Research On Roll Control Based On Magnetorheological Damper With Large Damping Force Under Low Speed

During the turning of the vehicle,under the combined effect of centrifugal torque and the unevenness of the road,the vehicle will tilt to the outside of the curve.When the roll phenomenon is serious,the vehicle may lose stability or even roll over,which result in the vehicle Driving safety problem.At present,the roll control is mainly achieved by installing an active suspension,but the active suspension has a complicated structure and serious energy consumption,and is not the most economical and practical method.A scheme is proposed to use a magnetorheological damper with large damping force under low speed for roll control to reduce the roll angle of the vehicle body.The main work includes the design and simulation analysis of the magnetorheological damper,as well as the control design and simulation verification,which are embodied in the following four aspects.(1)In this paper,a shear mode magnetorheological damper with low speed and large damping characteristics is designed.In order to ensure that the performance of the damper can meet the needs of roll control,the magnetic circuit of the magnetorheological damper emphasis on the design,the simulation analysis the structural parameters that can affect the maximum output damping force of the magnetorheological shock absorber,the simulation results show that the maximum damping force of the designed shear mode magnetorheological damper meets the design requirements,and shows obvious low-speed large damping characteristics.(2)Based on the output characteristic curve of the magnetorheological shock absorber,a polynomial mathematical model of the magnetorheological shock absorber is established.The inverse model of the current control is solved based on the frame motion status and the target control force.A six-degree-of-freedom steering-roll vehicle dynamics model and road roughness excitation model were built.(3)The design takes the zero roll angle as the control target,and considers the smoothness of the optimal controller,and performs the simulation of the angular step condition and the double-shift line condition respectively.The simulation results show that the designed shear-type magnetorheological shock absorber can obtain better roll control effect than traditional valve-type magnetorheological shock absorber,and the lateral load transfer rate,suspension dynamic deflection,tire Parameters such as dynamic displacement have also been improved to a certain extent,while achieving a better anti-rolling effect,to a certain extent,the stability and smoothness of the vehicle during driving are ensured.(4)Based on the vehicle dynamics model and the magnetorheological shock absorber mathematical model,the related researches of the model predictive controller are carried out.The nonlinear system is transformed into a linear system with nonlinear damping force constraints,and the zero-roll angle is used as the control target,and the simulation analysis under the condition of double-shift line is carried out.The results show that the model predictive controller can further improve the anti-roll performance to a certain extent.