基于DSP的论文

电动汽车ABS控制半实物

仿真系统设计

Design of The Hardware-in-the-loop Simulation System for ABS Control in

Electric Vehicle

学院：电气工程学院

专业班级：自动化0802

学号：080302035

学生姓名：刘潇

指导教师：丁惜瀛（教授）

2012 年06 月

摘要

作为一种有效的汽车主动安全装置，电动汽车防抱死制动系统(ABS)能够在电动汽车制动过程中通过对四个车轮制动力矩的自动调节来防止车轮抱死，并使四个轮的滑移率维持在最佳滑移率附近，从而提高了汽车的制动效果以及方向稳定性。

传统ABS控制研究采用Matlab/Simulink数学仿真，置信度有限，而对车辆进行路面制动试验受许多条件的限制。硬件在环仿真技术能够根据实际情况建立基于真实硬件设备的模型代替原仿真系统的部分数学模型，大大缩短了控制器的开发周期和开发成本，并且比理论模型具有更高的可靠性，因此更适用于电动汽车ABS研究。

为了改进传统ABS系统的局限性，进一步提高电动汽车制动系统的性能，本文在综述国内外相关文献的基础上，对基于滑移率的ABS控制半实物仿真系统进行了关键技术的分析和实现方法的研究，主要包括以下几个方面：

第一，ABS控制器结构及控制原理研究。在深入研究汽车制动系统、ABS的工作原理及其性能指标的基础上，对ABS控制进行理论分析，并确定了基于滑移率的PID 控制算法。

第二，电动汽车ABS控制实半实物仿真平台的设计。基于xPC Target实时仿真系统，搭建ABS控制硬件在环仿真平台，硬件控制器采用TI公司的定点式32位DSP芯片TMS320F2812。宿主机中的整车数学模型通过TCP/IP通讯协议下载到目标机中，设计合适的通讯接口实现目标机与DSP的同步通讯。

第三，PID算法的C程序设计。建立CCS v3.3工程文件，主程序完成初始化功能，PID控制算法在外部中断服务子程序中实现。

第四，程序调试及仿真实验。在CCS环境下调试程序，整定PID参数，实现滑移率的控制。在不同初始条件下进行仿真，比较滑移率的控制效果，得出结论。

关键词：电动汽车；硬件在环；xPCTarget；DSP；ABS；PID控制

Abstract

As an effective vehicle active safety device, the electric vehicle Anti-lock Braking System (ABS) can automatically control the brake torque of each wheel to prevent it from getting locked in the process of braking, and maintain the wheel slip ratio near the optimal slip ratio. Thus, it improves the braking performance and directional stability of vehicle.

At present, the traditional research of ABS control uses mathematical simulation under the environment of Matlab/Simulink, where the confidence level is limited. And the brake test of electric vehicle on road is restricted by a number of conditions. The hardware-in-the-loop simulation technology, which replaces the mathematical model in the simulation system, is more reliable than theoretica l models. What’s more, it has a shorter development cycle and lower costs. So, it is more suitable for the study of electric vehicle ABS.

In order to obtain higher braking efficiency, a study on hardware-in-the-loop simulation of ABS control based on slip ratio has been investigated after reviewing relevant research literatures, focusing on its key technology as well as realization algorithms. The research scope of this paper is illustrated as follows:

First, the research of ABS controller structure and control theory. The electric vehicle braking system, ABS working principle and performance are deeply studied. PID control algorithm based on the slip rate is chose for the ABS control.

Second, the design of Hardware-in-the-loop Simulation System for ABS control in Electric Vehicle. Based on xPC Target, the system uses TMS320F2812 which is a 32 bits fixed-point DSP of TI as the hardware controller. Mathematical model of electric vehicle in HostPC is downloaded to the TargetPC via TCP/IP. An appropriate communication interface is designed to achieve synchronous communication between TargetPC and DSP.

Third, the build of a project for ABS control in CCS v3.3. PID algorithm is compiled in external interrupt Subroutine.

Fourth, program debug and simulation test. Debug programs and tune PID parameters in CCS v3.3. Simulations are conducted under different initial conditions. Different performances of slip ratio control are compared to draw the final conclusion.

Keywords: electric vehicle; hardware-in-the-loop; xPCTarget; DSP; ABS; PID control