Pipe cutting machine follow-up supporting mechanism and control method

Abstract

The invention relates to the technical field of pipe cutting machine follow-up control, in particular to a pipe cutting machine follow-up supporting mechanism and a control method. The system comprises a servo motor, a lead screw and a plurality of follow-up mechanisms, the servo motor, the lead screw and the follow-up mechanisms are mounted on a pipe cutting machine frame, the follow-up mechanisms are used for supporting pipe fittings, the servo motor pushes the follow-up mechanisms to ascend and descend through the lead screw which is in driving connection with the servo motor, and linear telescopic mechanisms are further mounted below the follow-up mechanisms. Wherein the top end of the linear telescopic mechanism is hinged to the upper portion of the follow-up mechanism, through the supporting mechanism, lifting control can be synchronously conducted on a plurality of follow-up arms, one or some follow-up arms can be independently controlled, it is guaranteed that a pipe fitting is always in a stable and accurate supporting state in the cutting process, and therefore the pipe fitting can be cut more stably and accurately. Cutting errors caused by shaking or displacement of the pipe fitting are effectively reduced, and the cutting precision is greatly improved.

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 profiles, some profiles are relatively long. In order to prevent the profiles from sagging and deforming due to their own weight, a support device is often set at an appropriate position in the laser tube cutting machine to support the profiles. The main functions of the follow-up support of the tube cutting machine include improving cutting accuracy and stability, extending the service life of the machine, and improving the working conditions of the operator. The tube cutting machine contains multiple follow-up support mechanisms, each of which contains a set of servo drive mechanisms, which are relatively expensive.

[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 support methods for pipe cutting machines 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 individually control the lifting mechanism during the support process, and cannot be accurately adjusted in real time according to the position changes of the pipes, resulting in the pipes being prone to shaking, offsetting 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 control system and method for the follow-up support mechanism of a pipe cutting machine 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 the 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 installed on a frame of the pipe cutting machine, a lead screw and a plurality of follow-up mechanisms for supporting pipe fittings, wherein the servo motor drives the lead screw to push the plurality of follow-up mechanisms to perform lifting movements, a linear telescopic mechanism is also installed below the follow-up mechanism, wherein the top of the linear telescopic mechanism is hinged to the upper part of the follow-up mechanism, 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 to 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, a clamping mechanism is installed at the top of the follower arm, the upper end of the follower frame is fixedly connected to the middle position of the follower arm, and a roller is installed at the lower end of the follower frame.

[0010] Furthermore, the lead screw is installed 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 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 slidably connected to the guide rail.

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

[0012] Furthermore, the linear telescopic mechanism is a pneumatic cylinder or a hydraulic cylinder, wherein the linear telescopic mechanism comprises 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 an output analog signal of the displacement sensor is output to an analog input port of the controller via a shielded cable.

[0014] Furthermore, the clamping mechanism adopts an adjustable clamping jaw structure to adapt to pipes of different diameters, and the inner side of the clamping jaw 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 multiple follower arms to rise and fall synchronously, the controller controls the speed and direction of the servo motor to rotate the lead screw and drive the lead screw nut to move, and the lead screw nut drives the follower frame above the wedge block to make the follower arms rise and fall 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 some follower arms are controlled individually, the pressure in the cylinder is controlled by the controller to extend and retract the piston rod, and the piston rod is used to support each follower arm to perform independent lifting and lowering movements;

[0018] The controller coordinately controls the screw speed and the cylinder air pressure to control the lifting and lowering movement of part of the 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 PID control parameters based on 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 part of the follower arm to perform lifting and lowering movements, and also includes calculating PID control parameters based on signal parameters obtained by the displacement sensor on the pneumatic rod according to the deviation between the current supporting force of the pneumatic rod and the target supporting 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 by the command value, thereby controlling the air pressure in the cylinder.

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

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

[0023] The follow-up support mechanism of the present invention can quickly and accurately respond to the position change of the pipe during the cutting process, realize follow-up support, and reduce the pause and adjustment time during the cutting process. At the same time, the stable support state helps to improve the service life and cutting efficiency of the cutting tool, thereby improving the production efficiency of the entire pipe cutting machine, reducing production costs, and enhancing the competitiveness of the enterprise in the market.

[0024] The present invention adopts a design combining a linear telescopic mechanism with a lead screw drive and uses a PID control algorithm to enable the follow-up support mechanism to operate stably under various working conditions, reducing the probability of failures caused by external interference or wear of internal components. Reliable operating performance ensures the continuity and stability of the production process, reduces equipment maintenance costs and production downtime, and improves production efficiency.

[0025] The present invention obtains signals through sensors, processes data and sends instructions using controllers, and realizes automatic control of the follow-up support mechanism. The operator only needs to set relevant parameters in the control system, such as pipe size, cutting path, etc., and the equipment can automatically complete the support and cutting process, which reduces the skill requirements and labor intensity of the operator and improves the standardization and consistency of production.

[0026] The adjustable clamping jaw structure and independently controllable follow-up support mechanism of the present invention can easily adapt to pipes of different diameters, materials and shapes. Whether it is a small-diameter precision pipe or a large-diameter industrial pipe, stable support and efficient cutting can be achieved in this system, which broadens the application range of the pipe cutting machine and reduces the cost and time of replacing 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 of a pipe cutting machine 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 It 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 schematic 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 fittings; 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 is further described in detail below in conjunction with 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 frame of the pipe cutting machine, a lead screw 4, and a plurality of follow-up mechanisms for supporting pipe fittings 5, wherein the servo motor 3 drives the connected lead screw 4 to push the plurality of 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 frame of the pipe cutting machine, and the linear telescopic mechanism 2 and the lead screw 4 cooperate with each other to jointly control the lifting 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 a linear telescopic mechanism 2, wherein the bottom end of the follower arm 1 is hingedly connected to the bottom of the frame of the pipe cutting machine through a base. The top of the follower arm 1 is connected to a clamping mechanism 6 for clamping a pipe fitting 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 installed with a roller 16, which is rollingly connected to a wedge block 9. The follower arm 1 is limited in position during the lifting process of the follower arm 1 through the cooperation of the roller 16 and the wedge block 9. A lead screw 4 is installed 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 outer side of the lead screw 4 along the length direction at positions corresponding to the follower arm 1. The lead screw nuts 8 cooperate with the lead screw 4 and move linearly. The outer edge of the lead screw nut 8 is fixedly connected to the wedge block 9 near the follower arm 1 , and the lead screw nut 8 is driven by the lead screw 4 to cause the wedge block 9 to be subjected to force to drive the follower arm 1 to rise and fall.

[0039] like Figure 2 and Figure 3As shown, in this embodiment, the linear telescopic mechanism 2 is a cylinder, which includes a cylinder barrel and a piston rod. A cylinder barrel support is provided at the bottom of the cylinder barrel, and the cylinder barrel is hinged to the cylinder barrel support, and the cylinder barrel support is fixed on the frame. There is a displacement sensor on the cylinder, which adopts a linear Hall sensor and is connected to the controller, wherein the output analog signal of the displacement sensor is output to the analog input port of the controller through a shielded cable. The clamping mechanism 6 adopts an adjustable clamping claw structure, which is used to adapt to pipe fittings 5 ​​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 fitting 5 during the clamping process.

[0040] Specifically,

[0041] The follower mechanism of this embodiment is made of high-strength alloy steel to ensure that it has sufficient bearing capacity and stability to support pipes 5 of various specifications. The follower arm 1 is designed as a box-type structure with reinforcing ribs inside to reduce its own weight while enhancing its bending and torsion resistance. Its bottom end is connected to the base through a processed hinge seat, and the base is bolted to the thickened mounting plate at the bottom of the pipe cutting machine frame to ensure the firmness and reliability of the connection. The clamping mechanism 6 is installed at the top of the follower arm 1, and adopts an adjustable clamping claw design, which can adapt to pipes 5 of different diameters, and 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, and the friction resistance is reduced by a self-lubricating joint bearing to ensure the smoothness and stability of the lifting and lowering movement of the follower arm 1. The cylinder uses a high-precision, high-sealing cylinder drive, which has good linear telescopic performance and rapid response capability, and its working 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 position of the follower arm 1. The roller 16 at the lower part of the follower frame 7 forms rolling contact with the wedge block 9. The surface of the wedge block 9 is quenched to improve its wear resistance and hardness. Its shape and angle are optimized. During the lifting process of the follower arm 1, the follower arm 1 can be accurately limited to prevent it from excessive swinging or deviation, ensuring the accuracy and stability of the support, while reducing the vibration and noise of the follower arm 1 during the movement.

[0043] like Figure 6As shown, the lead screw 4 of this embodiment adopts a trapezoidal lead screw, which has high transmission efficiency and positioning accuracy, and its lead is selected according to the lifting stroke and speed requirements of the follower arm 1. Both ends of the lead screw 4 are installed on the bearing seat of the bottom frame of the pipe cutting machine through angular contact ball bearings to ensure the stability and rigidity of the lead screw 4 when rotating at high speed. The servo motor uses an AC servo motor with precise speed control and position control capabilities. It is directly connected to the lead screw 4 through an elastic coupling to reduce transmission errors and vibrations. The lead screw nut 8 adopts a double nut pre-tightening structure to effectively eliminate reverse clearance and ensure the linear motion accuracy of the lead screw nut 8 on the lead screw 4.

[0044] The cylinder of this embodiment adopts a rear-mounted earring installation method. The cylinder support is welded to the frame and is subjected to aging treatment to eliminate welding stress to ensure the structural strength and stability of the cylinder support. A seal is used between the cylinder and the cylinder piston rod to prevent gas leakage and ensure the working performance and service life of the cylinder. A throttle valve and a one-way valve are installed at the inlet and outlet of the cylinder to adjust the flow and pressure of the air pressure, realize the precise control of the cylinder extension speed and the pressure-maintaining function, so as to meet the requirements of the follower arm 1 for support force and movement speed under different working conditions.

[0045] The displacement sensors on the cylinder of this embodiment all adopt 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 feedback from 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 4The clamping mechanism shown, the clamping seat 10 and the clamping seat 2 11 are key components in the clamping mechanism, which are used to directly clamp the workpiece. They are arranged relative to each other so that the workpiece can be clamped from both sides. The clamping seat 10 and the clamping seat 2 11 are connected. The clamping seat 10 and the clamping seat 2 11 are installed on the slide rail 12 so that they can move linearly along the slide rail 12. The slide rail 12 plays a guiding role to ensure the accuracy and stability of the clamping seat during movement. The support roller 13 is used to reduce the friction of the clamping seat during movement, so that it moves more smoothly. The support roller 13 is installed at the bottom of the clamping seat to support and assist the movement of the clamping seat through rolling contact. The support 14 plays the role of supporting the entire clamping mechanism. It is connected to the support frame 15 to provide a stable foundation for the entire mechanism. When the workpiece needs to be clamped, the clamping seat 10 and the clamping seat 2 11 move toward each other along the slide rail 12 under the action of the driving force. Due to the guiding effect of the slide rail 12, the clamping seat can accurately clamp the workpiece. The support roller 13 can reduce the resistance of the clamping seat movement in this process, making the clamping action faster and smoother. When the workpiece needs to be released, the external driving force acts in the reverse direction, causing the clamping seat 10 and the clamping seat 2 11 to move in the reverse direction 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 multiple follower arms 1 to rise and fall synchronously, the controller controls the speed and direction of the servo motor to rotate the lead screw 4 and drive the lead screw nut 8 to move, and the lead screw nut 8 drives the follower frame 7 above the wedge block 9 to make the follower arms 1 rise and fall synchronously; 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 individually, 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 movement; the controller coordinately controls the speed of the lead screw 4 and the cylinder air pressure to control some follower arms 1 to perform lifting movement. The controller coordinates the rotation speed of the lead screw 4 and the cylinder air pressure to control the lifting and lowering movement of part of the follower arm 1, including calculating the PID control parameters according to 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 term, differential term and proportional term 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 part of the follower arm 1, including calculating the PID control parameters according to 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, 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, adjusting the opening degree of the electromagnetic proportional valve through the command value, and controlling the cylinder air pressure.

[0049] Specifically,

[0050] When the pipe cutting machine starts working or the specifications of the pipe fitting 5 change, the controller first calculates the initial synchronous lifting position required by the follower arm 1 according to the preset program and the parameter information of the pipe fitting 5. Then, the corresponding control command is sent to the servo motor to drive the screw 4 to rotate. The servo motor adopts a closed-loop control method. The encoder installed on the motor shaft feeds back the motor's speed and position information in real time. The controller controls the motor's speed and position accurately based on this feedback information to ensure 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 direction of the screw. Under the coordinated action of the screw 4, multiple screw nuts 8 simultaneously push the corresponding wedge blocks 9 to move. Due to the limiting relationship between the wedge block 9 and the follower arm 1, the follower arm 1 achieves synchronous lifting and lowering motion under the action of the wedge block 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 supporting state during the processing process, and adapt 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 barrel to adjust the air intake and return air flow of the cylinder barrel, 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. 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 the influence of the adjustment of a single follower arm 1 on other parts. 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, which can predict the movement trend and force requirements of the follower arm 1 in advance according to the real-time changes in the processing of the pipe 5, 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] Among them, the analog signal voltage value of the current position of the follower arm is obtained by the displacement sensor installed on the cylinder, and the voltage signal output by the displacement sensor on the cylinder is V1. The analog signal is converted into the actual displacement value using the calibration coefficient of the sensor. Assuming that the calibration coefficient of the displacement sensor on the cylinder is K1 (unit: meter / volt), the current position X1 (unit: meter) corresponding to the cylinder and the current position X2 (unit: meter) corresponding to the wedge block are calculated by 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 processing technology of the pipe 5 from the pipe cutting machine control system, such as the current cutting position coordinates (xc, yc) (unit: meter), cutting speed vc (unit: meter / second), and target size of the pipe 5 including 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. According to the process parameters such as the current cutting position, cutting speed and target size of the pipe 5, combined with the geometric relationship between the follower arm 1 and the pipe 5, the target position that the follower arm 1 should reach in the current processing stage is determined through the geometric calculation model. Based on the assumption of the linear cutting path of the pipe 5, the target horizontal position Xt (unit: meter) and vertical position Yt (unit: meter) of the follower arm 1 are calculated according to the distance relationship between the cutting position and the follower arm 1 and the preset support spacing requirements. For synchronous lifting and lowering movements, the target vertical position Yt of all follower arms 1 is the same, and the target horizontal position Xt is determined according to the overall horizontal movement of the pipe 5. For independent lifting and lowering movements, when the local shape change of the pipe 5 is detected, the specific target vertical position Yt of the affected follower arm 1 is calculated through more sophisticated local geometric analysis and mechanical models (considering factors such as the local curvature and wall thickness change of the pipe 5), while the horizontal position Xt remains unchanged or is adjusted accordingly according to the overall processing situation.

[0058] Then, according to the material, size and cutting process requirements of the pipe 5, the target support force Ft (unit: Newton) that the follower arm needs to provide is calculated through the mechanical analysis model. Considering the weight of the pipe 5 during the cutting process, the bending moment caused by the cutting force and other factors, based on the beam theory of material mechanics (if the pipe 5 is approximately regarded as a beam structure) or the simplified finite element analysis model (for more complex pipe 5 shapes and stress conditions), the support force that each support point (i.e., the follower arm position) should bear is calculated as the target support force Ft.

[0059] Among them, the PID control algorithm is used to control the speed of the servo motor. First, the deviation between the current position of the follower arm 1 and the target position in the horizontal and vertical directions is calculated. Assume that 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, an integral calculation is performed every fixed time interval, which can be expressed as: (For horizontal 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 the discretization method is used 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 term, integral term and differential term of PID control to get the speed control command value of the servo motor in the horizontal and vertical directions (unit: revolutions per minute, rpm). 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 command, among which 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 needs 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 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 degree 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 the pipe 5, when the pipe 5 has an irregular shape or the cutting position changes, some follower arms 1 need to be controlled separately to ensure that the pipe 5 is always stably supported. For example, when processing a pipe with a special shape, a certain section of the pipe 5 is partially bent, which requires independent lifting and lowering adjustments of some follower arms 1. First, the displacement sensor installed on the cylinder obtains the current position information of the follower arm 1 in real time and feeds the signal back to the controller.

[0076] Assume that a follower arm 1 is A. When the 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 calibration coefficient of the sensor is used to convert the analog signal into the actual displacement value. Assume that the calibration coefficient of the displacement sensor on the cylinder is K1 (unit: meter / volt), then the current position X1A (unit: meter) on the cylinder and the current position X2A (unit: meter) corresponding to 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 technology from the pipe cutting machine control system, such as the current cutting position coordinates (Xc, Yc) (unit: meter), cutting speed Vc (unit: meter / second), and target dimensions of pipe 5, including pipe diameter and wall thickness information. Based on these parameters and the preset control algorithm and process requirements, combined with the geometric shape of the local bend of pipe 5, the target position that the follower arm A should reach in the current processing stage is determined through the geometric calculation model, including the target horizontal position XtA (unit: meter) and the target vertical position YtA (unit: meter). At the same time, according to the material, size and cutting process requirements of the pipe, the target support force FtA (unit: Newton) required to be provided by the follower arm A is calculated through the mechanical analysis model.

[0079] Assume that follower arm 1 is A, and calculate the deviation between the current position of follower arm A and the target position in the horizontal and vertical directions. Assume that the horizontal position deviation is exA (unit: meter), and the vertical position deviation is eyA (unit: meter), and the calculation formula is 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, 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:

[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 degree 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 perform independent lifting and lowering movements to adapt to the special local conditions of the pipe fitting 5, ensuring that the pipe fitting 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 installed at the bottom of the cylinder barrel, the cylinder barrel is hinged to the support, and the support is fixed on 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 with its bottom end and the frame hinge point as the axis. 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 bottom end of the follower arm 1 and the top hinge point of the linear telescopic mechanism 2 to the bottom end of the follower arm and the frame hinge point 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 is lifted, h1 will increase, and L1 will also increase, but the change in h1 is not linearly related to the change in L1, so the angle will change accordingly according to the extended length of the piston rod. In actual work, the displacement sensor monitors the telescopic length of the piston rod in real time. Combined with the geometric parameters of the follower arm A and the installation position relationship, the controller can accurately calculate the change in the angle of the linear telescopic mechanism 2, thereby controlling the lifting and lowering movement of the follower arm A more accurately.

[0086] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope 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 protection scope 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 frame of the pipe cutting machine, 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 frame of the pipe cutting machine, and the linear telescopic mechanism and the servo motor are respectively communicated with the controller to cooperate with each other to jointly control the lifting and lowering of the follower mechanism.

2. A follow-up support mechanism for a pipe cutting machine according to claim 1, characterized in that: 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. A clamping mechanism is installed on the top of the follower arm. The upper end of the follower frame is fixedly connected to the middle position of the follower arm, and a roller is installed at the lower end of the follower frame.

3. A follow-up support mechanism for a pipe cutting machine according to claim 2, characterized in that: The lead screw is installed 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 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 through the rotation of 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 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 slidably connected to the guide rail.

4. A follow-up support mechanism for a pipe cutting machine according to claim 3, characterized in that: The side surface of the wedge block is connected to the lead screw nut and driven by the lead screw nut to slide on the guide rail. 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.

5. A follow-up support mechanism for a pipe cutting machine according to claim 4, characterized in that: The linear telescopic mechanism is a pneumatic cylinder or a hydraulic cylinder, wherein the linear telescopic mechanism comprises 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.

6. A follow-up support mechanism for a pipe cutting machine according to claim 5, characterized in that: 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.

7. A follow-up support mechanism for a pipe cutting machine according to claim 6, 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.

8. A control method for a follow-up support mechanism of a pipe cutting machine, characterized in that: The pipe cutting machine follow-up support mechanism according to claim 6 comprises: When controlling multiple follower arms to rise and fall synchronously, the controller controls the speed and direction of the servo motor to rotate the lead screw and drive the lead screw nut to move, and the lead screw nut drives the follower frame above the wedge block to make the follower arms rise and fall 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 some follower arms are controlled individually, the pressure in the cylinder is controlled by the controller to extend and retract the piston rod, and the piston rod is used to support each follower arm to perform independent lifting and lowering movements; The controller coordinately controls the screw speed and the pressure in the cylinder to control the lifting and lowering movement of part of the follower arm.

9. A control method for a follow-up support mechanism of a pipe cutting machine according to claim 8, characterized in that: The controller collaboratively controls the screw speed and the pressure in the cylinder to control the lifting movement of part of the follower arm, including signal parameters obtained by the displacement sensor of the linear telescopic mechanism, calculating the PID control parameters 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.

10. A control method for a follow-up support mechanism of a pipe cutting machine according to claim 9, characterized in that: The controller is used to coordinately control the screw speed and the pressure in the cylinder to control part of the follower arm to perform lifting and lowering movements. It also includes calculating PID control parameters based on signal parameters obtained by a displacement sensor on the linear telescopic mechanism according to the deviation between the current supporting force of the linear telescopic mechanism and the target supporting 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 pressure in the cylinder.

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