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

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Chapter 6 / Missile Guidance<br />

_ _<br />

Substituting for angular momentum in the moment balance, and treating the<br />

moments of inertia as quasi-static parameters results in the Euler equations,<br />

B<br />

XX<br />

XB<br />

C, B<br />

XB<br />

m<br />

6-38<br />

B B YB ZB<br />

( I − I ) ⋅ ω ⋅<br />

I ⋅ ω&<br />

: = M +<br />

ω<br />

B<br />

YY<br />

YB<br />

C, B<br />

YB<br />

m<br />

YY<br />

ZZ<br />

C,<br />

B<br />

C,<br />

B<br />

B B XB ZB<br />

( I − I ) ⋅ ω ⋅<br />

I ⋅ ω&<br />

: = M +<br />

ω<br />

B<br />

ZZ<br />

ZB<br />

C, B<br />

ZB<br />

m<br />

ZZ<br />

XX<br />

C,<br />

B<br />

Equation 6.10-17<br />

C,<br />

B<br />

B B XB YB<br />

( I − I ) ⋅ ω ⋅<br />

I ⋅ ω&<br />

: = M +<br />

ω<br />

XX<br />

YY<br />

C,<br />

B<br />

Equation 6.10-18<br />

C,<br />

B<br />

Equation 6.10-19<br />

Earth rotational acceleration has been ignored. The external moments arise<br />

from the gravitational force acting at the centre of mass in a uniform field,<br />

and the aerodynamic moment (MA) referenced to point (m),<br />

B<br />

m<br />

B<br />

A<br />

m<br />

B<br />

m,<br />

c<br />

B G ( T G )<br />

M : = M + m ⋅ P × ⋅<br />

G<br />

m<br />

Equation 6.10-20<br />

Substituting for gravity and expressing the result in the Missile Body frame,<br />

B<br />

m<br />

B<br />

A<br />

m<br />

B<br />

m,<br />

c<br />

B G B B B<br />

( T ⋅ g + ω × ω P )<br />

M : = M + m ⋅ P ×<br />

×<br />

G<br />

m<br />

C,<br />

E<br />

Expanding and ignoring earth rate and tilt dependent terms,<br />

B<br />

YY<br />

YB<br />

A, B<br />

B<br />

XX<br />

XB<br />

A, B<br />

XB<br />

A<br />

C,<br />

E<br />

B B YB ZB<br />

( I − I ) ⋅ ω ⋅<br />

I ⋅ ω&<br />

: = M +<br />

ω<br />

YB<br />

m<br />

YY<br />

ZZ<br />

A,<br />

B<br />

r,<br />

m<br />

Equation 6.10-21<br />

A,<br />

B<br />

Equation 6.10-22<br />

B B XB ZB<br />

XB B ZA<br />

( I − I ) ⋅ ω ⋅ ω + m ⋅ P ⋅ T ( 9 ) g<br />

I ⋅ ω&<br />

: = M +<br />

⋅<br />

B<br />

ZZ<br />

ZB<br />

C, B<br />

ZB<br />

m<br />

ZZ<br />

XX<br />

A,<br />

B<br />

A,<br />

B<br />

m<br />

m,<br />

c<br />

G<br />

m<br />

Equation 6.10-23<br />

B B XB YB<br />

XB B ZG<br />

( I − I ) ⋅ ω ⋅ ω + m ⋅ P ⋅ T ( 6 ) g<br />

I ⋅ ω&<br />

: = M +<br />

⋅<br />

XX<br />

YY<br />

C,<br />

B<br />

C,<br />

B<br />

m<br />

m,<br />

c<br />

G<br />

m<br />

Equation 6.10-24<br />

For more complex models the aerodynamic moment comprises terms due to<br />

missile incidence, damping and control surface deflection expressed in the<br />

Missile Body frame,

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