Abstract:
It is strong coupling between the total temperature, Mach number and stagnation pressure in cryogenic wind tunnel. Moreover, the flow filed is susceptible to external interference and its accurate mathematical model is difficult to be obtained. Thus it is difficult to design a high performance flow filed controller for the cryogenic wind tunnel. The active disturbance rejection control (ADRC) has some advantages, such as not relying on the accurate mathematical model, strong anti-interference ability, simple algorithm for engineering applications and so on. So a flow control strategy for the cryogenic wind tunnel is designed based on the ADRC theory. According to the principle of the ADRC, all the coupling between the total temperature, total pressure and Mach number, the modelling errors, the parameter perturbation of the flow field, and the external disturbance etc, can be regarded as total disturbance. The total disturbance is estimated by a extended state observer (ESO) and compensated by a feed-forward control. On the one hand, the decoupling control of the total temperature, total pressure and Mach number is realized; on the other hand, the anti-interference ability of the flow field is improved. Taking NASA 0.3m TCT wind tunnel as the research object, the flow field ADRC control model was built on Matlab/Simulink platform for simulation analysis. The results show that the ADRC can achieve good decoupling control of the total temperature, total pressure and Mach number, maintain good control performance under the condition of large perturbation of system parameters, and show good anti-interference ability.