以Stewart并联机构主动隔振平台为研究对象,提出一种非线性L2鲁棒主动隔振控制方法.应用牛顿一欧拉方法建立了由直线音圈电机驱动的隔振平台的完整动力学模型.在模型非匹配不确定性的上界未知的情况下,充分考虑动力学模型的非线性特性、参数摄动以及未建模动态等因素对隔振控制的影响,设计了模型非匹配不确定性上界估计的调节律并推导出鲁棒主动隔振控制律.通过构造合适的存储函数,在理论上证明了系统的稳定性和满足L2性能准则的隔振性能.仿真结果表明,该方法能有效地抑制6个方向的低频振动,得到满意的隔振性能。
A nonlinear L2 robust active vibration isolation control approach is proposed for the active vibration isolation platform based on Stewart parallel mechanism. The entire dynamic model of the vibration isolation platform driven by the linear voice coil motors is developed with Newton-Euler method. Without knowing the upper bound of the unmatched uncertainties of the model, the influence factors of vibration isolation, such as the nonlinear characteristics of the dynamic model, the parameter perturbation and the unmodeled dynamics, are fully taken into account. A tuning rule is designed to estimate the unknown upper bound of the unmatched uncertainties. Moreover, a robust active vibration isolation controller is derived. By constructing appropriate storage functions, the controller stability and the L2 performance criterion based vibration isolation performance are verified theoretically. The simulation results demonstrate that the controller can effectively attenuate low-frequency vibrations in all six degrees of freedom and the satisfactory vibration isolation performance can be achieved.