A ball screw permanent magnet synchronous motor speed and current control system and method based on anti-disturbance control

Abstract

The present invention relates to a ball screw permanent magnet synchronous motor speed current control system and method based on self-disturbance rejection control, belonging to the field of numerical control machine tools. The method comprises: S1: constructing a mathematical model of a permanent magnet synchronous motor and a ball screw pair, and then constructing a permanent magnet synchronous motor servo control system model according to the coupling relationship between the two; S2: constructing a self-disturbance rejection control model of a permanent magnet synchronous motor servo control system, including: the excitation and torque current loops are designed using a first-order ADRC algorithm; the speed loop is designed using a second-order ADRC algorithm. The present invention can effectively improve the speed current dynamic characteristics and robustness of the permanent magnet synchronous motor servo control system.

Description

Technical Field

[0001] The invention belongs to the field of numerically controlled machine tools, and relates to a speed and current control system and method of a ball screw permanent magnet synchronous motor based on self-disturbance rejection control. Background Art

[0002] In the field of CNC machine tools, the permanent magnet synchronous motor servo control system based on ball screw is an important component of CNC machine tools. The control performance of the permanent magnet synchronous motor servo control system has a great influence on the processing quality of CNC machine tools. At present, most servo control systems of CNC machine tools still use traditional PID control to control permanent magnet synchronous motors. However, in practical applications, there is a certain degree of uncertainty and nonlinear load changes in the permanent magnet synchronous motor servo control system, which makes it impossible to establish an accurate mathematical model for the servo control system, and it is difficult to achieve precise control with traditional PID control methods. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a ball screw permanent magnet synchronous motor speed and current control system and method based on self-anti-disturbance control to address the problem that traditional PID control methods are difficult to achieve precise control of permanent magnet synchronous motors when system parameters are subject to uncertainty and nonlinear changes. The speed and current dynamic characteristics and robustness of the permanent magnet synchronous motor servo control system can be effectively improved.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] Solution 1: A method for controlling the speed and current of a ball screw permanent magnet synchronous motor based on anti-disturbance control, comprising the following steps:

[0006] S1: Construct the mathematical model of the permanent magnet synchronous motor and the ball screw pair, and then construct the permanent magnet synchronous motor servo control system model based on the coupling relationship between the two;

[0007] S2: Construct an anti-disturbance control model for the permanent magnet synchronous motor servo control system, including: the excitation and torque current loops are designed using the first-order ADRC algorithm; the speed loop is designed using the second-order ADRC algorithm.

[0008] Further, in step S1, a mathematical model of a permanent magnet synchronous motor is constructed, specifically including: the voltage equation of each phase winding of the permanent magnet synchronous motor is:

[0009]

[0010] Among them, u A 、u B and u C is the stator winding phase voltage, i A 、i B and i Cis the phase current of the stator winding, e A 、e B and e C is the stator winding back electromotive force, R is the winding resistance, L and M are the stator winding self-inductance and the mutual inductance between windings, respectively, and L and M are both constants;

[0011] Without considering mechanical loss, the electromagnetic torque of the permanent magnet synchronous motor is:

[0012]

[0013] Among them, T e is the electromagnetic torque, ω is the mechanical angular velocity of the permanent magnet synchronous motor;

[0014] The mechanical motion equation of a permanent magnet synchronous motor is:

[0015]

[0016] Among them, T L is the load torque, B v is the damping coefficient, and J is the moment of inertia of the rotor.

[0017] Further, in step S1, a mathematical model of the ball screw pair is constructed, specifically including: a rigid body dynamics model of the ball screw pair mechanical transmission device is:

[0018]

[0019] Among them, J g is the total equivalent moment of inertia of the ball screw, which is composed of the moment of inertia of the mechanical structure such as the output shaft of the permanent magnet synchronous motor, coupling, ball screw, nut and workbench; T m Represents the output torque of the motor, T d Indicates the disturbance torque equivalent to the ball screw of the mechanical transmission part (such as friction, ripple resistance, etc.), B g is the viscous damping coefficient, θ(t) is the rotation angle of the permanent magnet synchronous motor, represents the derivative of θ(t);

[0020] The transfer function G(s) of the mechanical transmission system is:

[0021]

[0022] Among them, K s is the rotational stiffness, r g is the actual displacement of the worktable when the permanent magnet synchronous motor rotates one circle, S is the complex variable in the transfer function, which is called the complex frequency;

[0023] From the transfer function G(s), it can be concluded that the ball screw mechanical transmission system is a typical second-order oscillation link, and the state space expression is:

[0024]

[0025] Where x is the displacement of the worktable, are the second-order derivative and first-order derivative of x respectively, y is the system output, i.e., the actual displacement of the workbench, B e is the external viscous damping coefficient of the ball screw system, J e is the system control matrix ball screw moment of inertia, and u is the system control variable group.

[0026] Further, in step S1, a permanent magnet synchronous motor servo control system model is constructed, specifically including: using vector control to control the permanent magnet synchronous motor servo control system, converting the permanent magnet synchronous motor mathematical model from the abc coordinate system to the dq coordinate system, and the mathematical model of the permanent magnet synchronous motor in the dq coordinate system is:

[0027]

[0028] Among them, Ld and L q are the dq axis inductance, i d and i q are dq axis current, u d and u q are dq axis voltage, R s is the stator phase resistance, ω r is the rotor angular velocity, L md is the d-axis excitation inductance, i f is the d-axis excitation current, p n is the pole pair number, T e and T L are electromagnetic torque and load torque respectively, B is the viscous damping coefficient, and J is the moment of inertia of the rotor;

[0029] Combining equation (7) with the mathematical model of the permanent magnet synchronous motor and the ball screw pair, the transfer function of the permanent magnet synchronous motor servo control system is calculated, and the coupling relationship between the permanent magnet synchronous motor and the ball screw pair is obtained through the transfer function relationship.

[0030] Further, in step S2, the excitation and torque current loops are designed using a first-order ADRC algorithm, specifically including: The calculation formula of the torque current is obtained from equation (7):

[0031]

[0032] Let b0 = 1 / L q is the controller gain, is the total disturbance of the controller;

[0033] The tracking differentiator TD satisfies:

[0034]

[0035] The extended state observer LESO satisfies:

[0036]

[0037] The nonlinear state error feedback rate NLSEF satisfies:

[0038]

[0039] In the design of the current loop, e0, e1, and e2 are error signals; v0 is the given current signal, and v1 is the softened tracking given current signal; z1 is the observed input signal, and z2 is the observed total disturbance signal; y is the actual output value of the test bench control system; α0, α1, and α2 are tracking factors; δ0, δ1, and δ2 are filtering factors; β1 and β2 are correction factors, and k is the proportional coefficient; b0 is the controller gain factor; u is the system control quantity matrix, and u0 is the system initial control quantity matrix.

[0040] The fall function is defined as follows:

[0041]

[0042] Where 0<α<1 and δ>0 are constants. This function is not only piecewise smooth but also has the characteristics of small error and large gain and large error and small gain. NLSEF is a nonlinear controller, and its output control signal and the disturbance state observation of ESO together constitute the input signal of the controlled object.

[0043] The motor dq axis inductance is the same. When the load torque is zero, the system speed loop open-loop transfer function is:

[0044]

[0045] Where: K n is the controller proportional coefficient, T pwm is the controller integral time constant, τ n is the influencing factor of the speed loop system, and s is the complex variable in the transfer function, called the complex frequency.

[0046] Further, in step S2, the speed loop is designed by using the second-order ADRC algorithm, which specifically includes: the following expression is obtained from equation (4), equation (7) and equation (13):

[0047]

[0048] Among them, ψ fis the rotor flux; let b0=3p n 2 ψ f / 2(J+p n J g ) is the controller gain. Since the dq axis inductance of the permanent magnet synchronous motor is the same, f = -[p n T d +(B+p n B g )ω r ] / (J+p n J g ) is the total disturbance of the controller;

[0049] The TD part meets the following requirements:

[0050]

[0051] LESO partially meets:

[0052]

[0053] NLSEF partially meets:

[0054]

[0055] In the speed loop design, v1 is the softened tracking signal of v0, v2 is the differential signal of v1, r0 is the speed factor, h0 is the filter factor, fhan(·) is the fastest comprehensive function, which can prevent the system from overshooting; z1 is the observed input signal, z2 is the observed differential signal, z3 is the observed disturbance signal, β 01 , β 02 , β 03 , δ are adjustable parameters; e1 and e2 are error signal and differential error signal respectively, β1, β2, α1, α2, δ are adjustable parameters; δ1 and δ2 are adjustable constants; ε1 is the error signal; b0 is the controller gain factor, and u is the system control variable group.

[0056] Solution 2: A ball screw permanent magnet synchronous motor speed and current control system based on self-disturbance rejection control, comprising a transmission system, a control circuit and a motor drive circuit; the transmission system comprises a permanent magnet synchronous motor and a ball screw pair; the control circuit comprises a microprocessor, a signal isolation circuit and a detection circuit;

[0057] The microprocessor is used to execute the control method, specifically including: executing the control program, sending control instructions to the motor drive circuit, feedback signal detection, realizing resource scheduling between multiple tasks, communicating with the host computer, and fault diagnosis; the signal isolation circuit is used to separate the control signal sent by the microprocessor from the actual drive signal, reduce the coupling relationship between the microprocessor and the motor drive circuit, and isolate the Hall sensor signal from the microprocessor, thereby protecting the microprocessor control circuit.

[0058] Furthermore, the motor drive circuit adopts a three-phase drive circuit, which regularly turns on and off the DC direct current through the MOSFET, and finally converts it into Phase_A / B / C three-phase electricity to drive the motor to operate normally.

[0059] The beneficial effects of the present invention are as follows: in view of the problem that the traditional PID control method is difficult to achieve precise control of the permanent magnet synchronous motor when the system parameters are subject to uncertainty and nonlinear changes, the present invention uses the permanent magnet synchronous motor and the ball screw as an experimental platform to design a speed and current ADRC method, which can effectively improve the dynamic characteristics and robustness of the permanent magnet synchronous motor servo control system.

[0060] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0062] Figure 1 This is the structural block diagram of the permanent magnet synchronous motor servo control system;

[0063] Figure 2 This is the working principle diagram of the permanent magnet synchronous motor servo control system;

[0064] Figure 3 This is the vector control block diagram of the permanent magnet synchronous motor;

[0065] Figure 4 It is the structural block diagram of the second-order ADRC;

[0066] Figure 5 This is the hardware structure diagram of the control system;

[0067] Figure 6 Design framework diagrams for software;

[0068] Figure 7 It is a program flow chart between multiple tasks;

[0069] Figure 8 This is the task flow chart for calculating the motor speed;

[0070] Fig. 9 It is the control flow chart of speed ADRC;

[0071] Fig.10 It is the control flow chart of current ADRC;

[0072] Fig.11 Execute the flow chart for the fault detection task. DETAILED DESCRIPTION

[0073] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0074] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0075] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0076] See also Figures 1 to 11 This embodiment provides a method for controlling the speed and current of a ball screw permanent magnet synchronous motor based on anti-disturbance control. It includes the following parts:

[0077] 1. Analyze the mathematical model of permanent magnet synchronous motor and ball screw, and clarify the model structure based on the coupling relationship between the two.

[0078] 1) Mathematical model of permanent magnet synchronous motor

[0079] In order to simplify the mathematical model of permanent magnet synchronous motor, it is assumed under ideal conditions:

[0080] ① Ignore the impact of core saturation, eddy current and hysteresis loss on the motor;

[0081] ② Ignore the motor processing error and assume that the armature winding is evenly distributed;

[0082] ③The switching device of the driver has ideal switching characteristics.

[0083] ④ The three-phase windings of the permanent magnet synchronous motor are symmetrical and constant.

[0084] Based on the above assumptions, the mathematical model of the A-phase winding of the permanent magnet synchronous motor can be expressed as:

[0085] u A =R A i A +e ψA (1)

[0086] Among them, u A is the phase voltage of phase A winding, P A is the winding resistance of phase A, i A is the phase current of phase A, e ψA It is the induced potential generated by the winding inductance of phase A.

[0087] The induced potential generated by the winding inductance is equal to the derivative of the magnetic flux. Therefore, the induced potential is:

[0088]

[0089] The flux equation of phase A winding can be expressed as:

[0090] ψ A =L A i A +M AB i B +M AC i C +ψ pm (θ) (3)

[0091] Among them, L A is the self-inductance of phase A winding, M AB With M AC They are the mutual inductances between phase A and phase B, and between phase A and phase C. ψ pm (θ) is the permanent magnet flux of phase A winding.

[0092] Combining equations (1), (2) and (3), the voltage equation of phase A winding can be obtained as follows:

[0093]

[0094] The three-phase windings are star-connected and symmetrical to each other, so equation (4) can be simplified to:

[0095]

[0096] According to formula (5), the voltage equation of each phase winding can be obtained as follows:

[0097]

[0098] Among them, u A 、u B and u C is the stator winding phase voltage, i A 、i B and i C is the phase current of the stator winding, e A 、e B and e C is the back electromotive force of the stator winding, L and M are the self-inductance of the stator winding and the mutual inductance between windings respectively, and both L and M are constants.

[0099] Without considering mechanical loss, the electromagnetic torque of the permanent magnet synchronous motor is:

[0100]

[0101] Here, T e is the electromagnetic torque, and ω is the mechanical angular velocity of the permanent magnet synchronous motor.

[0102] The mechanical motion equation of a permanent magnet synchronous motor is:

[0103]

[0104] Among them, T L is the load torque, B v is the damping coefficient, and J is the moment of inertia of the rotor.

[0105] The mathematical model of permanent magnet synchronous motor is composed of formulas (6), (7) and (8).

[0106] 2) Ball screw pair mathematical model

[0107] The dynamic model of the ball screw can be divided into a rigid body model and a flexible body model. In practical applications, the elastic deformation of the servo control system is generally ignored, the mechanical structure is simplified into a rigid body model, and the ball screw pair and the motor drive shaft are analyzed as a whole. However, the ball screw pair has more or less elastic deformation, and when the workbench is nonlinearly disturbed, it may cause vibration of the servo control system.

[0108] Assuming that the displacement of the worktable is proportional to the motor speed, the following equation holds true:

[0109]

[0110] Where x(t) is the displacement of the worktable, r g is the actual displacement of the worktable when the permanent magnet synchronous motor rotates one circle, θ(t) is the rotation angle of the permanent magnet synchronous motor, and h sp is the screw lead.

[0111] The rigid body dynamics model of the ball screw pair mechanical transmission device is as follows:

[0112]

[0113] Among them, J g T is the total equivalent moment of inertia of the ball screw, which is composed of the moment of inertia of the permanent magnet synchronous motor output shaft, coupling, ball screw, nut and workbench. m Represents the output torque of the motor, T d Indicates the disturbance torque equivalent to the ball screw of the mechanical transmission part (such as friction, ripple resistance, etc.), B g is the viscous damping coefficient.

[0114] The conversion of the moment of inertia is mainly determined based on the product's parameter table. Generally, the spiral groove on the ball screw is ignored to roughly calculate the moment of inertia, and the influence of the moment of inertia of the inner ring of the bearing is ignored. In practice, these mechanisms will also affect the moment of inertia of the ball screw, so the moment of inertia calculated here is an approximate value.

[0115] The output shaft, coupling, and ball screw are all common rotating bodies. The formula for calculating the moment of inertia of a rotating body is:

[0116]

[0117] Among them, ρ is the material density of the rotor, L is the length of the rotor, D is the outer diameter of the rotor, d is the inner diameter of the rotor, and g is the gravitational acceleration, where g = 9.8 m / s 2 .

[0118] The calculation formula for converting the linear motion of an object into the moment of inertia of a ball screw is:

[0119]

[0120] Among them, m w is the workpiece mass, m T For the quality of the workbench.

[0121] The calculation of the viscous damping coefficient is mainly based on estimation and experimental testing, and there is often no specific calculation formula. The viscous damping coefficient of the ball screw is mainly determined by the damping inside the system and the damping outside the system. The internal damping is small and can often be ignored, and the impact of external damping is usually considered.

[0122] The stiffness formula of a rotating body is as follows:

[0123]

[0124] In the formula, K s is the rotational stiffness, M is the rotational torque, and θ is the rotation angle.

[0125] According to formula (13), the following expression holds:

[0126] T m -T d =K s [θ(t)-θ d (t)] (14)

[0127] Combining equations (9), (10), and (14), we can obtain:

[0128] r g Kθ d (s) = x(s)(J g s 2 +B g s+K s ) (15)

[0129] The transfer function of the mechanical transmission system is:

[0130]

[0131] From the transfer function, it can be seen that the ball screw mechanical transmission system is a typical second-order oscillation link. The state space expression of formula (14) is:

[0132]

[0133] 3) Study on coupling relationship of permanent magnet synchronous motor servo control system

[0134] Since the present invention adopts vector control to control the permanent magnet synchronous motor servo control system, it is necessary to transform the mathematical model of the permanent magnet synchronous motor from the abc coordinate system to the dq coordinate system. The mathematical model of the permanent magnet synchronous motor in the dq coordinate system is:

[0135]

[0136] Where, L d and L q are the dq axis inductance, i d and i q are dq axis current, u d and u q are dq axis voltage, R s is the stator phase resistance, ω r is the rotor angular velocity, L md is the d-axis excitation inductance, i f is the d-axis excitation current, p n is the pole pair number, T e and T L are the electromagnetic torque and load torque respectively, B is the viscous damping coefficient, and J is the moment of inertia.

[0137] According to the mathematical model of the permanent magnet synchronous motor and the ball screw, combined with equations (10), (14), and (18), the transfer function of the permanent magnet synchronous motor servo control system can be calculated. The coupling relationship between the permanent magnet synchronous motor and the ball screw can be intuitively understood through the transfer function relationship. The present invention combines vector control by drawing Figure 1 The structural block diagram of the permanent magnet synchronous motor servo control system based on ball screw shown in the figure intuitively demonstrates the coupling relationship between the ball screw and the permanent magnet synchronous motor, which facilitates the design of subsequent control methods and the construction of model simulation systems. Figure 1 In, K m is the torque coefficient of the permanent magnet synchronous motor, i is the reduction ratio, K s is the torque stiffness, B g is the equivalent viscous damping coefficient, J g To convert to equivalent moment of inertia, i t The distance the workbench travels when the motor rotates one circle, M g (s) is the equivalent disturbance of the ball screw mechanical transmission device, C i , C n and C p are current, speed, and position feedback coefficients, respectively, C E is the potential coefficient, G APR , G ASR and G ACR They are position, speed and current controllers respectively.

[0138] 2. Design of self-disturbance rejection control method for permanent magnet synchronous motor servo control system.

[0139] 1) Principle of Active Disturbance Rejection Control

[0140] In actual control systems, PID control has problems such as the inability to balance overshoot and rapidity, high-frequency oscillation interference caused by differentiation, and the inability to suppress the time-varying disturbance integral link. In the active disturbance rejection control (ADRC), the observation of each state and error of the system can be achieved through the extended observer. ADRC can compensate for disturbances and errors to achieve real-time control, and has a strong time-varying interference signal suppression function.

[0141] There are many adjustable parameters in ADRC, and each structure contains multiple adjustable parameters. ADRC consists of three parts: tracking differentiator, extended state observer, and nonlinear state error feedback rate. In actual engineering applications, most designs do not have a tracking differentiator link, so in actual applications, the parameters of these two parts are mainly adjusted.

[0142] 2) Active disturbance rejection control model

[0143] Since the first-order ADRC system has a simple structure and the second-order ADRC structure can be simplified to the first-order ADRC, the structural block diagram of the second-order ADRC of the present invention is as follows: Figure 4 shown. Figure 4 It can be seen that ADRC consists of three parts: TD, NLSEF and LESO. TD processes the input v0(t) signal and outputs the softened tracking signal v1(t) and differential signal v2(t); LESO uses the observed state variable and the output of TD to form error feedback, and directly uses the disturbance variable as the compensation signal of the control output; TD's tracking signal v1(t) and differential signal v2(t) and LESO's tracking observation signal z1(t) and differential observation signal z2(t) together constitute NLSEF's tracking deviation e1(t) signal and differential deviation e2(t) signal, and after NLSEF operation, it outputs u0(t), and u0(t) and LESO's z3(t) disturbance signal constitute the final control output.

[0144] In the field of motor control, first-order and second-order anti-disturbance control methods are often used. In the present invention, since a vector control framework is used, the idea is to decouple the current loop. In order to make the current loop respond quickly, the excitation and torque current loops use first-order ADRC, while the speed loop is affected by current coupling, load mutation and other disturbances, so the second-order ADRC is used.

[0145] The current speed is designed as follows:

[0146] ①Current loop design

[0147] From formula (18), the following calculation formula for torque current can be obtained:

[0148]

[0149] Let b0 = 1 / L q is the controller gain, is the total disturbance of the controller.

[0150] TD meets:

[0151]

[0152] LESO meets:

[0153]

[0154] NLSEF meets:

[0155]

[0156] In the design of the current loop, e0, e1, and e2 are error signals; v0 is the given current signal, and v1 is the softened tracking given current signal; z1 is the observed input signal, and z2 is the observed total disturbance signal; α0, α1, and α2 are tracking factors; δ0, δ1, and δ2 are filtering factors; β1 and β2 are correction factors; and b0 is the controller gain factor.

[0157] ②Speed ​​ring design

[0158] The motor dq axis inductance is the same. When the load torque is zero, the system speed loop open-loop transfer function is:

[0159]

[0160] Where: K n is the controller proportional coefficient, T pwm is the controller integral time constant, τ n is the influencing factor of the speed loop system, and s is the complex variable in the transfer function, called the complex frequency.

[0161] From formula (10), formula (18), and formula (23), we can get:

[0162]

[0163] Let b0 = 3p n 2 ψ f / 2(J+p n J g ) is the controller gain. In the present invention, the dq axis inductance of the permanent magnet synchronous motor is the same, so f = -[p n T d+(B+p n B g )ω r ] / (J+p n J g ) is the total disturbance of the controller.

[0164] The TD part meets the following requirements:

[0165]

[0166] LESO partially meets:

[0167]

[0168] NLSEF partially meets:

[0169]

[0170] In the speed loop design, v1 is the softened tracking signal of v0, v2 is the differential signal of v1, r0 is the speed factor, h0 is the filter factor, fhan function is the fastest comprehensive function, which can prevent the system from overshooting; z1 is the observed input signal, z2 is the observed differential signal, z3 is the observed disturbance signal, β 01 , β 02 , β 03 , δ are adjustable parameters; e1 and e2 are error signal and differential error signal respectively, β1, β2, α1, α2, δ are adjustable parameters.

[0171] ③ Position loop design

[0172] The position and speed can be designed together as a second-order ADRC controller. In order to meet the speed limiting requirement, the position loop of the present invention is implemented by a controller with the same simple proportion and output limiting as the traditional PID control.

[0173] 3. Control system hardware design.

[0174] The system of this embodiment adopts STM32F407IGT6 as a microprocessor, uses power MOSFET as a three-phase driver, selects IR2110 as the driving chip of the power MOSFET, selects HCPL-063A model high-speed optocoupler to isolate the control signal from the driving model, avoids hard connection between the control circuit and the driving circuit, selects 57BL75S10-230TF8 model permanent magnet synchronous motor with sinusoidal back electromotive force as the driving motor, and selects FSK40E1000-J model ball screw as the mechanical transmission device of the servo control system, which together constitute the permanent magnet synchronous motor hardware system. Figure 5 This is a specific control system hardware structure block diagram.

[0175] Figure 5 In the hardware system, the permanent magnet synchronous motor, microprocessor control circuit, signal isolation circuit, detection circuit, three-phase drive circuit, ball screw pair, power supply and host computer are composed of structures. The permanent magnet synchronous motor and ball screw constitute the entire hardware transmission system, the microprocessor control circuit, signal isolation circuit, detection circuit, etc. constitute the motor control circuit, and the three-phase drive circuit is the motor drive circuit. The main functions of each module are as follows:

[0176] The microprocessor control circuit is the core component for executing the control algorithm. This component has the functions of executing the control program, sending control instructions to the driver, feedback signal detection, realizing resource scheduling between multiple tasks, communicating with the host computer, and fault diagnosis.

[0177] The signal isolation circuit separates the control signal from the microprocessor from the actual drive signal, reducing the coupling relationship between the microprocessor control circuit and the three-phase drive circuit. At the same time, it can also isolate the Hall sensor signal from the microprocessor, thereby protecting the microprocessor control circuit.

[0178] Figure 5 In the detection circuit, there are five channels, namely, the Temp channel for collecting motor temperature, the V_Bus channel for collecting power supply voltage, the HALL_A / B / C channel for collecting Hall sensor position, and the I_A / B / C channel for collecting three-phase current. By collecting data from the five channels, the permanent magnet synchronous motor model in the digital space can be reconstructed to provide reliable data support for vector control.

[0179] The function of the three-phase drive circuit is to regularly turn on and off the DC power through the MOSFET, and finally convert it into Phase_A / B / C three-phase power to drive the motor to operate normally.

[0180] The power supply function is to supply power to each control module. The main function of the host computer is to receive the motor information collected by the microprocessor and display the motor information in real time. In addition, the host computer also has functions such as control program downloading, program debugging, and data transmission to the microprocessor.

[0181] 1) Microprocessor control circuit

[0182] In this embodiment, the permanent magnet synchronous motor servo control system uses STM32F407IGT6 as the microprocessor (MCU) chip. This chip uses ARM -M4 core is a high-performance microprocessor with DSP and floating-point computing functions. Its operating frequency can reach up to 168MHZ, and it has rich IIC, SPI, USART and CAN communication peripheral interfaces, and three 12-bit analog-to-digital converters (ADC) with a maximum sampling frequency of 2.4MSPS.

[0183] The chip has a high operating frequency and can support the vector operation and anti-disturbance operation of the system. Multiple communication interfaces are conducive to the communication between the motor controller and the host computer. Multiple 12-bit high-precision analog-to-digital converters provide a guarantee for the sampling of voltage, current and temperature in the present invention. The general timer provides support for motor rotor position detection and speed detection. The combination of timer and interrupt control makes multi-task scheduling of the program possible. Multiple advanced timers are conducive to the expansion of the system into the field of multi-motor control.

[0184] Based on the powerful computing function and rich peripheral interfaces of the chip, this embodiment uses the STM32F407IGT6 minimum system board as the MCU control module. In this experiment, advanced timer 1 is used to generate 3 PWM output signals. Due to the large number of chip pins in this system, the pin multiplexing function is not used here. This embodiment describes the functions of some pins of the system, as shown in Table 1.

[0185] Table 1 STM32F407IGT6 chip part pin interface

[0186]

[0187] In Table 1, the six PWM signals output by timer 1 will pass through the motor driver module to implement the motor speed regulation function. The three-phase current, voltage and temperature signals are polled and collected using the scanning mode of ADC1. The two GPIO peripherals control the motor start-up through software and hardware respectively.

[0188] 2) Signal isolation circuit

[0189] Since this permanent magnet synchronous motor servo control system generates PWM control signals according to program instructions through a microprocessor control circuit, the motor start and stop are controlled by controlling the PWM signal. The motor running speed is mainly determined by the output PWM duty cycle. The motor speed will affect the output result of the Hall sensor, and the output result of the Hall sensor will further affect the PWM duty cycle through the MCU. There is interference between the MCU and the three-phase driver and the Hall sensor. In order to avoid interference affecting the motor control effect, this system designs an optocoupler isolation circuit on the driver board.

[0190] Since PWM and HALL need to be isolated by optical coupling, the operating frequency of the selected optical coupling must be higher than the frequency of PWM and HALL outputs. In this embodiment, a high-speed optical coupling of model HCPL-063A is selected to meet the maximum operating frequency requirements of PWM and HALL, and the maximum input voltage is 5 V. Each chip contains two optical coupling units, which can realize a single optical coupling chip to control two PWM outputs.

[0191] 3) Signal sampling and conditioning circuit

[0192] In order to meet the requirements of the vector control algorithm, this embodiment collects the motor temperature through the Temp channel, the power supply voltage through the V_Bus channel, the Hall sensor position through the HALL_A / B / C channel, and the three-phase current through the I_A / B / C channel. The motor temperature of the Temp channel is detected to prevent the motor from burning out due to long-term operation or the heat generated; the voltage of the V_Bus channel and the three-phase current of the I_A / B / C channel are detected to reconstruct the mathematical model of the permanent magnet synchronous motor in the digital space to facilitate vector calculation; the rotor position of the HALL_A / B / C channel is detected to select the basic voltage space vector according to the sector where the rotor is located. The rotor speed can be observed according to the rotor position, and the rotor speed information facilitates the control system to adjust the motor speed.

[0193] ①Current detection circuit

[0194] The current detection method of this embodiment is to connect a 0.02Ω, 2W sampling resistor in series to each bridge arm of the driving circuit, and the sampling channels are I_A / B / C, and each sampling channel can collect current signals from 0 to 10A. The voltage signal at both ends of the sampling resistor is amplified by designing an operational amplifier and a peripheral addition and subtraction operation circuit, and finally the analog signal is output to the ADC module of the MCU through the I_A / B / C channel, and the current signal is collected by the ADC module.

[0195] The operational amplifier model used in this embodiment is the LM324 chip. This operational amplifier chip contains 4 operational amplifiers, three of which are used to collect three-phase current, and the non-inverting input terminal of the other operational amplifier is connected to the midpoint of two equal resistors. The two ends of these two resistors are connected to 3.3V and GND respectively, and the inverting input terminal is connected to the output, and a reference voltage of 1.65V is designed. Ia1 and Ia2 are the two ends of the sampling resistor of phase A. High-frequency interference signals can be filtered out through C10 and C11, and a voltage amplification circuit is formed through the operational amplifier, and finally output to the microcontroller after filtering through R12 and C12. The circuit has the following formula:

[0196]

[0197] Substituting the electronic device parameters into formula (27), it can be seen that the amplification factor is 4.12 times. Since the sampling resistor is 0.02Ω, the actual ADC converted digital value and the actual A phase current have the following relationship:

[0198] IaOUT=0.0824×Ia+1.65 (29)

[0199] ②Voltage detection circuit

[0200] The voltage detection of this system is to pass the output signal to the operational amplifier after resistor voltage division, and then output the signal to the MCU control circuit after voltage boost. The voltage detection circuit uses the LM358 operational amplifier chip with a small number of integrated operational amplifiers to design a voltage follower, which can meet the detection of voltage signals and avoid the waste of hardware resources caused by too many operational amplifiers.

[0201] In the voltage detection circuit, after the power supply voltage is divided by two resistors, the detection signal is input to the op amp terminal. The calculation method is the same as that of the current detection circuit. According to the characteristics of the op amp, the actual ADC converted digital quantity and the actual power supply voltage have the following relationship:

[0202] POWERout=0.05263×POWER+1.65 (30)

[0203] ③Other detection circuits

[0204] The system of this embodiment uses NTC thermistor to collect the motor temperature in the form of surface mount. The temperature collection circuit is to connect the thermistor in series with a precision resistor R54, with both ends connected to 3.3V and GND respectively, and the ADC collects the midpoint voltage. When the midpoint voltage detected by the ADC changes, it means that the temperature near the NTC resistor has changed. The ADC sampling value and the resistance value of the NTC thermistor satisfy the following formula:

[0205]

[0206] Among them, Rx is the resistance of the thermistor, and Tout is the value collected by ADC.

[0207] The resistance of the NTC thermistor will change with the change of the surface temperature of the motor. The resistance of the NTC thermistor is calculated based on the ADC sampling value, and the surface temperature of the motor can be further calculated through the relationship between the resistance value and temperature. The relationship between thermistor and temperature is as follows:

[0208]

[0209] Where B is the thermistor constant, R25 represents the thermistor resistance at 25°C, and T25 is 298.15K.

[0210] The system of this embodiment selects a two-pole permanent magnet synchronous motor, in which there are three Hall detection devices for detecting rotor position signals, which are evenly distributed in space and 120 degrees apart. The detection signal of the Hall sensor is in the form of a switch quantity, so the Hall signal is soft-connected to the control circuit through the signal isolation circuit, and the system interference is reduced through the signal isolation circuit. The rotor of the two-pole motor rotates one circle for 720 electrical degrees. Every 60 degrees of electrical angle, one HALL channel state will change, and the state of the HALL channel will remain at 180 degrees, so the HALL channel state changes 12 times in one circle. The three-way position detection signal after the optocoupler isolation circuit is input into a timer channel through the XOR function of the general timer. Since only one signal state of the Hall sensor changes each time, the three-way signal is XORed, and the input capture function of the timer can detect the running speed of the rotor, and the rotor position can be determined by the chip pin level.

[0211] 4) Three-phase driver circuit

[0212] Since the input impedance of MOSFET is high and the loss is small, the three-phase drive circuit adopts Infineon's IPD30N10S3L-34 N-channel power MOSFET as the three-phase driver switch tube in this embodiment. The MOSFET supports 100V working voltage, continuous working current of 30A, and instantaneous peak current of 120A. The IR2110 power driver is used to drive the power MOSFET, and the PWM signal output by the controller is boosted by bootstrap boosting, so as to control the MOSFET to turn on and off, save additional power modules, improve the working speed of MOSFET, and simplify the driver module design.

[0213] Adding dead time to the PWM signal can avoid the phenomenon of Q1 and Q2 tubes in the three-phase driver being directly connected. However, in the field of motor control, there are inevitably various interferences or MCU hardware and software failures, which will affect the PWM control signal to a certain extent. Therefore, the control system not only needs to set the dead time PWM output, but also can avoid the phenomenon of the upper and lower switch tubes in the same bridge arm being directly connected through the interlocking method at the hardware level.

[0214] 5) Power circuit

[0215] In the permanent magnet synchronous motor servo control system, the output power requirements of the control board and the driver board are different, so the power supply part is designed independently. Devices such as optocoupler modules, MOSFET drivers, op amp chips, and serial port peripherals require a 5V power supply voltage, MOSFET drivers require a 12V voltage to drive the power MOSFET on and off, and MCU and various weak current functions require a 3.3V power supply voltage.

[0216] 4. Control system software design.

[0217] Through the hardware model simulation research in the third step, it is clear that the speed current ADRC has a good control effect. The system of the present invention takes the speed current ADRC as the core of the software design.

[0218] In software design, the traditional sequential programming method is simple to program and is widely used in the field of motor programming. However, the speed current ADRC model is complex, and multiple control links make it difficult for the traditional sequential programming method to meet the real-time requirements of this system, and sequential programming will cause serious coupling of functional relationships between programs, which is not conducive to code expansion and reduces the MCU resource utilization. Therefore, the software design part of the present invention makes full use of the powerful interrupt function in the MCU chip, designs a multi-task scheduling mode, and realizes task scheduling through the motor state.

[0219] The main program design of the system of the present invention is used to initialize the design of each peripheral. The application design of this system includes multi-task scheduling, fault detection task design, motor control program design, etc. The motor control program design also includes detection function design, SVPWM algorithm implementation, speed current ADRC algorithm design, etc. The software design framework is as follows Figure 6 shown.

[0220] 1) Main program design

[0221] In order to modularize the various functions of the software and then schedule them uniformly through the multi-tasking mode, the main program design part is only for initialization design, and then it only needs to wait for the task request. After receiving the task request, the MCU will allocate hardware resources and execute the task.

[0222] System clock initialization is the basis for the normal operation of the microprocessor. Only when the system clock is configured for the peripheral device can the device work normally. This system selects the maximum clock frequency.

[0223] GPIO is the bridge connecting the microprocessor and external devices. After initializing GPIO, it can be used as an external interrupt receiving end to receive control instructions transmitted by external buttons; it can be used as an ADC input channel to receive power supply voltage and three-phase current signals; it can be used as a Hall sensor signal receiving end to calculate the motor position and speed through the timer input capture function and overflow interrupt function; it can be used as a communication interface to exchange information with the host computer to facilitate the visualization of data information.

[0224] Interrupt initialization is to clarify the order of resource allocation when multiple tasks apply for MCU resources at the same time. MCU divides interrupt priority into preemption priority and response priority. The interrupt priorities configured in this system are shown in Table 2.

[0225] Table 2 Peripheral interrupt priority

[0226]

[0227]

[0228] The ADC is initialized in independent mode, the cyclic scanning mode is enabled, the ADC frequency is configured to 21MHZ, the data is left-aligned, and the ADC analog conversion time is 15 / 21MHZ=0.71μs.

[0229] In the timer initialization, the initialization TIM1 is mainly used to generate three-way complementary and dead-zone PWM signals. TIM1 adopts the PWM center-aligned counting mode and sets the automatic reload value. When the timer increments from 0 to the reload value, an overflow update event is generated. After that, the timer decrements to 0 to generate an underflow update event, thereby forming a triangular carrier. By setting the comparison value of the triangular carrier, the PWM control signal is finally output.

[0230] 2) Multi-task scheduling

[0231] The multi-task scheduling of the present invention is related to the motor running state, and different task scheduling is performed according to the idle, running and fault states of the motor. When a single task sends a request, the MCU directly executes the task; when multiple tasks request MCU resources at the same time, the MCU will sort them according to the interrupt priority of each task, and execute the task with the higher priority first; if the priorities of the tasks are the same, for example, the priority of timer 3 and the external interrupt are the same, the tasks are executed in the order of their request.

[0232] When the motor is idle, the timer comparison value will be initialized to put the motor in a waiting state. When a motor start task is received, the motor state will be switched to a running state.

[0233] When the motor is in the running state, it starts waiting for task requests, such as the execution of the position loop, speed loop, and current loop tasks. The position loop has the slowest task request frequency, followed by the speed loop, and the current loop has the highest task request frequency. The request frequency of the current detection task is the same as that of the current loop. When the detected current value is updated, the current loop task will be updated. When there is a stop task request, the PWM output will be disabled and the motor will be returned to the idle state.

[0234] When executing the fault detection task, if a motor fault is found, the motor will be shut down directly until the fault is eliminated. Then the motor state will change to idle state and continue to receive motor start tasks.

[0235] Through the multi-task scheduling mode, the MCU resource utilization can be maximized, the program running efficiency can be improved, and by designing the program as tasks that need to be executed one by one, it is convenient for program expansion and debugging.

[0236] 3) Motor control program design

[0237] The programming of this permanent magnet synchronous motor servo control system is realized by applying for MCU resources and running task codes for multiple tasks. Although multiple tasks apply for MCU resources in a time-sharing manner, they have certain logical rules. Figure 7 Shown is a program flow chart between multiple tasks.

[0238] Figure 7 In the process, when the position loop task applies for MCU resources, it will calculate the deviation according to the given value and feedback information of the position, and run the position loop P control algorithm to update the given speed value output after limiting. If the MCU resources are not applied for, the position loop control algorithm will not be executed; when the speed loop applies for MCU resources, it will calculate the deviation according to the given value and feedback information of the rotor speed, and run the second-order speed anti-disturbance control algorithm to update the given q-axis current output after limiting. If the MCU resources are not applied for, the speed loop control algorithm will not be executed; when the current loop applies for MCU resources, it will first read the phase current sampling values ​​of phases A and B, and obtain the dq current feedback value through Clark and Park transformation, calculate the deviation according to the given value and feedback information of the q-axis current, and run the first-order current anti-disturbance control algorithm to generate a PWM control signal with a dead zone. If the MCU resources are not applied for, the current loop control algorithm and SVPWM algorithm will not be executed.

[0239] The motor control program design mainly includes three parts: detection function design, SVPWM design, and speed current ADRC algorithm design. Among them, the SVPWM algorithm is executed together with the current loop task. Figure 7 The design of the detection function and the speed and current ADRC algorithm are mainly introduced below.

[0240] ①Detection function design

[0241] The detection function is realized by collecting analog information of three-phase current, bus voltage and motor temperature through ADC1, and collecting rotor position and speed information through universal timer TIM3.

[0242] ADC1 is configured with a 21MHZ operating frequency and enables the cyclic scanning mode during initialization. In the motor control program design, the three-phase current, bus voltage, and motor temperature analog information are collected through cyclic scanning. After the conversion is completed, the current loop task is triggered.

[0243] During initialization, TIM3 sets the input capture and update interrupt functions, turns on edge triggering, and connects the CH1, CH2, and CH3 channels of TIM3 to the isolated Hall signals. The rotor position can be determined by reading the levels of the three Hall output signals. The pulse width of the three output signals of the Hall sensor is 180°, which is converted into a Hall input signal with a pulse width of 60 electrical degrees through the XOR module. The speed calculation task is triggered through the capture event of TIM3. The flow chart of the motor speed calculation task is shown in the figure. Figure 8 shown.

[0244] Figure 8 In the example, when TIM3 is interrupted, the Hall detection task is started to determine whether a capture interrupt occurs. If a capture interrupt occurs, the rotation direction of the rotor is determined based on the three Hall signals, and the electrical angle is updated. By determining whether the capture count overflows, the timer frequency division coefficient is dynamically adjusted, and the count value and the original frequency division coefficient are saved. The motor speed is calculated by the electrical angle increment, the capture count value under the increment, and the update count value; if no capture interrupt occurs, the timer generates an update event, the update count value is increased by one, and it is determined whether it exceeds the limit value. If not, the speed is updated and exited, otherwise the electrical angle increment is considered to be zero.

[0245] Since the single speed acquisition error is large, the present invention uses a simple sliding average algorithm to optimize the motor speed acquisition. The weight influencing factors of all time nodes of the simple sliding average are the same. The present invention uses a simple sliding average algorithm to optimize the sampling speed, and its calculation formula is:

[0246]

[0247] Among them, Y N is the output signal, S k is the original input signal, and n is the sliding window size.

[0248] ② Speed ​​current ADRC algorithm design

[0249] The speed current ADRC algorithm is the core control strategy of the present invention. ADRC is mainly composed of TD, LESO, and NLSEF structures. TD, LESO, and NLSEF in speed ADRC refer to equations (24), (25), and (26), respectively. TD, LESO, and NLSEF in current ADRC refer to equations (20), (21), and (22), respectively. Since the microprocessor executes the control program in a discrete manner, the control flow chart of speed ADRC is as follows: Fig. 9 As shown, the control flow chart of current ADRC is as follows Fig.10 shown.

[0250] Fig. 9In the figure, h represents the sampling time. Whenever the speed loop applies for MCU resources, the speed anti-disturbance control program is called, and the speed set value and feedback value are input into the second-order discrete TD module to output the softened speed and speed change rate; the speed, speed change rate, and total disturbance state are estimated through the second-order discrete ESO module; the deviation between the TD and ESO output speed and speed change rate is calculated through the second-order discrete NLSEF module and the control quantity is output.

[0251] Fig.10 In the program, whenever the current loop applies for MCU resources, the current self-disturbance rejection control program will be called, and the given value and feedback value of the current will be input into the first-order discrete TD module to output the softened current feedback value; the dq axis current and the total disturbance state quantity will be estimated through the first-order discrete ESO module; the deviation between TD and ESO output current will be calculated through the first-order discrete NLSEF module and the control quantity will be output.

[0252] 4) Fault detection task design

[0253] In order to prevent the motor from being damaged due to a fault, the present invention designs a high-frequency fault detection task. The present invention sets the execution frequency of the fault detection task to be the same as the execution frequency of the speed loop task. Fig.11 shown.

[0254] Fig.11 In the process, when the fault detection task applies for MCU resources, the fault flag will be cleared. Then, the faults such as over-temperature, over-voltage, under-voltage, and over-current will be judged in turn. If the threshold is exceeded, the corresponding flag will be set. If it does not exceed the threshold, the step of setting the corresponding flag will be skipped and the judgment will continue. After all faults are judged, check whether the fault flag is abnormal. If there is an abnormality, that is, a fault occurs, turn off the PWM output enable signal and stop the motor. Otherwise, skip this step and end the task directly.

[0255] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for controlling the speed and current of a ball screw permanent magnet synchronous motor based on active disturbance rejection control, characterized in that: The method comprises the following steps: S1: Construct the mathematical model of the permanent magnet synchronous motor and the ball screw pair, and then construct the permanent magnet synchronous motor servo control system model based on the coupling relationship between the two; S2: Construct an anti-disturbance control model for the permanent magnet synchronous motor servo control system, including: the excitation and torque current loops are designed using the first-order ADRC algorithm; the speed loop is designed using the second-order ADRC algorithm; The second-order ADRC algorithm is used to design the speed loop, specifically including: the motor dq axis inductance is the same, when the load torque is zero, the system speed loop open-loop transfer function is: Among them, K n is the controller proportional coefficient, T pwm is the controller integral time constant, τ n is the speed loop system influencing factor, s is the complex variable in the transfer function, called the complex frequency; The rigid body dynamics model of the ball screw pair mechanical transmission device is: Among them, J g is the total equivalent moment of inertia of the ball screw, T m Represents the output torque of the motor, T d Indicates the disturbance torque equivalent to the ball screw of the mechanical transmission part, B g is the viscous damping coefficient, θ(t) is the rotation angle of the permanent magnet synchronous motor, represents the derivative of θ(t); The mathematical model of permanent magnet synchronous motor in dq coordinate system is: Among them, L d and L q are the dq axis inductance, i d and i q are dq axis current, u d and u q are dq axis voltage, R s is the stator phase resistance, ω r is the rotor angular velocity, L md is the d-axis excitation inductance, i f is the d-axis excitation current, p n is the pole pair number, T e and T L are electromagnetic torque and load torque respectively, B is the viscous damping coefficient, and J is the moment of inertia of the rotor; The following expression is obtained from equations (1), (2) and (3): Among them, ψ f is the rotor flux; let b0=3p n 2 ψ f / 2(J+p n J g ) is the controller gain. Since the dq axis inductance of the permanent magnet synchronous motor is the same, f = -[p n T d +(B+p n B g )ω r ] / (J+p n J g ) is the total disturbance of the controller; TD part meets: LESO partially meets: NLSEF partially meets: In the speed loop design, v1 is the softened tracking signal of v0, v2 is the differential signal of v1, r0 is the speed factor, h0 is the filter factor, fhan(·) is the fastest comprehensive function; z1 is the observed input signal, z2 is the observed differential signal, z3 is the observed disturbance signal, β 01 , β 02 , β 03 , δ are adjustable parameters; e1 and e2 are error signal and differential error signal respectively, β1, β2, α1, α2, δ are adjustable parameters; δ1 and δ2 are filter factors; ε1 is the error signal; b0 is the controller gain factor, u is the system control variable group, u0 is the system initial control quantity; y is the actual output value of the test bench control system.

2. The ball screw permanent magnet synchronous motor speed and current control method according to claim 1, characterized in that: In step S1, a mathematical model of a permanent magnet synchronous motor is constructed, which specifically includes: the voltage equation of each phase winding of the permanent magnet synchronous motor is: Among them, u A 、u B and u C is the stator winding phase voltage, i A 、i B and i C is the phase current of the stator winding, e A 、e B and e C is the stator winding back electromotive force, R is the winding resistance, L and M are the stator winding self-inductance and the mutual inductance between windings, respectively, and L and M are both constants; Without considering mechanical loss, the electromagnetic torque of the permanent magnet synchronous motor is: Among them, T e is the electromagnetic torque, ω is the mechanical angular velocity of the permanent magnet synchronous motor; The mechanical motion equation of a permanent magnet synchronous motor is: Among them, T L is the load torque, B v is the damping coefficient, and J is the moment of inertia of the rotor.

3. The ball screw permanent magnet synchronous motor speed and current control method according to claim 1, characterized in that: In step S1, a mathematical model of a ball screw pair is constructed, specifically including: a rigid body dynamics model of a ball screw pair mechanical transmission device is: Among them, J g is the total equivalent moment of inertia of the ball screw, T m Represents the output torque of the motor, T d Indicates the disturbance torque equivalent to the ball screw of the mechanical transmission part, B g is the viscous damping coefficient, θ(t) is the rotation angle of the permanent magnet synchronous motor, represents the derivative of θ(t); The transfer function G(s) of the mechanical transmission system is: Among them, K s is the rotational stiffness, r g is the actual displacement of the worktable when the permanent magnet synchronous motor rotates one circle, s is the complex variable in the transfer function, called the complex frequency; From the transfer function G(s), it can be concluded that the ball screw mechanical transmission system is a typical second-order oscillation link, and the state space expression is: Where x is the displacement of the worktable, are the second-order derivative and first-order derivative of x respectively, y is the system output, i.e., the actual displacement of the workbench, B e is the external viscous damping coefficient of the ball screw system, J e is the moment of inertia of the ball screw, and u is the system control variable group.

4. The ball screw permanent magnet synchronous motor speed and current control method according to claim 3 is characterized in that: In step S1, a permanent magnet synchronous motor servo control system model is constructed, specifically including: using vector control to control the permanent magnet synchronous motor servo control system, converting the permanent magnet synchronous motor mathematical model from the abc coordinate system to the dq coordinate system, and the mathematical model of the permanent magnet synchronous motor in the dq coordinate system is: Among them, L d and L q are the dq axis inductance, i d and i q are dq axis current, u d and u q are dq axis voltage, R s is the stator phase resistance, ω r is the rotor angular velocity, L md is the d-axis excitation inductance, i f is the d-axis excitation current, p n is the pole pair number, T e and T L are electromagnetic torque and load torque respectively, B is the viscous damping coefficient, and J is the moment of inertia of the rotor; Combining equation (14) with the mathematical model of the permanent magnet synchronous motor and the ball screw pair, the transfer function of the permanent magnet synchronous motor servo control system is calculated, and the coupling relationship between the permanent magnet synchronous motor and the ball screw pair is obtained through the transfer function relationship.

5. The ball screw permanent magnet synchronous motor speed and current control method according to claim 4, characterized in that: In step S2, the first-order ADRC algorithm is used to design the excitation and torque current loops, specifically including: The calculation formula of the torque current is obtained from equation (14): Let b0 = 1 / L q is the controller gain, f=ω r (L d i d -L md i f ) / L q is the total disturbance of the controller; The tracking differentiator TD satisfies: The extended state observer LESO satisfies: The nonlinear state error feedback rate NLSEF satisfies: In the design of the current loop, e0, e1, and e2 are error signals; v0 is the given current signal, and v1 is the softened tracking given current signal; z1 is the observed input signal, and z2 is the observed total disturbance signal; y is the actual output value of the test bench control system; α0, α1, and α2 are tracking factors; δ0, δ1, and δ2 are filtering factors; β1 and β2 are correction factors, and k is the proportional coefficient; b0 is the controller gain factor; u is the system control variable group, and u0 is the system initial control quantity; The fall function is defined as follows: Among them, 0<α<1 and δ>0 are constants; NLSEF is a nonlinear controller, and its output control signal and the disturbance state observation of ESO together constitute the input signal of the controlled object.

6. A ball screw permanent magnet synchronous motor speed and current control system applicable to the method according to any one of claims 1 to 5, characterized in that: The system includes a transmission system, a control circuit and a motor drive circuit; the transmission system includes a permanent magnet synchronous motor and a ball screw pair; the control circuit includes a microprocessor, a signal isolation circuit and a detection circuit; The microprocessor is used to execute the control method, specifically including: executing the control program, sending control instructions to the motor drive circuit, feedback signal detection, realizing resource scheduling between multiple tasks, communicating with the host computer, and fault diagnosis; the signal isolation circuit is used to separate the control signal sent by the microprocessor from the actual drive signal, reduce the coupling relationship between the microprocessor and the motor drive circuit, and isolate the sensor signal from the microprocessor.

7. The ball screw permanent magnet synchronous motor speed and current control system according to claim 6, characterized in that: The motor drive circuit adopts a three-phase drive circuit, which regularly turns on and off the DC direct current through the MOSFET, and finally converts it into Phase_A / B / C three-phase electricity to drive the motor to run normally.

Images