Self-adaptive coupling system for water-jet guided laser nozzle

Abstract

The utility model belongs to the technical field of water guide processing, and relates to a self-adaptive coupling system for a water guide laser nozzle, which comprises a laser beam expanding-focusing unit, a coupling unit, an observation system, a water supply system and a three-dimensional workbench, the observation system is used for monitoring the position and state of laser in a nozzle small hole in real time, the laser beam expanding-focusing unit is optically connected to the coupling unit, the observation system is photoelectrically connected to the coupling unit and the three-dimensional workbench, and the water supply system is connected to the coupling unit through a water path; whether laser and the nozzle deviate from the center or not can be monitored in real time in the machining process, machining is prevented from being affected, and therefore the service life of the nozzle can be effectively prolonged, cost can be saved, machining stability can be guaranteed, time cost is saved, and meanwhile machining efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of water guide processing and relates to a system for adaptive coupling of a water guide laser nozzle. Background Art

[0002] The water guide laser processing technology is a new processing technology. Its principle is to couple the laser into a water beam of dozens of micrometers, and utilize the total reflection phenomenon of the laser in water to form a stable laser water jet processing interval of dozens of millimeters. Compared with traditional laser processing, it has a longer working distance. At the same time, a very high power density is maintained inside the water jet, which can achieve ablation residues on the surface of the workpiece, and also greatly reduces the heat affected zone on the processing surface. However, for a long time, the stability of processing has become a problem that everyone is concerned about and urgently needs to solve. The alignment of the laser and the nozzle center in the prior art mainly locates by using a CCD camera to photograph the laser spot and the nozzle, then adjusts the X and Y axes of the coupling device to move the nozzle center to the center of the spot, and finally fine-tunes by combining CCD imaging and the coupled power. During the alignment process, marking the center of the laser spot, and the movement of the focusing mirror and the nozzle are all completed manually. Therefore, a large manual error will be introduced, resulting in poor coupling effect, high requirements for the operator himself, and unstable coupling effect. In this case of processing, the spot may not all enter the nozzle, nor may it be exactly at the center of the nozzle, and it is very easy to burn out the nozzle, fail to achieve water-light coupling, and unable to process normally. At the same time, other parts in the coupling cavity may be damaged, and the water guide laser processing efficiency and quality are affected.

[0003] However, the alignment of the existing laser and the nozzle center mainly locates by using a CCD camera to photograph the laser spot and the nozzle, then adjusts the X and Y axes of the coupling device to move the nozzle center to the center of the spot, and finally fine-tunes by combining CCD imaging and the coupled power. During the alignment process, marking the center of the laser spot, and the movement of the focusing mirror and the nozzle are all completed manually. Therefore, a large manual error will be introduced, resulting in poor coupling effect, high requirements for the operator himself, and unstable coupling effect. In this case of processing, the spot may not all enter the nozzle, nor may it be exactly at the center of the nozzle, and it is very easy to burn out the nozzle, fail to achieve water-light coupling, and unable to process normally. At the same time, other parts in the coupling cavity may be damaged, and the water guide laser processing efficiency and quality are affected.

[0004] Therefore, a nozzle coupling device that can eliminate human factors, has a stable coupling effect, and higher processing efficiency is needed to solve the above technical problems. Summary of the Utility Model

[0005] The technical solution adopted by the present utility model to solve the technical problems is as follows: a system for adaptive coupling of a water-guided laser nozzle, comprising: a laser beam expander-focusing unit, a coupling unit, an observation system, a water supply system, and a three-dimensional workbench;

[0006] The laser beam expander-focusing unit is used to make the laser emitted by the laser pass through the beam expander unit and the reflecting mirror and then enter the focusing system, and then be focused by the focusing system near the nozzle orifice;

[0007] The coupling unit is used to couple the laser into the orifice of the nozzle and guide the laser to the processing surface through the nozzle;

[0008] The observation system is used to monitor the position and state of the laser at the nozzle orifice in real time;

[0009] The water supply system is used to provide high-pressure water flow to stabilize the water jet and control the length and stability of the water jet by adjusting the water pressure and the nozzle diameter;

[0010] The three-dimensional workbench is used to accurately move the workpiece or the nozzle to achieve the processing of complex shapes;

[0011] The laser beam expander-focusing unit is optically connected to the coupling unit, the observation system is optoelectronically connected to the coupling unit and the three-dimensional workbench, and the water supply system is hydraulically connected to the coupling unit.

[0012] Preferably, the coupling unit comprises: a reference model, a controlled object, a feedback controller, and an adaptive mechanism;

[0013] The reference model is used to provide the relative position parameters of the laser and the nozzle;

[0014] The feedback controller is used to adjust the controlled object after receiving information;

[0015] The adaptive mechanism is used to calculate and then re-feed the correct parameters back to the controller;

[0016] The controller is electrically connected to the reference model, the controlled object, and the adaptive mechanism respectively, and the reference model is electrically connected to the adaptive mechanism; the feedback controller includes two loops, an inner loop and an outer loop. The inner loop is a feedback loop composed of the controlled object and the controller, and the outer loop is a feedback loop composed of the adaptive mechanism and the controller. The parameters of the feedback controller are adjusted by the outer loop.

[0017] More preferably, the reference model is an example of high-quality alignment of a laser and a nozzle that has been debugged in the existing manner, and is a high-quality coupling model of a laser and a nozzle that meets the coupling rate.

[0018] The beneficial effects of the present utility model are:

[0019] The utility model can monitor in real time whether the laser deviates from the center of the nozzle during the processing, so as to avoid affecting the processing. If deviation is detected, the deviation signal e(t) will be quickly fed back to the controller. Therefore, the adaptive mechanism can be driven by e(t) to generate an appropriate adjustment effect, directly changing the parameters of the controller until this deviation approaches 0 infinitely, until the output of the system gradually approaches the output of the model infinitely, and the adaptive adjustment process will automatically stop, and the controller parameters will be automatically tuned. One adaptive coupling process can be completed, so that when the laser deviates from the center of the nozzle, it can be quickly aligned back. Therefore, the invention can effectively improve the service time of the nozzle, save costs, ensure the stability of processing, save time costs, and improve processing efficiency at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a system for adaptive coupling of a water-guided laser nozzle of the utility model;

[0021] Figure 2 is a control schematic diagram of the utility model;

[0022] Figure 3 is an imaging diagram of the alignment of the laser and the nozzle of the utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will clearly and completely describe the relevant technologies in the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0024] Reference Figures 1 to 3 , this embodiment mainly includes the following parts: a laser beam expander-focusing unit: the laser emitted by the laser passes through the beam expander unit and the reflector and then enters the focusing system, and then is focused near the nozzle orifice; a coupling unit and an observation system: the coupling unit couples the laser into the orifice of the nozzle and guides the laser to the processing surface through the nozzle. At the same time, the observation system can monitor the position and state of the laser in the nozzle orifice in real time; a water supply system: provides high-pressure water flow to stabilize the water jet and controls the length and stability of the water jet by adjusting the water pressure and the nozzle diameter; a three-dimensional workbench: is used to accurately move the workpiece or the nozzle to achieve the processing of complex shapes, such as Figure 1 shown.

[0025] Among them, the coupling unit includes: a reference model (including a sensor), a controlled object, a controller and an adaptive mechanism, as Figure 2As shown. This type of control system includes two loops: an inner loop and an outer loop. The inner loop is an ordinary feedback loop composed of a controlled object and a controller, and the parameters of the controller are adjusted by the outer loop. The main function of this system is to automatically adjust the controller according to the operating conditions of the system to adapt to the changes in the characteristics of the controlled object. It is applicable to a class of systems where the characteristics of the controlled object are unknown or the range of disturbance characteristics changes greatly, and at the same time, high performance indicators are required to be maintained frequently. When designing, it is not necessary to fully know the mathematical model of the controlled object. The specific operation steps are as follows:

[0026] Step 1: Select a high-quality coupling model of the laser and the nozzle that can meet our coupling rate as a reference, such as Figure 3 shown. The relative position parameters of the laser and the nozzle are called the reference model. For example, Figure 3 the center position of the light spot in is calibrated as (x1, y1), and the center of the light spot is set as (x2, y2) during actual processing. Conduct multiple model trainings on the system, which will result in high recognition accuracy.

[0027] Step 2: After the reference model is set, if the actual nozzle situation deviates from the reference model during actual processing, that is, x1≠x2, y1≠y2, use a sensor (such as a laser displacement sensor) to monitor the light spot position in real time and feed the data back to the controller for adjustment. The controller continuously receives the feedback signal from the sensor, calculates the deviation parameters Δx = x1 - x2, Δy = y1 - y2, and feeds the deviation parameters (Δx, Δy) back to the adaptive mechanism through the data bus.

[0028] Step 3: The controller will immediately drive the adaptive mechanism to use the bisection method to calculate and infinitely approximate the calibrated (x1, y1). By continuously narrowing the search range, gradually reduce the gap with the target position until the preset accuracy is reached.

[0029] Step 4: After adjustment, the controller re-obtains the new position of the light spot and compares it with the reference position to ensure that the position gradually approaches (x1, y1). One adaptive coupling process of the laser nozzle is successfully completed. Repeat the above steps to ensure the accurate positioning of the light spot.

[0030] In summary, the utility model can monitor in real time during the processing whether the laser and the nozzle deviate from the center, avoiding affecting the processing. If deviation is detected, the controller will automatically complete the tuning, so that when the laser deviates from the center of the nozzle, it can be quickly straightened back. Therefore, the present invention can effectively improve the service time of the nozzle, which can not only save costs, but also ensure the stability of processing, save time costs, and at the same time improve processing efficiency.

[0031] It should be emphasized that the above are only the preferred embodiments of the present utility model, and there is no restriction on the present utility model in any form. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. A system for adaptive coupling of a water-guided laser nozzle, characterized in that, Including: A laser beam expander - focusing unit, a coupling unit, an observation system, a water supply system, and a three - dimensional workbench; The laser beam expander - focusing unit is used to make the laser emitted by the laser enter the focusing system after passing through the beam expander unit and the reflector, and then be focused by the focusing system near the nozzle orifice; The coupling unit is used to couple the laser into the orifice of the nozzle and guide the laser to the processing surface through the nozzle; The observation system is used to monitor the position and state of the laser at the nozzle orifice in real time; The water supply system is used to provide high - pressure water flow to stabilize the water jet and control the length and stability of the water jet by adjusting the water pressure and the nozzle diameter; The three - dimensional workbench is used to accurately move the workpiece or the nozzle to achieve machining of complex shapes; The laser beam expander - focusing unit is optically connected to the coupling unit, the observation system is photoelectrically connected to the coupling unit and the three - dimensional workbench, and the water supply system is hydraulically connected to the coupling unit.

2. The system for adaptive coupling of a water-guided laser nozzle according to claim 1, wherein The coupling unit includes: a reference model, a controlled object, a feedback controller, and an adaptive mechanism; The reference model is used to provide the relative position parameters of the laser and the nozzle; The feedback controller is used to adjust the controlled object after receiving information; The adaptive mechanism is used to calculate and then re - feedback the correct parameters to the controller; The feedback controller is electrically connected to the reference model, the controlled object, and the adaptive mechanism respectively, and the reference model is electrically connected to the adaptive mechanism; the feedback controller includes two loops, an inner loop and an outer loop. The inner loop is a feedback loop composed of the controlled object and the controller, and the outer loop is a feedback loop composed of the adaptive mechanism and the controller. The parameters of the feedback controller are adjusted by the outer loop.

3. The system for adaptive coupling of a water-guided laser nozzle according to claim 2, characterized in that, The reference model is an example of a relatively high - quality alignment of the laser and the nozzle that has been debugged in the existing manner.

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