空间机器人最优能耗捕获目标的自适应跟踪控制

Adaptive Tracking Control for Space Robots with Optimal Energy-Consumptions to Capture a Target

  • 摘要: 提出了一种能够引导末端执行器以期望速度跟踪目标的轨迹规划方法。该方法可以实现避障并满足关节限制要求。基于轨迹规划方法,设计了一种利用自由飘浮空间机器人跟踪与捕获章动自旋卫星的自适应控制策略。此外,该控制策略还考虑了最优能耗、测量误差和优化误差。首先,为了使执行器的跟踪误差和机械臂的能耗最小,将空间机器人的控制策略描述为一个关于关节速度、力矩和避障距离的不等式约束优化问题。然后,推导出一个系数为下三角矩阵的显式状态方程,并对目标函数进行解耦和线性化。设计了一种关节速度和力矩分段优化方法去代替传统的凸二次规划方法求解最优问题,这种方法具有较高的计算效率。最后,利用李雅普诺夫稳定性理论验证了所提控制方法的收敛性。

     

    Abstract: A trajectory planning method is proposed to regulate the manipulator to track the target with the desired velocity. The proposed method can achieve the obstacle avoidance while satisfying joint limits. Based on the trajectory planning method, an adaptive control strategy is designed, by which the free-floating space robot can track and capture a nutational and rotational satellite. In addition, the optimal energy-consumption, measurement errors and optimization errors are considered in the control strategy. Firstly, in order to minimize the end-effector tracking error and manipulator energy-consumption, the space robot control strategy is described as an optimization problem with inequality constraints about the joint velocity, torques and the distance from the obstacles. Then, an explicit state equation with a lower triangular matrix is derived, and the objective function is decoupled and linearized. A piecewise optimization method for the joint velocity and torque is designed to replace the traditional convex quadratic programming method to solve the optimal problem, which demonstrates high computational efficiency. The convergence of the proposed control strategy is verified by Lyapunov stability theory.

     

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