55 lines
1.2 KiB
Go
55 lines
1.2 KiB
Go
package controllers
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import (
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"math"
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"git.joco.dk/sng/fermentord/internal/metrics"
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)
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type PIDController struct {
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kp float64
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ki float64
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kd float64
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lastError float64
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lastOutput float64
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integration float64
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lbound float64
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ubound float64
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}
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func NewPIDController(p, i, d float64) *PIDController {
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return &PIDController{
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kp: p, // 2.0
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ki: i, // 0.0001
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kd: d, // 2.0
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lbound: -15.0,
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ubound: 15.0,
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}
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}
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func (p *PIDController) Compute(input float64, setpoint float64) float64 {
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error := setpoint - input
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if p.lastError == 0 {
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p.lastError = error
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}
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pv := p.kp * error
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dv := -(p.kd * (error - p.lastError))
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p.lastError = error
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if p.lastOutput > p.lbound && p.lastOutput < p.ubound {
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p.integration += error
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}
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iv := p.integration * p.ki
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p.lastOutput = math.Max(math.Min(pv+iv+dv, p.ubound), p.lbound)
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metrics.PID.WithLabelValues("pv", "main").Set(pv)
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metrics.PID.WithLabelValues("dv", "main").Set(dv)
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metrics.PID.WithLabelValues("iv", "main").Set(iv)
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metrics.PID.WithLabelValues("offset", "main").Set(p.lastOutput)
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metrics.PID.WithLabelValues("setpoint", "main").Set(setpoint)
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return p.lastOutput
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}
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