The automatic charging of electric vehicles is an important but challenging problem. Recently, various charging robots are proposed for electric vehicles. Most previous researches do not pay enough attention to the robots’ load capacities. Actually, providing the charging connector with adequate pushing and/or pulling forces is vital to guarantee a reliable electrical connection, which is a key issue for charging robot design. In this paper, we present a novel serial-parallel robot for the automatic charging of electric vehicles. This robot is based on the 3 universal-prismatic-universal (3UPU) parallel mechanism and featured by high-load capacity. We firstly address the kinematic and static models of the proposed robot, then analyze its load capacity. It is shown that the robot’s maximum load capacity depends not only on the driving ability of the prismatic joints, but also on the robot’s structural parameters and the robot’s configuration. Finally, optimizations are made and results show that the robot’s load capacity along the desired trajectory has more than doubled. Results of this paper could be useful for the development of automatic electric-vehicle-charging devices.

In the present study, detailed comparative experiments on a heavy-duty diesel engine used in the world harmonized transient cycle (WHTC) and road spectrum reversely deduced cycle (RSRDC, which was derived from a road test) were carried out. Fuel consumption and gaseous and particulate pollutants, along with some engine operation parameters, were measured transiently; thus, specific emissions can be calculated. Results showed that the BSFC of WHTC and RSRDC was 201.8 and 210 g/kW·h, respectively, because the real road driving cycle (RSRDC) had wider operating point distributions and more points located in the low-efficiency zone relative to WHTC. Thus, WHTC operations exhibited higher raw CO (abundant CO formation needed a specific temperature threshold) and NOx but lower HC. Furthermore, with aftertreatment, all pollutants met the newest China regulation limit. Finally, transient emissions were analyzed in detail. Although the specific emissions of some pollutants were similar in value for both cycles, transient processes may largely be different. Therefore, the current study is meaningful, and we not only provide broad and detailed information but also directly compare two types of operations (one is a real road driving cycle) in the laboratory: this is rarely discussed in the literature.