Method and system for accurate identification of hydraulic cylinder stroke

Abstract

This invention relates to the field of steel rolling production equipment technology, and particularly to a method and system for accurately identifying the stroke of a hydraulic cylinder. The method includes: installing a laser rangefinder above the transmission shaft connected to the moving part driven by the hydraulic cylinder; aligning the monitoring point of the laser rangefinder with the center position of the transmission shaft; detecting the lifting distance of the transmission shaft in real time; obtaining the actual stroke of the hydraulic cylinder or the position height of the moving part using a preset model formula; and performing closed-loop control of the hydraulic cylinder based on the calculation results. The advantages of this invention are: by detecting the lifting distance of the transmission shaft using a laser rangefinder and calculating it using a model formula considering the wear coefficient ( ) and impact vibration coefficient ( ), the actual stroke of the hydraulic cylinder can be accurately identified. Actual production verification shows that the position feedback accuracy of the moving part can be stably controlled within the range of 0.005-0.01mm, fully meeting the high-precision control requirements of the servo system in hot rolling production lines and effectively avoiding production accidents such as steel jamming and strip breakage.

Description

Technical Field

[0001] This invention relates to the field of steel rolling production equipment technology, and in particular to a method and system for accurately identifying the stroke of a hydraulic cylinder. Background Technology

[0002] In the hot-rolled strip production process, hydraulic balancing systems are widely used for the precision control of various key equipment. To achieve high-precision servo control, displacement sensors are typically used to acquire position feedback signals from hydraulic cylinders to form a closed-loop control system. Common displacement sensors often employ a magnetic scale integrated into the hydraulic cylinder; however, in situations with limited installation space or unique structural layouts, the sensor must be externally placed near the hydraulic cylinder.

[0003] For example, in a hot rolling production line, the position detection system for the B-roll of the hot coil box uses an external displacement sensor. However, the production line environment is extremely harsh, with adverse factors such as high temperature and moisture, large amounts of dust, and severe vibration. Furthermore, the external displacement sensor is often directly subjected to the scouring of cooling water, causing it to operate under high humidity, high temperature, and high pollution conditions for extended periods. These environmental factors easily lead to water or steam ingress into the displacement sensor, causing short circuits and resulting in distortion or loss of the position detection signal.

[0004] Due to inaccurate position feedback signals, the servo system cannot accurately control the stroke of the hydraulic cylinder, which leads to uncontrolled lifting of the support roller, ultimately causing major production accidents such as strip jamming and strip breakage, resulting in serious economic losses and production interruption risks for the company.

[0005] To address the aforementioned issues, those skilled in the art typically attempt to improve the protection level of external displacement sensors, such as by employing higher-level waterproof and dustproof packaging, or by adding protective covers and other isolation measures. However, under extremely harsh operating conditions, simply improving the sensor's own protection capabilities is insufficient to fundamentally solve the problem, and high-protection-level sensors are expensive, increasing equipment investment.

[0006] Therefore, how to accurately identify the stroke of hydraulic cylinders under harsh working conditions and avoid the failure of external sensors due to environmental influences has become a technical problem that urgently needs to be solved in hot rolling production. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for accurately identifying the stroke of a hydraulic cylinder, solving the technical problem that existing external displacement sensors are susceptible to environmental corrosion and detection failure under harsh working conditions such as high temperature, high humidity, and strong vibration. By using a laser rangefinder to detect the lifting distance of the transmission shaft and combining it with a preset model formula to calculate the actual position of the moving parts, the invention achieves indirect and accurate identification of the hydraulic cylinder stroke. This avoids direct exposure of the sensor to harsh environments, extends the service life of the detection element, improves the position feedback accuracy, and ensures the stable operation of the servo system. As a result, it effectively prevents production accidents caused by inaccurate position detection, reduces equipment maintenance costs, and ensures continuous and efficient production on the hot rolling production line.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A method for accurately identifying the stroke of a hydraulic cylinder, comprising: A laser rangefinder is installed above the transmission shaft connected to the moving parts driven by the hydraulic cylinder; Align the monitoring point of the laser rangefinder with the center position of the transmission shaft; The lifting distance of the transmission shaft is detected in real time using a laser rangefinder; Using a preset model formula, the actual stroke of the hydraulic cylinder or the position and height of the moving parts can be obtained; The hydraulic cylinder is controlled in a closed loop based on the calculation results.

[0009] The preset model formula is: ①; in: This indicates the lifting distance of the moving parts, in mm. This indicates the length of the connecting shaft of the moving part, in mm; This indicates the wear coefficient of each part's clearance; Indicates the impact vibration coefficient; This indicates the lifting distance of the transmission shaft detected by the laser rangefinder, in mm. This indicates the vertical distance from the laser detection point to the connection end of the motor reducer when the moving part is at its lowest position. The unit is mm.

[0010] The moving parts are the lifting roller conveyors used to carry and transport materials.

[0011] A system for accurately identifying the stroke of a hydraulic cylinder includes a hydraulic cylinder one, a hydraulic cylinder two, moving parts, a transmission shaft, a reducer, and a rangefinder; The piston rod of hydraulic cylinder one is hinged to one end of the moving part, and the piston rod of hydraulic cylinder two is hinged to the other end of the moving part; hydraulic cylinder one and hydraulic cylinder two are used to drive the moving part to move up and down. The other end of the moving part is connected to the transmission shaft via a connector, and the other end of the transmission shaft is connected to the output shaft of the shaft motor reducer via a connector. The shaft motor reducer provides rotational power to the moving part. The rangefinder is positioned above the drive shaft, with its monitoring point aligned with the center of the drive shaft, to detect the lifting distance of the drive shaft in real time.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. The lifting distance of the transmission shaft is detected by a laser rangefinder, taking into account the wear coefficient ( ) and impact vibration coefficient ( The model formula is used to calculate and can accurately identify the actual stroke of the hydraulic cylinder. Through actual production verification, the position feedback accuracy of the moving parts can be stably controlled within the range of 0.005-0.01mm, which fully meets the high-precision control requirements of the hot rolling production line for the servo system and effectively avoids production accidents such as steel jamming and strip breakage caused by inaccurate position detection. 2. The laser rangefinder is installed above the transmission shaft to keep it away from harsh environmental factors such as high temperature, water vapor, dust, and vibration. This avoids the problems of traditional external displacement sensors being directly washed by cooling water and intruded by steam. Practical applications show that after adopting this invention, the service life of the detection element is extended, the frequency of sensor replacement is greatly reduced, and the cost of spare parts procurement and equipment maintenance are reduced. 3. It can still work stably under harsh working conditions such as high temperature, high humidity, high dust, and strong vibration, and is not affected by direct scouring of cooling water and steam erosion, ensuring the continuity and reliability of position feedback signals; production statistics show that using this invention reduces the number of production interruptions caused by position detection failures and effectively ensures the continuous and stable operation of the hot rolling production line. 4. No modification is required to the existing hydraulic cylinder body. Only a laser rangefinder needs to be installed above the transmission shaft. The installation structure is simple, the construction period is short, and the modification cost is low. It is not only suitable for the lifting and lowering control of the coil support rollers in the hot rolling production line, but can also be widely used in other hydraulic cylinder stroke detection and control in situations where installation space is limited or the environment is harsh. It has good versatility and promotion value. Attached Figure Description

[0013] Figure 1 It is a schematic diagram of the hydraulic cylinder stroke system for accurate identification.

[0014] In the diagram: 1. Hydraulic cylinder one; 2. Moving parts; 3. Transmission shaft; 4. Laser rangefinder; 5. Shaft motor reducer; 6. Hydraulic cylinder two. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0016] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0017] Example 1: See Figure 1 A system for accurately identifying the stroke of a hydraulic cylinder includes a first hydraulic cylinder 1, a second hydraulic cylinder 6, a moving part 2, a transmission shaft 3, a transmission shaft motor reducer 5, and a laser rangefinder 4. The piston rod of the first hydraulic cylinder 1 is hinged to one end of the moving part 2, and the piston rod of the second hydraulic cylinder 6 is hinged to the other end of the moving part 2. The first hydraulic cylinder 1 and the second hydraulic cylinder 6 are used to synchronously drive the moving part 2 to move up and down. The other end of the moving part 2 is connected to the transmission shaft 3 via a connector, and the other end of the transmission shaft 3 is connected to the output shaft of the transmission shaft motor reducer 5 via a connector. The transmission shaft motor reducer 5 provides rotational power to the moving part 2. The moving part 2 is a lifting roller conveyor used to carry and transport materials. The laser rangefinder 4 is positioned above the transmission shaft 3, with its monitoring point aligned with the center of the transmission shaft 3, for real-time detection of the lifting distance of the transmission shaft 3.

[0018] A method for accurately identifying the stroke of a hydraulic cylinder, comprising: S1. Real-time detection of the lifting distance of the transmission shaft; During the operation of the hot rolling production line, the lifting distance of the transmission shaft 3 is monitored in real time using a laser rangefinder 4. The sampling frequency of the laser rangefinder 4 is set to 100Hz, and the detection accuracy is 0.001mm. In a certain production run, the laser rangefinder 4 detected the real-time lifting distance of the transmission shaft 3. It is 2.365mm.

[0019] S2. Calculate the lifting distance of the moving parts; The lifting distance of the transmission shaft detected in S1 Substitute the preset model formula to calculate the actual lifting distance of moving part 2. .

[0020] The preset model formula is: ①; in: This indicates the lifting distance of the moving parts, in mm. This indicates the length of the connecting shaft of the moving part, in mm; This indicates the wear coefficient of each part's clearance; Indicates the impact vibration coefficient; This indicates the lifting distance of the transmission shaft detected by the laser rangefinder, in mm. This indicates the vertical distance from the laser detection point to the connection end of the motor reducer when the moving part is at its lowest position. The unit is mm.

[0021] Length of the connecting shaft of the moving part The vertical distance from the laser detection point to the connection end of the motor reducer when the moving part's connecting shaft is at its lowest position is 1500mm. The wear coefficient of each part is 800mm. Take 0.98 (obtained from a table based on equipment operating time and wear level), impact vibration coefficient Take 1.02 (obtained from real-time monitoring by on-site vibration sensors).

[0022] Substitute the above parameters into formula ①: ; mm; The actual lifting distance of moving part 2 was calculated. It is 8.869mm (rounded to three decimal places).

[0023] S3. Perform closed-loop control on the hydraulic cylinder.

[0024] The actual lifting distance of the moving part 2 calculated in step S2. The deviation value (8.869 mm) is obtained by comparing it with the target setting value (9.000 mm). mm.

[0025] The PLC control system uses the deviation value By adjusting the output adjustment amount through PID parameters, the oil inlet quantity and oil inlet direction of hydraulic cylinder 1 and hydraulic cylinder 6 are controlled respectively, so that the moving part 2 rises precisely by 0.131mm to reach the target position.

[0026] Actual tracking verification shows that the position feedback accuracy of the moving part 2 is stable within the range of 0.005-0.01mm, fully meeting the control requirements of the hot rolling production line. Meanwhile, because the laser rangefinder 4 is installed above the transmission shaft, away from high-temperature moisture, it avoids the problem of easy damage to traditional external displacement sensors, extending the service life of the detection element.

[0027] This invention uses a laser rangefinder to detect the lifting distance of the transmission shaft, and takes into account the wear coefficient ( ) and impact vibration coefficient ( The model formula is used for calculation, which can accurately identify the actual stroke of the hydraulic cylinder. Actual production verification shows that the position feedback accuracy of the moving parts can be stably controlled within the range of 0.005-0.01mm, fully meeting the high-precision control requirements of the servo system in the hot rolling production line. This effectively avoids production accidents such as steel jamming and strip breakage caused by inaccurate position detection. The laser rangefinder is installed above the transmission shaft, keeping it away from harsh environmental factors such as high temperature, water vapor, dust, and vibration. This avoids the problems of traditional external displacement sensors being directly subjected to cooling water erosion and steam intrusion. Practical application shows that using this invention extends the service life of the detection element, significantly reduces the frequency of sensor replacement, and lowers spare parts procurement costs and equipment maintenance workload. It can operate stably under harsh conditions of high temperature, high humidity, high dust, and strong vibration, and is unaffected by direct scouring by cooling water and steam erosion, ensuring the continuity and reliability of position feedback signals. Production statistics show that using this invention reduces the number of production interruptions caused by position detection failures, effectively ensuring the continuous and stable operation of the hot rolling production line. No modification to the existing hydraulic cylinder body is required; only a laser rangefinder needs to be installed above the transmission shaft. The installation structure is simple, the construction period is short, and the modification cost is low. It is not only suitable for the lifting and lowering control of the coil support rollers in the hot rolling production line, but can also be widely used in other hydraulic cylinder stroke detection and control applications where installation space is limited or the environment is harsh. It has good versatility and promotional value.

Claims

1. A method for accurately identifying the stroke of a hydraulic cylinder, characterized in that, include: A laser rangefinder is installed above the transmission shaft connected to the moving parts driven by the hydraulic cylinder; Align the monitoring point of the laser rangefinder with the center position of the transmission shaft; The lifting distance of the transmission shaft is detected in real time using a laser rangefinder; Using a preset model formula, the actual stroke of the hydraulic cylinder or the position and height of the moving parts can be obtained; The hydraulic cylinder is controlled in a closed loop based on the calculation results.

2. The method for accurately identifying the stroke of a hydraulic cylinder according to claim 1, characterized in that, The preset model formula is as follows: ①； in: This indicates the lifting distance of the moving parts, in mm. This indicates the length of the connecting shaft of the moving part, in mm; This indicates the wear coefficient of each part's clearance; Indicates the impact vibration coefficient; This indicates the lifting distance of the transmission shaft detected by the laser rangefinder, in mm. This indicates the vertical distance from the laser detection point to the connection end of the motor reducer when the moving part is at its lowest position. The unit is mm.

3. The method for accurately identifying the stroke of a hydraulic cylinder according to claim 1, characterized in that, The moving parts are lifting roller conveyors used to carry and transport materials.

4. A system for accurately identifying the stroke of a hydraulic cylinder to implement the method as described in any one of claims 1-3, characterized in that, Includes hydraulic cylinder one, hydraulic cylinder two, moving parts, transmission shaft, reducer, and rangefinder; The piston rod of hydraulic cylinder one is hinged to one end of the moving part, and the piston rod of hydraulic cylinder two is hinged to the other end of the moving part; hydraulic cylinder one and hydraulic cylinder two are used to drive the moving part to move up and down. The other end of the moving part is connected to the transmission shaft via a connector, and the other end of the transmission shaft is connected to the output shaft of the shaft motor reducer via a connector. The shaft motor reducer provides rotational power to the moving part. The rangefinder is positioned above the drive shaft, with its monitoring point aligned with the center of the drive shaft, to detect the lifting distance of the drive shaft in real time.

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