Temperature control system for radiation calibration device of ultra-large-diameter infrared camera

Abstract

The invention provides a temperature control system for a radiation calibration device of an ultra-large-diameter infrared camera. The temperature control system comprises a meter-scale surface source blackbody radiation source, a temperature acquisition and control system, a heating plate group, a programmable power supply group, a low-temperature electromagnetic valve group, a liquid nitrogen supply system and an embedded control system, the temperature collection and control system collects the temperature of a radiation surface in real time through a temperature sensor and transmits the temperature to the control system, the temperature is compared with the set temperature, PID control is adopted, the refrigeration power and the heating power are controlled through two paths of output respectively, and the blackbody radiation source liquid nitrogen pipeline controls the meter-scale surface source blackbody radiation source through a plurality of low-temperature linear electromagnetic valves. The black body radiation source area is refrigerated; the programmable power pack controls the heating plate group to heat the blackbody radiation source area; the embedded control system realizes input and output of data, realization of a control strategy and remote transmission and communication of the data. The system can perform high-precision control and rapid measurement on the temperature of the black body, and improves the uniformity and stability of the meter-scale surface source black body.

Description

Technical Field

[0001] The invention relates to the design of a high-precision temperature control system for a meter-level surface source blackbody, and belongs to the field of electrical control. Background Art

[0002] With the development of technology, meter-level surface source black bodies are increasingly used as standard infrared light sources in the aerospace field and infrared imagers, including early warning systems, infrared guidance strike systems, infrared remote sensing systems, etc. During the development, production, and testing of these infrared imagers, accurate radiation calibration and performance testing must be performed on the infrared imagers using meter-level surface source black bodies according to the working environment of the system to obtain accurate calibration coefficients, accurately grasp the various performance indicators of the infrared imagers, and ensure that their performance indicators reach the pre-designed values.

[0003] And as the aperture of infrared imagers continues to increase, the effective area requirements of meter-level surface source blackbodies are also increasing. The current temperature control method used on conventional-sized blackbodies cannot meet the technical indicators of meter-level surface source blackbodies. Therefore, in order to ensure that the temperature accuracy, uniformity and stability of the surface source blackbodies used in infrared imagers and payloads can meet the use requirements, it is necessary to design the temperature control method and temperature monitoring method of meter-level surface source blackbodies. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a temperature control system for an ultra-large aperture infrared camera radiation calibration device, namely, a high-precision meter-level surface source blackbody temperature control system. The system can perform high-precision control and rapid measurement of the temperature of the blackbody, thereby reducing the temperature deviation of the meter-level surface source blackbody and improving the uniformity and stability of the meter-level surface source blackbody.

[0005] The invention comprises a meter-level surface source blackbody radiation source, a temperature acquisition and control system, a heating plate group, a programmable power supply group, a low-temperature electromagnetic valve group, a liquid nitrogen supply system, and an embedded control system;

[0006] The temperature acquisition and control system acquires the temperature of the radiation surface in real time through a temperature sensor and transmits it to the control system, compares it with the set temperature, and adopts PID control. The cooling and heating powers are controlled respectively through two outputs. The liquid nitrogen pipeline of the blackbody radiation source controls the meter-level surface source blackbody radiation source through a plurality of low-temperature linear solenoid valves to realize the cooling of the blackbody radiation source area; the programmable power supply group controls the heating plate group to realize the heating of the blackbody radiation source area; the embedded control system realizes the input and output of data, the realization of control strategy and the remote transmission and communication of data.

[0007] The temperature collection and control system is realized by networking several sets of temperature control panels.

[0008] The temperature acquisition and control system acquires the blackbody radiation surface temperature and the ambient temperature in real time, and uploads them to the embedded control system through the RS485 communication interface. The embedded control system formulates a control strategy according to the set temperature and transmits it to the temperature control instrument group. The temperature control instrument group controls the power output of the programmable power supply.

[0009] An electromagnetic relay is added to the front end of the program-controlled power supply, and the on and off of the program-controlled power supply is controlled by controlling the closing of the relay.

[0010] Beneficial effects:

[0011] The invention has the functions of heating power control of the heating plate, flow control of the refrigerator, real-time collection of the temperature of the radiation surface, etc., and can realize the heating and cooling control of the meter-level surface source black body, as well as the heating power output. The characteristics of the temperature control system are: high temperature control accuracy of the black body radiation surface, fast temperature rise rate, high temperature stability, and high temperature uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The included drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification, and are used to list the embodiments of the present invention and together with the written description, to explain the principles of the present invention.

[0013] Figure 1 The working principle diagram of the present invention is

[0014] Figure 2 The schematic diagram of the control system in the present invention is

[0015] Figure 3 This is the embedded component block diagram of the present invention DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention will be described in detail below.

[0017] The invention comprises a meter-level surface source blackbody radiation source, a temperature collection and control system, a heating plate group, a program-controlled power supply group, a low-temperature electromagnetic valve group, and a liquid nitrogen supply system.

[0018] The large surface source blackbody is heated by a resistive heater, cooled by liquid nitrogen (natural radiation and convection under laboratory conditions), and controlled by a high-precision PID closed-loop control. Figure 1As shown, the temperature sensor collects the temperature of the radiation surface in real time and transmits it to the temperature control system, which is compared with the set temperature. PID control is adopted to control the cooling and heating power through two outputs respectively. The blackbody radiation source liquid nitrogen pipeline controls the meter-level surface source blackbody radiation source through several low-temperature linear solenoid valves to achieve regional cooling of the blackbody radiation source. The programmable power supply group controls the heating plate group to achieve regional heating of the blackbody radiation source. The precise closed-loop control of the system is achieved, and the self-tuning and continuous learning functions of the temperature control system are used to meet the system's fast and stable temperature control requirements in a vacuum environment.

[0019] Since the meter-level surface source blackbody has a large area, it requires a large heating power. It is composed of multiple control cabinets (main control cabinet and several heating cabinets). The control cabinets are connected by signal transmission lines, and the power output of each control cabinet is controlled by the signal transmission lines. The main control cabinet has a sensor temperature measurement cable, which is connected to the blackbody radiation source through the electrical flange on the vacuum chamber to realize the data collection of the temperature sensor. In addition, it is a liquid nitrogen valve control cable for controlling the liquid nitrogen flow. The main control cabinet has a heating control signal output cable for controlling the heating power of the heating cabinet. Each heating cabinet has a heating control signal output cable to receive the heating power control signal from the main control cabinet. The heating cabinet adjusts the heating power according to the control signal to control the blackbody temperature.

[0020] The main control cabinet mainly includes an embedded control system and a temperature acquisition and control system. The embedded control system mainly realizes data input and output, the implementation of control strategies, and remote data transmission and communication; the temperature acquisition and control system mainly realizes the real-time temperature acquisition and temperature control of the black body radiation source, which is mainly achieved through the networking of multiple sets of temperature control panels.

[0021] The main function of the temperature acquisition and control system is to collect the blackbody radiation surface temperature and ambient temperature in real time through the electrical connection cable, and upload it to the embedded control system through the RS485 communication interface. The embedded control system formulates a control strategy based on the set temperature and transmits it to the temperature control instrument group. The temperature control instrument group controls the power output of the programmable power supply, thereby adjusting the blackbody heating power to achieve blackbody temperature stability. The temperature control network module is mainly composed of a temperature control instrument group.

[0022] In order to ensure the uniformity of blackbody control, refined control is required. Therefore, each heating film is divided into 6 loads, and 6 programmable power supplies are controlled by a temperature controller to control the electric power applied to the 6 loads respectively. In order to ensure that the electric power of the six loads can be adjusted separately and at the same time ensure the driving ability of the single output signal of the temperature controller, a one-to-six signal conditioning circuit board is required between the temperature controller and the six programmable power supplies to condition the output signal of the temperature controller.

[0023] In order to prevent the current of the total circuit of the control system from being too large at the moment of power-on, it is necessary to control each programmable power switch. Therefore, an electromagnetic relay is added to the front end of each programmable power supply to control the on and off of the programmable power supply by controlling the closing of the relay. The relay control circuit mainly controls the closing of the relay through the output voltage of the power supply part. When the system is powered on, the relay is closed and the programmable power supply is turned on. The programmable power switch control module can be mainly divided into two parts: AC-DC voltage conversion and relay control. The main function of the power supply circuit is to convert the input 220V AC voltage into 12V DC voltage to provide power for the relays and other devices on the entire circuit board.

[0024] Main technical indicators of meter-level surface source blackbody:

[0025] 1. Covered spectral range: 2.5μm~5.5μm, 8μm~14μm;

[0026] 2. Effective caliber: ≥4.5m×4.5m;

[0027] 3. Equipment center height: To be determined;

[0028] 4. Blackbody temperature: 150K~400K (continuously adjustable) @ vacuum low temperature environment;

[0029] a) Room temperature ~ 400K (continuously adjustable) @ laboratory environment;

[0030] 5. Average temperature rise and stabilization time: ≤10K / 30min@laboratory environment;

[0031] 6.≤10K / 90min@vacuum low temperature environment;

[0032] 7. Temperature stability: ≤±0.1K / 15min;

[0033] 8. Blackbody temperature uniformity: (within 90% effective radiation aperture);

[0034] 1. Better than 1.5K@150K≤T<240K;

[0035] 9. Better than 1.0K@240K≤T<280K;

[0036] 10. Better than 0.5K@280K≤T≤400K;

[0037] 11. Normal emissivity: 0.98±0.01;

[0038] 12. Temperature measurement accuracy: ≤±0.1K;

[0039] 13. Cooling method: liquid nitrogen refrigeration.

[0040] The many features and advantages of these embodiments are apparent from this detailed description, and thus the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not intended that the embodiments of the invention be limited to the exact construction and operation illustrated and described, but rather all suitable modifications and equivalents falling within the scope thereof are intended to be covered.

[0041] Parts of the present invention that are not described in detail are well known to those skilled in the art.

Claims

1. A temperature control system for a radiation calibration device for an ultra-large aperture infrared camera, characterized in that It includes meter-level surface source blackbody radiation source, temperature acquisition and control system, heating plate group, programmable power supply group, low-temperature solenoid valve group, liquid nitrogen supply system, and embedded control system; The temperature acquisition and control system acquires the temperature of the radiation surface in real time through a temperature sensor and transmits it to the control system, compares it with the set temperature, and adopts PID control. The cooling and heating powers are controlled respectively through two outputs. The liquid nitrogen pipeline of the blackbody radiation source controls the meter-level surface source blackbody radiation source through a plurality of low-temperature linear solenoid valves to realize the cooling of the blackbody radiation source area; the programmable power supply group controls the heating plate group to realize the heating of the blackbody radiation source area; the embedded control system realizes the input and output of data, the realization of control strategy and the remote transmission and communication of data.

2. The temperature control system according to claim 1, characterized in that The temperature collection and control system is realized by networking several sets of temperature control panels.

3. The temperature control system according to claim 1, characterized in that The temperature acquisition and control system acquires the blackbody radiation surface temperature and the ambient temperature in real time, and uploads them to the embedded control system through the RS485 communication interface. The embedded control system formulates a control strategy according to the set temperature and transmits it to the temperature control instrument group. The temperature control instrument group controls the power output of the programmable power supply.

4. The temperature control system according to claim 1, characterized in that An electromagnetic relay is added to the front end of the program-controlled power supply, and the on and off of the program-controlled power supply is controlled by controlling the closing of the relay.

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