Research On Charging System Of Electric Vehicle And Its Automatic Plug In Based On Robot

With the gradual promotion and use of electric vehicles, its’ supporting infrastructure needs to be vigorously developed. At present, the use of charging facilities are dependent on manual operation, especially for the electric car rental, which can’t provide a good experience for users, and there is a security risk. If automatic operation in the electric vehicle charging can be realized, it can reduce the staff and lower labor intensity, cut down the management cost of charging station, improve the automation degree of charging facilities, and greatly promote the experience and operation safety for user. Combined with the application of the common and reliable technology, a series of research on automatic charging system is done, aims to develop a set of automatic charging system for electric vehicle,which can be operated automatically, stable and reliable, and has sound function and is suitable for popularizing in the city.The hardware equipment of the electric vehicle automatic charging function is studied. The implementation scheme of the system is selected and the hardware setup is completed.Taking the binocular vision sensor as the positioning device, the robot as the execution mechanism in automatic charging, and the industrial control computer is used as the control center of the system. According to the function requirements of the system operation, the external control circuit is designed to realize power supply, equipment protection, operation control and other functions of the system.Based on analysis of the kinematics of the robot, trajectory planning during the automatic insertion is completed rationally, the internal data receiving and trajectory planning program of the robot is accomplished. Through analysis of the automatic inserting process, the controlling strategy of in inserting is formulated. Impedance control method is adopted to realize force control of the robot so as to complete the adjustment of its posture, which prevent the blocking problem of the plug in process effectively.The hardware communication protocol of the system is studied and analyzed. The software design of the control center for the electric vehicle automatic charging system is completed, which includes the communication module with the vision sensor, the communication module of the robot and the module of GPIO program and so on. The communication and data transfer among the control center, the vision sensor and robot are realized, as well as the acquisition and control of the system’ state.The hardware installation and debugging are completed. After doing experiment on the precision of the visual sensor, the automatic plug in and force control of the robot, the accuracy of the visual sensor is verified. The results show that the use of impedance control force control strategy meet the precision requirements of automatic plug in quite well. It can be used to realize the automatic charging without manual operation after the parking of the electric vehicle, which provides the theoretical and experimental basis for its application.