Electric steering gear control system and control method

Abstract

The invention discloses an electric steering gear control system and a control method, wherein the control system comprises: an angular displacement sensor, a signal conversion module and an angle signal processing module, a multifunctional intelligent electric regulator, a motor state monitoring module, a voltmeter, a voltage monitoring module, an input display unit, a central processing unit, etc.; wherein the steering gear control method comprises the following steps: s1. establishing a mathematical model of a DC brushless motor; s2. establishing a mathematical model of a driver; s3. establishing a mathematical model of a reducer; s4. establishing a state space equation of the system; s5. designing a feedforward controller; s6. designing a sliding mode controller; the control system and the control method of the invention can greatly improve the anti-interference ability, control accuracy and safety performance of the existing steering gear servo system, and have important practical significance and application value.

Description

Technical Field

[0001] The invention patent relates to the field of automatic control, and specifically, to a control system and control method of an electric servo with high robustness, high reliability and high precision. Background Art

[0002] The electric steering gear system is a high-precision position servo system. It is an extremely important component of modern ships, warships, and submarines, and is an important actuator of the control system. The shipboard computer sends the angle command of the rudder deflection to the steering gear controller, drives the rudder to rotate, and then adjusts its own posture and motion trajectory. Ships and submarines will be affected by nonlinear time-varying environmental factors such as waves and surges when sailing on the sea or under the sea. The high-precision, high-robustness, and high-reliability steering gear servo control system can make ships and warships sail more stably and respond more sensitively, which can greatly improve navigation efficiency and quality and reduce the occurrence of accidents. Summary of the invention

[0003] The purpose of the present invention is to propose a control system and control method for an electric steering gear with high precision, high robustness and high reliability, which can greatly improve the anti-interference ability, control accuracy and safety performance of the existing steering gear servo system, and has important practical significance and application value.

[0004] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0005] An electric steering gear control system, comprising:

[0006] An angular displacement sensor, a signal conversion module and an angle signal processing module; the angular displacement sensor transmits the obtained angle information to the angle signal processing module through the signal conversion module, and the angle signal processing module processes the obtained angle signal through a filtering algorithm to finally obtain an actual terminal rudder angle signal;

[0007] Multifunctional intelligent electric regulator and motor status monitoring module; the multifunctional intelligent electric regulator transmits the motor temperature, armature current, motor speed and incremental rotation angle signals to the CAN signal receiving and sending module I through the CAN bus, and the CAN signal receiving and sending module I transmits the motor temperature and armature current signals to the motor status monitoring module; when the motor is in an abnormal state, the motor status monitoring module feeds back the monitoring signal to the central processing unit in real time;

[0008] A voltmeter and a voltage monitoring module; the voltmeter transmits the voltage of the regulated power supply to the voltage monitoring module through the signal conversion module; when the power supply is in an abnormal state, the voltage monitoring module feeds back a monitoring signal to the central processing unit in real time;

[0009] Input display unit; it includes a graphical display module, a command sending module and a parameter adjustment module; the input display unit obtains the steering gear angle, motor current, voltage and error information through the CAN signal receiving and sending module II, and displays and draws the data through the graphical display module; it sends the steering gear setting angle to the control system in real time through the command sending module, and adjusts some parameters of the control system through the parameter adjustment module;

[0010] Central processing unit; it includes an error processing module, a controller calculation module, a drive signal generation module, a system zero position calibration module and a fault and emergency processing module; the central processing unit obtains the control quantity of the motor through the error processing module, the controller calculation module and the drive signal generation module, and then transmits it to the multifunctional intelligent electric regulator through the CAN bus, thereby controlling the rotation of the motor; the system zero position calibration module is used to recalibrate the zero point when the system zero position deviates; the fault and emergency processing module is used to obtain signal feedback from the current monitoring module, the voltage monitoring module, the angle processing module, and the command signal input by the host computer in real time. When fault information appears or the host computer sends an emergency stop command, the fault information is reported and the relay is controlled to disconnect the motor power supply to achieve fault emergency processing.

[0011] The present invention also discloses a method for controlling an electric steering gear, comprising the following steps:

[0012] s1. Establish the mathematical model of brushless DC motor. The dynamic equation of brushless DC motor is:

[0013]

[0014] In the formula, U is the armature voltage, R is the resistance, L is the inductance, K e is the back electromotive force coefficient, ω is the motor angular velocity, J is the system moment of inertia, T l is the load torque, K r is the torque coefficient;

[0015] s2. Establish the mathematical model of the drive:

[0016] G PWM =K PWM ;

[0017] in, K PWM is the driver magnification, u a is the motor power supply voltage, u c is the PWM input voltage;

[0018] s3. Establish the mathematical model of the reducer: the reduction ratio of the reducer is K i ;

[0019] s4. Establish the state space equation of the system:

[0020]

[0021]

[0022]

[0023] Where u is the system input, u forward is a term that can be eliminated by feedforward control, d m is the interference in the same direction as the input, d mm is the interference perpendicular to the input direction;

[0024] s5. Design the feedforward controller as:

[0025]

[0026] In the formula is the motor mechanical time constant, θ is the actual angle value of the servo;

[0027] s6. Design the sliding mode controller, including the following steps:

[0028] s61. Design the synovial surface. According to the pole configuration method, the synovial surface of the system is designed as follows:

[0029] s=cx=c1x1+x2;

[0030] s62. Design the control law, let Where k·s is the exponential approach term, and ε·sat(s) is the constant speed approach term;

[0031] s63. Perform design system input and stability analysis, where the system input is:

[0032]

[0033] Where: m and δ mm They are d m and d mm The maximum value, c1,σ>0. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of a control system of the present invention;

[0035] Figure 2 Schematic diagram of the mechanical structure of the servo Figure Ⅰ ;

[0036] Figure 3 Schematic diagram of the zero adjustment method used by the system zero calibration module in the present invention Figure Ⅰ ;

[0037] Figure 4 Schematic diagram of the mechanical structure of the servo Figure II ;

[0038] Figure 5 Schematic diagram of the zero adjustment method used by the system zero calibration module in the present invention Figure II ;

[0039] Figure 6 A schematic diagram of the processing mechanism adopted by the fault and emergency processing module in the present invention;

[0040] Figure 7 is a control flow chart of the electric steering gear control system of the present invention;

[0041] Figure 8 This is a schematic diagram of the steering gear system control structure. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with embodiments.

[0043] like Figure 1 As shown, an electric steering gear control system of this embodiment includes:

[0044] An angular displacement sensor, a signal conversion module and an angle signal processing module; the angular displacement sensor includes but is not limited to a contactless magnetic encoder; the angular displacement sensor transmits the obtained angle information to the angle signal processing module through a signal conversion module (RS485-TTL, RS232-TTL, etc.), and the angle signal processing module processes the obtained angle signal through a suitable filtering algorithm, including but not limited to an anti-pulse interference average filtering method, to eliminate occasional pulse interference, improve smoothness, and finally obtain an actual terminal rudder angle signal within a 0.02° error range;

[0045] A multifunctional intelligent electric regulator, a CAN signal receiving and sending module I and a motor state monitoring module; the multifunctional intelligent electric regulator transmits the motor temperature, armature current, motor speed and incremental rotation angle signals to the CAN signal receiving and sending module I through the CAN bus, and the CAN signal receiving and sending module I transmits the motor temperature and armature current signals to the motor state monitoring module; when the motor is in an abnormal state, the motor state monitoring module feeds back the monitoring signal to the central processing unit in real time;

[0046] A voltmeter and a voltage monitoring module; the voltmeter transmits the voltage of the regulated power supply to the voltage monitoring module through the signal conversion module; when the power supply is in an abnormal state, the voltage monitoring module feeds back a monitoring signal to the central processing unit in real time;

[0047] Input display unit; it includes a graphical display module, a command sending module and a parameter adjustment module; the input display unit obtains the steering gear angle, motor current, voltage and error information through the CAN bus, and displays and plots the data through the graphical display module; it sends the steering gear setting angle to the control system in real time through the command sending module, and adjusts some parameters of the control system through the parameter adjustment module;

[0048] Central processing unit; it includes an error processing module, a controller calculation module, a drive signal generation module, a system zero position calibration module and a fault and emergency processing module; the central processing unit obtains the control quantity of the motor through the error processing module, the controller calculation module and the drive signal generation module, and then transmits it to the multifunctional intelligent electric regulator through the CAN bus, thereby controlling the rotation of the motor; the system zero position calibration module is used to recalibrate the zero point when the system zero position deviates; this system can adopt two methods of calibrating the zero position, one is to rely on the left and right mechanical limits of the servo structure, and obtain the angle value of the left and right extreme positions of the servo by monitoring the instantaneous stall current, and obtain the zero point angle according to the symmetry of the servo; the other is to rely on the left and right limit switches of the servo, and obtain the angle of the left and right extreme positions by detecting the signal changes when the servo hits the left and right limit switches, and then obtain the zero point position according to the symmetry of the servo. The specific implementation method is as follows Figure 3 , Figure 5 The fault and emergency processing module is used to obtain the signal feedback from the current monitoring module, the voltage monitoring module, the angle processing module, and the command signal input by the host computer in real time. When fault information appears or the host computer sends an emergency stop command, the fault information is reported and the relay is controlled to disconnect the motor power supply to achieve fault emergency processing. In this embodiment, the control process of the electric servo control system is as follows Figure 7 As shown, when obtaining the set angle, the angle input range is limited by limiting processing to prevent abnormal angle input. When the obtained angle sensor signal exceeds the reasonable range, the fault and emergency processing module is entered.

[0049] The present invention also discloses a method for controlling an electric steering gear, comprising the following steps:

[0050] The present invention also designs an electric steering gear control method, which can effectively suppress system interference caused by changes in controlled object parameters or external factors, and can greatly improve the robustness of the system.

[0051] The method mainly includes the following steps:

[0052] s1. Establish the mathematical model of brushless DC motor. The dynamic equation of brushless DC motor is:

[0053]

[0054] In the formula, U is the armature voltage, R is the resistance, L is the inductance, K e is the back electromotive force coefficient, ω is the motor angular velocity, J is the system moment of inertia, T l is the load torque, K r is the torque coefficient;

[0055] s2. Establish the mathematical model of the drive:

[0056] G PWM =K PWM ,

[0057] in, In the formula, K PWM is the driver magnification, u a is the motor power supply voltage, u c is the PWM input voltage.

[0058] s3. Establish the mathematical model of the reducer:

[0059] The reduction ratio of the reducer is K i .

[0060] s4. Establish the state space equation of the system:

[0061] Depend on:

[0062] L has a small coefficient relative to other terms and is ignored. And consider that after deceleration and simplification, we can get:

[0063]

[0064] in is the motor mechanical time constant.

[0065] Select the system state variable as x1 = θ d -θ, where θ d is the set angle value, θ is the actual angle value of the servo; the system input is the power supply voltage that can be adjusted according to the PWM wave duty cycle: u=U.

[0066] The state space equation of the system can be obtained as:

[0067]

[0068]

[0069]

[0070] Where u is the system input, u forward is a term that can be eliminated by feedforward control, dm is the interference in the same direction as the input, d mm is the interference perpendicular to the input direction.

[0071] s5. Feedforward controller design

[0072] Feedforward Controller Design:

[0073] s6. Sliding mode controller design

[0074] s61. Synovial surface design: The synovial surface of the system designed according to the pole configuration method is s=cx=c1x1+x2.

[0075] s62.Control law design: Let Among them, k·s is an exponential approach term, which can make the system reach the sliding surface in a limited time, and ε·sat(s) is a constant speed approach term, which can ensure that the system has a certain robustness on the sliding surface. Adjusting the k value can adjust the approach speed of the system's moving points, but too large a k value will cause severe vibration of the system. Increasing ε can increase the traversal speed of the system's moving points and speed up the approach speed, but too large a value will cause the system to overshoot and destroy the stability of the system. Replacing the sign(s) function with the saturated function sat(s) can greatly reduce the high-frequency vibration phenomenon of the system on the sliding surface.

[0076] s63. Design system input and stability analysis:

[0077]

[0078] Define the Lyapunov function as

[0079]

[0080] In order to satisfy the system to reach the equilibrium point within a limited time: According to Lyapunov's second law, the synovial controller needs to satisfy:

[0081] Where σ>0.

[0082] The design system input is:

[0083] u=-(CB) -1 (CAs)+(CB) -1 V,

[0084] Where V = -k·s-ε·sat(s),

[0085] Can get

[0086] Let ε = |CB|·δ m +|CB|·δ mm+σ>0,k>0

[0087] in:

[0088]

[0089] δ mm >|d mm |,

[0090] are the maximum values ​​of co-directional interference and anisotropic interference respectively.

[0091] It can satisfy

[0092] The system can reach stability in a finite time.

[0093] but:

[0094]

[0095] After adding feedforward control and PWM driver:

[0096] The system input is:

[0097]

[0098] 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 of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An electric steering gear control system, characterized in that: include: An angular displacement sensor, a signal conversion module and an angle signal processing module; the angular displacement sensor transmits the obtained angle information to the angle signal processing module through the signal conversion module, and the angle signal processing module processes the obtained angle signal through a filtering algorithm to finally obtain an actual terminal rudder angle signal; Multifunctional intelligent ESC and motor status monitoring module; The multifunctional intelligent electric regulator transmits the motor temperature, armature current, motor speed and incremental rotation angle signals to the CAN signal receiving and sending module I through the CAN bus, and the CAN signal receiving and sending module I transmits the motor temperature and armature current signals to the motor state monitoring module; when the motor is in an abnormal state, the motor state monitoring module feeds back the monitoring signal to the central processing unit in real time; A voltmeter and a voltage monitoring module; the voltmeter transmits the voltage of the regulated power supply to the voltage monitoring module through the signal conversion module; when the power supply is in an abnormal state, the voltage monitoring module feeds back a monitoring signal to the central processing unit in real time; Input display unit; it includes a graphical display module, a command sending module and a parameter adjustment module; the input display unit obtains the steering gear angle, motor current, voltage and error information through the CAN signal receiving and sending module II, and displays and draws the data through the graphical display module; It sends the servo setting angle to the control system in real time through the command sending module, and adjusts some parameters of the control system through the parameter adjustment module; Central processing unit; it includes an error processing module, a controller calculation module, a drive signal generation module, a system zero position calibration module and a fault and emergency processing module; the central processing unit obtains the control amount of the motor through the error processing module, the controller calculation module and the drive signal generation module, and then transmits it to the multifunctional intelligent electric regulator through the CAN bus, thereby controlling the rotation of the motor; The system zero position calibration module is used to recalibrate the zero point when the system zero position deviates; the fault and emergency processing module is used to obtain signal feedback from the current monitoring module, the voltage monitoring module, the angle processing module, and the command signal input by the host computer in real time. When fault information occurs or the host computer sends an emergency stop command, the fault information is reported and the relay is controlled to disconnect the motor power supply to achieve fault emergency processing.

2. A steering gear control method using the electric steering gear control system according to claim 1, characterized in that: The following steps are involved: s1. Establish the mathematical model of brushless DC motor. The dynamic equation of brushless DC motor is: In the formula, U is the armature voltage, R is the resistance, L is the inductance, K e is the back electromotive force coefficient, ω is the motor angular velocity, J is the system moment of inertia, T l is the load torque, K r is the torque coefficient; s2. Establish the mathematical model of the drive: G PWM =K PWM ; Among them, K PWM is the driver magnification, u a is the motor power supply voltage, u c is the PWM input voltage; s3. Establish the mathematical model of the reducer: the reduction ratio of the reducer is K i ; s4. Establish the state space equation of the system: Where u is the system input, u forward is a term that can be eliminated by feedforward control, d m is the interference in the same direction as the input, d mm is the interference perpendicular to the input direction; s5. Design the feedforward controller as: In the formula is the motor mechanical time constant, θ is the actual angle value of the servo; s6. Design the sliding mode controller, including the following steps: s61. Design the sliding membrane surface. According to the pole configuration method, the sliding membrane surface of the system is designed as: s=cx=c1x1+x2; s62. Design the control law, let Where k·s is the exponential approach term, and ε·sat(s) is the constant speed approach term; s63. Perform design system input and stability analysis, where the system input is: Where: m and δ mm They are d m and d mm The maximum value, c1,σ>0.

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