基于自适应反步法的直驱式泵控液压系统控制策略

Control strategy of direct-drive pump-controlled hydraulic system based on adaptive backstepping method

在闭式泵控伺服系统位置输出控制过程中,会出现非对称缸建模难、参数不确定性和控制算法调试困难等问题,为此,提出了一种自适应反步法控制策略(控制器),并采用半实物仿真平台对其可行性进行了验证。首先,推导了考虑单向阀和溢流阀的直驱式泵控非对称缸液压系统的数学模型;其次,采取引入向量的方式,将数学模型变成了严格反馈形式,以此设计了新的自适应反步法控制器,解决了参数不确定问题;最后,在Linux+Preempt-RT半实物仿真平台下,完成了直驱式泵控非对称缸位置系统自适应反步法控制的阶跃信号、正弦信号和加入时变负载的正弦信号试验,并将其控制结果与传统PID控制结果进行了对比分析。研究结果表明:采用自适应反步法的控制器的稳态精度可以达到±3.98 mm,相比PID的控制精度提高了53.6%;同时,在系统位置控制过程中,采用参数自适应律对系统的不确定性参数进行实时调整估计,可以呈现出良好的自适应动态逼近过程。该自适应反步法控制策略具有良好的跟踪性能和鲁棒性。

In the process of position output control of closed pump-controlled servo system,there will be some problems such as difficulty in modeling asymmetric cylinder,uncertainty of parameters and difficulty in debugging control algorithm.Therefore,an adaptive backstepping control strategy(controller)was proposed and its feasibility was verified by hardware-in-the-loop simulation platform.Firstly,the mathematical model of the direct-drive pump-controlled asymmetric cylinder hydraulic system considering the check valve and the relief valve was derived,and the state space equation of the system was re-written.Secondly,by introducing the form of vector,the mathematical model was re-written into a strict feedback form,so as to design a new adaptive backstepping controller to solve the problem of simulation parameter uncertainty to realize the accurate control.Finally,under the Linux+Preempt-RT semi-physical simulation platform,the step signal,sinusoidal signal and sinusoidal signal test with time-varying load of the adaptive backstepping control of the direct-drive pump-controlled asymmetric cylinder position system was completed,the adaptive backstepping control result was compared with the traditional PID control result.The research results show that the steady-state accuracy of the adaptive backstepping control method can reach±3.98 mm,which is 53.6%higher than the traditional PID control accuracy.At the same time,the parameter adaptive law adjusts and estimates the system uncertainty parameters in real time during the system position control process,which can present a good adaptive dynamic approximation process.In summary,the results verify the good tracking performance and robustness of the proposed control strategy.