漂浮基柔性关节空间机器人自适应滑模运动控制及振动主动抑制

讨论了关节柔性且系统参数不确定的漂浮基空间机器人系统的动力学建模过程、运动轨迹跟踪控制算法设计及系统柔性振动的主动抑制问题。利用系统动量、动量矩守恒关系和拉格朗日法对系统动力学进行分析,并建立系统动力学方程。基于奇异摄动法将系统分解为表示系统刚性运动部分的慢变子系统和表示系统柔性运动部分的快变子系统。针对慢变子系统提出了一种自适应滑模控制算法。该控制算法是由基于滑模面的等效控制项、自适应控制项和PID反馈控制项组成。因此,它集合了滑模控制、自适应算法和PID技术的优点,且弥补了三种算法各自的缺点。该控制算法能够有效地补偿系统的转动误差和不确定参数,提高控制系统的精度。针对快变子系统,提出基于速度差值的反馈控制算法来抑制柔性关节引起的系统柔性振动,保证系统的稳定性。最后,通过仿真实验证明了提出的混合控制算法的有效性。

Motion adaptive sliding mode control and vibration active suppression of free-floating flexible-joint space robot

The dynamics modeling,motion trajectory tracking control algorithm design and flexible vibration suppression problem of free-floating flexible-joint space robot with uncertain parameters is discussed.Firstly,the system's dynamics is analyzed and the dynamic equation is formulated by incorporating system's linear momentum conservation,angular momentum conservation and the Lagrange equation.Then the system is decomposed into a slow subsystem (rigid motion part) and a fast subsystem (flexible motion part) based on singular perturbation method.For the slow subsystem,an adaptive sliding mode control algorithm is proposed.The algorithm,which is comprised of a sliding mode based equivalent control,an adaptive control and a PID feedback control,integrates the advantages of sliding mode control,adaptive algorithm and PID technology and covers their shortages as well.It can compensate the system's rotation error and uncertain parameters,improve the precision of the control system.For the fast subsystem,a speed difference based feedback control algorithm is proposed to suppress the vibration caused by the flexible-joints,guarantee the stability of the system.Finally,the simulation results validate the efficiency of the proposed hybrid control algorithm.