Problem while simulating control surfaces of an aircraft in simulink (Code Attached)

I am trying to simulate the control surface (suppose an elevator using the following blockest. I have the elevator block providing me with Cl Cd and Cm ( lift , drag and pitching coeffiecients) which will be multiplied with 0.5 * p * v* v *S to give the forces. As lift is along negative z and drag along negative x multiplied it with -1. But whenever I am running the simulation its showing the error.

• Derivative of state '1' in block 'controlsurface_trial2/3DOF (Body Axes)/q' at time 0.0 is not finite. The simulation will be stopped. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances) as shown in the figure below:

The code is also attached . For your help ...can you pleas ehelp me out ....stuck in middle of some project for a very long time. Thanks in advance !

Answer 1

[Mohith Kulkarni]

If there is a division by 0 or may be trigonometric infinity solutions. Here 'NaN' is the breakpoint.

To solve these type of errors, you can go try the following steps:

Use the Simulink debugger (in a model window, Simulation > debug > debug model) to identify where is the breakpoint (Inf or NaN) originates. ( Details are here: http://www.mathworks.com/help/simulink/ug/starting-the-simulink-debugger.html )

OR

Use the unit delay block / memory block.

OR

Try reducing fixed step size.

You can refer to the following link for answer by the MathWorks Support Team

Why am I receiving error messages about singularities in my Simulink model? - MATLAB Answers - MATLAB Central (mathworks.com)