An anti-surge control system of a certain turbofan engine is taken as an object

the dynamical mathematical model of this system has been developed and the simulation has been done on a digital computer. In the first step of the simulation the linear system is studied and the dynamical performances are calculated under four conditions

thereby the main influencing parameters of the dynamical performances are obtained. In the second step

the effects of nonlinearities of the dead-region and the backlash on the dynamical performances are studied. The digital simulation results indicate that the effects of two nonlinearities on the performances are opposite. The former enhances the relative stability of the system

but the latter reduces that. Both effects appear not to be in agreement with the superposition principle. Finally

the ways of improving the quality of the system are presented based on the results of the calculations.