National Instruments 370757C-01 用户手册

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Chapter 4
Controller Synthesis
4-22
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10. Compute the closed-loop system for the reduced order plant and the 
frequency-shaped compensator:
[Sysfs_scl]=feedback(Sysr,Sysfs_sc);
poles(Sysfs_scl)
ans (a column vector) =
  -0.645263 + 0.587929 j
  -0.645263 - 0.587929 j
  -0.500025 + 0.866011 j
  -0.500025 - 0.866011 j
  -0.347592 + 1.09155  j
  -0.347592 - 1.09155  j
11. Compute the closed-loop system for the full-order plant and the 
frequency-shaped compensator.
Sysfs_scl_fo = feedback(Sys,Sysfs_sc);
poles(Sysfs_scl_fo)
ans (a column vector) =
  -0.690216  + 0.522898 j
  -0.690216  - 0.522898 j
  -0.419783  + 0.892632 j
  -0.419783  - 0.892632 j
  -0.381722  + 1.10668  j
  -0.381722  - 1.10668  j
  -0.0261589 + 5.00027  j
  -0.0261589 - 5.00027  j
The full-order closed-loop system is stable. The open-loop eigenvalues 
of the unmodelled mode have not moved much, which is a sign of good 
robustness. The eigenvalue of the unmodelled mode changed from 
–.0250 
± 5to  –0.0262 ± 5j.
Loop Transfer Recovery (lqgltr)
Loop transfer recovery (LTR) is fully described in references [KS72, 
DoS79,DoS81,SA88]. The properties of the recovery pertain to the LQG 
feedback system as shown in Figure 4-8. 
The parameter 
ρ (
rho
) can be manipulated by the user to obtain loop 
transfer recovery through the regulator (
lqrltr
) or the estimator 
(
lqeltr
).