Control Strategies Considering Effect Of Nonlinear Characteristics And Disturbance For Automotive Semi-active Suspension Systems With Mr Damper

With the gradual development of the automotive technology, the ride comfort and road-handling ability of the car have been paid more and more attention. The suspension system, as one of the most important components of the car, plays a role in isolating the road disturbance to improve ride comfort and road-handling ability of the car. The semi-active suspension system has been paid more and more attention because of the simple structure, low power consumption, approximate control performance to the active suspension. This paper presents the mathematical models of the magneto-rheological(MR) semi-active suspension systems based on the full consideration of the systematic nonlinearity and then proposes reasonable control methods for practical problems. The main contents are shown as follows:The mathematical model of the quarter car semi-active suspension system is presented on the basis of the nonlinear characteristic of the MR damper.For the quarter car semi-active suspension model, fully considering the parameter uncertainty, the internal unmeasured state of MR damper and the road disturbance, an adaptive control strategy based on the generalized observer is designed. Simulation results show that, compared to other control methods, the proposed control strategy further improves the control performance of the semi-active suspension system.For the complex nonlinear structure, the internal unmeasured state, the zero-crossing situation of the control coefficient of the quarter car semi-active suspension system and the external road disturbance, a line active disturbance rejection control(LADRC) method is given based on the line extended state observer(LESO) technology. At the same time, for the objective optimizing the body acceleration and the dynamic tire load, a modified LADRC strategy, the double line active disturbance rejection control(DLADRC), is further proposed on the basis of the idea of the skyhook-groundhook hybrid method. Simulation results show that the DLADRC control strategy can further improve the car’s ride comfort and road-handling ability.