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Thesis - Leigh Moody.pdf - Bad Request - Cranfield University

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Appendix H / Steady State Tracking Filters<br />

_ _<br />

X ˆ<br />

X ˆ&<br />

X ˆ &<br />

⎛<br />

2<br />

2<br />

⎜ ω ⋅<br />

( ) ( 2 ⋅ s + 2 ⋅ ωE<br />

⋅ s + ωE<br />

)<br />

s : =<br />

⎜<br />

2<br />

2<br />

( s + ω ) ⋅ ( s + ω ⋅ s + ω )<br />

⎝<br />

E ⋅<br />

E<br />

⎛<br />

2 3<br />

⎜ s ⋅<br />

( ) ( 2 ⋅ ω ⋅ s + ωE<br />

)<br />

s : =<br />

⎜<br />

2<br />

2<br />

( s + ω ) ⋅ ( s + ω ⋅ s + ω )<br />

( s )<br />

: =<br />

⎝<br />

⎛<br />

⎜<br />

⎜<br />

⎝<br />

E<br />

21-7<br />

s<br />

E<br />

E<br />

E<br />

E<br />

⎞<br />

⎟<br />

⎟<br />

⎠<br />

E ⋅<br />

2<br />

2<br />

( s + ω ) ⋅ ( s + ω ⋅ s + ω )<br />

E<br />

2<br />

⋅ ω<br />

3<br />

E<br />

E<br />

E<br />

X ~<br />

Equation 21.3-18<br />

⎞<br />

⎟<br />

⎟<br />

⎠<br />

X ~<br />

Equation 21.3-19<br />

⎞<br />

⎟<br />

⎟<br />

⎠<br />

⋅<br />

X ~<br />

Equation 21.3-20<br />

When expressing filter gains in terms of the Butterworth frequency (ωE),<br />

the filter poles are identical and constrained to lie on the unit circle with a<br />

damping of 0.5. Its relationship with the KF and equivalent α−β−γ gains,<br />

⎛<br />

⎜<br />

1 − exp<br />

⎝<br />

K<br />

: =<br />

⎛<br />

⎜<br />

⎝<br />

β<br />

∆t<br />

γ<br />

∆t<br />

α , , 2<br />

( α , β , γ )<br />

⎞<br />

⎟<br />

⎠<br />

Equation 21.3-21<br />

β<br />

4 ⋅ α<br />

( ) ( ) ⎟ − 2 ⋅ ω ⋅ ∆t<br />

, 2 ⋅ 2 − α − 4 ⋅ 1 − α ,<br />

E<br />

Equation 21.3-22<br />

The relationship between the tracking index and butterworth frequency<br />

(ωE),<br />

E<br />

: =<br />

21.4 First Order Correlated Noise Filter<br />

ω<br />

3<br />

σS<br />

σ ⋅ ∆t<br />

M<br />

: =<br />

2<br />

⎞<br />

⎠<br />

Equation 21.3-23<br />

Arcasory [A.5] extended their work to include 1 st order Gauss-Markov<br />

dynamics driven by piecewise continuous jerk. Using the same PI as in<br />

§21.2,

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