├── .gitattributes ├── .github ├── CODE_OF_CONDUCT.md ├── CONTRIBUTING.md └── workflows │ └── ci.yaml ├── .gitignore ├── Cargo.toml ├── LICENSE-APACHE ├── LICENSE-MIT ├── README.md ├── src └── lib.rs └── tests └── test.rs /.gitattributes: -------------------------------------------------------------------------------- 1 | # Auto detect text files and perform LF normalization 2 | * text=auto 3 | -------------------------------------------------------------------------------- /.github/CODE_OF_CONDUCT.md: -------------------------------------------------------------------------------- 1 | # Contributor Covenant Code of Conduct 2 | 3 | ## Our Pledge 4 | 5 | In the interest of fostering an open and welcoming environment, we as 6 | contributors and maintainers pledge to making participation in our project and 7 | our community a harassment-free experience for everyone, regardless of age, body 8 | size, disability, ethnicity, gender identity and expression, level of 9 | experience, 10 | education, socio-economic status, nationality, personal appearance, race, 11 | religion, or sexual identity and orientation. 12 | 13 | ## Our Standards 14 | 15 | Examples of behavior that contributes to creating a positive environment 16 | include: 17 | 18 | - Using welcoming and inclusive language 19 | - Being respectful of differing viewpoints and experiences 20 | - Gracefully accepting constructive criticism 21 | - Focusing on what is best for the community 22 | - Showing empathy towards other community members 23 | 24 | Examples of unacceptable behavior by participants include: 25 | 26 | - The use of sexualized language or imagery and unwelcome sexual attention or 27 | advances 28 | - Trolling, insulting/derogatory comments, and personal or political attacks 29 | - Public or private harassment 30 | - Publishing others' private information, such as a physical or electronic 31 | address, without explicit permission 32 | - Other conduct which could reasonably be considered inappropriate in a 33 | professional setting 34 | 35 | 36 | ## Our Responsibilities 37 | 38 | Project maintainers are responsible for clarifying the standards of acceptable 39 | behavior and are expected to take appropriate and fair corrective action in 40 | response to any instances of unacceptable behavior. 41 | 42 | Project maintainers have the right and responsibility to remove, edit, or 43 | reject comments, commits, code, wiki edits, issues, and other contributions 44 | that are not aligned to this Code of Conduct, or to ban temporarily or 45 | permanently any contributor for other behaviors that they deem inappropriate, 46 | threatening, offensive, or harmful. 47 | 48 | ## Scope 49 | 50 | This Code of Conduct applies both within project spaces and in public spaces 51 | when an individual is representing the project or its community. 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No contribution is too small and all 7 | contributions are valued. 8 | 9 | This guide explains the process for contributing to the project's GitHub 10 | Repository. 11 | 12 | - [Code of Conduct](#code-of-conduct) 13 | - [Bad Actors](#bad-actors) 14 | 15 | ## Code of Conduct 16 | The project has a [Code of Conduct](./CODE_OF_CONDUCT.md) that *all* 17 | contributors are expected to follow. This code describes the *minimum* behavior 18 | expectations for all contributors. 19 | 20 | As a contributor, how you choose to act and interact towards your 21 | fellow contributors, as well as to the community, will reflect back not only 22 | on yourself but on the project as a whole. 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Giving other 52 | contributors the benefit of the doubt and having a sincere willingness to admit 53 | that you *might* be wrong is critical for any successful open collaboration. 54 | 55 | Don't be a bad actor. 56 | -------------------------------------------------------------------------------- /.github/workflows/ci.yaml: -------------------------------------------------------------------------------- 1 | name: CI 2 | 3 | on: 4 | pull_request: 5 | push: 6 | branches: 7 | - staging 8 | - trying 9 | 10 | env: 11 | RUSTFLAGS: -Dwarnings 12 | 13 | jobs: 14 | build_and_test: 15 | name: Build and test 16 | runs-on: ${{ matrix.os }} 17 | strategy: 18 | matrix: 19 | os: [ubuntu-latest, windows-latest, macOS-latest] 20 | rust: [stable] 21 | 22 | steps: 23 | - uses: actions/checkout@master 24 | 25 | - name: Install ${{ matrix.rust }} 26 | uses: actions-rs/toolchain@v1 27 | with: 28 | toolchain: ${{ matrix.rust }} 29 | override: true 30 | 31 | - name: check 32 | uses: actions-rs/cargo@v1 33 | with: 34 | command: check 35 | args: --all --bins --examples 36 | 37 | - name: check unstable 38 | uses: actions-rs/cargo@v1 39 | with: 40 | command: check 41 | args: --all --benches --bins --examples --tests 42 | 43 | - name: tests 44 | uses: actions-rs/cargo@v1 45 | with: 46 | command: test 47 | args: --all 48 | 49 | check_fmt_and_docs: 50 | name: Checking fmt and docs 51 | runs-on: ubuntu-latest 52 | steps: 53 | - uses: actions/checkout@master 54 | - uses: actions-rs/toolchain@v1 55 | with: 56 | toolchain: nightly 57 | components: rustfmt, clippy 58 | override: true 59 | 60 | - name: fmt 61 | run: cargo fmt --all -- --check 62 | 63 | - name: Docs 64 | run: cargo doc 65 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | target/ 2 | tmp/ 3 | Cargo.lock 4 | .DS_Store 5 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "pid-lite" 3 | version = "1.2.0" 4 | license = "MIT OR Apache-2.0" 5 | repository = "https://github.com/yoshuawuyts/pid-lite" 6 | documentation = "https://docs.rs/pid-lite" 7 | description = "A small PID controller library" 8 | readme = "README.md" 9 | edition = "2018" 10 | keywords = ["pid", "loop", "controller", "control_systems"] 11 | categories = ["algorithms", "date-and-time", "mathematics", "science::robotics", "no-std"] 12 | authors = [ 13 | "Yoshua Wuyts " 14 | ] 15 | 16 | [features] 17 | default = ["std"] 18 | std = [] 19 | 20 | [dependencies] 21 | defmt = { version = "0.2", optional = true } 22 | 23 | [dev-dependencies] 24 | -------------------------------------------------------------------------------- /LICENSE-APACHE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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pid-lite

2 |
3 | 4 | A small PID controller library 5 | 6 |
7 | 8 |
9 | 10 |
11 | 12 | 13 | Crates.io version 15 | 16 | 17 | 18 | Download 20 | 21 | 22 | 23 | docs.rs docs 25 | 26 |
27 | 28 |
29 |

30 | 31 | API Docs 32 | 33 | | 34 | 35 | Releases 36 | 37 | | 38 | 39 | Contributing 40 | 41 |

42 |
43 | 44 | ## Installation 45 | ```sh 46 | $ cargo add pid-lite 47 | ``` 48 | 49 | ## Example 50 | 51 | ```rust 52 | use pid_lite::Controller; 53 | use std::thread; 54 | use std::time::Duration; 55 | 56 | let target = 80.0; 57 | let mut controller = Controller::new(target, 0.25, 0.01, 0.01); 58 | 59 | loop { 60 | let correction = controller.update(measure()); 61 | apply_correction(correction); 62 | thread::sleep(Duration::from_secs(1)); 63 | } 64 | ``` 65 | 66 | ## Safety 67 | This crate uses ``#![deny(unsafe_code)]`` to ensure everything is implemented in 68 | 100% Safe Rust. 69 | 70 | ## Contributing 71 | Want to join us? Check out our ["Contributing" guide][contributing] and take a 72 | look at some of these issues: 73 | 74 | - [Issues labeled "good first issue"][good-first-issue] 75 | - [Issues labeled "help wanted"][help-wanted] 76 | 77 | [contributing]: https://github.com/yoshuawuyts/pid-lite/blob/master.github/CONTRIBUTING.md 78 | [good-first-issue]: https://github.com/yoshuawuyts/pid-lite/labels/good%20first%20issue 79 | [help-wanted]: https://github.com/yoshuawuyts/pid-lite/labels/help%20wanted 80 | 81 | ## License 82 | 83 | 84 | Licensed under either of Apache License, Version 85 | 2.0 or MIT license at your option. 86 | 87 | 88 |
89 | 90 | 91 | Unless you explicitly state otherwise, any contribution intentionally submitted 92 | for inclusion in this crate by you, as defined in the Apache-2.0 license, shall 93 | be dual licensed as above, without any additional terms or conditions. 94 | 95 | -------------------------------------------------------------------------------- /src/lib.rs: -------------------------------------------------------------------------------- 1 | //! A small PID controller library. 2 | //! 3 | //! This crate implements the classic independent PID formulation. 4 | //! 5 | //! # Introduction 6 | //! 7 | //! PID controllers are an integral part of control systems, and provide a way to 8 | //! perform error correction. It's used to control things like throughput or 9 | //! resource allocation: as the resource approaches capacity, the returned 10 | //! correction decreases. And because it is aware of a time factor, it can deal 11 | //! with rapid changes as well. 12 | //! 13 | //! # Loop Tuning 14 | //! 15 | //! However PID controllers are not a silver bullet: they are a tool in a wider 16 | //! toolbox. To maximally benefit from them they need to be tuned to the 17 | //! workload. This is done through three parameters: `proportional_gain`, 18 | //! `integral_gain` and `derivative_gain`. Automated algorithms exist to tune 19 | //! these parameters based on sample workloads, but those are out of scope for 20 | //! this crate. 21 | //! 22 | //! [Read more on loop tuning](https://en.wikipedia.org/wiki/PID_controller#Loop_tuning). 23 | //! 24 | //! # No-std support 25 | //! 26 | //! `#[no_std]` support can be enabled by disabling the default crate-level 27 | //! features. This disables the `Controller::update` method which automatically 28 | //! calculates the time elapsed. Instead use the `Controller::update_elapsed` 29 | //! method which takes an externally calculated `Duration`. 30 | //! 31 | //! # Examples 32 | //! 33 | //! ```no_run 34 | //! use pid_lite::Controller; 35 | //! use std::thread; 36 | //! use std::time::Duration; 37 | //! 38 | //! let target = 80.0; 39 | //! let mut controller = Controller::new(target, 0.25, 0.01, 0.01); 40 | //! 41 | //! loop { 42 | //! let correction = controller.update(measure()); 43 | //! apply_correction(correction); 44 | //! thread::sleep(Duration::from_secs(1)); 45 | //! } 46 | //! # fn measure() -> f64 { todo!() } 47 | //! # fn apply_correction(_: f64) { todo!() } 48 | //! ``` 49 | 50 | #![cfg_attr(not(feature = "std"), no_std)] 51 | #![forbid(unsafe_code)] 52 | #![deny(missing_debug_implementations, nonstandard_style)] 53 | #![warn(missing_docs, future_incompatible, unreachable_pub, rust_2018_idioms)] 54 | 55 | use core::time::Duration; 56 | #[cfg(feature = "std")] 57 | use std::time::Instant; 58 | 59 | /// PID controller 60 | /// 61 | /// The `target` param sets the value we want to reach. The 62 | /// `proportional_gain`, `integral_gain` and `derivative_gain` parameters are all 63 | /// tuning parameters. 64 | /// 65 | /// # Examples 66 | /// 67 | /// ```no_run 68 | /// use pid_lite::Controller; 69 | /// use std::thread; 70 | /// use std::time::Duration; 71 | /// 72 | /// let target = 80.0; 73 | /// let mut controller = Controller::new(target, 0.5, 0.1, 0.2); 74 | /// 75 | /// loop { 76 | /// let correction = controller.update(measure()); 77 | /// apply_correction(correction); 78 | /// thread::sleep(Duration::from_secs(1)); 79 | /// } 80 | /// # fn measure() -> f64 { todo!() } 81 | /// # fn apply_correction(_: f64) { todo!() } 82 | /// ``` 83 | 84 | #[derive(Debug)] 85 | #[cfg_attr(feature = "defmt", derive(defmt::Format))] 86 | pub struct Controller { 87 | target: f64, 88 | 89 | proportional_gain: f64, 90 | integral_gain: f64, 91 | derivative_gain: f64, 92 | 93 | error_sum: f64, 94 | last_error: f64, 95 | #[cfg(feature = "std")] 96 | last_instant: Option, 97 | } 98 | 99 | impl Controller { 100 | /// Create a new instance of `Controller`. 101 | /// 102 | /// # Examples 103 | /// 104 | /// ``` 105 | /// # #![allow(unused_assignments)] 106 | /// use pid_lite::Controller; 107 | /// 108 | /// let target = 80.0; 109 | /// let mut controller = Controller::new(target, 0.20, 0.02, 0.04); 110 | /// ``` 111 | pub const fn new( 112 | target: f64, 113 | proportional_gain: f64, 114 | integral_gain: f64, 115 | derivative_gain: f64, 116 | ) -> Self { 117 | Self { 118 | target, 119 | proportional_gain, 120 | integral_gain, 121 | derivative_gain, 122 | error_sum: 0.0, 123 | last_error: 0.0, 124 | #[cfg(feature = "std")] 125 | last_instant: None, 126 | } 127 | } 128 | 129 | /// Get the target. 130 | /// 131 | /// # Examples 132 | /// 133 | /// ``` 134 | /// # #![allow(unused_assignments)] 135 | /// use pid_lite::Controller; 136 | /// 137 | /// let target = 80.0; 138 | /// let mut controller = Controller::new(target, 0.20, 0.02, 0.04); 139 | /// assert_eq!(controller.target(), 80.0); 140 | /// ``` 141 | pub const fn target(&self) -> f64 { 142 | self.target 143 | } 144 | 145 | /// Set the target. 146 | /// 147 | /// # Examples 148 | /// 149 | /// ``` 150 | /// # #![allow(unused_assignments)] 151 | /// use pid_lite::Controller; 152 | /// 153 | /// let target = 80.0; 154 | /// let mut controller = Controller::new(target, 0.20, 0.02, 0.04); 155 | /// controller.set_target(60.0); 156 | /// assert_eq!(controller.target(), 60.0); 157 | /// ``` 158 | pub fn set_target(&mut self, target: f64) { 159 | self.target = target; 160 | } 161 | 162 | /// Set the proportional gain 163 | pub fn set_proportional_gain(&mut self, proportional_gain: f64) { 164 | self.proportional_gain = proportional_gain; 165 | } 166 | 167 | /// Set the integral gain 168 | pub fn set_integral_gain(&mut self, integral_gain: f64) { 169 | self.integral_gain = integral_gain; 170 | } 171 | 172 | /// Set the derivative gain 173 | pub fn set_derivative_gain(&mut self, derivative_gain: f64) { 174 | self.derivative_gain = derivative_gain; 175 | } 176 | 177 | /// Push an entry into the controller. 178 | /// 179 | /// # Examples 180 | /// 181 | /// ``` 182 | /// # #![allow(unused_assignments)] 183 | /// use pid_lite::Controller; 184 | /// 185 | /// let target = 80.0; 186 | /// let mut controller = Controller::new(target, 0.0, 0.0, 0.0); 187 | /// assert_eq!(controller.update(60.0), 0.0); 188 | /// ``` 189 | /// 190 | /// # Panics 191 | /// 192 | /// This function may panic if the `time_delta` in millis no longer fits in 193 | /// an `f64`. This limit can be encountered when the PID controller is updated on the scale of 194 | /// hours, rather than on the scale of minutes to milliseconds. 195 | #[cfg(feature = "std")] 196 | #[must_use = "A PID controller does nothing if the correction is not applied"] 197 | pub fn update(&mut self, current_value: f64) -> f64 { 198 | let now = Instant::now(); 199 | let elapsed = match self.last_instant { 200 | Some(last_time) => now.duration_since(last_time), 201 | None => Duration::from_millis(1), 202 | }; 203 | self.last_instant = Some(now); 204 | self.update_elapsed(current_value, elapsed) 205 | } 206 | 207 | /// Push an entry into the controller with a time delta since the last update. 208 | /// 209 | /// The `time_delta` value will be rounded down to the closest millisecond 210 | /// with a minimum of 1 millisecond. 211 | /// 212 | /// # Examples 213 | /// 214 | /// ``` 215 | /// # #![allow(unused_assignments)] 216 | /// use pid_lite::Controller; 217 | /// use std::time::Duration; 218 | /// 219 | /// let target = 80.0; 220 | /// let mut controller = Controller::new(target, 0.5, 0.1, 0.2); 221 | /// let dur = Duration::from_millis(2); 222 | /// assert_eq!(controller.update_elapsed(60.0, dur), 16.0); 223 | /// ``` 224 | /// 225 | /// # Panics 226 | /// 227 | /// This function may panic if the `time_delta` in millis no longer fits in 228 | /// an `f64`. This limit can be encountered when the PID controller is updated on the scale of 229 | /// hours, rather than on the scale of minutes to milliseconds. 230 | #[must_use = "A PID controller does nothing if the correction is not applied"] 231 | pub fn update_elapsed(&mut self, current_value: f64, elapsed: Duration) -> f64 { 232 | let elapsed = (elapsed.as_millis() as f64).max(1.0); 233 | 234 | let error = self.target - current_value; 235 | let error_delta = (error - self.last_error) / elapsed; 236 | self.error_sum += error * elapsed; 237 | self.last_error = error; 238 | 239 | let p = self.proportional_gain * error; 240 | let i = self.integral_gain * self.error_sum; 241 | let d = self.derivative_gain * error_delta; 242 | 243 | p + i + d 244 | } 245 | 246 | /// Reset the internal state. 247 | /// 248 | /// # Examples 249 | /// 250 | /// ``` 251 | /// # #![allow(unused_assignments)] 252 | /// use pid_lite::Controller; 253 | /// use std::time::Duration; 254 | /// 255 | /// let target = 80.0; 256 | /// let mut controller = Controller::new(target, 0.0, 0.0, 0.0); 257 | /// let dur = Duration::from_secs(2); 258 | /// let correction = controller.update_elapsed(60.0, dur); 259 | /// 260 | /// controller.reset(); 261 | /// ``` 262 | pub fn reset(&mut self) { 263 | self.reset_inner(); 264 | } 265 | 266 | #[cfg(feature = "std")] 267 | fn reset_inner(&mut self) { 268 | self.error_sum = 0.0; 269 | self.last_error = 0.0; 270 | self.last_instant = None; 271 | } 272 | 273 | #[cfg(not(feature = "std"))] 274 | pub fn reset_inner(&mut self) { 275 | self.error_sum = 0.0; 276 | self.last_error = 0.0; 277 | } 278 | } 279 | 280 | #[cfg(test)] 281 | mod test { 282 | use super::*; 283 | 284 | #[test] 285 | fn base_correction() { 286 | let target = 80.0; 287 | let mut controller = Controller::new(target, 0.5, 0.1, 0.2); 288 | let dur = Duration::from_millis(4); 289 | assert_eq!(controller.update_elapsed(60.0, dur), 19.0); 290 | } 291 | 292 | #[test] 293 | #[cfg(feature = "std")] 294 | fn no_correction() { 295 | let target = 80.0; 296 | let mut controller = Controller::new(target, 0.0, 0.0, 0.0); 297 | assert_eq!(controller.update(60.0), 0.0); 298 | } 299 | 300 | #[test] 301 | #[cfg(feature = "std")] 302 | fn updating_values() { 303 | let target = 80.0; 304 | let mut controller = Controller::new(target, 0.5, 0.1, 0.2); 305 | let dur = Duration::from_millis(4); 306 | assert_eq!(controller.update_elapsed(60.0, dur), 19.0); 307 | controller.set_proportional_gain(0.8); 308 | controller.set_derivative_gain(0.5); 309 | assert_eq!(controller.update_elapsed(60.0, dur), 32.0); 310 | } 311 | } 312 | -------------------------------------------------------------------------------- /tests/test.rs: -------------------------------------------------------------------------------- 1 | 2 | --------------------------------------------------------------------------------