Fig. 1

Structure of GTF engine

Fig. 2

Standard feedback control structure diagram

Fig. 3

Geometric design method schematic diagram in complex plane

Fig. 4

Optimal/suboptimal performance for ηyd and ηzid in complex plane

Fig. 5

Robust controller design scope in complex plane

Fig. 6

Different controller performances described in complex plane

Fig. 7

GDM controller design process

Fig. 8

Frequency domain analysis of transfer function from disturbance to outputs

Fig. 9

Normalized Mach number disturbance spectrum

Fig. 10

GDM controller design area on complex plane

Table 1

Design ηyd and ηzd under different single frequency

Fig. 11

Disturbance rejection performance of GDM controller under different single frequency

Table 2

Realistic performances and transfer functions designed by GDM under different single frequency

Fig. 12

Comparison of ηyd frequency domain characteristics among different GDM controllers

Fig. 13

Comparison of ηzd frequency domain characteristics among different GDM controllers

Fig. 14

Time domain characteristics of corrected fan speed under different GDM controllers

Fig. 15

Time domain characteristics of thrust under different GDM controllers

Table 3

Comparison of disturbance rejection performances among GDM controllers designed in different frequency

Fig. 16

Frequency characteristics of weight function and Tzw in mixed sensitivity H∞ controller

Fig. 17

Comparison of ηyd frequency domain characteristics between H∞ and GDM controller

Fig. 18

Comparison of ηzd frequency domain characteristics between H∞ and GDM controller

Fig. 19

Time domain characteristics of corrected fan speed under H∞ and GDM controllers

Fig. 20

Time domain characteristics of thrust under H∞ and GDM controller

Table 4

Comparison of controller disturbance rejection performance under different cruise steady-state points