4 ms·
For temperature control, you probably want to use a PI controller with Anti-windup. This will compensate for the limits on actuator (heating element) output, an
by dbcooper 12y ago
For temperature control, you probably want to use a PI controller with Anti-windup. This will compensate for the limits on actuator (heating element) output, and prevent large overshoots from "windup" of the Integral element.
http://jagger.berkeley.edu/~pack/me132/Section15.pdf http://jagger.berkeley.edu/~pack/me132/Section15.pdf
- pi-rat 12y agoVery good tip, thanks! I'll consider that for my proper setup, I've had some problems finding proper calibration values for some water containers and heaters because of the lag in the system.
- someengineer 12y agoTo elaborate on why you can typically avoid derivative control for thermodynamic processes: There's no natural resonance in the system caused by energy-storing elements. For instance, if you drop a cold egg into a pot of water at exactly 80 C, it won't overshoot and go up to 85 C before settling to 80 C. Mechanical systems on the other hand often have "spring-like" behavior that causes them to resonate at certain frequencies. If you want to get hardcore with the control design then you could look into fuzzy logic controllers. It's common in high-end appliances: http://en.wikipedia.org/wiki/Fuzzy_control_system http://en.wikipedia.org/wiki/Fuzzy_control_system