液压振动台非线性摩擦力测量与参数辨识

电液伺服振动试验系统低速和换向时的非线性摩擦力测量和补偿是提高运输环境试验和地震模拟试验等控制精度的重要途径。为了定量获取液压振动台的非线性摩擦力,基于Stribeck效应建立了改进的电液伺服振动试验系统非线性摩擦力理论模型,并结合液压振动台的力平衡方程建立了非线性摩擦力待辨识参数的目标函数。提出一种基于位移闭环控制的简便方法对不同速度下的液压振动台油缸压力差进行测量,得到振动台液压缸与活塞杆之间的摩擦力随速度变化的数值规律。采用基于拟随机序列的混合遗传算法对非线性摩擦力理论模型的4个参数进行了辨识。试验结果证明了本研究方法的可行性,为液压振动试验系统加速度波形失真补偿提供了一定参考。

Measurement and Identification of Nonlinear Friction Force for Electro-hydraulic Servo Shaking Table

Measurement and identification of the nonlinear friction force of an electro-hydraulic servo shaking table at low speed or at the corner of inverse direction is a significant way to enhance its control precision. An improved nonlinear dynamical model of friction force for electro-hydraulic servo shaking table is built according to the Stribeck effect, and the objective function to identify the friction parameters is built based on the force balance equation of electro-hydraulic servo shaking table. Pressure difference of hydraulic cylinder at different velocity of piston is measured by a novel but simplified method, and the mathematical relationship between the velocity and friction of hydraulic cylinder is conformed. Four nonlinear parameters of friction force are identified using a developed hybrid genetic algorithm with quasi random sequences. The feasibility of the modeling and measuring method is verified by comparing the theoretical modeling with experimental results. The research can provide a certain reference for the acceleration distortion compensation of hydraulic shaking table.