As one of the typical propulsion systems of the new-energy vehicles (NEVs), the dual-motor driving system (DMDS) is installed and fixed on the bodywork and moves together with the bodywork in space, that is, the DMDS works in non-inertial systems. The previous researches on the DMDS are based on the assumption that the bodywork is stationary. In fact, since the DMDS moves with the bodywork, besides its own excitation forces, it is inevitably affected by the additional inertial terms (AITs) caused by the change in the operating state of the NEVs. In order to investigate the dynamic response and synchronizing characteristic of the DMDS under different motion forms of NEVs, the dynamic model of the DMDS in a non-inertial system is established, considering the permanent magnet synchronous motors (PMSMs), time-varying meshing stiffness and transmission error of gears. Subsequently, the expressions of the AITs are deduced under different non-inertial conditions. The translational motion and circular motion of the vehicle are selected to analyze the dynamic response and synchronizing characteristics of the DMDS in a non-inertial system. The results show that the acceleration has a significant influence on the displacement response of gears, torque and speed of PMSMs, but the torque synchronization and speed synchronization between PMSMs are minimally influenced by both the acceleration and the AITs. Meanwhile, the AITs that affect the displacement response are analyzed and quantified.

Volumetric error decoupling is a critical prerequisite for effective error compensation. In this paper, the forward volumetric error model is established using the screw theory. Additionally, the Jacobian matrix based on the product of exponential is derived to construct the linear relationship between the volumetric error and the axis motion and decouple the volumetric error model. To address the limitation of compensation motion, a step-by-step decoupling method is proposed, where attitude and position errors are compensated sequentially. After detecting the actual geometric errors of the grinding machine, the volumetric error can be determined, and the compensation motion commands for each axis are calculated to correct the volumetric error. The simulation result shows that the mean value of the comprehensive error ranges can be reduced from 19.7 μm to 1.8 μm, demonstrating the effectiveness of the proposed method.

Magnetorheological fluid (MRF) coupling is commonly used in electric drive gear transmission systems (EDGTSs) due to its controllable stiffness and damping, which can enhance shock resistance and reduce system vibration. However, the vibration reduction performance of MRF coupling is affected by changes in operating temperature caused by factors such as coil thermal effects. Therefore, a mechanical-electromagnetic-thermal coupling dynamical model for EDGTS was established, including the driving motor, MRF coupling, and transmission gear. Then, comparative analysis was conducted on the variation laws of the system's coupled vibration characteristics with and without considering the operating temperature of the MRF coupling. The results show that the stiffness and damping of the MRF coupling decreased as the operating temperature increased, and their greatest reductions are 53.56 % and 33.41 % respectively when the current was 2.0 A and the operating temperature reached 90 °C. In addition, the vibration amplitude at each node of the EDGTS increased with the rise of operating temperature, and the growth rates of maximum vibration displacement amplitude range, vibration velocity root mean square (RMS) value, and maximum vibration acceleration are 27.87 %, 72 %, and 61.63 %, respectively.