Research On EPS Control Algorithm And DSPACE Real-time Simulation

With the higher request of environment protection, and greater demand of vehicle handling and comfort, power steering is used more and more widely in automotive industry.. Since 1953, the first hydraulic power steering system was used in Cadillac and Buick in General Motor, power steering technology has been developed more than 50 years. It experienced three phase: Electric Hydraulic Power Steering, Electric Power Steering (EPS) and Steer by Wire. Moreover because of the advantage of the technology and superiority of the performance, EPS will be sure to become the most widely used power steering system currently.There are two parts of the EPS design, software design and hardware design. These two parts are interactional, and the software design is more important. Although there are many domestic research departments and universities taking part in the EPS development, the software design capability is still weak. Therefore a systematic method for the EPS system modeling, analyses, simulation, and rapid control prototype based on dSPACE, is especially important.In this paper, The EPS model is built, and the performance is tested in the simulation. These modeling and simulation method include two parts below. Firstly, the EPS nonlinear model is built in Matlab/simulink, and then the current closed-loop control and current ficed-point algorithm are designed on it. Secondly, the three immportant control modes, such as essential assistance mode, return control mode, and damp control mode, are discussed in this paper. A closed-loop PID control and a sliding mode control (SMC) were built. The simulation results show the practicability of the two algorithms, and the difference of the PID and SMC control algorithm.Another aspect of this paper is the hardware development for EPS test. A test-bed is designed and built up,being used for the EPS performance test. A rapid control prototype for the current used EPS control algorithm was built, based on the dSpace system. The hardware test makes the primary validation for the control algorithms above.The research technique and conclusion could be helpful to establishing the dynamics model, configuration of the structural parameter and develop the product of EPS. Indeed the rapid control prototype method is very useful in the field of EPS development, and even in other electronic control units of automobile.