Development And Verification Of Joint Control Strategy For Roll And Yaw Of Large Bus

With the popularization of commercial vehicles and the improvement of vehicle performance,people’s traffic is becoming more and more frequent.As one of the main types of commercial vehicles,The inertia of the vehicle is quite large under full loaded.Because of its large passenger capacity,bus safety issues have attracted widespread attention.During the driving process of bus,due to improper driver operation and poor road conditions,there may be situations such as vehicle instability or out-of-control situations.Further deterioration will lead to rollover accidents.Therefore,it is very necessary to develop a joint control strategy to actively control the vehicle to avoid instability when the vehicle is under unstable,thereby protecting the passengers in the vehicle from danger.In this paper,we study the vehicle stability of a large bus that is commonly used in the market,and on the basis of summarizing some studies on stability at home and abroad,we develop a joint control strategy with roll and yaw control capabilities,taking into account real vehicle’s electronic stability control system,for the joint control algorithm,builds a pneumatic braking hardware-in-the-loop test bench and performs a control strategy hardware-in-the-loop test.The main work of this article is as follows:(1)、Build a bus model with Trucksim,at the same time,analyze the causes of the yaw instability of the vehicle and the causes of rollover instability,and formulate the formula for the yaw reference model and the roll control dynamic model.Identify and calibrate the key parameters involved in the model.Improve the accuracy of the reference model and roll dynamic model.(2)、In order to ensure good yaw stability of the vehicle,the yaw stability control frame of the vehicle is formulated,and the reference model and the choice of control variables and the discriminant of the yaw instability of the vehicle are introduced in detail.At the same time,base on the sliding mode variable structure principle calculates the additional yaw moment,and finally adopts the unilateral braking method to control the yaw stability of the vehicle.In order to prevent vehicle rollover,an overall control scheme for vehicle roll control is formulated,and the upper controller and the lower layer of the roll control are separately designed.at the same time according to the principle of differential braking anti rollover,proposed different control target roll moment distribution scheme.(3)、Researched and formulated the ABS anti-lock control strategy.At the same time,the strategy was integrated into the yaw control and roll control strategy to perform off-line simulation tests respectively.On this basis,the bus control strategy was developed and offline.simulation,simulation results show that the joint control strategy can reduce the degree of intervention to the understeering of the vehicle while preventing vehicle rollover.(4)、With reference to the WABCO EBS electronic brake system equipped on the advanced configuration of the study bus,the air brake test bench was simplified,and for the content studied in this paper,the pneumatic brake bench for hardware in the loop suitable for bus was built.The test bench for the hardware-in-loop simulation test of the joint control strategy are carried out.The simulation results show that under the condition of the actual vehicle-electric control system,the combined control strategy of the roll and yaw of the passenger bus developed in this paper still has a good yaw and prevention and rollover control capability.