use serde::{Serialize, Deserialize}; #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)] pub struct Parameters { pub kp: f32, pub ki: f32, pub kd: f32, pub output_min: f32, pub output_max: f32, pub integral_min: f32, pub integral_max: f32 } impl Default for Parameters { fn default() -> Self { Parameters { kp: 1.5, ki: 0.1, kd: 150.0, output_min: 0.0, output_max: 2.0, integral_min: -10.0, integral_max: 10.0, } } } #[derive(Clone)] pub struct Controller { pub parameters: Parameters, pub target: f64, integral: f64, last_input: Option, pub last_output: Option, } impl Controller { pub const fn new(parameters: Parameters) -> Controller { Controller { parameters: parameters, target: 0.0, last_input: None, integral: 0.0, last_output: None, } } pub fn update(&mut self, input: f64) -> f64 { // error let error = self.target - input; // partial let p = f64::from(self.parameters.kp) * error; // integral self.integral += f64::from(self.parameters.ki) * error; if self.integral < self.parameters.integral_min.into() { self.integral = self.parameters.integral_min.into(); } if self.integral > self.parameters.integral_max.into() { self.integral = self.parameters.integral_max.into(); } let i = self.integral; // derivative let d = match self.last_input { None => 0.0, Some(last_input) => f64::from(self.parameters.kd) * (last_input - input), }; self.last_input = Some(input); // output let mut output = p + i + d; if output < self.parameters.output_min.into() { output = self.parameters.output_min.into(); } if output > self.parameters.output_max.into() { output = self.parameters.output_max.into(); } self.last_output = Some(output); output } pub fn reset(&mut self) { self.integral = 0.0; self.last_input = None; } pub fn summary(&self, channel: usize) -> Summary { Summary { channel, parameters: self.parameters.clone(), target: self.target, integral: self.integral, } } } type JsonBuffer = heapless::Vec; #[derive(Clone, Serialize, Deserialize)] pub struct Summary { channel: usize, parameters: Parameters, target: f64, integral: f64, } impl Summary { pub fn to_json(&self) -> Result { serde_json_core::to_vec(self) } } #[cfg(test)] mod test { use super::*; const PARAMETERS: Parameters = Parameters { kp: 0.055, ki: 0.005, kd: 0.04, output_min: -10.0, output_max: 10.0, integral_min: -100.0, integral_max: 100.0, }; #[test] fn test_controller() { const DEFAULT: f64 = 0.0; const TARGET: f64 = 1234.56; const ERROR: f64 = 0.01; const DELAY: usize = 10; let mut pid = Controller::new(PARAMETERS.clone()); pid.target = TARGET; let mut values = [DEFAULT; DELAY]; let mut t = 0; let mut total_t = 0; let target = (TARGET - ERROR)..=(TARGET + ERROR); while !values.iter().all(|value| target.contains(value)) { let next_t = (t + 1) % DELAY; // Feed the oldest temperature let output = pid.update(values[next_t]); // Overwrite oldest with previous temperature + output values[next_t] = values[t] + output; t = next_t; total_t += 1; } } #[test] fn summary_to_json() { let mut pid = Controller::new(PARAMETERS.clone()); pid.target = 30.0 / 1.1; let buf = pid.summary(0).to_json().unwrap(); assert_eq!(buf[0], b'{'); assert_eq!(buf[buf.len() - 1], b'}'); } }