Excavator tool safety control system with flow maintaining function and working method of excavator tool safety control system

Abstract

The invention discloses an automatic control safety system for a multifunctional machine tool of an excavator, comprising a pressure sensor which monitors the pressure of an oil inlet path and an oil return path of a hydraulic system of the machine tool in real time and is connected to the input end of a safety control unit; the safety control unit is used for analyzing and processing the pressure data, dynamically generating a control instruction and controlling the execution mechanism to work; the executing mechanism responds to the control instruction to implement safety protection and comprises a high-frequency proportional valve for adjusting the flow of a hydraulic oil way (mounted on the oil way); the normally-closed hydraulic lock valve is used for emergently cutting off an oil path (mounted on the oil path); the sound-light alarm device is used for giving an alarm in a cab to prompt an operator to deal with abnormity; the three are connected with the output end of the safety control unit; the invention further discloses a corresponding working method, through combination of the system and the method, intelligent identification and protection of three risks of mechanical jamming, pipeline breakage and motion out-of-control are achieved, and the hydraulic safety of engineering machinery is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a safety control system for excavators with flow retention function and its operating method. Background Technology

[0002] In the widespread application of modern construction machinery, multi-functional implements (such as rotatable tilting buckets and hydraulic wrists) have become important tools for improving excavator operating efficiency. To simplify operation, these implements are typically equipped with flow-holding technology; specifically, operators can control the implement's movement through the following steps: First, activate the implement's rotation by using the slide key on the handle; then, press the flow-holding button to lock the hydraulic system's flow, ensuring the implement continues to move even after the operator releases the slide key.

[0003] While this flow-maintaining technology improves operational convenience and efficiency in practical applications, it also introduces several safety hazards. First, when mechanical jamming occurs during operation, the pressure within the hydraulic system continuously rises, and existing systems often lack effective automatic protection mechanisms to address this situation. Second, the high-pressure hoses in the hydraulic system may suddenly rupture for various reasons, leading to machine malfunction and potentially causing serious accidents. Finally, unintended movements of the machine may result in collisions between equipment or injury to operators.

[0004] Currently, the main safety protection measure in the automatic control system of excavators is the installation of relief valves as overload protection devices. However, because relief valves only release pressure when it exceeds the limit, they cannot provide effective protection in the early stages of mechanical jamming or pipeline leakage. In cases of progressive jamming, the pressure gradually increases, and the relief valve cannot react in time, often leading to equipment damage. For minor pipeline leaks, relief valves also cannot provide early warning, which may cause serious malfunctions. Moreover, the detection of jamming and leakage in existing technologies mainly relies on manual judgment, which cannot achieve automatic and timely protection. Therefore, it is clear that the protection scheme relying solely on relief valves is no longer sufficient to meet the safety performance requirements of hydraulic systems in modern construction machinery. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a safety control system for excavators with flow retention function and its operating method. Primarily targeting hydraulic systems with flow retention function but only equipped with inlet and return oil pressure sensors, the safety control system extracts four-dimensional characteristic parameters (pressure difference ΔP, pressure change rate Rp, pressure fluctuation Fd, and pressure balance coefficient Bc) from the inlet and return oil pressure signals. These parameters are then analyzed and processed by a safety controller. Combined with a three-level response strategy (Level 1 warning, Level 2 flow restriction, and Level 3 emergency stop), the system achieves intelligent identification and protection against three main risks: mechanical jamming, pipeline rupture, and loss of control, effectively improving the safety of hydraulic systems in construction machinery.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a safety control system for excavators with flow retention function, comprising:

[0007] The pressure sensor is used to monitor the pressure in the inlet and outlet oil circuits of the hydraulic safety control system of the excavator's multi-functional implement in real time, and is connected to the input terminal of the safety control unit.

[0008] The safety control unit can handle multiple tasks simultaneously, ensuring the safety control system can respond quickly even in complex working environments. It can analyze and process pressure data collected by pressure sensors in real time and issue corresponding control commands promptly based on the analysis results.

[0009] The actuator is responsible for performing corresponding actions according to the instructions issued by the safety controller to achieve safety control of the hydraulic safety control system. It mainly includes: a high-frequency proportional valve, a normally closed hydraulic lock-up valve, and an audible and visual alarm device. The high-frequency proportional valve, normally closed hydraulic lock-up valve, and audible and visual alarm device are connected to the output terminal of the safety control unit. The high-frequency proportional valve and normally closed hydraulic lock-up valve are installed in the oil circuit of the hydraulic safety control system. Among them, the normally closed hydraulic lock-up valve is used to cut off the oil circuit of the hydraulic safety control system, the high-frequency proportional valve is used to regulate the flow of the oil circuit of the hydraulic safety control system, and the audible and visual alarm device is installed in the excavator cab to provide an alarm and remind the operator to pay attention to and deal with abnormal situations in a timely manner.

[0010] Furthermore, the audible and visual alarm device is installed in a conspicuous position in the excavator cab and consists of a warning light and a buzzer.

[0011] Furthermore, when the safety control system detects an anomaly, the safety controller will send corresponding control signals to the audible and visual alarm device according to different risk levels and types, triggering different modes of audible and visual signals such as flashing yellow warning light and intermittent buzzer alarm (Level 1 warning), slow flashing red light and continuous buzzer alarm (Level 2 current limiting), and continuous red light and high-frequency buzzer alarm (Level 3 emergency stop), to remind operators to pay attention to and deal with the abnormal situation in a timely manner.

[0012] Furthermore, the frequency response of the high-frequency proportional valve needs to reach above 50Hz to enable it to respond quickly to the commands of the safety controller.

[0013] Furthermore, the normally closed hydraulic lock-up valve has an operating time of no more than 80ms, which can cut off the oil circuit of the hydraulic safety control system in a very short time.

[0014] A method for operating a safety control system for excavators with flow retention function, the method comprising:

[0015] Four types of characteristic parameters: A multi-dimensional pressure characteristic analysis model was constructed. Based on the pressure signals of the oil inlet and return circuits of the hydraulic safety control system of the excavator's multi-functional implement, four types of characteristic parameters were extracted through mathematical modeling and algorithm design.

[0016] Risk identification: By real-time monitoring and analysis of four types of characteristic parameters extracted from the multi-dimensional pressure characteristic analysis model, combined with preset judgment rules, it can quickly and accurately identify three main risks: mechanical jamming, pipeline rupture, and motion loss of control. Among them, the identification types for these three main risks include: identification of mechanical jamming, identification of pipeline rupture, and identification of motion loss of control.

[0017] Three-level response strategy: In order to deal with different types and degrees of risks, a three-level response strategy is designed. The three levels of response strategy are: Level 1 warning, Level 2 flow restriction, and Level 3 emergency stop. By setting different levels of safety response measures, corresponding actions can be taken as soon as a risk occurs, minimizing the harm caused by the risk, while avoiding overreaction that may cause unnecessary interference to the normal operation of the equipment.

[0018] Furthermore, it also includes: fail-safe design: In order to prevent equipment from going out of control due to component failure, by configuring fail-safe design, it is ensured that the equipment automatically enters a safe state in the event of failure, effectively protecting the safety of personnel and equipment; when the safety control system detects a failure in the pressure sensor, safety controller or power supply, it will immediately activate the corresponding fail-safe mechanism;

[0019] Fail-safe mechanisms: When the pressure sensor fails, the safety control system switches to conservative mode and relaxes the threshold to avoid false alarms; when the safety controller fails, the hydraulic lock-up valve is triggered via hardwire; when the power is interrupted, the hydraulic lock-up valve is automatically activated to ensure that the equipment is in a safe state.

[0020] Furthermore, the four types of feature parameters:

[0021] (1) Pressure difference (ΔP): Pressure difference refers to the pressure difference between the inlet and outlet oil circuits. The calculation formula is: ΔP = P in -Pout Among them, P in P represents the inlet oil pressure. out This parameter represents the return oil pressure, which directly reflects the load. Under normal operating conditions, the pressure difference remains within a certain range. When the load increases, the pressure difference will increase accordingly; conversely, when the load decreases, the pressure difference will decrease. By monitoring changes in the pressure difference, the load on the hydraulic system can be understood in real time, providing basic information for subsequent risk identification.

[0022] (2) Pressure change rate (Rp): The pressure change rate refers to the rate of change of the pressure difference. Its calculation formula is: Rp = (ΔP / ΔP) / ΔP t -ΔP t-1 ) / Δt; where ΔP t ΔP represents the pressure difference at the current moment. t-1 Δt represents the pressure difference at the previous moment, and Δt represents the time interval. This parameter reflects the dynamic characteristics of pressure changes in the hydraulic system. During normal operation, the pressure change rate is relatively stable. However, if the system experiences abnormal conditions, such as mechanical jamming or pipeline rupture, the pressure difference will change drastically in a short period of time, causing the pressure change rate to increase rapidly. By monitoring the pressure change rate, sudden pressure changes can be detected in a timely manner, thereby quickly identifying potential safety risks.

[0023] (3) Pressure fluctuation degree (Fd): The pressure fluctuation degree is used to describe the amplitude of pressure fluctuation. Its calculation formula is: Fd

[0024] =max(P in )-min(P in The calculation is performed within a 10-second time window. This parameter can detect the stability of the system. In a stable hydraulic system, the fluctuation amplitude of the inlet oil pressure is small, and the pressure fluctuation degree is low. However, when the system experiences problems such as leakage or vibration, the pressure fluctuation amplitude will increase significantly, and the pressure fluctuation degree will also increase accordingly. By analyzing the pressure fluctuation degree, the stability and reliability of the hydraulic system can be effectively evaluated.

[0025] (4) Pressure balance coefficient (Bc): The pressure balance coefficient refers to the ratio of the inlet and return oil pressures, and its calculation formula is: Bc

[0026] =|P in P outThis parameter reflects the energy transfer efficiency in the hydraulic system. Under ideal conditions, there is a certain balance between the pressure in the inlet and return oil circuits of the hydraulic system, and the pressure balance coefficient remains within a relatively stable range. When an abnormal energy transfer occurs in the system, the balance between the inlet and return oil pressures will be broken, and the pressure balance coefficient will change significantly. By monitoring the pressure balance coefficient, problems in the energy transfer process of the hydraulic system can be detected in a timely manner, providing a basis for preventing risks such as loss of control.

[0027] Furthermore, the identification of the three main types of risks specifically includes:

[0028] Mechanical jamming identification: When the safety control system detects that the pressure change rate (Rp) exceeds the preset threshold and the pressure difference (ΔP) also exceeds the normal range, and this state continues for a certain period of time, the safety control system will determine that mechanical jamming has occurred.

[0029] Pipeline rupture identification: The safety control system mainly relies on changes in pressure fluctuation (Fd) and pressure balance coefficient (Bc) to determine pipeline rupture. When the pressure fluctuation suddenly increases beyond the normal range and the pressure balance coefficient shows abnormal changes, the safety control system will determine that a pipeline rupture has occurred.

[0030] Identification of motion malfunction: The conditions for a safety control system to determine motion malfunction are that the pressure balance coefficient (Bc) deviates from the normal range and the pressure difference (ΔP) fluctuates abnormally. By comprehensively analyzing these two characteristic parameters, the malfunction state of the hydraulic safety control system can be effectively identified, and alarms can be issued and measures can be taken in a timely manner.

[0031] Furthermore, the three-level response strategy specifically includes:

[0032] Level 1 warning: When the safety control system detects an abnormality in a single parameter, it will trigger a Level 1 warning. At this time, the safety control system will issue a warning signal to the operator by flashing a yellow warning light and intermittently sounding a buzzer, reminding the operator to pay attention to the abnormal state of the safety control system and to check and handle it in a timely manner.

[0033] Level 2 Flow Limiting: When the safety control system confirms that a blockage or leakage has occurred, it will enter the Level 2 flow limiting response. The safety control system will automatically adjust the opening of the proportional valve to reduce the flow output of the hydraulic safety control system, thereby reducing the load pressure on the safety control system and preventing damage to the safety control system due to overload. At the same time, the warning light in the cab will flash at a certain frequency to prompt the operator to take further measures.

[0034] Level 3 Emergency Stop: When the safety control system detects serious risks such as loss of control or sudden pipeline rupture, it will immediately initiate a Level 3 emergency stop response. The safety control system will quickly cut off the power to the proportional valve, activate the hydraulic lock-up valve, and lock the hydraulic safety control system to prevent the equipment from continuing to move and causing greater harm. At the same time, it will trigger the audible and visual alarm device to warn the operators and surrounding personnel to pay attention to safety and carry out emergency evacuation.

[0035] The beneficial effects of this invention are:

[0036] (1) This invention extracts four-dimensional characteristic parameters from the two pressure signals of the oil inlet and return circuits through a multi-dimensional pressure characteristic analysis model, namely pressure difference (ΔP), pressure change rate (Rp), pressure fluctuation (Fd) and pressure balance coefficient (Bc). These parameters reflect the state of the hydraulic system from different perspectives such as load size, pressure change rate, system stability and energy transfer efficiency, and realize the comprehensive identification of three major risks: mechanical jamming, pipeline rupture and motion loss control.

[0037] (2) This invention designs a three-level response strategy to take corresponding measures according to the type and severity of the risk. Level 1 warning reminds the operator to pay attention to the abnormality through sound and light signals; Level 2 flow restriction reduces the hydraulic flow when jamming or leakage is confirmed, so as to reduce the system load; Level 3 emergency stop quickly locks the hydraulic system when serious risks such as loss of control of motion or pipeline rupture are detected, so as to prevent accidents and effectively protect the safety of equipment and personnel.

[0038] (3) The hardware cost of this invention is optimized. It only relies on pressure sensors in the oil inlet and oil return circuits, without the need to install additional angle, flow and other sensors, which significantly reduces the hardware cost. It can achieve effective safety protection at a lower cost and has broad application prospects and market competitiveness.

[0039] (4) This invention enables intelligent identification and protection against three main risks: mechanical jamming, pipeline rupture, and loss of motion control, effectively improving the safety of hydraulic systems for engineering machinery.

[0040] (5) This invention can be used not only for excavators, but also for other engineering machinery. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating the workflow of the method of the present invention;

[0042] Figure 2 This is a schematic diagram of the system of the present invention;

[0043] Figure 3 This is a schematic diagram of the three-level response strategy process in this invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0046] A safety control system for excavators with flow retention function, the hardware system of which mainly includes a pressure sensor, a safety control unit, and an actuator, such as... Figure 1-2 As shown,

[0047] Pressure sensor: The pressure sensor is one of the core components of the system. It is used to monitor the pressure of the hydraulic system's inlet and outlet oil circuits in real time. It is the inlet pressure sensor and the outlet pressure sensor, respectively. Its high measurement accuracy and high responsiveness can accurately reflect pressure changes, which enables the system to obtain the latest pressure data in a very short time, thereby promptly detecting potential safety hazards.

[0048] Safety Control Unit: As the "brain" of the system, the safety control unit employs a safety controller. This high-performance safety controller can handle multiple tasks simultaneously, ensuring the system can respond quickly even in complex working environments. Its processing capabilities enable real-time analysis and processing of pressure data collected by sensors, and it issues corresponding control commands promptly based on the analysis results. Furthermore, the safety controller's diagnostic coverage (DC) reaches over 85%, meaning it can detect over 85% of potential faults in the system, thereby significantly improving the system's reliability and safety. In this example, the safety control unit uses a PLC.

[0049] Actuators: The actuators are the "executors" of the safety control system, responsible for performing corresponding actions according to the instructions issued by the safety controller to achieve safe control of the hydraulic system. They mainly include high-frequency proportional valves, normally closed hydraulic lock-up valves, and audible and visual alarm devices. The high-frequency proportional valves have a frequency response of over 50Hz, allowing them to quickly respond to the safety controller's instructions and precisely regulate the hydraulic system's flow. The normally closed hydraulic lock-up valves have an action time of no more than 80ms, enabling them to cut off the hydraulic circuit in a very short time, effectively preventing system malfunction. This rapid response characteristic is crucial for preventing emergencies such as mechanical injuries. The audible and visual alarm devices are installed in a conspicuous location in the excavator's cab and typically consist of a warning light and a buzzer. When the system detects an anomaly, the safety controller sends corresponding control signals to the audible and visual alarm devices according to different risk levels and types, triggering different modes of audible and visual signals, such as flashing yellow warning lights and intermittent buzzer alarms (Level 1 warning), slow flashing red lights and continuous buzzer alarms (Level 2 flow limiting), and continuous red lights and high-frequency buzzer alarms (Level 3 emergency stop), to remind operators to pay attention to and handle the abnormal situation promptly.

[0050] like Figure 1 As shown, a control method for an excavator implement safety control system with flow retention function includes:

[0051] A multi-dimensional stress feature analysis model was constructed. Based on only two stress signals as input, four types of feature parameters were extracted through mathematical modeling and algorithm design, thereby achieving comprehensive identification of various risks.

[0052] Specifically, these four types of feature parameters include:

[0053] (1) Pressure difference (ΔP): Pressure difference refers to the pressure difference between the inlet and outlet oil circuits. The calculation formula is: ΔP = P in -P out Among them, P in P represents the inlet oil pressure. out This indicates the return oil pressure. This parameter directly reflects the load magnitude; under normal operating conditions, the pressure difference remains within a certain range; when the load increases, the pressure difference will increase accordingly; conversely, when the load decreases, the pressure difference will decrease; by monitoring changes in the pressure difference, the load on the hydraulic system can be understood in real time, providing basic information for subsequent risk identification.

[0054] (2) Pressure change rate (Rp): The pressure change rate refers to the rate of change of the pressure difference. Its calculation formula is: Rp = (ΔP / ΔP) / ΔP t -ΔP t-1 ) / Δt; where ΔP t ΔP represents the pressure difference at the current moment. t-1Δt represents the pressure difference at the previous moment, and Δt represents the time interval. This parameter reflects the dynamic characteristics of pressure changes in the hydraulic system. During normal operation, the pressure change rate is relatively stable. However, if the system experiences abnormal conditions, such as mechanical jamming or pipeline rupture, the pressure difference will change drastically in a short period of time, causing the pressure change rate to increase rapidly. By monitoring the pressure change rate, sudden pressure changes can be detected in a timely manner, thereby quickly identifying potential safety risks.

[0055] (3) Pressure fluctuation degree (Fd): The pressure fluctuation degree is used to describe the amplitude of pressure fluctuation. Its calculation formula is: Fd

[0056] =max(P in )-min(P in The calculation is performed within a 10-second time window. This parameter can detect the stability of the system; in a stable hydraulic system, the fluctuation range of the inlet oil pressure is small, and the pressure fluctuation degree is low; however, when the system has problems such as leakage or vibration, the pressure fluctuation range will increase significantly, and the pressure fluctuation degree will also increase accordingly; by analyzing the pressure fluctuation degree, the stability and reliability of the hydraulic system can be effectively evaluated.

[0057] (4) Pressure balance coefficient (Bc): The pressure balance coefficient refers to the ratio of the inlet and return oil pressures, and its calculation formula is: Bc

[0058] =|P in P out This parameter reflects the energy transfer efficiency in a hydraulic system. Ideally, there is a certain balance between the inlet and return pressures of a hydraulic system, with the pressure balance coefficient remaining within a relatively stable range. If an energy transfer anomaly occurs, such as loss of control, the balance between the inlet and return pressures will be disrupted, and the pressure balance coefficient will change significantly. By monitoring the pressure balance coefficient, problems in the energy transfer process of the hydraulic system can be detected in a timely manner, providing a basis for preventing risks such as loss of control.

[0059] By extracting and analyzing these four characteristic parameters, it is possible to comprehensively monitor the operating status of the hydraulic system with only inlet and outlet oil pressure sensors, promptly detect and identify various potential safety risks, and provide accurate basis for subsequent safety control measures.

[0060] Risk Identification: By real-time monitoring and analysis of the aforementioned multi-dimensional pressure characteristic parameters, combined with preset judgment rules, the system can quickly and accurately identify three main risks: mechanical jamming, pipeline rupture, and loss of control.

[0061] Mechanical jamming identification: When the system detects that the pressure change rate (Rp) exceeds the preset threshold and the pressure difference (ΔP) also exceeds the normal range, and this state continues for a certain period of time, the system will determine that mechanical jamming has occurred. This judgment logic takes into account the rate of pressure change and the magnitude of the pressure difference, which can effectively distinguish between normal load changes and real jamming situations, avoid false alarms and missed alarms, and ensure that protective measures can be taken in time when jamming occurs.

[0062] Pipeline rupture identification: The system primarily relies on changes in pressure fluctuation (Fd) and pressure balance coefficient (Bc) to determine pipeline rupture. When the pressure fluctuation suddenly increases beyond the normal range and the pressure balance coefficient shows abnormal changes, the system will determine that a pipeline rupture has occurred. This judgment rule is based on the violent pressure fluctuations and disruption of the inlet and return oil pressure balance caused by the pipeline rupture, which can promptly detect the occurrence of pipeline rupture and thus respond in a very short time to avoid serious accidents caused by pipeline rupture.

[0063] Identification of motion malfunction: The system determines motion malfunction when the pressure balance coefficient (Bc) deviates from the normal range and the pressure difference (ΔP) fluctuates abnormally. By comprehensively analyzing these two characteristic parameters, the system can effectively identify the malfunction state of the hydraulic system, issue timely alarms, and take measures to prevent accidents.

[0064] Three-level response strategy: To address different types and levels of risk, a three-level response strategy was designed, such as... Figure 3 As shown; this strategy, by setting different levels of safety response measures, can take appropriate actions at the first sign of a risk, minimizing the harm caused by the risk while avoiding unnecessary interference with normal equipment operation due to overreaction. The three-level response strategy includes:

[0065] Level 1 warning: When the system detects an abnormality in a single parameter, it will trigger a Level 1 warning. At this time, the system will issue a warning signal to the operator by flashing a yellow warning light and intermittently sounding a buzzer, reminding the operator to pay attention to the abnormal status of the system and to check and handle it in a timely manner.

[0066] Level 2 flow limiting: When the system confirms that a blockage or leakage has occurred, it will enter the Level 2 flow limiting response; the system will automatically adjust the opening of the proportional valve to reduce the flow output of the hydraulic system, so as to reduce the load pressure of the system and prevent the system from being damaged due to overload; at the same time, the warning light in the cab will flash at a certain frequency to prompt the operator to take further measures.

[0067] Level 3 Emergency Stop: When the system detects serious risks such as loss of control or sudden pipeline rupture, it will immediately initiate a Level 3 emergency stop response. The system will quickly cut off the power to the proportional valve, activate the hydraulic lock-up valve, lock the hydraulic system, and prevent the equipment from continuing to move and causing greater damage. At the same time, it will trigger the audible and visual alarm device to warn the operators and surrounding personnel to pay attention to safety and carry out emergency evacuation.

[0068] Fail-safe design: To prevent equipment malfunction due to component failure, this patent incorporates a fail-safe design to ensure the equipment automatically enters a safe state in the event of a failure, effectively protecting the safety of personnel and equipment. When the system detects a failure in a sensor, safety controller, or power supply, it immediately activates the corresponding fail-safe mechanism. For example, when a sensor fails, the system switches to a conservative mode, relaxing thresholds to avoid false alarms; when a safety controller fails, a hydraulic lock-up valve is triggered via hardwire; and when power is interrupted, the hydraulic lock-up valve automatically activates, ensuring the equipment remains in a safe state.

[0069] Example 1: Mechanical jamming protection

[0070] When an excavator is in operation, its implements may suddenly become mechanically jammed. In this situation, the pressure in the hydraulic system will rise rapidly. If measures are not taken in time, it may cause the hydraulic system to overload, damage the equipment, or even cause a more serious safety accident.

[0071] Protection process:

[0072] Characteristic parameter changes: At the moment of jamming, the system detected a sharp increase in the rate of pressure change (Rp), which exceeded the normal range; at the same time, the pressure difference (ΔP) also increased significantly.

[0073] Safety Response: The system quickly determines that there is mechanical jamming and triggers a Level 2 flow-limiting response. The proportional valve current decreases, reducing hydraulic flow output and lowering system pressure; the red light in the driver's cab flashes to alert the operator; if the jamming persists, the system further reduces the flow rate to 30% to protect the equipment. After the operator releases the jamming, pressing the reset button restores the system to normal operation.

[0074] Example 2: Protection against sudden pipeline rupture

[0075] When the high-pressure hose of the hydraulic system suddenly ruptures under a high working pressure of 32MPa, this sudden situation will cause the hydraulic oil to leak rapidly, the system pressure to drop sharply, and then cause the machine to lose control, posing a serious threat to the operator and the surrounding environment.

[0076] Protection process:

[0077] Characteristic mutation detection: At the moment of pipeline rupture, the system detects a sharp increase in pressure fluctuation (Fd) and abnormal fluctuation in pressure balance coefficient (Bc).

[0078] Safety Response: If the system detects a pipeline rupture, it immediately activates a Level 3 response. The proportional valve power is quickly cut off, the hydraulic lock-up valve is activated, and an audible and visual alarm is triggered. The system status is locked and requires inspection and repair by a professional, followed by emergency reset using a physical key to restore normal operation.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A safety control system for excavators with flow rate maintenance function, characterized in that, include: The pressure sensor is used to monitor the pressure in the inlet and outlet oil circuits of the hydraulic safety control system of the excavator's multi-functional implement in real time, and is connected to the input terminal of the safety control unit. The safety control unit can handle multiple tasks simultaneously, ensuring the safety control system can respond quickly even in complex working environments. It can analyze and process pressure data collected by pressure sensors in real time and issue corresponding control commands promptly based on the analysis results. The actuator is responsible for performing corresponding actions according to the instructions issued by the safety controller to achieve safety control of the hydraulic safety control system. It mainly includes: a high-frequency proportional valve, a normally closed hydraulic lock-up valve, and an audible and visual alarm device. The high-frequency proportional valve, normally closed hydraulic lock-up valve, and audible and visual alarm device are connected to the output terminal of the safety control unit. The high-frequency proportional valve and normally closed hydraulic lock-up valve are installed in the oil circuit of the hydraulic safety control system. Among them, the normally closed hydraulic lock-up valve is used to cut off the oil circuit of the hydraulic safety control system, the high-frequency proportional valve is used to regulate the flow of the oil circuit of the hydraulic safety control system, and the audible and visual alarm device is installed in the excavator cab to provide an alarm and remind the operator to pay attention to and deal with abnormal situations in a timely manner.

2. The excavator tool safety control system with flow maintenance function according to claim 1, characterized in that, The audible and visual alarm device is installed in a conspicuous position in the excavator's cab and consists of a warning light and a buzzer.

3. A safety control system for prompting and alarming lubricating oil replacement in a crusher according to claim 1, characterized in that, When the safety control system detects an anomaly, the safety controller will send corresponding control signals to the audible and visual alarm device according to different risk levels and types, triggering different modes of audible and visual signals such as flashing yellow warning light and intermittent buzzer alarm (Level 1 warning), slow flashing red light and continuous buzzer alarm (Level 2 current limiting), and continuous red light and high-frequency buzzer alarm (Level 3 emergency stop), to remind operators to pay attention to and deal with the abnormal situation in a timely manner.

4. The excavator tool safety control system with flow retention function according to claim 1, characterized in that, The frequency response of a high-frequency proportional valve needs to reach 50Hz or higher to enable it to respond quickly to the commands of the safety controller.

5. The excavator tool safety control system with flow retention function according to claim 1, characterized in that, The normally closed hydraulic lock valve has an operating time of no more than 80ms, which can cut off the oil circuit of the hydraulic safety control system in a very short time.

6. The working method of the excavator tool safety control system with flow maintenance function according to claim 1, characterized in that: The working method includes: Four types of characteristic parameters: A multi-dimensional pressure characteristic analysis model was constructed. Based on the pressure signals of the oil inlet and return circuits of the hydraulic safety control system of the excavator's multi-functional implement, four types of characteristic parameters were extracted through mathematical modeling and algorithm design. Risk identification: By real-time monitoring and analysis of four types of characteristic parameters extracted from the multi-dimensional pressure characteristic analysis model, combined with preset judgment rules, it can quickly and accurately identify three main risks: mechanical jamming, pipeline rupture, and motion loss of control. Among them, the identification types for these three main risks include: identification of mechanical jamming, identification of pipeline rupture, and identification of motion loss of control. Three-level response strategy: In order to deal with different types and degrees of risks, a three-level response strategy is designed. The three levels of response strategy are: Level 1 warning, Level 2 flow restriction, and Level 3 emergency stop. By setting different levels of safety response measures, corresponding actions can be taken as soon as a risk occurs, minimizing the harm caused by the risk, while avoiding overreaction that may cause unnecessary interference to the normal operation of the equipment.

7. The working method of the excavator tool safety control system with flow retention function according to claim 6, characterized in that: Also includes: Fail-safe design: To prevent equipment from going out of control due to component failure, a fail-safe design is configured to ensure that the equipment automatically enters a safe state in the event of a failure, effectively protecting the safety of personnel and equipment; when the safety control system detects a failure in the pressure sensor, safety controller, or power supply, it will immediately activate the corresponding fail-safe mechanism; Fail-safe mechanisms: When the pressure sensor fails, the safety control system switches to conservative mode and relaxes the threshold to avoid false alarms; when the safety controller fails, the hydraulic lock-up valve is triggered via hardwire; when the power is interrupted, the hydraulic lock-up valve is automatically activated to ensure that the equipment is in a safe state.

8. The working method of the excavator tool safety control system with flow retention function according to claim 6, characterized in that: The four types of feature parameters: (1) Pressure difference (ΔP): Pressure difference refers to the pressure difference between the inlet and outlet oil circuits. Its calculation formula is: ΔP P = P in - P out ; in, P in Indicates the oil inlet pressure. P out This parameter represents the return oil pressure, which directly reflects the load. Under normal operating conditions, the pressure difference remains within a certain range. When the load increases, the pressure difference will increase accordingly; conversely, when the load decreases, the pressure difference will decrease. By monitoring changes in the pressure difference, the load on the hydraulic system can be understood in real time, providing basic information for subsequent risk identification. (2) Pressure change rate (Rp): The pressure change rate refers to the rate of change of the pressure difference, and its calculation formula is: Rp= (Δ P t −Δ P t-1 ) / Δ t ; where Δ P t Δ represents the pressure difference at the current moment. P t-1 Δ represents the pressure difference at the previous moment. t The time interval is indicated by this parameter, which reflects the dynamic characteristics of pressure changes in the hydraulic system. During normal operation, the pressure change rate is relatively stable. However, if the system experiences abnormal conditions, such as mechanical jamming or pipeline rupture, the pressure difference will change drastically in a short period of time, causing the pressure change rate to increase rapidly. By monitoring the pressure change rate, sudden pressure changes can be detected in a timely manner, thereby quickly identifying potential safety risks. (3) Pressure fluctuation degree (Fd): The pressure fluctuation degree is used to describe the amplitude of pressure fluctuation, and its calculation formula is: Fd =max( P in )−min( P in The calculation is performed within a 10-second time window. This parameter can detect the stability of the system. In a stable hydraulic system, the fluctuation amplitude of the inlet oil pressure is small, and the pressure fluctuation degree is low. However, when the system experiences problems such as leakage or vibration, the pressure fluctuation amplitude will increase significantly, and the pressure fluctuation degree will also increase accordingly. By analyzing the pressure fluctuation degree, the stability and reliability of the hydraulic system can be effectively evaluated. (4) Pressure balance coefficient (Bc): The pressure balance coefficient refers to the ratio of the inlet and return oil pressures, and its calculation formula is as follows: Bc =| P in P out This parameter reflects the energy transfer efficiency in the hydraulic system. Under ideal conditions, there is a certain balance between the pressure in the inlet and return oil circuits of the hydraulic system, and the pressure balance coefficient remains within a relatively stable range. When an abnormal energy transfer occurs in the system, the balance between the inlet and return oil pressures will be broken, and the pressure balance coefficient will change significantly. By monitoring the pressure balance coefficient, problems in the energy transfer process of the hydraulic system can be detected in a timely manner, providing a basis for preventing risks such as loss of control.

9. The working method of the excavator tool safety control system with flow retention function according to claim 6, characterized in that: The identification of the three main types of risks specifically includes: Mechanical jamming identification: When the safety control system detects the rate of pressure change ( Rp If the pressure difference (ΔP) exceeds the preset threshold and the pressure difference (ΔP) also exceeds the normal range, and this state continues for a certain period of time, the safety control system will determine that mechanical jamming has occurred. Pipeline rupture identification: For determining pipeline rupture, the safety control system primarily relies on pressure fluctuations (…). Fd ) and pressure balance coefficient ( Bc The pressure fluctuation suddenly increases beyond the normal range, and the pressure balance coefficient changes abnormally. The safety control system will then determine that a pipeline rupture has occurred. Identification of motion loss of control: The condition for a safety control system to determine motion loss of control is the pressure balance coefficient (…). Bc If the pressure difference (ΔP) deviates from the normal range and fluctuates abnormally, the malfunction of the hydraulic safety control system can be effectively identified through comprehensive analysis of these two characteristic parameters, and timely alarms and measures can be taken.

10. The operating method of the excavator tool safety control system with flow retention function according to claim 6, characterized in that: The three-level response strategy specifically includes: Level 1 warning: When the safety control system detects an abnormality in a single parameter, it will trigger a Level 1 warning. At this time, the safety control system will issue a warning signal to the operator by flashing a yellow warning light and intermittently sounding a buzzer, reminding the operator to pay attention to the abnormal state of the safety control system and to check and handle it in a timely manner. Level 2 Flow Limiting: When the safety control system confirms that a blockage or leakage has occurred, it will enter the Level 2 flow limiting response. The safety control system will automatically adjust the opening of the proportional valve to reduce the flow output of the hydraulic safety control system, thereby reducing the load pressure on the safety control system and preventing damage to the safety control system due to overload. At the same time, the warning light in the cab will flash at a certain frequency to prompt the operator to take further measures. Level 3 Emergency Stop: When the safety control system detects serious risks such as loss of control or sudden pipeline rupture, it will immediately initiate a Level 3 emergency stop response. The safety control system will quickly cut off the power to the proportional valve, activate the hydraulic lock-up valve, and lock the hydraulic safety control system to prevent the equipment from continuing to move and causing greater harm. At the same time, it will trigger the audible and visual alarm device to warn the operators and surrounding personnel to pay attention to safety and carry out emergency evacuation.

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