Hydraulic turntable control system and turntable control method

Abstract

This invention belongs to the field of electromechanical-hydraulic control technology based on digital bus, and discloses a hydraulic turntable control system and a turntable control method. This invention maintains high efficiency in the turntable hydraulic control system by real-time acquisition of the pressure values ​​at the inlet and outlet of the hydraulic motor and controlling the motor displacement based on the pressure difference. It employs a hot-redundancy operating mode with primary and backup dual-path hydraulic control circuits operating simultaneously online, and real-time switching control based on circuit status to improve system reliability, thus meeting the high efficiency and high reliability requirements of radar, optical equipment, and other devices on mobile platforms for hydraulically driven turntables.

Description

Technical Field

[0001] This invention relates to the field of electromechanical-hydraulic control technology based on digital bus, and in particular to a hydraulic turntable control system and a turntable control method. Background Technology

[0002] In high-precision detection and tracking equipment such as radar and optical telescopes, the turntable, as the core rotating mechanism carrying critical loads such as radar antennas and optical lenses, plays a crucial role in achieving precise horizontal rotation control. The turntable is typically driven by an electric motor, which rotates the main shaft via a reducer and gears, thus enabling flexible adjustment of the load's azimuth angle. However, in situations where a readily available hydraulic power source is available, or in environments with extremely stringent electromagnetic compatibility requirements (such as ships or areas with strong electromagnetic interference), hydraulic motors become an ideal alternative to electric motors. Hydraulic motors not only provide high torque output but also possess excellent electromagnetic interference resistance, thus finding widespread application in these special scenarios.

[0003] It is worth noting that the operating efficiency of hydraulic control systems that use hydraulic motors as the controlled object is not constant but fluctuates significantly with changes in operating conditions. On mobile platforms such as aircraft, due to strict limitations on energy carrying capacity or for comprehensive life-cycle cost control considerations, it is essential to ensure that the hydraulic control system maintains high operating efficiency under various operating conditions. Otherwise, low efficiency will directly lead to energy waste and increased heat generation, thereby affecting the platform's endurance and the continuous working performance of equipment. Meanwhile, as the reliability requirements of equipment such as radar and optical telescopes in reconnaissance, space observation, and other fields continue to increase, the technical indicators of turntables, as a key component, in terms of dynamic response, positioning accuracy, environmental adaptability, and long-term stable operation are becoming increasingly stringent. This not only places higher demands on the mechanical structure design of the turntable itself but also poses a severe challenge to the matching, energy efficiency optimization, and fault tolerance capabilities of its hydraulic drive and control system. Therefore, researching efficient, reliable, and adaptable hydraulic turntable control systems has become an important technical direction for improving overall machine performance. Summary of the Invention

[0004] This invention aims to provide a hydraulic turntable control system and method. It utilizes pressure sensors installed at the inlet and outlet of the hydraulic motor to sense operating conditions, and combines this with the coordinated control of the electro-hydraulic servo valve and the hydraulic motor displacement to maintain the hydraulic system's operating efficiency at its optimal state. Furthermore, an electromagnetic relay selects one of two simultaneously operating control circuits to connect to the control element and sensor, with the hydraulic control performed by the processor program in the current circuit. If the current circuit malfunctions, a switching circuit can control the electromagnetic relay in real time to switch to the other circuit to continue controlling the hydraulic system, ensuring the reliability of the hydraulic control system.

[0005] To achieve the above objectives, the present invention provides a hydraulic turntable control system, including a hydraulic control circuit and a switching circuit, wherein the hydraulic control circuit includes a main hydraulic control circuit and a backup hydraulic control circuit with identical structures.

[0006] The main hydraulic control circuit, the backup hydraulic control circuit, and the switching circuit are interconnected via a CAN bus. The switching circuit obtains the status information of the main hydraulic control circuit and the backup hydraulic control circuit through communication, and then connects them to the hydraulic components of each turntable through relays.

[0007] If both the main hydraulic control circuit and the backup hydraulic control circuit are fault-free, the switching circuit control relay will connect the main circuit signal to the turntable hydraulic components.

[0008] If the main hydraulic control circuit malfunctions, the switching circuit control relay will connect the backup signal to the turntable hydraulic components.

[0009] Furthermore, the main hydraulic control circuit is installed in the main slot of the hydraulic turntable control system, and the backup hydraulic control circuit is installed in the backup slot of the hydraulic turntable control system. The switching circuit automatically identifies the difference in voltage levels of the pins at the same position in the slot.

[0010] Furthermore, the hydraulic control circuit includes a processor, peripheral circuits, an electromagnetic directional valve coil on / off control circuit, a servo valve coil current control circuit, a hydraulic motor variable displacement coil current control circuit, a temperature and pressure sensor conversion circuit, and a CAN bus communication circuit.

[0011] The processor contains a control module that controls the on / off control circuit of the electromagnetic reversing valve coil to realize the connection and disconnection between the hydraulic turntable system and the external oil source.

[0012] The processor controls the direction and magnitude of the current in the servo valve coil current control circuit, which drives the hydraulic motor to achieve turntable rotation control.

[0013] The processor controls the current in the variable displacement coil current control circuit of the hydraulic motor to change the internal volume of the hydraulic motor in real time. The pressure at the inlet and outlet of the hydraulic motor is collected in real time through the temperature and pressure sensor conversion circuit, the pressure difference is calculated and the displacement control value of the hydraulic motor is determined accordingly.

[0014] Furthermore, in the electromagnetic reversing valve coil on / off control circuit, one end of the electromagnetic valve coil is connected to the positive terminal of the 24V power supply output by the control circuit, and the other end of the electromagnetic valve coil is connected to the source of the MOS switch in the control circuit via the relay contact in the switching circuit. The electromagnetic valve control input is controlled by the processor. When the input signal is high, the MOS switch is turned on, and the electromagnetic valve coil is connected to the positive and negative terminals of 24V. At the same time, the source level of the MOS switch is divided by a resistor and compared with the set threshold voltage by a comparator to output a high or low level, which is used as the switch feedback output to the processor.

[0015] Furthermore, in the servo valve coil current control circuit, the two ends of the servo valve coil are connected to the output terminal of the power operational amplifier and the operational amplifier feedback network in the control circuit through the contacts of the relay in the switching circuit, respectively. The processor inputs the D / A signal to the negative input terminal of the power operational amplifier through digital-to-analog conversion, and drives the servo valve coil through the current which is the voltage corresponding to the D / A signal divided by the resistance value of resistor R1.

[0016] At the same time, the signal at the resistor R1 terminal is input to the processor's A / D interface to collect the voltage value in real time and calculate the servo valve coil current for monitoring.

[0017] Furthermore, in the hydraulic motor variable displacement coil current control circuit, one end of the variable displacement coil is connected to the positive terminal of the 24V power supply of the control circuit through the current sampling resistor R2, and the other end of the coil is connected to the source of the MOSFET through the relay contact in the switching circuit. The gate of the MOSFET is driven by the PWM signal output by the processor PWM interface. The duty cycle of the PWM signal corresponds to the length of time the 24V voltage is applied to the coil.

[0018] The voltage across the current sampling resistor R2 is converted by a high common-mode voltage operational amplifier and input to the processor's A / D interface. After sampling, it is used as a feedback value to participate in the coil closed-loop calculation and control the PWM signal output.

[0019] Furthermore, the switching circuit includes a processor, peripheral circuits, relay control circuits, and CAN bus communication circuits;

[0020] The processor contains a control module. The processor operates the control module through the power supply, reset, and level conversion functions of the peripheral circuit. It achieves three-way communication with the processor of the main hydraulic control circuit and the backup hydraulic control circuit via the CAN bus. The control module in the processor determines whether there is a fault in the main hydraulic control circuit and the backup hydraulic control circuit based on the status of the respective electromagnetic directional valve coil on / off control circuit, servo valve coil current control circuit, hydraulic motor variable displacement coil current control circuit, and temperature and pressure sensor conversion circuit fed back by the processor in the main hydraulic control circuit and the backup hydraulic control circuit from the CAN bus.

[0021] If both the main hydraulic control circuit and the backup hydraulic control circuit are fault-free, the switching circuit control relay will connect the main circuit signal to the turntable hydraulic components.

[0022] If the main hydraulic control circuit malfunctions, the switching circuit control relay will connect the backup signal to the turntable hydraulic components.

[0023] Furthermore, the relay control circuit includes three relays, wherein the first relay is used to switch the solenoid directional valve switch control signal and the variable displacement coil control signal, the second relay is used to switch the servo valve control signal, and the third relay is used to switch the motor pressure feedback signal.

[0024] The normally closed contact of the relay is connected to the main hydraulic control circuit signal, and the normally open contact is connected to the backup hydraulic control circuit signal.

[0025] The present invention also provides a turntable control method for a hydraulic turntable control system, comprising the following steps:

[0026] Step 1: Calculate the current speed command in real time based on the turntable speed and acceleration setpoints;

[0027] Step 2: Combine speed feedback to form a speed closed-loop proportional-integral control algorithm to obtain the servo valve coil current control command and operate the D / A interface output;

[0028] Step 3: If the servo valve output current is less than 20% of the rated value, the variable displacement coil current is controlled to 0, the hydraulic motor displacement is at its maximum, and the process ends.

[0029] Step 4: If the servo valve output current is greater than or equal to 20% of the rated value, then collect the pressure difference between the two ends of the hydraulic motor.

[0030] If the magnitude of the hydraulic motor pressure difference is less than 70% of the maximum allowable pressure difference of the system, the variable displacement coil current control value is increased by the set step amount, and the maximum output value of the servo valve is limited based on the pressure difference feedback value.

[0031] If the pressure difference of the hydraulic motor is greater than 90% of the maximum allowable pressure difference of the system, the current control value of the variable displacement coil will be reduced by the set step amount. The minimum value is the starting value, which is the current value corresponding to the start of the change in the volume of the hydraulic motor.

[0032] Beneficial Effects: This invention provides a hydraulic turntable control system and a turntable control method. Compared with the prior art, this invention has the following advantages: (1) Based on the feedback of the pressure difference between the inlet and outlet of the hydraulic motor, the displacement of the hydraulic motor is controlled in real time to adapt to the change of motor load, so that the pressure difference between the inlet and outlet of the hydraulic motor is always within a reasonable range, thereby ensuring the operating efficiency of the hydraulic system and reducing heat consumption. (2) Through the dual-path thermal redundancy of the main and backup control circuits, combined with the switching circuit through the electromagnetic relay contact switching method, the channel switching from the control circuit to the hydraulic control and feedback elements of the turntable is realized in real time, which greatly improves the task reliability of the hydraulic turntable system. (3) Through the main and backup switching control, the cause of the fault can be identified online in real time, the fault point can be accurately located, and the testing performance of the entire hydraulic turntable control system can be significantly improved. Attached Figure Description

[0033] Figure 1 This is a block diagram illustrating the principle of the hydraulic control system according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram illustrating the installation position identification principle of the main and backup hydraulic control circuits in an embodiment of the present invention.

[0035] Figure 3 This is a block diagram of the hydraulic control circuit according to an embodiment of the present invention;

[0036] Figure 4 This is a block diagram of the switching circuit involved in an embodiment of the present invention;

[0037] Figure 5 This is a circuit diagram of the on / off control of the electromagnetic directional valve according to an embodiment of the present invention;

[0038] Figure 6 This is a circuit diagram of the servo valve coil control according to an embodiment of the present invention;

[0039] Figure 7 This is a circuit diagram of a variable displacement coil control circuit according to an embodiment of the present invention;

[0040] Figure 8 This is a schematic diagram of the switching circuit electromagnetic relay involved in an embodiment of the present invention;

[0041] Figure 9 This is a flowchart of the servo valve and variable displacement control software involved in the embodiments of the present invention;

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Main hydraulic control circuit; 2. Backup hydraulic control circuit; 3. Switching circuit; 4. CAN bus; 5. Processor; 6. Peripheral circuit; 7. Electromagnetic directional valve coil on / off control circuit; 8. Servo valve coil current control circuit; 9. Hydraulic motor variable displacement coil current control circuit; 10. Temperature and pressure sensor conversion circuit; 11. CAN bus communication circuit; 12. Relay control circuit; 3. MOS switch; 14. Comparator; 15. Power operational amplifier; 16. MOS transistor; 17. High common-mode voltage resistant operational amplifier. Detailed Implementation

[0044] like Figures 1-9 As shown, the present invention provides a hydraulic turntable control system and a turntable control method. Figure 1 This is a block diagram illustrating the principle of the hydraulic control system according to an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the installation position identification principle of the main and backup hydraulic control circuits in an embodiment of the present invention. Figure 3 This is a block diagram of the hydraulic control circuit according to an embodiment of the present invention; Figure 4 This is a block diagram of the switching circuit involved in an embodiment of the present invention; Figure 5This is a circuit diagram of the on / off control of the electromagnetic directional valve according to an embodiment of the present invention; Figure 6 This is a circuit diagram of the servo valve coil control according to an embodiment of the present invention; Figure 7 This is a circuit diagram of a variable displacement coil control circuit according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the switching circuit electromagnetic relay involved in an embodiment of the present invention; Figure 9 This is a flowchart of the servo valve and variable displacement control software involved in the embodiments of the present invention.

[0045] Example 1: This embodiment of the invention provides a hydraulic turntable control system, such as... Figure 1 As shown, it includes a hydraulic control circuit and a switching circuit (3). The hydraulic control circuit includes a main hydraulic control circuit (1) and a backup hydraulic control circuit (2) with the same structure. The same structure means that the hardware and software modules are completely identical and can be directly interchanged without any settings.

[0046] The main hydraulic control circuit (1), the backup hydraulic control circuit (2) and the switching circuit (3) are interconnected through the CAN bus (4). The switching circuit (3) obtains the status information of the main hydraulic control circuit (1) and the backup hydraulic control circuit (2) through communication, and then connects them to each turntable hydraulic component after passing through a relay.

[0047] If both the main hydraulic control circuit (1) and the backup hydraulic control circuit (2) are fault-free, the switching circuit (3) controls the relay to connect the main circuit signal to the turntable hydraulic components.

[0048] If the main hydraulic control circuit (1) malfunctions, the switching circuit (3) controls the relay to connect the backup signal to the turntable hydraulic components.

[0049] like Figure 2 As shown, the main hydraulic control circuit (1) is installed in the main slot of the hydraulic turntable control system, and the backup hydraulic control circuit (2) is installed in the backup slot of the hydraulic turntable control system. The switching circuit (3) automatically identifies the different voltage levels of the pins at the same position in the slot.

[0050] like Figure 3 As shown, the hydraulic control circuit includes a processor (5), peripheral circuits (6), electromagnetic reversing valve coil on / off control circuit (7), servo valve coil current control circuit (8), hydraulic motor variable displacement coil current control circuit (9), temperature and pressure sensor conversion circuit (10), and CAN bus communication circuit (11).

[0051] The processor (5) is equipped with a control module. The processor (5) controls the on / off control circuit (7) of the electromagnetic reversing valve coil to realize the on / off connection between the hydraulic turntable system and the external oil source.

[0052] The processor (5) controls the direction and magnitude of the current in the servo valve coil current control circuit (8) to drive the hydraulic motor to achieve turntable rotation control;

[0053] The processor (5) controls the current in the hydraulic motor variable displacement coil current control circuit (9) to change the internal volume of the hydraulic motor in real time. The pressure at the inlet and outlet of the hydraulic motor is collected in real time through the temperature and pressure sensor conversion circuit (10), the pressure difference is calculated and the hydraulic motor displacement control value is determined accordingly.

[0054] like Figure 5 As shown, in the electromagnetic reversing valve coil on / off control circuit (7), one end of the electromagnetic valve coil is connected to the positive terminal of the 24V power supply output by the control circuit, and the other end of the electromagnetic valve coil is connected to the source of the MOS switch (13) in the control circuit through the relay contact in the switching circuit. The electromagnetic valve control input is controlled by the processor (5). When the input signal is high level, the MOS switch (13) is turned on, and the electromagnetic valve coil is connected to the positive and negative terminals of 24V. At the same time, the source level of the MOS switch (13) is divided by a resistor and compared with the set threshold voltage by a comparator to output a high or low level, which is used as a switch feedback output to the processor.

[0055] like Figure 6 As shown, in the servo valve coil current control circuit (8), the two ends of the servo valve coil are connected to the output terminal of the power operational amplifier (15) and the operational amplifier feedback network in the control circuit via the contacts of the relay in the switching circuit (3). The processor (5) inputs the D / A signal to the negative input terminal of the power operational amplifier (15) through digital-to-analog conversion, and drives the servo valve coil through the current obtained by dividing the voltage corresponding to the D / A signal by the resistance value of resistor R1.

[0056] At the same time, the signal at the resistor R1 terminal is input to the processor's A / D interface to collect the voltage value in real time and calculate the servo valve coil current for monitoring.

[0057] like Figure 7 As shown, in the hydraulic motor variable displacement coil current control circuit (9), one end of the variable displacement coil is connected to the positive terminal of the 24V power supply of the control circuit through the current sampling resistor R2, and the other end of the coil is connected to the source of the MOS transistor (16) through the relay contact in the switching circuit (3). The gate of the MOS transistor is driven by the PWM signal output by the processor PWM interface. The duty cycle of the PWM signal corresponds to the length of time the 24V voltage is applied to the coil.

[0058] The voltage across the current sampling resistor R2 is converted by the high common-mode voltage operational amplifier (17) and input to the processor A / D interface. After sampling, it is used as a feedback value to participate in the coil closed-loop calculation and control the PWM signal output.

[0059] like Figure 4As shown, the switching circuit includes a processor, peripheral circuits, a relay control circuit, and a CAN bus communication circuit; the relay control circuit includes relays, and the CAN bus communication circuit includes a CAN bus.

[0060] The processor contains a control module. The processor operates the control module through the power supply, reset, and level conversion functions of the peripheral circuit. It achieves three-way communication with the processor of the main hydraulic control circuit and the backup hydraulic control circuit via the CAN bus. The control module in the processor determines whether there is a fault in the main hydraulic control circuit and the backup hydraulic control circuit based on the status of the respective electromagnetic directional valve coil on / off control circuit, servo valve coil current control circuit, hydraulic motor variable displacement coil current control circuit, and temperature and pressure sensor conversion circuit fed back by the processor in the main hydraulic control circuit and the backup hydraulic control circuit from the CAN bus.

[0061] If both the main hydraulic control circuit and the backup hydraulic control circuit are fault-free, the switching circuit control relay will connect the main circuit signal to the turntable hydraulic components.

[0062] If the main hydraulic control circuit malfunctions, the switching circuit control relay will connect the backup signal to the turntable hydraulic components.

[0063] like Figure 8 As shown, the relay control circuit includes three relays. The first relay is used to switch the solenoid directional valve switch control signal and the variable displacement coil control signal. The second relay is used to switch the servo valve control signal. The third relay is used to switch the motor pressure feedback signal.

[0064] The normally closed contact of the relay is connected to the main hydraulic control circuit signal, and the normally open contact is connected to the backup hydraulic control circuit signal.

[0065] Example 2: The present invention also provides a turntable control method for a hydraulic turntable control system, such as... Figure 9 As shown, it includes the following steps:

[0066] Step 1: Calculate the current speed command in real time based on the turntable speed and acceleration setpoints;

[0067] Step 2: Combine speed feedback to form a speed closed-loop proportional-integral control algorithm to obtain the servo valve coil current control command and operate the D / A interface output;

[0068] Step 3: If the servo valve output current is less than 20% of the rated value, the variable displacement coil current is controlled to 0, the hydraulic motor displacement is at its maximum, and the process ends.

[0069] Step 4: If the servo valve output current is greater than or equal to 20% of the rated value, then collect the pressure difference between the two ends of the hydraulic motor.

[0070] If the magnitude of the hydraulic motor pressure difference is less than 70% of the maximum allowable pressure difference of the system, the variable displacement coil current control value is increased by the set step amount, and the maximum output value of the servo valve is limited based on the pressure difference feedback value.

[0071] If the pressure difference of the hydraulic motor is greater than 90% of the maximum allowable pressure difference of the system, the current control value of the variable displacement coil will be reduced by the set step amount. The minimum value is the starting value, which is the current value corresponding to the start of the change in the volume of the hydraulic motor.

[0072] This invention provides a hydraulic turntable control system and a turntable control method. By collecting the pressure values ​​at the inlet and outlet of the hydraulic motor in real time and controlling the motor displacement based on the pressure difference, the hydraulic control system of the turntable maintains high efficiency. It adopts a hot redundancy working mode with main and backup hydraulic control circuits running online simultaneously and switching control in real time according to the circuit status to improve the system's task reliability, thus meeting the high efficiency and high reliability requirements of radar, optical equipment and other devices on mobile platforms for hydraulically driven turntables.

[0073] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulic turntable control system, characterized in that, It includes a hydraulic control circuit and a switching circuit, wherein the hydraulic control circuit includes a main hydraulic control circuit and a backup hydraulic control circuit with the same structure; The main hydraulic control circuit, the backup hydraulic control circuit, and the switching circuit are interconnected via a CAN bus. The switching circuit obtains the status information of the main hydraulic control circuit and the backup hydraulic control circuit through communication, and then connects them to the hydraulic components of each turntable through relays. If both the main hydraulic control circuit and the backup hydraulic control circuit are fault-free, the switching circuit control relay will connect the main circuit signal to the turntable hydraulic components. If the main hydraulic control circuit malfunctions, the switching circuit control relay will connect the backup signal to the turntable hydraulic components.

2. The hydraulic turntable control system according to claim 1, characterized in that, The main hydraulic control circuit is installed in the main slot of the hydraulic turntable control system, and the backup hydraulic control circuit is installed in the backup slot of the hydraulic turntable control system. The switching circuit automatically identifies the different voltage levels of the pins at the same position in the slot.

3. The hydraulic rotary table control system according to claim 1, characterized in that, The hydraulic control circuit includes a processor, peripheral circuits, an on / off control circuit for the solenoid directional valve coil, a current control circuit for the servo valve coil, a current control circuit for the hydraulic motor variable displacement coil, a temperature and pressure sensor conversion circuit, and a CAN bus communication circuit. The processor contains a control module that controls the on / off control circuit of the electromagnetic reversing valve coil to realize the connection and disconnection between the hydraulic turntable system and the external oil source. The processor controls the direction and magnitude of the current in the servo valve coil current control circuit, which drives the hydraulic motor to achieve turntable rotation control. The processor controls the current in the variable displacement coil current control circuit of the hydraulic motor to change the internal volume of the hydraulic motor in real time. The pressure at the inlet and outlet of the hydraulic motor is collected in real time through the temperature and pressure sensor conversion circuit, the pressure difference is calculated and the displacement control value of the hydraulic motor is determined accordingly.

4. The hydraulic rotary table control system according to claim 3, characterized in that, In the electromagnetic reversing valve coil on / off control circuit, one end of the electromagnetic valve coil is connected to the positive terminal of the 24V power supply output by the control circuit, and the other end of the electromagnetic valve coil is connected to the source of the MOS switch in the control circuit through the relay contact in the switching circuit. The electromagnetic valve control input is controlled by the processor. When the input signal is high, the MOS switch is turned on, and the electromagnetic valve coil is connected to the positive and negative terminals of 24V. At the same time, the source level of the MOS switch is divided by a resistor and compared with the set threshold voltage by a comparator to output a high or low level, which is used as the switch feedback output to the processor.

5. The hydraulic rotary table control system according to claim 3, characterized in that, In the servo valve coil current control circuit, the two ends of the servo valve coil are connected to the output terminal of the power operational amplifier and the operational amplifier feedback network in the control circuit through the contacts of the relay in the switching circuit. The processor inputs the D / A signal to the negative input terminal of the power operational amplifier through digital-to-analog conversion, and drives the servo valve coil through the current which is the voltage corresponding to the D / A signal divided by the resistance value of resistor R1. At the same time, the signal at the resistor R1 terminal is input to the processor's A / D interface to collect the voltage value in real time and calculate the servo valve coil current for monitoring.

6. The hydraulic rotary table control system according to claim 3, characterized in that, In the hydraulic motor variable displacement coil current control circuit, one end of the variable displacement coil is connected to the positive terminal of the 24V power supply of the control circuit through the current sampling resistor R2, and the other end of the coil is connected to the source of the MOSFET through the relay contact in the switching circuit. The gate of the MOSFET is driven by the PWM signal output by the processor PWM interface. The duty cycle of the PWM signal corresponds to the length of time that the 24V voltage is applied to the coil. The voltage across the current sampling resistor R2 is converted by a high common-mode voltage operational amplifier and input to the processor's A / D interface. After sampling, it is used as a feedback value to participate in the coil closed-loop calculation and control the PWM signal output.

7. The hydraulic rotary table control system according to claim 1, characterized in that, The switching circuit includes a processor, peripheral circuits, relay control circuits, and a CAN bus communication circuit. The processor contains a control module. The processor operates the control module through the power supply, reset, and level conversion functions of the peripheral circuit. It achieves three-way communication with the processor of the main hydraulic control circuit and the backup hydraulic control circuit via the CAN bus. The control module in the processor determines whether there is a fault in the main hydraulic control circuit and the backup hydraulic control circuit based on the status of the respective electromagnetic directional valve coil on / off control circuit, servo valve coil current control circuit, hydraulic motor variable displacement coil current control circuit, and temperature and pressure sensor conversion circuit fed back by the processor in the main hydraulic control circuit and the backup hydraulic control circuit from the CAN bus. If both the main hydraulic control circuit and the backup hydraulic control circuit are fault-free, the switching circuit control relay will connect the main circuit signal to the turntable hydraulic components. If the main hydraulic control circuit malfunctions, the switching circuit control relay will connect the backup signal to the turntable hydraulic components.

8. The hydraulic rotary table control system according to claim 7, characterized in that, The relay control circuit includes three relays: the first relay is used to switch the solenoid directional valve switch control signal and the variable displacement coil control signal; the second relay is used to switch the servo valve control signal; and the third relay is used to switch the motor pressure feedback signal. The normally closed contact of the relay is connected to the main hydraulic control circuit signal, and the normally open contact is connected to the backup hydraulic control circuit signal.

9. A turntable control method for a hydraulic turntable control system, characterized in that, Includes the following steps: Step 1: Calculate the current speed command in real time based on the turntable speed and acceleration setpoints; Step 2: Combine speed feedback to form a speed closed-loop proportional-integral control algorithm to obtain the servo valve coil current control command and operate the D / A interface output; Step 3: If the servo valve output current is less than 20% of the rated value, the variable displacement coil current is controlled to 0, the hydraulic motor displacement is at its maximum, and the process ends. Step 4: If the servo valve output current is greater than or equal to 20% of the rated value, then collect the pressure difference between the two ends of the hydraulic motor. If the magnitude of the hydraulic motor pressure difference is less than 70% of the maximum allowable pressure difference of the system, the variable displacement coil current control value is increased by the set step amount, and the maximum output value of the servo valve is limited based on the pressure difference feedback value. If the pressure difference of the hydraulic motor is greater than 90% of the maximum allowable pressure difference of the system, the current control value of the variable displacement coil will be reduced by the set step amount. The minimum value is the starting value, which is the current value corresponding to the start of the change in the volume of the hydraulic motor.

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