Research On Automobile Cruise Control System Based On DSP

With the development of automobile dustry and carrying trade, automobile will be more and more widespread. More comfortable, more convenient and safer vehicle will be needed. Automobile cruise control system (CCS), which not only could relieve the drivers'burden but also could make the driving comfortable, is a kind of accessorial driving system. Cruise control system has high nonlinearity and nondeterminacy with time changing. And CCS, which is effected by some factors such as external load disturbers and complicated running modes, will not have a good running effect with the traditional PID control. A kind of CCS which is based on Fuzzy PID control is introduced in the thesis.First, the background of cruise control system and its status and developing trend is expatiated on in the dissertation. The composing of CCS is also introduced in detail. The principium of CCS is described by analyzing a kind of closed loop system.After analyzing the cruise control system briefly, Fuzzy-PID is confirmed as the control method of the system. Then the Fuzzy PID controller is designed. As the object is a car, the thesis analyzes the resistances and disturbs while the car's running. And the automobile dynamics model is given. After setting up the model by means of MATLAB/Simulink, the result is analyzed. From the result, we may know that Fuzzy PID control could make the overshoot smaller and the response time shorter. The effect of Fuzzy PID method is good, so it is a suitable method for CCS.The design of the system is presented from hardware and software particularly. In the aspect of hardware, a design scheme based on TMS320LF2407A chip is introduced. The design principles of some circuits are analyzed particularly, and circuit diagram is given accordingly. In the aspect of software, the design scheme of programme is given considering the characteristics of DSP. The main flowchart and some subprogram flowcharts are also given.Finally, the system is debugged on the automobile cruise control system dais, which is based on the accomplishment of its hardware circuit board and software programming. The result of the test shows that the system could execute some simple orders ideally.