Analysis And Chatter-compensation For Friction Of Proportional Multi-way Valve Based On The Lugre Model

Load sensitive proportional multi-way valve has its own advantage of compactstructure, could realize independent control to multi actuators load and convenientconnection, so it has been widely used in the field of hydraulic system in constructionmachinery. Friction will have a great effect on the performance of load sensitiveproportional multi-way valve. The valve friction is the main reason to result in loadsensitive proportional multi-way valve sticking, crawls, flow hysteresis, badmicro-characteristics. Friction shows strong nonlinear characteristics when relativevelocity is slow, especially when the valves in the states of starting、ending and swings.With the improvement of performance in load sensitive proportional multi-way valve,research on friction becomes more and more important.Relying on the load sensitive proportional multi-way valve produced by a companyin china, this paper completes the following aspects:Firstly, based on the multi-function test bed of electric proportional multi-way valve,we built the experimental system about the load sensitive proportional multi-way valve tostudy and analyse friction characteristics. Aiming at oil pressure characteristics of eachoutlet, valve element position characteristics, flow hysteresis characteristics, valve elementmicro-characteristics, experimental study was done. According to experimental data, thefriction is outline measured, the relationship is established between the friction and valvespool relative velocity.Secondly, The LuGre friction model well captures most of the friction behavior inload sensitive proportional multi-way valve.As the model is highly nonlinear, this paperfocuses on the parameter identification of model. According to the LuGre friction model,experimental data and stribeck curve, the friction parameters are acquired by nonlinearidentification based on genetic algorithm.Finally, the author introduces the fundamental of the system identification theory. Thesystem identification theory is applied in analyzing the valve experimental data in thispaper. System identification model is successfully founded whose input is the current and output is displacement of valve element. According to the LuGre friction model based onfixed parameters, friction can obtain effective compensation. According to the simulationof friction compensation by establishing friction observer based on LuGre friction model,the validity of LuGre friction model is verified the validity of LuGre friction model.Aiming at experimental study of friction compensation, a compensation technology whichused high-frequency and low-amplitude chatter signal on input signal was proposed. Thereasonable chatter signal is selected in order to realize the efficient compensation offriction.