A multi-channel proportional valve controller and control method based on master-slave control architecture

Abstract

The present invention provides a multi-channel proportional valve controller and control method based on a master-slave control architecture. The multi-channel proportional valve controller includes components such as a microcontroller, a programmable array logic, a multi-channel current amplification drive function module, a multi-channel current sampling function module, a pressure and flow feedback function module, an analog input function module, a digital input function module, a digital output function module, a communication function module, and a power supply function module. The master-slave control architecture is adopted, and the master controller and the slave controller cooperate in processing and parallel calculation, which can effectively improve the signal acquisition rate, data processing capability, pressure and flow control accuracy of the proportional valve, and can meet the requirements of driving multiple proportional valves at the same time. The current closed-loop control algorithm based on the integrator anti-saturation can effectively ensure the current control accuracy and response, and improve the control performance of the proportional valve.

Description

Technical Field

[0001] The present invention belongs to the field of electro-hydraulic proportional valve control, and in particular relates to a multi-channel proportional valve controller and a control method based on a master-slave control architecture. Background Art

[0002] A proportional valve controller is an electronic device used to provide a specific performance current to the proportional solenoid and to perform open-loop or closed-loop regulation of the proportional valve. Its performance and reliability directly affect the control accuracy and stability of the proportional valve.

[0003] Traditional proportional valve controllers are generally divided into two types: analog circuit control and single microcontroller control. Analog circuit proportional valve controllers generally use a large number of discrete electronic components based on circuit logic to complete current amplification and driving functions. Their power amplifiers generally work in the linear region to amplify current, and there is no microcontroller inside. Proportional valve controllers based on single microcontrollers introduce digital microcontrollers, which are generally composed of signal input, digital processing, power output and other parts. They can perform simple signal acquisition, data processing and digital operations, but due to processing power and driving power limitations, it is difficult to drive multiple proportional valves at the same time. In addition, traditional proportional valve controllers generally only have current sampling and closed-loop control to ensure current output accuracy, and lack pressure or flow closed-loop feedback functions, resulting in problems such as low pressure or flow control accuracy.

[0004] The analog circuit proportional valve controller uses discrete electronic components based on circuit logic combination to complete the current amplification and driving functions. It has the characteristics of complex circuits and large size. In addition, its power amplifier tube generally works in the linear region, which has problems such as high power consumption, high temperature, and poor reliability.

[0005] Although the proportional valve controller based on a single microcontroller has introduced a digital microcontroller to effectively reduce power consumption and temperature rise, the microcontroller is not only responsible for data storage and digital calculations, but also has to undertake multiple tasks such as data communication, signal acquisition, data processing and power drive. This leads to shortcomings such as slow signal acquisition, slow data processing, poor control accuracy and insufficient power drive. It is difficult to meet the needs of high-speed signal acquisition, complex mathematical operations and multi-way proportional valve drive of complex electro-hydraulic proportional control systems.

[0006] In addition, due to the lack of pressure and flow closed-loop control functions, the traditional proportional valve controller often leads to a rapid decrease in pressure or flow control accuracy as the proportional valve body structure deforms and ages. In addition, the current closed-loop control algorithm inside the existing proportional valve adopts basic proportional integral control, ignoring the current amplification drive circuit package and nonlinear characteristics, which easily leads to the proportional valve control response speed being full or out of control. Summary of the invention

[0007] Facing the problem of complex electro-hydraulic control systems, traditional proportional valve controllers cannot handle advanced control algorithms or have insufficient driving capabilities. The present invention proposes a multi-channel proportional valve controller and control method based on a master-slave control architecture. The present invention is a solution proposed based on the defects of existing proportional valve controllers. It adopts a master-slave control architecture, and the master controller and the slave controller cooperate in processing and parallel calculation, which can effectively improve the signal acquisition rate, data processing capability, pressure and flow control accuracy of the proportional valve, and can meet the requirements of driving multiple proportional valves at the same time.

[0008] The technical solution of the present invention is as follows:

[0009] The present invention first provides a multi-channel proportional valve controller based on a master-slave control architecture, the multi-channel proportional valve controller comprising:

[0010] A microcontroller, which serves as a main controller and is used to realize the communication function, data storage, pressure closed-loop control and flow closed-loop control of the multi-channel proportional valve controller;

[0011] Programmable array logic, as a slave controller, is responsible for high-speed signal acquisition, external signal input, and multi-channel current amplification and driving functions; the programmable array logic communicates with the microcontroller through the internal SPI bus to exchange data and execute the control commands of the microcontroller;

[0012] The multi-channel current amplification driving function module amplifies and outputs the current according to the control signal of the programmable array logic, and then drives the proportional valve. The multi-channel current amplification driving function module meets the requirements of driving multiple proportional valves at the same time;

[0013] The multi-channel current sampling function module collects the current output current in real time and adjusts the current in real time according to the current closed-loop control algorithm inside the microcontroller to ensure the current control accuracy;

[0014] The pressure and flow feedback function module uses precision operational amplifiers and analog-to-digital conversion chips to collect the current control pressure or flow in real time, and adjusts the pressure and flow output in real time according to the pressure and flow closed-loop control algorithm inside the microcontroller to ensure the pressure and flow control accuracy;

[0015] The analog input function module has two input modes: current and voltage, which can meet the requirements of receiving external control input signals;

[0016] Digital input function module, receiving external enable control signal to control the working state of the proportional valve;

[0017] The digital output function module receives the instruction from the programming array logic and completes the digital output to output the working status of the proportional valve controller;

[0018] The communication function module completes the communication function between the proportional valve controller and the outside.

[0019] On the other hand, the present invention also provides a multi-channel proportional valve control method based on the controller, which comprises the following steps:

[0020] 1) The user initializes, sets parameters, and sets the microcontroller through the communication function module, and sends the pressure or flow command to the microcontroller. The microcontroller generates a pressure or flow reference value, and solves the pressure and flow control deviation at the current moment based on the pressure and flow measurement values ​​collected by the pressure and flow feedback function module, and solves the drive current target value at the next moment based on the pressure and flow closed-loop control algorithm, and transmits it to the programmable array logic through the SPI bus for bottom-level driving;

[0021] 2) The programmable array logic compares the deviation between the current measurement value collected by the multi-channel current sampling function module and the current target value, and solves the PWM output duty cycle at the next moment based on the current closed-loop control algorithm;

[0022] 3) The multi-channel current amplification drive function module adjusts the MOS tube opening and closing time according to the solved PWM duty cycle to adjust the output current, and further controls the pressure and flow of the proportional valve.

[0023] Furthermore, in step 2), the current closed-loop control algorithm adopts a current proportional-integral (PI) control method based on integrator anti-saturation.

[0024] The current proportional-integral control method based on integrator anti-saturation takes into account the saturation nonlinear characteristics of the current amplification drive circuit and limits the upper and lower limits of the current controller output to u max and u min , when the current controller u c >u max , the controller only accumulates negative deviation values; when the current controller u c min , the controller only accumulates positive deviation values, thereby limiting the current controller control quantity u c Staying in the saturation zone for a long time can improve the response speed of the proportional valve.

[0025] ​Compared with the prior art, the master-slave control architecture proposed in the present invention can ensure that the master controller, i.e., the microcontroller, and the slave controller, i.e., the programmable array logic, can perform parallel calculations. The microcontroller focuses on implementing complex algorithms for pressure and flow closed loops, and the programmable array logic focuses on high-speed signal acquisition and digital signal processing, effectively improving the control capability and efficiency of the proportional valve and meeting the driving requirements of the multi-channel proportional valve. The pressure and flow feedback function module described in the present invention collects the current pressure and flow control signals in real time and corrects them through the control algorithm. Even if the proportional valve body structure is deformed or the coil heats up severely, causing resistance changes, the pressure and flow control accuracy of the proportional valve can be guaranteed by the closed-loop control algorithm. At the same time, the current closed-loop control algorithm based on the anti-saturation of the integrator can effectively guarantee the current control accuracy and response, and improve the control performance of the proportional valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural block diagram of a multi-channel proportional valve controller system based on a master-slave control architecture of the present invention;

[0027] Figure 2 This is the circuit schematic diagram of the analog input function module;

[0028] Figure 3 It is the circuit schematic diagram of the multi-channel current amplification driving function module;

[0029] Figure 4 It is the circuit schematic diagram of the multi-channel current sampling function module;

[0030] Figure 5 This is the circuit schematic diagram of the power supply function module;

[0031] Figure 6 Flowchart of the control method of a multi-channel proportional valve controller based on a master-slave control architecture;

[0032] Figure 7 This is the block diagram of current PI control based on integrator anti-saturation.

[0033] In the figure, communication function module 1, microcontroller 2, analog input function module 3, programmable array logic 4, digital input function module 5, multi-channel current sampling function module 6, digital output function module 7, multi-channel current amplification drive function module 8, pressure and flow feedback function module 9, data storage function module 10, and power supply function module 11. DETAILED DESCRIPTION

[0034] The present invention is further described and illustrated below in conjunction with specific embodiments. The embodiments are merely exemplary of the present disclosure and do not define the scope of limitation. The technical features of each embodiment of the present invention may be combined accordingly without conflicting with each other.

[0035] like Figure 1 As described, an embodiment of the present invention provides a multi-channel proportional valve controller based on a master-slave control architecture. The controller adopts a master-slave control architecture, and the master controller and the slave controller cooperate in processing and parallel calculation, which can effectively improve the signal acquisition rate, data processing capability, pressure and flow control accuracy of the proportional valve, and can meet the requirements of simultaneous driving of multiple proportional valves. The multi-channel proportional valve controller based on the master-slave control architecture proposed by the present invention mainly includes a microcontroller 2, a programmable array logic 4, a multi-channel current amplification drive function module 8, a multi-channel current sampling function module 6, a pressure and flow feedback function module 9, an analog input function module 3, a digital input function module 5, a digital output function module 7, a communication function module 1, a data storage function module 10 and a power supply function module 11.

[0036] In a specific embodiment of the present invention, the microcontroller 2 is used as the main controller, and mainly performs functions such as upper-level decision-making, parameter configuration, external communication, and pressure and flow closed-loop control algorithm implementation of the proportional valve controller. The algorithm implementation of the microcontroller includes pressure closed-loop control and flow closed-loop control, which are independently implemented in the microcontroller 2.

[0037] In a specific embodiment of the present invention, the programmable array logic 4 is a system slave controller, which is mainly responsible for the underlying high-speed signal acquisition, external signal input, multi-channel current amplification drive and other functions. The programmable array logic 4 and the microcontroller 2 communicate through the internal SPI bus to exchange data and execute the control commands of the microcontroller 2. The programmable array logic 4 has powerful digital signal processing, high-speed sampling frequency and high driving power capabilities, and can receive external analog input and digital input commands and respond. The programmable array logic 4 solves the corresponding driving current size according to the pressure or flow command decided by the microcontroller, and adjusts the PWM duty cycle based on the current size, and sends it to the multi-channel current amplification function module 8 through its I / O port, and finally outputs the target current size to drive the proportional valve. The current closed-loop control can be realized inside the programmable array logic 4, and the current deviation can be detected and corrected in real time to ensure the current output accuracy.

[0038] like Figure 3As shown, the multi-channel current amplification driving function module 8 of the present invention adopts a PWM switch control method, performs current amplification and output according to the control signal of the programmable array logic, and then drives the proportional valve, which can meet the requirements of driving multiple proportional valves at the same time. In a specific embodiment, the multi-channel current amplification driving circuit function module 8 adopts a PWM switch-type drive MOS tube closed mode. When PWM is high, the high level is amplified by the triode to reach the gate drive voltage of the MOS tube, and then drives the MOS tube to turn on. At this time, the circuit forms a closed loop, and the current flows out from the power supply to the source of the MOS tube, and then flows out from the drain of the MOS tube, through the precision sampling resistor, and flows to the proportional valve, thereby driving the proportional valve to work normally. When PWM is low, the MOS tube is disconnected, and the circuit is in an open circuit state. No current passes through the proportional valve, and the proportional valve stops working. The PWM duty cycle received by the multi-channel current amplification function module 8 directly determines the output current. The higher the duty cycle, the larger the output current, and the lower the duty cycle, the smaller the output current. The lower limit of the current output by the current amplification driving circuit function module is zero ampere, and the upper limit of the current depends on the power supply voltage and the loop resistance.

[0039] like Figure 4 As shown, the multi-channel current sampling function module 6 adopts an integrated precision current detection operational amplifier to collect the current output current in real time, and adjust the current in real time according to the current closed-loop control algorithm inside the microcontroller to ensure the current control accuracy. In a specific embodiment, the multi-channel current sampling function module 6 adopts a precision sampling resistor + current integrated operational amplifier mode, and the precision sampling resistor is connected in series in the current amplification drive circuit. When the driving current passes through the precision sampling resistor, a voltage drop will be formed at both ends of it. The current integrated operational amplifier collects the voltage drop at both ends of the precision sampling resistor and performs voltage operational amplifier, and converts the analog quantity acquisition signal into a digital signal through the A / D analog-to-digital conversion chip and transmits it to the programmable array logic 4 through the I / O port to reversely deduce the current driving current size at the current moment and perform subsequent current PI closed-loop control.

[0040] The pressure and flow feedback function module 9 uses a precision operational amplifier and an analog-to-digital conversion chip to collect the current control pressure or flow in real time, and adjust the pressure and flow output in real time according to the pressure and flow closed-loop control algorithm inside the microcontroller to ensure the pressure and flow control accuracy. Specifically, the pressure and flow feedback function module 9 is used to collect the pressure or flow feedback signal output by the current proportional valve, and convert it into a digital quantity through the A / D analog-to-digital conversion chip, transmit it to the microcontroller through the I / O port, and complete the pressure and flow closed-loop control inside the microcontroller 2 to ensure the pressure and flow control accuracy of the proportional valve in real time.

[0041] like Figure 2As shown, the analog input function module 3 has two input modes, current and voltage, to meet the needs of receiving external control input signals and to receive external analog control signals. In a specific embodiment of the present invention, the analog input function module 3 passes through a conditioning circuit composed of a protection device and a precision resistor, converts the signal to an A / D analog-to-digital conversion chip, and then transmits it to the programmable array logic 4.

[0042] In a specific embodiment of the present invention, the digital quantity input function module 5 mainly receives an external enable control signal to control the working state of the proportional valve. The digital quantity output function module 7 mainly receives instructions issued by the programming array logic and completes digital quantity output to output the working state of the proportional valve controller. That is, the digital quantity output function module 7 receives instructions through the I / O port of the programmable array 4 and outputs the current working state of the proportional valve.

[0043] In a specific embodiment of the present invention, the communication function module 1 has RS232, CAN bus and USB communication interfaces to complete the communication function between the proportional valve controller and the outside. The data storage function module 10 is used to store the data collected by the signal and the historical commands of the control output.

[0044] The power supply function module 11 is powered by an external 24V power supply, which is converted into the voltage required by each electronic component through a voltage conversion chip to ensure the normal operation of each electronic component. Figure 5 As shown in FIG. 1 , a schematic diagram of a power supply function module circuit in a specific embodiment of the present invention is shown. The 24V power supply voltage can be converted into a 12V target voltage through a 24V-12V voltage conversion chip; the 12V target voltage can be converted into a 5V target voltage through a 12V-5V voltage conversion chip. The 24V, 12V, and 5V voltages are used to maintain the normal operation of various electronic components.

[0045] The present invention proposes a multi-channel proportional valve controller control method based on a master-slave control architecture, such as Figure 6As shown, the user can perform initialization settings, parameter settings, and ramp settings on the microcontroller 2 through the communication function module 1, and send pressure or flow instructions to the microcontroller 2. The microcontroller 2 generates a pressure or flow reference value, and solves the pressure and flow control deviation at the current moment based on the pressure and flow measurement values ​​collected by the pressure and flow feedback function module 9, and solves the drive current target value at the next moment based on the pressure and flow closed-loop control algorithm, and transmits it to the programmable array logic 4 through the SPI bus for bottom-level driving. The programmable array logic 4 compares the deviation between the current measurement value collected by the multi-channel current sampling function module 9 and the current target value, and solves the PWM output duty cycle at the next moment based on the current closed-loop control algorithm. The multi-channel current amplification drive function module adjusts the MOS tube opening and closing time according to the solved PWM duty cycle to adjust the output current, and further performs pressure and flow control on the proportional valve. As a preferred embodiment, the current closed-loop control algorithm adopts a current proportional-integral (PI) control method based on integrator anti-saturation. The specific control block diagram is shown in FIG. Figure 7 As shown, the traditional current PI control algorithm simply eliminates the static error of the current. However, when the integral effect continues to accumulate and the current drive circuit reaches its limit, the current controller reaches saturation. When the current has a reverse deviation, the controller output u c Gradually exit the saturation zone. When the controller exits the saturation zone, the current controller cannot respond quickly to the external input control quantity, affecting the control performance of the proportional valve and even causing the proportional valve to lose control. The proposed PI control method based on integrator anti-saturation can take into account the saturation nonlinear characteristics of the current amplifier drive circuit and limit the upper and lower limits of the current controller output to u max and u min , when the current controller u c >u max , the controller only accumulates negative deviation values; when the current controller u c min , the controller only accumulates positive deviation values, which can limit the control amount u of the current controller c Staying in the saturation zone for a long time improves the control performance of the proportional valve.

[0046] In order to solve the problems of slow signal acquisition rate, poor control accuracy, insufficient driving capability and the like of existing controllers, the present invention adopts a master-slave control architecture and reasonably divides tasks to give full play to the advantages of complex control algorithm implementation of microcontrollers and high-speed signal acquisition and multi-channel current amplification driving capabilities of programmable array logic, and adds a pressure and flow feedback function module to detect and feedback the current pressure and flow in real time, thereby realizing closed-loop control of pressure and flow, and greatly meeting the high-precision and high-speed control requirements of simultaneous driving of multiple proportional valves.

[0047] ​The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A multi-channel proportional valve controller based on a master-slave control architecture, characterized in that: The multi-channel proportional valve controller comprises: A microcontroller, which serves as a main controller and is used to realize the communication function, data storage, pressure closed-loop control and flow closed-loop control of the multi-channel proportional valve controller; Programmable array logic, as a slave controller, is responsible for high-speed signal acquisition, external signal input, and multi-channel current amplification and driving functions; the programmable array logic communicates with the microcontroller through the internal SPI bus to exchange data and execute the control commands of the microcontroller; The multi-channel current amplification driving function module amplifies and outputs the current according to the control signal of the programmable array logic, and then drives the proportional valve. The multi-channel current amplification driving function module meets the requirements of driving multiple proportional valves at the same time; The multi-channel current sampling function module collects the current output current in real time and adjusts the current in real time according to the current closed-loop control algorithm inside the microcontroller to ensure the current control accuracy; The pressure and flow feedback function module uses precision operational amplifiers and analog-to-digital conversion chips to collect the current control pressure or flow in real time, and adjusts the pressure and flow output in real time according to the pressure and flow closed-loop control algorithm inside the microcontroller to ensure the pressure and flow control accuracy; The analog input function module has two input modes: current and voltage, which can meet the requirements of receiving external control input signals; Digital input function module, receiving external enable control signal to control the working state of the proportional valve; The digital output function module receives the instruction from the programming array logic and completes the digital output to output the working status of the proportional valve controller; The communication function module completes the communication function between the proportional valve controller and the outside.

2. The multi-channel proportional valve controller based on the master-slave control architecture according to claim 1, characterized in that: The programmable array logic receives external analog input and digital input commands and responds; The programmable array logic solves the corresponding driving current according to the pressure or flow command determined by the microcontroller, and adjusts the PWM duty cycle based on the current, and sends it to the multi-channel current amplification drive function module through its I / O port, and finally outputs the target current to drive the proportional valve; The programmable array logic can realize current closed-loop control, detect current deviation in real time and correct the deviation to ensure the current output accuracy.

3. The multi-channel proportional valve controller based on the master-slave control architecture according to claim 1, characterized in that: The multi-channel current amplification driving function module adopts a PWM switch-type driving MOS tube closed mode. When PWM is at a high level, the MOS tube is turned on, and a closed loop is formed. Current passes through the proportional valve and the proportional valve starts to work. When PWM is at a low level, the MOS tube is disconnected. At this time, the circuit is in an open circuit state, no current passes through the proportional valve, and the proportional valve stops working. The multi-channel current amplification drive function module directly determines the output current size according to the received PWM duty cycle size. The higher the duty cycle, the larger the output current, and the lower the duty cycle, the smaller the output current. The lower limit of the current output by the multi-channel current amplification drive function module is zero ampere, and the upper limit of the current depends on the supply voltage and loop resistance.

4. The multi-channel proportional valve controller based on the master-slave control architecture according to claim 1, characterized in that: The multi-channel current sampling functional module adopts a precision resistor + integrated current detection operational amplifier method. The precision resistor is connected in series in the current amplification drive circuit. The voltage across the precision resistor is collected and the voltage is amplified through the integrated current detection operational amplifier. The analog quantity collection signal is converted into a digital signal through the A / D analog-to-digital conversion chip and transmitted to the programmable array logic through the I / O port, so as to infer the current driving current size and perform subsequent current PI closed-loop control.

5. The multi-channel proportional valve controller based on the master-slave control architecture according to claim 1, characterized in that: The analog input function module is used to receive external analog control signals, and after passing through a conditioning circuit composed of protection devices and precision resistors, the signals are converted to an A / D analog-to-digital conversion chip and then transmitted to a programmable array logic.

6. The multi-channel proportional valve controller based on the master-slave control architecture according to claim 1, characterized in that: The digital output function module receives instructions through the I / O port of the programmable array logic and outputs the current working state of the proportional valve.

7. The multi-channel proportional valve controller based on the master-slave control architecture according to claim 1, characterized in that: The pressure and flow feedback function module is used to collect the pressure or flow feedback signal currently output by the proportional valve, and convert it into a digital quantity through the A / D analog-to-digital conversion chip, and transmit it to the microcontroller through the I / O port, and complete the pressure and flow closed-loop control inside the microcontroller to ensure the pressure and flow control accuracy of the proportional valve in real time.

8. The multi-channel proportional valve controller based on the master-slave control architecture according to claim 1, characterized in that: The multi-channel proportional valve controller also includes a data storage function module and a power supply function module; The data storage function module is used to store signal acquisition data and historical commands for controlling output; The power supply function module is powered by an external 24V power supply, which is converted into the voltage required by each electronic component through a voltage conversion chip to ensure the normal operation of each electronic component.

9. A multi-channel proportional valve control method based on the controller of claim 1, characterized in that: The steps include: 1) The user initializes, sets parameters, and sets the ramp of the microcontroller through the communication function module, and sends the pressure or flow command to the microcontroller. The microcontroller generates a pressure or flow reference value, and solves the pressure and flow control deviation at the current moment based on the pressure and flow measurement values ​​collected by the pressure and flow feedback function module, and solves the drive current target value at the next moment based on the pressure and flow closed-loop control algorithm, and transmits it to the programmable array logic through the SPI bus for bottom-level driving; 2) The programmable array logic compares the deviation between the current measurement value collected by the multi-channel current sampling function module and the current target value, and solves the PWM output duty cycle at the next moment based on the current closed-loop control algorithm; 3) The multi-channel current amplification drive function module adjusts the MOS tube opening and closing time according to the solved PWM duty cycle to adjust the output current, and further controls the pressure and flow of the proportional valve.

10. The method according to claim 9, characterized in that In step 2), the current closed-loop control algorithm adopts a current proportional-integral (PI) control method based on integrator anti-saturation. The current proportional-integral control method based on integrator anti-saturation takes into account the saturation nonlinear characteristics of the current amplification drive circuit and limits the upper and lower limits of the current controller output to u max and u min , when the current controller controls the quantity u c >u max , the controller only accumulates negative deviation values; When the current controller controls the quantity u c min , the controller only accumulates positive deviation values, thereby limiting the current controller control quantity u c Staying in the saturation zone for a long time can improve the response speed of the proportional valve.​

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