NaxGCC-FW/src/filter.rs

335 lines
13 KiB
Rust

use defmt::Format;
use libm::{fmaxf, fminf, powf};
use crate::{
config::{ControllerConfig, StickConfig},
helpers::XyValuePair,
};
macro_rules! run_kalman_on_axis {
($self:ident, $axis:ident, $snapback:expr, $vel_weight1:ident, $vel_weight2:ident, $old_pos_filt:ident, $filter_gains:ident, $old_vel_filt:ident, $old_pos_diff:ident, $accel:ident, $vel_smooth:ident, $stick_distance6:ident) => {
if $snapback > 0 {
$self.vel_filt.$axis = $vel_weight1 * $self.vel.$axis
+ (1. - $filter_gains.vel_decay.$axis) * $vel_weight2 * $old_vel_filt.$axis
+ $filter_gains.vel_pos_factor.$axis * $old_pos_diff.$axis;
let pos_weight_vel_acc = 1.
- fminf(
1.,
$vel_smooth.$axis * $vel_smooth.$axis * $filter_gains.vel_thresh
+ $accel.$axis * $accel.$axis * $filter_gains.accel_thresh,
);
let pos_weight1 = fmaxf(pos_weight_vel_acc, $stick_distance6);
let pos_weight2 = 1. - pos_weight1;
$self.pos_filt.$axis = pos_weight1 * $self.pos.$axis
+ pos_weight2
* ($old_pos_filt.$axis
+ (1. - $filter_gains.vel_damp.$axis) * $self.vel_filt.$axis)
} else if $snapback < 0 {
let lpf = $old_pos_filt.$axis * $filter_gains.vel_damp.$axis
+ $self.pos.$axis * (1. - $filter_gains.vel_damp.$axis);
let pos_weight_vel_acc = 1.
- fminf(
1.,
$vel_smooth.$axis * $vel_smooth.$axis * $filter_gains.vel_thresh
+ $accel.$axis * $accel.$axis * $filter_gains.accel_thresh,
);
let pos_weight1 = fmaxf(pos_weight_vel_acc, $stick_distance6);
let pos_weight2 = 1. - pos_weight1;
$self.pos_filt.$axis = pos_weight1 * $self.pos.$axis + pos_weight2 * lpf;
} else {
$self.pos_filt.$axis = $self.pos.$axis;
}
};
}
/// Filter gains for 800Hz, the ones for 1000Hz are provided by `get_norm_gains`
pub const FILTER_GAINS: FilterGains = FilterGains {
max_stick: 100.,
vel_decay: XyValuePair { x: 0.1, y: 0.1 },
vel_pos_factor: XyValuePair { x: 0.01, y: 0.01 },
vel_damp: XyValuePair { x: 0.125, y: 0.125 },
vel_thresh: 1.,
accel_thresh: 3.,
smoothing: XyValuePair { x: 0.0, y: 0.0 },
c_smoothing: XyValuePair { x: 0.0, y: 0.0 },
};
#[derive(Debug, Clone, Default)]
pub struct WaveshapingValues {
pub old_pos: XyValuePair<f32>,
pub old_vel: XyValuePair<f32>,
pub old_out: XyValuePair<f32>,
}
fn calc_waveshaping_mult(setting: u8) -> f32 {
if setting > 0 && setting <= 5 {
1. / (440. - 40. * setting as f32)
} else if setting > 5 && setting <= 15 {
1. / (340. - 20. * setting as f32)
} else {
0.
}
}
fn vel_damp_from_snapback(snapback: i8) -> f32 {
match snapback {
a if a >= 0 => 0.125 * powf(2., (snapback - 4) as f32 / 3.0),
_ => 1. - 0.25 * powf(2., (snapback + 4) as f32 / 3.0),
}
}
#[derive(Clone, Debug, Default, Format)]
pub struct FilterGains {
/// What's the max stick distance from the center
pub max_stick: f32,
/// filtered velocity terms
/// how fast the filtered velocity falls off in the absence of stick movement.
/// Probably don't touch this.
pub vel_decay: XyValuePair<f32>, //0.1 default for 1.2ms timesteps, larger for bigger timesteps
/// how much the current position disagreement impacts the filtered velocity.
/// Probably don't touch this.
pub vel_pos_factor: XyValuePair<f32>, //0.01 default for 1.2ms timesteps, larger for bigger timesteps
/// how much to ignore filtered velocity when computing the new stick position.
/// DO CHANGE THIS
/// Higher gives shorter rise times and slower fall times (more pode, less snapback)
pub vel_damp: XyValuePair<f32>, //0.125 default for 1.2ms timesteps, smaller for bigger timesteps
/// speed and accel thresholds below which we try to follow the stick better
/// These may need tweaking according to how noisy the signal is
/// If it's noisier, we may need to add additional filtering
/// If the timesteps are *really small* then it may need to be increased to get
/// above the noise floor. Or some combination of filtering and playing with
/// the thresholds.
pub vel_thresh: f32, //1 default for 1.2ms timesteps, larger for bigger timesteps
pub accel_thresh: f32, //5 default for 1.2ms timesteps, larger for bigger timesteps
/// This just applies a low-pass filter.
/// The purpose is to provide delay for single-axis ledgedashes.
/// Must be between 0 and 1. Larger = more smoothing and delay.
pub smoothing: XyValuePair<f32>,
/// Same thing but for C-stick
pub c_smoothing: XyValuePair<f32>,
}
impl FilterGains {
/// Returns filter gains for 1000Hz polling rate
pub fn get_normalized_gains(&self, controller_config: &ControllerConfig) -> Self {
let mut gains = self.clone();
gains.vel_damp.x = vel_damp_from_snapback(controller_config.astick_config.x_snapback);
gains.vel_damp.y = vel_damp_from_snapback(controller_config.astick_config.y_snapback);
gains.smoothing.x = controller_config.astick_config.x_smoothing as f32 / 10.;
gains.smoothing.y = controller_config.astick_config.y_smoothing as f32 / 10.;
gains.c_smoothing.x = controller_config.cstick_config.x_smoothing as f32 / 10.;
gains.c_smoothing.y = controller_config.cstick_config.y_smoothing as f32 / 10.;
// The below is assuming the sticks to be polled at 1000Hz
let time_factor = 1.0 / 1.2;
let time_divisor = 1.2 / 1.0;
let vel_thresh = 1.0 / (gains.vel_thresh * time_factor);
let accel_thresh = 1.0 / (gains.accel_thresh * time_factor);
FilterGains {
max_stick: gains.max_stick * gains.max_stick,
vel_decay: XyValuePair {
x: gains.vel_decay.x * time_factor,
y: gains.vel_decay.y * time_factor,
},
vel_pos_factor: XyValuePair {
x: gains.vel_pos_factor.x * time_factor,
y: gains.vel_pos_factor.y * time_factor,
},
vel_damp: XyValuePair {
x: gains.vel_damp.x
* match controller_config.astick_config.x_snapback {
a if a >= 0 => time_factor,
_ => 1.0,
},
y: gains.vel_damp.y
* match controller_config.astick_config.y_snapback {
a if a >= 0 => time_factor,
_ => 1.0,
},
},
vel_thresh,
accel_thresh,
smoothing: XyValuePair {
x: powf(1.0 - gains.smoothing.x, time_divisor),
y: powf(1.0 - gains.smoothing.y, time_divisor),
},
c_smoothing: XyValuePair {
x: powf(1.0 - gains.c_smoothing.x, time_divisor),
y: powf(1.0 - gains.c_smoothing.y, time_divisor),
},
}
}
}
#[derive(Clone, Debug, Format, Default)]
pub struct KalmanState {
pos: XyValuePair<f32>,
vel: XyValuePair<f32>,
vel_filt: XyValuePair<f32>,
pos_filt: XyValuePair<f32>,
}
impl KalmanState {
// runs kalman filter
#[link_section = ".time_critical.run_kalman"]
pub fn run_kalman(
&mut self,
x_z: f32,
y_z: f32,
stick_config: &StickConfig,
filter_gains: &FilterGains,
) -> (f32, f32) {
let old_pos = self.pos;
let old_vel = self.vel;
let old_vel_filt = self.vel_filt;
let old_pos_filt = self.pos_filt;
self.pos.x = x_z;
self.pos.y = y_z;
self.vel.x = x_z - old_pos.x;
self.vel.y = y_z - old_pos.y;
let vel_smooth = XyValuePair {
x: 0.5 * (self.vel.x + old_vel.x),
y: 0.5 * (self.vel.y + old_vel.y),
};
let accel = XyValuePair {
x: self.vel.x - old_vel.x,
y: self.vel.y - old_vel.y,
};
let old_pos_diff = XyValuePair {
x: old_pos.x - old_pos_filt.x,
y: old_pos.y - old_pos_filt.y,
};
let stick_distance2 = fminf(
filter_gains.max_stick,
self.pos.x * self.pos.x + self.pos.y * self.pos.y,
) / filter_gains.max_stick;
let stick_distance6 = stick_distance2 * stick_distance2 * stick_distance2;
let vel_weight1 = stick_distance2;
let vel_weight2 = 1. - vel_weight1;
//modified velocity to feed into our kalman filter.
//We don't actually want an accurate model of the velocity, we want to suppress snapback without adding delay
//term 1: weight current velocity according to r^2
//term 2: the previous filtered velocity, weighted the opposite and also set to decay
//term 3: a corrective factor based on the disagreement between real and filtered position
//the current position weight used for the filtered position is whatever is larger of
// a) 1 minus the sum of the squares of
// 1) the smoothed velocity divided by the velocity threshold
// 2) the acceleration divided by the accel threshold
// b) stick r^6
//When the stick is moving slowly, we want to weight it highly, in order to achieve
// quick control for inputs such as tilts. We lock out using both velocity and
// acceleration in order to rule out snapback.
//When the stick is near the rim, we also want instant response, and we know snapback
// doesn't reach the rim.
//In calculating the filtered stick position, we have the following components
//term 1: current position, weighted according to the above weight
//term 2: a predicted position based on the filtered velocity and previous filtered position,
// with the filtered velocity damped, and the overall term weighted inverse of the previous term
//term 3: the integral error correction term
//But if we xSnapback or ySnapback is zero, we skip the calculation
run_kalman_on_axis!(
self,
x,
stick_config.x_snapback,
vel_weight1,
vel_weight2,
old_pos_filt,
filter_gains,
old_vel_filt,
old_pos_diff,
accel,
vel_smooth,
stick_distance6
);
run_kalman_on_axis!(
self,
y,
stick_config.y_snapback,
vel_weight1,
vel_weight2,
old_pos_filt,
filter_gains,
old_vel_filt,
old_pos_diff,
accel,
vel_smooth,
stick_distance6
);
self.get_xy()
}
pub fn get_xy(&self) -> (f32, f32) {
(self.pos_filt.x, self.pos_filt.y)
}
}
/// This simulates an idealized sort of pode:
///
/// if the stick is moving fast, it responds poorly, while
/// if the stick is moving slowly, it follows closely.
///
/// It's not suitable to be the sole filter, but when put after
/// the smart snapback filter, it should be able to hold the
/// output at the rim longer when released.
///
/// Output is a tuple of the x and y positions.
#[link_section = ".time_critical.run_waveshaping"]
pub fn run_waveshaping(
x_pos: f32,
y_pos: f32,
x_waveshaping: u8,
y_waveshaping: u8,
waveshaping_values: &mut WaveshapingValues,
filter_gains: &FilterGains,
) -> (f32, f32) {
let x_factor = calc_waveshaping_mult(x_waveshaping);
let y_factor = calc_waveshaping_mult(y_waveshaping);
let x_vel = x_pos - waveshaping_values.old_pos.x;
let y_vel = y_pos - waveshaping_values.old_pos.y;
let x_vel_smooth = 0.5 * (x_vel + waveshaping_values.old_vel.x);
let y_vel_smooth = 0.5 * (y_vel + waveshaping_values.old_vel.y);
let old_x_pos_weight = fminf(
1.,
x_vel_smooth * x_vel_smooth * filter_gains.vel_thresh * x_factor,
);
let new_x_pos_weight = 1. - old_x_pos_weight;
let old_y_pos_weight = fminf(
1.,
y_vel_smooth * y_vel_smooth * filter_gains.vel_thresh * y_factor,
);
let new_y_pos_weight = 1. - old_y_pos_weight;
let x_out = x_pos * new_x_pos_weight + waveshaping_values.old_out.x * old_x_pos_weight;
let y_out = y_pos * new_y_pos_weight + waveshaping_values.old_out.y * old_y_pos_weight;
waveshaping_values.old_pos.x = x_pos;
waveshaping_values.old_pos.y = y_pos;
waveshaping_values.old_vel.x = x_vel_smooth;
waveshaping_values.old_vel.y = y_vel_smooth;
waveshaping_values.old_out.x = x_out;
waveshaping_values.old_out.y = y_out;
(x_out, y_out)
}