Automatic Docking Method for Charging Connector of Electric Vehicle Based on Hybrid Force-position Compliance Control

Abstract

Aiming to solve the docking problems of an electric vehicle’s DC charging connector, including small fitting tolerance, large model difference, and uncertain position and pose, this paper proposes a flexible docking method for an automatic charging robot based on hybrid force-position control. In the proposed method, the automatic docking operation of a charging connector is divided into four stages. The contact stage includes single-and two-point contacts, and in this stage, a mechanical model of a charging connector is established. In addition, considering the requirements of practical applications, a hybrid force-position control model and a flexible docking method of a self-adaptive position are developed in the contact stage, and a complete control strategy is designed according to typical application requirements for the automatic docking of a charging connector. A test system is constructed to test the proposed hybrid compliance control method and compare it with the existing docking method without compliance control. The test results show that the proposed hybrid force-position compliance control method can stably comply with external constraints in the process of automatic docking of an electric vehicle’s charging connector and complete the docking. The maximum docking force in the Z-direction is reduced by 52.8%.