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The composition structure of high-speed pantograph is analyzed, which is transformed into a four-rod mechanism, and the relative motion relation and its position coordinate equations are built by constructing a kinematics model. Based on the equations of motion of pantograph and the simulation of motion pattern between elevation height and transverse deviation of bow head, angle of balance arm is obtained by programming and running program in Matlab. The main parameters which are affecting high-speed pantograph lateral offset and balance arm rotation angle are analyzed. The relevant parameters are optimized by using the sequential quadratic programming (SQP) algorithm in Matlab. We compare the results after optimization with the results before optimization. Finally, according to the optimized results, the pantograph is modeled in Solidworks. The pantograph model is imported into the finite element analysis software to load, and the displacement cloud diagram of the pantograph bow head is obtained, and compared with the theoretical value to verify the optimization results.

Compared with the traditional gear reduction mechanism of the asynchronous motor, the permanent magnet synchronous motor (PMSM) direct drive technology has obvious advantages and has attracted increasing attention. We analyzed the advantages of the PMSM direct drive technology and put forward the hollow shaft structure of the coupling to reduce the impact force of the wheel and rail, additional noise, vibration, and loss. We deeply studied the topology and mathematical model of the PMSM. To keep the maximum running speed unchanged, it is necessary to conduct a flux weakening control above the rated speed to increase the speed regulation range of the PMSM. To prevent frequent switching jitter at the transition point and smooth the transition between different weak magnetic fields, we designed a new flux-weakening controller to control the current. Simulation results have been presented to verify the proposed approach efficiency. Taking the PMSM system train on Suzhou Metro line 3 as an example, the on-site energy consumption test was carried out. The energy consumption of the PMSM direct drive and asynchronous motor gear mechanism was compared. The energy consumption of the PMSM direct drive is increased by 16.50%. The flexible plate coupling can alleviate the adverse effects of vibration and improve the reliability of train operation. Finally, we put forward the technical difficulties and challenges of the PMSM direct drive technology. We need to optimize the mass distribution of the direct drive bogie to improve the dynamic performance of the bogie, the heat dissipation conditions, and the accurate control of the PMSM. It will have reference value for the development of the PMSM direct drive in the future.

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Suspension is one of the important components of automobile products, and the smooth operation of the automobiles is closely related to the structure of the suspension. This paper studies the semi-active suspension control and its performance test by firstly introducing the suspension, then analyzing the neural network control basis and designing the single-chip control system, and finally formulating the performance evaluation criteria of suspension to evaluate its function. The performance of the semi-active suspension built on the basis of neural network control theory is better than that of the passive suspension and active suspension, so it can be promoted in the future application.