Preset time tracking and synchronization control method, system, device and medium for four-motor drive system

Abstract

The present invention discloses a preset time tracking and synchronization control method, system, device and medium for a four-motor drive system. It belongs to the field of four-motor drive system control technology. The present invention introduces a command filter to obtain the differential of the virtual control law to avoid the problem of calculation explosion, and at the same time constructs a filter error compensation signal to clear the filter error to improve the control accuracy. In the backstepping method, the present invention designs a preset time controller so that the tracking error and the synchronization error converge within the preset time, improves the position tracking accuracy, and reduces the mechanical damage caused by inconsistent motor speeds. The present invention uses a fuzzy logic system to approximate nonlinear friction, so that the controller still has good tracking performance under the influence of friction nonlinearity.

Description

Technical Field

[0001] The present invention belongs to the technical field of four-motor drive system control, and in particular relates to a method, system, device and medium for preset time tracking and synchronous control of a four-motor drive system. Background Art

[0002] For large inertia servo systems, such as heavy-duty robotic arms, large machine tools, and radar antennas, using four motors instead of a single motor can effectively increase the drive torque and power while improving system reliability. Compared with a single motor, four motors must not only drive the load to track the position command signal, but also maintain speed synchronization. However, there may be differences in the characteristics between the motors, resulting in inconsistent motor speeds, which in turn causes mechanical wear and reduces service life. In addition, the four-motor drive system has a high order, complex structure, and friction nonlinearity, which makes it difficult to design a high-performance controller.

[0003] In order to obtain excellent control performance of the system, experts and scholars have proposed a variety of advanced control methods, such as sliding mode variable structure control, adaptive control, optimal control, backstepping control, etc. Backstepping is suitable for designing controllers for high-order nonlinear systems and is therefore widely used. However, in the traditional backstepping method, the repeated differentiation of the virtual control law brings about a computational explosion problem. Command filter control introduces a command filter to avoid the computational explosion problem. At the same time, the filter error compensation signal is constructed to eliminate the filter error and improve the control accuracy. Command filter control is combined with finite time control or fixed time control and applied to multi-motor drive systems, so that the system error can converge within a finite time or a fixed time. However, in the existing finite time command filter control for multi-motor drive systems, the error convergence time is affected by the initial state, while in the existing fixed time command filter control, the error convergence time is not affected by the initial state, but the convergence time cannot be pre-set, which brings inconvenience to the control parameter debugging. Therefore, how to achieve the convergence of the error of the multi-motor drive system within a preset time is a challenge. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a preset time tracking and synchronization control method, system, device and medium for a four-motor drive system, which can realize load position tracking of position command signals, motor speed synchronization, and tracking error and synchronization error converge within a preset time.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preset time tracking and synchronous control of a four-motor drive system comprises the following steps:

[0007] Step 1: Establish a dynamic model of the four-motor drive system and obtain a state space expression of the four-motor drive system;

[0008] Step 2: Based on the dynamic model of the four-motor drive system, a preset time command filter controller of the four-motor drive system is designed, wherein the preset time command filter controller includes a tracking controller and a synchronization controller, wherein the tracking controller generates a tracking control signal based on a position command signal, a load position tracking error and a preset error convergence time, and the synchronization controller generates a synchronization control signal based on a motor speed synchronization error and a preset error convergence time;

[0009] Step 3: The tracking control signal and the synchronization control signal are superimposed to generate a current command signal, which is used to control the load position response of the four-motor drive system to track the position command, and to control the speed synchronization of each motor, so as to achieve convergence of the load position tracking error and the motor speed synchronization error within a preset error convergence time.

[0010] To optimize the above technical solutions, the specific measures taken also include:

[0011] Furthermore, step 1 is specifically as follows:

[0012] The formula of the four-motor drive system dynamics model is as follows:

[0013]

[0014] Where j=1,2,3,4 is the motor number; θ l ,ω l are the position and velocity of the load, Represents θ l The first derivative of ; ω l The first derivative of mj ,ω mj are the position and speed of the jth motor respectively; J l , J mj are the inertia of the load and the inertia of the jth motor respectively; r is the transmission ratio; k s , k t , b mj are stiffness coefficient, torque coefficient and friction coefficient respectively; τ f is the friction torque; i j is the current of the jth motor;

[0015] Define the state variables and input variables as:

[0016]

[0017] Where x1 is the system state of the load position; x2 is the system state of the load speed; x 3j is the system state of the jth motor position; x 4j is the system state of the jth motor speed; uj is the system state of the jth motor current;

[0018] The state space expression of the four-motor drive system is expressed as:

[0019]

[0020] in, η1=rk s / J l , η 2j =k t / J mj , η 3j =k s / J mj , η 4j =b mj / J mj , ψ=-τ f / J l , x3 is the system state of the sum of the four motor positions; x4 is the system state of the sum of the four motor speeds, ψ is the unknown friction term of the system; η1, η 2j , η 3j and η 4j These are symbols set for simplicity of expression and have no actual meaning.

[0021] Further, in step 2, the tracking controller generates a tracking control signal based on the position command signal, the load position tracking error and the preset error convergence time, specifically:

[0022] Step 2.1, define the command filter, which is used to filter the virtual control signal. The command filter is as follows:

[0023]

[0024] Where i=1,2,3 represents the sequence number of the virtual control signal; α i is the input of the command filter, representing the ith virtual control signal, x i+1,c is the output of the command filter, indicating the ith virtual control signal after filtering; sig 1+κ (·)=|·| 1+κ sgn(·);sig 1-κ (·)=|·| 1-κ sgn(·); sgn(·) is the sign function; π is the circumference of a circle; 0<κ<1; T f >0; κ represents the command filter parameter, T f Indicates the command filter convergence time;

[0025] Step 2.2, define the load position tracking error:

[0026]

[0027] Among them, x r is the position command signal, indicating the desired load position; z1~z4 are the load position tracking errors in the backstepping design process; x 2,c is the first virtual control signal after filtering, x 3,c is the filtered second virtual control signal, x 4,c is the filtered third virtual control signal;

[0028] The load position tracking error is compensated by the filtered error compensation signal. The compensated load position tracking error is:

[0029] ζ i =z i -ξ i (6)

[0030] Where i = 1, 2, 3, 4; ζ i is the load position tracking error after compensation; i is the filtering error compensation signal;

[0031] Step 2.3, design the first virtual control signal α1 and the first filtering error compensation signal ξ1 as:

[0032]

[0033] Where a1 = 3πn ι / 2 / (2 1+ι / 2 ιT), b1=2π / (2 1-ι / 2 ιT), c1=2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d1=(2-ι)π / (2 1-ι / 2 ιT) are all control parameters; a1, b1, c1 and d1 are just for simplicity, ι is a power, 0<ι<1; T is half of the preset error convergence time; n is a constant;

[0034] Step 2.4: To approximate the unknown friction term ψ in formula (3), construct a fuzzy logic system W T S(x), where x = [x1, x2, x3, x4] T is the input vector of the fuzzy logic system, specifically the system state in the state space of the four-motor drive system, x1 is the system state of the load position; x2 is the system state of the load speed, x3 is the system state of the sum of the four-motor positions, and x4 is the system state of the sum of the four-motor speeds. W=[W1,…,W N ] T is the ideal weight vector; N is the number of fuzzy rules; S(x)=[S1(x),…,SN (x)] T is the basis function vector; S j (x) represents the basis function vector element, is a Gaussian function; v j represents the center value of the Gaussian function; w j represents the width of the Gaussian function; x i represents the i-th system state, i=1,2,3,4;

[0035] ||W|| 2 The estimated value is

[0036] Design the second virtual control signal α2, the second filtering error compensation signal ξ2, ||W|| 2 Estimated value of The adaptive laws are:

[0037]

[0038] Where a2 = 3πn ι / 2 / (2 1+ι / 2 ιT), b2=2π / (2 1-ι / 2 ιT), c2=2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d2=(2-ι)π / (2 1-ι / 2 ιT), All are control parameters; h>0 is the adaptive law parameter; S is the abbreviated form of the basis function vector S(x), n is an integer; z1 is the first load position tracking error;

[0039] Step 2.5: Design the third virtual control signal α3 and the third filtering error compensation signal ξ3 as:

[0040]

[0041] Where a3=3πn ι / 2 / (2 1+ι / 2 ιT), b3=2π / (2 1-ι / 2 ιT), c3=2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d3=(2-ι)π / (2 1-ι / 2 ιT) are control parameters; z2 is the second load position tracking error;

[0042] Step 2.6: Design the fourth filtering error compensation signal ξ4 as:

[0043]

[0044] Where c4 = 2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d4=(2-ι)π / (2 1-ι / 2 ιT) all represent control parameters;

[0045] Design tracking control signal u tj for:

[0046]

[0047] Where a4=2πn ι / 2 / (2 1+ι / 2 ιT), b4=2π / (2 1-ι / 2 ιT) represent control parameters.

[0048] Further, in step 2, the synchronous controller generates a synchronous control signal based on the motor speed synchronization error and the preset error convergence time, specifically:

[0049] Step 2.7, define the motor speed synchronization error:

[0050]

[0051] Define the first and third motors as the first group of motors, and the second and fourth motors as the second group of motors;

[0052] z v1 represents the speed synchronization error between the first motor and the third motor; v3 represents the speed synchronization error between the third motor and the first motor; z v2 represents the speed synchronization error between the second motor and the fourth motor; z v4 represents the speed synchronization error between the fourth motor and the second motor; z w Indicates the speed synchronization error between the first and second groups of motors;

[0053] Step 2.8: Design synchronization control signal u sj for:

[0054]

[0055] Among them, u vj is the synchronization control signal within the group; u wj is the inter-group synchronization control signal; a vj =πn ι / 2 / (2 1+ι / 2 ιT), b vj =π / (2 1-ι / 2 ιT), a w =πnι / 2 / (2 1+ι / 2 ιT), b w =π / (2 1-ι / 2 ιT) represent control parameters.

[0056] Further, in step 3, the current command signal is specifically:

[0057] u j =u tj +u sj (14)

[0058] In the formula, u j is the current command signal, u tj To track the control signal, u sj It is the synchronization control signal.

[0059] The present invention also proposes a preset time tracking and synchronization control system for a four-motor drive system, comprising:

[0060] A modeling module is used to establish a dynamic model of a four-motor drive system and obtain a state space expression of the four-motor drive system;

[0061] A controller design module, for designing a preset time command filter controller for a four-motor drive system based on a dynamic model of the four-motor drive system, wherein the preset time command filter controller includes a tracking controller and a synchronization controller, wherein the tracking controller generates a tracking control signal based on a position command signal, a load position tracking error, and a preset error convergence time, and the synchronization controller generates a synchronization control signal based on a motor speed synchronization error and a preset error convergence time;

[0062] The current command generation module is used to superimpose the tracking control signal and the synchronization control signal to generate a current command signal. The current command signal is used to control the load position response of the four-motor drive system to track the position command, and to control the speed synchronization of each motor to achieve the convergence of the load position tracking error and the motor speed synchronization error within a preset error convergence time.

[0063] The present invention also proposes an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the preset time tracking and synchronous control method of the four-motor drive system as described above is implemented.

[0064] The present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program enables a computer to execute the preset time tracking and synchronous control method of the four-motor drive system as described above.

[0065] The beneficial effects of the present invention are as follows: the present invention introduces a command filter to obtain the differential of the virtual control law, thereby avoiding the problem of computational explosion, and constructing a filter error compensation signal to eliminate the filter error and improve the control accuracy. In the backstepping method, the present invention designs a preset time command filter controller so that the tracking error and the synchronization error converge within a preset time, thereby improving the position tracking accuracy and reducing the mechanical damage caused by inconsistent motor speeds. The present invention uses a fuzzy logic system to approximate nonlinear friction, so that the controller still has good tracking performance under the influence of friction nonlinearity. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 1 is a flowchart of a preset time tracking and synchronization control method for a four-motor drive system in an embodiment of the present invention.

[0067] Figure 2 It is a tracking response curve diagram of load position instruction and position response after adopting the control method of the present invention.

[0068] Figure 3 It is a curve diagram of the load position tracking error after adopting the control method of the present invention.

[0069] Figure 4 It is a speed response curve diagram of each motor after adopting the control method of the present invention.

[0070] Figure 5 This is a synchronous error curve diagram after adopting the control method of the present invention. DETAILED DESCRIPTION

[0071] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0072] Embodiment 1

[0073] The present invention proposes a preset time tracking and synchronization control method for a four-motor drive system, such as Figure 1 As shown, the following steps are included:

[0074] Step 1: Establish a dynamic model of the four-motor drive system and obtain the state space expression of the four-motor drive system; Step 1 is specifically as follows:

[0075] The formula of the four-motor drive system dynamics model is as follows:

[0076]

[0077] Where j=1,2,3,4 is the motor number; θ l ,ω l are the position and velocity of the load, Represents θ l The first derivative of ; ω l The first derivative of mj ,ω mj are the position and speed of the jth motor respectively; J l , J mj are the inertia of the load and the inertia of the jth motor respectively; r is the transmission ratio; k s , k t , b mj are stiffness coefficient, torque coefficient and friction coefficient respectively; τ f is the friction torque; i j is the current of the jth motor;

[0078] Define the state variables and input variables as:

[0079]

[0080] Where x1 is the system state of the load position; x2 is the system state of the load speed; x 3j is the system state of the jth motor position; x 4j is the system state of the jth motor speed; u j is the system state of the jth motor current;

[0081] The state space expression of the four-motor drive system is expressed as:

[0082]

[0083] in, η1=rk s / J l , η 2j =k t / J mj , η 3j =k s / J mj , η 4j =b mj / J mj , ψ=-τ f / J l , x3 is the system state of the sum of the four motor positions; x4 is the system state of the sum of the four motor speeds, ψ is the unknown friction term of the system; η1, η 2j , η 3j and η 4j These are symbols set for simplicity of expression and have no actual meaning.

[0084] Step 2: Based on the dynamic model of the four-motor drive system, a preset time command filter controller for the four-motor drive system is designed. The preset time command filter controller includes a tracking controller and a synchronization controller. The tracking controller generates a tracking control signal based on the position command signal, the load position tracking error and the preset error convergence time. The synchronization controller generates a synchronization control signal based on the motor speed synchronization error and the preset error convergence time. In step 2, the tracking controller generates a tracking control signal based on the position command signal, the load position tracking error and the preset error convergence time. Specifically:

[0085] Step 2.1, define the command filter, which is used to filter the virtual control signal. The command filter is as follows:

[0086]

[0087] Where i=1,2,3 represents the sequence number of the virtual control signal; α i is the input of the command filter, representing the ith virtual control signal, x i+1,c is the output of the command filter, indicating the ith virtual control signal after filtering; sig 1+κ (·)=|·| 1+κ sgn(·);sig 1-κ (·)=|·| 1-κ sgn(·); sgn(·) is the sign function; π is the circumference of a circle; 0<κ<1; T f >0; κ represents the command filter parameter, T f Indicates the command filter convergence time;

[0088] Step 2.2, define the load position tracking error:

[0089]

[0090] Among them, x r is the position command signal, indicating the desired load position; z1~z4 are the load position tracking errors in the backstepping design process; x 2,c is the first virtual control signal after filtering, x 3,c is the second virtual control signal after filtering, x 4,c is the filtered third virtual control signal;

[0091] The load position tracking error is compensated by using the filtered error compensation signal. The compensated load position tracking error is:

[0092] ζ i =z i -ξ i (6)

[0093] Where i = 1, 2, 3, 4; ζ i is the load position tracking error after compensation; i is the filtering error compensation signal;

[0094] Step 2.3, design the first virtual control signal α1 and the first filtering error compensation signal ξ1 as:

[0095]

[0096] Where a1 = 3πn ι / 2 / (2 1+ι / 2 ιT), b1=2π / (2 1-ι / 2 ιT), c1=2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d1=(2-ι)π / (2 1-ι / 2 ιT) are all control parameters; a1, b1, c1 and d1 are just for simplicity, ι is a power, 0<ι<1; T is half of the preset error convergence time; n is a constant;

[0097] Step 2.4: To approximate the unknown friction term ψ in formula (3), construct a fuzzy logic system W T S(x), where x = [x1, x2, x3, x4] T is the input vector of the fuzzy logic system, specifically the system state in the state space of the four-motor drive system, x1 is the system state of the load position; x2 is the system state of the load speed, x3 is the system state of the sum of the four-motor positions, and x4 is the system state of the sum of the four-motor speeds. W=[W1,…,W N ] T is the ideal weight vector; N is the number of fuzzy rules; S(x)=[S1(x),…,S N (x)] T is the basis function vector; S j (x) represents the basis function vector element, is a Gaussian function; v j represents the center value of the Gaussian function; w j represents the width of the Gaussian function; x i represents the i-th system state, i=1,2,3,4;

[0098] ||W|| 2 The estimated value is

[0099] Design the second virtual control signal α2, the second filtering error compensation signal ξ2, ||W|| 2 Estimated value of The adaptive laws are:

[0100]

[0101] Where a2 = 3πn ι / 2 / (2 1+ι / 2 ιT), b2=2π / (2 1-ι / 2 ιT), c2=2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d2=(2-ι)π / (2 1-ι / 2 ιT), All are control parameters; h>0 is the adaptive law parameter; S is the abbreviated form of the basis function vector S(x), n is an integer; z1 is the first load position tracking error;

[0102] Step 2.5: Design the third virtual control signal α3 and the third filtering error compensation signal ξ3 as:

[0103]

[0104] Where a3=3πn ι / 2 / (2 1+ι / 2 ιT), b3=2π / (2 1-ι / 2 ιT), c3=2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d3=(2-ι)π / (2 1-ι / 2 ιT) are control parameters; z2 is the second load position tracking error;

[0105] Step 2.6: Design the fourth filtering error compensation signal ξ4 as:

[0106]

[0107] Where c4 = 2(2+ι)πn ι / 2 / (2 1+ι / 2 ιT), d4=(2-ι)π / (2 1-ι / 2 ιT) all represent control parameters;

[0108] Design tracking control signal u tj for:

[0109]

[0110] Where a4=2πn ι / 2 / (2 1+ι / 2 ιT), b4=2π / (2 1-ι / 2 ιT) represent control parameters.

[0111] In step 2, the synchronous controller generates a synchronous control signal based on the motor speed synchronization error and the preset error convergence time, specifically:

[0112] Step 2.7, define the motor speed synchronization error:

[0113]

[0114] Define the first and third motors as the first group of motors, and the second and fourth motors as the second group of motors;

[0115] z v1 represents the speed synchronization error between the first motor and the third motor; v3 represents the speed synchronization error between the third motor and the first motor; z v2 represents the speed synchronization error between the second motor and the fourth motor; z v4 represents the speed synchronization error between the fourth motor and the second motor; z w Indicates the speed synchronization error between the first and second groups of motors;

[0116] Step 2.8: Design synchronization control signal u sj for:

[0117]

[0118] Among them, u vj is the synchronization control signal within the group; u wj is the inter-group synchronization control signal; a vj =πn ι / 2 / (2 1+ι / 2 ιT), b vj =π / (2 1-ι / 2 ιT), a w =πn ι / 2 / (2 1+ι / 2 ιT), b w =π / (2 1-ι / 2 ιT) represent control parameters.

[0119] Step 3: The tracking control signal and the synchronization control signal are superimposed to generate a current command signal, which is used to control the load position response of the four-motor drive system to track the position command, and to control the speed synchronization of each motor, so as to achieve the convergence of the load position tracking error and the motor speed synchronization error within the preset error convergence time. In step 3, the current command signal is specifically:

[0120] u j =u tj +u sj (14)

[0121] In the formula, u jis the current command signal, u tj To track the control signal, u sj It is the synchronization control signal.

[0122] In order to prove the effect of the preset time command filter controller designed by the present invention, the Lyapunov function V is constructed as:

[0123]

[0124] Then the derivative of V satisfies:

[0125]

[0126] Here, Δ is a positive number.

[0127] It can be seen from formula (16) that after applying the designed controller, the closed-loop system satisfies the practical preset time stability in the sense of Lyapunov, that is, the tracking error and the synchronization error converge to an error band within the preset time 2T.

[0128] Embodiment 2

[0129] The present invention proposes a preset time tracking and synchronization control system for a four-motor drive system corresponding to the method of the first embodiment, comprising:

[0130] A modeling module is used to establish a dynamic model of a four-motor drive system and obtain a state space expression of the four-motor drive system;

[0131] A controller design module, for designing a preset time command filter controller for a four-motor drive system based on a dynamic model of the four-motor drive system, wherein the preset time command filter controller includes a tracking controller and a synchronization controller, wherein the tracking controller generates a tracking control signal based on a position command signal, a load position tracking error, and a preset error convergence time, and the synchronization controller generates a synchronization control signal based on a motor speed synchronization error and a preset error convergence time;

[0132] The current command generation module is used to superimpose the tracking control signal and the synchronization control signal to generate a current command signal. The current command signal is used to control the load position response of the four-motor drive system to track the position command, and to control the speed synchronization of each motor to achieve the convergence of the load position tracking error and the motor speed synchronization error within a preset error convergence time.

[0133] The implementation methods of each module and module function in the system are completely consistent with the steps of the method in Example 1, so they will not be repeated here.

[0134] Embodiment 3

[0135] The present invention proposes an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the preset time tracking and synchronous control method of the four-motor drive system as described in Example 1 is implemented.

[0136] Embodiment 4

[0137] The present invention provides a computer-readable storage medium storing a computer program, wherein the computer program enables a computer to execute the preset time tracking and synchronous control method of a four-motor drive system as described in the first embodiment.

[0138] The following experiment is conducted on a four-motor drive system experimental platform to test the preset time tracking and synchronization control method (denoted as PTCFC) of the four-motor drive system proposed by the present invention to verify the feasibility of the control method proposed by the present invention:

[0139] Experimental platform system parameters: J mj =0.000323kg·m 2 , b mj =1.43×10 -4 N·m·s / rad,k t =1.11N·m / A, J l =68kg·m 2 , r=170.

[0140] Control parameters: ι = 4 / 11, T = 0.25, v j =j-6, N = 11, h = 20, κ=0.4,T f =0.005.

[0141] Perform a sinusoidal command experiment, the load position command signal is x r =π / 3·sin(t)rad, the initial position is π / 9rad.

[0142] Figure 2 and Figure 3 shows the system tracking performance, Figure 2 The medium position response quickly tracks the position command during the dynamic process. Figure 3 The tracking error converges quickly and the steady-state tracking error is very small.

[0143] Figure 4 and Figure 5 Shows the system synchronization performance, Figure 4 The speed of each motor is kept consistent. Figure 5 The synchronization error of group one, group two and group-to-group synchronization errors all converge quickly, and the steady-state synchronization error is very small.

[0144] Experimental results show that the preset time tracking and synchronization control method for the four-motor drive system proposed in the present invention has good tracking performance and synchronization performance, and the error can converge to a small error band within the preset time.

[0145] In the embodiments disclosed in the present application, the computer storage medium can be a tangible medium that can contain or store a program for use by or in conjunction with an instruction execution system, device or equipment. The computer storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the above. More specific examples of computer storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above.

[0146] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0147] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A preset time tracking and synchronization control method for a four-motor drive system, characterized in that: The following steps are involved: Step 1: Establish a dynamic model of the four-motor drive system and obtain a state space expression of the four-motor drive system; Step 2: Based on the dynamic model of the four-motor drive system, a preset time command filter controller of the four-motor drive system is designed, wherein the preset time command filter controller includes a tracking controller and a synchronization controller, wherein the tracking controller generates a tracking control signal based on a position command signal, a load position tracking error and a preset error convergence time, and the synchronization controller generates a synchronization control signal based on a motor speed synchronization error and a preset error convergence time; Step 3: The tracking control signal and the synchronization control signal are superimposed to generate a current command signal, which is used to control the load position response of the four-motor drive system to track the position command, and to control the speed synchronization of each motor, so as to achieve convergence of the load position tracking error and the motor speed synchronization error within a preset error convergence time.

2. The preset time tracking and synchronous control method of the four-motor drive system according to claim 1, characterized in that: Step 1 is as follows: The formula of the four-motor drive system dynamics model is as follows: Where j=1,2,3,4 is the motor number; θ l ,ω l are the position and velocity of the load, Represents θ l The first derivative of ; ω l The first derivative of mj ,ω mj are the position and speed of the jth motor respectively; J l , J mj are the inertia of the load and the inertia of the jth motor respectively; r is the transmission ratio; k s , k t , b mj are stiffness coefficient, torque coefficient and friction coefficient respectively; t f is the friction torque; i j is the current of the jth motor; Define the state variables and input variables as: Where x1 is the system state of the load position; x2 is the system state of the load speed; x 3j is the system state of the jth motor position; x 4j is the system state of the jth motor speed; u j is the system state of the j-th motor current; The state space expression of the four-motor drive system is expressed as: in, h1=rk s / J l ,h 2j =k t / J mj ,h 3j =k s / J mj ,h 4j =b mj / J mj , y=-t f / J l , x3 is the system state of the sum of the four motor positions; x4 is the system state of the sum of the four motor speeds, y is the unknown friction term of the system; h1, h 2j 、h 3j and h 4j These are symbols set for simplicity of expression and have no actual meaning.

3. The preset time tracking and synchronous control method of the four-motor drive system according to claim 2, characterized in that: In step 2, the tracking controller generates a tracking control signal based on the position command signal, the load position tracking error and the preset error convergence time, specifically: Step 2.1, define the command filter, which is used to filter the virtual control signal. The command filter is as follows: Where i=1, 2, 3 represents the sequence number of the virtual control signal; a i is the input of the command filter, representing the ith virtual control signal, x i+1,c is the output of the command filter, indicating the ith virtual control signal after filtering; sig 1+k (·)=|· 1+k sgn(·);sig 1-k (·)=|· 1-k sgn(·); sgn(·) is the sign function; p is pi; 0 <k<1;T f >0; k represents the command filter parameter, T f Indicates the command filter convergence time; Step 2.2, define the load position tracking error: Among them, x r is the position command signal, indicating the desired load position; z1~z4 are the load position tracking errors in the backstepping design process; x 2,c is the first virtual control signal after filtering, x 3,c is the filtered second virtual control signal, x 4,c is the filtered third virtual control signal; The load position tracking error is compensated by the filtered error compensation signal. The compensated load position tracking error is: z i =z i -x i (6) Where i = 1, 2, 3, 4; z i is the load position tracking error after compensation; x i is the filtering error compensation signal; Step 2.3: Design the first virtual control signal a1 and the first filtering error compensation signal x1 as: where a1 = 3pn i / 2 / (2 1+i / 2 iT), b1 = 2p / (2 1-i / 2 iT), c1 = 2(2 + i)pn i / 2 / (2 1+i / 2 iT), d1 = (2 - i)p / (2 1-i / 2 iT) are all control parameters; a1, b1, c1, and d1 are only for the sake of concise expression, i is the power, 0 < i < 1; T is half of the preset error convergence time; n is a constant; Step 2.4: To approximate the unknown friction term y in formula (3), construct a fuzzy logic system W T S(x), where x = [x1, x2, x3, x4] T is the input vector of the fuzzy logic system, specifically the system state of the state space of the four-motor drive system, x1 is the system state of the load position; x2 is the system state of the load speed, x3 is the system state of the sum of the four-motor positions, and x4 is the system state of the sum of the four-motor speeds. W=[W1,L,W N ] T is the ideal weight vector; N is the number of fuzzy rules; S(x)=[S1(x),L,S N (x)] T is the basis function vector; S j (x) represents the basis function vector element, is a Gaussian function; v j represents the center value of the Gaussian function; w j represents the width of the Gaussian function; x i represents the i-th system state, i=1,2,3,4; ||W|| 2 The estimated value is Design the second virtual control signal a2, the second filtering error compensation signal x2, ||W|| 2 Estimated value of The adaptive laws are: Where a2 = 3pn i / 2 / (2 1+i / 2 iT), b2 = 2p / (2 1-i / 2 iT)、c2=2(2+i)pn i / 2 / (2 1+i / 2 iT), d2 = (2-i)p / (2 1-i / 2 iT)、 All are control parameters; h>0 is the adaptive law parameter; S is the abbreviated form of the basis function vector S(x), n is an integer; z1 is the first load position tracking error; Step 2.5: Design the third virtual control signal a3 and the third filtering error compensation signal x3 as: Where a3 = 3pn i / 2 / (2 1+i / 2 iT), b3 = 2p / (2 1-i / 2 iT), c3=2(2+i)pn i / 2 / (2 1+i / 2 iT), d3 = (2-i)p / (2 1-i / 2 iT) are control parameters; z2 is the second load position tracking error; Step 2.6, design the fourth filtering error compensation signal x4 as: In the formula, c4=2(2+i)pn i / 2 / (2 1+i / 2 iT), d4 = (2-i)p / (2 1-i / 2 iT) all represent control parameters; Design tracking control signal u tj for: Where a4 = 2pn i / 2 / (2 1+i / 2 iT), b4=2p / (2 1-i / 2 iT) all represent control parameters.

4. The preset time tracking and synchronous control method of the four-motor drive system according to claim 3, characterized in that: In step 2, the synchronous controller generates a synchronous control signal based on the motor speed synchronization error and the preset error convergence time, specifically: Step 2.7, define the motor speed synchronization error: Define the first and third motors as the first group of motors, and the second and fourth motors as the second group of motors; z v1 represents the speed synchronization error between the first motor and the third motor; v3 represents the speed synchronization error between the third motor and the first motor; z v2 represents the speed synchronization error between the second motor and the fourth motor; z v4 represents the speed synchronization error between the fourth motor and the second motor; z w Indicates the speed synchronization error between the first and second groups of motors; Step 2.8: Design synchronization control signal u sj for: Among them, u vj u is the synchronization control signal within the group; wj is the inter-group synchronization control signal; a vj =pn i / 2 / (2 1+i / 2 iT), b vj =p / (2 1-i / 2 iT)、a w =pn i / 2 / (2 1+i / 2 iT), b w =p / (2 1-i / 2 iT) all represent control parameters.

5. The preset time tracking and synchronous control method of the four-motor drive system according to claim 4, characterized in that: In step 3, the current command signal is specifically: in j =in tj +in sj (14) In the formula, u j is the current command signal, u tj To track the control signal, u sj It is the synchronization control signal.

6. A preset time tracking and synchronization control system for a four-motor drive system, characterized in that: include: A modeling module is used to establish a dynamic model of a four-motor drive system and obtain a state space expression of the four-motor drive system; A controller design module, for designing a preset time command filter controller for a four-motor drive system based on a dynamic model of the four-motor drive system, wherein the preset time command filter controller includes a tracking controller and a synchronization controller, wherein the tracking controller generates a tracking control signal based on a position command signal, a load position tracking error, and a preset error convergence time, and the synchronization controller generates a synchronization control signal based on a motor speed synchronization error and a preset error convergence time; The current command generation module is used to superimpose the tracking control signal and the synchronization control signal to generate a current command signal. The current command signal is used to control the load position response of the four-motor drive system to track the position command, and to control the speed synchronization of each motor to achieve the convergence of the load position tracking error and the motor speed synchronization error within a preset error convergence time.

7. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the preset time tracking and synchronous control method of the four-motor drive system as described in any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium storing a computer program, characterized in that: The computer program enables the computer to execute the preset time tracking and synchronous control method of the four-motor drive system as described in any one of claims 1-5.

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