Research On Sliding Mode Control Of MR Damper Suspension For Heavy Truck Cab Based On Fuzzy Disturbance Observer

With people’s yearning for a high-quality life,people have higher requirements for ride comfort and driving control.In particular,the drivers and passengers of heavy trucks will work for a long time in the environment with complex road conditions,and the bumps caused by uneven road surfaces will greatly affect their health.However,at present,most heavy trucks use passive suspension for vibration reduction.The fixed structural parameters limit the vibration reduction performance,while the active suspension requires a large amount of energy from the outside,resulting in a high cost.The semi-active suspension has a broad application prospect because of its simple structure,low energy consumption,and similar vibration reduction performance to the active suspension.Magnetorheological semi-active suspensions have been widely studied by scholars for their advantages of fast response time and high adjustable ratio of damping force using magnetorheological dampers.Since the control strategy is the key technology of magnetorheological semi-active suspension system,a single control strategy cannot take into account the suspension performance.Therefore,this paper designs a new labyrinth-type dual-channel valved magnetorheological damper（LDCV-MRD）to form a semi-active suspension system and carries out the research of sliding mode control strategy based on fuzzy disturbance observer,the main work is as follows:（1）The performance evaluation index of the suspension is selected according to the influence of the suspension on the three aspects of vehicle driving smoothness,vehicle handling stability and driving safety.The dynamics of a 1/4 vehicle 2-degree-of-freedom suspension system is analyzed by means of Newtonian mechanical equilibrium equations for a magnetorheological semi-active suspension,and its differential equations of motion are derived.Mechanical analysis of the structure of the used LDCV-MRD,resulting in a magnetorheological damper forward model.Conduct magnetorheological damper characteristics tests and establish a polynomial inverse model for magnetorheological dampers by combining the experimental results.（2）Design the switching function and convergence law of the sliding mode controller,design the sliding mode controller on this basis,and prove the stability of the design result by the Liapunov stability criterion.Then the disturbance observer is designed and the necessary conditions for the stabilization of the disturbance observer are derived by establishing a connection between the Liapunov stability criterion and the sliding mode controller,and then the fuzzy rule control is designed to regulate the three parameters k₁,k₂,and l₂ in the sliding mode controller and the disturbance observer.（3）The relevant theoretical derivation and model building are performed for impact road excitation,sinusoidal road excitation,and random road excitation inputs.Matlab/Simulink software is used to simulate and analyze three aspects of suspension vertical acceleration,suspension dynamic deflection,and tire dynamic deformation for a semi-active suspension system with the LDCV-MRD based on sliding mode control with a fuzzy disturbance observer,and to compare it with a passive suspension.The simulation results show a 33.57%average decrease in vertical acceleration,a 25.22%average decrease in suspension dynamic deflection,and a 29.8%average decrease in tire dynamic deformation,which are all substantial improvements.（4）Build a 1/4 vehicle suspension system hardware-in-the-loop experimental bench,conduct hardware-in-the-loop bench experiments on the designed semi-active suspension system,and compare the fuzzy disturbance observer-based sliding mode control semi-active suspension of heavy trucks with the passive suspension of heavy trucks designed in this paper.The experimental results show that the average decrease in vertical acceleration is 28.81%,the average decrease in suspension dynamic deflection is22.1%and the average decrease in tire dynamic deformation is 34.13%,which can effectively improve the smoothness,handling stability and driving safety of the vehicle.