Research On Integrated Strategy Control Of Throttle, Brake And Gear Shifting For Traction Control System

With the development of automobile industry, more and more demands to vehicle active safety performance are taken into account. As one of the most important active automobile security control technology, traction control system (TCS) improve driving ability and steering stability of vehicle by preventing driving-wheels from excessive slip to its best mode on low-μroad. So traction control system are widely equipped in all kinds of vehicles. At the same time, the vehicles which equipped in Automatic transmission are increasing, Torque Convert-or and AMT work together, not only have advances of AT, but also low cost. For the engine, TC, and AMT matching in reason, can ensure the Vehicle's power, fuel economic, control stability. Adapt to the situation of our country.But, for the Vehicles which equipped in Automatic transmission , when the TCS acting, because adjust the throttle of engine, driving wheels speed change fastly, induce the transmission shift in high frequency. Like this , the shifting of the Transmission can induce the imbalance of the engine torque, let the TCS system can't work smoothly. So it is necessary to control the Automatic Transmission shifting.Based on the abroad achievements in this field, the dissertations set up the dynamics simulation software; come up with the throttle PI TCS algorithms and brake threshold control algorithms. put forward TC and AMT shifting strategy during the TCS working. And do the Matlab/Simulink and hardware in the loop. Inall, the following research have been finished:1. Acceleration Dynamic Simulation SoftwarePut forward the scheme of acceleration dynamic simulation software. This software include three parts: driver's model,vehicle model,and TCS control logic model. Driver's model simulates driver's attention; Vehicle model including engine model, TC and AMT model ,brake model, driveline model, tire models, vehicle model, assistant model. Established an off-line simulation platform based on Matlab.2. TCS Control Algorithm and TC&AMT Shifting Strategy ResearchDesign the of throttle PI TCS control and brake threshold control algorithms The throttle PI control means on single-μbased on the control of driven slip ratio is taken into account. On split-μroad, can regard the difference of driven-wheel speed as first threshold and rotate acceleretion as second threshold. Put forward several shifting strategy, including hold gear, single parameter shifting, change double parameter shifting, using real vehicle speed shifting, and integrated shifting control.3. Simulation for TCS Control Algorithm and TC&AMT Shifting StrategyIn order to validate the accuracy of TCS algorithm and TC&AMT shifting strategy, this paper builds the throttle PI control and the driving-wheels brake threshold control in Matlab/Simulink. Then on different four roads(low-μroad,split-μroad,step-μroad,checkerboard-μ),a straight-driving simulation study. The simulation results indicate that the control algorithm can prevent excess spin of driving wheel effectively and improve traction, stability, controllability and drivability. TC&AMT shifting strategy have they own advance and disadvance , and integrated shifting strategy have the best result.4. Hardware-in-the-Loop SimulationTo validate the effect of TCS algorithm further, Hardware-in-the-Loopsimulation test is made on low-μroad, split-μroad, and the results indicate that the traction control system based on the throttle PI control and the driving-wheels brake threshold control can prevent excess spin of driving wheel effectively, enhance the traction capability, but for the electronic throttle response slowly driving wheels speed change biggish due to the TC&AMT gear change frequently, and it is for prepare for road test, and on second thoughts to modify the shifting strategy...