MATLAB: Do I receive an error while running the example provided in the section “Rotating the body with the Rotation matrix” of the documentation for SimMechanics 2.2 (R14)

Question

I set up the test body according to the instructions given in the documentation at the following page:

web([docroot,'/toolbox/physmod/mech/mech_review9.html#16600'])

I follow the instructions to set up an inertia tensor given in the "Rotating the Body Relative to Its Center of Gravity" section at the following page:

web([docroot,'/toolbox/physmod/mech/mech_review11.html#16537'])

Upon updating the Simulink diagram, I receive the following error dialog:

 Error evaluating function mech_hgdraw: Error using ==> mech_hgdraw>CreateObjects
 Error: untitled/Body: Body inertia matrix is not symmetric..

The following error message is also displayed at the MATLAB command prompt:

 Error: untitled/Body: Body inertia matrix is not symmetric.

I expect the updated diagram to rotate the body.

Answer 1

This change has been incorporated into the documentation in Release 14 Service Pack 3 (R14SP3). For previous releases, read below for any additional information:

We have verified that this is a bug in the documentation example for SimMechanics 2.2 (R14) as a result of round-off errors. As a work-around, please type the following at the MATLAB command prompt before updating the Simulink diagram:

Irot = (Irot + Irot')/2;