motion state.
【作者单位】：哈尔滨工业大学航天学院;哈尔滨工业大学机电工程学院;
【基金】：国家科技支撑计划(2015BAK06B00)
【分类号】：TP242;V441

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