Composite control method of maglev train suspension system based on cascade disturbance observer

Abstract

The present invention discloses a composite control method for a maglev train suspension system based on a cascade disturbance observer, and belongs to the field of suspension control technology. The method comprises: constructing a control model of a maglev train suspension system; constructing a cascade disturbance observer for estimating unknown state quantities, wherein the cascade disturbance observer comprises a matching disturbance observer and a non-matching disturbance observer; designing a composite controller, comprising a first controller for matching disturbance suppression and a second controller for compensating non-matching disturbances as a control target, wherein the first controller outputs a first control law, and the second controller outputs a second control law; and integrating the first control law and the second control law to coordinately control the maglev train suspension system by dynamically adjusting the electromagnet current. The present invention introduces non-matching disturbance compensation, so that the train can achieve rapid convergence under external complex disturbances, and effectively reduces the influence of external disturbances with complex action mechanisms such as aerodynamic excitation and line unevenness on the stability of the maglev train.

Description

Technical Field

[0001] The invention relates to the field of suspension control, and more specifically to a composite control method of a maglev train suspension system based on a cascade disturbance observer. Background Art

[0002] Maglev transportation has the advantages of high speed, low noise, strong climbing ability and strong curve negotiating ability. It overcomes the problems of traditional wheel-rail transportation such as speed limitation due to adhesion and mechanical wear, and is an important development direction of future rail transportation.

[0003] In the prior art, the magnitude of the electromagnetic force in the control process of the suspension system of the conventional electromagnetic high-speed maglev train is inversely proportional to the square of the suspension gap, and the equivalent capacitance and equivalent inductance of the electromagnet winding change with the suspension gap and time, which has significant nonlinearity. It can be seen from the characteristic polynomial of the electromagnetic suspension system that this system has open-loop instability, and as the speed increases, the vibration effect of track unevenness, the time lag effect of the suspension system, and the influence of aerodynamic force are aggravated.

[0004] In summary, the current high-speed maglev train suspension system has significant instability, so the suspension controller needs to be further improved to overcome the influence of various disturbances on the control. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a composite control method for a maglev train suspension system based on a cascade disturbance observer, which can suppress the influence of external disturbances on the suspension system.

[0006] According to a first aspect of the present invention, a composite control method for a maglev train suspension system based on a cascade disturbance observer is provided, comprising the following steps:

[0007] Construct a control model of the maglev train suspension system, which contains unknown state variables;

[0008] Constructing a cascade disturbance observer for estimating the unknown state quantity, the cascade disturbance observer comprising a matched disturbance observer and a non-matched disturbance observer;

[0009] Designing a composite controller, including a first controller for matching disturbance suppression and a second controller for compensating for non-matching disturbance as a control target, wherein the first controller outputs a first control law and the second controller outputs a second control law;

[0010] The first control law and the second control law are integrated to obtain a total control law, which is then used to coordinately control the suspension system of the maglev train by dynamically adjusting the electromagnet current.

[0011] In one embodiment, the control model of the maglev train suspension system is expressed as:

[0012]

[0013] in, is the input coefficient under the corresponding state, is the input coefficient variable. When the vacuum magnetic permeability, the number of turns of the suspension electromagnet coil, and the cross-sectional area of ​​the suspension electromagnet do not change and equal, , are two state variables, represents the air gap, represents the air gap change rate, yes The differential of yes The differential of is the acceleration due to gravity, is the input quantity, is a non-matching disturbance, To match the disturbance, is the vacuum magnetic permeability, N is the number of turns of the suspension electromagnet coil, and A is the cross-sectional area of ​​the suspension electromagnet.

[0014] In one embodiment, the cascade disturbance observer is configured as:

[0015]

[0016] in, , and are the state variable air gap of the system in the matching disturbance observer , air gap change rate And matching disturbance The observed value of and are the state variable air gap in the non-matched disturbance observer and non-matching disturbances Observed value of , , , and Is a normal number.

[0017] In one embodiment, the first controller is a sliding mode controller, and the output first control law u1 is expressed as:

[0018]

[0019] Among them, s is the sliding surface, which is expressed as:

[0020]

[0021] in, is the control parameter and satisfies , is the symbolic function, is a temporary integration variable, is the suspension force formula parameter, .

[0022] In one embodiment, the second controller is a proportional controller, and the output second control law is expressed as:

[0023]

[0024] in, is the second control law.

[0025] In one embodiment, the overall control law is set as a weighted sum of the first control law and the second control law.

[0026] In one embodiment, the overall control law is set as:

[0027]

[0028] in, is the first control law, is the second control law.

[0029] In one embodiment, The value of is obtained by integrating the acceleration or using a differentiator on the suspension gap.

[0030] According to a second aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, wherein when the computer program is executed by a processor, the steps of the composite control method of a maglev train suspension system based on a cascade disturbance observer are implemented.

[0031] Compared with the prior art, the advantage of the present invention is that the composite control method of the maglev train suspension system based on the cascade disturbance observer is provided, which introduces non-matching disturbance compensation in the control of the maglev train suspension system, so that the train can achieve rapid convergence under external complex disturbances, thereby effectively reducing the influence of external disturbances with complex action mechanisms such as aerodynamic excitation and line unevenness on the vertical stability of the maglev train.

[0032] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0034] Figure 1 is a flow chart of a composite control method of a maglev train suspension system based on a cascade disturbance observer according to an embodiment of the present invention;

[0035] Figure 2 is a schematic diagram of the overall process of a composite control method for a maglev train suspension system based on a cascade disturbance observer according to an embodiment of the present invention;

[0036] Figure 3 is a schematic diagram of a minimum suspension control unit of an electromagnetic suspension system according to an embodiment of the present invention;

[0037] Figure 4 is a relative reference model structure diagram of a single electromagnet suspension system according to an embodiment of the present invention;

[0038] Figure 5 It is a schematic diagram of simulation results comparing the suspension gap control effect of a control method according to an embodiment of the present invention and an existing composite control method based on a single disturbance observer. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0040] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0041] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0042] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0043] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0044] In general, the present invention designs a cascade observer based on the combination of a matched disturbance observer and a non-matched disturbance observer to observe the maglev train suspension system according to the Lyapunov stability theory. Then, a composite controller of the maglev train suspension system is designed, which includes a main controller for matching disturbance suppression and an auxiliary controller for compensating non-matched disturbance as the control focus.

[0045] In one embodiment, the composite control method of the maglev train suspension system based on the cascade disturbance observer generally includes: establishing a mathematical model of the suspension system based on the maglev train suspension system; introducing a cascade observer based on the mathematical model to estimate the unmeasurable state quantities and disturbances of the system; and designing a sliding mode controller and a proportional controller for control. The sliding mode control method is a nonlinear control method with significant flexibility. This is because the dynamic performance of the system is determined by the pre-designed sliding surface on which it operates. The design of the sliding surface directly affects the dynamic performance of the system. As long as the accessibility and stability of the sliding mode are guaranteed, the corresponding control can be achieved.

[0046] Specifically, combined Figure 1 and Figure 2 As shown, the composite control method of the maglev train suspension system based on the cascade disturbance observer includes the following steps.

[0047] Step S1, constructing a dynamic control model of the maglev train suspension system.

[0048] Specifically, the dynamic control model of the maglev train suspension system is constructed including:

[0049] Step S11: Perform force analysis on the suspension system of the maglev train to obtain a dynamic equation of the suspension system.

[0050] Figure 3 It is a schematic diagram of the minimum suspension control unit of the electromagnetic suspension system. Assuming that the magnetic permeability in the magnetic pole is infinite and the magnetic potential is evenly distributed on the air gap, and the winding leakage flux is ignored, the electromagnetic force at time t is (or abbreviated as ) is expressed as:

[0051] (1)

[0052] Where, t is time; is the suspended air gap; is the coil current; is the suspension force formula parameter, , is the vacuum permeability, is the number of turns of the suspension electromagnet coil, A is the cross-sectional area of ​​the suspension electromagnet, and m is the equivalent mass of the suspension system. Obviously, the functional relationship between the electromagnetic force and the air gap is a nonlinear relationship, which indicates that the suspension system of the maglev train is unstable and needs to be controlled.

[0053] The mechanical equilibrium equation of the suspension system in the vertical direction is:

[0054] (2)

[0055] in, is the equivalent mass of the suspension system; is the distance from the magnetic pole surface to the reference plane; is the acceleration due to gravity; is the non-matching disturbance size; is the suspension force formula parameter, , is the vacuum permeability, is the number of turns of the suspension electromagnet coil, is the cross-sectional area of ​​the suspension electromagnet; is the suspended air gap; is the coil current. Figure 4 The single electromagnet suspension system model considers the changes in the guide rail action surface and has the following relationship:

[0056] (3)

[0057] in, is the distance from the suspension track surface to the reference plane.

[0058] In summary, according to the dynamic equation and electromagnetic equation of the suspension system, the dynamic equation of the maglev train suspension system is obtained, which is expressed as:

[0059] (4)

[0060] Step S12: Perform force analysis on the suspension system of the maglev train to obtain the dynamic equation of the suspension system, and then construct a state space expression based on the dynamic equation of the suspension system to obtain the square of the current as the virtual control input. For example, the suspension system control model is expressed as:

[0061] (5)

[0062] in, , are the two state variables of the system, namely, the air gap and the air gap change rate, , Respectively represent the differentials of two state quantities of the system; is the acceleration due to gravity; , is the input coefficient under the corresponding state; is the input quantity; is a non-matching disturbance, To match the disturbance. is the input coefficient variable. When the vacuum magnetic permeability, the number of turns of the suspension electromagnet coil, and the cross-sectional area of ​​the suspension electromagnet do not change and equal.

[0063] Step S2: constructing a cascade disturbance observer to obtain unknown state quantities, wherein the cascade disturbance observer includes a matched disturbance observer and a non-matched disturbance observer.

[0064] In this step, a cascade disturbance observer is designed to obtain the unknown state quantity, i.e., the disturbance. For example, the cascade disturbance observer is set as:

[0065] (6)

[0066] in, are the state variable air gap of the system in the matching disturbance observer , air gap change rate and non-matching disturbances Observed value of are the state variable air gap in the non-matched disturbance observer And matching disturbance Observed value of , , >0, >0, The value of can be obtained by integrating the acceleration or using a differentiator on the suspension gap. It can be determined according to actual needs or simulation to make the magnetic levitation system stable.

[0067] Step S3, designing a composite controller for cooperative control, wherein the composite controller includes a main controller for matching disturbance suppression and an auxiliary controller focusing on compensating for non-matching disturbances.

[0068] Step S31: Consider the second-order uncertain nonlinear dynamic system of the suspension system:

[0069] (7)

[0070] in, , are two state variables of the system, namely, air gap and air gap change rate; is the acceleration due to gravity; , is the input coefficient under the corresponding state; is the scalar control input; is a non-matching disturbance, To match the disturbance.

[0071] Step S32: Design controller 1 as the main control law output, taking the sliding mode control law as an example:

[0072] (8)

[0073] in, is a temporary integral variable, indicating the change of the integral with the minimum time, is the control parameter and satisfies , is the symbolic function, s is the sliding surface, which can be expressed as:

[0074] (9)

[0075] Step S33: Design controller 2 as auxiliary control and output control law , taking the proportional controller as an example:

[0076] (10)

[0077] Step S34: Controller 1 and controller 2 are used for collaborative control. For example, controller 1 is a sliding mode controller, controller 2 is a proportional controller, and the output control laws of the two controllers are superimposed for control. The overall control law is set as:

[0078] (11)

[0079] It should be noted that the control laws output by the two controllers may also be weighted and summed to obtain a fused total control law for coordinated control, and the weighting coefficient may be determined according to actual needs or simulation.

[0080] To further verify the effect of the present invention, various types of software or self-developed software can be used for experimental verification. For example, the Simulink toolbox in Matlab is used to build a model and perform numerical simulation on the suspension system. The model consists of an observer and a suspension control. The initial position of the suspension electromagnet of the maglev train is set to deviate from the equilibrium point by about 10 mm, and the suspension gap stability value is 8 mm. The control system calculates the required control current through the observed air gap value and the change amount, and the electromagnetic force generated by the current affects the movement of the suspension system. The suspension system calculates the new body state as output based on parameters such as the input current and track displacement. Figure 5 The figure is a comparison diagram of the effects of the existing composite control method based on a single disturbance observer and the composite control method of the maglev train system based on a cascade disturbance observer of the present invention on the suspension gap control. Figure 5It can be seen that the present invention introduces non-matching disturbance compensation in the control of the maglev train suspension system, so that the train can achieve rapid convergence under external complex disturbances, thereby effectively reducing the impact of external disturbances with complex action mechanisms such as aerodynamic excitation and line unevenness on the vertical stability of the maglev train.

[0081] In summary, the present invention constructs a dynamic model of the maglev train suspension system; based on the dynamic model, a matching disturbance observer is introduced to estimate the unmeasurable state quantity of the system, and the controller 1 outputs a control law based on the estimated state quantity. Based on the dynamic model, a non-matching disturbance observer is introduced to obtain the estimated value of the non-matching disturbance differential component, and the output control law of controller 2 is designed based on the estimated value of the non-matching disturbance differential component. ;use and The total control law of addition Dynamically adjust the electromagnet current to ensure stable suspension of the maglev train.

[0082] The present invention may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

[0083] Computer readable storage medium can be a tangible device that can hold and store instructions used by an instruction execution device. Computer readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (non-exhaustive list) of computer readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, for example, a punch card or a convex structure in a groove on which instructions are stored, and any suitable combination thereof. The computer readable storage medium used here is not interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagated by a waveguide or other transmission medium (for example, a light pulse by an optical fiber cable), or an electrical signal transmitted by a wire.

[0084] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0085] The computer program instructions for performing the operation of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, Python, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect through the Internet). In some embodiments, by using the state information of the computer-readable program instructions to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit may execute the computer-readable program instructions, thereby implementing various aspects of the present invention.

[0086] Various aspects of the present invention are described herein with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to embodiments of the present invention. It should be understood that each box of the flowchart and / or block diagram and the combination of the boxes in the flowchart and / or block diagram can be implemented by computer-readable program instructions.

[0087] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device that implements the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions cause the computer, programmable data processing device, and / or other equipment to work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0088] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operating steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0089] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flow chart or block diagram can represent a part of a module, a program segment or an instruction, and a part of the module, a program segment or an instruction contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions. It is well known to those skilled in the art that it is equivalent to implement it by hardware, implement it by software, and implement it by combining software and hardware.

[0090] Embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the marketplace, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A composite control method for a maglev train suspension system based on a cascade disturbance observer, comprising the following steps: Construct a control model of the maglev train suspension system, which contains unknown state variables; Constructing a cascade disturbance observer for estimating the unknown state quantity, the cascade disturbance observer comprising a matched disturbance observer and a non-matched disturbance observer; Designing a composite controller, including a first controller for matching disturbance suppression and a second controller for compensating for non-matching disturbance as a control target, wherein the first controller outputs a first control law and the second controller outputs a second control law; The first control law and the second control law are integrated to obtain a total control law, and then the total control law is used to coordinately control the suspension system of the maglev train by dynamically adjusting the electromagnet current; The control model of the maglev train suspension system is expressed as: in, is the input coefficient under the corresponding state, is the input coefficient variable. When the vacuum magnetic permeability, the number of turns of the suspension electromagnet coil, and the cross-sectional area of ​​the suspension electromagnet do not change and equal, , are two state variables, represents the air gap, represents the air gap change rate, yes The differential of yes The differential of is the acceleration due to gravity, is the input quantity, is a non-matching disturbance, To match the disturbance, is the vacuum magnetic permeability, N is the number of turns of the suspension electromagnet coil, A is the cross-sectional area of ​​the suspension electromagnet, is the equivalent mass of the maglev train suspension system; Wherein, the cascade disturbance observer is set as: in, , and are the state variable air gap of the system in the matching disturbance observer , air gap change rate And matching disturbance The observed value of and are the state variable air gap in the non-matched disturbance observer and non-matching disturbances Observed value of , , , and is a positive constant; Wherein, the overall control law is set as: in, is the first control law, is the second control law.

2. The composite control method according to claim 1, characterized in that: The first controller is a sliding mode controller, and the output of the first control law It is expressed as: Among them, s is the sliding surface, which is expressed as: in, is the control parameter and satisfies , is the symbolic function, is a temporary integration variable, is the suspension force formula parameter, .

3. The composite control method according to claim 1, characterized in that: The second controller is a proportional controller, and the output second control law is expressed as: in, is the second control law.

4. The composite control method according to claim 1, characterized in that: The value of is obtained by integrating the acceleration or using a differentiator on the suspension gap.

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