Page 195 - Innovations in Intelligent Machines

State Estimation for Micro Air Vehicles 187
200
actual
100 estimated
φ (deg)
0

- 100

- 200
0 5 10 15 20 25

100
actual
estimated
50
θ (deg)
0

- 50
0 5 10 15 20 25
time (sec)
Fig. 6. Actual and estimated values of roll angle φ and pitch angle θ using simple
model inversion

not work well for attitude estimation during accelerated flight. Another idea
is to combine model inversion with the integral of roll and pitch as estimated
by the rate gyros.
Recalling that

˙
φ = p + q sin φ tan θ + r cos φ tan θ
˙
θ = q cos φ − r sin φ
and assuming that φ ≈ 0and θ ≈ 0weget
˙
φ = p
˙
θ = q.
Therefore we can integrate these equations to obtain an additional estimate
of φ and θ:
t
ˆ
φ int = p(τ) dτ
−∞
t

ˆ q(τ) dτ.
θ int =
−∞