A kind of servo adjusting device and method of tube row laser cladding head

Abstract

The present application relates to the technical field of laser cladding, and particularly discloses a follow-up adjusting device and method of a tube row laser cladding head, which comprises a vertical driving mechanism, a swing mechanism, a laser cladding head, a distance sensor and a control unit, the swing mechanism comprises a lifting seat connected with the vertical driving mechanism, a rotating motor for driving the laser cladding head to swing is arranged in the lifting seat, and the distance sensor is located on one side of the laser cladding head through a connecting frame; when the tube row is processed in the radial direction, a real-time compensation mode is adopted, the height of the laser cladding head is adjusted in real time according to the deformation of the tube, when the tube row is processed in the transverse direction, a position compensation mode is adopted, the height of the laser head can be adjusted based on the real data of the tube processing point, the processing precision is effectively ensured, radial and axial processing is realized, and both the two compensation modes do not need to be modeled, so that the calculation amount is greatly reduced, and the cost and time are reduced.

Description

Technical Field

[0001] This invention relates to the field of laser cladding technology, specifically to a follow-up adjustment device and method for a tube array laser cladding head. Background Technology

[0002] The use of laser cladding technology for tube arrays is relatively recent, and the main challenges are: 1) The preceding process is welding, and there are certain differences between the actual product and the model, making direct programming inaccurate; 2) The tube array is subject to significant heat deformation during the cladding process, and changes in the working distance (distance from the powder feeding nozzle to the workpiece surface) lead to a decline in cladding quality or even failure to form.

[0003] To address this, patent CN113977075A discloses an automatic trajectory guidance method for cladding water-cooled wall tubes. This method is roughly described as using a vision → reverse modeling → path planning approach, but it has the following drawbacks: 1) Warping may occur in the scanned area during cladding. When this happens, manual secondary scanning, secondary modeling, and secondary path planning are required, which is quite cumbersome. It places a large amount of data calculation on the CPU, has a slow processing speed, and requires high computer configuration, resulting in high processing costs; 2) There are requirements for the direction of laser cladding, which can only proceed along the axial direction (length direction). Summary of the Invention

[0004] This invention addresses the aforementioned shortcomings of existing technologies by providing a follow-up adjustment device and method for a tube array laser cladding head. This effectively ensures processing accuracy, enables radial and axial processing, and eliminates the need for modeling for both compensation methods, significantly reducing computational load and lowering costs and time.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A follow-up adjustment device for a tube-type laser cladding head includes a vertical drive mechanism, a swing mechanism, a laser cladding head, a distance sensor, and a control unit. The swing mechanism includes a lifting base connected to the vertical drive mechanism. The lifting base is equipped with a rotary motor that drives the laser cladding head to swing. The distance sensor is located on one side of the laser cladding head via a connecting frame.

[0007] Preferably, the vertical drive mechanism includes a fixed base, a slide, and a drive motor. The fixed base 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 slide is provided with a slider that cooperates with the guide rail and a nut sleeve that cooperates with the lead screw. The slide is connected to the lifting base.

[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 realized based on a vertical drive mechanism, a swing mechanism, a distance sensor and a control unit that are 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 as follows:

[0010] (1) According to the cladding direction, select the tracking mode. The tracking mode includes a real-time compensation mode and a position compensation mode. When performing radial processing on the tube row, the real-time compensation mode is adopted. When performing transverse processing on the tube row, the position compensation mode is adopted;

[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 in a follow-up manner through the vertical drive mechanism to achieve a constant cladding height.

[0012] Preferably, the real-time compensation mode is to collect the height data fed back by the distance sensor, perform real-time processing and adjust the height of the laser cladding head.

[0013] Preferably, the position compensation mode is to collect the height data fed back by the distance sensor for processing, store the processed height deviation data in the register of the control unit, and adjust the height of the laser cladding head when the laser cladding head moves to this position.

[0014] Preferably, the data filtering processing methods include mean filtering, median filtering, first-order (αβ) filtering, and limit filtering.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. When the present invention performs radial processing on the tube row, the real-time compensation mode is adopted, and the height of the laser cladding head is adjusted in real time according to the deformation of the pipe material. When performing transverse processing on the tube row, the position compensation mode is adopted, and the height of the laser head can be adjusted based on the real data of the pipe material processing point positions, effectively ensuring the processing accuracy, realizing radial and axial processing, and neither of the two compensation methods requires modeling, greatly reducing the calculation amount, cost and time.

[0017] 2. The two compensation modes of the present invention are both height adjustments of the laser head based on the real-time detection of the pipe material surface, with higher processing accuracy and improved overall cladding effect. 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 This is a schematic diagram of the structure during laser cladding;

[0021] In the diagram: 1-Vertical drive mechanism; 101-Fixed seat; 102-Screw; 103-Guide rail; 104-Slide seat; 2-Lifting seat; 3-Rotary motor; 4-Laser cladding head; 5-Connecting frame; 6-Distance sensor; 7-Control unit. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, a follow-up adjustment device for a tube-type laser cladding head 4 includes a vertical drive mechanism 1, a swing mechanism, a laser cladding head 4, a distance sensor 6, and a control unit 7. 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. The swing mechanism includes a lifting base 2 connected to the vertical drive mechanism 1, and a rotary motor 3 that drives the laser cladding head 4 to swing is installed inside the lifting base 2. The distance sensor 6 is located on one side of the laser cladding head 4 via a connecting frame 5. The basic principle is as follows: the distance sensor 6 transmits distance information to the control unit 7. The control unit 7 adjusts the distance through the vertical drive mechanism 1 according to different working modes using a pre-set PID calculation method, thereby achieving a constant working distance of the laser cladding head 4.

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

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

[0026] A follow-up adjustment method for a tube-type 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 that are 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 swing mechanism first adjusts the height and then the height. 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 as follows:

[0028] 1. Select the tracking mode according to the cladding direction. The tracking mode includes real-time compensation mode and position compensation mode. When the pipe bank is radially processed, the real-time compensation mode is used, and when the pipe bank is transversely processed, the position compensation mode is used.

[0029] The real-time compensation mode involves collecting height data from the distance sensor 6, processing it in real time, and adjusting 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, while the allowable error of the laser cladding working distance is about ±2mm. Therefore, we assume that the detection point and the laser cladding operation point are at the same height. The working principle at this time is real-time compensation, that is, calculating the compensation difference in real time and adjusting the height of the laser cladding head 4 in real time, thereby achieving a constant working distance of the laser cladding head 4.

[0030] The position compensation mode collects and processes the height data fed back by the distance sensor 6, 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 after 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 sub-thread filters the altitude data, including the following aspects:

[0032] 2.1 Mean Filtering: This method replaces the value of a point in a data sequence with the average of multiple data points surrounding that point. It is simple and commonly used to eliminate random noise and reduce the impact of interference during height detection on the final tracking data.

[0033] 2.2 Median Filtering: This method replaces the value at the center point of a fixed-size window within a data sequence with the median value. 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 laser reflection angles in the distance sensor 6.

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

[0035] 2.4 Amplitude Limiting Filter: By setting the maximum allowable deviation, it limits data fluctuations and effectively suppresses occasional pulse interference, preventing excessive data from damaging the equipment.

[0036] 2.5 Weighted Average Filtering: Each sampled value is multiplied by a weight and then summed. The weights are usually assigned according to the importance of the sampled values. This method can give importance to new height deviation data while still considering the influence of old height deviation data.

[0037] 2.6 Arithmetic Mean Filtering: The arithmetic mean of N consecutively sampled data is used for signal processing with general random interference.

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

[0039] First, in the PID algorithm, the proportional element (P) adjusts the control input proportionally to the magnitude of the current error. When the deviation between the system output and the altitude data increases, the proportional element immediately generates a larger control action, thereby accelerating the system's response speed. However, simple proportional control cannot eliminate steady-state error, and excessively large proportional gain may lead to system instability.

[0040] Secondly, the integral term (I) compensates for the shortcomings of the proportional term by accumulating historical errors, aiming to reduce the long-term accumulated error to zero. The integral term can effectively eliminate the error after the system reaches steady state, improving control accuracy. However, excessive integral action can lead to sluggish system response and may cause overshoot.

[0041] Furthermore, the differential element (D) adjusts in advance by predicting the future trend of error changes. It reacts according to the rate of error change and can adjust before the error becomes large, thereby increasing the damping of the system, reducing oscillations and overshoot, and improving the stability and dynamic performance of the system.

[0042] The Z′ axis position is finally calculated by the PID algorithm sub-thread, 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 modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A follow-up adjustment device for a tube-type laser cladding head, characterized in that: It includes a vertical drive mechanism, a swing mechanism, a laser cladding head, a distance sensor, and a control unit. The swing mechanism includes a lifting base connected to the vertical drive mechanism. The lifting base is equipped with a rotary motor that drives the laser cladding head to swing. The distance sensor is located at the front end of the laser cladding head through a connecting frame. The horizontal distance between the distance sensor and the laser cladding head is less than 250mm. The follow-up adjustment method includes the following steps: (1) Select the tracking mode according to the cladding direction. The tracking mode includes real-time compensation mode and position compensation mode. When the pipe bank is radially processed, the real-time compensation mode is used. The real-time compensation mode is to collect the height data fed back by the distance sensor, process it in real time and adjust the height of the laser cladding head. When the pipe bank is transversely processed, the position compensation mode is used. The position compensation mode is to collect the height data fed back by the distance sensor, process it, and store the processed height deviation data in the register of the control unit. When the laser cladding head moves to this position, the height of the laser cladding head is adjusted. (2) After the data processing sub-thread performs filtering on 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. The data filtering methods include mean filtering, median filtering, first-order αβ filtering and amplitude limiting filtering.

2. The follow-up adjustment device for a tube-type laser cladding head as described in claim 1, characterized in that: The vertical drive mechanism includes a fixed base, a slide block, and a drive motor. The fixed base is equipped 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 slide block is equipped with a slider that cooperates with the guide rail and a nut sleeve that cooperates with the lead screw. The slide block is connected to the lifting base.

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