地面装调的空间机械臂在空间应用时的自适应鲁棒控制

针对空间机械臂在轨操控过程中,重力加速度不同于地面装调阶段的重力加速度,会随着空间位置的改变而变化的问题.本文提出了一种自适应鲁棒控制策略,用于空间机械臂的末端控制,从而使在地面重力条件下装调好的空间机械臂能够在空间微重力条件下实现在轨操控任务.通过分析重力项对空间机械臂轨迹跟踪控制的影响,设计自适应律在线估计重力加速度,从而得到重力项的估计,系统的不确定性通过鲁棒控制器来补偿.基于李雅普诺夫理论证明了闭环系统的稳定性.仿真结果表明,在地面装调阶段的重力环境下和空间应用阶段的微重力环境下,该控制器对空间机械臂的末端控制均能达到较高的轨迹跟踪精度,具有重要的工程应用价值.

Adaptive robust control for the space application of manipulator aligned on ground

The gravity acceleration for a space robot in in-orbit operation is different from that in the alignment phase on the ground and subject to change with spatial location. We propose an adaptive robust strategy for the end control of a space robot working in-orbit in the space under microgravity environment, but had the manipulator adjusted on the ground under gravity environment. After analyzing the impact of gravity on trajectory-tracking of the space manipulator, we design an adaptive strategy to estimate the gravity acceleration online, from which we determine the values of related terms. The uncertainty can be compensated by a robust controller. By using the Lyapunov theory, we prove that this control scheme guarantees the stability of the closed-loop system and the asymptotic convergence of tracking errors. Simulation results show that the controller is effective in trajectory-tracking with desired accuracy for the space manipulator to work in the microgravity environment in the space, while had been aligned in the gravity environment. This demonstrates the important value of this strategy in engineering applications.