From 249ee968305ae6e8fcf0a10e5cf9cc5826bd81dd Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Wed, 16 Jan 2013 15:13:31 -0800 Subject: [PATCH] altos: Add computation of MicroPeak Kalman correction coefficients Signed-off-by: Keith Packard --- src/Makefile | 1 + src/kalman/kalman_micro.5c | 329 +++++++++++++++++++++++++++++++++++++ src/kalman/load_csv.5c | 21 ++- src/util/make-kalman | 2 + 4 files changed, 349 insertions(+), 4 deletions(-) create mode 100644 src/kalman/kalman_micro.5c diff --git a/src/Makefile b/src/Makefile index 473cc60a..67ad97d1 100644 --- a/src/Makefile +++ b/src/Makefile @@ -8,6 +8,7 @@ vpath make-kalman util vpath make-whiten util vpath kalman.5c kalman vpath kalman_filter.5c kalman +vpath kalman_micro.5c kalman vpath load_csv.5c kalman vpath matrix.5c kalman diff --git a/src/kalman/kalman_micro.5c b/src/kalman/kalman_micro.5c new file mode 100644 index 00000000..266a1182 --- /dev/null +++ b/src/kalman/kalman_micro.5c @@ -0,0 +1,329 @@ +#!/usr/bin/env nickle + +/* + * Copyright © 2013 Keith Packard + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + */ + +autoimport ParseArgs; + +load "load_csv.5c" +import load_csv; + +load "matrix.5c" +import matrix; + +load "kalman_filter.5c" +import kalman; + +load "../util/atmosphere.5c" + +real height_scale = 1.0; +real accel_scale = 1.0; +real speed_scale = 1.0; + +/* + * State: + * + * x[0] = pressure + * x[1] = delta pressure + * x[2] = delta delta pressure + */ + +/* + * Measurement + * + * z[0] = pressure + */ + +real default_σ_m = 5; +real default_σ_h = 2.4; /* pascals */ + +real[3,3] model_error(t, Φ) = multiply_mat_val ((real[3,3]) { + { t**5 / 20, t**4 / 8, t**3 / 6 }, + { t**4 / 8, t**3 / 3, t**2 / 2 }, + { t**3 / 6, t**2 / 2, t } + }, Φ); + +parameters_t param_baro(real t, real σ_m, real σ_h) { + if (σ_m == 0) { + printf ("Using default σ_m\n"); + σ_m = default_σ_m; + } + if (σ_h == 0) { + printf ("Using default σ_h\n"); + σ_h = default_σ_h; + } + + σ_m = imprecise(σ_m) * accel_scale; + σ_h = imprecise(σ_h) * height_scale; + + t = imprecise(t); + return (parameters_t) { +/* + * Equation computing state k from state k-1 + * + * height = height- + velocity- * t + acceleration- * t² / 2 + * velocity = velocity- + acceleration- * t + * acceleration = acceleration- + */ + .a = (real[3,3]) { + { 1, t * height_scale / speed_scale , t**2/2 * height_scale / accel_scale }, + { 0, 1, t * speed_scale / accel_scale }, + { 0, 0, 1 } + }, +/* + * Model error covariance. The only inaccuracy in the + * model is the assumption that acceleration is constant + */ + .q = model_error (t, σ_m**2), + +/* + * Measurement error covariance + * Our sensors are independent, so + * this matrix is zero off-diagonal + */ + .r = (real[1,1]) { + { σ_h ** 2 }, + }, +/* + * Extract measurements from state, + * this just pulls out the height + * values. + */ + .h = (real[1,3]) { + { 1, 0, 0 }, + }, + }; +} + +bool just_kalman = true; +real accel_input_scale = 1; + +real error_avg; + +void update_error_avg(real e) { + if (e < 0) + e = -e; + +# if (e > 1000) +# e = 1000; + + error_avg -= error_avg / 8; + error_avg += (e * e) / 8; +} + +void run_flight(string name, file f, bool summary, real σ_m, real σ_h) { + state_t current_both = { + .x = (real[3]) { 0, 0, 0 }, + .p = (real[3,3]) { { 0 ... } ... }, + }; + state_t current_accel = current_both; + state_t current_baro = current_both; + real t; + real kalman_apogee_time = -1; + real kalman_apogee = 0; + real raw_apogee_time_first; + real raw_apogee_time_last; + real raw_apogee = 0; + real speed = 0; + real prev_acceleration = 0; + real height, max_height = 0; + state_t apogee_state; + parameters_fast_t fast_baro; + real fast_delta_t = 0; + bool fast = true; + int speed_lock = 0; + + error_avg = 0; + for (;;) { + record_t record = parse_record(f, 1.0); + if (record.done) + break; + if (is_uninit(&t)) + t = record.time; + real delta_t = record.time - t; + if (delta_t < 0.096) + continue; +# delta_t = 0.096; /* pretend that we're getting micropeak-rate data */ +# record.time = record.time + delta_t; + t = record.time; + if (record.height > raw_apogee) { + raw_apogee_time_first = record.time; + raw_apogee = record.height; + } + if (record.height == raw_apogee) + raw_apogee_time_last = record.time; + + real pressure = record.pressure; + + if (current_baro.x[0] == 0) + current_baro.x[0] = pressure; + + vec_t z_baro = (real[1]) { record.pressure * height_scale }; + + real error_h; + + if (fast) { + if (delta_t != fast_delta_t) { + fast_baro = convert_to_fast(param_baro(delta_t, σ_m, σ_h)); + fast_delta_t = delta_t; + } + + current_baro.x = predict_fast(current_baro.x, fast_baro); + error_h = current_baro.x[0] - pressure; + current_baro.x = correct_fast(current_baro.x, z_baro, fast_baro); + } else { + parameters_t p_baro = param_baro(delta_t, σ_m, σ_h); + + state_t pred_baro = predict(current_baro, p_baro); + error_h = current_baro.x[0] - pressure; + state_t next_baro = correct(pred_baro, z_baro, p_baro); + current_baro = next_baro; + } + + update_error_avg(error_h); + + /* Don't check for maximum altitude if we're accelerating upwards */ + if (current_baro.x[2] / accel_scale < -2 * σ_m) + speed_lock = 10; + else if (speed_lock > 0) + speed_lock--; + + height = pressure_to_altitude(current_baro.x[0] / height_scale); + if (speed_lock == 0 && height > max_height) + max_height = height; + + printf ("%16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %16.8f %d %d\n", + record.time, + record.pressure, + pressure_to_altitude(record.pressure), + current_baro.x[0] / height_scale, + current_baro.x[1] / speed_scale, + current_baro.x[2] / accel_scale, + height, + max_height, + error_h, + error_avg, + error_avg > 50000 ? 0 : 95000, + speed_lock > 0 ? 0 : 4500); + + if (kalman_apogee_time < 0) { + if (current_baro.x[1] > 1) { + kalman_apogee = current_both.x[0]; + kalman_apogee_time = record.time; + } + } + } + real raw_apogee_time = (raw_apogee_time_last + raw_apogee_time_first) / 2; + if (summary && !just_kalman) { + printf("%s: kalman (%8.2f m %6.2f s) raw (%8.2f m %6.2f s) error %6.2f s\n", + name, + kalman_apogee, kalman_apogee_time, + raw_apogee, raw_apogee_time, + kalman_apogee_time - raw_apogee_time); + } +} + +void main() { + bool summary = false; + int user_argind = 1; + real time_step = 0.01; + string compute = "none"; + string prefix = "AO_K"; + real σ_m = default_σ_m; + real σ_h = default_σ_h; + + ParseArgs::argdesc argd = { + .args = { + { .var = { .arg_flag = &summary }, + .abbr = 's', + .name = "summary", + .desc = "Print a summary of the flight" }, + { .var = { .arg_real = &time_step, }, + .abbr = 't', + .name = "time", + .expr_name = "", + .desc = "Set time step for convergence" }, + { .var = { .arg_string = &prefix }, + .abbr = 'p', + .name = "prefix", + .expr_name = "", + .desc = "Prefix for compute output" }, + { .var = { .arg_string = &compute }, + .abbr = 'c', + .name = "compute", + .expr_name = "{baro,none}", + .desc = "Compute Kalman factor through convergence" }, + { .var = { .arg_real = &σ_m }, + .abbr = 'M', + .name = "model", + .expr_name = "", + .desc = "Model co-variance for acceleration" }, + { .var = { .arg_real = &σ_h }, + .abbr = 'H', + .name = "height", + .expr_name = "", + .desc = "Measure co-variance for height" }, + }, + + .unknown = &user_argind, + }; + + ParseArgs::parseargs(&argd, &argv); + + if (compute != "none") { + parameters_t param; + + printf ("/* Kalman matrix for micro %s\n", compute); + printf (" * step = %f\n", time_step); + printf (" * σ_m = %f\n", σ_m); + switch (compute) { + case "baro": + printf (" * σ_h = %f\n", σ_h); + param = param_baro(time_step, σ_m, σ_h); + break; + } + printf (" */\n\n"); + mat_t k = converge(param); + int[] d = dims(k); + int time_inc = floor(1/time_step + 0.5); + for (int i = 0; i < d[0]; i++) + for (int j = 0; j < d[1]; j++) { + string name; + if (d[1] == 1) + name = sprintf("%s_K%d_%d", prefix, i, time_inc); + else + name = sprintf("%s_K%d%d_%d", prefix, i, j, time_inc); + printf ("#define %s to_fix32(%12.10f)\n", name, k[i,j]); + } + printf ("\n"); + exit(0); + } + string[dim(argv) - user_argind] rest = { [i] = argv[i+user_argind] }; + + # height_scale = accel_scale = speed_scale = 1; + + if (dim(rest) == 0) + run_flight("", stdin, summary, σ_m, σ_h); + else { + for (int i = 0; i < dim(rest); i++) { + twixt(file f = File::open(rest[i], "r"); File::close(f)) { + run_flight(rest[i], f, summary, σ_m, σ_h); + } + } + } +} +main(); diff --git a/src/kalman/load_csv.5c b/src/kalman/load_csv.5c index 15e83166..0086c6db 100644 --- a/src/kalman/load_csv.5c +++ b/src/kalman/load_csv.5c @@ -31,6 +31,7 @@ namespace load_csv { real time; real height; real acceleration; + real pressure; } record_t; public record_t parse_record(file f, real accel_scale) { @@ -40,16 +41,28 @@ namespace load_csv { int time_off = 4; int height_off = 11; int accel_off = 8; - if (string_to_integer(data[0]) == 2) { + int pres_off = 9; + switch (string_to_integer(data[0])) { + case 2: time_off = 4; accel_off = 9; + pres_off = 10; height_off = 12; + break; + case 5: + time_off = 4; + accel_off = 10; + pres_off = 11; + height_off = 13; + break; } return (record_t) { .done = false, - .time = string_to_real(data[time_off]), - .height = imprecise(string_to_real(data[height_off])), - .acceleration = imprecise(string_to_real(data[accel_off]) * accel_scale) }; + .time = string_to_real(data[time_off]), + .height = imprecise(string_to_real(data[height_off])), + .acceleration = imprecise(string_to_real(data[accel_off]) * accel_scale), + .pressure = imprecise(string_to_real(data[pres_off])) + }; } public void dump(file f) { diff --git a/src/util/make-kalman b/src/util/make-kalman index fd33bab0..580a4515 100644 --- a/src/util/make-kalman +++ b/src/util/make-kalman @@ -6,6 +6,7 @@ SIGMA_BOTH="-M 2 -H 6 -A 2" SIGMA_BARO="-M 2 -H 6 -A 2" SIGMA_ACCEL="-M 2 -H 4 -A 4" SIGMA_BOTH_NOISY_ACCEL="-M 2 -H 6 -A 3" +SIGMA_MICRO="-M 10" echo '#if NOISY_ACCEL' echo @@ -39,3 +40,4 @@ nickle kalman.5c -p AO_BARO -c baro -t 0.01 $SIGMA_BARO nickle kalman.5c -p AO_BARO -c baro -t 0.1 $SIGMA_BARO nickle kalman.5c -p AO_BARO -c baro -t 1 $SIGMA_BARO +nickle kalman_micro.5c -p AO_MK_BARO -c baro -t 0.096 $SIGMA_MICRO \ No newline at end of file -- 2.30.2