基于索驱动的大型柔性结构振动抑制策略研究

Vibration Suppression of Large Flexible Structure Based on Cable-driven Parallel Robots

柔性索并联机构具有工作空间大、能耗低和惯量小等优点,适用于长距离柔性桁架结构的振动主动抑制。首先提出一种四索驱动的柔性体抑振并联机构,根据闭环矢量原理和机构的几何特征,对四索并联机构进行运动学分析。接着建立四索并联机构的静力学模型,并将超长尺度柔性桁架机构的往复振动简化为梁的弯曲振动,利用振型叠加法求解外部激励作用下的强迫响应。最后针对超长尺度柔性桁架机构的振动抑制问题,提出一种基于模糊控制与PID控制相结合的控制策略,通过仿真验证所提控制策略的有效性。结果表明,所设计的柔索并联抑振系统具有明显的抑振效果,柔性桁架的振幅与振动衰减时间大幅降低,且系统的四索索力值能够在合适范围内变化。

With the benefits of large workspace,low energy consumption and small inertia,a flexible cable-driven parallel robot(CDPR)is suitable for vibration suppression of long-size flexible truss mechanism.A flexible cable-driven parallel mechanism used for vibration attenuation of large-size flexible truss is presented.Kinematics and static model of the CDPR is analyzed by principle of closed loop vector and geometric characteristic of mechanism.The long-size flexible truss is simplified as a beam,and the mode superposition method is used to solve the forced response under external excitation.Vibration suppression of the long-size flexible structure with model uncertainties are considered.A control strategy based on fuzzy and PID control scheme is proposed.The simulation results show that the presented system have great affection on the vibration suppression of the long-size flexible truss,whose amplitude and vibration decay time are significantly reduced.In addition,four cable tension values can be changed within a suitable range.