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考虑了柔性关节的影响,研究了漂浮基柔性关节空间机械臂系统的动力学建模、运动控制以及柔性振动抑制问题。基于漂浮基柔性关节空间机械臂系统的简化模型,利用系统的动量、动量矩守恒关系和拉格朗日方程建立系统的动力学方程。为了同时实现空间机械臂运动轨迹的渐近跟踪和抑制由柔性关节引起的系统弹性振动,采用奇异摄动法将系统分解为相互独立的慢变和快变子系统。针对慢变子系统,提出模糊滑模控制律以实现空间机械臂期望运动轨迹的渐近跟踪。其中,模糊控制律的应用克服了滑模控制自身的抖振问题;针对快变子系统,采用速度差值反馈控制律来抑制柔性关节引起的系统弹性振动,保证了系统的稳定性。仿真时以平面两刚性杆、两柔性关节的漂浮基空间机械臂系统为例,证明了所提出的混合控制方法的有效性。
Considering the influence of flexible joints, the dynamics modeling, motion control and flexible vibration suppression of flexible joint space manipulator system are studied. Based on the simplified model of the flexible joint space manipulator system with floating bases, the dynamic equations of the system are established by using the system of momentum, momentum conservation and Lagrange equations. In order to realize the asymptotic tracking of the trajectory of the space manipulator and suppress the elastic vibration of the system caused by the flexible joints, the singular perturbation method is adopted to decompose the system into independent slow and fast subsystems. For the slowly variable subsystem, a fuzzy sliding mode control law is proposed to realize the asymptotic tracking of the desired trajectory of the space manipulator. Among them, the application of fuzzy control law overcomes the chattering problem of sliding mode control. For the fast subsystems, the feedback control law of velocity difference is used to restrain the elastic vibration caused by flexible joints and ensure the stability of the system. The simulation results show that the proposed hybrid control method is validated by the planar two-rigid rod and the two flexible joints floating base space manipulator system.