In view of the current traffic criticism faced by urban construction and the quality development and personalized trend of future rail transit system, a new type of maglev rail transit system is proposed in this paper. The principles of the modules of train suspension guidance, linear drive and on-board communication are also introduced and analyzed in this paper. Additionally, the feasibility of train suspension structure is studied based on Ansoft Maxwell finite element simulation, which includes: under three-dimensional magnetic field, the static magnetic force of Halbach permanent magnet array is changed, and the safety and reliability of the permanent magnet suspension array are verified by comparing with the actual test vehicle sampling data; the critical stability characteristics of suspension structure under static magnetic field are proved by physical modeling. Therefore, the electromagnetic damping structure is introduced into the vehicle suspension frame to constitute the hybrid suspension control system of permanent magnet electromagnetic, and the hybrid suspension model is established, which proves that the hybrid suspension system has controllable observability. Finally, the linearized state feedback control strategy is designed for the single-point electromagnetic levitation ball system to simulate the compensation and regulation of the static magnetic field by the electromagnetic damping system. The excellent performance of the electromagnetic levitation ball also proves the feasibility and rationality of the electromagnetic control strategy. Compared with the traditional electromagnetic hybrid suspension system, this system realizes ''zero'' power suspension, and the energy consumption of train suspension is only consumed in the instant that the electromagnetic damping system is regulated. INDEX TERMS Medium and low speed maglev train, Halbach permanent magnet array, suspended magnetic suspension system, urban rail transit system.

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A permanent magnet suspension (PMS) magnetic levitation (Maglev) system consisted of magnetic rail magnets and carriage magnets are investigated for PMS Maglev vehicle. The characteristics of magnetic flux line and magnetic flux density distribution in the suspension gap region are analyzed by using finite element method. The results show that the Halbach Array stack structure generates strong sinusoidal periodic magnetic field in the suspension gap region. The size of Halbach Array permanent magnets stacked structure model was simulated and optimized, and the optimal size factor was obtained. In addition, a levitation force model describing the relationship between magnetic levitation force, permanent magnet size and levitation height was established by molecular current method. The correctness of the levitation force model is evaluated. Finite element simulation and experiment verify the validity of the levitation force model. The results show that the optimized Halbach Array permanent magnets can generate large suspension force and good stability, which is of great significance to improve the utilization rate of permanent magnet materials and save costs, and is conducive to the further development of permanent magnet maglev train. The study is useful for analysis and design optimization of maglev train. INDEX TERMS Magnet parameter optimization, Halbach permanent magnet array, permanent magnet suspension (PMS), static magnet levitation force.

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Continuous drive friction welding (CDFW) is an economical and productive method for joining similar metals. In this study, 45 # steel was joined via CDFW, and the material heat distribution, flow behaviour, flash formation and fracture mode were investigated via experiments and simulations. The bar was divided into three zones in the direction of radius (R), the R zone near the axis, the edge zone at the edge of the R and the 0.5 R zone between the R zone and edge zone. The maximum flow velocity and temperature of the joint first appeared in the 0.5 R zone, and as the friction continued, the maximum temperature moved to the edge zone, followed by flash. When the friction time was 9 s, the maximum tensile strength was 674 MPa, the fracture mode was the coexistence of ductile and brittle and the fracture location had an obvious boundary. Ductile fracture occurred in the R zone, and the flash took a lot of heat, brittle fracture occurred in the 0.5 R and edge zones. The maximum microhardness of the joint is 295 HV in the weld zone, and the microhardness decreased in the partially deformed zone. When the friction time was appropriate, the heat distribution was uniform and sufficient, and the grains exhibited a significant degree of dynamic recrystallisation refinement.