Research On Electro-hydraulic Control Characteristics Of Electronic Limited Slip Differential And Its Driving Anti-skid Control

Electronic Limited Slip Differential(ELSD),as the power distribution unit on the driving axle of the automobile,plays an important role in automobile's drivability,operational stability and driving safety.In this paper,ELSD's electro-hydraulic control characteristics and its application in the driving anti-skid control are studied.Through the combination of physical disassembly,theoretical derivation,simulation research and experimental verification,the influence of different factors on ELSD's oil-pressure output characteristics is obtained and the role of ELSD in the driving anti-skid control is verified.The work above provides a theoretical basis for the design of ELSD's control system.The main contents of this paper are summarized as follows:(1)Through the disassembly of ELSD,its structural characteristics,working principle and electro-hydraulic control circuit are analyzed.The mathematical models of the high-speed on-off valve,electro-hydraulic control circuit and ELSD are established respectively,which provide theoretical basis for the joint simulation.(2)The Simulink/AMESim joint simulation model of the ELSD is established to study its electro-hydraulic control characteristics.According to the simulation experiment,the influence of different factors on the output oil-pressure of ELSD's electro-hydraulic control system is analyzed,including the frequency,duty cycle,amplitude voltage of the signal that controls high-speed on-off valve,the cycloid pump speed,oil path diameter of the hydraulic circuit.According to the characteristics of the ELSD's hydraulic circuit,the test bench is designed and built to verify the simulation results,and some reasonable suggestions are put forward for the control of ELSD.(3)In order to understand the role of ELSD in the driving anti-skid control,the engine model,transmission system model,tire model,driving wheel model and automobile(driven by rear-wheel)kinetic model are established.In order to realize the control of ELSD,the control idea of controlling high adhesion side slip-rate is determined.A PID self-tuning control algorithm based on BP neural network is designed,and its corresponding Simulink module is obtained by MATLAB neural network toolbox.(4)The ideal automobile simulation model of ELSD is built,and the simulation conditions,simulation parameters and simulation methods are determined.According to the difference of the left and right wheels' peak adhesion coefficient,three simulation conditions are established,and the control group of an ordinary differential is set up for the simulation test.By analyzing the change of the slip-rate,driving torque and automobile speed under the control of different differentials,the positive effect of ELSD on the driving anti-skid control and the rationality of the control algorithm are verified.