Mechanism Designs of a Robot for Charging Multiple Electric Vehicles

Abstract Automobile industry is experiencing a major transformation into the era of electric vehicles. General Motors Global Research and Development Center developed a concept robotic system to charge multiple electric vehicles. This work demonstrated the process of designing the optimal robot mechanisms that can fulfill the functionalities of this system. Due to the application specific constraints, this system demands a robot that can cover a very large workspace, enter narrow gaps between parked vehicles, and reach vehicle inlets at a large height span at the same time. To navigate among a large number of potential mechanism options and to identify the optimal designs without the overuse of actuators, a Key DOF was proposed for this application and the design process was unfolded based on the different realizations of the Key DOF. Our results showed that the system might have limited applications when using a 5 degree-of-freedom robot. Redundancies were evaluated for their benefits in this application. The first redundant joint could be used to achieve the long-range travel in the parking lot drive aisle direction. This redundancy enabled many designs and two were recommended for the application towards different volumed products. Additional redundancy in the robot mechanism didn’t bring in enough benefits for the application to justify the increase in cost and complexity.