Research On Integrated Control Of Differential Braking And Active Suspension For Comprehensive Performance Improvement

Driving safety and ride comfort are important directions for the development and innovation of automobiles.How to achieve the improvement of handling stability,ride comfort and roll stability are the key issues of these two directions.As the important parts of chassis active control technology,differential braking and active suspension can greatly improve the stability and ride comfort of the vehicle.However,due to the inherent coupling characteristics of vehicle dynamics,the two subsystems will inevitably have mutual influences and functional conflicts,so it is difficult to make full use of their properties to improve the comprehensive optimal performance of the full vehicle by integrated control method based on simple superposition.Therefore,how to design integrated control system to meet the needs of safety and comfort has become a key point of the research.In response to this key issue,the article focuses on differential brake control,active suspension control and integrated control of the two subsystems.The specific contents are as follows:(1)The vehicle dynamics model including a 14-degree-of-freedom vehicle model and a nonlinear tire model was established using the mechanism modeling method,and the accuracy of the constructed vehicle model was verified through the comparative experiments using the Carsim software,to provide a reliable model basis for the following research.(2)The control method that to improve the handling stability under extreme working conditions was investigated.First,a differential braking controller which integrate the vehicle handling stability and braking force distribution was designed using the model predictive control algorithm framework.Then,the obstacle function method was used to implement the boundary constraint on the wheel slip based on the expected slip rate and the tasks of desired value tracking control and slip control were transformed into constrained optimization problems.Finally,simulation experiments verify that the controller could effectively improve the vehicle’s handling stability under extreme operating conditions,and make full use of the adhesion potential of the tire.(3)The ride comfort and roll stability control method based on active suspension system was investigated.First,the controller was built using Backstepping algorithm.Then,based on the analysis of the control requirements under different working conditions,a timely mode switching control strategy which includes ride comfort mode and roll stability control mode was proposed for the active suspension system.And the switching function was established based on the static stability factor.Finally,the simulations were carried out to verify that the proposed controller can significantly improve the vibration damping performance and anti-rolling performance of the vehicle,and achieve real-time precise control of vehicle under various working condition.(4)The integrated control method of differential braking and active suspension to improve comprehensive performance was studied.First,the interaction between differential braking and active suspension control system on vehicle control was analyzed,and the stability control intervention criterion was introduced as the basis for the control target switching.On this basis,an integrated control strategy for differential braking and active suspension system was established.Then,the integrated control system which includes decision-making organization layer and coordinated control layer was designed using the layered control method.Finally,the effectiveness of the system was verified by the double lane change experiment and fishhook experiment.Based on the advantages of the safety and comfort of the differential brake and active suspension system,the article integrates the two systems through a layered control method to fully exerts their respective functional potential,which provides an effective method for comprehensively improving the safety and comfort of vehicles.At the same time,the research is also in line with the future development trend of automobile intelligence and integration,and owns important research significance and value.