Xiao Pengfei, Ju Hehua, Li Qidong
College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210000, China.
The 28th Research Institute of China Electronics Technology Group Corporation, Nanjing 210000, China.
Rev Sci Instrum. 2021 Sep 1;92(9):094501. doi: 10.1063/5.0058391.
This paper studies the Cartesian point-to-point optimal trajectory planning for space robots oriented to space maintenance operations. Aiming at the problems of poor stability, large base disturbance, and large joint variation in the motion planning of point-to-point maintenance in space, a planning method is proposed to minimize the base disturbance and the total joint angle variation under the jerk constraint on the premise of ensuring the accuracy of the end pose. First, the attitude of the space robot is described by the unit quaternion, and the velocity relationship between the joint angle, the end effector, and the base posture is introduced. Then, the joint trajectories were parameterized by a fifth degree polynomial, and a trajectory planning model with the minimum perturbation of the base and the minimum variation of the joint of the manipulator was established under the condition that the end effector satisfied the pose and the jerk constraint. Finally, a multi-objective optimization algorithm is proposed to deal with the trajectory optimization problem under nonlinear constraints. The simulation results show that the proposed trajectory planning method can optimize the base attitude and joint angle of the space manipulator under the premise of the optimal trajectory and stability of the terminal execution tool, which ensures the stability of the space robot's on-orbit service and reduces the energy consumption.
本文研究面向空间维护操作的空间机器人笛卡尔点对点最优轨迹规划。针对空间点对点维护运动规划中稳定性差、基座扰动大、关节变化大等问题，提出一种规划方法，在保证末端位姿精度的前提下，在加加速度约束下使基座扰动和关节总角度变化最小。首先，用单位四元数描述空间机器人的姿态，介绍关节角度、末端执行器和基座姿态之间的速度关系。然后，用五次多项式对关节轨迹进行参数化，在末端执行器满足位姿和加加速度约束的条件下，建立基座扰动最小和机械手关节变化最小的轨迹规划模型。最后，提出一种多目标优化算法来处理非线性约束下的轨迹优化问题。仿真结果表明，所提出的轨迹规划方法能够在终端执行工具轨迹最优和稳定的前提下，优化空间机械手的基座姿态和关节角度，保证了空间机器人在轨服务的稳定性，降低了能量消耗。
