Automatic parking system for electrified vehicles using sonar sensors

Mitsubishi Electric has been developing an automatic parking system. The main part in the system is provisionally named e-Park controller. It executes PSM (parking slot measurement) using our sonar sensors to find a parking slot available. Simultaneously, the controller estimates states of the vehicle and calculates an optimal path to the parking slot. After the path planning, reference signals for our electric power steering and driving motor control systems are generated to track the path automatically. The parking can be executed externally using our device for the keyless entry system. For safety, the parking system also has an emergency braking function based on the sonar sensors and operation of the driver. This paper mainly focuses on the design of the path planning algorithm and the vehicle speed controller. The automatic parking system is verified in experiments.