Draft:Take-back-half controller

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{{AFC comment|1=Only one source, need more —pythoncoder (talk | contribs) 03:37, 9 June 2025 (UTC)}}

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A Take-back-half controller is a feedback loop used to manage processes that are required to maintain a constant variable, frequently temperature or speed. It works based on integrating the difference between the measured variable and its setpoint in which it is desired to be at, while trying to minimize oscillation by decreasing the integral value every time that the sign of the error changes, dividing the integral term by 2 and adding a setpoint value which dynamically changes every time that the sign of the error swaps.

Pseudocode

previous_error := 0

integral := 0

tbh := 0

kH := 0

loop:

error := setpoint - measured_value

integral := integral + error

if not (sgn(error) == sgn(previous_error)):

integral := (integral + tbh) / 2

tbh = integral

previous_error = error

output := kH * integral

In this implementation kH is the singular tuning factor, directly multiplying the value, which is one of the major advantages of the Take-back-half algorithm, where tbh is the setpoint, which is automatically tuned at runtime, despite the algorithm's much simpler usage than other control algorithms such as PID, it has multiple problems that it frequently does better in, such as flywheel speed control.

References

Christopher Samuel Harper (2011) "[https://scholarsjunction.msstate.edu/td/718/ Application of the Take-Back-Half algorithm to voltage source converter current control]" - Mississippi State University