Research On Anti-rollover Control Of Commercial Vehicles Based On Differential Braking

Based on the semi-trailer tractor with three axles,this paper studied the rollover detection of commercial vehicle with three axles and anti-rollover control based on differential braking.Through the analysis of vehicle model and tire model,a method for rollover detection is presented,which is insensitive to vehicle's configuration and structural parameters.When a vehicle is on the verge of rollover,the pulsed barking is applied to the front steering wheels.Assuming the linearized tire dynamics,the load ratio between the inner and outer front wheels,as well as the lateral load transfer ratio(LTR)are estimated based on wheel rotational dynamics.To ensure timely and effective braking excitation on front wheels,the adaptive adjustment of lateral acceleration threshold set for activation of braking excitation is developed.Based on the LTR,which is estimated by the rollover detection method above,the differential braking is used as the main control measure,where LTR is used to trigger the differential braking control and the corresponding lateral acceleration is used as the control target.When the vehicle is in the rollover dangerous condition,if the detected LTR exceeds the threshold,then the brake force is applied to the outer wheels of three axles of the vehicle to reduce the vehicle speed,thereby reducing the vehicle LTR;At the same time,the vehicle lateral acceleration is used as the control target taking the corresponding lateral acceleration of the LTR which triggers the anti rollover control as the threshold,which controls the lateral acceleration under the target threshold,thus to avoid rollover risk and improve vehicle driving safety.Based on the proposed rollover detection method and anti rollover control strategy,first the Trucksim-MATLAB/Simulink joint simulation model of rollover detection based on active braking excitation and of anti-rollover control based on differential braking was built,then the simulation of rollover detection and anti-rollover control were conducted in triple-axle truck under typical danger maneuvers with full load and half load.At the same time,Rollover detection experiments under four typical conditions and the anti-rollover control experiments under three typical conditions were conducted in triple-axle truck under typical danger maneuvers with full load and half load based on the hardware in the loop platform which was bulit with Trucksim vehicle dynamic model,Labview RT system and ABS pneumatic bench for commercial vehicle with three axles.Rollover detection experimental results show that,the presented rollover detection method estimates the rollover risks accurately and effectively with 6.6%for the maximum relative error,and the longitudinal acceleration excited by active braking has fewer effects on vehicle's ride comfort;Anti-rollover experimental results show that,the presented anti-rollover control method can expand the steering wheel range and effectively perform rollover control under the speed of 70km/h,where the angle of steering wheel can be increased up to 70%.