Research on a Dual-Closed-Loop Temperature Control Method and System Based on Dual Sensors for Infrared Object Simulation

To evaluate the detection and recognition ability of infrared imaging systems in the field, it is necessary to establish a high-precision infrared simulation system that can generate multiple object types. Therefore, a dual-closed-loop temperature control method and system for high-precision infrared objects based on dual sensors are developed. First, the heat exchange model of infrared target system is established by studying the mechanism of infrared radiation. Second, an ADT7420 digital sensor and a Pt100 analogue sensor are used as dual sensors, in which the temperature measurement results of the digital sensor are used as a coarse reference, and then the temperature measurement results of the analogue sensor are used to achieve fine adjustment. Third, a predictive proportional-integral- derivative (PID) control algorithm for real-time tuning of online parameters is designed in detail, and online information control based on dual sensors is realized once. The temperature is calibrated based on a high-precision infrared thermal imager to realize secondary control of the temperature information, thereby forming internal and external dual-closed-loop temperature measurement control. The specific performance is as follows: in the inner closed loop, the main control computer realizes the temperature control of the heater by controlling the target element controller, and the temperature control situation is displayed on the main control computer. In the outer closed loop, the temperature data of each target element are collected by a high-precision infrared camera, and the target system is calibrated in real time by the master control computer. Finally, the system is verified by comprehensive experiments. The results show that the applicable temperature range of the system is −15 ~ +50 °C. The temperature control accuracy is ≤ 0.5 °C, and the repeatability error is less than 1.5% within the ambient temperature ±10 °C. The system control period is less than 60 s when the temperature difference is 2 °C. The system can simulate large-area and high-precision infrared targets in the field environment. It can be remotely controlled by computer terminals. Point or surface objects can be generated as needed in the system. At the same time, the system can continue to expand the number of target elements to achieve larger and more complex object targets, which has important engineering application value.