Residual Error Integral Predictor-Based Smith Fuzzy PID Temperature Controller for Thermal Vacuum Test

Thermal vacuum test is an important procedure in the development of spacecraft and load. Due to the various layouts of heaters and temperature sensors for kinds of devices under test (DUTs), the temperature responses during heating process are not same. The thermal vacuum test is the universal experiment aimed at different devices, that the temperature control algorithm of test cannot be optimized for each test. These factors would cause temperature overshoot and multiple oscillations near the preset value during test, that may damage DUTs. This article proposes an anti-windup Smith fuzzy proportional-integral-derivative (PID) temperature controller based on residual error integral predictor. The Smith fuzzy PID (FPID) controller could automatically tune the controller’s coefficients and reduce the impact of time delay. On this basis, two steps are taken to suppress the overshoot in temperature control. First, the fuzzy rules are optimized to refine the tuning process of fuzzy logic at different error stages. Then, by predicting the error integral in the remaining heating time, the original integral term of the controller is replaced to resist the integral saturation. In addition, a miniaturized multichannel temperature acquisition device has been designed, which could be installed at the front end of the signal link, closer to the sensors, thereby reducing interference during signal transmission. Through extensive simulations, the proposed method outperforms traditional temperature control methods in the stages of heating and cooling. After verification by a real thermal vacuum test, the proposal can effectively suppress overshoot in temperature control under vacuum conditions, and also quickly stabilize the temperature near the set value, further reducing the impact of overshoot on the load.