forked from M-Labs/thermostat
130 lines
3.3 KiB
Rust
130 lines
3.3 KiB
Rust
use serde::{Serialize, Deserialize};
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#[derive(Clone, Serialize, Deserialize)]
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pub struct Parameters {
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pub kp: f32,
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pub ki: f32,
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pub kd: f32,
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pub output_min: f32,
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pub output_max: f32,
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pub integral_min: f32,
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pub integral_max: f32
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}
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impl Default for Parameters {
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fn default() -> Self {
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Parameters {
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kp: 1.5,
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ki: 0.1,
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kd: 150.0,
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output_min: 0.0,
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output_max: 2.0,
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integral_min: -10.0,
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integral_max: 10.0,
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}
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}
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}
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#[derive(Clone)]
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pub struct Controller {
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pub parameters: Parameters,
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pub target: f64,
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integral: f64,
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last_input: Option<f64>,
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pub last_output: Option<f64>,
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}
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impl Controller {
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pub const fn new(parameters: Parameters) -> Controller {
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Controller {
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parameters: parameters,
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target: 0.0,
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last_input: None,
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integral: 0.0,
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last_output: None,
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}
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}
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pub fn update(&mut self, input: f64) -> f64 {
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// error
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let error = self.target - input;
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// partial
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let p = f64::from(self.parameters.kp) * error;
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//integral
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self.integral += error;
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if self.integral < self.parameters.integral_min.into() {
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self.integral = self.parameters.integral_min.into();
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}
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if self.integral > self.parameters.integral_max.into() {
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self.integral = self.parameters.integral_max.into();
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}
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let i = f64::from(self.parameters.ki) * f64::from(self.integral);
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// derivative
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let d = match self.last_input {
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None => 0.0,
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Some(last_input) => f64::from(self.parameters.kd) * (last_input - input)
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};
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self.last_input = Some(input);
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// output
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let mut output = p + i + d;
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if output < self.parameters.output_min.into() {
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output = self.parameters.output_min.into();
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}
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if output > self.parameters.output_max.into() {
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output = self.parameters.output_max.into();
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}
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self.last_output = Some(output);
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output
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}
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#[allow(dead_code)]
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pub fn reset(&mut self) {
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self.integral = 0.0;
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self.last_input = None;
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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const PARAMETERS: Parameters = Parameters {
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kp: 0.055,
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ki: 0.005,
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kd: 0.04,
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output_min: -10.0,
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output_max: 10.0,
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integral_min: -100.0,
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integral_max: 100.0,
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};
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#[test]
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fn test_controller() {
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const DEFAULT: f64 = 0.0;
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const TARGET: f64 = 1234.56;
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const ERROR: f64 = 0.01;
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const DELAY: usize = 10;
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let mut pid = Controller::new(PARAMETERS.clone());
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pid.target = TARGET;
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let mut values = [DEFAULT; DELAY];
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let mut t = 0;
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let mut total_t = 0;
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let target = (TARGET - ERROR)..=(TARGET + ERROR);
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while !values.iter().all(|value| target.contains(value)) {
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let next_t = (t + 1) % DELAY;
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// Feed the oldest temperature
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let output = pid.update(values[next_t]);
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// Overwrite oldest with previous temperature + output
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values[next_t] = values[t] + output;
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t = next_t;
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total_t += 1;
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}
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}
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}
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