A proportional valve anomaly monitoring method and system for hydraulic displacement device control

Abstract

This invention discloses a method for monitoring the abnormality of a proportional valve in the control of a hydraulic displacement device. The method specifically includes the following steps: S1, after starting the proportional valve, detecting the displacement or actual operating speed of the hydraulic displacement device within a sampling time; S2, detecting whether the displacement of the hydraulic displacement device within the sampling time is greater than the displacement within the sampling time at a reference speed, or whether the actual operating speed of the hydraulic displacement device is greater than the reference speed. If the detection result is yes, an abnormality signal for the proportional valve is issued. This invention achieves safety protection for the hydraulic displacement device controlled by the proportional valve during movement by detecting abnormalities in the proportional valve. For abnormal proportional valves, an alarm is issued and effective hydraulic power is cut off to prevent potential harm to the hydraulic displacement device and personnel caused by proportional valve malfunction.

Description

Technical Field

[0001] This invention belongs to the field of proportional valve control technology, and more specifically, this invention relates to a method and system for monitoring abnormalities in proportional valves used in the control of hydraulic displacement equipment. Background Technology

[0002] A proportional valve is a new type of hydraulic control device. It replaces the original control components of ordinary pressure valves, flow valves, and directional valves with a proportional electromagnet, continuously and proportionally controlling the pressure, flow rate, or direction of oil flow remotely according to the input electrical signal. Proportional valves generally have pressure compensation capabilities, and their output pressure and flow rate are unaffected by load changes. Existing proportional valve control systems typically consist of a PLC or host computer, a proportional valve driver, a proportional valve, actuators, and sensors. Integrated proportional valves combine the proportional valve driver and the proportional valve into one unit. These proportional valves control field actuators, such as hydraulic cylinders and hydraulic motors, to perform displacement or rotational movements. When debris flakes off the hydraulic pipe wall or foreign objects introduced into the hydraulic oil jam the valve core, preventing it from resetting, or when there is an abnormality in the proportional valve's electrical circuitry, the proportional valve may malfunction. If the operator fails to detect the malfunction in time and take emergency measures, such as immediately interrupting automatic mode and switching to manual mode in automatic mode, or immediately releasing the button or reset knob in manual mode, the hydraulic displacement equipment will directly run to its mechanical limit position. When the equipment is positioned in automatic mode, the abnormally rapid movement of the equipment due to a runaway proportional valve prevents the PLC from receiving the positioning completion signal within the scanning cycle, thus failing to control the proportional valve and the electrically controlled shut-off valve to close in a timely manner. Due to its sporadic nature and the abnormally rapid movement after a runaway valve, especially in automatic mode, operators find it difficult to make timely judgments, posing a serious threat to equipment operation and personal safety on site. Summary of the Invention

[0003] This invention provides a method for monitoring the abnormality of a proportional valve in hydraulic displacement equipment control, aiming to achieve automatic monitoring of proportional valve abnormalities.

[0004] This invention is implemented as follows: a method for monitoring abnormalities in a proportional valve used in the control of hydraulic displacement equipment, the method specifically including the following steps:

[0005] S1. After starting the proportional valve, detect the displacement or actual operating speed of the hydraulic displacement device within the sampling time.

[0006] S2. Check whether the displacement of the hydraulic displacement device within the sampling time is greater than the displacement within the sampling time at the reference speed, or whether the actual operating speed of the hydraulic displacement device is greater than the reference speed. If the detection result is yes, issue a proportional valve abnormality signal.

[0007] Furthermore, when the proportional valve is in closed-loop control mode, during stable operation of the hydraulic displacement device, the position value of the hydraulic displacement device is collected every set sampling time. Multiple position values ​​are collected continuously, and the displacement of the hydraulic displacement device in each sampling time is calculated and its absolute value is taken to obtain the maximum value Δpos.max and the average value of the displacement. If the maximum value Δpos.max and the average value If the displacement is greater than the displacement within the sampling time of the reference speed ref_speed, an abnormal proportional valve signal will be issued.

[0008] Furthermore, each time a proportional valve abnormality signal is issued, the alarm count is incremented by 1. If the alarm count exceeds the threshold, a proportional valve fault signal is issued.

[0009] Furthermore, when the proportional valve is in closed-loop control mode, if the displacement speed of the hydraulic displacement device exceeds the speed reference value ref_speed, the output of the proportional valve is automatically reduced. If the actual displacement speed of the hydraulic displacement device is still greater than the reference speed ref_speed when the proportional valve output drops below the threshold value, a proportional valve fault signal is issued.

[0010] Furthermore, when the proportional valve is in closed-loop control mode, when the hydraulic displacement device moves to a deceleration position at a set distance from the reference position value ref_pos, the output of the proportional valve is reduced to a threshold value. At the same time, after a set time, the actual displacement speed of the hydraulic displacement device is collected. If the actual displacement speed is greater than or equal to the speed reference ref_speed, a proportional valve fault signal is issued.

[0011] Furthermore, when the proportional valve is in manual control mode, the displacement of the hydraulic displacement device is collected within a sampling time during stable operation. The displacement is then compared with the displacement within the corresponding sampling time under the manual speed reference. If the result is yes, a proportional valve fault signal is determined.

[0012] Furthermore, based on the proportional valve fault signal interrupting the output of the proportional valve, the electrically controlled shut-off valve is immediately shut off, thereby stopping the drive of the hydraulic displacement equipment.

[0013] This invention is implemented as follows: a proportional valve anomaly monitoring system for hydraulic displacement equipment control, the system comprising:

[0014] A hydraulic displacement device based on proportional valve control, and a position encoder for acquiring the position of the hydraulic displacement device; the position encoder, proportional valve and PLC controller are connected in communication.

[0015] The PLC controller monitors the proportional valve based on the aforementioned method for monitoring anomalies in proportional valves controlled by pressure displacement equipment.

[0016] Furthermore, the PLC controller stores the speed reference value ref_speed, the position reference value ref_pos, and the deceleration position.

[0017] This invention achieves safety protection for hydraulic displacement equipment controlled by proportional valves during movement by detecting abnormalities in proportional valves. In case of abnormal proportional valves, an alarm is issued and effective hydraulic power is cut off to prevent damage to hydraulic displacement equipment and personnel that may be caused by the proportional valve malfunction. Attached Figure Description

[0018] Figure 1 A flowchart of a proportional valve anomaly monitoring method for hydraulic displacement equipment control provided in an embodiment of the present invention. Detailed Implementation

[0019] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0020] Figure 1 A flowchart of a proportional valve anomaly monitoring method for hydraulic displacement equipment control provided in this embodiment of the invention is shown below:

[0021] The hydraulic displacement device in this invention is a hydraulically driven mobile device. If its movement speed is too slow, it will only affect the work efficiency and will not cause safety hazards. For example, a proportional valve controls the hydraulic motor to drive the lateral movement of a fixed-length machine or a mobile saw, and a proportional valve controls the hydraulic cylinder to drive the saw's forward and backward sawing equipment.

[0022] S1. After starting the proportional valve, detect the displacement or actual operating speed of the hydraulic displacement device within the sampling time.

[0023] S2. Check whether the displacement of the hydraulic displacement device within the sampling time is greater than the displacement within the sampling time at the reference speed, or whether the actual operating speed of the hydraulic displacement device is greater than the reference speed. If the detection result is yes, issue a proportional valve abnormality signal.

[0024] In this embodiment of the invention, when the proportional valve is in closed-loop control mode, the PLC program provides a position reference value ref_pos and a speed reference value ref_speed. The displacement speed of the hydraulic displacement device during stable operation is collected, avoiding the response time of the proportional valve opening action. After a set time since the proportional valve starts, the initial position pos0 of the hydraulic displacement device is recorded. Then, the position value of the hydraulic displacement device is collected every set sampling time, continuously collecting n values, i.e., pos1, pos2, ..., pos(n). Then, the displacement of the hydraulic displacement device in each sampling time, Δpos1′, Δpos2′, ..., Δpos5′, i.e., pos1-pos0, pos2-pos1, pos3-pos2, pos(n)-pos(n-1), is calculated, and the absolute value is taken to calculate the maximum value Δpos.max and the average value of the displacement. If the maximum value Δpos.max and the average value If the displacement is greater than the speed reference ref_speed within the sampling time, a proportional valve abnormality signal is issued, and the alarm count is incremented by 1. If the alarm count exceeds the threshold, a proportional valve fault message is issued.

[0025] Taking a sampling time of 100ms and a sampling number of 6 as an example, after the initial position pos0 of the hydraulic displacement device, the position value of the hydraulic displacement device is collected every 100ms, for a total of five consecutive samplings: position pos1, position pos2, position pos3, position pos4, and position pos5. Then, pos1-pos0, pos2-pos1, pos3-pos2, pos4-pos3, and pos5-pos4 are calculated, and the absolute values ​​are taken to obtain the displacement values ​​Δpos1′, Δpos2′, Δpos3′, Δpos4′, and Δpos5′, respectively. These are grouped into sets of five, and the maximum and average displacement values ​​Δpos.max are calculated. If the maximum value Δpos.max and the average value If the displacement within 100ms is greater than the speed reference ref_speed, a proportional valve abnormality signal is issued, and the alarm count is incremented by 1. If the alarm count exceeds 2, a proportional valve fault signal is issued, the output of the proportional valve is interrupted, and the electrically controlled shut-off valve is immediately closed, thus stopping the drive of the hydraulic displacement equipment.

[0026] In this embodiment of the invention, when the proportional valve is in closed-loop control mode, when the hydraulic displacement device moves to a deceleration position at a set distance from the reference position value ref_pos, two actions are performed. One is to decelerate the hydraulic displacement device according to the set deceleration rate to make the positioning of the hydraulic displacement device more reliable, thereby reducing the output of the proportional valve until the output of the proportional valve drops below the threshold value. The other is to collect the actual displacement speed of the hydraulic displacement device after a set time. If the actual displacement speed of the hydraulic displacement device is still greater than the speed reference ref_speed, a proportional valve fault signal is issued, the proportional valve output is interrupted, the electrically controlled shut-off valve is immediately closed, and an audible and visual alarm is issued. When the hydraulic displacement device moves to a position close to the reference position value ref_pos, that is, to the deceleration position, the deceleration position is a set value within the range of the reference position ref_pos, and there are forward deceleration positions and reverse deceleration positions. In this example, the distance from the reference position ref_pos is 100mm. After the hydraulic displacement device moves to the deceleration position, a delay of 50ms is made before the actual displacement speed of the hydraulic displacement device is collected. If the actual displacement speed is greater than or equal to the speed reference ref_speed, a proportional valve fault signal is issued, the proportional valve output is immediately interrupted, the electrically controlled shut-off valve is immediately closed, and the drive of the hydraulic displacement device is stopped.

[0027] In this embodiment of the invention, when the proportional valve is in manual control mode, when the button is pressed or the knob is turned and held, the response time of the proportional valve opening action is avoided. During stable operation, the displacement of the hydraulic displacement device is collected within a sampling time. The displacement is compared with the displacement within the corresponding sampling time under the manual speed reference. If the detection result is yes, a proportional valve fault information is issued, the proportional valve output is immediately interrupted, the electrically controlled shut-off valve is closed, and an audible and visual alarm is issued.

[0028] The present invention also provides a proportional valve abnormality monitoring system for hydraulic displacement equipment control, the system comprising:

[0029] A hydraulic displacement device based on proportional valve control, and a position encoder for acquiring the position of the hydraulic displacement device. The position encoder, proportional valve and PLC controller are connected in communication. The PLC controller monitors the proportional valve based on the above-mentioned proportional valve anomaly monitoring method for controlling the hydraulic displacement device. The PLC controller stores the speed reference value ref_speed, the position reference value ref_pos, the deceleration position, the automatic positioning deviation range value, the forward and reverse threshold values ​​of the proportional valve, the forward acceleration, the forward deceleration, the reverse acceleration and the reverse deceleration.

[0030] Position encoders come in two types: linear and rotary. Linear position encoders are installed inside the hydraulic cylinder, while rotary position encoders are installed next to the hydraulic motor reducer and are coaxial with the reducer's output shaft.

[0031] This invention achieves safety protection for hydraulic displacement equipment controlled by proportional valves during movement by detecting abnormalities in proportional valves. In case of abnormal proportional valves, an alarm is issued and effective hydraulic power is cut off to prevent damage to hydraulic displacement equipment and personnel that may be caused by the proportional valve malfunction.

[0032] By tracking, collecting, and comparing the position values ​​of hydraulic displacement equipment within the sampling period, the status of proportional valves in hydraulic displacement equipment can be monitored in real time, and reliable protection can be provided when it is determined that the proportional valve is in a high-speed runaway state.

[0033] The present invention has been described by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for monitoring abnormalities in a proportional valve used in the control of hydraulic displacement equipment, characterized in that, The method specifically includes the following steps: S1. After starting the proportional valve, detect the displacement or actual operating speed of the hydraulic displacement device within the sampling time. S2. Check whether the displacement of the hydraulic displacement device within the sampling time is greater than the displacement within the sampling time at the reference speed, or whether the actual operating speed of the hydraulic displacement device is greater than the speed reference value. If the detection result is yes, issue a proportional valve abnormality signal. When the proportional valve is in closed-loop control mode, when the actual operating speed of the hydraulic displacement equipment exceeds the speed reference value ref_speed, the output of the proportional valve is automatically reduced. When the output of the proportional valve is detected to drop below the threshold value, if the actual displacement speed of the hydraulic displacement equipment is still greater than the speed reference value ref_speed, a proportional valve fault signal is issued. When the proportional valve is in closed-loop control mode, when the hydraulic displacement device moves to a deceleration position at a set distance from the position reference value ref_pos, the output of the proportional valve is reduced to the threshold value. At the same time, after a set time, the actual displacement speed of the hydraulic displacement device is collected. If the actual displacement speed is greater than or equal to the speed reference value ref_speed, a proportional valve fault signal is issued.

2. The method for monitoring abnormalities of proportional valves used in hydraulic displacement equipment control as described in claim 1, characterized in that, When the proportional valve is in closed-loop control mode, the position value of the hydraulic displacement device is collected every set sampling time during stable operation. Multiple position values ​​are collected continuously, and the displacement of the hydraulic displacement device in each sampling time is calculated and its absolute value is taken to obtain the maximum value ∆pos.max and the average value of the displacement. If the maximum value ∆pos.max and the average value If the displacement is greater than the speed reference value ref_speed within the sampling time, an abnormal proportional valve signal will be issued.

3. The method for monitoring abnormalities of proportional valves used in hydraulic displacement equipment control as described in claim 2, characterized in that, Each time a proportional valve malfunction signal is issued, the alarm count is incremented by 1. If the alarm count exceeds the threshold, a proportional valve fault signal is issued.

4. The method for monitoring abnormalities of proportional valves used in hydraulic displacement equipment control as described in claim 1, characterized in that, When the proportional valve is in manual control mode, the displacement of the hydraulic displacement device is collected within a sampling time during stable operation. The displacement is then compared with the displacement within the corresponding sampling time under the manual speed reference. If the result is yes, a proportional valve fault signal is determined.

5. The method for monitoring abnormalities of proportional valves used in hydraulic displacement equipment control as described in claim 1, 3, or 4, characterized in that, If the proportional valve output is interrupted by a fault signal, the electrically controlled shut-off valve is immediately shut off, thus stopping the drive of the hydraulic displacement equipment.

6. A proportional valve anomaly monitoring system for hydraulic displacement equipment control, characterized in that, The system includes: A hydraulic displacement device based on proportional valve control, and a position encoder for acquiring the position of the hydraulic displacement device; the position encoder, proportional valve and PLC controller are connected in communication. The PLC controller monitors the proportional valve based on the proportional valve anomaly monitoring method for hydraulic displacement equipment control as described in any one of claims 1 to 5.

7. The proportional valve anomaly monitoring system for hydraulic displacement equipment control as described in claim 6, characterized in that, The PLC controller stores the speed reference value ref_speed, the position reference value ref_pos, and the deceleration position.

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