Overview

Controller block diagram

This proportional-integral-derivative (PID) controller, implemented wholly within helm.h, features:

• low pass filtering of the process derivative,
• windup protection,
• automatic reset on actuator saturation,
• anti-kick on setpoint change using "derivative on measurement",
• incremental output for bumpless manual-to-automatic transitions,
• a unified controller gain parameter,
• exposure of all independent physical time scales, and
• the ability to accommodate varying sample rate.

This project and its API documentation are hosted at https://github.com/RhysU/helm and https://rhysu.github.io/helm/, respectively.

References

• Astrom, Karl J. and Richard M. Murray. Feedback systems: an introduction for scientists and engineers. Princeton University Press, April 2008. Available online.
• Wescott, Tim. Applied control theory for embedded systems. Newnes, 2006.