冲击载荷下的磁流变减振器动力学建模与滑模控制

Dynamic Modeling and Its Sliding Controller of MR Shock Absorber under Impact Load

以冲击载荷下的磁流变减振器为对象,设计一单杆长行程冲击型减振器,基于Bingham模型推导建立包括由环形阻尼孔内的摩擦阻尼力、库仑阻尼力、惯性阻尼力、节流阻尼力、结构附加阻尼力和摩擦阻尼力等组成的动力学模型,并利用最小二乘算法辨识模型中关键参数,试验结果证实了拟合的磁流变冲击减振器动力学模型准确性。针对冲击载荷特点,设计基于全状态反馈和指数趋近律控制率的滑模变结构目标跟踪控制器,基于构建的试验平台分析比较On-Off算法、PID算法和滑模控制算法控制效果,结果显示滑模控制算法下的磁流变冲击减振器振动峰值缩减27.33%,活塞行程缩减48.75%,控制效果最为理想。

An MR shock absorber under impact load is investigated.A single-rod long-stroke impact absorber is developed.Based on Bingham model and its structure of MR damper under impact load,a dynamic model of MR damper under impact load is derived,which is composed of annular damping hole＇s friction damping force,coulomb damping force,inertia damping force,throttle damping force,structure additional damper force and other friction forces.By applying the least square algorithm,important parameters in the dynamic model are identified.Experimental results confirm the accuracy of the derived and fitted dynamic model.According to its strong nonlinearity,wide frequency range and high peak-value of acceleration characteristics of impact load,an output target tracer using sliding control strategy is designed and simulated on the basis of constructing hardware-in-the-loop platform.The control effects of three control strategies,namely,On-Off strategy,PID strategy and sliding mode control strategy,are compared and analyzed.The results show that the vibration peak value of MR impact absorber under sliding mode control strategy is reduced by 27.33%,and its piston stroke is reduced by 48.75%,thus being the most ideal control effect.