Full-stroke detection oil cylinder for filling industrial pump and control method

Abstract

The invention relates to the technical field of hydraulic oil cylinders, in particular to a full-stroke detection oil cylinder for a filling industrial pump and a control method.The full-stroke detection oil cylinder for the filling industrial pump comprises an oil pump, a cylinder barrel, a piston, a piston rod, a sealing assembly, a guiding assembly, a guiding sleeve, a Hall magnetic-sensing position sensor and a PLC control system.The piston is internally provided with a throttling valve, and the cylinder barrel is provided with a liquid inlet, a liquid outlet and a sensor wiring port; the piston is slidably connected with the cylinder barrel, the sealing assembly and the guiding assembly are arranged on the piston, the guiding sleeve is installed on the cylinder barrel, one end of the piston rod penetrates through the guiding sleeve and is connected with the piston through the sealing assembly, the position sensor is connected with the piston rod, the oil pump is connected with the liquid inlet, and the position sensor is connected with the signal input end of the sensor through a sensor wiring port. The PLC control system is connected with a sensor wiring port, data processing is carried out through a Kalman filtering algorithm, the precision, stability and reliability can be improved, and the problems that the control capacity cannot be controlled and adjusted, and reversing impact is too large are solved.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic cylinders, and in particular to a full-stroke detection cylinder for filling an industrial pump and a control method thereof. Background Art

[0002] Hydraulic cylinder, also commonly referred to as hydraulic cylinder, is a key actuator in hydraulic system. It can convert hydraulic energy into mechanical energy and realize linear reciprocating motion (or swinging motion). In order to understand the working status of the cylinder, provide key data for system control and monitoring, ensure stable operation of equipment, improve production efficiency and prevent potential failures, it is usually necessary to detect the stroke of the cylinder.

[0003] There are many types of traditional cylinder stroke detection methods, but all of them have obvious shortcomings. For example, mechanical limit switches can only detect the arrival of the piston at a few specific fixed positions, and can only provide limited discrete position information. It is impossible to obtain the continuous change data of the cylinder throughout the entire stroke, which makes it difficult to achieve refined filling operations. In addition, mechanical limit switches are prone to failure due to wear, collision and other factors, and have poor reliability and require regular maintenance and replacement.

[0004] Another commonly used detection method uses a photoelectric sensor to determine the piston position by emitting and receiving light. However, this sensor is easily affected by environmental factors. In industrial environments full of dust, high humidity or complex light, its detection accuracy will be greatly reduced. Moreover, when detecting long strokes, due to the stability of the light propagation path and the accuracy limitations of optical components, its accuracy will gradually decrease as the stroke increases, making it difficult to meet the requirements of high-precision filling industrial pumps.

[0005] In summary, the existing cylinder stroke detection method has the problems of low accuracy, poor stability, low reliability, uncontrollable adjustment of the control quantity, and excessive switching impact. Summary of the invention

[0006] The purpose of the present invention is to provide a full-stroke detection cylinder and control method for a filling industrial pump, aiming to solve the technical problems of low accuracy, poor stability, low reliability, uncontrollable adjustment of control volume, and excessive switching impact in the cylinder stroke detection method in the prior art, thereby improving the overall performance of the filling industrial pump.

[0007] To achieve the above-mentioned purpose, the present invention adopts a full-stroke detection cylinder for a filling industrial pump, comprising an oil pump, a cylinder barrel, a piston, a piston rod, a sealing assembly, a guide assembly, a guide sleeve, a Hall magnetic position sensor and a PLC control system, wherein the cylinder barrel has a liquid inlet, a liquid outlet and a sensor wiring port, the piston is slidably connected to the cylinder barrel, the sealing assembly and the guide assembly are both arranged on the piston, the guide sleeve is installed on the cylinder barrel, one end of the piston rod passes through the guide sleeve and is connected to the piston through the sealing assembly, the Hall magnetic position sensor is connected to the piston rod, the oil pump is connected to the liquid inlet, the Hall magnetic position sensor is connected to the sensor signal input end through the sensor wiring port, the PLC control system is connected to the sensor wiring port, the piston has a built-in throttle valve for controlling the volume, and the Hall magnetic position sensor is used for stroke detection and reducing impact.

[0008] Among them, the Hall magnetic position sensor includes a Hall magnetic element and a magnetic float. The Hall magnetic element adopts an adaptive magnetic float floating structure. The Hall magnetic element is connected to the cylinder barrel, the magnetic float is arranged outside the Hall magnetic element, and the magnetic float is built into the hollow structure of the piston rod.

[0009] Wherein, the sealing assembly includes at least two sealing rings, and the sealing rings are both in contact with the piston and the piston rod.

[0010] Wherein, the guide assembly includes at least two guide rings, and the guide rings are connected to the piston and the cylinder.

[0011] Wherein, the full-stroke detection oil cylinder for filling industrial pump also includes an annular seal, and the annular seal is arranged on the piston.

[0012] The present invention also provides a control method for a full-stroke detection cylinder for a filling industrial pump, which is applied to the full-stroke detection cylinder for a filling industrial pump as described above.

[0013] The steps include:

[0014] Firstly, the sensor signal input end monitors the piston rod running position data in real time through the position sensor;

[0015] Afterwards, the monitored data is transmitted to the PLC control system;

[0016] Subsequently, the PLC control system adjusts the displacement of the oil pump;

[0017] Finally, the displacement is controlled by monitoring the piston position in real time.

[0018] Wherein, when monitoring the piston rod running position data, piston kinematics control and volume adjustment based on Kalman filter algorithm are adopted.

[0019] The full-stroke detection cylinder and control method for a filling industrial pump of the present invention, when in use, first, install the cylinder barrel on the base of the filling industrial pump, and ensure that it is installed firmly and horizontally; then, install the guide sleeve at the corresponding position of the cylinder barrel, use special tools to ensure its installation accuracy, fill with grease and install a sealing ring on the guide sleeve; then, insert the piston rod through the guide sleeve into the cylinder barrel, and connect the piston; when installing the piston, carefully install the sealing assembly to ensure its good sealing performance. At the same time, connect the signal transmission cable of the sensor in the piston rod and the signal transmission line inside the piston rod; connect the sensor signal input end, adjust its position and angle, so that it can accurately detect the position change of the piston; finally, connect the main oil pump with the liquid inlet and the liquid outlet of the cylinder to ensure tight connection and no leakage; during operation, the running position of the piston rod is detected by the Hall magnetic position sensor, and the detection result, i.e., the position information, is transmitted to the sensor signal input end, and the speed and acceleration are calculated according to the position information and instantaneous changes, and processed by the Kalman filter algorithm to obtain more accurate control data. Subsequently, the oil pump is adjusted for pumping volume through the PLC control system, and the cylinder position is monitored and regulated in real time to reduce the impact.

[0020] In this way, the problems of low accuracy, poor stability, low reliability, uncontrollable adjustment of control quantity, and excessive switching impact in the oil cylinder stroke detection method in the prior art are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a structural schematic diagram of a full-stroke detection oil cylinder for a filling industrial pump of the present invention.

[0023] Figure 2 The invention discloses a circuit schematic diagram of a full-stroke detection oil cylinder for a filling industrial pump.

[0024] Figure 3 The invention discloses a control principle block diagram of a full-stroke detection oil cylinder for a filling industrial pump.

[0025] 1-oil pump, 2-cylinder, 3-piston, 4-piston rod, 5-guide sleeve, 6-liquid inlet, 7-liquid outlet, 8-sensor wiring port, 9-Hall magnetic sensitive element, 10-magnetic float, 11-sealing ring, 12-guide ring, 13-annular seal, 14-sensor signal input terminal, 15-PLC control system. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0027] See also Figure 1 to Figure 3 ,in Figure 1 It is a structural schematic diagram of a full-stroke detection oil cylinder for a filling industrial pump of the present invention. Figure 2 The invention discloses a circuit schematic diagram of a full-stroke detection oil cylinder for a filling industrial pump. Figure 3 The invention discloses a control principle block diagram of a full-stroke detection oil cylinder for a filling industrial pump.

[0028] The present invention provides a full-stroke detection oil cylinder for a filling industrial pump, comprising an oil pump 1, a cylinder barrel 2, a piston 3, a piston rod 4, a sealing assembly, a guide assembly, a guide sleeve 5, a Hall magnetic position sensor and a PLC control system 15, wherein the cylinder barrel 2 has a liquid inlet 6, a liquid outlet 7 and a sensor wiring port 8, the piston 3 is slidably connected to the cylinder barrel 2, the sealing assembly and the guide assembly are both arranged on the piston 3, the guide sleeve 5 is installed on the cylinder barrel 2, one end of the piston rod 4 passes through the guide sleeve 5 and is connected to the piston 3 through the sealing assembly, the Hall magnetic position sensor is connected to the piston rod 4, the oil pump 1 is connected to the liquid inlet 6, the Hall magnetic position sensor is connected to the sensor signal input end 14 through the sensor wiring port 8, the PLC control system 15 is connected to the sensor wiring port 8, the piston 3 has a built-in throttle valve for controlling the volume, and the Hall magnetic position sensor is used for stroke detection and reducing impact.

[0029] The Hall magnetic position sensor includes a Hall magnetic element 9 and a magnetic float 10. The Hall magnetic element 9 adopts an adaptive magnetic float floating structure. The Hall magnetic element 9 is connected to the cylinder 2. The magnetic float 10 is arranged outside the Hall magnetic element 9, and the magnetic float is built into the hollow structure of the piston rod 4.

[0030] For this specific embodiment, when it is used, first, install the cylinder 2 on the base of the filling industrial pump, and ensure that it is firmly and horizontally installed. Then, install the guide sleeve 5 at the corresponding position of the cylinder 2, use special tools to ensure its installation accuracy, fill grease and install the sealing ring on the guide sleeve 5. Subsequently, insert the piston rod 4 into the cylinder 2 through the guide sleeve 5, connect the piston 3, and when installing the piston 3, carefully install the sealing assembly to ensure that its sealing performance is good. At the same time, connect the signal transmission cable of the sensor in the piston rod 4 and the signal transmission line inside the piston rod 4, and connect the sensor signal input terminal 14, adjust its position and angle, so that it can accurately detect the position change of the piston 3. Finally, connect the main oil pump 1 with the liquid inlet 6 and the liquid outlet 7 of the cylinder 2 to ensure a tight connection and no leakage. During operation, the running position of the piston rod 4 is detected by the Hall magnetic position sensor, and the detection result, i.e., the position information, is transmitted to the sensor signal input terminal 14, and the speed and acceleration are calculated according to the position information and instantaneous changes, and processed by the Kalman filter algorithm to obtain more accurate control data. Subsequently, the pumping volume of the oil pump 1 is adjusted through the PLC control system 15, and the oil cylinder position is monitored and regulated in real time to reduce the impact.

[0031] In this way, the problems of low accuracy, poor stability, low reliability, uncontrollable adjustment of control quantity and excessive switching impact in the oil cylinder stroke detection method in the prior art are solved.

[0032] The sealing assembly includes at least two sealing rings 11 , each of which is in contact with the piston 3 and the piston rod 4 , and is used to improve the seal between the piston 3 and the piston rod 4 .

[0033] Secondly, the guide assembly includes at least two guide rings 12 , each of which is connected to the piston 3 and the cylinder 2 , and is used to guide the piston 3 .

[0034] At the same time, the full-stroke detection oil cylinder for filling industrial pumps further includes an annular seal 13 , which is arranged on the piston 3 , and is used to seal the guide sleeve 5 .

[0035] In the full stroke detection cylinder for filling industrial pump:

[0036] The piston 3 is made of carbon fiber reinforced polymer material, which makes the piston 3 have a high strength-to-weight ratio, which can significantly reduce the inertia force of the oil cylinder, thereby improving the response speed and alleviating the problem of excessive impact. Local reinforcement materials are used at key locations such as contact parts and connection parts to further improve wear resistance.

[0037] The cylinder 2 is made of aluminum alloy cylinder 2, and the surface is covered with an anodic oxidation film to improve wear resistance and corrosion resistance. Such a lightweight cylinder 2 assembly design is conducive to improving energy efficiency and response speed in the equipment. The surface coating is a large contact angle super-hydrophobic bionic structure coating with self-cleaning and corrosion resistance functions. The two ends of the cylinder 2 are respectively equipped with an oil inlet and an oil outlet and a sensor wiring port 8, and a built-in microprocessor to detect the pressure, temperature, and movement of the cylinder 2 assembly, and alarm for abnormal conditions.

[0038] The Hall magnetic position sensor has the Hall magnetic element 9 built in, and the external magnetic float 10 detects the position state as the cylinder extends or retracts, can continuously measure the real-time position, and realize automatic control through the output of 4-20mA signal. The Hall magnetic element 9 adopts an ultra-miniaturized integrated design, and adopts a multi-array structure to improve the detection accuracy and resolution. The Hall magnetic displacement sensor adopts an adaptive floating structure of the magnetic float 10. The magnetic float 10 is connected to the piston rod 4 through a special elastic connection device. When the cylinder is subjected to lateral force or uneven load during operation, the elastic connection device can allow the magnetic float 10 to adaptively adjust its position within a certain range, and maintain a relatively stable magnetic field coupling relationship with the Hall magnetic element 9, thereby reducing the detection error caused by excessive changes in the magnetic field between the magnetic float 10 and the Hall magnetic element 9 due to cylinder vibration or eccentric load, thereby obtaining a high-stability detection effect and high control efficiency. A special magnetic material or magnetic conductive structure is arranged on the inner wall of the sensor housing to guide the magnetic field generated by the magnetic float 10 to the area where the Hall magnetic sensor 9 is located, thereby improving the utilization rate of the magnetic field and the sensitivity of the sensor. The displacement sensor continuously detects the position of the piston 3, and the output position signal is processed by the Kalman filter algorithm and output to the signal processing module for motion rate control, thereby reducing the impact and controlling the pumping volume as needed.

[0039] The piston rod 4 is a hollow structure, with a space reserved for the probe rod to move, the magnetic float 10 is installed inside, and a buffer protection device is configured. The piston rod 4 uses a magnetorheological fluid buffer element, which adjusts the viscosity and damping characteristics of the liquid by changing the electromagnetic field or electric field strength, thereby achieving an adaptive buffering effect, effectively reducing the impact and vibration of the piston 3 when it reaches the end of the stroke, and a built-in hydraulic accumulator absorbs and stores energy, releases energy when the piston rod 4 returns, assists the movement of the piston rod 4, improves energy utilization efficiency, and can also further reduce impact and vibration.

[0040] The guide sleeve 5 is a polyetheretherketone polymer self-lubricating guide sleeve 5 with a copper alloy base, which can maintain good lubrication performance in a wider temperature range and avoid failure under high working temperature.

[0041] The guide ring 12 is made of nano-reinforced material and base polymer, and the surface is covered with diamond carbon coating, which has significant hardness, strength, wear resistance and self-lubricating properties. The coating is covered by chemical vapor deposition technology. An adaptive gap adjustment structure is adopted, and the elastic expansion ring structure is utilized to set a circle of thin-walled elastic metal ring inside the guide ring 12. When the cylinder 2 or the piston 3 changes slightly in size due to temperature change or wear, the elastic metal ring can expand or contract adaptively to maintain a reasonable gap between the guide ring 12 and the matching parts, ensuring a good guiding effect.

[0042] The present invention also provides a control method for a full-stroke detection cylinder for a filling industrial pump, which is applied to the full-stroke detection cylinder for a filling industrial pump as described above.

[0043] The steps include:

[0044] First, the sensor signal input terminal 14 monitors the operating position data of the piston rod 4 in real time through the Hall magnetic position sensor;

[0045] Afterwards, the monitored data is transmitted to the PLC control system 15, and the PLC control system 15 calculates the speed and acceleration according to the position information and the instantaneous change, and processes them through the Kalman filter algorithm to obtain more accurate control data;

[0046] Then, the PLC control system 15 adjusts the displacement of the oil pump 1;

[0047] Finally, the displacement is controlled by monitoring the position of the piston 3 in real time.

[0048] When monitoring the piston rod operating position data, piston kinematics control and volume adjustment based on Kalman filter algorithm are adopted.

[0049] Among them, in the Kalman filter algorithm used in the control method, the state vector X k =[x k , v k ] T , where x k represents the position of piston rod 4 at time k, x k represents the speed X of piston rod 4 at time k k =F k X k-1 +B k u k +w k ;

[0050] Among them, F k is the state transfer matrix, which describes the evolution relationship of state variables at adjacent moments and is determined based on the kinematic principle of the cylinder; B k is the control input matrix, u k represents the control input acting on the system (such as the effect of the pressure change of the main oil pump 1 on the movement of the piston rod 4); w k is the system noise vector, which is used to consider model errors and other unmodeled interference factors. The measurement equation links the sensor's measurement value to the system state variable. Let the measurement vector Z k =[z k ], represents the position information of the piston rod 4 measured by the sensor, then the measurement equation is:

[0051] Z k =H k X k +v k ;

[0052] Among them, H k is the measurement matrix. Since the main measurement here is the position of the piston rod 4, H k =[1,0] T ;v k is the measurement noise vector, which follows a Gaussian distribution.

[0053] According to the optimal state estimation at the previous moment And the state equation, calculate the state prediction value at the current moment And the state prediction covariance matrix P k|k-1 =F k P k|k-1 F k T +Q k ;

[0054] At the same time, the Kalman gain is calculated:

[0055] K k =P k|k-1 Hk T (H k P k|k-1 H k T +R k ) -1 ;

[0056] According to the measured value Z k and the Kalman gain K k , update the state estimate:

[0057]

[0058] The post-update state estimate covariance matrix:

[0059] P k =(IK k H k ) k|k-1 .

[0060] By repeating the above prediction and update steps, the Kalman filter algorithm can effectively fuse the sensor measurement data and the system model prediction information, gradually reduce the covariance of the state estimation error, and thus obtain a more accurate and smooth piston rod 4 position estimate. The precise piston rod 4 position data processed by the Kalman filter is transmitted to the PLC control system. Based on these reliable data, the PLC control system adjusts the displacement of the main oil pump 1 of the filling industrial pump according to the pre-set control strategy. For example, when the piston rod 4 position data after the Kalman filter shows that its movement speed is accelerated, the PLC control system 15 will increase the displacement of the main oil pump 1 accordingly to ensure that the pumping volume can meet the filling demand; on the contrary, when the piston rod 4 position data shows that it is approaching the reversing point or the movement speed is slowing down, the PLC control system will finely adjust the displacement of the main oil pump 1 to reduce the reversing shock, realize efficient, stable and precise control of the entire filling process, and improve the overall reliability and filling quality of the system.

[0061] When the movement speed of the piston rod 4 gradually decreases, the change speed of the displacement of the main oil pump 1 also gradually decreases, so that the acceleration of the piston rod 4 gradually decreases, thereby further reducing the impact force.

[0062] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A full-stroke detection cylinder for filling an industrial pump, characterized in that: It includes an oil pump, a cylinder, a piston, a piston rod, a sealing assembly, a guide assembly, a guide sleeve, a Hall magnetic position sensor and a PLC control system. The cylinder has a liquid inlet, a liquid outlet and a sensor wiring port. The piston is slidably connected to the cylinder. The sealing assembly and the guide assembly are both arranged on the piston. The guide sleeve is installed on the cylinder. One end of the piston rod passes through the guide sleeve and is connected to the piston through the sealing assembly. The Hall magnetic position sensor is connected to the piston rod. The oil pump is connected to the liquid inlet. The Hall magnetic position sensor is connected to the sensor signal input end through the sensor wiring port. The PLC control system is connected to the sensor wiring port. The piston has a built-in throttle valve for controlling the volume. The Hall magnetic position sensor is used for stroke detection and reducing impact.

2. The full-stroke detection cylinder for filling industrial pumps according to claim 1, characterized in that: The Hall magnetic position sensor includes a Hall magnetic element and a magnetic float. The Hall magnetic element adopts an adaptive magnetic float floating structure. The Hall magnetic element is connected to the cylinder barrel. The magnetic float is arranged outside the Hall magnetic element and the magnetic float is built into the hollow structure of the piston rod.

3. The full-stroke detection cylinder for filling industrial pumps according to claim 1, characterized in that: The sealing assembly includes at least two sealing rings, and both of the sealing rings are in contact with the piston and the piston rod.

4. The full-stroke detection cylinder for filling industrial pumps according to claim 1, characterized in that: The guide assembly includes at least two guide rings, and the guide rings are both connected to the piston and the cylinder.

5. The full-stroke detection cylinder for filling industrial pumps as claimed in claim 2, characterized in that: The full-stroke detection oil cylinder for filling industrial pumps further comprises an annular seal, and the annular seal is arranged on the piston.

6. A control method for a full-stroke detection cylinder for filling an industrial pump, applied to the full-stroke detection cylinder for filling an industrial pump as claimed in claim 1, characterized in that: The steps include: Firstly, the sensor signal input end monitors the piston rod running position data in real time through the Hall magnetic position sensor; Afterwards, the monitored data is transmitted to the PLC control system; Subsequently, the PLC control system adjusts the displacement of the oil pump; Finally, the displacement is controlled by monitoring the piston position in real time.

7. The control method for the full stroke detection cylinder for filling industrial pumps according to claim 6, characterized in that: When monitoring the piston rod operating position data, piston kinematics control and volume adjustment based on Kalman filter algorithm are adopted.

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