Motor Control University

Embedded code implementation

This chapter details the important steps for the embedded real-time implementation of a multi-rate control law. The embedded code is obtained using MPLAB Device Blocks for Simulink. It enables Embedded Coder for automated build and execution of real-time executable for any board equipped with a dsPIC :registered:, PIC32 :registered: or SAM from a Simulink model. Any model can thus be embedded. To compile the generated code and program the board from the Simulink interface with a single “Build” push button on top right of the Simulink interface :

The reasons why MPLAB device blocks for Simulink tool was chosen are:

targets chips rather than demo boards, and is therefore more flexible and usable on home-made prototypes,
implements real-time rate-monotonic scheduling, which facilitates the use of models with multiple sampling periods (other solutions require timers to be configured, and don’t support multitasking),
the entire programming compilation chain is carried out directly from matlab, without having to open an IDE, compiler etc…
has tools for measuring computation time,
peripheral blocks are not blocking (e.g., the ADC just retrieves the result of the previous conversion before launching the next one, which is done in the background),
has an ADC synchronization system (either by counter, or on the PWM). The time base is synchronized to the ADC measurement,
has a light, robust data visualization tool (picgui).

Finally, embedded codes need to respect some constraints described in this chapter, divided into 3 pages:

Real-time implementation

Data Visualization

Data types

References

(Delpoux2021) Delpoux, R., Kerhuel, L., & Léchappé, V. (2021). On Chip Rapid Control Prototyping for DC Motor. J3eA, Journal Sur l’enseignement Des Sciences et Technologies de l’information et Des Systèmes.