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研制基于液压位移放大原理的压电陶瓷直接驱动伺服阀(PZT-DDV,Piezoelectric-Direct Drive Valve),实现大流量高频响的要求.分析其结构特点,建立系统数学模型,基于AMESim和Simulink的协同仿真环境,对其进行仿真控制研究.采用AMESim建立了PZTDDV的模型和虚拟液压测试系统,利用Simulink建立了数字控制器模型,通过接口组成协同仿真环境.针对PZT-DDV的迟滞、摩擦和液压位移放大结构的负载敏感特性,采用前馈控制改善迟滞,提高动态响应.基于LuGre摩擦力模型以及密闭腔压力监测,采用自适应backstepping方法实现摩擦及负载变化对放大机构输出位移的扰动补偿.仿真结果表明:前馈控制提高了系统的动态性能,自适应backstepping控制方法提高了系统的稳态控制精度.
The Piezoelectric-Direct Drive Valve (PZT-DDV) based on the theory of hydraulic displacement amplification is developed to meet the requirements of high-flow and high-frequency response.Analysis of its structural characteristics, the establishment of mathematical model of the system, based on AMESim and Simulink Simulation and simulation of the PZT-DDV.The simulation model of PZTDDV and the virtual hydraulic test system are established by using AMESim.The digital controller model is built by Simulink and the simulation environment is composed by the interface.According to the hysteresis, friction and hydraulic pressure of PZT-DDV, The load-sensing characteristic of displacement amplification structure is improved by using feed-forward control to improve the hysteresis and improve the dynamic response.Based on the LuGre friction model and the pressure monitoring in airtight chamber, the backstepping method is used to realize the disturbance compensation to the output displacement of the amplifying mechanism by the friction and load variation. The results show that feedforward control improves the dynamic performance of the system, and the adaptive backstepping control method improves the steady state control accuracy of the system.