Study On The Dynamic Stability Control Strategy Of Commercial Vehicle For Pneumatic Braking System

Now commercial vehicles have been an important part of the automotive industry and the safety of commercial vehicles have gained a great deal of attention with their rapid development.The Electronic Stability Control(ESC)has already been standard on most active safety systems for passenger cars due to its ability to effectively maintain vehicle stability through braking.It is more difficulty implementing ESC on commercial vehicles because commercial vehicles with pneumatic braking system have a much slower pressure response and built-up speed than passenger cars with hydraulic braking system.Therefore,the purpose of this paper is to apply the experience of our group in developing ESC with hydraulic braking system to develop an electronic stability control system for commercial vehicles with pneumatic braking system.So that we can develop the domestic market and break foreign manufacturers monopoly in this field.The main research contents are as follows:First of all,the components and working principle of the pneumatic braking system used in commercial vehicles are introduced.Based on its working principle and practical application to build a test bench.In order to make the control strategy more suitable for the pneumatic braking system,the response characteristics of the solenoid valve were tested on the test bench.The AMESim model of pneumatic braking system was also established for estimating brake chamber pressure in off-line simulation.Then according to the measured response characteristics of the solenoid valve to design control strategy so that the control strategy and pneumatic braking system can be better matched.According to the basic principle of the electronic stability control system determined the overall architecture of the control strategy.Based on the recognition of the vehicle status,the status of the vehicle can be judged according to the actual value and the ideal value of the selected control variable so that the vehicle can be controlled timely.Subsequently,a two-dimensional fuzzy controller for determining the additional yaw moment was established and described the selection of the target wheel and the distribution of the yaw moment.In order to prevent the occurrence of wheel locking in the process of stability control,an anti-lock brake system which used the logic threshold control method is also added to the control strategy.Then the coordinated control algorithm of electronic stability control system and the anti-lock braking system was put forward so as to ensure the maximum stability of the commercial vehicle with pneumatic braking system.Next,an offline joint simulation of AMESim,TruckSim and Simulink was established in order to verify the validity of the control strategy.In this offline joint simulation AMESim is the building platform for the pneumatic braking system model,TruckSim is the platform for building the vehicle model,and Simulink is the platform for building the whole offline joint simulation control strategy.The simulation conditions were chosen as follow:the sine with dwell and double lane change on the high friction coefficient and low friction coefficient road.The simulation results indicate that the electronic stability control strategy of the commercial vehicle with pneumatic braking system has a good control effect under these conditions.Finally,in order to get closer to the actual driving situation,the built test bench and dSPACE's Simulator and MicroAutoBox were combined into a hardware in-loop test bench to testify the validity of the control strategy again by HILS solution.Download the vehicle model in TruckSim to Simulator and download the electronic stability control strategy to MicroAutoBox.The test conditions chosen in HILS were the same as the test conditions in offline simulation.And the results of the hardware in-loop simulation also indicate the electronic stability control strategy of the commercial vehicle with pneumatic braking system has a good control effect.