feat(filter): implement kalman filter

This commit is contained in:
Naxdy 2024-03-27 21:20:25 +01:00
parent b0e1eb6309
commit eb0ba44b1c
Signed by untrusted user: Naxdy
GPG key ID: CC15075846BCE91B
6 changed files with 232 additions and 80 deletions

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@ -11,7 +11,7 @@ use embassy_rp::{
use packed_struct::{derive::PackedStruct, PackedStruct};
use crate::{
packed_float::{PackedFloat, ToPackedFloatArray},
helpers::{PackedFloat, ToPackedFloatArray},
stick::{NotchStatus, NO_OF_CALIBRATION_POINTS, NO_OF_NOTCHES},
ADDR_OFFSET, FLASH_SIZE,
};

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@ -1,33 +1,68 @@
use defmt::Format;
use libm::{fminf, powf};
use libm::{fmaxf, fminf, powf};
use crate::config::ControllerConfig;
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.,
x_vel_decay: 0.1,
y_vel_decay: 0.1,
x_vel_pos_factor: 0.01,
y_vel_pos_factor: 0.01,
x_vel_damp: 0.125,
y_vel_damp: 0.125,
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.,
x_smoothing: 0.0,
y_smoothing: 0.0,
c_xsmoothing: 0.0,
c_ysmoothing: 0.0,
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_x_pos: f32,
pub old_y_pos: f32,
pub old_x_vel: f32,
pub old_y_vel: f32,
pub old_x_out: f32,
pub old_y_out: f32,
pub old_pos: XyValuePair<f32>,
pub old_vel: XyValuePair<f32>,
pub old_out: XyValuePair<f32>,
}
fn calc_waveshaping_mult(setting: u8) -> f32 {
@ -54,17 +89,14 @@ pub struct FilterGains {
/// filtered velocity terms
/// how fast the filtered velocity falls off in the absence of stick movement.
/// Probably don't touch this.
pub x_vel_decay: f32, //0.1 default for 1.2ms timesteps, larger for bigger timesteps
pub y_vel_decay: f32,
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 x_vel_pos_factor: f32, //0.01 default for 1.2ms timesteps, larger for bigger timesteps
pub y_vel_pos_factor: f32,
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 x_vel_damp: f32, //0.125 default for 1.2ms timesteps, smaller for bigger timesteps
pub y_vel_damp: f32,
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
@ -76,11 +108,9 @@ pub struct FilterGains {
/// 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 x_smoothing: f32,
pub y_smoothing: f32,
pub smoothing: XyValuePair<f32>,
/// Same thing but for C-stick
pub c_xsmoothing: f32,
pub c_ysmoothing: f32,
pub c_smoothing: XyValuePair<f32>,
}
impl FilterGains {
@ -88,14 +118,14 @@ impl FilterGains {
pub fn get_normalized_gains(&self, controller_config: &ControllerConfig) -> Self {
let mut gains = self.clone();
gains.x_vel_damp = vel_damp_from_snapback(controller_config.astick_config.x_snapback);
gains.y_vel_damp = vel_damp_from_snapback(controller_config.astick_config.y_snapback);
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.x_smoothing = controller_config.astick_config.x_smoothing as f32 / 10.;
gains.y_smoothing = controller_config.astick_config.y_smoothing as f32 / 10.;
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_xsmoothing = controller_config.cstick_config.x_smoothing as f32 / 10.;
gains.c_ysmoothing = controller_config.cstick_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;
@ -106,37 +136,149 @@ impl FilterGains {
FilterGains {
max_stick: gains.max_stick * gains.max_stick,
x_vel_decay: gains.x_vel_decay * time_factor,
y_vel_decay: gains.y_vel_decay * time_factor,
x_vel_pos_factor: gains.x_vel_pos_factor * time_factor,
y_vel_pos_factor: gains.y_vel_pos_factor * time_factor,
x_vel_damp: gains.x_vel_damp
* match controller_config.astick_config.x_snapback {
a if a >= 0 => time_factor,
_ => 1.0,
},
y_vel_damp: gains.y_vel_damp
* match controller_config.astick_config.y_snapback {
a if a >= 0 => time_factor,
_ => 1.0,
},
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,
x_smoothing: powf(1.0 - gains.x_smoothing, time_divisor),
y_smoothing: powf(1.0 - gains.y_smoothing, time_divisor),
c_xsmoothing: powf(1.0 - gains.c_xsmoothing, time_divisor),
c_ysmoothing: powf(1.0 - gains.c_ysmoothing, time_divisor),
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),
},
}
}
}
pub fn run_kalman(
x_z: f32,
y_z: f32,
controller_config: &ControllerConfig,
filter_gains: &FilterGains,
) -> (f32, f32) {
todo!()
#[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
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:
@ -160,11 +302,11 @@ pub fn run_waveshaping(
let x_factor = calc_waveshaping_mult(x_waveshaping);
let y_factor = calc_waveshaping_mult(y_waveshaping);
let x_vel = x_pos - waveshaping_values.old_x_pos;
let y_vel = y_pos - waveshaping_values.old_y_pos;
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_x_vel);
let y_vel_smooth = 0.5 * (y_vel + waveshaping_values.old_y_vel);
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.,
@ -177,15 +319,15 @@ pub fn run_waveshaping(
);
let new_y_pos_weight = 1. - old_y_pos_weight;
let x_out = x_pos * new_x_pos_weight + waveshaping_values.old_x_out * old_x_pos_weight;
let y_out = y_pos * new_y_pos_weight + waveshaping_values.old_y_out * 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_x_pos = x_pos;
waveshaping_values.old_y_pos = y_pos;
waveshaping_values.old_x_vel = x_vel_smooth;
waveshaping_values.old_y_vel = y_vel_smooth;
waveshaping_values.old_x_out = x_out;
waveshaping_values.old_y_out = y_out;
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)
}

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@ -46,3 +46,9 @@ impl Deref for PackedFloat {
&self.0
}
}
#[derive(Debug, Clone, Format, Default, Copy)]
pub struct XyValuePair<T> {
pub x: T,
pub y: T,
}

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@ -16,7 +16,7 @@ use libm::{fmaxf, fminf};
use crate::{
config::ControllerConfig,
filter::{run_kalman, run_waveshaping, FilterGains, WaveshapingValues, FILTER_GAINS},
filter::{run_waveshaping, FilterGains, KalmanState, WaveshapingValues, FILTER_GAINS},
gcc_hid::GcReport,
stick::{linearize, notch_remap, StickParams},
FLASH_SIZE,
@ -125,6 +125,7 @@ async fn update_stick_states<
cstick_waveshaping_values: &mut WaveshapingValues,
old_stick_pos: &mut StickPositions,
raw_stick_values: &mut RawStickValues,
kalman_state: &mut KalmanState,
) -> StickState {
let mut adc_count = 0u32;
let mut ax_sum = 0u32;
@ -203,7 +204,8 @@ async fn update_stick_states<
raw_stick_values.cx_linearized = pos_cx;
raw_stick_values.cy_linearized = pos_cy;
let (x_pos_filt, y_pos_filt) = run_kalman(x_z, y_z, controller_config, &filter_gains);
let (x_pos_filt, y_pos_filt) =
kalman_state.run_kalman(x_z, y_z, &controller_config.astick_config, &filter_gains);
let (shaped_x, shaped_y) = run_waveshaping(
x_pos_filt,
@ -215,9 +217,9 @@ async fn update_stick_states<
);
let pos_x: f32 =
filter_gains.x_smoothing * shaped_x + (1.0 - filter_gains.x_smoothing) * old_stick_pos.x;
filter_gains.smoothing.x * shaped_x + (1.0 - filter_gains.smoothing.x) * old_stick_pos.x;
let pos_y =
filter_gains.y_smoothing * shaped_y + (1.0 - filter_gains.y_smoothing) * old_stick_pos.y;
filter_gains.smoothing.y * shaped_y + (1.0 - filter_gains.smoothing.y) * old_stick_pos.y;
old_stick_pos.x = pos_x;
old_stick_pos.y = pos_y;
@ -235,9 +237,9 @@ async fn update_stick_states<
old_stick_pos.cx = shaped_cx;
old_stick_pos.cy = shaped_cy;
let x_weight_1 = filter_gains.c_xsmoothing;
let x_weight_1 = filter_gains.c_smoothing.x;
let x_weight_2 = 1.0 - x_weight_1;
let y_weight_1 = filter_gains.c_ysmoothing;
let y_weight_1 = filter_gains.c_smoothing.y;
let y_weight_2 = 1.0 - y_weight_1;
let pos_cx_filt = x_weight_1 * shaped_cx + x_weight_2 * old_cx_pos;
@ -401,6 +403,7 @@ pub async fn input_loop(
let mut old_stick_pos = StickPositions::default();
let mut cstick_waveshaping_values = WaveshapingValues::default();
let mut controlstick_waveshaping_values = WaveshapingValues::default();
let mut kalman_state = KalmanState::default();
loop {
current_stick_state = update_stick_states(
@ -416,6 +419,7 @@ pub async fn input_loop(
&mut cstick_waveshaping_values,
&mut old_stick_pos,
&mut raw_stick_values,
&mut kalman_state,
)
.await;

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@ -7,8 +7,8 @@
mod config;
mod filter;
mod gcc_hid;
mod helpers;
mod input;
mod packed_float;
mod stick;
use defmt::{debug, info};

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@ -7,8 +7,8 @@ use libm::{atan2f, cosf, fabs, roundf, sinf, sqrtf};
use crate::{
config::{ControllerConfig, StickConfig, DEFAULT_NOTCH_STATUS},
helpers::ToRegularArray,
input::Stick,
packed_float::ToRegularArray,
};
/// fit order for the linearization