力矩受限的柔性关节空间机器人的鲁棒模糊滑模控制

ROBUST FUZZY SLIDING MODE CONTROL OF FREE-FLOATING SPACE ROBOT WITH FLEXIBLE-JOINTS AND BOUNDED TORQUES

  • 摘要: 讨论了力矩受限情况下具有柔性关节、外部扰动和参数不确定的漂浮基空间机器人系统的动力学建模、运动控制和柔性振动抑制。利用拉格朗日方程和系统的动量、动量矩守恒关系建立系统动力学方程。并基于奇异摄动理论,将系统分解为独立时间尺度的慢变子系统和快变子系统。针对慢变子系统,设计了一种基于双曲正弦函数的鲁棒模糊滑模控制方法,该方法不需要知道系统的精确模型,能够补偿柔性关节带来的系统转角误差,实现空间机器人期望运动轨迹的渐进跟踪。双曲正弦函数的运用有效地降低了控制力矩的幅值,从而使得控制系统能够适应空间实际中力矩受限的情况。而针对快变子系统,设计了速度差值反馈控制方法以抑制柔性关节引起的系统振动,保证系统的稳定性。仿真结果证明了该文所提出的混合控制方法的有效性。

     

    Abstract: The dynamic modeling, the motion control and flexible vibration suppression of a free-floating space robot with flexible-joints, bounded torques, external disturbances and uncertain parameters are discussed. The dynamic equation of the system is established by using the Lagrange equation and the linear and angular momentum conservations of the system. Based on singular perturbation theory, the system is decomposed into a slow subsystem and a fast subsystem. For the slow subsystem, a robust fuzzy sliding mode controller based on hyperbolic sine functions is designed. The controller does not need to know the accurate system model. It can compensate the system rotation angle errors caused by the flexible-joints and can realize the desired motion trajectories asymptotic tracking. The hyperbolic sine functions can reduce the control the amplitude of torques effectively, which makes the control system more realistic. For the fast subsystem, a velocity difference feedback controller is used to suppress the vibration caused by flexible-joints and thus guarantees the system’s stability. The simulation results prove the proposed hybrid controller’s efficiency.

     

/

返回文章
返回