CN114977974B - A digital-analog hybrid architecture galvanometer motor system and drive control method - Google Patents

Abstract

The present invention discloses a digital-analog hybrid architecture galvanometer motor system and a drive control method. The system includes a digital control module, an analog drive module, a power module, a sampling detection module, a communication module and a motor body. The drive control method is given by a host computer, and transmitted to a DSP processor through a communication circuit. At the same time, the DSP processor receives the position information and current information collected by the sampling detection module, and after solving with a high-performance control algorithm, transmits the control signal to the analog drive module through a D/A conversion circuit, and outputs the amplified current signal to the armature winding of the galvanometer motor to achieve control of the galvanometer motor system. A double closed-loop control strategy with a current loop as an inner loop and a position loop as an outer loop is adopted to obtain higher control performance; higher dynamic performance and control accuracy are achieved in position control; the steady-state performance, dynamic performance and robustness of the system can be effectively improved to meet the technical requirements of laser marking.

Description

A digital-analog hybrid architecture galvanometer motor system and drive control method

Technical Field

The present application belongs to the field of high-precision galvanometer motor control, and specifically relates to a galvanometer motor system with a digital-analog hybrid architecture and a drive control method.

Background technique

Laser marking is a key technology in the current marking processing field. Compared with traditional marking methods, this technology has the advantages of low material consumption, fast marking speed, easy adjustment of marking content, and no pollution. Therefore, laser marking has gradually replaced traditional marking methods and is widely used in industrial production and life. The laser marking machine uses the principle of light reflection to control the direction of the laser light path by controlling the deflection angle of the plane mirror. The plane mirror here is called a galvanometer. The galvanometer is generally installed on a motor, and the deflection angle of the galvanometer is changed by the rotation of the motor, thereby controlling the deflection direction of the laser. This type of system is often called a galvanometer motor system.

As an excellent vector scanning device, the galvanometer motor system is the basic equipment for controlling the deflection of the galvanometer and realizing laser marking technology. Its linearity, rapidity, anti-interference ability and other performance will become key factors affecting the quality of laser marking imaging. With the continuous development of the laser industry, the demand for high-performance galvanometer motor systems has also continued to increase. The galvanometer motor system has also been mainly used in industrial fields such as laser marking and laser welding, and can now be applied to laser-based biomedical applications. Since each application has different design requirements for response speed, positioning accuracy, size and cost, with the development of the galvanometer motor system, there are several different topologies and technologies for the main components in the system to meet the performance indicators required in different fields.

At present, the research of galvanometer motor systems by major foreign companies and research institutions is at the international leading level. The bandwidth of the most advanced galvanometer system can reach several thousand Hz, its unit step response time can reach 100us, and the repeatability accuracy can reach 2urad. However, the development of galvanometer motor systems in China is relatively late. At present, the unit step response time of the systems designed by most domestic galvanometer companies is greater than 300us, and the repeatability accuracy is about 8urad. These key performances are somewhat different from those of foreign countries.

Therefore, designing the topological architecture of digital controller and analog driver for the galvanometer motor system and studying high-performance control methods can make up for the shortcomings of pure analog control system that cannot adopt high-performance control algorithms and the large torque fluctuation of pure digital control system, and can improve its response speed and positioning accuracy and other performance, which is of great value to the development of domestic galvanometer motor control systems.

Summary of the invention

The main purpose of the present invention is to propose a digital-analog hybrid architecture galvanometer motor system and a drive control method, which has fast dynamic response and high positioning accuracy, and improves the control performance of the system.

In order to achieve the above-mentioned purpose, a digital-analog hybrid architecture galvanometer motor system is proposed, the system comprises a digital control module, an analog drive module, a power supply module, a sampling detection module, a communication module and a motor body, the output end of the motor body is connected to the input end of the sampling detection module, the output end of the sampling detection module is connected to the input end of the digital control module, the output end of the communication module is connected to the input end of the digital control module, the output end of the digital control module is connected to the input end of the analog drive module, the output end of the analog drive module is connected to the input end of the motor body, and the power supply module is electrically connected to the digital control module and the analog drive module respectively for power supply;

The communication module includes a host computer and a communication circuit, the output end of the host computer is connected to the input end of the communication circuit, and the output end of the communication circuit is connected to the input end of the digital control module;

The sampling detection module includes a current sampling circuit and a position sampling circuit; the input end of the current sampling circuit is connected to the motor body, the output end of the current sampling circuit is connected to the input end of the first A/D conversion circuit, and the output end of the first A/D conversion circuit is connected to the input end of the digital control module; the input end of the position sampling circuit is connected to the motor body, the output end of the position sampling circuit is connected to the input end of the second A/D conversion circuit, and the output end of the second A/D conversion circuit is connected to the input end of the digital control module;

The digital control module includes a DSP processor, and the digital control module is connected to the input end of the analog drive module through a D/A conversion circuit;

The analog drive module includes a power operational amplifier, and the output end of the power operational amplifier is connected to the motor body;

The motor body is a galvanometer motor body.

As a preferred embodiment of the present invention, the current sampling circuit of the present invention includes a Hall current sensor, which collects the rotor current information of the galvanometer motor and transmits it to the DSP processor; the position sampling circuit includes a photoelectric position sensor, which collects the lens position information of the galvanometer motor and transmits it to the DSP processor.

As a preferred embodiment of the present invention, the analog drive module of the present invention includes a power operational amplifier U1, a resistor R1, a resistor R2 and a resistor R3. The output end of the power operational amplifier U1 is connected to the galvanometer motor. The output end of the D/A conversion circuit is connected to the positive input end of the power operational amplifier U1. A resistor R2 is arranged between the negative input end of the power operational amplifier U1 and the galvanometer motor. The resistor R1 and the resistor R3 are grounded.

As a preferred embodiment of the present invention, the D/A conversion circuit of the present invention is a chip of model LTC1668; the first A/D conversion circuit is a current loop A/D converter, a chip of model AD9220, and the second A/D conversion circuit is a position loop A/D converter, using an 18-bit A/D conversion chip, a chip of model AD7641.

As a preferred embodiment of the present invention, the DSP processor model of the present invention is TMS320C28346; the communication module adopts the communication protocol of XY2-100.

In particular, the present invention also discloses a drive control method based on the digital-analog hybrid architecture galvanometer motor system, wherein the drive control method is performed by a host computer giving a target instruction, which is transmitted to a DSP processor through a communication circuit. At the same time, the DSP processor receives position information and current information collected by a sampling detection module, and after solving the information using a high-performance control algorithm, transmits the control signal to an analog drive module through a D/A conversion circuit, and outputs the amplified current signal to the armature winding of the galvanometer motor, thereby realizing control of the galvanometer motor system.

The drive control method adopts a topological structure of a digital control module and an analog drive module, and adopts a double closed-loop control strategy in which the inner loop is a current loop and the outer loop is a position loop;

The dual closed-loop control strategy uses the current loop as the inner loop, and the current loop is composed of a galvanometer motor body, a current sampling circuit, a first A/D conversion circuit, a DSP processor, a D/A conversion circuit, and an analog drive module to form a closed loop in sequence; when the galvanometer motor current loop is controlled, the current given signal is compared with the motor armature winding current collected by the current sampling circuit to obtain the error of the current signal, and the controller output signal is obtained after being modulated by the PI controller of the DSP processor, and the obtained digital signal is converted into an analog signal through the D/A conversion circuit and input into the analog drive module, and the analog drive module amplifies the voltage signal into a current signal to realize direct control of the armature current;

The dual closed-loop control strategy uses the position loop as the outer loop, and the position loop is composed of a galvanometer motor body, a position sampling circuit, a second A/D conversion circuit, a DSP processor, a D/A conversion circuit, and an analog drive module in sequence to form a closed loop; when the galvanometer motor position loop is controlled, the position command signal sent by the host computer and the position signal collected by the position sampling circuit are solved and modulated by the sliding mode control algorithm with an extended state observer in the DSP processor to obtain the command signal of the current loop, which is output to the current loop PI controller of the DSP processor.

As a preferred embodiment of the present invention, the control method of the position loop of the present invention specifically includes:

Step 1: According to the position command given by the host computer, a third-order differential tracker is used to obtain the tracking signal of the position input and its first-order differential and second-order differential, in preparation for the differential signal input required by the sliding mode controller in step 3;

Step 2: According to the position signal measured by the position sensor of the position sampling circuit, a nonlinear extended state observer is used to obtain the differential value of the position feedback signal and the total disturbance signal required for sliding mode control, so as to compensate for the system disturbance. The extended state observer is obtained according to the mechanical motion equation of the motor;

Step 3: Based on the given signal of the galvanometer motor position, the tracking signal of the first-order differential and second-order differential of the given position obtained by the differential tracker, the total disturbance signal obtained by the extended state observer, the actual position signal and the differential observation value of the actual position, a sliding mode controller is used to obtain the output of the position loop, that is, the given value of the current loop.

As a preferred embodiment of the present invention, step 1 of the present invention specifically includes:

The differential tracker is used to approximate the differential of the signal. The expression of the third-order differential tracker is as follows:

In the formula, _v1 is the position command given by the host computer, _x1 is the position tracking signal, _x2 is the tracking signal of the position differential, _x3 is the tracking signal of the second-order position differential, and r is the parameter of the third-order differential tracker. In the actual galvanometer motor control system, the discrete form of the third-order differential tracker is used for control, and its expression is as follows:

Wherein, v(k) is the position command, x ₁ (k) is the tracking signal of the position, x ₂ (k) is the tracking signal of the position differential, x ₃ (k) is the tracking signal of the second-order differential of the position, k is the sampling time, and h is the sampling step.

As a preferred embodiment of the present invention, the motor model expression of step 2 of the present invention is as follows:

Where, θ is the motor rotor position, J is the motor moment of inertia, _Bm is the damping coefficient, _Te is the electromagnetic torque, _Td is the load torque, _Kte is the torque coefficient, and _ia is the winding current;

It is transformed into the state equation as shown below:

Where _x1 and _x2 are the motor rotor position and motor rotor angular velocity respectively, and y is the output of the galvanometer motor drive control system, that is, the actual position of the galvanometer motor lens; definition is the parameter in the algorithm, and is defined is the sum of the disturbances inside and outside the system, and expands it into a new state variable x ₃ , defining Expand the original system into a new linear system, whose state space expression is as follows:

In order to compensate the disturbance of the system, we define is the final control quantity of the system, and the system can be transformed into a linear integral control system as shown in the following formula:

According to the principle of extended state observer, a third-order nonlinear state extended observer is designed for the galvanometer motor system to observe the system state and perform disturbance compensation. The final expression is:

Where e(k) is the error between the position observation and the actual value, z ₁ (k) and z ₂ (k) are the observation values of the galvanometer motor position feedback and its differential, respectively, z ₃ (k) is the total disturbance observation value of the system, k is the sampling time, h is the sampling step, β ₁ , β ₂ , β ₃ are the gains of the extended state observer, which are related to the observer bandwidth, fal(e,α,δ) is a continuous power function with a linear segment near the origin, where α and δ are the parameters of the function. The use of this type of function can avoid the high-frequency chatter phenomenon of the traditional extended state observer, and its expression is:

As a preferred embodiment of the present invention, the design method of the sliding mode controller in step three of the present invention is as follows:

The sliding surface function is defined as:

Among them, c is the adjustment parameter of the sliding surface, e is the error between the position setting and the position feedback, is the differential of the error between the position setting and the position feedback; the exponential approach law is selected so that the control signal can approach the sliding surface as quickly as possible, that is:

Among them, ε and k are the coefficients of the exponential reaching law, where k determines the approaching speed before reaching the sliding surface, and ε determines the approaching speed when reaching the sliding surface. In order to reduce the jitter problem in sliding mode control, the saturation function sat(s,δ) is used to replace the sign function, where δ is the linear segment parameter of the saturation function. The expression of the saturation function is as follows:

According to the mathematical model of the galvanometer motor and the model of the extended state observer, the control law of the position loop controller can be obtained:

Wherein, _xr is the given value of the position signal, _z1 , _z2 , _z3 are the observed values of the position signal, the position differential signal and the total disturbance signal obtained by the extended state observer, and u is the output of the position loop controller.

The beneficial effects of the present invention are:

(1) The present invention adopts a digital-analog hybrid architecture in terms of topological structure, that is, an architecture combining a digital controller and an analog driver. Compared with a purely analog topological architecture, the digital-analog hybrid architecture can adopt a more complex control algorithm to obtain better control performance; compared with a purely digital topological architecture, the digital-analog hybrid architecture can reduce torque fluctuations and improve the quality of the output signal to the motor, which has a significant effect on obtaining better response speed and control accuracy;

(2) In terms of drive control structure, in view of the fact that the galvanometer motor requires high dynamic response performance, a dual closed-loop control system is adopted, in which the inner loop is a current loop and the outer loop is a position loop. Compared with the traditional three-loop control of position loop, speed loop and current loop, the dual closed-loop control can improve the dynamic response capability of the system while ensuring the system accuracy;

(3) In the position loop controller, sliding mode control with an extended state observer is adopted. While utilizing the ability of sliding mode control to quickly approach the sliding surface to improve the response speed of the system, the extended state observer is utilized to improve the anti-interference ability of the system, thus making up for the shortcomings of traditional PID control, such as slow response speed and insufficient anti-interference ability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the overall structure of the digital-analog hybrid galvanometer motor system of the present invention;

FIG2 is a schematic diagram of a linear power operational amplifier transconductance connection structure of an analog drive module of the present invention;

FIG3 is a structural diagram of a sliding mode control strategy with an extended state observer according to the present invention;

FIG4 is a flow chart of the overall control of the galvanometer motor system proposed in the present invention;

FIG5 is a flow chart of the position loop control of the galvanometer motor system proposed in the present invention.

Detailed ways

The preferred embodiments of the present invention are described below in conjunction with the drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other if there is no conflict.

Embodiment 1

In this example, a digital-analog hybrid architecture galvanometer motor system and a drive control method are provided to meet the needs of drive control of a digital-analog hybrid architecture galvanometer motor system. In the control part, a dual closed-loop control strategy with a current loop as an inner loop and a position loop as an outer loop is adopted to obtain higher control performance; traditional PID control is adopted in the current loop, and sliding mode control with an expanded state observer is adopted in the position loop, pursuing higher dynamic performance and control accuracy in position control; the use of such a digital-analog hybrid control method can effectively improve the steady-state performance, dynamic performance and robustness of the system, and can meet the requirements of laser marking technology.

The present invention is a type of digital-analog hybrid galvanometer motor drive control system, and the hardware circuit of its drive control structure is shown in Figure 1, a digital-analog hybrid architecture galvanometer motor system, the system includes a digital control module, an analog drive module, a power module, a sampling detection module, a communication module and a motor body, the output end of the motor body is connected to the input end of the sampling detection module, the output end of the sampling detection module is connected to the input end of the digital control module, the output end of the communication module is connected to the input end of the digital control module, the output end of the digital control module is connected to the input end of the analog drive module, the output end of the analog drive module is connected to the input end of the motor body, and the power module is electrically connected to the digital control module and the analog drive module respectively for power supply.

As shown in Figure 1, the power module adopts an isolated power supply mode. The main power supply is a 30V DC power supply. The 30V DC power supply is converted into a ±5V power supply through the URA2405S-6WR3 isolated power supply to power digital chips such as A/D conversion chips and D/A conversion chips; the 5V DC voltage is converted into 3.3V, 1.8V, and 1.2V DC power supplies through the TPS767D318PWP type regulated power supply and the MIC29302BU type regulated power supply to power the DSP processor and its peripheral circuits; the 30V DC voltage is converted into a ±15V power supply through the URA2415S-6WR3 isolated power supply to power various operational amplifiers in the system.

As shown in Figure 1, the digital control module is based on the DSP processor. The digital control module is mainly composed of a DSP chip and peripheral circuits such as a crystal oscillator circuit, a reset circuit, a JTAG circuit, and a CAN communication circuit. The DSP chip uses the TMS320C28346 of the C2000 series of TI, USA. Its clock frequency can reach 300MHz, and it has a SARAM of up to 258K×16 and 88 reusable GPIO pins, which can realize high-performance control algorithms.

The analog drive module of the present invention is based on a linear power operational amplifier, and the analog drive module includes a power operational amplifier U1, a resistor R1, a resistor R2 and a resistor R3. The output end of the power operational amplifier U1 is connected to the galvanometer motor, the output end of the D/A conversion circuit is connected to the positive input end of the power operational amplifier U1, a resistor R2 is arranged between the negative input end of the power operational amplifier U1 and the galvanometer motor, and the resistor R1 and the resistor R3 are grounded. The linear power operational amplifier adopts the OPA549 high-voltage and high-current operational amplifier of TI Company of the United States, and its power supply voltage range can reach 60V, and the maximum long-term output current can reach 8A, which can meet the needs of the galvanometer motor system. In order to be able to directly control the armature current of the galvanometer motor, as shown in Figure 2, the linear power operational amplifier adopts a transconductance connection method. At this time, the linear power operational amplifier can convert a constant input voltage into a constant output current, and its amplification formula is:

Wherein, _Ag is the amplification factor of OPA549, U _IN is the input voltage, I _OUT is the output current, R ₁ , R ₂ , and R ₃ are the resistance elements in the external circuit. The connection method of the external circuit is shown in FIG2 .

The sampling and detection module includes a current sampling circuit and a position sampling circuit. The current sampling circuit is composed of a Hall current sensor, an A/D conversion chip and its peripheral circuits. It collects the galvanometer motor rotor current information and transmits it to the DSP processor. The position sampling circuit is composed of a photoelectric position sensor, an A/D conversion chip and its peripheral circuits. It collects the lens position information and transmits it to the DSP processor.

For the current detection module, the Hall current sensor uses LEM's CASR 6-NP, which detects the current passing through the motor winding based on the Hall effect principle. The maximum measurable current range of CASR 6-NP can reach 12A, and its measurement accuracy is relatively high; the A/D conversion chip uses ADI's AD9237, which is a 20MSPS, low-power, 12-bit resolution, parallel A/D conversion chip with a chip select port, which can meet the high-frequency response requirements of the current loop.

For the position detection module, a photoelectric position sensor is used to detect the position information of the galvanometer motor, which has the characteristics of small size, small temperature drift, high linearity, etc. The A/D conversion chip uses the AD7641 of ADI, which is a parallel A/D conversion chip with 2MSPS, 18-bit resolution and chip select port, which can meet the high-precision requirements of the position loop.

For the communication module, the communication circuit uses the MAX3095 receiver from MAXIM, and the communication protocol uses the XY2-100 protocol commonly used in the galvanometer industry. The transmission signals of this protocol include clock signals, synchronization signals, and position data signals. It uses three-wire real-time communication and adopts differential signals for transmission, which ensures the accuracy of the system transmission data.

Figure 3 is a structural diagram of the sliding mode control strategy with an extended state observer proposed in the present invention. The driving control method of the digital-analog hybrid architecture galvanometer motor system proposed in the present invention adopts a dual closed-loop control strategy with a current loop as an inner loop and a position loop as an outer loop. Compared with the traditional three-loop control of position loop, speed loop and current loop, the dual closed-loop control can improve the dynamic response capability of the system while ensuring the system accuracy.

Figure 4 is a general control flow chart of the galvanometer motor system obtained according to the control strategy structure diagram. During the control process, the command signal sent by the host computer is input into the third-order differential tracker to obtain the command tracking signal and its differential signal; the actual position signal fed back by the position sensor is input into the extended state observer to obtain the position and its differential signal and the total disturbance signal; the error obtained after comparison is input into the sliding mode controller to obtain the initial output signal of the position loop, and then after compensation of the total disturbance observation signal, the final output signal of the position loop, that is, the input command signal of the current loop, is obtained; after the current loop controller compares the input command signal and the actual current signal fed back by the current sensor, the obtained error is input into the PI controller, and then after amplification by the linear power operational amplifier, the final output current is output to the galvanometer motor winding to complete the control process.

For the current loop of this control strategy, the traditional PI controller is used to control the armature current of the motor. Its main feature is that the linear power operational amplifier adopts a transconductance connection to convert the voltage signal into a current signal, thereby realizing direct control of the armature winding current to improve the control accuracy of the motor.

For the position loop of this control strategy, a sliding mode control method with an extended state observer is used for control, and its control flow chart is shown in Figure 5. Using sliding mode control with an extended state observer as the controller of the position loop can not only utilize the fast approaching ability of the sliding mode control to improve the response speed of the galvanometer motor system, but also utilize the disturbance compensation ability of the extended state observer to improve the anti-interference ability of the system, so as to comprehensively improve the dynamic and steady-state performance of the galvanometer system.

As shown in Figure 5, the specific control process of the sliding mode control algorithm of the position loop with extended state observer is as follows:

Step 1: According to the position command given by the host computer, a third-order differential tracker is used to obtain the tracking signal of the position input and its first-order differential and second-order differential, in preparation for the differential signal input required by the sliding mode controller in the next stage.

Since the pure differential link cannot be realized physically, the classical differentiator or differential tracker is often used to approximate the signal differentiation. The differential tracker can eliminate the high-frequency noise easily generated by the classical differentiator while obtaining a better approximation effect. The expression of the third-order differential tracker is as follows:

In the formula, _v1 is the position command given by the host computer, _x1 is the position tracking signal, _x2 is the tracking signal of the position differential, _x3 is the tracking signal of the second-order position differential, and r is the parameter of the third-order differential tracker. In the actual galvanometer motor control system, the discrete form of the third-order differential tracker is used for control, and its expression is as follows:

Wherein, v(k) is the position command, x ₁ (k) is the tracking signal of the position, x ₂ (k) is the tracking signal of the position differential, x ₃ (k) is the tracking signal of the second-order differential of the position, k is the sampling time, and h is the sampling step.

Step 2: According to the position signal measured by the position sensor, a nonlinear extended state observer is used to obtain the differential value of the position feedback signal and the total disturbance signal required for sliding mode control to compensate for the system disturbance. The extended state observer needs to be obtained based on the mechanical motion equation of the motor. The motor model expression is as follows:

In the formula, θ is the motor rotor position, J is the motor moment of inertia, _Bm is the damping coefficient, _Te is the electromagnetic torque, _Td is the load torque, _Kte is the torque coefficient, and _ia is the winding current; after converting it into a state equation, it is shown as follows:

Where _x1 and _x2 are the motor rotor position and motor rotor angular velocity respectively, and y is the output of the galvanometer motor drive control system, that is, the actual position of the galvanometer motor lens; definition is the parameter in the algorithm, and is defined is the sum of the disturbances inside and outside the system, and expands it into a new state variable x ₃ , defining The original system can be expanded into a new linear system, whose state space expression is as follows:

In order to compensate the disturbance of the system, we define is the final control quantity of the system, and the system can be transformed into a linear integral control system as shown in the following formula:

According to the principle of extended state observer, a third-order nonlinear state extended observer is designed for the galvanometer motor system to observe the system state and perform disturbance compensation. The final expression is:

Where e(k) is the error between the position observation and the actual value, z ₁ (k) and z ₂ (k) are the observation values of the galvanometer motor position feedback and its differential, respectively, z ₃ (k) is the total disturbance observation value of the system, k is the sampling time, h is the sampling step, β ₁ , β ₂ , β ₃ are the gains of the extended state observer, which are related to the observer bandwidth, fal(e,α,δ) is a continuous power function with a linear segment near the origin, where α and δ are the parameters of the function. The use of this type of function can avoid the high-frequency chatter phenomenon of the traditional extended state observer, and its expression is:

Step 3: Based on the given signal of the galvanometer motor position, the tracking signal of the first-order differential and second-order differential of the given position obtained by the differential tracker, the total disturbance signal obtained by the extended state observer, the actual position signal and the differential observation value of the actual position, a sliding mode controller is used to obtain the output of the position loop, that is, the given value of the current loop. The design method of the sliding mode controller is as follows.

The sliding surface function is defined as:

Among them, c is the adjustment parameter of the sliding surface, e is the error between the position setting and the position feedback, is the differential of the error between the position setting and the position feedback. Selecting the exponential approach law can make the control signal approach the sliding surface as quickly as possible, that is:

Among them, ε and k are the coefficients of the exponential reaching law, where k determines the approaching speed before reaching the sliding surface, and ε determines the approaching speed when reaching the sliding surface. In order to reduce the jitter problem in sliding mode control, the saturation function sat(s,δ) is used to replace the sign function, where δ is the linear segment parameter of the saturation function. The expression of the saturation function is as follows:

According to the mathematical model of the galvanometer motor and the model of the extended state observer, the control law of the position loop controller can be obtained:

Wherein, _xr is the given value of the position signal, _z1 , _z2 , _z3 are the observed values of the position signal, the position differential signal and the total disturbance signal obtained by the extended state observer, and u is the output of the position loop controller.

The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and offsets to this specification. Such modifications, improvements and offsets are suggested in this specification, so such modifications, improvements and offsets still belong to the spirit and scope of the exemplary embodiments of this specification.

In addition, it will be understood by those skilled in the art that various aspects of this specification may be illustrated and described by a number of patentable categories or situations, including any new and useful process, machine, product or combination of substances, or any new and useful improvements thereto. Accordingly, various aspects of this specification may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". In addition, various aspects of this specification may be represented as a computer product located in one or more computer-readable media, which includes computer-readable program code.

It should be noted that if the descriptions, definitions, and/or usage of terms in the supplementary materials of this specification are inconsistent or conflicting with the contents of this specification, the descriptions, definitions, and/or usage of terms in this specification shall prevail.

Finally, it should be understood that the embodiments in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, the alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims (9)

1. A digital-analog hybrid architecture galvanometer motor system is characterized in that: the system comprises a digital control module, an analog driving module, a power module, a sampling detection module, a communication module and a motor body, wherein the output end of the motor body is connected with the input end of the sampling detection module, the output end of the sampling detection module is connected with the input end of the digital control module, the output end of the communication module is connected with the input end of the digital control module, the output end of the digital control module is connected with the input end of the analog driving module, the output end of the analog driving module is connected with the input end of the motor body, and the power module is respectively and electrically connected with the digital control module and the analog driving module for supplying power;

The communication module comprises an upper computer and a communication circuit, wherein the output end of the upper computer is connected with the input end of the communication circuit, and the output end of the communication circuit is connected with the input end of the digital control module;

The sampling detection module comprises a current sampling circuit and a position sampling circuit; the input end of the current sampling circuit is connected with the motor body, the output end of the current sampling circuit is connected with the input end of the first A/D conversion circuit, and the output end of the first A/D conversion circuit is connected with the input end of the digital control module; the input end of the position sampling circuit is connected with the motor body, the output end of the position sampling circuit is connected with the input end of the second A/D conversion circuit, and the output end of the second A/D conversion circuit is connected with the input end of the digital control module;

the digital control module comprises a DSP processor and is connected with the input end of the analog driving module through a D/A conversion circuit;

the analog driving module comprises a power operational amplifier U1, a resistor R2 and a resistor R3, wherein the output end of the power operational amplifier U1 is connected with the galvanometer motor, the output end of the D/A conversion circuit is connected with the positive input end of the power operational amplifier U1, a resistor R2 is arranged between the negative input end of the power operational amplifier U1 and the galvanometer motor, and the resistor R1 and the resistor R3 are grounded;

the motor body is a galvanometer motor body.

2. The digital-to-analog hybrid architecture galvanometer motor system of claim 1, wherein: the current sampling circuit comprises a Hall current sensor, and the Hall current sensor collects current information of a rotor of the galvanometer motor and transmits the current information to the DSP; the position sampling circuit comprises a photoelectric position sensor, and the photoelectric position sensor collects lens position information of the galvanometer motor and transmits the lens position information to the DSP.

3. The digital-to-analog hybrid architecture galvanometer motor system of claim 1, wherein: the model of the D/A conversion circuit is a chip of LTC 1668; the first A/D conversion circuit is a current loop A/D converter and is a chip with the model of AD9220, the second A/D conversion circuit is a position loop A/D converter, and an 18-bit A/D conversion chip and a chip with the model of AD7641 are adopted.

4. The digital-to-analog hybrid architecture galvanometer motor system of claim 1, wherein: the model of the DSP processor is TMS320C28346; the communication module adopts an XY2-100 communication protocol.

5. A driving control method based on the digital-analog hybrid architecture galvanometer motor system as set forth in any one of claims 1-4, characterized in that:

The driving control method is characterized in that a target instruction is given by an upper computer and is transmitted to a DSP (digital signal processor) through a communication circuit, meanwhile, the DSP receives position information and current information acquired by a sampling detection module, after the position information and the current information are resolved by a high-performance control algorithm, a control signal is transmitted to an analog driving module through a D/A (digital-to-analog) conversion circuit, and the amplified current signal is output to an armature winding of a galvanometer motor, so that the control of the galvanometer motor system is realized;

the driving control method adopts a topological structure of a digital control module and an analog driving module, and adopts a double closed-loop control strategy with an inner loop as a current loop and an outer loop as a position loop;

The double closed-loop control strategy takes a current loop as an inner loop, and the current loop sequentially comprises a vibrating mirror motor body, a current sampling circuit, a first A/D conversion circuit, a DSP processor, a D/A conversion circuit and an analog driving module to form a closed loop; when the current loop of the galvanometer motor is controlled, comparing a current given signal with the current of the armature winding of the motor acquired by a current sampling circuit to obtain an error of a current signal, modulating the error by a PI controller in a DSP processor to obtain a controller output signal, converting the obtained digital signal into an analog signal by a D/A conversion circuit and inputting the analog signal into an analog driving module, and amplifying a voltage signal into the current signal by the analog driving module to realize direct control of the armature current;

The double closed-loop control strategy takes a position loop as an outer loop, and the position loop sequentially comprises a vibrating mirror motor body, a position sampling circuit, a second A/D conversion circuit, a DSP processor, a D/A conversion circuit and an analog driving module; when the position loop of the vibrating mirror motor is controlled, a position command signal sent by an upper computer and a position signal acquired by a position sampling circuit are resolved and modulated through a sliding mode control algorithm with an extended state observer in a DSP processor, a command signal of a current loop is obtained, and the command signal is output to a current loop PI controller of the DSP processor.

6. The driving control method of the galvanometer motor system of the digital-analog hybrid architecture according to claim 5, wherein the control method of the position ring specifically comprises:

Step one: according to a position instruction given by an upper computer, a third-order differential tracker is adopted to obtain a tracking signal of the position input and the first-order differential and the second-order differential thereof, so as to prepare for differential signal input required by the sliding mode controller in the third step;

Step two: according to the position signal measured by the position sensor of the position sampling circuit, a nonlinear extended state observer is adopted to obtain the differential value and the total disturbance signal of a position feedback signal required by sliding mode control, so that the system disturbance is compensated, and the extended state observer is obtained according to the mechanical motion equation of the motor;

Step three: and obtaining the output of the position loop, namely the given value of the current loop by adopting a sliding mode controller according to the given signal of the position of the vibrating mirror motor, the tracking signals of the first-order differential and the second-order differential, which are obtained by the differential tracker, the total disturbance signal, the actual position signal and the differential observation value of the actual position, which are obtained by the extended state observer.

7. The method of driving and controlling a galvanometer motor system according to claim 6, wherein the first step specifically comprises:

The signal is approximately differentiated by a differential tracker, and the expression of the third-order differential tracker is as follows:

Wherein v ₁ is a position instruction given by an upper computer, x ₁ is a position tracking signal, x ₂ is a position differential tracking signal, x ₃ is a position second differential tracking signal, and r is a parameter of a third differential tracker; in an actual galvanometer motor control system, a discrete form of a third-order differential tracker is adopted for control, and the expression is as follows:

Where v (k) is a position command, x ₁ (k) is a position tracking signal, x ₂ (k) is a position differential tracking signal, x ₃ (k) is a position second order differential tracking signal, k is a sampling time, and h is a sampling step.

8. The driving control method of the galvanometer motor system of the digital-analog hybrid architecture according to claim 7, wherein the motor model expression of the second step is as follows:

Wherein θ is the motor rotor position, J is the motor moment of inertia, B _m is the damping coefficient, T _e is the electromagnetic torque, T _d is the load torque, K _te is the moment coefficient, and i _a is the winding current;

This is expressed as the equation of state as follows:

Wherein x ₁ and x ₂ are the position and the angular speed of the motor rotor respectively, and y is the output of the vibrating mirror motor drive control system, namely the actual position of the lens of the vibrating mirror motor; definition of the definition For parameters in the algorithm, defineFor the sum of the internal disturbance and the external disturbance of the system, and expanding the sum into a new state variable x ₃, the definition is thatExpanding the original system into a new linear system, and the state space expression is as follows:

to compensate for disturbances in the system, a definition is made of For the final control amount of the system, the system is changed into a linear integral control system as shown in the following formula:

According to the principle of an extended state observer, a third-order nonlinear state extended observer is designed for a galvanometer motor system to observe the system state and perform disturbance compensation, and the final expression is as follows:

where e (k) is the error between the position observation value and the actual value, z ₁ (k) and z ₂ (k) are the observation values of the position feedback and the differentiation of the vibrating mirror motor, z ₃ (k) is the total disturbance observation value of the system, k is the sampling time, h is the sampling step length, β ₁、β₂、β₃ is the gain of the extended state observer, and related to the observer bandwidth, fal (e, α, δ) is a continuous power function with a linear section near the origin, where α, δ are parameters of the function, and the use of such function can avoid the high frequency flutter phenomenon of the traditional extended state observer, and the expression is:

9. The driving control method of a digital-analog hybrid architecture galvanometer motor system according to claim 8, wherein the design method of the sliding mode controller in the third step is as follows:

Defining a sliding mode surface function as follows:

Where c is the adjustment parameter of the slide surface, e is the error between position setting and position feedback, Differentiating the error between the position setting and the position feedback; the exponential approach law is chosen so that the control signal can approach the slip plane as soon as possible, namely:

Wherein epsilon and k are coefficients of an exponential approach law, wherein k determines the approach speed before reaching the sliding surface, and epsilon determines the approach speed when reaching the sliding surface; to reduce jitter problems in sliding mode control, the sign function is replaced with a saturation function sat (s, δ), where δ is a linear segment parameter of the saturation function, the expression of which is as follows:

according to the mathematical model of the galvanometer motor and the model of the extended state observer, the control law of the position loop controller can be obtained:

Where x _r is the given value of the position signal, z ₁、z₂、z₃ is the observed value of the position signal, the position differential signal, and the total disturbance signal obtained by the extended state observer, and u is the output of the position loop controller.