The Development of Neural Network Based System Identification ...

7.3 EXPERIMENTAL RESULTS 197
indicators that a full 4 DOF controller is realised using the proposed controller approach
with good compensation performance in all four motion axes.
Roll Angle (deg)
Pitch Angle (deg)
5
0
−5
0 100 200 300 400 500 600 700 800 900
Sample (k)
5
0
−5
0 100 200 300 400 500 600 700 800 900
Sample (k)
Yaw Angle (deg)
70
60
50
0 100 200 300 400 500 600 700 800 900
Sample (k)
Altitude (m)
0.1
0.08
0.06
0.04
0.02
0 100 200 300 400 500 600 700 800 900
Sample (k)
Figure 7.8 The control responses of the 4 DOF NNAPC controller with recursive NN training during
hovering flight test.
Table 7.7
The 4 DOF NNAPC controller response under hovering flight.
Outputs MSE Settling Time (s) Overshoot (%) Rise Time (s)
Pitch Angle, θ 0.17 n/a n/a n/a
Roll angle, φ 0.25 n/a n/a n/a
Yaw angle, ψ 1.54 n/a n/a n/a
Altitude, z 4.10 × 10 −6 0.76 1.69 0.38
7.3.3 Flight Controller Performance
In this subsection, the NNAPC controllers developed in this work are further tested
under the effect of parameter variations and input disturbances. There are several
parameters that can vary in the helicopter dynamics such as the changes in the payload