| Intelligent driving technology has attracted more and more attention as the city traffic is becoming increasingly congested and the accident rate is higher and higher in modern society. Due to the limitations of real vehicle research and the idealization of pure software simulation, the thesis designs and builds a micro environment of hardware simulation platform according to the proportion of 10:1, which includes the micro vehicle and path.The vehicle uses electromagnetic sensor to obtain path information as the electromagnetic navigation system has many advantages like simple structure, few data and precise location, while the MC9S12XS128 is chosen as the MCU.According to functions, the experiment designs circuit schematics and PCBs of each module. Then it uses electromagnetic laws to analyze the magnetic path, and to arrange the sensors.In order to overcome the nonlinearity and hysteresis of steering system, this paper uses fuzzy control algorithm to control the servo. The output is continuous, stable, smooth and has no step, which is different from the simple look-up table method.Against to the inertia of motors, the PID algorithm is used to control them. It also designs a negative-feedback loop motor control system. In contrast to the non-PID control system, the speed is significantly stable and has more anti-interference ability.Some practical tests are carried out in the path. It shows that the vehicle can run smoothly across the right angle, the S-shape angle, etc. The speed is stable and has robustness. It turns out that the system has good control effect and certain application value. |
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