A control method for avoiding swing speed of crane hoisting operation

Abstract

The application discloses a control method for avoiding turning speed of crane hoisting operation, comprising the following steps: S1, acquiring the real-time pressure P of the hydraulic pump of the crane and the real-time speed N of the engine; S2, calculating the change rate P' of the real-time pressure P of the hydraulic pump; S3, comparing the change rate P' with the first preset threshold A, if P' is greater than A, it is determined that the hydraulic pump pressure is rapidly increasing; S4, comparing the real-time pressure P of the hydraulic pump with the first pressure interval, if P is in the first gear range B1<=P<=B2, it is determined that the pump pressure is large, there is a risk of turning speed, and so on, totally including 16 steps. The application can accurately judge different dangerous levels from the risk to the imminent engine stall, effectively inhibit the initial drop of the speed, improve the diesel atomization and mixing, and effectively reduce the smoke degree.

Description

Technical Field

[0001] This invention relates to the field of crane hoisting operation technology, and in particular to a control method for preventing crane speed drops during hoisting operations. Background Technology

[0002] Cranes are widely used as indispensable engineering vehicles in fields such as construction engineering, factory transportation, and mining construction. In recent years, affected by changes in the market environment, the crane industry has faced enormous pressure to control costs. To meet market demand for low-priced cranes, OEMs have generally adopted a cost-reduction strategy of matching smaller displacement engines.

[0003] However, cranes equipped with small-displacement engines face significant challenges in lifting operations, especially under extreme conditions involving pressure buildup. In typical overload lifting, the load increases gradually during the lifting process, causing the system pressure to rise slowly. The engine control system has ample time to gradually increase fuel injection to match the load increase, thus the engine speed usually remains stable, only showing a slowdown in lifting speed without a sudden drop in speed. The real risk of insufficient power occurs when the crane reaches its mechanical limit, such as when the boom is at its highest or lowest position, the telescopic boom is fully extended or retracted, or the outriggers are at their maximum or minimum stroke. In these states, the hydraulic cylinders are completely locked, and the hydraulic oil flow path is blocked. If the operator continues to push the control handle to force oil supply at full stroke, the hydraulic system pressure will instantly surge to the maximum rated pressure set by the relief valve without buffering. This pressure surge is equivalent to an instantaneous extremely high load on the engine, easily causing a sharp drop in engine speed or even stalling due to the inability to provide timely matching power, severely affecting the safety and continuity of operations.

[0004] To address the engine speed drop caused by pressure buildup during crane lifting operations, the industry's current common approach is to have the engine control system respond reactively. Typical practices include attempting to inject fuel earlier and increasing the fuel injection volume when a speed drop is detected. However, these methods have significant limitations: the timing of earlier fuel injection is often difficult to control precisely, and injecting too early or too late will not achieve the desired effect; while simply increasing fuel injection can compensate for power to some extent, it easily leads to incomplete combustion, resulting in a sharp increase in exhaust smoke, which not only fails to meet increasingly stringent emission regulations but also worsens the working environment. Overall, existing technical solutions have limited effectiveness, failing to effectively balance engine power, response speed, and emission control while avoiding speed drop or stalling. They are ill-suited to meet the urgent needs of cranes equipped with small-displacement engines for stable, efficient, and clean operation under complex conditions.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a control method to avoid speed drops during crane hoisting operations, thereby solving the problems in the background art.

[0007] To achieve the above objectives, the present invention provides a control method for preventing the speed drop of a crane during hoisting operations, comprising the following steps:

[0008] S1: Obtain the real-time hydraulic pump pressure P and the real-time engine speed N of the crane;

[0009] S2: Calculate the rate of change P' of the real-time pressure P of the hydraulic pump;

[0010] S3: Compare the rate of change P' with the first preset threshold A. If P' is greater than A, it is determined that the hydraulic pump pressure is increasing rapidly.

[0011] S4: Compare the real-time pressure P of the hydraulic pump with the first pressure range. If P is within the first range B1≤P≤B2, it is determined that the pump pressure is too high and there is a risk of speed drop.

[0012] S5: When it is determined that the engine speed is about to drop, the PID parameters of the engine controller are corrected in real time. Specifically, this includes: superimposing a positive bias on the proportional correction coefficient ΔKp, superimposing a negative bias on the integral correction coefficient ΔKi, and superimposing a negative bias on the derivative correction coefficient ΔKd, in order to improve the controller's response speed in advance. Among them, the initial reference parameters Kp0, Ki0, and Kd0 of the PID controller are obtained based on the engine bench test calibration. The real-time corrected PID parameters are calculated by the following formula: Kp = Kp0 + ΔKp, Ki = Ki0 + ΔKi, Kd = Kd0 + ΔKd. The PID output control quantity ε corresponds to the fuel injection quantity, fuel injection pulse width, or target torque. Its calculation formula is: ε = Kp * e + Ki * ∫ e dt + Kd * de / dt, where e is the speed deviation.

[0013] S6: If the real-time pressure P of the hydraulic pump is in the second range B2 < P < B3, it is determined that the pump pressure is too high and the engine will soon face a significant drop in speed.

[0014] S7: If step S6 determines that the pump pressure is too high, increase the engine speed to the target value to increase the engine's maximum torque and power, thereby reducing the risk of speed drop.

[0015] S8: If the real-time pressure P of the hydraulic pump is in the third range, it is determined that the pump pressure is particularly high and the engine is at risk of being shut down by the pressure.

[0016] S9: Calculate the rate of decrease N' of the real-time engine speed N;

[0017] S10: Compare the descent rate N' with the limit C. If N' reaches or exceeds C, it is determined that the speed drops too fast, the hydraulic pump requires more power than the engine output power, and the engine is at risk of being shut down by the pressure.

[0018] S11: Calculate the engine speed deviation ∆N based on the difference between the real-time engine speed N and the target speed;

[0019] S12: If the speed deviation ∆N is within the first range D1≤∆N≤D2, then the engine speed is determined to have decreased slightly;

[0020] S13: If step S12 determines that the engine speed has slightly decreased, the diesel injection pressure is adjusted to increase the rail pressure, and the diesel injection time is adjusted to increase the timing, thereby improving diesel atomization, extending the mixing time, promoting complete combustion and effectively reducing smoke.

[0021] S14: Based on the effect of step S13, increase the amount of diesel fuel injected into the cylinder until the smoke level meets the standard. Increasing the amount of fuel injected can improve power output to slow down the drop in engine speed, while keeping the smoke level consistent with the original state.

[0022] S15: If the speed deviation ∆N is greater than the second threshold D2, it is determined that the engine speed has dropped to a low level and there is a risk of being stalled.

[0023] S16: If the judgment conditions of steps S8, S10 and S15 are met simultaneously, it is accurately determined that the engine is about to be shut down. The displacement of the hydraulic pump is immediately reduced to lower the pump pressure, so that the power demand of the hydraulic system is significantly lower than the power output value of the engine, thereby causing the engine speed to recover quickly and preventing the engine from shutting down.

[0024] In one embodiment of the present invention, the specific method for obtaining the real-time hydraulic pump pressure P and the real-time engine speed N of the crane in step S1 is as follows: the real-time hydraulic pump pressure P is output through the vehicle controller, and the real-time engine speed N is output through the engine controller.

[0025] In one embodiment of the present invention, step S5 generally performs a fuzzy PID adaptive correction function; the fuzzy PID adaptive correction function is based on real-time monitoring of the hydraulic pump pressure change rate P' and the current pressure gear, and biases the PID output correction value in advance before the actual decrease in engine speed occurs, actively applying a predetermined bias adjustment to the proportional, integral, and derivative coefficients of the PID controller; if a decreasing trend in speed is detected, the PID controller after bias adjustment can immediately generate a large positive deviation correction output.

[0026] In one embodiment of the present invention, the operation of increasing the engine speed to the target value in step S7 is based on the determination result that the real-time pressure P of the hydraulic pump enters the second gear range B2 < P < B3, and an active preventive measure is executed; the active preventive measure increases the target speed by increasing the engine speed through the engine controller, so that the engine operates in a higher base speed range.

[0027] In one embodiment of the present invention, steps S13 and S14 are used to optimize combustion and power enhancement control during the stage of slight decrease in engine speed; when it is determined that the speed deviation ∆N is within the first range D1≤∆N≤D2, the combustion optimization step is executed first:

[0028] By increasing the rail pressure, the diesel injection pressure is increased, which promotes the atomization quality of fuel in the cylinder. At the same time, by increasing the injection timing, the time when diesel is injected into the cylinder is advanced, which prolongs the mixing time of fuel and air. When the smoke measurement value reaches the rated threshold, it is determined that the smoke is effectively controlled, the cyclic injection quantity is increased, and then the injection quantity compensation in step S14 is executed.

[0029] In one embodiment of the present invention, step S15 determines that ∆N is greater than the threshold D2 based on the speed deviation signal, indicating that the engine speed has dropped to a dangerously low level range.

[0030] Secondly, the present invention provides a control system for preventing a drop in crane speed during hoisting operations. Based on the same concept as the aforementioned control method for preventing a drop in crane speed during hoisting operations, the present invention is characterized by comprising multiple execution modules, wherein the execution modules implement the aforementioned control method for preventing a drop in crane speed during hoisting operations when running.

[0031] Thirdly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the aforementioned control method for preventing a drop in speed during crane hoisting operations.

[0032] Fourthly, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the aforementioned control method for preventing speed drops during crane hoisting operations.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] This invention uses comprehensive monitoring and logical judgment to provide early warning of engine speed drop risk under hoisting and pressure buildup conditions, and accurately judges different danger levels from the presence of risk to imminent engine shutdown.

[0035] This invention improves the response speed of the engine controller to sudden load increases by actively correcting the PID adaptive correction function.

[0036] This invention employs a tiered, interconnected control strategy. When the engine speed drops slightly, it prioritizes optimizing the combustion process and then increases fuel injection to enhance power, thereby achieving synergistic optimization of power enhancement and emission control. Attached Figure Description

[0037] Figure 1 This is a preferred flow diagram of a control method for preventing crane speed drops during hoisting operations provided by the present invention;

[0038] Figure 2 This is a partial flowchart of steps S1-S8 in the overall process of the control method for avoiding speed drop during crane hoisting operations provided by the present invention.

[0039] Figure 3 This is a partial flowchart of steps S9-S16 in the overall process of the control method for avoiding speed drop during crane hoisting operations provided by the present invention. Detailed Implementation

[0040] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0041] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0042] Example 1:

[0043] This invention provides a control method for preventing the speed drop of a crane during hoisting operations, comprising the following steps:

[0044] S1: Obtain the real-time hydraulic pump pressure P and the real-time engine speed N of the crane;

[0045] S2: Calculate the rate of change P' of the real-time pressure P of the hydraulic pump;

[0046] S3: Compare the rate of change P' with the first preset threshold A. If P' is greater than A, it is determined that the hydraulic pump pressure is increasing rapidly.

[0047] S4: Compare the real-time pressure P of the hydraulic pump with the first pressure range. If P is within the first range B1≤P≤B2, it is determined that the pump pressure is too high and there is a risk of speed drop.

[0048] S5: When it is determined that the engine speed is about to drop, the PID parameters of the engine controller are corrected in real time. Specifically, this includes: superimposing a positive bias on the proportional correction coefficient ΔKp, superimposing a negative bias on the integral correction coefficient ΔKi, and superimposing a negative bias on the derivative correction coefficient ΔKd, in order to improve the controller's response speed in advance. Among them, the initial reference parameters Kp0, Ki0, and Kd0 of the PID controller are obtained based on the engine bench test calibration. The real-time corrected PID parameters are calculated by the following formula: Kp = Kp0 + ΔKp, Ki = Ki0 + ΔKi, Kd = Kd0 + ΔKd. The PID output control quantity ε corresponds to the fuel injection quantity, fuel injection pulse width, or target torque. Its calculation formula is: ε = Kp * e + Ki * ∫ e dt + Kd * de / dt, where e is the speed deviation.

[0049] S6: If the real-time pressure P of the hydraulic pump is in the second range B2 < P < B3, it is determined that the pump pressure is too high and the engine will soon face a significant drop in speed.

[0050] S7: If step S6 determines that the pump pressure is too high, increase the engine speed to the target value to increase the engine's maximum torque and power, thereby reducing the risk of speed drop.

[0051] S8: If the real-time pressure P of the hydraulic pump is in the third range, it is determined that the pump pressure is particularly high and the engine is at risk of being shut down by the pressure.

[0052] S9: Calculate the rate of decrease N' of the real-time engine speed N;

[0053] S10: Compare the descent rate N' with the limit C. If N' reaches or exceeds C, it is determined that the speed drops too fast, the hydraulic pump requires more power than the engine output power, and the engine is at risk of being shut down by the pressure.

[0054] S11: Calculate the engine speed deviation ∆N based on the difference between the real-time engine speed N and the target speed;

[0055] S12: If the speed deviation ∆N is within the first range D1≤∆N≤D2, then the engine speed is determined to have decreased slightly;

[0056] S13: If step S12 determines that the engine speed has slightly decreased, the diesel injection pressure is adjusted to increase the rail pressure, and the diesel injection time is adjusted to increase the timing, thereby improving diesel atomization, extending the mixing time, promoting complete combustion and effectively reducing smoke.

[0057] S14: Based on the effect of step S13, increase the amount of diesel fuel injected into the cylinder until the smoke level meets the standard. Increasing the amount of fuel injected can improve power output to slow down the drop in engine speed, while keeping the smoke level consistent with the original state.

[0058] S15: If the speed deviation ∆N is greater than the second threshold D2, it is determined that the engine speed has dropped to a low level and there is a risk of being stalled.

[0059] S16: If the judgment conditions of steps S8, S10 and S15 are met simultaneously, it is accurately determined that the engine is about to be shut down. The displacement of the hydraulic pump is immediately reduced to lower the pump pressure, so that the power demand of the hydraulic system is significantly lower than the power output value of the engine, thereby causing the engine speed to recover quickly and preventing the engine from shutting down.

[0060] Specifically, this implementation continuously acquires the real-time pressure P of the crane's hydraulic system and the real-time engine speed N through the vehicle controller and engine controller. The system then calculates the rate of change P' of the hydraulic pump pressure. When this rate exceeds a preset threshold A, it determines that the hydraulic system is experiencing a sudden load. Simultaneously, the system compares the real-time pressure P with a pre-defined pressure range. If the pressure is in the medium-high range (B1≤P≤B2), it determines there is a clear risk of speed drop. At this point, the system enters a preventative control phase. The engine controller actively intervenes in three core parameters of its internal PID speed controller: increasing the proportional coefficient ΔKp to enhance the immediate response to speed deviations; and simultaneously reducing the integral coefficient ΔKi and the derivative coefficient ΔKd to suppress excessive cumulative effects and potential overshoot caused by derivative lead, thereby optimizing the controller's dynamic characteristics before the actual speed drop and preparing for rapid response. If the system determines the situation is more severe, with the pressure entering a higher range (B2<P<B3), the system actively increases the engine's target speed value, causing it to operate at a higher speed platform, thereby directly increasing the engine's torque reserve and power output capability. In extreme cases, the system calculates the real-time rate of engine speed decrease N' and the absolute value deviation ∆N. When the hydraulic pump pressure is in its highest range, the rate of speed decrease N' exceeds the limit C, and the speed deviation ∆N also falls below the safety threshold D2, all three conditions are met simultaneously, and the engine is determined to be about to stall. During the slight speed decrease phase (D1≤∆N≤D2), the control system first increases the rail pressure of the high-pressure common rail system and advances the injection timing to improve the fuel mist mixing quality, increase combustion efficiency, and reduce black smoke. While ensuring controllable smoke levels, it then moderately increases the circulating fuel injection quantity to obtain additional power compensation without exceeding environmental standards. When the system determines that the engine is about to stall, it bypasses engine control and directly sends a command to the hydraulic pump to reduce its displacement, forcibly reducing the power demand of the hydraulic system, instantly relieving the engine's burden, allowing its speed to recover rapidly, and fundamentally preventing stalling.

[0061] The core effect of this embodiment is that it changes the traditional passive response mode. Instead of waiting for a significant drop in engine speed before increasing fuel injection, it anticipates sudden load increases by integrating hydraulic system pressure trends and levels. By optimizing PID control parameters in advance, the control system can unleash powerful torque compensation capabilities when facing an impending drop in engine speed, nipping the speed drop in the bud. For more severe operating conditions, increasing the target engine speed directly enhances the engine's power reserve. When the engine speed has already begun to drop slightly, the control method creatively prioritizes combustion optimization instead of blindly increasing fuel injection. This successfully solves the problem of excessive black smoke caused by over-injection, achieving a balance between power enhancement and emission control. Finally, through cross-validation of pressure, speed drop rate, and drop amount, the system can accurately predict the possibility of engine shutdown and, by directly intervening in the load source, ensures that the engine speed can safely and quickly recover under various extreme pressure conditions, guaranteeing the safety and continuity of crane operations.

[0062] In a preferred embodiment, the specific method for obtaining the real-time hydraulic pump pressure P and the real-time engine speed N of the crane in step S1 is as follows: the real-time hydraulic pump pressure P is output through the vehicle controller, and the real-time engine speed N is output through the engine controller.

[0063] Specifically, this implementation method clarifies the specific architecture of system data interaction. The real-time hydraulic pump pressure P is collected and processed by the vehicle controller, which is responsible for the management and coordination of the vehicle's hydraulic system, and outputs the signal. This signal originates from a pressure sensor installed at the hydraulic pump outlet or on the main oil line. The real-time engine speed N is precisely calculated by the engine controller ECU using a crankshaft position sensor signal. The two controllers communicate in real time via a high-speed vehicle network, such as a CAN bus.

[0064] In one embodiment of the present invention, step S5 generally performs a fuzzy PID adaptive correction function; the fuzzy PID adaptive correction function is based on real-time monitoring of the hydraulic pump pressure change rate P' and the current pressure gear, and biases the PID output correction value in advance before the actual decrease in engine speed occurs, actively applying a predetermined bias adjustment to the proportional, integral, and derivative coefficients of the PID controller; if a decreasing trend in speed is detected, the PID controller after bias adjustment can immediately generate a large positive deviation correction output.

[0065] Specifically, this implementation further specifies the PID parameter correction steps, achieving fuzzy PID adaptive correction. When the hydraulic system meets the combined conditions of rapid pressure change and high pressure level, the system determines that the speed risk level has increased. At this time, the control algorithm immediately calls a set of preset PID biases to superimpose the original calibration parameters. This process occurs when the engine speed is still stable, but the external load threat has already appeared, making the system more sensitive to impending speed deviations.

[0066] In one embodiment of the present invention, the operation of increasing the engine speed to the target value in step S7 is based on the determination result that the real-time pressure P of the hydraulic pump enters the second gear range B2 < P < B3, and an active preventive measure is executed; the active preventive measure increases the target speed by increasing the engine speed through the engine controller, so that the engine operates in a higher base speed range.

[0067] In one embodiment of the present invention, steps S13 and S14 are used to optimize combustion and power enhancement control during the stage of slight decrease in engine speed; when it is determined that the speed deviation ∆N is within the first range D1≤∆N≤D2, the combustion optimization step is executed first:

[0068] Specifically, by increasing the rail pressure to improve the diesel injection pressure, the atomization quality of the fuel in the cylinder is improved. At the same time, by increasing the injection timing, the time when diesel is injected into the cylinder is advanced, thus extending the mixing time between the fuel and air. When the smoke opacity measurement value reaches the rated threshold, it is determined that the smoke opacity is effectively controlled, the cyclic injection quantity is increased, and then the injection quantity compensation in step S14 is executed.

[0069] In one embodiment of the present invention, step S15 determines that ∆N is greater than the threshold D2 based on the speed deviation signal, indicating that the engine speed has dropped to a dangerously low level range.

[0070] Specifically, this implementation focuses on identifying the last critical signal that the engine is about to stall. It sets a hard safety threshold D2 for speed deviation. The system continuously calculates the deviation ∆N between the current actual engine speed and the target speed. Once the deviation ∆N exceeds the threshold D2, the control system determines that the speed has dropped too low, deviating from the normal or slightly fluctuating range and entering a danger zone. The threshold D2 is obtained through experimental calibration based on the engine's idling stability, minimum operating speed, and hydraulic system characteristics.

[0071] Example 2:

[0072] This embodiment provides a control system to prevent crane speed drops during hoisting operations. Based on the same concept as the aforementioned control method for preventing crane speed drops during hoisting operations, it is characterized by including multiple execution modules, which implement the aforementioned control method for preventing crane speed drops during hoisting operations when running.

[0073] Example 3:

[0074] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor, when executing the computer program, implements the aforementioned method for controlling the speed of a crane during hoisting operations.

[0075] Example 4:

[0076] This embodiment provides a non-transitory computer-readable storage medium storing a computer program thereon, characterized in that the computer program, when executed by a processor, implements the aforementioned control method for preventing speed drops during crane hoisting operations.

[0077] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A control method for preventing speed drops during crane hoisting operations, characterized in that, Includes the following steps: S1: Obtain the real-time hydraulic pump pressure P and the real-time engine speed N of the crane; S2: Calculate the rate of change P' of the real-time pressure P of the hydraulic pump; S3: Compare the rate of change P' with the first preset threshold A. If P' is greater than A, it is determined that the hydraulic pump pressure is increasing rapidly. S4: Compare the real-time pressure P of the hydraulic pump with the first pressure range. If P is within the first range B1≤P≤B2, it is determined that the pump pressure is too high and there is a risk of speed drop. S5: When it is determined that the engine speed is about to drop, the PID parameters of the engine controller are corrected in real time. Specifically, this includes: superimposing a positive bias on the proportional correction coefficient ΔKp, superimposing a negative bias on the integral correction coefficient ΔKi, and superimposing a negative bias on the derivative correction coefficient ΔKd, in order to improve the controller's response speed in advance. Among them, the initial reference parameters Kp0, Ki0, and Kd0 of the PID controller are obtained based on the engine bench test calibration. The real-time corrected PID parameters are calculated by the following formula: Kp = Kp0 + ΔKp, Ki = Ki0 + ΔKi, Kd = Kd0 + ΔKd. The PID output control quantity ε corresponds to the fuel injection quantity, fuel injection pulse width, or target torque. Its calculation formula is: ε = Kp * e + Ki * ∫ e dt + Kd * de / dt, where e is the speed deviation. S6: If the real-time pressure P of the hydraulic pump is in the second range B2 < P < B3, it is determined that the pump pressure is too high and the engine will soon face a significant drop in speed. S7: If step S6 determines that the pump pressure is too high, increase the engine speed to the target value to increase the engine's maximum torque and power, thereby reducing the risk of speed drop. S8: If the real-time pressure P of the hydraulic pump is in the third range, it is determined that the pump pressure is particularly high and the engine is at risk of being shut down by the pressure. S9: Calculate the rate of decrease N' of the real-time engine speed N; S10: Compare the descent rate N' with the limit C. If N' reaches or exceeds C, it is determined that the speed drops too fast, the hydraulic pump requires more power than the engine output power, and the engine is at risk of being shut down by the pressure. S11: Calculate the engine speed deviation ∆N based on the difference between the real-time engine speed N and the target speed; S12: If the speed deviation ∆N is within the first range D1≤∆N≤D2, then the engine speed is determined to have decreased slightly; S13: If step S12 determines that the engine speed has slightly decreased, the diesel injection pressure is adjusted to increase the rail pressure, and the diesel injection time is adjusted to increase the timing, thereby improving diesel atomization, extending the mixing time, promoting complete combustion and effectively reducing smoke. S14: Based on the effect of step S13, increase the amount of diesel fuel injected into the cylinder until the smoke level meets the standard. Increasing the amount of fuel injected can improve power output to slow down the drop in engine speed, while keeping the smoke level consistent with the original state. S15: If the speed deviation ∆N is greater than the second threshold D2, it is determined that the engine speed has dropped to a low level and there is a risk of being stalled. S16: If the judgment conditions of steps S8, S10 and S15 are met simultaneously, it is accurately determined that the engine is about to be shut down. The displacement of the hydraulic pump is immediately reduced to lower the pump pressure, so that the power demand of the hydraulic system is significantly lower than the power output value of the engine, thereby causing the engine speed to recover quickly and preventing the engine from shutting down.

2. The control method for preventing speed drops during crane hoisting operations according to claim 1, characterized in that, In step S1, the specific method for obtaining the real-time hydraulic pump pressure P and the real-time engine speed N of the crane is as follows: the real-time hydraulic pump pressure P is output through the vehicle controller, and the real-time engine speed N is output through the engine controller.

3. A control method for preventing speed drops during crane hoisting operations according to claim 2, characterized in that, Step S5 generally executes the fuzzy PID adaptive correction function; the fuzzy PID adaptive correction function is based on real-time monitoring of the hydraulic pump pressure change rate P' and the current pressure gear, and before the actual decrease in engine speed occurs, it biases the PID output correction value in advance, and actively applies a predetermined bias adjustment to the proportional, integral and derivative coefficients of the PID controller. If a decreasing trend in rotational speed is detected, the bias-adjusted PID controller can immediately generate a large positive deviation correction output.

4. The control method for preventing speed drops during crane hoisting operations according to claim 3, characterized in that, In step S7, the operation of increasing the engine speed to the target value is carried out by implementing proactive preventive measures based on the determination result that the real-time pressure P of the hydraulic pump enters the second gear range B2 < P < B3. The proactive preventive measures increase the target speed through the engine controller, so that the engine operates in a higher base speed range.

5. A control method for preventing speed drops during crane hoisting operations according to claim 4, characterized in that, Steps S13 and S14 are used to optimize combustion and power enhancement control during the slight decrease in engine speed; when the speed deviation ∆N is determined to be within the first range D1≤∆N≤D2, the combustion optimization step is executed first: By increasing the rail pressure, the diesel injection pressure is increased, which promotes the atomization quality of fuel in the cylinder. At the same time, by increasing the injection timing, the time when diesel is injected into the cylinder is advanced, which prolongs the mixing time of fuel and air. When the smoke measurement value reaches the rated threshold, it is determined that the smoke is effectively controlled, the cyclic injection quantity is increased, and then the injection quantity compensation in step S14 is executed.

6. A control method for preventing speed drops during crane hoisting operations according to claim 5, characterized in that, Step S15 determines that ∆N is greater than the threshold D2 based on the speed deviation signal, indicating that the engine speed has dropped to a dangerously low level range.

7. A control system for preventing speed drops during crane hoisting operations, based on the same concept as the control method for preventing speed drops during crane hoisting operations described in any one of claims 1-6, characterized in that, It includes multiple execution modules, which implement the control method for preventing the speed drop of a crane during hoisting operations when running.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements a control method for preventing the speed of a crane from dropping during hoisting operations, as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements a control method for preventing the speed drop during crane hoisting operations as described in any one of claims 1 to 6.

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