Tham khảo tài liệu 'advances in flight control systems part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Autonomous Flight Control System for Longitudinal Motion of a Helicopter 207 b polytopic models Fig. 5. v-gap metric 208 Advances in Flight Control Systems H cost Fig. 6. H-2 cost Evaluation of design models According to Section three linear interpolative polytopic models were obtained. Table 2 shows the operating points chosen for the models. While the design points Vd of three LTI models are shown in Table 3. The v-gap metric is one of criteria measuring the model error in the frequency domain. It had been introduced in robust control theories associated with the stability margin Vinnicombe 2001 . The v-gap metric between two LTI models P1 s and P2 s is defined as v P1 P2 11 1 P2 Pỉ -1 2 P1 - P2 I P1P 1 2 - 40 The range is ỗv G 0 1 . A large ov means that the model error is large. The v-gap metric is used for evaluating the model Ppoiy V and Piti Vd . Figure 5 shows v-gap metric between Piti Vd and Pipv V and between Ppoiy V and Pipv V . ờv Piti V Pipv Vd was rapidly increased when V was shifted from Vd. On the other hand the maximum of bv Ppciy V Pipv V was reduced according to the number of the operating points. It was seen that Ppoiy V appropriately approximated Pipv V over the entire range of the flight velocity. Design of F and H2 cost The design parameters for designing F in Eq. 30 were given as follows. B1 0 0 C1 02x5 D1 05x2 I2 Autonomous Flight Control System for Longitudinal Motion of a Helicopter 209 h m x m e. e deg u m s f 19 0 1 gJ Fixed-SF 1 0 50 100 150 0 50 100 150 2---------------1------------ 0 50 100 150 t s a Controlled variables and inputs b Positions Fig. 7. Time responses using Ffix
