振动压路机无级调幅H_2/H_∞控制

H_2/H_∞ control for stepless amplitude modulation of vibratory roller

为降低振动压路机无级调幅过程中的压力波动,进一步提高路面压实质量,针对调幅系统具有大时滞和强非线性的特点,综合H2最优控制和H∞鲁棒控制的优点,提出H2/H∞混合控制策略。将液压系统参数摄动到系统压力灵敏度函数的H∞范数作为鲁棒性能评价指标,将负载扭矩波动到振动轮加速度传递函数的H2范数作为线性高斯二次型(LQG)性能指标;基于系统动力学模型,采用Matlab/LMI模块设计了H2/H∞控制器,利用AMEsim液压元件库建立了振动压路机调幅液压系统的动态响应模型,进行联合仿真研究。结果表明:在提出的控制策略下,加速度动态响应经过3 s左右达到稳定,不存在稳态误差;液压系统仅在调幅初始阶段有压力冲击,但冲击幅度很小,仅为2 MPa,且在整个调幅过程中,压力稳定,基本无波动;与传统的PID控制相比,在快速性、准确性和稳定性方面均具有一定的优越性。

To decrease hydraulic pressure vibration and improve compacting quality of road,during amplitude modulation of vibratory roller,aiming at large time-delay and strong nonlinear characteristics,H2/H∞ hybrid controller is designed to ensure both the system performance and the robust stability,by considering the merit and defect of H2 optimal control and H∞ robust control.The H∞ norm of the sensitive function from the parameter perturbation of the hydraulic system to the hydraulic pressure is taken as the evaluating index of the robustness,and the H2 norm of the transfer function from the external torque disturbance to the vibrating accelerate velocity as the index of LQG（linear quadratic Gaussian）.Based on the dynamic model of the system,the controller is designed by Matlab/LMI block.By the AMEsim software,the simulation model is presented.The comprehensive simulations are carried out.The result showed that the response time of vibratory accelerates is 3 s,and there is no stable error under the proposed control method.The maximum impulse of the hydraulic system is 2 MPa,and there is no pressure fluctuation during the adjust process.The robust control is superior to PI control at celerity,accuracy and stability.7 figs,10 refs.