阅读说明：本技术 一种磁浮列车、悬浮控制系统及提高运行平稳性的方法 (Magnetic-levitation train, levitation control system and method for improving running stability ) 是由 舒瑶 杨颖� 蒋忠城 佟来生 张俊 张波 刘国云 陈晶晶 刘晓波 洪远卓 金淼鑫 于 2021-09-17 设计创作，主要内容包括：本发明公开了一种磁浮列车、悬浮控制系统及提高运行平稳性的方法,涉及悬浮控制领域。本发明针对轨道不平顺干扰对磁浮列车悬浮控制稳定性的影响,在获得不平顺干扰预估值后,运用前馈控制对轨道不平顺施加动态补偿,可大大削弱不平顺干扰对悬浮控制稳定性的不利影响,延长轨道养护维修的周期而降低运营成本,进一步提升磁浮列车运行的平稳性和舒适性。本发明通过增加前馈控制,提高了磁浮列车悬浮控制系统的抗干扰能力,提升了悬浮控制系统的鲁棒性和环境适应性,所采用的前馈控制与反馈控制策略,也可迁移用于其他相似的场景。(The invention discloses a magnetic-levitation train, a levitation control system and a method for improving running stability, and relates to the field of levitation control. Aiming at the influence of the track irregularity interference on the suspension control stability of the maglev train, after the irregularity interference estimated value is obtained, the feedforward control is used for dynamically compensating the track irregularity, so that the adverse influence of the irregularity interference on the suspension control stability can be greatly weakened, the track maintenance period is prolonged, the operation cost is reduced, and the running stability and comfort of the maglev train are further improved. The anti-interference capability of the suspension control system of the magnetic-levitation train is improved by adding the feedforward control, the robustness and the environmental adaptability of the suspension control system are improved, and the adopted feedforward control and feedback control strategies can be migrated and used in other similar scenes.)

1. A method for improving the running stability of a maglev train is characterized in that the control mode of a single-point suspension electromagnet comprises the following steps:

i, collecting the vertical acceleration and the suspension gap of the electromagnet and obtaining an estimated value delta h of the track irregularity_t(ii) a Designing a feedforward controller with a transfer function G_ff(s)＝-K_f(T_f1*s+1)/(T_f2*s+1)，K_fFor feedforward coefficients, T_f1And T_f2Is a time constant;

II, estimating the irregularity Δ h_tInput to the feedforward controller;

III, vertical acceleration and suspension clearance H of the electromagnet_tThe output of the single-point suspension electromagnet is added to the output of the feedback controller to obtain the displacement of the electromagnet;

IV, firstly setting parameters in the feedback controller, and then adjusting a feedforward coefficient K in the feedforward controller_fWith time constant T_f1、T_f2And (4) performing parameter setting until the oscillation amplitude of the electromagnet displacement is minimum.

2. The method for improving the running stability of the magnetic-levitation train as recited in claim 1, wherein the specific implementation manner of the step I comprises:

determining the position of the suspension electromagnet when the train is statically suspended, and recording the suspension gap reference H at the moment₀；

Recording the suspension gap H transmitted from the suspension sensor of the electromagnet at each time interval t_tAnd the vertical acceleration a of the electromagnet_ztCalculating the vertical dynamic displacement d of the electromagnet_t＝∫∫a_ztdtdt；

By the formula Δ h_t＝H_t-d_t-H₀Calculating the vertical irregularity estimated value delta h of the track_t。

3. The method for improving the running stability of the magnetic-levitation train as recited in claim 1 or 2, wherein the concrete implementation manner of the step III comprises;

setting a feedforward coefficient K_f: let time constant T_f1And T_f2Are all 0, when there is no feed forward control, the input current of the electromagnet is i₁Track irregularity value of d₁Obtaining the displacement of the electromagnet as y; keeping the displacement of the electromagnet unchanged as y and when the track irregularity value is d₂Regulating the input current of the electromagnet to i₂According to formula K_f＝(i₂-i₁)/(d₂-d₁) Calculating a feedforward coefficient;

setting a time constant: let T_f1>T_f2Gradually adjusting T based on the track irregularity estimate value delta ht_f1And T_f2The oscillation amplitude of the electromagnet displacement y is minimized.

4. A levitation control system comprising a computer device programmed or configured to perform the steps of the method of claims 1-3.

5. A magnetic levitation train comprising the levitation control system of claim 4.

Technical Field

The invention relates to the field of suspension control, in particular to a magnetic suspension train, a suspension control system and a method for improving running stability.

Background

The magnetic suspension traffic system is a complex electromechanical system integrating multiple disciplines of mechanical engineering, control engineering, civil engineering and the like, strong mutual influence exists among the systems, and the dynamic behavior of train operation is very complex. The maglev train depends on the electromagnetic force generated by the actively controlled electromagnet for suspension and guidance, and encircles a slender track beam under the propulsion of a linear motor, so that the direct mechanical contact between a vehicle and a track is avoided, but a large number of dynamics problems still exist. The magnetic suspension system has nonlinear active magnetic suspension force, so that the research on the dynamics of the magnetic suspension vehicle system has great particularity, and the development and the application of the magnetic suspension train are directly influenced by the stability of the magnetic suspension train control system and the running stability of the whole vehicle.

The whole magnetic suspension train system comprises a mechanical part and a control part, wherein the mechanical part comprises a magnetic suspension module and a train body, the control part comprises suspension, guidance, driving and operation control, and mechanical coupling and electromechanical coupling are quite complex. The suspension control technology is one of the core and key technologies of the magnetic-levitation train, and the quality of the performance of the suspension control system directly influences the stability, safety and comfort of the magnetic-levitation train. The most basic requirement of the control of the maglev train is to ensure that the maglev train can have balanced and stable suspension under various disturbance effects to a certain degree, and external disturbance acting on a suspension system mainly comprises load change, driving acceleration force and deceleration force, aerodynamic force and disturbance force caused by elastic bending and irregularity of a track. For the EMS type electromagnetic suspension system, the electromagnetic suspension is that a vehicle-mounted suspension electromagnet arranged below a guide rail is electrified and excited to generate an electric field, the magnet and a ferromagnetic component on the rail attract each other to attract a train upwards to suspend on the rail, and the suspension gap between the magnet and the ferromagnetic rail is generally 8-12 mm. The train ensures a stable suspension gap by controlling the exciting current of the suspension magnet, and the train is attracted by the attraction force of the magnetic field and the ferromagnetic body on the track and is suspended on the track with a gap of about 8-10 mm. And a sensor arranged on the electromagnet measures the suspension gap and the acceleration of the electromagnet in real time, and adjusts the coil current through a suspension control system to keep the suspension gap of the vehicle at a rated value.

For an electromagnetic levitation type train, the system itself is unstable, and in order to achieve levitation stability, a feedback control device must be used to control the voltage (current) by using the feedback of the levitation air gap. The traditional control mode is to linearize a nonlinear magnetic suspension model at a balance point and then perform feedback control on the linearized model, and with the continuous development of modern control theory, a plurality of advanced control algorithms are applied to the suspension control technology of the magnetic suspension train. Modern control methods such as adaptive control, fuzzy control, sliding mode structure control, robust control and the like of the maglev train are deeply researched. In the early 70 s of the 20 th century, students designed various classical control algorithms according to input conditions such as suspension gap change, speed and acceleration of gap change and the like, and in the last 80 s and 90 s of the century, various nonlinear control algorithms are widely applied to magnetic levitation control, such as H robust control, adaptive control, sliding mode variable structure control and the like, in order to enable a system to have good robustness and adaptability. As can be seen from the literature, the emphasis of current levitation control systems has shifted from pure stability design to robust and adaptive capability design of the systems. Such a transition is inseparable from the practical application background of magnetic levitation transportation technology; in order to put the magnetic levitation transportation technology into use formally, from the industrialization perspective, the running environment of the magnetic levitation vehicle is greatly changed in the future, and along with long-time operation, the settlement and the irregularity of the track line can be continuously developed, so that the controller is required to have stronger self-adaptive capacity and robustness so as to meet the requirement of the controller on the adaptability of the complex environment.

When a high-speed maglev train runs, if pure feedback control is utilized, the problems of difficult parameter setting, long adjusting time, large overshoot, poor interference resistance and the like exist, a feedback control system changes from interference to controlled quantity and generates corresponding control action according to deviation, then the change from a control signal to the controlled quantity needs a certain time, the feedback control always lags behind the interference action, namely the feedback control cannot overcome the interference before the controlled quantity deviates from a set value. The train can vibrate violently due to the fact that the track is not smooth caused by geometric deviation, tooth grooves, uneven settlement and the like of the stator face and the functional part, and the influence of the change of the geometric form of the track on the train operation is large under long-term operation. In fact, the track is not smooth and can not be avoided, and the maintenance of the track can only be regularly and frequently carried out, so that the operation cost is inevitably increased.

Disclosure of Invention

The invention aims to solve the technical problem that the defects in the prior art are overcome, and the magnetic-levitation train, the levitation control system and the method for improving the running stability are provided.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: magnetic suspension train, its suspensionIn the method for improving the running stability of the floating control system in the control program, the control mode of the single-point suspension electromagnet comprises the following steps: i, collecting the vertical acceleration and the suspension gap H of the electromagnet_tAnd obtaining an estimated value deltah of the track irregularity_t(ii) a Designing a feedforward controller with a transfer function G_ff(s)＝-K_f(T_f1*s+1)/(T_f2*s+1)，K_fFor feedforward coefficients, T_f1And T_f2Is a time constant;

II, estimating the irregularity Δ h_tInput to the feedforward controller;

III, vertical acceleration and suspension clearance H of the electromagnet_tThe output of the single-point suspension electromagnet is added to the output of the feedback controller to obtain the displacement of the electromagnet;

IV, firstly setting parameters in the feedback controller, and then adjusting a feedforward coefficient K in the feedforward controller_fWith time constant T_f1And T_f2And (4) performing parameter setting until the oscillation amplitude of the electromagnet displacement is minimum.

Aiming at the influence of track irregularity interference on the suspension control stability of the magnetic-levitation train, the irregularity estimated value delta h is obtained_tAnd then, the dynamic compensation is applied in the feed-forward control, the smaller the oscillation amplitude of the electromagnet displacement is, the closer the suspension clearance is to a rated value by combining the feedback control of the train, the adverse effect of the irregularity interference on the suspension control stability can be greatly weakened, and the anti-interference capability of the suspension control system is improved by increasing the feed-forward control, so that the running stability of the train is improved. Because the suspension control system of the whole magnetic suspension train is composed of a plurality of single-point suspension electromagnet control modules, the parameter adjustment of the whole train is difficult, the workload is large, the time is long, if the parameters are applied to all the single-point suspension electromagnets of the whole train after the parameter adjustment is carried out on the control module of a certain single-point suspension electromagnet, the parameters of certain single-point suspension electromagnets only need to be finely adjusted according to the actual conditions, the difficulty in parameter adjustment is reduced, and the workload and the working time for parameter adjustment are greatly reduced.

Specifically, the specific implementation manner of step I includes:

determining the position of the suspension electromagnet when the train is statically suspended, and recording the suspension gap reference H at the moment₀(ii) a Recording the suspension gap H transmitted from the suspension sensor of the electromagnet at each time interval t_tAnd the vertical acceleration a of the electromagnet_ztCalculating the vertical dynamic displacement d of the electromagnet_t＝∫∫a_ztdtdt; by the formula Δ h_t＝H_t-d_t-H₀Calculating the vertical irregularity estimated value delta h of the track_t。

Specifically, a specific implementation manner of step III includes;

setting a feedforward coefficient K_f: let time constant T_f1And T_f2Are all 0, when there is no feed forward control, the input current of the electromagnet is i₁Track irregularity value of d₁Obtaining the displacement of the electromagnet as y; keeping the displacement of the electromagnet unchanged as y and when the track irregularity value is d₂Regulating the input current of the electromagnet to i₂According to formula K_f＝(i₂-i₁)/(d₂-d₁) Calculating a feedforward coefficient;

setting a time constant: let T_f1>T_f2Based on the estimated value of track irregularity Δ h_tGradually fine-tuning T_f1And T_f2The oscillation amplitude of the electromagnet displacement y is minimized.

Compared with the prior art, the invention has the beneficial effects that: the method is simple, clear in principle, convenient in data acquisition and easy to implement, is suitable for large-scale popularization and application, and the data is sourced from the sensor of the electromagnetic suspension system, and the actual requirement is met. Aiming at the influence of the track irregularity interference on the suspension control stability of the maglev train, after the irregularity interference estimated value is obtained, the feedforward control is used for dynamically compensating the track irregularity, so that the adverse influence of the irregularity interference on the suspension control stability can be greatly weakened, the track maintenance period is prolonged, the operation cost is reduced, and the running stability and comfort of the maglev train are further improved. The anti-interference capability of the suspension control system of the magnetic-levitation train is improved by adding the feedforward control, the robustness and the environmental adaptability of the suspension control system are improved, and the adopted feedforward control and feedback control strategies can be migrated and used in other similar scenes.

Drawings

FIG. 1 is a schematic diagram of a method for improving operating stability according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of track irregularity according to an embodiment of the invention.

Fig. 3 is a schematic diagram of a single-point levitation electromagnet control dynamics model according to an embodiment of the present invention.

Fig. 4 is a diagram of a magnetic levitation train model according to an embodiment of the present invention.

FIG. 5 is a block diagram of feedforward control and feedback control in a simulation experiment according to an embodiment of the present invention.

Fig. 6 shows a floating gap without interference in a simulation experiment according to an embodiment of the present invention.

Fig. 7 shows a floating gap under the condition of the non-smooth interference in the simulation experiment according to the embodiment of the invention.

FIG. 8 is a diagram illustrating the suspension clearance after feedforward control compensation in a simulation experiment according to an embodiment of the present invention.

The system comprises a magnetic levitation train dynamic model, a magnetic levitation frame model, a single-point levitation point model, a levitation electromagnet model, a magnetic levitation train dynamic model, a first switch and a second switch, wherein 1 is an electromagnet, 2 is a track, 3 is a track stator surface reference line, 4 is an inertia reference line, 5 is a track model in the single-point levitation electromagnet control dynamic model, 6 is an electromagnet model in the single-point levitation electromagnetic control dynamic model, 7 is a train body model in the magnetic levitation train dynamic model, 8 is a levitation frame model in the magnetic levitation train dynamic model, 9 is a single-levitation point model in the magnetic levitation train dynamic model, 10 is a levitation electromagnet model in the magnetic levitation train dynamic model, S1 is a first switch, and S2 is a second switch; h₀For the levitation gap reference, H_tA suspension gap from the electromagnet suspension sensor_ztIs the vertical acceleration of the electromagnet.

Detailed Description

In the magnetic levitation train of an embodiment of the invention, the levitation control system comprises a plurality of control modules of single-point levitation electromagnets, and the method for improving the running stability in the control modules of the single-point levitation electromagnets comprises calculation of rail irregularity estimated values and levitation feedforward control and feedback control, wherein the levitation feedforward control and the feedback control are completed by a levitation controller and a feedback controller, and the feedback control can be referred to in the literature "zhazanwaning, Zhao, magnetic levitation vehicle/rail system dynamics (I) -magnetic/rail interaction and stability [ J ]. mechanical engineering reports, 2005(07): 5-14".

The track irregularity estimated value is calculated based on the suspension gap and electromagnet acceleration data of the electromagnetic suspension system during the last running of the magnetic-levitation train, and the track irregularity estimated value is obtained through time domain calculation. And the suspension feedforward control and the suspension feedback control apply feedforward control and feedback control on electromagnetic suspension according to an irregularity estimated value obtained in the last operation, so that the influence of random irregularity interference on the running stability and comfort of the train is reduced.

The method for calculating the track irregularity estimation value comprises the following steps:

first, as shown in fig. 2, the position of the levitation electromagnet when the train is statically levitated is determined, and the levitation gap reference H at that time is recorded₀；

Secondly, recording the suspension gap H transmitted from the suspension sensor of the electromagnet at each time interval t_tAnd the vertical acceleration a of the electromagnet_ztCalculating the vertical dynamic displacement d of the electromagnet_t＝∫∫a_ztdtdt；

Finally, by the formula Δ h_t＝H_t-d_t-H₀Calculating the vertical irregularity estimated value delta h of the track_t。

The suspension feedforward control and feedback control method is carried out in a simulation experiment and comprises the following steps:

firstly, a single-point suspension electromagnet model is established by utilizing multi-body dynamics software, and a feedback type suspension control module is established based on the existing feedback control to obtain a single-point suspension electromagnet-control dynamics model, as shown in fig. 3, the single-point suspension electromagnet-control dynamics model comprises a track model 5 and an electromagnet model 6, and a suspension gap H is introduced between the track model 5 and the electromagnet model 6_tAs a control actionAs a result, when there is a control force between the track model 5 and the electromagnet model 6, the levitation gap H_tThe change occurs.

Secondly, designing a feedforward controller, wherein the feedforward controller is designed by adopting dynamic feedforward control with a transfer function of G according to an empirical method because the design and parameter theory setting of the feedforward controller are very difficult_ff(s)＝-K_f(T_f1*s+1)/(T_f2*s+1)，K_fFor feedforward coefficients, T_f1And T_f2Is a time constant; on the basis of the existing feedback control of the maglev train, dynamic compensation aiming at track irregularity is applied in advance, the output of the feedback control and the output of the feedforward control are added to be used as the input of a single-point suspension electromagnet, and irregularity interference is overcome before a suspension gap deviates from a set value;

the parameter setting of the feedforward control and the feedback control is carried out according to the steps of setting the feedback control firstly and then setting the feedforward control, the parameter setting of the feedback control is according to the engineering setting method in the prior art, and the reference can be made to the following documents: liu Ru, a magnetic suspension train suspension system PID self-tuning control research [ D ]. Sichuan, southwest traffic university, 2007, then on the basis of feedback control for completing parameter tuning, feedforward control is introduced, and parameter tuning is carried out on the feedforward control system. The method for determining the parameters of the feedforward controller adopts an engineering setting method, the setting of a feedforward control system is divided into two steps of static feedforward coefficient setting and time constant setting, the static feedforward coefficient is adjusted step by step to reduce the oscillation amplitude of the output of the system, and then the time constant is set on the basis.

The parameter setting method specifically comprises the following steps:

setting the feedforward coefficient K first_f: let time constant T_f1And T_f2Are all 0, when there is no feed forward control, the input current of the electromagnet is i₁Track irregularity value of d₁Obtaining the displacement of the electromagnet as y; keeping the displacement of the electromagnet unchanged as y and when the track irregularity value is d₂Regulating the input current of the electromagnet to i₂According to formula K_f＝(i₂-i₁)/(d₂-d₁) And calculating a feedforward coefficient.

In practical applications, y is obtained by direct measurement, which can be found in the magnetic levitation train, wuxiangming, shanghai science and technology press 2003. In the simulation experiment, the acquisition mode of y is as follows: under the condition that the electromagnet model 6 is in a non-input state, measuring that the distance between the track model 5 and the electromagnet model 6 is y₁The input to the electromagnet model 6 is i₁Then, the distance between the track model 5 and the electromagnet model 6 is measured as y₂By the formula y ═ y₁-y₂And y is calculated.

Re-setting the time constant: let T_f1>T_f2Based on the estimated value of track irregularity Δ h_tGradually fine-tuning T_f1And T_f2The oscillation amplitude of the displacement of the electromagnet is minimized.

And finally, establishing a maglev train-control model by utilizing multi-body dynamics software, simultaneously establishing a feedforward control and feedback type suspension control module of the whole vehicle, combining a plurality of single-point suspension electromagnet-control dynamics models to obtain the maglev train-control dynamics model, applying parameters in the single-point suspension electromagnet-control dynamics model to the maglev train-control dynamics model, and carrying out fine adjustment according to a simulation result.

The parameters obtained in the simulation are applied to a control system of the whole entity maglev train, and fine adjustment is carried out according to actual conditions, so that the stability of the maglev train in the running process can be improved.

In the simulation, the maglev train model is shown in fig. 4 and comprises a train body model 7, four suspension frame models 8, seven suspension electromagnet models 10 and twenty-eight single suspension point models 9.

The maglev train-control model is shown in fig. 5, and comprises feedforward control realized by gff(s) and feedback control realized by PID, and the track irregularity estimated value is simulated by white noise. Opening the first switch S1 and the second switch S2, with no disturbance to the levitation gap result as in fig. 6; closing the first switch S1, the result of simulating the levitation gap under the track irregularity disturbance is fig. 7; the result of introducing the feedforward control, i.e. closing the second switch S2, simulating the levitation gap under the combined effect of the track irregularity disturbance and the feedforward control compensation is shown in fig. 8. Fig. 8 is almost identical to fig. 6, and it can be seen that the method of the present invention has a good effect of compensating for the track irregularity interference.