pid-controller 0.1.0

PID controller library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133

use std::ops::{Add, Div, Mul, Sub};

use num_traits::One;

#[derive(Clone, Copy, Debug)]

/// Proportional controller
pub struct P<T> {
    pub kp: T,
}

impl<T: One> Default for P<T> {
    fn default() -> Self {
        Self { kp: T::one() }
    }
}

impl<T> P<T> {
    // Between 0.7 and 1
    pub fn new(damping_ratio: T, time_constant: T) -> Self
    where
        T: One + Add<Output = T> + Div<Output = T> + Copy,
    {
        let kp = (T::one() / (time_constant * time_constant))
            * (T::one() + (T::one() + T::one()) * damping_ratio);
        Self { kp }
    }

    pub fn control<U>(self, target: U, actual: U) -> T::Output
    where
        T: Mul<U> + Clone,
        U: Sub<Output = U>,
    {
        let error = error(target, actual);
        self.control_with_error(error)
    }

    pub fn control_with_error<U>(&self, error: U) -> T::Output
    where
        T: Mul<U> + Clone,
    {
        self.kp.clone() * error
    }
}

#[derive(Clone, Debug)]
pub struct PD<T> {
    pub p: P<T>,
    pub kd: T,
}

impl<T> PD<T> {
    pub fn new(damping_ratio: T, time_constant: T) -> Self
    where
        T: One + Add<Output = T> + Div<Output = T> + Copy,
    {
        let kd = (T::one() / time_constant)
            * (T::one() + (T::one() + T::one()) * time_constant * time_constant);
        Self {
            p: P::new(damping_ratio, time_constant),
            kd,
        }
    }

    pub fn control<U>(&self, target: U, target_dot: U, actual: U, actual_dot: U) -> U
    where
        T: Mul<U, Output = U> + Sub<Output = T> + Clone,
        U: Add<Output = U> + Sub<Output = U>,
    {
        let p = self.p.clone().control(target, actual);
        self.control_with_p(p, target_dot, actual_dot)
    }

    pub fn control_with_p<U>(&self, p: U, target_dot: U, actual_dot: U) -> U
    where
        T: Mul<U, Output = U> + Clone,
        U: Add<Output = U> + Sub<Output = U>,
    {
        self.kd.clone() * (target_dot - actual_dot) + p
    }
}

pub fn error<T>(target: T, actual: T) -> T
where
    T: Sub<Output = T>,
{
    target - actual
}

#[derive(Clone, Debug)]
pub struct PID {
    pub pd: PD<f32>,
    pub ki: f32,
    pub integrated_error: f32,
}

impl PID {
    pub fn new(damping_ratio: f32, time_constant: f32) -> Self {
        let ki = 1. / time_constant.powi(3);
        Self {
            pd: PD::new(damping_ratio, time_constant),
            ki,
            integrated_error: 0.,
        }
    }

    pub fn control(
        &mut self,
        target: f32,
        target_dot: f32,
        actual: f32,
        actual_dot: f32,
        dt: f32,
    ) -> f32 {
        let error = error(target, actual);
        self.integrated_error += error * dt;

        let p = self.pd.p.control_with_error(error);
        let i = self.integrated_error * self.ki;
        let d = self.pd.control_with_p(p, target_dot, actual_dot);

        p + i + d
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        let result = 2 + 2;
        assert_eq!(result, 4);
    }
}