Levitation mechanism modelling for maglev transportation system

A novel maglev transportation system was proposed for large travel range ultra precision motion.The system consists of a levitation subsystem and a propulsion subsystem.During the propulsion subsystem driving the moving platform along the guideway,the levitation subsystem uses six pairs of electromagnets to steadily suspend the moving platform over the guideway.The model of the levitation system,which is a typical nonlinear multi-input multi-output coupling system and has many inner nonlinear coupling characteristics,was deduced.For testifying the model,the levitation mechanism was firstly controlled by proportional-integral-differential(PID) control,and then a lot of input-output data were collected for model parameter identification.The least-square parameter identification method was used.The identification results prove that the model is feasible and suitable for the real system.

Vibration analysis of maglev three-span rigid frame bridge considering magnetic force

The dynamic interaction between the maglev vehicle and the three-span rigid frame bridge is discussed. With the consideration of magnetic force, the interaction model is developed. Numerical simulations are performed to study the dynamic characteristics of the bridge during vehicle movement along the bridge. The results show that a reasonable value of the linear stiffness ratio of columns to beams is between 2. 0 and 3.0. The dynamic responses of the bridge are aggravated with the decrease in bending rigidity and the increase in vehicle speed and the span ratio of the bridge. It is suggested that a definite way is to control impact coefficients and acceleration in the dynamic design of the bridge. It is unsuitable to adopt the moving load model and the moving mass model in the design. The proposed results can serve in the design of high-speed maglev three-span rigid frame bridges.

Vibration analysis of maglev three-span continuous guideway considering control system

The dynamic interaction between maglev vehicle and three-span continuous guideway is discussed. With the consideration of control system, the dynamic interaction model has been developed. Numerical simulation has been performed to study dynamic characteristics of the guideway. The results show that bending rigidity, vehicle speed, span ratio and primary frequency all have important influences on the dynamic characteristics of the guideway and there is no distinct trend towards resonance vibration when fl/（v/l） equals 1.0. The definite way is to control impact coefficient and acceleration of the guideway. The conclusions can serve the design of high-speed maglev three-span continuous guideway.

Vibration Analysis of Continuous Maglev Guideway Considering the Magnetic Levitation System

The dynamic interaction between moving vehicles and two-span continuous guideway was discussed. With the consideration of the magnetic levitation system, the maglev vehicle/guideway dynamic interaction model was developed. Numerical simulation was performed to understand dynamic characteristics of the guideway used in practice. The results show that vehicle speed, span length and primary frequency of the guideway have an important influence on the dynamic responses of the guideway and there is no distinct trend towards resonance vibration when fl equals 1.0. The definite way is to control the impact coefficient and acceleration of the guideway. The conclusions can serve the design of high speed maglev guideway.

Electromagnetic characteristic analysis and design of a linear motor used for ultra-high-speed EMS maglev train

The operating speed of the commercial electromagnetic suspension(EMS)maglev train has been over 430 km/h,making it the fastest means of land transportation.With the increasing demands of people traveling,it is necessary to further improve the operating speed of maglev trains.Aiming to examine whether the existing EMS system can meet the requirements of ultra-highspeed operation(more than 600 km/h),the electromagnetic characteristics of an EMS linear motor under the operating speed of 600–1000 km/h fed by a square-wave voltage supply is investigated in this article.First,an electromagnetic field model of the EMS system under the square-wave voltage supply is established to investigate its electromagnetic performance,e.g.,the characteristics of phase current,the magnetic flux density,and the electromagnetic force.Second,the relationship between the harmonic components of the air-gap magnetic flux density and electromagnetic force is investigated using the two-dimensional fast Fourier transform(2D-FFT)to reveal the mechanism of electromagnetic force ripple.Third,to address the issues of excessive armature current density and significant electromagnetic force ripple,the linear motor is re-designed by enlarging the stator slot area and reshaping the mover's main magnetic poles.Furthermore,the Taguchi method is used to further improve the electromagnetic characteristics of the linear electric motor.Finally,the effectiveness of the proposed optimal design is validated by the finite-element analysis(FEA)based co-simulation.

Adaptive fault-tolerant control of high-speed maglev train suspension system with partial actuator failure: design and experiments

High-speed maglev trains will play an important role in the high-speed transportation system in the near future.However,under the conditions of strong magnetic fields and continuous operation,the actuators of the high-speed maglev train suspension system are prone to lose partial effectiveness,which makes the suspension control problem challenging.In addition,most existing fault-tolerant control(FTC)methods for suspension systems require linearization around the equilibrium points during the controller design or stability analysis.Therefore,from a practical perspective,this study presents a novel nonlinear FTC strategy with adaptive compensation for high-speed maglev train suspension systems.First,a nonlinear dynamic model of the suspension system based on join-structure is established and the actuator failures are described.Then,a nonlinear fault-tolerant suspension control law with an adaptive update law is designed to achieve stable suspension against partial actuator failure.The Lyapunov theory and extended Barbalat lemma are utilized to rigorously prove the closed-loop asymptotic stability even if there is partial actuator failure,without any approximation to the original nonlinear dynamics.Finally,hardware experimental results are included to demonstrate the effectiveness of the proposed approach.