【作者】 刘厚德；

【导师】 梁斌； 徐文福；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2014， 博士

【摘要】 随着空间技术的发展，人类空间活动日益频繁，为了提高工作效率和降低宇航员的风险，空间机器人将在未来的在轨服务中扮演越来越重要的角色，而目标捕获是在轨服务的一项关键技术。本文以国家863计划航天领域某重大项目为背景，开展自旋目标捕获的协调运动规划研究，为未来我国空间机器人在轨服务技术的实用化奠定基础。实际在轨服务的对象为在轨故障卫星、空间垃圾等，可能处于自旋运动状态，这对目标捕获提出了巨大挑战。经过大量调研，总结了自旋目标的实际运动特征，并从理论上建立了其运动学模型，根据该模型采用无损卡尔曼滤波方法对其运动状态进行预测，基于此提出了单臂自主捕获及双臂协调的运动规划方法，实现对自旋目标的成功捕获。由于存在动力学耦合，机械臂的运动会改变基座的姿态及质心位置，从而影响任务的执行。首先建立了“基座质心等效机械臂”的模型，基于此提出了保持基座稳定的无奇异多臂协调运动规划方法。通过求解等效机械臂的位置级逆运动学确定平衡臂的运动轨迹，不需求解微分运动学方程，可很好地回避了传统方法中存在的雅克比矩阵奇异的问题。该方法对平衡臂的运动学和动力学参数及安装位置无特殊要求，具有更好的通用性。与捕获前的状态相比，目标捕获后形成的复合体系统的质量特性和动量发生了很大改变，可能失稳。针对此问题提出了两种基于角动量守恒的协调规划方法：关节阻尼和关节函数参数化。通过协调规划各关节和飞轮的速度实现对系统角动量的重分配。在此基础上，采用粒子群算法优化关节函数参数，在实现目标停靠的同时保证基座姿态的偏转最小。该方法采用实际飞轮作为动量交换装置，具有很好的工程可实现性。为了对协调运动规划方法进行实验验证，基于动力学模拟与运动学等效的思想建立了一套地面实验系统。提出了两种基于6自由度工业机器人的自旋运动模拟方法：机械臂末端运动模拟法和机械臂肩部奇异运动模拟法。后者充分利用了肩部奇异构型的运动特性，考虑了实际的关节约束，具有很强的工程可实现性。该系统具备多种任务的演示能力，可充分利用成熟的工业产品，减少了开发成本和时间，利用该系统对自旋目标自主捕获规划方法进行验证和评估。本文的研究面向未来高轨在轨服务中急需解决的自旋目标自主捕获问题，顺应了我国大力发展空间机器人在轨服务技术的大方向，对于未来开展空间机器人在轨维护、装配、援救等任务，具有重要的理论研究意义和工程应用价值。更多还原

【Abstract】 With the development of space technology, space activities of human have become increasingly frequent. Space robot will play an increasingly important role in efficiency improvement and astronauts’ risk reduction. Target autonomous capture is the key technology of space robotic applications. This thesis was based on a project sponsored by the National High-Tech863Program in aerospace industry, and researches coordinated motion planning for spinning target capturing, which lays the foundation for the practical of future services technology.In fact, targets to be serviced in orbit are failure satellite, space debris, etc. These objects are in spin motion state that it is very difficult to capture them. Based on extensive research, we summed up the characteristics of the real movement of the spinning target and established its kinematic model which can be used to predict its movement by Unscented Kalman Filter (UKF), and then methods of autonomous capture and coordinated motion planning were proposed to capture the spin target successfully.Due to the existed of dynamic coupling, the motion of the arms will alter the attitude and position of the base, which can affect the implementation of the task. Firstly, established a “base centroid equivalent manipulator” model, then the singularity-free method was proposed to plan the coordinated trajectories of the balance arms. With solving inverse kinematics of the equivalent manipulator instead of solving the differential motion equations to determine the trajectory of the balance arm, the jacobian matrix singularity is avoided. Furthermore, there are not any specific constraints on the configuration, mass properties, geometry parameters and mounted position of the balance arm.The captured coupling system may be unstable due to the change of the quality characteristics and momentum, thus, two coordinated plan methods—joint damping and parameters of joint function configurable, were proposed to solve this problem. According to these methods, management and re-distribution of angular momentum were used to stabilize the coupling system by planning and controlling the velocity of the flywheel and joints. On the basis of them, PSO algorithm was used to optimize the parameters of joint function in order to ensure the minimum deflection of the base attitude. These methods adopted the actual flywheel as momentum exchange device, which can obtain great effectiveness in engineering. In order to verify the motion planning methods, a ground experiment system was developed based on the idea of dynamics simulation and the principle of kinematic equivalent. Then two methods of motion simulation, which were based on6-DOF industrial robot, were proposed: the conventional simulation method and shoulder singularity method. The second method owned a strong engineering feasibility, which took the advantage of the motion characteristics of the shoulder singular and considered actual joint constraint. The experimental system used commercial devices which was relatively low cost and easily to be implemented. In this system, the path plan method of spin target autonomous capture by space robot could be verified and evaluatedThe research in this dissertation is focused on the autonomous capture of spinning target which has to be settled urgently in servicing mission on high orbit in the future. It conforms to the trend on the development of on orbit service using space robot in our country, and has an important theoretical and practical significance in orbital maintenance, assembly, and rescue using space robot.更多还原