Research On Temperature Control System Of Bath Blackbody Radiation Source Based On ADRC

Blackbody radiation source is used as the standard facilities of contactless temperature measurement for the infrared thermometer and photoelectric pyrometer.Blackbody temperature is a very vital monitoring and control parameter in the course of the calibration.Too higher or lower temperature will affect the traceability and transmission of magnitude.In practice,it is strictly required that the temperature of the blackbody cavity as a standard source is maintained near the rated value(i.e.the given values).This subject requires a control algorithm to control different open diameter blackbody cavity in paper.The small open diameter cavity(35mm)is applied to low temperature surrounding depend on the semiconductor thermostat,its temperature control ranges from 0?to 50?,and the volatility of temperature is ±0.05?.The large open diameter cavity(80mm)is demanded its temperature ranges from 30? to 80? and the volatility of temperature is± 0.02 ?,which is based on the conventional microheaters to heating.The temperature control technologies of conventional blackbody radiation source have been stable,and the bath blackbody is main introduced in the paper.The external environment has a large impact on the blackbody,which makes its mathematical model difficult to establish.In addition,the temperature control system bath blackbody is a complicated process with inertia,time delay and nonlinearity,the PID controller is often used in industrial productions due to its simple and reliable structure,but it is difficult to obtain satisfactory control results in control accuracy and anti-interference capability.To solve the above problem,based on the analysis of the working principle and high-precision control of the bath blackbody,the active disturbance rejection control(ADRC)algorithm is applied to the temperature control system of the bath blackbody.First of all,this paper introduces the working principle and application of blackbody radiation source,which bases on the semiconductor refrigeration thermostat.The mathematical model is established of temperature control system of bath blackbody according to the working principle of the semiconductor refrigerator.Secondly,the ADRC control method is introduced to make simulation based on mathematical in MATLAB/Simulink software,which is compared with the traditional PID control algorithm.The simulation results show that proposed ADRC algorithm possessing fast response,high precision and positive setpoint tracking,it is better than PID control algorithm.Finally,the software and hardware experiment platform is designed,and the graphical programming of LabVIEW software is applied to realize the digital discretization of the ADRC algorithm.Based on NI's Compact RIO real-time controller as the hardware foundation,the ADRC control algorithm in thermostat blackbody temperature control is realized by LabVIEW software.When the temperature control system reaches stable working state,the target temperature of bath blackbody is lower than the ambient temperature,the error between thetemperature of the blackbody cavity measured by the temperature sensor and the target temperature does not exceed ±0.02?/30 min.When target temperature value is higher than the environment temperature,the error between the measured temperature value of the blackbody cavity and the target temperature does not exceed±0.01?/30 min.