Research On Control Strategy And Objective Evaluation Of ESP Based On Hardware-in-loop Simulation

ESP(Electronic Stability Program) is an important electronic system for vehicle, which can improve vehicle’s stability and safety. The V shape development process has become mainstream development method of automotive electronic control system, Hardware-in-loop simulation is an important part of ESP development process. ESP Hardware-in-loop simulation is not affected by the weather and avoids the risk of vehicle test under extreme conditions, therefore, it’s very necessary for the design and evaluation of ESP control strategy to develop an ESP Hardware-in-loop test bench with high performance. ESP objective evaluation and the design of ESP control strategy are inseparable, ESP objective evaluation plays guiding role for the design of control strategy. But the current ESP objective evaluation system is not perfect, the ESP control effect needs to be improved. In order to improve ESP control effect and perfect ESP objective evaluation, this paper studies ESP control strategy and objective evaluation through Hardware-in-loop simulation method.After analyzing and summarizing current research status of ESP control strategy and objective evaluation at home and abroad, this paper makes a research on ESP control strategy and objective evaluation based on Hardware-in-loop test bench. The research work of this paper contains the following aspects:(1) Designing and building ESP Hardware-in-loop test bench. After investigating the structure and working principle of ESP Hardware-in-loop test bench at home and abroad, this paper put forward the scheme of ESP Hardware-in-loop test bench. In this scheme, the ESP Hardware-in-loop test bench consists of three parts, which are driving simulator, brake test bench and the operation desk. This paper illustrates the working principle of the three part, the selection principle of main components is also studied in this paper.(2) Designing of ESP control strategy. Vehicle dynamics model is built and simulation conditions are set in Car Sim software. Front and rear axle’s equivalent lateral stiffness of two degrees freedom reference model is identified based on the genetic algorithm. In order to improve the robustness of ESP control strategy, one dimension fuzzy controller with multiple input variables is built to calculate the ideal yaw moment. The bottom level strategy of ESP is also studied in this paper.(3) Study of ESP objective evaluation system. As the ESP objective evaluation index is not rich, an objective evaluation index is introduced based on phase plane analysis, which enriches the traditional ESP evaluation index. After analyzing common ESP evaluation conditions, from the point of reviewing ESP function, this paper selects sine with dwell test, circle test, fishhook test, double lane change test and slalom test as the ESP evaluation test. Then the corresponding evaluation index of each test is determined, the ESP objective evaluation system is formed. The objective evaluation system can be used to evaluate the control strategy at Hardware-in-loop simulation stage, it will be reference for the objective evaluation at vehicle test stage.(4) Carrying out ESP Hardware-in-loop test and evaluating ESP control strategy. According to the ESP objective evaluation system put forward in this paper, each ESP evaluation test is carried out on test bench. Test data when ESP is on and off is extracted according to the evaluation index, and ESP control strategy is evaluated based on the extracted data. The evaluation results show that ESP developed by this paper improves the vehicle’s handling stability and it can effectively cope with various destabilizing conditions. Finally, the function of ESP Hardware-in-loop test bench is also verified.