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
134
135
136
137
138
139
140
141
142
143
#![allow(non_upper_case_globals)]
use crate::utils::array_to_isometry;
use std::f64::consts::PI;
pub static kMaxCutoffFrequency: f64 = 1000.0;
pub static kDefaultCutoffFrequency: f64 = 100.0;
pub fn low_pass_filter(sample_time: f64, y: f64, y_last: f64, cutoff_frequency: f64) -> f64 {
assert!(sample_time.is_sign_positive() && sample_time.is_finite());
assert!(cutoff_frequency.is_sign_positive() && cutoff_frequency.is_finite());
assert!(y.is_finite() && y_last.is_finite());
let gain = sample_time / (sample_time + (1.0 / (2.0 * PI * cutoff_frequency)));
gain * y + (1. - gain) * y_last
}
pub fn cartesian_low_pass_filter(
sample_time: f64,
y: &[f64; 16],
y_last: &[f64; 16],
cutoff_frequency: f64,
) -> [f64; 16] {
assert!(sample_time.is_sign_positive() && sample_time.is_finite());
assert!(cutoff_frequency.is_sign_positive() && cutoff_frequency.is_finite());
y.iter()
.zip(y_last.iter())
.for_each(|(i, j)| assert!(i.is_finite() && j.is_finite()));
let mut transform = array_to_isometry(&y);
let transform_last = array_to_isometry(&y_last);
let gain = sample_time / (sample_time + (1.0 / (2.0 * PI * cutoff_frequency)));
transform.translation.vector =
gain * transform.translation.vector + (1. - gain) * transform_last.translation.vector;
transform.rotation = transform_last.rotation.slerp(&transform.rotation, gain);
let mut out = [0.; 16];
for (i, &x) in transform.to_homogeneous().iter().enumerate() {
out[i] = x;
}
out
}
#[cfg(test)]
mod tests {
use crate::robot::low_pass_filter::{cartesian_low_pass_filter, low_pass_filter};
#[test]
fn low_pass_test() {
assert!(f64::abs(low_pass_filter(0.001, 1.0, 1.0, 100.0) - 1.) < 0.000001);
assert!(f64::abs(low_pass_filter(0.001, 1.0, 1.0, 500.0) - 1.) < 0.000001);
assert!(f64::abs(low_pass_filter(0.001, 1.0, 1.0, 1000.0) - 1.) < 0.000001);
assert!(f64::abs(low_pass_filter(0.001, 1.0, 0.0, 100.0) - 0.3859) < 0.0001);
assert!(f64::abs(low_pass_filter(0.001, 1.0, 0.0, 500.0) - 0.7585) < 0.0001);
assert!(f64::abs(low_pass_filter(0.001, 1.0, 0.0, 900.0) - 0.8497) < 0.0001);
}
#[test]
fn low_pass_cartesian_test() {
let sample_time = 0.001;
let cutoff_frequency = 100.;
let y = [
0.9999903734042686,
0.0000000002540163079878255,
-0.00000000012581154368346085,
0.0,
0.0000000002540163079878255,
-0.9999903734042686,
0.00000000004614105974113725,
0.0,
-0.00000000012581275483128821,
-0.000000000046141503958700795,
-1.0,
0.0,
0.30689056659844144,
0.0000000000692086410879149,
0.4868820527992277,
1.0,
];
let y_last = [
0.9999903734042686,
0.0000000002540163079878255,
-0.00000000012581154368346085,
0.0,
0.0000000002540163079878255,
-0.9999903734042686,
0.00000000004614105974113725,
0.0,
-0.00000000012581275483128821,
-0.000000000046141503958700795,
-1.0,
0.0,
0.30689056659844144,
0.0000000000692086410879149,
0.4868820527992277,
1.0,
];
println!(
"{:?}",
cartesian_low_pass_filter(sample_time, &y, &y_last, cutoff_frequency)
);
}
}