挖掘机液压系统非线性摩擦的辨识与补偿

Identification and Compensation of Nonlinear Friction in Excavator Hydraulic System

针对挖掘机电液比例控制系统受到液压缸非线性摩擦导致系统稳定性和控制精度降低的现象,提出利用改进粒子群算法和前馈补偿相结合的策略,对控制系统进行优化,以提高系统位移跟踪精度。建立电液系统模型,并用改进的Stribeck模型描述非线性摩擦。通过改进的粒子群算法对模型参数进行辨识优化,根据结构不变性原理设计出一种动态摩擦前馈补偿方法。在此基础上,进行正弦信号、高速工况和低速工况实验。实验结果表明:提出的Stribeck模型和摩擦补偿控制方法可以有效改善低速爬行和平峰现象,并使轨迹追踪精度提高45%左右。

Aiming at the phenomenon that the excavator electro-hydraulic proportional control system is affected by the nonlinear friction of the hydraulic cylinder,the system stability and control accuracy are reduced,a strategy using a combination of an improved particle swarm algorithm and feedforward compensation was proposed and the control system was optimized to improve the displacement tracking accuracy.The electro-hydraulic system model was established,and the nonlinear friction was described by the improved Stribeck model.The model parameters were identified and optimized by the improved particle swarm algorithm,and a dynamic friction feedforward compensation method was designed according to the principle of structural invariance.On this basis,the experimental research of sinusoidal signal,high-speed working condition and low-speed working condition was carried out.Experimental results show that the proposed Stribeck model and friction compensation control method can effectively improve the phenomenon of low-speed crawling and peaking,and improve the trajectory tracking accuracy by about 45%.