基于预测控制器的电液伺服系统节能方法研究

Research on Energy Saving Method for Electro⁃hydraulic Servo System Based on Predictive Controller

设计基于预测控制器的电液伺服系统节能方法,以控制电液伺服系统准确追踪期望位置的同时,达到节能的效果。从电液伺服系统的原理出发,分析电液伺服系统的工作原理及结构组成。利用比例方向控制阀阀芯位移,计算出液压缸腔室与油箱压力及供给压力间的压差值。利用活塞位移求取腔室内的压力连续性方程。在考虑比例方向控制阀阻尼系数的基础上,建立其对应的运动方程。利用比例溢流阀的开度,求取其动态方程。通过腔室压力值、比例溢流阀的开度,建立电液伺服系统的状态模型。以期望位置为依据,计算出腔室内压力的期望值,进而求取所需供给压力。利用所需供给压力,构造预测控制器,对电机的转速进行预测控制,以达到动态调节供给压力的效果,实现节能控制。实验结果表明:与采用滑模控制的恒压方法相比,该方法对正弦及随机期望位置的追踪精度分别提高了44.93%和39.98%,对应的能耗分别降低了13.45%和10.54%。该方法对电液伺服系统的位置控制效果及节能控制效果都较好。

The energy saving method for electro⁃hydraulic servo system based on predictive controller was designed to achieve the effect of energy saving while the electro⁃hydraulic servo system was controlled to track the expected position accurately.Based on the principle of electro⁃hydraulic servo system,the working principle and structure of the electro⁃hydraulic servo system were analyzed.The pressure differences between the chamber of the hydraulic cylinder and the pressure of the oil tank and the supply pressure were calcu⁃lated by using the valve core displacement of the proportional directional control valve.By using the displacement of the piston,the pressure continuity equation in the chamber was obtained.On the basis of considering the damping coefficient of the proportional direc⁃tional control valve,the corresponding motion equation was established.The dynamic equation of the proportional relief valve was ob⁃tained by using its opening degree.The state model of the electro⁃hydraulic servo system was established by using the chamber pressure and the opening degree of the proportional relief valve.Based on the expected position,the expected pressure in the chamber was cal⁃culated,and then the required supply pressure was obtained.By using the required supply pressure,a predictive controller was con⁃structed to predict and control the speed of the motor,then the effect of dynamic regulation of supply pressure was achieved and energy saving control was realized.The experimental results show that compared with the constant pressure method using sliding mode control,the tracking accuracy of the method for sine and random expected position is improved by 44.93%and 39.98%respectively,and the corresponding energy consumption is reduced by 13.45%and 10.54%respectively.This method has a good effect on the position con⁃trol and energy saving control of the electro⁃hydraulic servo system.