Quick-fix: MATLAB FMU import error

MATLAB 2017b introduced support for the Functional Mock-up Standard by providing FMU-import blocks in Simulink. This open standard enables mixing of simulation models created with different tools, like prototype controllers before coding them. This is an extremely powerful feature that I will write more about in soon. This memo, however, is about an error that occurred to me when importing an FMU in Simulink and how to fix it. 

The error is something like:

The FMU error dialog, shown by MATLAB
Error parsing FMU ‘dq.fmu’. Caused by: – Error in supplied FMU: Dynamic library file (‘dq.dylib’) does not exist in FMU ‘dq.fmu’.

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Implementing a MATLAB digital filter or controllers in C++

Controllers and filters are often a good way to stabilise a system, condition a signal or make a system follow a reference. The usual approach is to model the system or signal in an application like MATLAB and then design a filter or controller. Either by applying design rules, some sort of optimisation algorithm or tuning parameters experimentally. When the design is finished the controller or filter is not ready for use yet. It is still necessary to realise it in practice. This is often done digitally on a micro controller or real-time computer. This article will describe a effective, open and fast approach to realising a filter or controller in C++.

Step responses of Butterworth Low-pass Filters
Step responses of Butterworth Low-pass digital filters with different cut-off frequencies

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Random Midpoint Displacement Fractal (RMDF)

The Random Midpoint Displacement Fractal (RMDF) is a fractal this is often used for generating height-maps, landscapes, rough surfaces and more. Its implementation is simple but the results are interesting, especially when a nice color-map is applied to the matrix and it is shown as a 3D-surface.

Example of a Random Midpoint Displacement Fractal

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Matlab2Tikz: Perfect MATLAB Figures in LaTeX

MATLAB exported TikZ picture with custom stylingPapers and reports can’t do without both but integrating MATLAB figures in LaTeX is not so obvious. Different methods for exporting and including graphics exist but have various downsides like inconsistent scaling, wrong fonts and strange spacing. The best method I have come across so far is using matlab2tikz. It is a MATLAB script that is able to extract all relevant details out of a figure and convert it to PGFPlots (a LaTeX package).

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