Study On The Development Of Vehicle Stability Control System Based On Active Braking

The Paper is about Real-car development for vehicle stability control system based on active braking. It describes vehicle dynamic modeling, VSC control principle analysis, control algorithm design, debug method and Real-car test on the basis of former researchers'production.The VSC is a system that relies on the vehicle's braking system as a tool for"steering"the vehicle. When the stability-control function assumes operation it shifts the priorities that govern the brake system. VSC research is an international focus in the vehicle active safety field. With the development of control technology and decrease of control system cost, VSC is replacing ABS to be the standard equipment of modern vehicles. In recent years, more and more VSC or equivalent devices were used on vehicles in aboard, while in China, VSC is a whole new thing, not mention to deep research. Some universities and institutes such as Jilin University, Tinghua University, Beijing Technology Institute and Heavy Truck Group, did some research on the VSC simulation, but it is superficial. Hence, it is quite significant to study on the Real-car development for VSC not only on the understanding but also on the application prospect.The development of VSC comprises mechanics, electronic, hydraulic, vehicle dynamics modeling, software and hardware design, driving actions, field test and validation. For the disadvantage of traditional vehicle active safety system development method such as long test lead time, low test efficiency and test accidents easily introduced, a new development method based on model design is proposed in this paper and is put into application for VSC development. This design method covers the whole process of concept and function design, system modeling, off-line simulation, code automatic generation, real-time hardware-in-the-loop (HiL) simulation and final validation of vehicle test. In the guide of this new development method, the work for VSC development is listed as following:Firstly, in the Chapter 1 and 2, the constituent, function, system nature and working conditions are introduced. The dynamics model including vehicle dynamics, tire model, controller model, hydraulic system model and brake actuators, is the base of the model based design and development, and it is responsible for the efficiency and precision of the development. So a special VSC system dynamics model, which can discover the nature of the research focus as well as satisfy real-time simulation requirements, is established. In order to validate the vehicle dynamics model, a vehicle field test is introduced. From the results of three typical conditions'result - bra king, steering and braking while steering, we can see that the simulation result is correct and can be used in the VSC research.Secondly, design method based on the model and its application for the VSC development is described in detail. The whole process of this development method is showed in this chapter including VDC simulation model design, test bench interface device and drive circuit, the vehicle field test for control prototyping on dSPACE, C code auto generation and hardware design for ECU, ECU-in-the-loop simulation test, ECU calibration and the vehicle field test.In the chapter 4, VSC control algorithm based on the direct intervention yaw moment by active braking is proposed. The control algorithm decides the vehicle yaw moment by using robust-fuzzy control method based on the errors of vehicle yaw rate and vehicle side slip angle. The target yaw moment is achieved by individual wheel active braking, the vehicle keep on the track of driver commanded. The combined estimation method is introduced on the basis of former fruits. Design failure mode effect and analysis is discussed. The simulation and Real-car test results show that the control law is effective and robust in keeping the vehicle tracking the desired response quickly and correctly even under some parameters changed such as steering angle input, road friction and vehicle speed.In the end, Chapter 5, the scheme of simulation test, control prototyping experiment, Real-car test and the results of all stages is described in detail. Hardware & human in the loop simulation test bench is built with computer real-time simulation and virtual reality, it provides a bench for research of VSC theory, calibration and debug for control system development.The successful application of model based design and development method for the VSC development proved that it is a simple and effective way to develop vehicle electronic control system. The practice and study in this paper is useful for native vehicle electronic product development and research.