An integrated pitch controller for a variable pitch propeller based on analog circuitry

Abstract

The application discloses a pitch control device for a pitch control system of a propeller, and belongs to the technical field of electro-hydraulic servo control.The pitch control device comprises a power supply circuit, a pitch control circuit and a system alarm circuit.The power supply circuit provides stable power supply for each sub-circuit.The pitch control circuit comprises a pitch command signal conditioning unit, a pitch feedback signal conditioning unit, a PI parameter adjustment unit and a proportional valve driving and amplifying unit, and can condition the command signal of a telegraph handle, collect and calibrate the pitch feedback signal in real time, and realize accurate closed-loop control through proportional and integral adjustment.The proportional valve driving circuit controls the forward and reverse proportional valve coils respectively, and ensures the accurate action of the pitch control system.The system alarm circuit is responsible for monitoring and providing alarm and protection when a fault occurs, and ensures the safe and stable operation of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electro-hydraulic servo control, in particular to a pitch control integrated controller for a variable-pitch propeller based on analog circuit. BACKGROUND

[0002] At present, the pitch control of a variable-pitch propeller in China is mainly a digital control system with a general PLC as a core controller. Most of the PLCs are imported products, and the most commonly used PLCs are the Siemens series PLCs. Meanwhile, the proportional valve driving amplification board and the pitch feedback circuit used with the pitch controller of the variable-pitch propeller are independent of the controller and are used jointly with the pitch follow-up control. In order to reduce the development cost, a special pitch control integrated controller for a variable-pitch propeller is developed, which is low in price, powerful in function, stable in performance, and integrates the pitch feedback and the proportional valve driving circuit. The development of the pitch control integrated controller for a variable-pitch propeller based on analog electronic components and analog control circuit is also a relatively practical scheme. SUMMARY

[0003] The purpose of the present application is to provide a replaceable, low-cost and stable performance scheme for the self-development of the pitch controller of a variable-pitch propeller by using mature and stable analog circuit and analog electronic components.

[0004] The technical scheme of the present application is to provide a pitch control integrated controller for a variable-pitch propeller based on analog circuit, which comprises a power supply circuit, a pitch control circuit and a system alarm circuit.

[0005] The power supply circuit converges the external power supply to supply power to the pitch control circuit and the alarm circuit.

[0006] The pitch control circuit comprises a pitch command signal conditioning circuit, a pitch feedback signal conditioning circuit, a PI parameter adjustment circuit and a proportional valve driving amplification circuit.

[0007] The pitch instruction signal conditioning circuit receives and conditions the pitch instruction current or voltage signal sent by the engine telegraph handle, ensures that the engine telegraph handle outputs zero voltage when the handle is at zero position, and outputs corresponding voltage signals when the handle is at maximum forward or reverse position; the pitch feedback signal conditioning circuit collects the feedback signal of the pitch adjusting propeller, performs real-time voltage tracking and calibration on the pitch feedback signal through reverse amplification and addition circuit, independently adjusts the feedback signals of the forward and reverse pitch, and ensures that the signal change matches the actual mechanical displacement; the PI parameter adjustment circuit receives the instruction signal and the feedback signal, combines the inputs through filtering and addition circuit, adjusts the proportional and integral parameters of the forward and reverse pitch respectively, and outputs the pitch adjusting control signal; the proportional valve driving amplification circuit controls the proportional valve through PID adjustment, drives the corresponding proportional valve coil in the forward and reverse two paths, and controls the forward and reverse movement of the pitch adjusting propeller.

[0008] The system alarm circuit monitors the system operation state and provides alarm and protection functions when a fault occurs.

[0009] In any of the above technical solutions, further, the power supply circuit includes a power supply bus circuit and a voltage stabilizing and isolating circuit; the power supply bus circuit connects two external power supplies into one power supply circuit through diodes, and the two external power supplies are used as backup for each other; the power supply after bus connection is divided into two paths, one of which is used to supply power to the proportional valve driving amplification circuit, and the other of which is used to supply power to the pitch adjusting control circuit and the system alarm circuit through the voltage stabilizing and isolating circuit.

[0010] In any of the above technical solutions, further, the pitch instruction signal conditioning circuit includes a pitch instruction signal selection circuit, a zero position and range adjustment circuit, and a signal delay and current limiting circuit.

[0011] The pitch instruction signal selection circuit receives the pitch instruction signal sent by the external engine telegraph handle, the signal can be in the form of current or voltage, and the current / voltage selection circuit is used to convert the signal into a pitch instruction voltage signal;

[0012] The zero position and range adjustment circuit performs reverse amplification on the signal through a reverse proportional amplification circuit, generates a negative voltage signal, and adds the negative voltage signal to the positive voltage output by the potentiometer through an addition circuit, so as to adjust the zero position, forward position and reverse position of the handle, so that the engine telegraph handle outputs zero voltage signal when the handle is at zero position, and outputs positive or negative voltage signal when the handle is at maximum forward or reverse position;

[0013] The signal delay and current limiting circuit delays the rapid change of the handle position through a diode positive and negative connection circuit and a reverse integral amplification circuit, prevents the sudden change of the instruction signal from causing sudden change of the pitch, thereby reducing the sudden increase and decrease of the main engine load, and limits the maximum voltage input of the signal through a voltage stabilizing diode.

[0014] Further, the screw pitch feedback signal conditioning circuit comprises a screw pitch feedback acquisition circuit and a screw pitch zero position and forward / reverse range independent adjustment circuit.

[0015] The screw pitch feedback acquisition circuit provides a reference voltage signal to a potentiometer in the screw pitch feedback mechanism of the pitch control propeller and acquires the feedback signal output by the potentiometer, and the feedback signal is amplified in real time by a reverse proportional amplification circuit.

[0016] The feedback signal is calibrated to zero voltage by the screw pitch zero position and forward / reverse range independent adjustment circuit, so that the screw pitch feedback signal outputs a zero voltage signal when the screw pitch mechanical pointer is at zero thrust.

[0017] When the screw pitch is at the maximum forward or reverse position, the feedback signal enters the independent amplification circuit with a forward / reverse diode, and the feedback signal of the screw pitch at the forward or reverse position is independently adjusted in voltage range by adjusting the potentiometer, to ensure that the screw pitch feedback signal can accurately reflect the change of the pitch control propeller screw pitch in the full range.

[0018] Further, the PI parameter adjustment circuit receives the screw pitch command signal and the screw pitch feedback signal after signal conditioning, and inputs the combined signal into the PI adjustment module through the addition circuit and the filter circuit.

[0019] The PI parameter adjustment circuit comprises a proportional amplification circuit and an integral circuit, which adjusts the proportional parameter through the potentiometer P13, adjusts the integral parameters of forward and reverse through the potentiometers P7 and P8, respectively, and controls the screw pitch differently during forward and reverse adjustment; the signal after proportional amplification and integration processing generates a screw pitch control signal VOUT1, which is output to the proportional valve drive amplification circuit for power amplification and proportional valve control.

[0020] Further, the proportional valve drive amplification circuit is composed of a proportional valve PID adjustment circuit, a forward / reverse power amplification circuit and a forward / reverse chattering circuit.

[0021] The proportional valve PID adjustment circuit receives the screw pitch control signal VOUT1 output by the PI parameter adjustment circuit, adjusts the proportional, integral and differential parameters of the proportional valve control through the proportional valve PID adjustment circuit, adjusts the proportional parameter through the potentiometer P19, adjusts the integral parameter through P20, and adjusts the differential parameter through P21.

[0022] The screw pitch control signal after proportional valve PID adjustment circuit adjustment enters the forward / reverse power amplification circuit, generates forward and reverse control signals, respectively, and is combined with the chattering signal, and the A coil or B coil of the proportional valve is driven through the power amplification circuit to control the action of the proportional electromagnetic valve, realizing the movement of the pitch control propeller to the forward or reverse direction.

[0023] In any of the above technical solutions, further, the controller further comprises an unloading valve control output circuit, which receives a pitch control signal output by the PI adjusting circuit, and when the pitch control reaches a predetermined position, drives a transistor through a reverse proportional amplification circuit to make a relay powered, and an output signal makes the unloading valve act, and the hydraulic system enters an unloading state, and when the pitch needs to be adjusted again, the transistor driving circuit makes the relay lose power, the relay outputs a working signal to the unloading valve, the unloading valve is powered again to be closed, and the hydraulic system establishes pressure and resumes work.

[0024] In any of the above technical solutions, further, the system alarm circuit has multiple alarm functions, including an alarm reset circuit, an alarm output and pitch locking circuit, an instruction signal and pitch signal deviation alarm circuit, an instruction signal out-of-range alarm circuit, a feedback signal out-of-range alarm circuit and a power failure alarm circuit.

[0025] The alarm reset circuit is used to clear the alarm signal and re-enter the monitoring state by manually pressing the reset button when the alarm occurs; the alarm output and pitch locking circuit disconnects the proportional valve control signal when the alarm occurs to lock the pitch and prevent the pitch from being continuously adjusted; the instruction signal and pitch signal deviation alarm circuit is used to detect the deviation between the instruction signal and the pitch feedback signal, and when the deviation exceeds a preset threshold, the alarm is triggered and the pitch is locked; the instruction signal out-of-range alarm circuit triggers the alarm when the maximum and minimum values of the instruction signal exceed the preset range; the feedback signal out-of-range alarm circuit is used to monitor whether the feedback signal exceeds the set maximum and minimum values, and triggers the alarm and locks the pitch when the range is exceeded; and the power failure alarm circuit is used to detect the power voltage, and triggers the alarm and locks the pitch when the power voltage is lower than the preset value.

[0026] The beneficial effects of the present application are:

[0027] The technical solution in the present application has all basic functions required for pitch control of various types of ship controllable pitch propellers, and can replace the controllable pitch propeller ships using imported pitch controllers; the present application uses very mature and high reliability analog control circuit technology, adopts stable performance analog electronic components and simple and reliable integrated circuits, and realizes all basic functions required for integrated pitch controller of controllable pitch propeller, such as signal conditioning, PID closed-loop automatic control, fault alarm, alarm protection, etc. At the same time, the controller integrates pitch feedback signal acquisition, unloading valve output control and proportional valve driving amplification functions, realizes all functional links required for controllable pitch propeller pitch closed-loop control system on one controller, reduces the intermediate links of the closed-loop control system, reduces the failure rate of the controllable pitch propeller pitch control system, and facilitates the later maintenance, maintenance and maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and additional aspects of the present application will become apparent and readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1 is a whole structure flow chart of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0030] Figure 2 is a power supply circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0031] Figure 3 is a signal selection circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0032] Figure 4 is a full stroke range adjustment circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0033] Figure 5 is a delay current limiting circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0034] Figure 6 is a pitch feedback acquisition circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0035] Figure 7 is a pitch zero position and forward / reverse range independent adjustment circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0036] Figure 8 is a pitch control PI parameter adjustment circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0037] Figure 9 is a proportional valve PID adjustment circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0038] Figure 10 is a forward / reverse separation circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0039] Figure 11 is a chattering circuit schematic diagram of the analog circuit-based integrated pitch controller of the adjustable pitch propeller according to an embodiment of the present application;

[0040] Figure 12This is a schematic diagram of a power amplifier circuit for an integrated pitch controller for a pitch control propeller based on analog circuitry, according to an embodiment of the present invention.

[0041] Figure 13 This is a schematic diagram of the unloading valve control output circuit of an integrated pitch controller for a pitch control propeller based on analog circuits according to an embodiment of the present invention.

[0042] Figure 14 A schematic diagram of the alarm output and pitch locking circuit of an integrated pitch controller for a pitch control propeller based on analog circuit according to an embodiment of the present invention.

[0043] Figure 15 A schematic diagram of an alarm circuit for an integrated pitch controller for a pitch control propeller with error and pitch non-tracking according to an embodiment of the present invention.

[0044] Figure 16 A schematic diagram of an out-of-range alarm circuit for a controllable pitch propeller integrated pitch controller based on analog circuitry, according to an embodiment of the present invention.

[0045] Figure 17 A schematic diagram of a power fault alarm circuit for an integrated pitch controller for a pitch control propeller based on analog circuitry, according to an embodiment of the present invention.

[0046] Figure 18 A schematic diagram of an alarm reset circuit for an integrated pitch controller for a pitch control propeller based on analog circuitry, according to an embodiment of the present invention. Detailed Implementation

[0047] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0048] In the following description, many specific details are set forth in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0049] like Figure 1 As shown, this embodiment provides an integrated pitch controller for a pitch control propeller based on analog circuits. The controller includes a power supply circuit, a pitch control circuit, and a system alarm circuit.

[0050] The introduction and uses of each circuit include:

[0051] The power supply circuit includes a power supply confluence circuit and a voltage stabilizing and isolating circuit. Two power supplies are provided externally, combined into one through the power supply confluence circuit, and used to supply power to the subsequent proportional valve driving amplification circuit and the pitch control circuit. The voltage stabilizing and isolating circuit ensures the stability and isolation of the power supply, avoiding external interference.

[0052] The pitch control circuit includes a pitch instruction signal conditioning circuit, a pitch feedback signal conditioning circuit, a PI parameter adjusting circuit and a proportional valve driving amplification circuit.

[0053] The pitch instruction signal conditioning circuit is used to receive and condition the pitch instruction current or voltage signal sent by the engine telegraph handle. Through the reverse proportional amplification circuit of the voltage signal, it is ensured that the engine telegraph handle is zero voltage when the handle is at zero position, and the handle outputs corresponding voltage signals when the handle is at the maximum ahead or astern position.

[0054] The pitch feedback signal conditioning circuit collects the feedback signal of the pitch control, realizes real-time voltage tracking and calibration of the pitch feedback signal through the reverse amplification and addition circuit, and ensures the matching of signal change and actual mechanical displacement by independently adjusting the feedback signals of the ahead and astern pitch.

[0055] The PI parameter adjusting circuit receives the instruction signal and the feedback signal, combines the inputs through the filtering and addition circuit, and can adjust the proportional and integral parameters of the ahead control or the astern control, respectively, to output the pitch control signal.

[0056] The proportional valve driving amplification circuit realizes the control of the proportional valve through PID adjustment, and is divided into two paths of ahead and astern, respectively driving the corresponding proportional valve coil to control the ahead and astern movement of the pitch control.

[0057] The system alarm circuit includes an alarm reset circuit, an alarm output and pitch locking circuit, and provides various alarm protection functions, such as instruction signal and pitch signal mismatch alarm, instruction out-of-range alarm, feedback out-of-range alarm, etc. When the alarm occurs, the controller automatically locks the pitch to prevent serious system failure.

[0058] The specific implementation methods of each part are described in detail as follows. First, as shown in FIG. 1, the system includes a power supply circuit, a pitch control circuit, a proportional valve driving amplification circuit, a system alarm circuit and a communication interface circuit. Figure 2As shown, the power supply circuit as the power base part of the whole controller, through the power supply bus circuit and power supply isolation circuit to complete the power supply and voltage stabilization work, the controller is connected to two power supply P1 and P2, the two power supply through the diode bus circuit into a road, so that the two power supply each other standby, when one of the road failure, the other power supply can continue to work normally, to ensure the continuous operation of the system; the power supply after the convergence is divided into two, one of which is used to drive the power amplifier circuit for the proportioning valve power electronic components, the other is connected to the power supply isolation circuit for voltage isolation, power supply isolation circuit through the resistance, capacitance and power isolation module for voltage stabilization and filtering, to provide pitch control circuit and alarm circuit, at the same time, the reference power supply signal is outputted by the reference power supply module, which provides reference voltage for other sub circuit; the design of this part not only ensures the stability of the power supply, but also improves the anti-interference ability of the system through the isolation circuit.

[0059] As shown in Figures 3 to 5 , the pitch control circuit of the screw pitch instruction signal conditioning circuit is composed of screw pitch instruction signal selection circuit, full stroke range adjustment circuit, signal delay and current limiting circuit; the screw pitch instruction signal conditioning circuit receives the screw pitch instruction current or voltage signal sent by the external car bell handle, selects the current / voltage signal through the screw pitch instruction signal selection circuit, converts it into the handle screw pitch instruction voltage signal, then forms a negative voltage through the full stroke range adjustment circuit, and then performs addition operation with the positive voltage, which corrects the voltage of the car bell handle at different positions. Specifically, when the handle is at zero position, the output signal is zero voltage; when the handle is at the maximum positive or maximum reverse position, respectively through the adjustment potentiometer P4, the output signal of 10V or-10V is ensured, so that the system can accurately identify the positions of the car bell handle and convert them into corresponding voltage signals.

[0060] The instruction signal delay and current limiting circuit is the next step of the screw pitch instruction conditioning. In order to prevent the sudden change of the screw pitch caused by the rapid change of the car bell handle position, which leads to the large fluctuation of the main machine load, the delay circuit delays the signal change through the diode and the reverse integral amplifier circuit. Specifically, when the handle position changes, the signal passes through the delay circuit, and the delay time is adjusted independently for the positive and reverse signals through the potentiometers P5 and P6; in this way, when the handle is quickly switched, the signal will not be immediately transmitted to the screw pitch control system, but will be gradually adjusted in a smooth way, so as to reduce the impact on the system; in addition, the delay circuit also has a current limiting function, which limits the maximum voltage input of the instruction signal through the voltage stabilizing diode, to ensure the safe operation of the system.

[0061] As shown in Figure 6 and Figure 7As shown, the pitch feedback signal conditioning circuit of the pitch control circuit includes a pitch feedback acquisition circuit, a pitch zero and forward-reverse range independent adjustment circuit; the pitch feedback acquisition circuit acquires and conditions the feedback signal from the pitch control paddle to ensure accurate control of the pitch, the pitch feedback circuit first provides a reference voltage signal to the potentiometer installed on the pitch control paddle feedback device, and simultaneously receives the pitch feedback voltage signal output by the potentiometer. The feedback signal is processed by the reverse amplification circuit, the feedback signal is zeroed by reverse proportional amplification and addition operation, i.e. the pitch zero thrust position, the feedback signal is zero voltage, and then the independent amplification of positive and negative voltage signals is realized by the circuit with a positive and negative diode, i.e. the pitch feedback signal range when the pitch is adjusted at the maximum forward position and at the maximum reverse position, to ensure the stability and accuracy of the signal.

[0062] In the pitch zero and forward-reverse range independent adjustment circuit, the pitch feedback signal zero voltage calibration when the mechanical pointer is located at the zero thrust position is realized by adjusting the potentiometer P0; when the mechanical pointer is placed at the maximum forward or maximum reverse position, the system adjusts the potentiometers P1 and P3 through independent forward and reverse amplification circuits to individually adjust the feedback signals of the forward and reverse respectively, to ensure that the range of the feedback signal matches the actual travel of the mechanical displacement, thereby ensuring the accuracy of the closed-loop control.

[0063] As shown in Figure 8 , the processed pitch command signal and the feedback signal enter the PI parameter adjustment circuit at the same time. In the PI parameter adjustment circuit, the command signal and the feedback signal enter the reverse proportional amplification circuit after being filtered and added, where the system can adjust the proportional and integral parameters of the forward and reverse control respectively, to realize fine control in different operating modes; the proportional parameters of the forward and reverse are adjusted by the potentiometer P13, while the integral parameters are adjusted by P7 and P8 respectively; after proportional amplification and integral processing, the system generates the pitch control signal VOUT1 and outputs it to the proportional valve driving amplification circuit.

[0064] As shown in Figures 9 to 12 , the proportional valve driving amplification circuit includes a proportional valve PID circuit, a forward-reverse separation circuit, a chattering circuit and a power amplification circuit.

[0065] The proportional valve driving amplification circuit is the execution part of the whole pitch control system. After the pitch control signal generated by the PI parameter adjustment circuit enters the proportional valve PID adjustment circuit, the proportional, integral and differential parameters of the control signal are further optimized by the PID adjustment circuit. Specifically, the proportional amplification parameter is adjusted by the potentiometer P19, the integral parameter is adjusted by P20, and the differential parameter is adjusted by P21. These adjusted signals then enter the forward and reverse separation circuit to generate proportional valve forward and reverse control signals, respectively, and drive the A coil or B coil through the power amplification circuit to control the pitch to move in the forward or reverse direction.

[0066] In order to further optimize the smoothness of the pitch adjustment, the system also designs a tremor circuit to combine with the forward and reverse control signals respectively to reduce the small fluctuations in the pitch movement.

[0067] As shown in Figure 13 , the unloading valve control output circuit receives the output signal of the PI circuit, controls the conduction of the triode through reverse proportional amplification and addition operation, and makes the unloading valve powered on after the relay is powered on. The hydraulic system stops unloading and establishes working pressure. When the command and feedback error are zero, the unloading valve is de-energized and unloaded.

[0068] As shown in Figures 14 to 18 , the system alarm circuit includes alarm reset circuit, alarm output and pitch locking circuit, command signal and pitch signal deviation and pitch not following alarm protection circuit, command signal out-of-range alarm circuit, feedback signal out-of-range alarm circuit and power failure alarm circuit.

[0069] In the alarm reset circuit, the reset button SB is connected to the error and pitch not following circuit, and the alarm is eliminated by grounding the button. In the alarm output and pitch locking circuit, all alarm signals are combined and input into ALM, and the low-level signal is controlled by the triode through the comparison circuit. The relay is powered on to alarm and lock the pitch. In the command signal and pitch signal deviation and pitch not following alarm protection circuit, the feedback signal and the command signal are detected by the comparison and integration circuit to detect the error, and the alarm and pitch locking are locked when the threshold is exceeded. In the command signal out-of-range alarm circuit, when the handle command signal exceeds the set threshold, a high-level signal is output by the comparison circuit to alarm and lock the pitch. In the feedback signal out-of-range alarm circuit, when the pitch feedback signal exceeds the set threshold, a high-level signal is output by the comparison circuit to alarm and lock the pitch. In the power failure alarm circuit, when the output voltage of the power supply stable isolation power supply circuit is lower than the reference voltage, a low-level signal is output by the comparison circuit to alarm.

[0070] In conclusion, the application provides a pitch control system for a controllable pitch propeller based on analog circuit, which successfully realizes the closed-loop control and fault alarm function of the controllable pitch propeller through the cooperative work of each sub-circuit; the controller can not only accurately adjust the pitch of the controllable pitch propeller, but also ensure that the system can respond in time and take protective measures when a fault occurs through various alarm mechanisms; by using analog circuit, the application effectively reduces the development cost and improves the reliability of the system, and is especially suitable for the controllable pitch propeller control system of a ship which requires high stability and low cost.

[0071] The steps in the application can be adjusted in sequence, combined and deleted according to actual needs.

[0072] The units in the device of the application can be combined, divided and deleted according to actual needs.

[0073] Although the application has been disclosed in detail with reference to the drawings, it should be understood that the description is only exemplary and is not intended to limit the application. The scope of protection of the application is defined by the appended claims, and can include various modifications, improvements and equivalent solutions made to the application without departing from the scope and spirit of the application.

Claims

1. A pitch controller integrated for a pitch-adjustable propeller based on analog circuits, characterized in that, The controller comprises a power supply circuit, a pitch control circuit and a system alarm circuit; The power supply circuit converges external power supply sources to supply power to the pitch control circuit and the alarm circuit; The pitch control circuit comprises a pitch command signal conditioning circuit, a pitch feedback signal conditioning circuit, a PI parameter adjustment circuit and a proportional valve driving amplification circuit; The pitch command signal conditioning circuit receives and conditions the pitch command current or voltage signal from the engine telegraph handle, ensuring that the engine telegraph handle outputs zero voltage at zero position and corresponding voltage signals at maximum ahead or astern position; the pitch feedback signal conditioning circuit collects the feedback signal of the pitch control paddle, and through reverse amplification and addition circuit, performs real-time voltage tracking and calibration on the pitch feedback signal, independently adjusts the feedback signals of the ahead and astern pitch, and ensures the matching of signal change and actual mechanical displacement; the PI parameter adjustment circuit receives the command signal and the feedback signal, combines the inputs through filtering and addition circuit, adjusts the proportional and integral parameters of the ahead and astern pitch respectively, and outputs the pitch control signal; the proportional valve driving amplification circuit controls the proportional valve through PID adjustment, drives the corresponding proportional valve coil in the ahead and astern two paths respectively, and controls the ahead and astern movement of the pitch control paddle; The PI parameter adjustment circuit receives the pitch command signal and the pitch feedback signal after signal conditioning, combines the signals through addition circuit and filtering circuit, and inputs the PI adjustment module; The PI parameter adjustment circuit comprises a proportional amplification circuit and an integral circuit, which adjusts the proportional parameter through potentiometer P13, adjusts the integral parameters of the ahead and astern respectively through potentiometers P7 and P8, and controls the pitch differently in the ahead and astern adjustment process; the signal after proportional amplification and integral processing generates the pitch control signal VOUT1, which is output to the proportional valve driving amplification circuit for power amplification and proportional valve control; The system alarm circuit monitors the system operation state and provides alarm and protection functions when faults occur.

2. The analog circuit based integrated pitch control of a variable pitch propeller as claimed in claim 1, characterized in that, The power supply circuit comprises a power supply convergence circuit and a voltage stabilizing and isolating circuit; the power supply convergence circuit converges two external power supply sources into one power supply circuit through diodes, and the two external power supply sources are standby for each other; the converged power supply is divided into two paths, one of which supplies power to the proportional valve driving amplification circuit, and the other of which is stepped down through the voltage stabilizing and isolating circuit and supplies power to the pitch control circuit and the system alarm circuit.

3. The analog circuit based integrated pitch control of a variable pitch propeller as recited in claim 1, wherein, The pitch command signal conditioning circuit comprises a pitch command signal selection circuit, a zero position and range adjustment circuit, and a signal delay and current limiting circuit; The pitch command signal selection circuit receives the pitch command signal from the external engine telegraph handle, which can be in the form of current or voltage, and converts it into a pitch command voltage signal through a current / voltage selection circuit; The zero position and range adjustment circuit inversely amplifies the signal through an inverse proportional amplification circuit to generate a negative voltage signal, and adds it to the positive voltage output by the potentiometer through an addition circuit, so as to adjust the zero position, ahead and astern position of the handle, so that the engine telegraph handle outputs zero voltage signal at zero position and positive or negative voltage signal at maximum ahead or astern position; The signal delay and current limiting circuit delays the rapid change of the handle position through the forward and reverse connection circuit of diode and the reverse integral amplification circuit, prevents the sudden change of the command signal from causing the sudden change of the pitch, slows down the sudden increase and decrease of the main machine load, and limits the maximum voltage input of the signal through the voltage stabilizing diode.

4. The analog circuit based pitch control of a controllable pitch propeller integrated with a collective pitch control as defined in claim 1, characterized in that, The pitch feedback signal conditioning circuit comprises a pitch feedback acquisition circuit and a pitch zero position and forward and reverse range independent adjustment circuit. The pitch feedback acquisition circuit provides a reference voltage signal to the potentiometer in the pitch feedback mechanism of the pitch control vane, acquires the feedback signal output by the potentiometer, and amplifies the feedback signal in real time through the reverse proportional amplification circuit. The feedback signal is calibrated to zero voltage through the pitch zero position and forward and reverse range independent adjustment circuit, so that the pitch feedback signal outputs a zero voltage signal when the pitch mechanical pointer is at the zero thrust position. When the pitch is at the maximum forward or reverse position, the feedback signal enters the independent amplification circuit with the forward and reverse connection diode, and the feedback signal of the pitch at the forward or reverse position is independently adjusted in voltage range through the adjustment potentiometer, so as to ensure that the pitch feedback signal can accurately reflect the change of the pitch control vane in the full range.

5. The analog circuit based pitch control of a controllable pitch propeller integrated with a collective pitch control as defined in claim 1, characterized by The proportional valve drive amplification circuit comprises a proportional valve PID adjustment circuit, a forward and reverse power amplification circuit, and a forward and reverse tremor circuit. The proportional valve PID adjustment circuit receives the pitch control signal VOUT1 output by the PI parameter adjustment circuit, adjusts the proportional, integral and differential parameters of the proportional valve control through the proportional valve PID adjustment circuit, the proportional parameter is adjusted through the potentiometer P19, the integral parameter is adjusted through P20, and the differential parameter is adjusted through P21. The pitch control signal adjusted by the proportional valve PID adjustment circuit enters the forward and reverse power amplification circuit, generates forward and reverse control signals respectively, and is combined with the tremor signal, and then passes through the power amplification circuit to drive the A coil or B coil of the proportional valve, controls the action of the proportional electromagnetic valve, and realizes the movement of the pitch control vane to the forward or reverse direction.

6. The analog circuit based pitch control of a controllable pitch propeller integrated with a collective pitch control as defined in claim 1, characterized by The controller further comprises an unloading valve control output circuit, which receives the pitch control signal output by the PI adjustment circuit, drives the triode through the reverse proportional amplification circuit when the pitch control reaches the predetermined position, so that the relay is powered on, the output signal makes the unloading valve act, and the hydraulic system enters the unloading state. When the pitch needs to be adjusted again, the triode drive circuit makes the relay lose power, the relay outputs the working signal to the unloading valve, the unloading valve is powered on again to close, and the hydraulic system establishes pressure and restores work.

7. The analog circuit based pitch control of a controllable pitch propeller integrated with a collective pitch control as defined in claim 1, wherein, The system alarm circuit has multiple alarm functions, including alarm reset circuit, alarm output and pitch locking circuit, command signal and pitch signal deviation alarm circuit, command signal out-of-range alarm circuit, feedback signal out-of-range alarm circuit and power failure alarm circuit. The alarm reset circuit is used to clear the alarm signal and re-enter the monitoring state by manually pressing the reset button when the alarm occurs; the alarm output and pitch lock circuit disconnects the proportional valve control signal when the alarm occurs, so that the pitch is locked to prevent further adjustment of the pitch; the command signal and pitch signal deviation alarm circuit is used to detect the deviation between the command signal and the pitch feedback signal, and when the deviation exceeds the preset threshold, the alarm is triggered and the pitch is locked; the command signal out-of-range alarm circuit triggers an alarm when the maximum and minimum values of the command signal exceed the preset range; the feedback signal out-of-range alarm circuit is used to monitor whether the feedback signal exceeds the set maximum and minimum values, and triggers an alarm and locks the pitch when the range is exceeded; The power failure alarm circuit is used to detect the power voltage, and when the power voltage is lower than the preset value, the alarm is triggered and the pitch is locked.

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