A pipe cutting machine follow-up support mechanism and control method

Abstract

The present invention relates to the technical field of follow-up control of pipe cutting machines, and in particular to a follow-up support mechanism and control method for pipe cutting machines. The system comprises a servo motor, a lead screw, and a plurality of follow-up mechanisms for supporting pipe fittings, mounted on a frame of the pipe cutting machine. The servo motor drives the lead screw connected thereto to push the plurality of follow-up mechanisms to perform lifting movements. A linear telescopic mechanism is further mounted below the follow-up mechanism, wherein the top end of the linear telescopic mechanism is hinged to the upper portion of the follow-up mechanism. The support mechanism of the present invention can synchronously control the lifting and lowering of multiple follow-up arms, and can also individually control one or more follow-up arms, thereby ensuring that the pipe fitting is always in a stable and precise support state during the cutting process, effectively reducing cutting errors caused by shaking or displacement of the pipe fitting, and greatly improving cutting accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of follow-up control of a pipe cutting machine, and in particular to a follow-up support mechanism and a control method for a pipe cutting machine. Background Art

[0002] When cutting long profiles, laser tube cutting machines often incorporate support devices at appropriate locations within the machine to prevent deformation and sagging due to the profile's own weight. The main functions of these support mechanisms include improving cutting accuracy and stability, extending machine life, and improving operator working conditions. These machines typically incorporate multiple support mechanisms, each with its own servo drive mechanism, resulting in high costs.

[0003] In the field of pipe processing, traditional pipe cutting machine support mechanisms often have many limitations. As industrial manufacturing develops towards high precision, high efficiency and diversification, higher requirements are placed on the quality and adaptability of pipe cutting. Most of the previous pipe cutting machine support methods were relatively fixed, making it difficult to flexibly respond to the processing needs of pipes of different diameters and shapes. For example, the follow-up support device of the laser pipe cutting machine with patent application number 202321446878.9 cannot independently control the lifting mechanism during the support process, and cannot be accurately adjusted in real time according to the position changes of the pipes. As a result, the pipes are prone to shaking, offset and other unstable conditions during cutting, which seriously affects the cutting accuracy and is difficult to meet the strict standards for high-precision processing of pipes in industries such as precision instrument manufacturing and high-end pipeline installation.

[0004] At the same time, the existing supporting device usually adopts multiple cylinders and multiple rollers, and uses the cylinder to lift the roller to support the profile, which is costly and has different wear between the multiple cylinders during use, resulting in the inability to ensure the consistency of the profile support height in the later stage. At the same time, when the profile encounters an obstacle and needs to be lifted or rotated, it is necessary to first control the cylinder to descend, and then control the chuck rotation mechanism in the pipe cutting machine to drive the chuck to drive the profile to rotate. After the rotation is completed, the cylinder is controlled to drive the roller to rise to support the profile. It cannot follow the rotation of the profile for follow-up support, which affects the support effect and prolongs the processing time of the profile.

[0005] Therefore, there is an urgent need for a new type of pipe cutting machine follow-up support mechanism control system and method that can balance the cylinder pressure and coordinate the transportation of profile pipes. Summary of the Invention

[0006] In order to solve the above-mentioned problems, the present invention provides a follow-up support mechanism and a control method for a pipe cutting machine.

[0007] In a first aspect, the present invention provides a follow-up support mechanism and control method for a pipe cutting machine, which adopts the following technical solutions:

[0008] A follow-up support mechanism for a pipe cutting machine comprises: a servo motor mounted on a frame of the pipe cutting machine, a lead screw, and several follow-up mechanisms for supporting pipe fittings, wherein the servo motor drives the connected lead screw to push the several follow-up mechanisms to perform lifting movements, and a linear telescopic mechanism is further mounted below the follow-up mechanism, wherein the top of the linear telescopic mechanism is hinged to the upper part of the follow-up mechanism, and the bottom ends of the follow-up mechanism and the linear telescopic mechanism are respectively hinged to the frame of the pipe cutting machine, and the linear telescopic mechanism and the servo motor are respectively communicated with a controller and cooperate with each other to jointly control the lifting and lowering of the follow-up mechanism.

[0009] Furthermore, the follower mechanism includes a follower arm and a follower frame, the bottom end of the follower arm is hinged to the bottom of the frame of the pipe cutting machine through a base, the top end of the follower arm is installed with a clamping mechanism, the upper end of the follower frame is fixedly connected to the middle position of the follower arm, and the lower end of the follower frame is installed with a roller.

[0010] Furthermore, the lead screw is installed on the frame at the bottom of the pipe cutting machine, the input end of the lead screw is connected to the output end of the servo motor, and lead screw nuts are installed on the outer side of the lead screw at positions corresponding to several follower arms along the length direction. The lead screw nut moves linearly along the lead screw when the lead screw rotates, and a wedge block is fixedly connected to the outer side of the lead screw nut. The upper surface of the wedge block is rollingly connected to the roller at the lower end of the follower frame, and the wedge block is installed on the guide rail of the pipe cutting machine frame and is slidingly connected to the guide rail.

[0011] Furthermore, the side of the wedge block is connected to the screw nut and is driven to slide on the guide rail by the screw nut. When the roller at the lower end of the follower frame contacts different positions on the upper surface of the wedge block, the elevation of the upper end of the follower arm is different.

[0012] Furthermore, the linear telescopic mechanism is a pneumatic cylinder or a hydraulic cylinder, wherein the linear telescopic mechanism includes a piston rod and a cylinder barrel, a support is installed at the bottom of the cylinder barrel, the cylinder barrel is hinged to the support, and the support is fixed on the frame.

[0013] Furthermore, the linear telescopic mechanism is provided with a displacement sensor, and the output analog signal of the displacement sensor is output to the analog input port of the controller through a shielded cable.

[0014] Furthermore, the clamping mechanism adopts an adjustable clamping claw structure to adapt to pipes of different diameters, and the inner side of the clamping claw structure is equipped with a rubber pad to prevent damage to the surface of the pipe during the clamping process.

[0015] In a second aspect, a control method for a follow-up support mechanism of a pipe cutting machine is provided, which is used to control a follow-up support mechanism of a pipe cutting machine, comprising:

[0016] When controlling the synchronous lifting of multiple follower arms, the controller controls the speed and direction of the servo motor to rotate the lead screw and drive the lead screw nut to move. The lead screw nut drives the follower frame above the wedge block to make the follower arms move synchronously. At this time, the pressure in the cylinder of each linear telescopic mechanism is not enough to independently support the follower arm.

[0017] When one or more follower arms are controlled individually, the controller controls the pressure in the cylinder to extend and retract the piston rod, and the piston rod is used to support each follower arm to perform independent lifting motion.

[0018] The controller coordinates the screw speed and cylinder air pressure to control the lifting and lowering movement of the partial follower arm.

[0019] Furthermore, the controller collaboratively controls the screw speed and cylinder air pressure to control part of the follower arm to perform lifting and lowering movements, including calculating the PID control parameters based on the signal parameters obtained by the displacement sensor on the pneumatic rod according to the deviation between the target position and the current position of the follower arm, and calculating the speed and rotation direction of the servo motor based on the integral term, differential term and proportional term in the PID control parameters.

[0020] Furthermore, the controller collaboratively controls the screw speed and the cylinder air pressure to control the lifting and lowering movement of part of the follower arm, and also includes calculating the PID control parameters based on the signal parameters obtained by the displacement sensor on the pneumatic rod according to the deviation between the current support force of the pneumatic rod and the target support force, calculating the command value of the cylinder electromagnetic proportional valve based on the integral term, differential term and proportional term in the PID control parameters, and adjusting the opening degree of the electromagnetic proportional valve according to the command value to control the air pressure in the cylinder.

[0021] In summary, the present invention has the following beneficial technical effects:

[0022] The present invention coordinates the servo motor speed and cylinder pressure to precisely control the lifting and lowering motion of the follower arm, ensuring that the pipe is always in a stable and precise support state during the cutting process, effectively reducing cutting errors caused by pipe shaking or displacement, greatly improving cutting accuracy, and meeting industrial production needs with high requirements for pipe processing accuracy, including the processing of high-precision pipes in fields such as aerospace, automobile manufacturing, etc.

[0023] The present invention's dynamic support mechanism quickly and accurately responds to changes in the pipe's position during cutting, achieving dynamic support and reducing pauses and adjustment time during the cutting process. Furthermore, the stable support helps extend the life of the cutting tool and improve cutting efficiency, thereby improving the overall production efficiency of the pipe cutting machine, reducing production costs, and enhancing the company's market competitiveness.

[0024] This invention combines a linear telescopic mechanism with a lead screw drive and utilizes a PID control algorithm to ensure stable operation of the follower support mechanism under various operating conditions, reducing the probability of failures caused by external interference or internal component wear. This reliable operation ensures the continuity and stability of the production process, reduces equipment maintenance costs and production downtime, and improves production efficiency.

[0025] This invention achieves automated control of the follower support mechanism by acquiring signals through sensors and using a controller for data processing and command transmission. The operator simply sets relevant parameters in the control system, such as pipe size and cutting path, and the equipment automatically completes the support and cutting process, reducing operator skill requirements and labor intensity while improving production standardization and consistency.

[0026] The present invention's adjustable jaw structure and independently controllable follower support mechanism easily adapt to pipes of varying diameters, materials, and shapes. Whether it's small-diameter precision pipes or large-diameter industrial pipelines, this system provides stable support and efficient cutting, broadening the pipe cutter's application range and reducing the cost and time required to replace equipment or tooling due to changes in pipe specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of a pipe cutting machine with a follow-up support mechanism according to an embodiment of the present invention.

[0028] Figure 2 It is a schematic diagram of a follow-up support mechanism for a pipe cutting machine according to an embodiment of the present invention.

[0029] Figure 3 This is another structural schematic diagram of a follow-up support mechanism for a pipe cutting machine according to an embodiment of the present invention.

[0030] Figure 4 Schematic diagram of a clamping mechanism according to an embodiment of the present invention.

[0031] Figure 5 2 is another overall structural diagram of the pipe cutting machine according to an embodiment of the present invention.

[0032] Figure 6 It is a partial schematic diagram of a wedge block according to an embodiment of the present invention.

[0033] Figure 7 It is a schematic diagram of a control method of a follow-up support mechanism of a pipe cutting machine according to an embodiment of the present invention.

[0034] Among them, 1. follower arm; 2. linear telescopic mechanism; 3. servo motor; 4. lead screw; 5. pipe fitting; 6. clamping mechanism; 7. follower frame; 8. lead screw nut; 9. wedge block; 10. clamping seat 1; 11. clamping seat 2; 12. slide rail; 13. support roller; 14. support; 15. support frame; 16. roller; 17. guide rail. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings.

[0036] Example 1

[0037] Reference Figure 1 A follow-up support mechanism for a pipe cutting machine in this embodiment includes: a servo motor 3 installed on a pipe cutting machine frame, a lead screw 4, and several follow-up mechanisms for supporting pipe fittings 5, wherein the servo motor 3 drives the connected lead screw 4 to push the several follow-up mechanisms to perform lifting movements, and a linear telescopic mechanism 2 is also installed below the follow-up mechanism, wherein the top of the linear telescopic mechanism 2 is hinged to the upper part of the follow-up mechanism, and the bottom ends of the follow-up mechanism and the linear telescopic mechanism 2 are respectively hinged to the pipe cutting machine frame, and the linear telescopic mechanism 2 and the lead screw 4 cooperate with each other to jointly control the lifting and lowering of the follow-up mechanism.

[0038] like Figure 2 and Figure 3 As shown, the follower mechanism includes a follower arm 1 and a follower frame 7. The follower arm 1 is connected to the linear telescopic mechanism 2, with the bottom end of the follower arm 1 hingedly connected to the base and fixed to the bottom of the pipe cutting machine frame. The top of the follower arm 1 is connected to a clamping mechanism 6 for clamping the pipe 5. The upper end of the follower frame 7 is fixedly connected to the middle position of the follower arm 1. The lower end of the follower frame 7 is mounted with a roller 16, which is in rolling connection with a wedge block 9. The interaction between the roller 16 and the wedge block 9 limits the position of the follower arm 1 during its raising and lowering. A lead screw 4 is mounted on the frame at the bottom of the pipe cutting machine. The lead screw 4 is connected to a servo motor. Lead screw nuts 8 are installed on the outside of the lead screw 4 at positions corresponding to the follower arm 1 along its length. The lead screw nuts 8 cooperate with the lead screw 4 for linear motion. The outer edge of the screw nut 8 is fixedly connected to the wedge block 9 near the side of the follower arm 1. The screw nut 8 is driven by the rotation of the screw 4, so that the wedge block 9 is subjected to force to drive the follower arm 1 to move up and down.

[0039] like Figure 2 and Figure 3As shown, in this embodiment, the linear telescopic mechanism 2 is a pneumatic cylinder comprising a cylinder barrel and a piston rod. A cylinder support is provided at the bottom of the cylinder barrel, articulated to the cylinder barrel support, and secured to the frame. The cylinder is equipped with a displacement sensor, a linear Hall effect sensor connected to a controller. The output analog signal of the displacement sensor is transmitted to the analog input port of the controller via a shielded cable. The clamping mechanism 6 utilizes an adjustable jaw structure to accommodate pipes 5 of varying diameters. A rubber pad is installed on the inside of the jaw structure to prevent damage to the surface of the pipe 5 during clamping.

[0040] Specifically,

[0041] The follower mechanism of this embodiment is made of high-strength alloy steel, ensuring sufficient load-bearing capacity and stability to support pipes 5 of various specifications. The follower arm 1 is designed as a box-shaped structure with internal reinforcement ribs to reduce its own weight while enhancing its bending and torsional resistance. Its bottom end is connected to the base via a machined hinge seat, which is bolted to the thickened mounting plate at the bottom of the pipe cutting machine frame to ensure a secure and reliable connection. The clamping mechanism 6 is mounted on the top of the follower arm 1 and adopts an adjustable clamping jaw design that can adapt to pipes 5 of different diameters. It is equipped with a rubber pad to prevent damage to the surface of the pipe 5 during the clamping process. The connection between the cylinder and the top of the follower arm 1 adopts an articulated structure. The self-lubricating spherical bearing reduces friction resistance and ensures smooth and stable lifting and lowering movement of the follower arm 1. The cylinder is driven by a high-precision, highly sealed cylinder barrel, which has excellent linear expansion and contraction performance and fast response capabilities. Its operating pressure can be adjusted according to the weight of the pipe 5 and the processing conditions.

[0042] like Figure 3 As shown, the follower frame 7 of this embodiment is made of aluminum alloy and is fixedly connected to the middle of the follower arm 1. The roller 16 at the bottom of the follower frame 7 forms rolling contact with the wedge block 9. The wedge block 9 is surface-hardened to improve its wear resistance and hardness. Its shape and angles are optimized to accurately limit the follower arm 1 during its raising and lowering, preventing it from excessive swing or deviation, ensuring accurate and stable support, and reducing vibration and noise during the movement of the follower arm 1.

[0043] like Figure 6As shown, the lead screw 4 in this embodiment utilizes a trapezoidal screw, offering high transmission efficiency and positioning accuracy. Its lead is selected based on the required travel and speed of the follower arm 1. Both ends of the lead screw 4 are mounted on the bearing seats of the bottom frame of the pipe cutter via angular contact ball bearings, ensuring the stability and rigidity of the lead screw 4 during high-speed rotation. The servo motor utilizes an AC servo motor, offering precise speed and position control capabilities. It is directly connected to the lead screw 4 via an elastic coupling, minimizing transmission errors and vibration. The lead screw nut 8 utilizes a double-nut preload structure, effectively eliminating backlash and ensuring the linear motion accuracy of the lead screw nut 8 on the lead screw 4.

[0044] The cylinder of this embodiment utilizes a rear-mounted earring installation method. The cylinder support is welded to the frame and undergoes an aging treatment to eliminate welding stress, ensuring the structural strength and stability of the cylinder support. Seals are used between the cylinder and the cylinder piston rod to prevent air leakage, ensuring the cylinder's operating performance and service life. Throttle valves and check valves are installed at the cylinder's inlet and outlet to regulate the air flow and pressure, enabling precise control of the cylinder's extension and retraction speed and maintaining pressure, thereby meeting the support force and movement speed requirements of the follower arm 1 under different operating conditions.

[0045] The displacement sensors on the cylinder of this embodiment all use linear Hall sensors, which have the advantages of high measurement accuracy, fast response speed, and strong anti-interference ability. The sensor housing is made of stainless steel and has good protection performance. It can adapt to the harsh conditions such as oil, dust and cutting fluid in the working environment of the pipe cutting machine. The shielded cable adopts a double-layer shielding structure to effectively reduce the impact of external electromagnetic interference on the sensor signal and ensure the stability and accuracy of signal transmission. The controller adopts a programmable logic controller (PLC), which has powerful data processing capabilities and rich control algorithms. It can accurately control the speed and direction of the servo motor and the air pressure of the cylinder in real time according to the signal fed back by the displacement sensor, and realize the automation and intelligent control of the follow-up support mechanism. At the same time, the controller also has fault diagnosis and alarm functions, which can promptly detect and prompt abnormal conditions in the system to ensure the safe and stable operation of the equipment.

[0046] like Figure 4In the clamping mechanism shown, clamping base 10 and clamping base 2 11 are key components used to directly clamp the workpiece. They are arranged relative to each other to enable clamping of the workpiece from both sides. Clamping base 10 and clamping base 2 11 are connected. Clamping base 10 and clamping base 2 11 are mounted on a slide rail 12, allowing them to move linearly along the slide rail 12. The slide rail 12 serves as a guide, ensuring the accuracy and stability of the clamping base during movement. Support rollers 13 are used to reduce friction during movement of the clamping base, ensuring smoother movement. Support rollers 13 are mounted on the bottom of the clamping base, supporting and assisting its movement through rolling contact. Support base 14 supports the entire clamping mechanism. Connected to support frame 15, it provides a stable foundation for the entire mechanism. When a workpiece needs to be clamped, clamping base 10 and clamping base 2 11 move toward each other along the slide rail 12 under the action of a driving force. Thanks to the guidance of the slide rail 12, the clamping base can accurately clamp the workpiece. The support roller 13 reduces resistance to the clamping base's movement during this process, making the clamping action faster and smoother. When the workpiece needs to be released, an external driving force acts in the opposite direction, causing clamping base 10 and clamping base 2 11 to move in opposite directions along the slide rail 12, thereby releasing the workpiece.

[0047] Example 2

[0048] The difference between this embodiment and embodiment 1 is that this embodiment provides a control method for a follower support mechanism of a pipe cutting machine, which is used to control a follower support mechanism of a pipe cutting machine, including: when controlling the synchronous lifting of multiple follower arms 1, the controller controls the speed and direction of the servo motor to rotate the screw 4 and drive the screw nut 8 to move, and the screw nut 8 drives the follower frame 7 above the wedge block 9 to make the follower arm 1 perform synchronous lifting and lowering movements; at this time, the pressure in the cylinder of each linear telescopic mechanism 2 is not enough to independently support the follower arm 1; when controlling one or some follower arms 1 separately, the controller controls the pressure in the cylinder to extend and retract the piston rod, and uses the piston rod to support each follower arm 1 to perform independent lifting and lowering movements; the controller coordinates the speed of the screw 4 and the cylinder air pressure to control some follower arms 1 to perform lifting and lowering movements. The controller coordinates the rotation speed of the lead screw 4 and the cylinder air pressure to control the lifting and lowering movement of the portion of the follower arm 1. This includes calculating PID control parameters based on the deviation between the target position and the current position of the follower arm 1 based on the signal parameters obtained by the displacement sensor on the cylinder, and calculating the rotation speed and rotation direction of the servo motor based on the integral, differential, and proportional terms in the PID control parameters. The controller coordinates the rotation speed of the lead screw 4 and the cylinder air pressure to control the lifting and lowering movement of the portion of the follower arm 1. This also includes calculating PID control parameters based on the deviation between the current support force of the cylinder and the target support force based on the signal parameters obtained by the displacement sensor on the cylinder, and calculating the command value of the cylinder electromagnetic proportional valve based on the integral, differential, and proportional terms in the PID control parameters. The opening degree of the electromagnetic proportional valve is adjusted by the command value to control the cylinder air pressure.

[0049] Specifically,

[0050] When the pipe cutter begins operation or the specifications of the pipe 5 change, the controller first calculates the initial synchronous lifting position required by the follower arm 1 based on the preset program and the parameter information of the pipe 5. It then sends the corresponding control instructions to the servo motor to drive the screw 4 to rotate. The servo motor uses a closed-loop control method, and the encoder installed on the motor shaft provides real-time feedback on the motor's speed and position. The controller uses this feedback information to precisely control the motor's speed and position, ensuring the rotation accuracy and stability of the screw 4. The rotation of the screw 4 drives the screw nut 8 to move linearly along the length of the screw. Under the coordinated action of the screw 4, multiple screw nuts 8 simultaneously push their corresponding wedge blocks 9 to move. Due to the limiting relationship between the wedge blocks 9 and the follower arm 1, the follower arm 1 achieves synchronous lifting and lowering motion under the action of the wedge blocks 9. During the entire synchronous lifting process, the controller continuously monitors the position information of the follower arm 1 fed back by the displacement sensor, compares it with the preset position, and adjusts the control instructions of the servo motor in real time according to the comparison result, to ensure that the follower arm 1 can quickly and accurately reach the predetermined synchronous lifting position, and maintain a stable support state during the processing process, adapting to operations such as the overall translation or rotation of the pipe 5.

[0051] During the processing of the pipe fitting 5, if it is necessary to independently control the lifting and lowering motion of a single or multiple follower arms 1, the controller monitors the actual position and force state of each follower arm 1 in real time based on the information fed back by the displacement sensor installed on the cylinder. When it is detected that a follower arm 1 needs to be adjusted, the controller calculates the required lifting amount and air pressure change value of the follower arm 1 according to the preset control algorithm and process requirements, and sends a control instruction to the corresponding cylinder to adjust the air intake and return air flow of the cylinder, thereby accurately controlling the extension and contraction of the cylinder. During the extension and contraction of the cylinder, the follower arm 1 realizes independent lifting and lowering motion to adapt to the special local conditions of the pipe fitting 5, ensuring that the pipe fitting 5 always receives stable and reliable support during the processing process. At the same time, the controller will also dynamically adjust the position and support force of other follower arms 1 to maintain the balance and stability of the entire support system and avoid affecting other parts due to the adjustment of a single follower arm 1. In addition, in order to improve the response speed and control accuracy of the independent lifting movement, the controller adopts a predictive control algorithm adjustment strategy. It can predict the movement trend and force requirements of the follower arm 1 in advance according to the real-time changes in the pipe 5 during the processing, and adjust the control parameters in time to achieve efficient and precise control of the follower support mechanism, further improving the processing quality and production efficiency of the pipe cutting machine.

[0052] The displacement sensor mounted on the cylinder obtains the analog signal voltage value of the follower arm's current position. The voltage signal output by the displacement sensor on the cylinder is V1. The sensor's calibration coefficient is used to convert the analog signal into an actual displacement value. Assuming the calibration coefficient of the displacement sensor on the cylinder is K1 (unit: meter / volt), the corresponding current position X1 (unit: meter) on the cylinder and the current position X2 (unit: meter) of the wedge block are calculated using the following formula:

[0053] x1=V1×k1;

[0054] x2=V2×k2.

[0055] At the same time, a pressure sensor is installed on the follower arm 1 to measure the key support force required for the follower arm 1. The obtained sensor output signal voltage value is VF, which is converted into the actual support force value F (unit: Newton) through the calibration coefficient KF (unit: Newton / volt) of the force sensor. The calculation formula is: F = V F ×k F .

[0056] Receive parameters related to the current pipe 5 processing process from the pipe cutting machine control system, such as the current cutting position coordinates (xc, yc) of the pipe 5 (unit: meter), the cutting speed vc (unit: meter / second), and the target size of the pipe 5 including the pipe diameter and wall thickness information. These parameters serve as an important basis for subsequent motion planning.

[0057] First, the target position of the follower arm 1 is calculated. Based on process parameters such as the current cutting position, cutting speed, and target size of the pipe 5, and in combination with the geometric relationship between the follower arm 1 and the pipe 5, a geometric calculation model is used to determine the target position that the follower arm 1 should reach during the current processing phase. Based on the assumption of a linear cutting path for the pipe 5, the target horizontal position Xt (in meters) and vertical position Yt (in meters) of the follower arm 1 are calculated based on the distance relationship between the cutting position and the follower arm 1 and the preset support spacing requirements. For synchronized lifting motion, the target vertical position Yt is the same for all follower arms 1, and the target horizontal position Xt is determined based on the overall horizontal movement of the pipe 5. For independent lifting motion, when local shape changes of the pipe 5 are detected, a specific target vertical position Yt is calculated for each affected follower arm 1 through more detailed local geometric analysis and mechanical modeling (taking into account factors such as the local curvature and wall thickness variations of the pipe 5). The horizontal position Xt remains unchanged or is adjusted accordingly based on the overall processing conditions.

[0058] Then, based on the material, size, and cutting process requirements of the pipe 5, a mechanical analysis model is used to calculate the target support force Ft (unit: Newton) required by the follower arm. Taking into account factors such as the pipe 5's own weight during cutting and the bending moment caused by the cutting force, the target support force Ft is calculated based on beam theory in material mechanics (if the pipe 5 is approximately treated as a beam structure) or a simplified finite element analysis model (for more complex pipe 5 shapes and stress conditions).

[0059] The PID control algorithm is used to control the servo motor speed. First, the horizontal and vertical deviations between the current position of the follower arm 1 and the target position are calculated. Assuming the horizontal position deviation is ex (unit: meter) and the vertical position deviation is ey (unit: meter), the calculation formula is as follows:

[0060]

[0061] Predetermine the proportional coefficient Kp, integral coefficient Ki and differential coefficient Kd of the PID control algorithm, and calculate the proportional term P, integral term I and differential term D of the PID control. The proportional term is directly proportional to the position deviation, and the calculation formula is: P = K P ×e x , (for horizontal direction control); P = K P ×e y (For vertical control).

[0062] Using the discretization method, the integral calculation is performed every fixed time interval, which can be expressed as: (For horizontal direction control, n is the current sampling number); (For vertical control).

[0063] The differential term responds to the rate of change of the position deviation and uses a discretization method to approximately calculate the rate of change of the deviation as: (For horizontal direction control, n and n-1 represent the current and previous sampling moments respectively); (For vertical control).

[0064] Finally, the speed command of the servo motor is expressed as:

[0065] Add the proportional, integral, and differential terms of the PID control to obtain the speed control command values ​​(unit: revolutions per minute, rpm) for the servo motor in the horizontal and vertical directions. Assume that the horizontal speed command is nx and the vertical speed command is ny. The calculation formula is:

[0066] n x =P+I+D;

[0067] n y =P+I+D.

[0068] The cylinder air pressure control also uses the PID control algorithm, which calculates the support force deviation and PID control parameters based on the pressure closed loop, and finally calculates the electromagnetic proportional valve control instruction. Among them, the deviation ΔF (unit: Newton) between the current support force and the target support force is calculated.

[0069] Determine the proportional coefficient Kp', integral coefficient Ki' and differential coefficient Kd' of the PID control algorithm used for cylinder air pressure control (also need to be optimized according to the characteristics of the air pressure system and actual debugging).

[0070] The proportional term P', integral term I' and differential term D' of the air pressure control are calculated in a similar way to the servo motor speed control. The proportional term is: P' = K P ′×ΔF;

[0071] The integral term is:

[0072] The differential term is:

[0073] Finally, calculate the electromagnetic proportional valve control command: add the proportional term, integral term and differential term of the air pressure control to get the current control command value I of the electromagnetic proportional valve. valve (Unit: Ampere), this instruction is used to adjust the opening of the electromagnetic proportional valve, thereby controlling the air pressure in the cylinder. The calculation formula is: I valve =P′+I′+D′.

[0074] Example 3

[0075] During the processing of pipe 5, if the pipe 5 exhibits local irregularities in shape or changes in cutting position, certain follower arms 1 may need to be individually controlled to ensure stable support. For example, when processing a pipe with a unique shape, a section of the pipe 5 may bend locally, requiring independent lifting and lowering adjustments of certain follower arms 1. First, a displacement sensor mounted on the cylinder acquires the current position of the follower arms 1 in real time and feeds the signal back to the controller.

[0076] Assume that a certain follower arm 1 is A. When follower arm A needs to be adjusted, the voltage signal output by the displacement sensor on the cylinder is V1A, and the voltage signal output by the displacement sensor is V2A. The analog signal is converted into the actual displacement value using the calibration coefficient of the sensor. Assume that the calibration coefficient of the displacement sensor on the cylinder is K1 (unit: meter / volt). Then the current position X1A (unit: meter) of the cylinder and the current position X2A (unit: meter) of the wedge block are calculated by the following formula: X 1A =V 1A ×K1;X 2A =V 2A ×K2.

[0077] At the same time, the pressure sensor installed on the top of the follower arm 1 measures the supporting force on the pipe 5. The obtained sensor output signal voltage value is VFA, which is converted into the actual supporting force value FA (unit: Newton) through the calibration coefficient KF (unit: Newton / volt) of the force sensor. The calculation formula is: F A =V FA ×K F .

[0078] The controller receives parameters related to the current pipe processing process from the pipe cutting machine control system, such as the current cutting position coordinates (Xc, Yc) of pipe 5 (units: meters), the cutting speed Vc (units: meters / second), and the target dimensions of pipe 5, including diameter and wall thickness. Based on these parameters, the preset control algorithm and process requirements, and the geometry of the local bend of pipe 5, a geometric calculation model is used to determine the target position that follower arm A should reach during the current processing phase, including the target horizontal position XtA (units: meters) and the target vertical position YtA (units: meters). Simultaneously, a mechanical analysis model is used to calculate the target support force FtA (units: Newtons) required by follower arm A, based on the pipe material, dimensions, and cutting process requirements.

[0079] Let follower arm 1 be A. Calculate the horizontal and vertical deviations between the current position of follower arm A and the target position. Let the horizontal deviation be exA (unit: meter) and the vertical deviation be eyA (unit: meter). The calculation formulas are as follows:

[0080] Predetermine the proportional coefficient Kp', integral coefficient Ki', and differential coefficient Kd' of the PID control algorithm for cylinder air pressure control. Calculate the proportional term P', integral term I', and differential term D' of the PID control. The proportional term is: P' = K' p ×e yA ; Using the discretization method, an integral calculation is performed every fixed time interval, which can be expressed as: (n is the current sampling number); the differential term responds to the rate of change of the position deviation, and the discretization method is used to approximately calculate the rate of change of the deviation as follows:

[0081] (n and n-1 represent the current and previous sampling moments respectively).

[0082] Finally, the proportional term, integral term and differential term of PID control are added together to obtain the current control command value I of the electromagnetic proportional valve. valveA (Unit: Ampere), this instruction is used to adjust the opening of the electromagnetic proportional valve, thereby controlling the air pressure in the cylinder. The calculation formula is: I valveA =P′+I′+D′. By adjusting the air pressure in the cylinder, the piston rod is extended and retracted, thereby driving the follower arm A to independently move up and down to adapt to the special conditions of the pipe 5 and ensure that the pipe 5 is always stably and reliably supported during the processing.

[0083] The linear telescopic mechanism 2 , such as a cylinder, comprises a piston rod and a cylinder barrel, a support is mounted on the bottom of the cylinder barrel, the cylinder barrel and the support are hinged, and the support is fixed to the frame. The top of the linear telescopic mechanism 2 is hinged to the upper part of the follower arm 1 .

[0084] When the piston rod is extended or retracted, the follower arm 1 will rotate around the hinge point between its bottom end and the frame. For example, when the piston rod is extended, the follower arm 1 will lift upward, and the angle between the linear telescopic mechanism 2 and the frame will gradually increase. Assuming that the initial length of the piston rod is L0, the length of the follower arm is l, and the distance from the hinge point between the bottom end of the follower arm 1 and the top of the linear telescopic mechanism 2 to the hinge point between the bottom end of the follower arm and the frame is d, when the piston rod is not extended, the angle between the linear telescopic mechanism 2 and the frame is, according to the trigonometric function relationship (h0 is the vertical distance from the top of the linear telescopic mechanism 2 to the frame at this time).

[0085] When the piston rod is extended to a length of ΔL, the new length is L1=L0+ΔL. At this time, the angle between the linear telescopic mechanism 2 and the frame changes. According to the trigonometric function relationship As the follower arm rises, h1 and L1 increase. However, the change in h1 and L1 is not linear, so the angle varies accordingly with the extended length of the piston rod. In practice, a displacement sensor monitors the piston rod's extension length in real time. Combined with the geometric parameters and installation position of follower arm A, the controller accurately calculates the change in the angle of the linear telescopic mechanism 2, enabling more precise control of the follower arm A's lifting and lowering motion.

[0086] The above are all preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A follow-up support mechanism for a pipe cutting machine, characterized in that: include: A servo motor, a lead screw, and several follower mechanisms for supporting pipe fittings are installed on the pipe cutting machine frame, wherein the servo motor drives the lead screw to push the several follower mechanisms to perform lifting movements, and a linear telescopic mechanism is also installed below the follower mechanism, wherein the top of the linear telescopic mechanism is hinged to the upper part of the follower mechanism, and the bottom ends of the follower mechanism and the linear telescopic mechanism are respectively hinged to the pipe cutting machine frame, and the linear telescopic mechanism and servo motor are respectively communicated with the controller and cooperate with each other to jointly control the lifting and lowering of the follower mechanism; the linear telescopic mechanism includes a piston rod and a cylinder; The follower mechanism includes a follower arm and a follower frame. The bottom end of the follower arm is hinged to the bottom of the frame of the pipe cutting machine through a base. The top end of the follower arm is equipped with a clamping mechanism. The upper end of the follower frame is fixedly connected to the middle position of the follower arm. The lower end of the follower frame is equipped with a roller. The lead screw is mounted on a frame at the bottom of the pipe cutting machine, the input end of the lead screw is connected to the output end of the servo motor, and lead screw nuts are mounted on the outer side of the lead screw at positions corresponding to a plurality of follower arms along the length direction. The lead screw nut is rotated by the lead screw to perform linear motion along the lead screw, and a wedge block is fixedly connected to the outer side of the lead screw nut. The upper surface of the wedge block is in rolling connection with the roller at the lower end of the follower frame, and the wedge block is mounted on the guide rail of the pipe cutting machine frame and is in sliding connection with the guide rail. The side surface of the wedge block is connected to the screw nut and is driven by the screw nut to slide on the guide rail. When the roller at the lower end of the follower frame contacts different positions of the upper surface of the wedge block, the elevation of the upper end of the follower arm is different. The controller coordinates the screw speed and the pressure in the cylinder to control the lifting and lowering movement of part of the follower arm, including the signal parameters obtained by the displacement sensor based on the linear telescopic mechanism, the PID control parameters are calculated according to the deviation between the target position and the current position of the follower arm, and the speed and rotation direction of the servo motor are calculated based on the integral term, differential term and proportional term in the PID control parameters.

2. A follow-up support mechanism for a pipe cutting machine according to claim 1, characterized in that: The linear telescopic mechanism is a pneumatic cylinder or a hydraulic cylinder, wherein a support is installed at the bottom of the cylinder barrel, the cylinder barrel is hinged to the support, and the support is fixed on the frame.

3. A follow-up support mechanism for a pipe cutting machine according to claim 2, characterized in that: The linear telescopic mechanism is provided with a displacement sensor, and an output analog signal of the displacement sensor is output to an analog input port of a controller via a shielded cable.

4. A follow-up support mechanism for a pipe cutting machine according to claim 3, characterized in that: The clamping mechanism adopts an adjustable clamping claw structure to adapt to pipes of different diameters. The inner side of the clamping claw structure is equipped with a rubber pad to prevent damage to the surface of the pipe during the clamping process.

5. A control method for a follow-up support mechanism of a pipe cutting machine, characterized in that: Controlling a follow-up support mechanism for a pipe cutting machine according to any one of claims 1 to 4, comprising: When controlling the synchronous lifting of multiple follower arms, the controller controls the speed and direction of the servo motor to rotate the lead screw and drive the lead screw nut to move. The lead screw nut drives the follower frame above the wedge block to make the follower arms move synchronously. At this time, the pressure in the cylinder of each linear telescopic mechanism is not enough to independently support the follower arm. When one or more follower arms are controlled individually, the controller controls the pressure in the cylinder to extend and retract the piston rod, and the piston rod is used to support each follower arm to perform independent lifting motion. The controller coordinates the screw speed and the pressure in the cylinder to control the lifting and lowering movement of the boom.

6. The control method of the follow-up support mechanism of a pipe cutting machine according to claim 5, characterized in that: The controller is used to coordinately control the screw speed and the pressure in the cylinder to control the lifting movement of part of the follower arm. It also includes calculating PID control parameters based on the signal parameters obtained by the displacement sensor on the linear telescopic mechanism according to the deviation between the current support force and the target support force of the linear telescopic mechanism, calculating the command value of the cylinder electromagnetic proportional valve based on the integral term, differential term and proportional term in the PID control parameters, and adjusting the opening degree of the electromagnetic proportional valve according to the command value to control the pressure in the cylinder.

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