4
Chapter 1. Introduction
G
ain (dB)
20
0
40
60
–20
10
2
10
1
10
3
10
4
10
5
10
6
10
7
Fourier frequency [Hz]
Inte
grato
r
Double in
teg
rat
or
Proportional
High fr
eq
. cut
off
Diff
eren
tia
tor
Inte
grato
r
10
8
FAST LF GAIN (limit)
FAST
GAIN
DIFF GAIN (limit)
FAST INT
FAST DIFF
SL
OW INT
Filt
er
Figure 1.3:
Conceptual Bode plot showing action of the fast (red) and
slow (blue) controllers. The slow controller is either a single or double
integrator with adjustable corner frequency. The fast controller is
PID
with adjustable corner frequencies and gain limits at the low and high
frequencies. Optionally the differentiator can be disabled and replaced
with a low-pass filter.
