I am working on a flight simulator for control algorithm testing. The issue I am facing is to come up with a relationship between CL/CD/CM and the angle of attack ($\alpha$) and the control surface deflection angle ($\delta$).
Since I'm developing a control algorithm for a flying wing, it is crucial to know how not only $\alpha$ but also $\delta$ affect the forces and moments on my flight vehicle. And I cannot afford to measure the forces and moments experimentally.
In the Gazebo simulator, the LiftDragPlugin's approach is to assume that the lift curve shifts up and down by $\delta$ times some constant. However, that is not the case, as can be seen from the numerical results from XFLR5 below.
Where “Plane Name $\pm\delta$” describes the curve for any $\delta$.
We can see that the curve shifts in both direction from zero-$\delta$ position. For instance, the stall angle decreases as $\delta$ increases.
My current approach is to construct a three-dimensional lookup table by using the curves at $-\delta$ and $+\delta$ as endpoints and linearly interpolate the two curves along the z-axis. When I need the aerodynamic parameter (CL, CD, or CM) at some $\alpha_0$ and $\delta_0$, I can just locate the point in this three-dimensional space from $\alpha_0$ and $\delta_0$.
Is this a valid way to determine CL/CD/CM as a function of $\alpha$ and $\delta$ numerically? If not, how should I approach this problem?