A laser heating and temperature control device for confined spaces and a control method thereof

Abstract

The application belongs to the technical field of laser application equipment in thermal parameters, and provides a narrow space laser heating and temperature control device and a control method thereof, which can perform high-temperature heating on the material surface inside the narrow space of a missile such as an electric antenna cover, a fairing or an instrument cabin, can complete multiple parameter test tasks in cooperation with other thermal and optical test devices, and has an excellent application prospect. By adopting a non-confocal multi-fiber laser heating technology and combining a miniaturized and integrated water-cooled sleeve pipe circular collimating mirror design, a technical problem of uniformly and efficiently heating the material surface inside the narrow space such as an antenna cover, a fairing or an instrument cabin is successfully solved.

Description

Technical Field

[0001] This invention belongs to the technical field of laser application equipment in thermal parameters, specifically relating to a laser heating and temperature control device and its control method in a confined space. Background Technology

[0002] The confined space laser heating and temperature control device uses multiple optical fibers to transmit the laser energy generated by the laser to a front-end collimating lens, forming a laser beam that irradiates the surface of the sample to be heated. The sample surface absorbs the radiation energy from the laser beam, causing its temperature to rise rapidly. During the heating process, infrared thermocouples are used to collect the temperature of the heated sample surface and feed it back to the control module. The control module receives the signal, performs PID temperature control, and adjusts the output power of the laser heating section in real time.

[0003] In related technologies, laser heating devices typically heat sample surfaces in large indoor spaces, with heating distances exceeding 500mm. This makes them unsuitable for heating in confined spaces smaller than 400cm³, such as radomes, fairings, or instrument compartments. The collimating mirrors in laser heating devices lack water cooling and can only withstand temperatures up to 150℃. However, in confined spaces, low-emissivity materials reflect significant energy during heating, raising the surrounding air temperature to over 200℃. Therefore, a water-cooling sleeve is needed on the collimating mirror surface to reduce temperature. Furthermore, to ensure uniform heating surface, collimating mirrors are often designed in a square shape for even laser distribution. However, this square design results in excessive size, limiting space when shared with other measuring devices in confined spaces. Finally, laser heating devices lack temperature control components, requiring the installation of thermocouples or platinum resistance thermometers on the sample surface for temperature feedback and manual power adjustment. Moreover, only single-temperature heating settings are possible, not automatic control of multiple temperatures, leading to excessively long manual processing times. Heating in confined spaces cannot be controlled if the sample surface conditions are not suitable for installing a thermometer. Summary of the Invention

[0004] In view of this, the present invention provides a laser heating and temperature control device and control method for confined spaces, which can heat the surface of materials inside confined spaces of missiles such as electrical antenna covers, fairings or instrument compartments at high temperatures. When used in conjunction with other thermal and optical testing devices, it can complete multiple parameter testing tasks and has excellent application prospects.

[0005] To achieve the objectives of this invention, the following technical solutions are provided.

[0006] A laser heating and temperature control device for confined spaces according to the present invention A laser heating and temperature control device for confined spaces, comprising: A laser controller is used to generate and output laser light. The collimating lens fiber assembly has its input end optically connected to the laser controller, and is used to transmit and collimate the laser generated by the laser controller to form a heated spot on the sample surface. A temperature control device is used to acquire temperature signals from the sample surface and, based on the deviation between the set target temperature and the acquired temperature signals, outputs control signals to the laser controller using a composite control algorithm to adjust its output power. A cooling system is used to circulate and cool the laser controller and the collimating lens fiber optic assembly.

[0007] The laser controller includes multiple independent laser driving channels, each driving one optical fiber. The collimating lens fiber assembly adopts a non-confocal multi-fiber design, which can output multiple light spots to form a uniform heating area on the sample surface.

[0008] The collimating lens of the collimating lens fiber assembly is a circular structure and is integrated with a water-cooling sleeve.

[0009] The temperature control device includes an infrared thermocouple and a PID control module. The composite control algorithm is as follows: when the temperature deviation is greater than a first threshold, fixed-value control is used; when the temperature deviation is less than or equal to the first threshold and greater than a second threshold, fuzzy control is used; and when the temperature deviation is less than or equal to the second threshold, traditional PID control is used.

[0010] The cooling system includes a water-cooled unit, a water pump, and a circulation pipeline. The circulation pipeline is connected to the water-cooled plate inside the laser controller and the water-cooled sleeve of the collimating lens fiber optic assembly.

[0011] This invention proposes a method for laser heating and temperature control in confined spaces, implemented based on the device described in this invention, comprising the following steps: Start the refrigeration system to cool down; Power the temperature control device and the laser controller; Set the target temperature and maximum output current percentage in the control software; Turn on the laser controller output to dynamically adjust the output power based on the signal fed back from the temperature control device.

[0012] Beneficial effects (1) The device of the present invention can solve the problem that it is difficult to heat the surface of materials inside the narrow space of electrical appliances such as antenna covers, fairings or instrument compartments at high temperatures. It has the characteristics of fast heating rate, small temperature fluctuation, uniform heating area and small size. It can heat the temperature range of 40mm in diameter from 50℃ to 500℃.

[0013] (2) Based on the need for high-temperature on-site heating in the narrow space of electrical appliances such as radomes, fairings or instrument compartments, this invention can rapidly, stably and uniformly heat materials in different locations within the narrow space. The non-confocal multi-fiber laser heating technology and automatic heating power control adopted by the narrow space laser heating and temperature control device can perfectly solve the problem of heating in narrow spaces below 500℃.

[0014] (3) This invention integrates an intelligent temperature control device. The device adopts non-contact temperature feedback based on infrared radiation temperature measurement and combines a composite control algorithm of setpoint control, fuzzy control and traditional PID control. This control strategy combines the advantages of fast response, overshoot suppression and precise steady-state adjustment, realizing automated control of the heating process. It eliminates the need to install contact temperature measuring elements on the sample surface, making it particularly suitable for sample surfaces where it is not appropriate to install thermometers. This significantly reduces manual intervention and time costs, and enables automatic program control of multiple temperature points.

[0015] (4) The entire device of this invention is equipped with a highly efficient and reliable cooling system, which actively cools the core laser components and key parts such as the collimating lens, ensuring that the equipment can work stably for a long time in harsh environmental temperatures of up to 200°C or higher, preventing equipment damage caused by the accumulation of reflected energy, and also effectively reducing the interference of background thermal radiation on the measurement, thereby improving the reliability and testing accuracy of the entire system. It can realize the power output control when using a confined space laser heating and temperature control device to heat dense, opaque, high-temperature sintered silicon carbide materials at high temperatures of 100~350°C. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the heating and control principle of the device of the present invention.

[0017] Figure 2 A schematic diagram of the temperature control device of the present invention.

[0018] Figure 3 A schematic diagram of the temperature control device of the present invention.

[0019] Figure 4 This is a schematic diagram of the refrigeration system of the present invention.

[0020] Figure 5 is a schematic diagram of the water-cooled housing of the present invention. In Figure 5(a), the fiber optic collimating lens is shown, and in Figure 5(b), the temperature probe is shown. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] This invention proposes a laser heating and temperature control device for confined spaces, and the heating and control principle diagram is shown below. Figure 1As shown, the system includes a laser controller, a collimating lens fiber, a temperature control device, and a cooling system. The laser controller can generate laser light manually or automatically. The collimating lens controls the optical path of the laser light generated by the controller, causing the heating system to produce seven non-confocal light spots to ensure the uniformity of the heated light spots as much as possible. The temperature control device has a built-in temperature measurement and PID control module, which can adjust and control the heating power of the laser to keep the heating temperature dynamically balanced at the target temperature.

[0023] Specifically, the control panel of the laser controller includes a power switch, a heating power display screen, a heating power control knob, an indicator light switch, water-cooling inlet and outlet pipes, a control interface, a control switch, an RS232 data transmission interface, a network cable interface, an Inteilock lock, a power cord, and other electrical interfaces or buttons. Internally, the laser controller contains seven constant current source driver boards, which include functions such as positioning indicator light control, laser drive control circuitry, constant voltage source to constant current source conversion, and water-cooling temperature testing; seven LED laser triggers, producing a laser array effect; and seven switching power supplies, which provide a constant voltage source to the laser by connecting to a 220V voltage. The constant current source driver boards and LED laser triggers are fixed on a water-cooling plate for cooling to prevent damage from overheating. In this embodiment, the main technical specifications of the laser controller are: heating temperature range: 50℃~500℃; effective heating area: diameter 40mm; heating rate: ≥30℃ / min; temperature uniformity: 5%.

[0024] One side of the collimator is connected to an optical fiber, while the other side outputs the laser. The heating fiber is a DBR-type fiber based on a Bragg grating, which has high laser efficiency and stable single-mode operation characteristics. The laser resonant cavity consists of a 1-2 cm long rare-earth-doped fiber fused between a pair of fiber gratings. The pump light is coupled into the cavity through a wavelength division multiplexer at the input end, and the remaining pump light is filtered out by another wavelength division multiplexer at the output end to obtain the signal laser output. This short cavity structure ensures that the laser has a large longitudinal mode spacing, thus achieving single-mode operation of the laser under the narrow-band filtering effect of the fiber grating. The total length of the heating fiber is 2 m, and the diameter is 60 mm. Considering the limited space inside the radome, the size of the fiber collimator was minimized as much as possible during its design.

[0025] The temperature control device primarily uses temperature feedback obtained from infrared thermocouple radiation measurement to regulate the power of the laser controller. Fuzzy PID automatic adjustment is possible by setting a temperature value. A composite control technology combining fuzzy algorithms and PID control is employed to ensure excellent dynamic performance and control accuracy of the radiant heat source. The basic principle of this control technology is as follows: when the laser heating temperature exceeds a certain threshold, a customized control mode is used to improve the system's response speed and accelerate the response process; when the deviation decreases to the threshold, it switches to fuzzy control mode to improve the system's damping performance and reduce overshoot during the response process, combining the advantages of setpoint control and fuzzy control. When the deviation enters the steady-state equilibrium region of fuzzy control, the system switches to traditional PID control mode. PID control has an ideal adjustment effect within a small range near the equilibrium point, and its integral action can ultimately eliminate the system's steady-state error. The principle of the temperature control device is as follows: Figure 2 As shown, the interface of the temperature control device is as follows: Figure 3 As shown.

[0026] The cooling system provides circulating cooling for the laser controller, infrared thermocouples, and collimating lens in the measuring device through both high-efficiency water cooling and air cooling. This prevents damage to the instruments due to high temperatures and also prevents interference from radiation signals generated by heat conduction at locations other than the testing position. The principle of the cooling system is as follows: Figure 4 As shown, a water pump provides the power for water circulation. Two cooling water streams from the water-cooled unit enter the laser controller and collimator lens respectively for cooling. The water is then circulated back to the water-cooled unit via the pump. A temperature sensor is installed in the water-cooling pipe in the middle to test the water temperature. The temperature feedback signal is used for PID control of the power of the water-cooled unit. In addition, two fixtures, a fiber optic collimator lens and a temperature probe, were designed independently. The internal water-cooled circulation prevents the equipment from being burned out by high temperature. The back of the outer casing is connected to the inlet and outlet water pipes via valves, as shown in Figure 5. Figure 5(a) shows the fiber optic collimator lens, and Figure 5(b) shows the temperature probe.

[0027] This invention proposes a method for laser heating and temperature control in confined spaces. Based on the control device of this invention, after setting up the infrared thermocouple and collimating lens, ensuring their focal points converge at the same measurement location, and verifying that the connection is correct, heating can begin. The specific steps are as follows: Step 1: Pour in cooling water and turn on the water-cooled unit; Step 2: Power the temperature control device, laser controller, and computer in sequence; Step 3: Enter the target temperature value in the computer software and click "Set Target Temperature"; Step 4: Enter the maximum current percentage in the computer software, check "Output or All Channels Output", and click "Settings or All Channels Settings". Each channel controls the output power of one fiber optic cable, and the maximum current percentage and output power percentage are exactly the same. Step 5: Turn the control switch of the laser controller to "on" and wait for three seconds to output radiation energy. At this time, the output power will generate a corresponding value and be dynamically adjusted.

[0028] This invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered within the scope of protection of this invention.

Claims

1. A laser heating and temperature control device for confined spaces, characterized in that, include: A laser controller is used to generate and output laser light. The collimating lens fiber assembly has its input end optically connected to the laser controller, and is used to transmit and collimate the laser generated by the laser controller to form a heated spot on the sample surface. A temperature control device is used to acquire temperature signals from the sample surface and, based on the deviation between the set target temperature and the acquired temperature signals, outputs control signals to the laser controller using a composite control algorithm to adjust its output power. A cooling system is used to circulate and cool the laser controller and the collimating lens fiber assembly.

2. The confined space laser heating and temperature control device according to claim 1, characterized in that, The laser controller includes multiple independent laser driving channels, each driving one optical fiber. The collimating lens fiber assembly adopts a non-confocal multi-fiber design, which can output multiple light spots to form a uniform heating area on the sample surface.

3. The confined space laser heating and temperature control device according to claim 2, characterized in that, The collimating lens of the collimating lens fiber assembly has a circular structure and is integrated with a water-cooling sleeve.

4. The confined space laser heating and temperature control device according to any one of claims 1-3, characterized in that, The temperature control device includes an infrared thermocouple and a PID control module. The composite control algorithm is as follows: when the temperature deviation is greater than a first threshold, fixed-value control is used; when the temperature deviation is less than or equal to the first threshold and greater than a second threshold, fuzzy control is used; and when the temperature deviation is less than or equal to the second threshold, traditional PID control is used.

5. The confined space laser heating and temperature control device according to claim 1, characterized in that, The cooling system includes a water-cooled unit, a water pump, and a circulation pipeline. The circulation pipeline is connected to the water-cooled plate inside the laser controller and the water-cooled sleeve of the collimating lens fiber optic assembly.

6. A method for laser heating and temperature control in a confined space, implemented based on the apparatus described in any one of claims 1 to 5, characterized in that, Includes the following steps: Start the refrigeration system to cool down; Power the temperature control device and the laser controller; Set the target temperature and maximum output current percentage in the control software; Turn on the laser controller output to dynamically adjust the output power based on the signal fed back from the temperature control device.

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