UAV Toolbox Guidance Model block has mask callback that modifies model at compile time, which prohibits multi-instance model reference

UAV Toolbox Guidance Model block, doc link: Reduced-order model for UAV - Simulink (mathworks.com), consists mask callbacks that perform tasks such as bus object creation according to UAV type & data type. This poses problem in situations such as the one in the attachment, where ChildMdl.slx containing this block is being refered twice in the ParentMdl.slx, i.e. multi-instance of the child model under the same parent model. Try to run ParentMdl.slx and see the error message:

The model 'ChildMdl' has changed between the time when two instances of this model were compiled. This is not allowed for models referenced in Normal Mode.

I tried to completely dismantle the mask of this block, however, this error message persists. It is potentially due to the inner mask on top of the ComputeDerivative & StateVector2Struct system object. Does anybody know any workaround?

Answer 1

[Jianxin Sun]

Hi Zhang,

Thanks for bringing up this issue. You can try a few workarounds:

1. You can change the model reference block's simulation mode to accelerator mode. Check the doc page for reference.

open_system('ParentMdl.slx');
set_param('ParentMdl/UAV1', 'SimulationMode', 'Accelerator');
set_param('ParentMdl/UAV2', 'SimulationMode', 'Accelerator');

This should let you simulate from parent model.

2. Alternatively, you can use the fixedwing MATLAB API in a MATLAB function block. This should let you compute the derivatives of the equation of motion. You can then use integrator block to get the UAV state.

Thanks,

Jianxin

[Yingao Zhang]

Hi, Jianxin, Thanks for your brilliant idea. I actually translated the block into S-function using embedded coder as workaround. Which is functionally the same as accelerator run. Cheers!