Hi,
The idgrey function in MATLAB is a built-in function for system identification of grey-box models. Grey-box models are models that combine known physical knowledge about a system with empirical data. The idgrey function estimates the parameters of a grey-box model based on input-output data.
The specific implementation of idgrey function in MATLAB is not publicly available, but the general idea behind grey-box modeling is to combine a physical model with a statistical model. In the case of idgrey, the physical model is typically expressed as a state-space model with unknown parameters, and the statistical model is used to estimate the unknown parameters based on measured input-output data.
The idgrey function uses optimization algorithms to estimate the unknown parameters of the state-space model. These optimization algorithms iteratively adjust the values of the model parameters to minimize the difference between the model predictions and the measured data. The optimization algorithms used by idgrey depend on the specific estimation method selected by the user.
Thanks
