Research On Steering Control Strategy Of Automatic Vertical Parking System

With the constantly developing of modern technology and people’s life standard, the automobile industry has took a huge step forward. In order to reduce the great number of parking accidents which caused by complex parking environment and inexperienced drivers, automatic parking technology has become a hotspot and difficulty in the research of intelligent vehicle. This work put forward two complete solutions of automatic vertical parking from path planning and fuzzy control respectively.In the solution based on path planning, we divided vertical path planning into C-shaped and Y-shaped according to lateral distance. We gave the calculation method of critical lateral distance and the key points in two types of path planning. Real processes were clearly demonstrated. We built vertical parking experimental system on JOYEAR based on Infineon MCU XC164 to verify the feasibility of the path planning, and completed the related hardware and software debugging work. The system simply applied one ultrasonic sensor and wheel speed pulse sensor to collect environment information. When the master control unit finished off-line path planning, it communicated EPS system to realize the angle control through CAN network. Combining the gear with the brake action cues from the buzzer, the automatic parking control were finally completed.We used a stable system to conduct ultrasonic ranging experiments, parking space detecting experiments, and vertical parking experiments. The results showed that, this path planning of vertical parking had a good implementation for automatic vertical parking. within the range of the admissible tolerance.Combining drivers experience with fuzzy theory, a steering controller for automatic vertical parking was developed in the solution based on fuzzy control. Without path planning in advance, fuzzy controller simulated human thinking according to the vehicle’s position and posture information, and then output steering order to successfully parked the car. This process gave another way to realize vehicle parking. Otherwise, in order to better solve error accumulation problems caused by the noise of wheel speed sensor during actual automatic vertical parking, the kinematic model was optimized by EKF. In addition, an optimal kinematic model and a fuzzy steering controller were built in Simulink for the simulation of vertical parking. It was concluded that the fuzzy control were feasibly applied in automatic vertical parking, and the EKF had good adaptability with solving error accumulation in parking system.