TD uses constructs that are invalid when the block specifies or inherits a continuous sample time. Invalid constructs include the use of persistent or global variables...

Dear all,

I am studying dynamic positioning based an Active Disturbance Rejection Control (ADRC). However, when I run the mdl, there is an error in the Tracking Differentiator (TD) as follows:

"TD uses constructs that are invalid when the block specifies or inherits a continuous sample time. Invalid constructs include the use of persistent or global variables, calls to exported functions or using coder.extrinsic."

I want to know why this error take place and how to solve it?

Thank you very much.

*TD is the component of ADRC and the structure of TD is as follows.

m

[Walter Roberson]

Did you try switching the entire model to discrete time ?