Follow-up adjusting device and method for tube bundle laser cladding head

Abstract

The invention relates to the technical field of laser cladding, and particularly discloses a follow-up adjusting device and method for a tube bundle laser cladding head, the follow-up adjusting device comprises a vertical driving mechanism, a swing mechanism, the laser cladding head, a distance sensor and a control unit, the swing mechanism comprises a lifting seat connected with the vertical driving mechanism, and the lifting seat is connected with the laser cladding head. A rotating motor for driving the laser cladding head to swing is arranged in the lifting seat; the distance sensor is positioned on one side of the laser cladding head through a connecting frame; the height of the laser cladding head is adjusted in real time according to the deformation of the pipe by adopting a real-time compensation mode when the pipe row is radially machined, and the height of the laser cladding head can be adjusted based on the real data of the machining point of the pipe by adopting a position compensation mode when the pipe row is transversely machined, so that the machining precision is effectively ensured; radial and axial machining is achieved, modeling is not needed in the two compensation modes, the calculated amount is greatly reduced, and cost and time are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of laser cladding, and in particular to a follow-up adjustment device and method for a tube row laser cladding head. Background Art

[0002] Laser cladding technology has been used for a short time in tube banks, and the main pain points are: 1) The previous process is welding, and there are certain differences between the actual object and the model, so direct programming is inaccurate; 2) During the cladding process, the tube banks are greatly deformed by heat, and the change in working distance (the distance from the powder nozzle to the workpiece surface) leads to a decline in cladding quality or even failure to form.

[0003] To this end, patent CN113977075A discloses a method for automatic trajectory guidance of water-cooled wall tube row cladding. A method for automatic trajectory guidance of water-cooled wall tube row cladding is roughly described as adopting a method of vision → reverse modeling → path planning, but it has the following disadvantages: 1) Warping may also occur in the scanning area during cladding. When this happens, manual secondary scanning, secondary modeling and secondary path planning are required, which is quite cumbersome. It requires a large amount of data calculation for the CPU, a slow calculation processing speed, and high requirements for computer configuration, resulting in high processing costs; 2) There are requirements for the forward direction of laser cladding, and it can only move forward along the axial direction (length direction). Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a follow-up adjustment device and method for a tube row laser cladding head, which effectively ensures processing accuracy and realizes radial and axial processing. Both compensation methods do not require modeling, greatly reducing the amount of calculation, cost and time.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A follow-up adjustment device for a tube row laser cladding head comprises a vertical drive mechanism, a swing mechanism, a laser cladding head, a distance sensor and a control unit. The swing mechanism comprises a lifting seat connected to the vertical drive mechanism, and a rotating motor for driving the laser cladding head to swing is arranged in the lifting seat. The distance sensor is located on one side of the laser cladding head through a connecting frame.

[0007] Preferably, the vertical drive mechanism includes a fixed seat, a sliding seat and a drive motor, the fixed seat is provided with a parallel lead screw and a guide rail, one end of the lead screw is connected to the drive motor, one side of the sliding seat is provided with a sliding block cooperating with the guide rail and a nut sleeve cooperating with the lead screw, and the sliding seat is connected to the lifting seat.

[0008] Preferably, the horizontal distance between the distance sensor and the laser cladding head is less than 250 mm.

[0009] A follow-up adjustment method for a tube row laser cladding head is implemented based on a vertical drive mechanism, a swing mechanism, a distance sensor and a control unit matched with the laser cladding head. The distance sensor is located at the front end of the laser cladding head, and the horizontal distance between the distance sensor and the laser cladding head is less than 250 mm. The follow-up adjustment method is:

[0010] (1) According to the cladding direction, the tracking mode is selected. The tracking mode includes real-time compensation mode and position compensation mode. When the tube row is processed radially, the real-time compensation mode is used, and when the tube row is processed transversely, the position compensation mode is used;

[0011] (2) After the data processing sub-thread filters the height data, it is passed to the PID algorithm sub-thread to calculate the current height position of the laser cladding head. The height of the laser cladding head is adjusted by the vertical drive mechanism to achieve a constant cladding height.

[0012] Preferably, the real-time compensation mode collects height data fed back by a distance sensor, performs real-time processing, and adjusts the height of the laser cladding head.

[0013] Preferably, the position compensation mode collects height data fed back by the distance sensor for processing, stores the processed height deviation data in a register of the control unit, and adjusts the height of the laser cladding head when the laser cladding head moves to the position.

[0014] Preferably, the data filtering processing method includes mean filtering, median filtering, first-order (αβ) filtering, and limiting filtering.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. When the present invention performs radial processing on the tube row, a real-time compensation mode is adopted to adjust the height of the laser cladding head in real time according to the deformation of the tube. When the tube row is processed transversely, a position compensation mode is adopted to adjust the height of the laser head based on the real data of the tube processing point, thereby effectively ensuring the processing accuracy and realizing radial and axial processing. Both compensation methods do not require modeling, which greatly reduces the amount of calculation, cost and time.

[0017] 2. Both compensation modes of the present invention are based on real-time detection of the tube surface to adjust the height of the laser head, which has higher processing accuracy and improves the overall cladding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the follow-up adjustment device;

[0019] Figure 2 It is a structural schematic diagram of the adjustment seat;

[0020] Figure 3 It is a schematic diagram of the structure during laser cladding;

[0021] In the figure: 1-vertical drive mechanism; 101-fixed seat; 102-screw; 103-guide rail; 104-slide seat; 2-lifting seat; 3-rotating motor; 4-laser cladding head; 5-connecting frame; 6-distance sensor; 7-control unit. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, a follow-up adjustment device of a laser cladding head 4 for a pipe row includes a vertical driving mechanism 1, a swinging mechanism, a laser cladding head 4, a distance sensor 6 and a control unit 7. The vertical driving mechanism 1 is used to adjust the height of the laser cladding head 4, the swinging mechanism is used to adjust the angle of the laser cladding head 4, the swinging mechanism includes a lifting seat 2 connected to the vertical driving mechanism 1, and a rotating motor 3 for driving the laser cladding head 4 to swing is arranged in the lifting seat 2. The distance sensor 6 is located on one side of the laser cladding head 4 through a connecting frame 5. The basic principle is that the distance sensor 6 transmits the distance information to the control unit 7, and the control unit 7 adjusts the distance through the vertical driving mechanism 1 according to different working modes through a set PID operation method, so as to achieve a constant working distance of the laser cladding head 4.

[0024] like Figure 2 As shown, the vertical drive mechanism 1 includes a fixed seat 101, a slide seat 104 and a drive motor. A parallel lead screw 102 and a guide rail 103 are provided in the fixed seat 101. One end of the lead screw 102 is connected to the drive motor. One side of the slide seat 104 is provided with a slider that cooperates with the guide rail 103 and a nut sleeve that cooperates with the lead screw 102. The slide seat 104 is connected to the lifting seat 2.

[0025] The horizontal distance between the distance sensor 6 and the laser cladding head 4 is less than 250 mm.

[0026] A follow-up adjustment method for a tube row laser cladding head 4 is implemented based on a vertical drive mechanism 1, a swing mechanism, a distance sensor 6 and a control unit 7 matched with the laser cladding head 4. The vertical drive mechanism 1 is used to adjust the height of the laser cladding head 4, and the swing mechanism is used to adjust the angle of the laser cladding head 4. During operation, the head 4 is swung first and then the height is adjusted. The distance sensor 6 is located at the front end of the laser cladding head 4.

[0027] like Figure 3 As shown, the follow-up adjustment method is:

[0028] 1. According to the cladding direction, select the tracking mode, which includes real-time compensation mode and position compensation mode. When the tube row is processed radially, the real-time compensation mode is used, and when the tube row is processed horizontally, the position compensation mode is used;

[0029] The real-time compensation mode collects the height data fed back by the distance sensor 6, processes it in real time and adjusts the height of the laser cladding head 4. The distance sensor 6 is located at the front end of the laser cladding head 4, and the horizontal distance between the distance sensor 6 and the laser cladding head 4 is less than 250mm. The maximum deformation in this area is ≤250×0.5%=1.25mm, and the allowable error of the laser cladding working distance is about ±2mm. Therefore, we believe that the detection point is highly consistent with the laser cladding operation point. The working principle at this time is real-time compensation, that is, real-time calculation of the compensation difference, real-time adjustment of the height of the laser cladding head 4, so as to achieve a constant working distance of the laser cladding head 4.

[0030] The position compensation mode collects the height data fed back by the distance sensor 6 for processing, and stores the processed height deviation data in the register of the control unit 7. When the laser cladding head 4 moves to this position, the height of the laser cladding head 4 is adjusted, that is, the compensation data is given with a delay and then the height of the laser head is adjusted. Therefore, this mode is more accurate than the real-time compensation mode.

[0031] 2. The data processing subthread filters the height data. The processing directions include:

[0032] 2.1 Mean filtering: The value of a point in the data sequence is replaced by the average value of multiple data around the point. This method is simple and often used to eliminate random noise and reduce the impact of interference in the height detection process on the final tracking data.

[0033] 2.2 Median filtering: The median value of a fixed-size window in the data sequence is used to replace the value of the window center point. It is particularly suitable for eliminating impulse noise or outliers. This algorithm performs well in preserving signal edges and is used to reduce outliers caused by the laser reflection angle of the distance sensor 6.

[0034] 2.3 First-order (αβ) filtering: An exponential-based filtering method suitable for online data processing. It can respond quickly to data changes and is particularly suitable for real-time systems.

[0035] 2.4 Limiting filter: By setting the maximum allowable deviation to limit the fluctuation of data, it has a good inhibitory effect on occasional pulse interference and prevents excessive data from causing damage to the equipment.

[0036] 2.5 Weighted average filtering: Each sample value is multiplied by a weight and then summed. The weight is usually assigned according to the importance of the sample value. This method can pay attention to the new height deviation data while still considering the impact of the old height deviation data.

[0037] 2.6 Arithmetic average filtering: Continuously sample N data and perform arithmetic averaging, which is used for signal processing of general random interference.

[0038] After the filtering process is completed, it is passed to the PID algorithm sub-thread to calculate the height position of the current laser cladding head 4. The PID algorithm data processing flow is divided into the following steps:

[0039] First, in the PID algorithm, the role of the proportional link (P) is to adjust the control amount in proportion to the current error. When the deviation between the system output and the height data increases, the proportional link will immediately produce a larger control effect, thereby speeding up the system response. However, simple proportional control cannot eliminate steady-state errors, and excessive proportional gain may cause system instability.

[0040] Secondly, the integral link (I) compensates for the shortcomings of the proportional link by accumulating historical errors, with the goal of reducing the long-term accumulated errors to zero. The integral term can effectively eliminate the error after the system reaches a steady state and improve the control accuracy. However, too strong an integral effect will cause the system to react slowly and may cause overshoot.

[0041] Furthermore, the differential link (D) makes adjustments in advance by predicting the changing trend of the future error. It reacts according to the speed of error change and can make adjustments before the error becomes larger, thereby increasing the damping of the system, reducing oscillation and overshoot, and improving the stability and dynamic performance of the system.

[0042] The Z′ axis position is finally calculated through the PID algorithm subthread, and the height of the laser cladding head 4 is adjusted by the vertical drive mechanism 1 to achieve a constant cladding height.

[0043] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A follow-up adjustment device for a tube row laser cladding head, characterized in that: It includes a vertical driving mechanism, a swinging mechanism, a laser cladding head, a distance sensor and a control unit. The swinging mechanism includes a lifting seat connected to the vertical driving mechanism. The lifting seat is provided with a rotating motor for driving the laser cladding head to swing. The distance sensor is located on one side of the laser cladding head through a connecting frame.

2. The follow-up adjustment device of the tube row laser cladding head according to claim 1, characterized in that: The vertical drive mechanism includes a fixed seat, a slide seat and a drive motor. A parallel lead screw and a guide rail are arranged in the fixed seat. One end of the lead screw is connected to the drive motor. A slider that cooperates with the guide rail and a nut sleeve that cooperates with the lead screw are arranged on one side of the slide seat. The slide seat is connected to the lifting seat.

3. The follow-up adjustment device of the tube row laser cladding head according to claim 1, characterized in that: The horizontal distance between the distance sensor and the laser cladding head is less than 250 mm.

4. A follow-up adjustment method for a tube row laser cladding head, based on a vertical drive mechanism, a swing mechanism, a distance sensor and a control unit matched with the laser cladding head, characterized in that: The distance sensor is located at the front end of the laser cladding head, and the horizontal distance between the distance sensor and the laser cladding head is less than 250 mm. The follow-up adjustment method is: (1) According to the cladding direction, the tracking mode is selected. The tracking mode includes real-time compensation mode and position compensation mode. When the tube row is processed radially, the real-time compensation mode is used, and when the tube row is processed transversely, the position compensation mode is used; (2) After the data processing sub-thread filters the height data, it is passed to the PID algorithm sub-thread to calculate the current height position of the laser cladding head. The height of the laser cladding head is adjusted by the vertical drive mechanism to achieve a constant cladding height.

5. The follow-up adjustment method of a tube row laser cladding head according to claim 4, characterized in that: The real-time compensation mode collects height data fed back by the distance sensor, performs real-time processing and adjusts the height of the laser cladding head.

6. The follow-up adjustment device and method of a tube row laser cladding head according to claim 4, characterized in that: The position compensation mode collects height data fed back by the distance sensor for processing, stores the processed height deviation data in a register of the control unit, and adjusts the height of the laser cladding head when the laser cladding head moves to the position.

7. The follow-up adjustment method of a tube row laser cladding head according to claim 4, characterized in that: The data filtering processing method includes mean filtering, median filtering, first-order (αβ) filtering and limiting filtering.

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