柔性空间机器人姿态运动规划的混合优化策略  

Attitude Motion Planning of Flexible Space Robot Based on a Hybrid Optimization Strategy

作　　者：姚其家 戈新生[2] 

机构地区：[1]北京信息科技大学机电工程学院,北京100192 [2]北京信息科技大学理学院,北京100192

出　　处：《力学季刊》2017年第3期428-437,共10页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金(11472058)

摘　　要：自由漂浮是空间机器人执行任务时常用的工作模式,其姿态规划是完成复杂空间任务的基础.针对自由漂浮柔性空间机器人姿态运动规划问题,提出一种由Gauss伪谱法求解可行解与直接打靶法求解更为精确的数值解相结合的混合优化策略.首先,利用假设模态法近似描述柔性臂杆的弹性变形,根据Lagrange方程建立空间机器人系统的动力学模型;然后,利用Gauss伪谱法将空间机器人非完整运动规划问题离散为非线性规划问题,求解在较少Legendre-Gauss(LG)点时状态变量和控制变量对应的可行解,可行解的求解采用从可行解到近似最优解的串行优化策略;最后,在LG点处离散控制变量,作为直接打靶法的初值,利用序列二次规划算法求解最优的控制输入,再通过数值积分得到空间机器人系统姿态运动优化轨迹.通过数值仿真,求解得到的姿态运动曲线光滑平稳,最优控制输入也能很好地满足各种约束条件.结果表明该混合优化策略具有很好的鲁棒性和有效性.Free floating is the working status for the space robots in task and motion planning is the foundation to fulfill a complex space task. For the optimal attitude motion planning problem of free-floating flexible space robots, a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is proposed. Firstly, the elastic deformation of flexible manipulator was described approximately with assumed mode method, and a dynamic model was established by the second Lagrange equation. Then the nonholonomic attitude motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer Legendre-Gauss（LG） points, the feasible solution of state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points and used as the initial values of DSM, the precise optimal control inputs were obtained by sequential quadratic programming（SQP） algorithm. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the optimal trajectory is smooth and stable, and the control inputs match the various constraints of actual conditions well. The results indicate that the method is effective with good robustness.

关 键 词：空间机器人 运动规划 GAUSS伪谱法 直接打靶法 最优控制 

分 类 号：TP241[自动化与计算机技术—检测技术与自动化装置]