03. Incorporating Forces
Nd787 C5 L4 A03 L Incorporating Forces V2
Non-linear Equations of Motion
\begin{aligned}
\dot{x}_I &=
u (\cos \theta \cos \psi) + v (\sin \phi \sin \theta \cos \psi - \cos \phi \sin \psi) + w (\cos \phi \sin \theta \cos \psi + \sin \phi \sin \psi) \\
\dot{y}_I &= u (\cos \theta \sin \psi) + v (\sin \phi \sin \theta \cos \psi +
\cos \phi \cos \psi) +
w (\cos \phi \sin \theta \sin \psi - \sin \phi \cos \psi) \\
\dot{z}_I &= - u \sin \theta + v \sin \phi \cos \theta + w \cos \phi \cos \theta \\
\dot{\phi} &= p + r \cos \phi \tan \theta \\
\dot{\theta} &= - r \sin \phi \\
\dot{\psi} &= r \cos \phi \sec \theta \\
\dot{u} &= -g \sin \theta + \frac{\rho V^2 S}{2m}\left [ C_{X_0} + C_{X_\alpha}\alpha
\right ] + T/m +rv \\
\dot{v} &= g \cos \theta \sin \phi + \frac{\rho V^2 S}{2m}\left [ C_{Y_0} + C_{Y_\beta}\beta
+ C_{Y_p}\frac{bp}{2V} + C_{Y_r}\frac{br}{2V} + C_{Y_{\delta_a}\delta_a} + C_{Y_{\delta_r}\delta_r} \right ] +pw - ru \\
\dot{w} &= g \cos \theta \cos \phi + \frac{\rho V^2 S}{2m}\left [ C_{Z_0} + C_{Z_\alpha}\alpha
\right ] -pv \\
\dot{p} &= \left (I_{zz}L + I_{xz}N \right ) / (I_{xx} I_{zz} - I^2_{xz}) \\
\dot{r} &= \left (I_{xz}L + I_{xx}N \right ) / (I_{xx} I_{zz} - I^2_{xz})
\end{aligned}
Note that the L and M in the last two equations correspond to the rolling and yawing moments. The L has nothing to do with lift (even though we use the same letter). These moments are given by:
\begin{aligned}
L&=\frac{1}{2}\rho V^2 S b \left [ C_{l_0} + C_{l_\beta}\beta + C_{l_p}\frac{bp}{2V} + C_{l_r}\frac{br}{2V} + C_{l_{\delta a}} \delta a + C_{l_{\delta r}} \delta r \right ] \\
N&=\frac{1}{2}\rho V^2 S b \left [ C_{r_0} + C_{r_\beta}\beta + C_{r_p}\frac{bp}{2V} + C_{r_r}\frac{br}{2V} + C_{r_{\delta a}} \delta a + C_{r_{\delta r}} \delta r \right ]
\end{aligned}