A Prediction and Motion-Planning Scheme for Visually Guided Robotic Capturing of Free-Floating Tumbling Objects With Uncertain Dynamics
A Prediction and Motion-Planning Scheme for Visually Guided Robotic Capturing of Free-Floating Tumbling Objects With Uncertain Dynamics
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DOI：
10.1109/tro.2011.2179581
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发表时间：
2012-06-01
影响因子：
7.8
通讯作者：
Aghili, Farhad
中科院分区：
文献类型：
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作者：
Aghili, Farhad
视觉引导的机器人捕获移动对象通常需要对对象运动的长期预测，这不仅是为了平滑捕获，而且因为视觉反馈可能不是连续可用的，例如，例如，在一个实施例中，也是由于机器人手臂的视觉障碍。本文提出了一种结合预测和运动规划方案的机器人捕获的漂移和翻滚的对象与未知的动态视觉反馈。卡尔曼滤波器从视觉系统的噪声测量中估计长期预测运动所需的对象的状态和一组动态参数。随后，估计的状态，参数和预测的运动轨迹被用来规划机器人的末端执行器的轨迹，以拦截抓斗夹具上的对象与零相对速度（以避免影响）在一个最佳的方式。最佳轨迹最小化成本函数，其是行进时间、距离、视线角度的余弦（用于机器人抓取的对象对准）和作为对加速度幅度的约束的惩罚函数的加权线性和。实验证明机器人运动规划方案的自主抓取翻滚的卫星。采用两个机器人操纵器：一个手臂漂移和翻滚的卫星模型，另一个手臂，配备了一个机器人手试图捕捉一个抓斗固定在卫星上使用的视觉制导系统。
Visually guided robotic capturing of a moving object often requires long-term prediction of the object motion not only for a smooth capture but because visual feedback may not be continually available, e. g., due to vision obstruction by the robotic arm, as well. This paper presents a combined prediction and motion-planning scheme for robotic capturing of a drifting and tumbling object with unknown dynamics using visual feedback. A Kalman filter estimates the states and a set of dynamics parameters of the object needed for long-term prediction of the motion from noisy measurements of a vision system. Subsequently, the estimated states, parameters, and predicted motion trajectories are used to plan the trajectory of the robot's end-effector to intercept a grapple fixture on the object with zero relative velocity (to avoid impact) in an optimal way. The optimal trajectory minimizes a cost function, which is a weighted linear sum of travel time, distance, cosine of a line-of-sight angle (object alignment for robotic grasping), and a penalty function acting as a constraint on acceleration magnitude. Experiments are presented to demonstrate the robot-motion planning scheme for autonomous grasping of a tumbling satellite. Two robotics manipulators are employed: One arm drifts and tumbles the mockup of a satellite, and the other arm that is equipped with a robotic hand tries to capture a grapple fixture on the satellite using the visual guidance system.