With the help of several in-wheel motors, four-wheel independent-drive electric vehicle (4WIDEV) has tremendous potential to improve vehicle performance. Except for the theme of stability enhancement during the past two decades, energy saving topic becomes more attractive recently. However, it is difficult to achieve stability and economy performance simultaneously. Given the commonly used control method of rigid yaw rate tracking may limit the energy saving potential of 4WIDEV in cornering. Therefore, be different from previous studies which often focus on a sole target, in this paper, a driving energy management strategy for 4WIDEV based on multi-objective online optimization of four-wheel torque distribution is proposed in this paper, which includes weighted yaw rate tracking error into its parameterized control objectives besides electric drive system efficiency, tire slip losses and wheel torque ripple. Meanwhile, for better coordination of stability and economy in different situation, fuzzy logic control is adopted to dynamically adjust the weight of the control objective indexes of the proposed multi-objective online optimization function. Then, a particle swarm optimization algorithm is adopted to solve the optimization function. Finally, the proposed strategy for energy-efficient driving is verified based on the built Simulink and CarSim co-simulation model. The results show that the proposed four-wheel torque distribution strategy based on the multi-objective online optimization is more effective than average distribution strategy and offline optimization strategy.

Closed hydrostatic guideway has problems of high part processing difficulty, difficult assembly, etc. Part processing difficulty and assembly process of hydrostatic guideway with two structures are comparatively analyzed for determining rational structure form of hydrostatic guideway. Size structure of hydrostatic guideway is designed according to actual load of guideway and stroke demand situation. Processing technology route of parts of parts of hydrostatic guideway are provided. Linear precision and load capacity of hydrostatic guideway are tested. The results show that the hydrostatic guideway stroke is 240mm, linear operation precision within the stoke scope is 0.7 mu m, it reaches the design requirements, and technical support is provided for development of precision machine tool.

By using the information entropy theory, a solution to Weibull-small sample prior distribution of system reliability is proposed, which aims at solving the reliability estimation of high-end CNC. Firstly, the prior information is converted from subsystem level into system level based on entropy theory. Then, the prior distribution is solved with the constrained maximum entropy method. Finally, multi-information is fused based on the entropy weighs. It is proved by a case example that this method can obtained the prior distribution under Webull-small sample effectively.

Improving the reliability of linear motor is one of the best ways to improve its quality and performances. The core in reliability test is to simulate the dynamic loading as real operating condition. In this paper, a common loading model, which can reflect various operating conditions of linear motor, is proposed. Then a set of dynamic loading method for reproducing the operating conditions is put forward. This method completes dynamic loading against linear motor simutaneously in its moving and non-moving directions using servo control contact method and magnetic non-contact method, respectively. This research provides not only a set of feasible method for linear motor reliability test in lab, but also a prerequisity for studying linear motor reliability further.

In order to accurately emulate the operation conditions of high-speed motorized spindle in the reliability experiment, a dynamic loading system is proposed. This system allows simultaneously loading torque, radial and axial force against the spindle. The torque load is carried out by the electric dynamometer; the non-contact vibration exciter completes the radial load; the axial load is carried out by a self-made electromagnet. Moreover, this system also can detect out the basic features and failure data of the motorized spindle during the loading. And these sampling data provide a quantitative elevation for its reliability analysis. This paper presents a simple solution to the high-speed motorized spindle reliability research where the loading experiment is designed with the spindle whose maximum rotational speed is 18000rpm.