diff options
Diffstat (limited to 'src/modules/att_pos_estimator_ekf/KalmanNav.cpp')
| -rw-r--r-- | src/modules/att_pos_estimator_ekf/KalmanNav.cpp | 198 |
1 files changed, 110 insertions, 88 deletions
diff --git a/src/modules/att_pos_estimator_ekf/KalmanNav.cpp b/src/modules/att_pos_estimator_ekf/KalmanNav.cpp index c3836bdfa..97d7fdd75 100644 --- a/src/modules/att_pos_estimator_ekf/KalmanNav.cpp +++ b/src/modules/att_pos_estimator_ekf/KalmanNav.cpp @@ -1,6 +1,6 @@ /**************************************************************************** * - * Copyright (C) 2012 PX4 Development Team. All rights reserved. + * Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -40,6 +40,7 @@ #include <poll.h> #include "KalmanNav.hpp" +#include <systemlib/err.h> // constants // Titterton pg. 52 @@ -58,14 +59,17 @@ KalmanNav::KalmanNav(SuperBlock *parent, const char *name) : P0(9, 9), V(6, 6), // attitude measurement ekf matrices - HAtt(6, 9), - RAtt(6, 6), + HAtt(4, 9), + RAtt(4, 4), // position measurement ekf matrices HPos(6, 9), RPos(6, 6), // attitude representations C_nb(), q(), + _accel_sub(-1), + _gyro_sub(-1), + _mag_sub(-1), // subscriptions _sensors(&getSubscriptions(), ORB_ID(sensor_combined), 5), // limit to 200 Hz _gps(&getSubscriptions(), ORB_ID(vehicle_gps_position), 100), // limit to 10 Hz @@ -123,8 +127,19 @@ KalmanNav::KalmanNav(SuperBlock *parent, const char *name) : lon = 0.0f; alt = 0.0f; - // initialize quaternions - q = Quaternion(EulerAngles(phi, theta, psi)); + // gyro, accel and mag subscriptions + _gyro_sub = orb_subscribe(ORB_ID(sensor_gyro)); + _accel_sub = orb_subscribe(ORB_ID(sensor_accel)); + _mag_sub = orb_subscribe(ORB_ID(sensor_mag)); + + struct accel_report accel; + orb_copy(ORB_ID(sensor_accel), _accel_sub, &accel); + + struct mag_report mag; + orb_copy(ORB_ID(sensor_mag), _mag_sub, &mag); + + // initialize rotation quaternion with a single raw sensor measurement + q = init(accel.x, accel.y, accel.z, mag.x, mag.y, mag.z); // initialize dcm C_nb = Dcm(q); @@ -141,6 +156,45 @@ KalmanNav::KalmanNav(SuperBlock *parent, const char *name) : updateParams(); } +math::Quaternion KalmanNav::init(float ax, float ay, float az, float mx, float my, float mz) +{ + float initialRoll, initialPitch; + float cosRoll, sinRoll, cosPitch, sinPitch; + float magX, magY; + float initialHdg, cosHeading, sinHeading; + + initialRoll = atan2(-ay, -az); + initialPitch = atan2(ax, -az); + + cosRoll = cosf(initialRoll); + sinRoll = sinf(initialRoll); + cosPitch = cosf(initialPitch); + sinPitch = sinf(initialPitch); + + magX = mx * cosPitch + my * sinRoll * sinPitch + mz * cosRoll * sinPitch; + + magY = my * cosRoll - mz * sinRoll; + + initialHdg = atan2f(-magY, magX); + + cosRoll = cosf(initialRoll * 0.5f); + sinRoll = sinf(initialRoll * 0.5f); + + cosPitch = cosf(initialPitch * 0.5f); + sinPitch = sinf(initialPitch * 0.5f); + + cosHeading = cosf(initialHdg * 0.5f); + sinHeading = sinf(initialHdg * 0.5f); + + float q0 = cosRoll * cosPitch * cosHeading + sinRoll * sinPitch * sinHeading; + float q1 = sinRoll * cosPitch * cosHeading - cosRoll * sinPitch * sinHeading; + float q2 = cosRoll * sinPitch * cosHeading + sinRoll * cosPitch * sinHeading; + float q3 = cosRoll * cosPitch * sinHeading - sinRoll * sinPitch * cosHeading; + + return math::Quaternion(q0, q1, q2, q3); + +} + void KalmanNav::update() { using namespace math; @@ -181,8 +235,8 @@ void KalmanNav::update() if (correctAtt() == ret_ok) _attitudeInitCounter++; if (_attitudeInitCounter > 100) { - printf("[kalman_demo] initialized EKF attitude\n"); - printf("phi: %8.4f, theta: %8.4f, psi: %8.4f\n", + warnx("initialized EKF attitude\n"); + warnx("phi: %8.4f, theta: %8.4f, psi: %8.4f\n", double(phi), double(theta), double(psi)); _attitudeInitialized = true; } @@ -202,13 +256,13 @@ void KalmanNav::update() setLonDegE7(_gps.lon); setAltE3(_gps.alt); _positionInitialized = true; - printf("[kalman_demo] initialized EKF state with GPS\n"); - printf("vN: %8.4f, vE: %8.4f, vD: %8.4f, lat: %8.4f, lon: %8.4f, alt: %8.4f\n", + warnx("initialized EKF state with GPS\n"); + warnx("vN: %8.4f, vE: %8.4f, vD: %8.4f, lat: %8.4f, lon: %8.4f, alt: %8.4f\n", double(vN), double(vE), double(vD), lat, lon, alt); } - // prediciton step + // prediction step // using sensors timestamp so we can account for packet lag float dt = (_sensors.timestamp - _predictTimeStamp) / 1.0e6f; //printf("dt: %15.10f\n", double(dt)); @@ -233,7 +287,7 @@ void KalmanNav::update() // attitude correction step if (_attitudeInitialized // initialized && sensorsUpdate // new data - && _sensors.timestamp - _attTimeStamp > 1e6 / 20 // 20 Hz + && _sensors.timestamp - _attTimeStamp > 1e6 / 50 // 50 Hz ) { _attTimeStamp = _sensors.timestamp; correctAtt(); @@ -480,26 +534,32 @@ int KalmanNav::correctAtt() // trig float cosPhi = cosf(phi); float cosTheta = cosf(theta); - float cosPsi = cosf(psi); + // float cosPsi = cosf(psi); float sinPhi = sinf(phi); float sinTheta = sinf(theta); - float sinPsi = sinf(psi); - - // mag measurement - Vector3 zMag(_sensors.magnetometer_ga); - //float magNorm = zMag.norm(); - zMag = zMag.unit(); + // float sinPsi = sinf(psi); // mag predicted measurement // choosing some typical magnetic field properties, // TODO dip/dec depend on lat/ lon/ time - float dip = _magDip.get() / M_RAD_TO_DEG_F; // dip, inclination with level + //float dip = _magDip.get() / M_RAD_TO_DEG_F; // dip, inclination with level float dec = _magDec.get() / M_RAD_TO_DEG_F; // declination, clockwise rotation from north - float bN = cosf(dip) * cosf(dec); - float bE = cosf(dip) * sinf(dec); - float bD = sinf(dip); - Vector3 bNav(bN, bE, bD); - Vector3 zMagHat = (C_nb.transpose() * bNav).unit(); + + // compensate roll and pitch, but not yaw + // XXX take the vectors out of the C_nb matrix to avoid singularities + math::Dcm C_rp(math::EulerAngles(phi, theta, 0.0f));//C_nb.transpose(); + + // mag measurement + Vector3 magBody(_sensors.magnetometer_ga); + + // transform to earth frame + Vector3 magNav = C_rp * magBody; + + // calculate error between estimate and measurement + // apply declination correction for true heading as well. + float yMag = -atan2f(magNav(1),magNav(0)) - psi - dec; + if (yMag > M_PI_F) yMag -= 2*M_PI_F; + if (yMag < -M_PI_F) yMag += 2*M_PI_F; // accel measurement Vector3 zAccel(_sensors.accelerometer_m_s2); @@ -512,9 +572,9 @@ int KalmanNav::correctAtt() bool ignoreAccel = fabsf(accelMag - _g.get()) > 1.1f; if (ignoreAccel) { + RAttAdjust(1, 1) = 1.0e10; + RAttAdjust(2, 2) = 1.0e10; RAttAdjust(3, 3) = 1.0e10; - RAttAdjust(4, 4) = 1.0e10; - RAttAdjust(5, 5) = 1.0e10; } else { //printf("correcting attitude with accel\n"); @@ -523,58 +583,25 @@ int KalmanNav::correctAtt() // accel predicted measurement Vector3 zAccelHat = (C_nb.transpose() * Vector3(0, 0, -_g.get())).unit(); - // combined measurement - Vector zAtt(6); - Vector zAttHat(6); + // calculate residual + Vector y(4); + y(0) = yMag; + y(1) = zAccel(0) - zAccelHat(0); + y(2) = zAccel(1) - zAccelHat(1); + y(3) = zAccel(2) - zAccelHat(2); - for (int i = 0; i < 3; i++) { - zAtt(i) = zMag(i); - zAtt(i + 3) = zAccel(i); - zAttHat(i) = zMagHat(i); - zAttHat(i + 3) = zAccelHat(i); - } + // HMag + HAtt(0, 2) = 1; - // HMag , HAtt (0-2,:) - float tmp1 = - cosPsi * cosTheta * bN + - sinPsi * cosTheta * bE - - sinTheta * bD; - HAtt(0, 1) = -( - cosPsi * sinTheta * bN + - sinPsi * sinTheta * bE + - cosTheta * bD - ); - HAtt(0, 2) = -cosTheta * (sinPsi * bN - cosPsi * bE); - HAtt(1, 0) = - (cosPhi * cosPsi * sinTheta + sinPhi * sinPsi) * bN + - (cosPhi * sinPsi * sinTheta - sinPhi * cosPsi) * bE + - cosPhi * cosTheta * bD; - HAtt(1, 1) = sinPhi * tmp1; - HAtt(1, 2) = -( - (sinPhi * sinPsi * sinTheta + cosPhi * cosPsi) * bN - - (sinPhi * cosPsi * sinTheta - cosPhi * sinPsi) * bE - ); - HAtt(2, 0) = -( - (sinPhi * cosPsi * sinTheta - cosPhi * sinPsi) * bN + - (sinPhi * sinPsi * sinTheta + cosPhi * cosPsi) * bE + - (sinPhi * cosTheta) * bD - ); - HAtt(2, 1) = cosPhi * tmp1; - HAtt(2, 2) = -( - (cosPhi * sinPsi * sinTheta - sinPhi * cosTheta) * bN - - (cosPhi * cosPsi * sinTheta + sinPhi * sinPsi) * bE - ); - - // HAccel , HAtt (3-5,:) - HAtt(3, 1) = cosTheta; - HAtt(4, 0) = -cosPhi * cosTheta; - HAtt(4, 1) = sinPhi * sinTheta; - HAtt(5, 0) = sinPhi * cosTheta; - HAtt(5, 1) = cosPhi * sinTheta; + // HAccel + HAtt(1, 1) = cosTheta; + HAtt(2, 0) = -cosPhi * cosTheta; + HAtt(2, 1) = sinPhi * sinTheta; + HAtt(3, 0) = sinPhi * cosTheta; + HAtt(3, 1) = cosPhi * sinTheta; // compute correction // http://en.wikipedia.org/wiki/Extended_Kalman_filter - Vector y = zAtt - zAttHat; // residual Matrix S = HAtt * P * HAtt.transpose() + RAttAdjust; // residual covariance Matrix K = P * HAtt.transpose() * S.inverse(); Vector xCorrect = K * y; @@ -585,7 +612,7 @@ int KalmanNav::correctAtt() if (isnan(val) || isinf(val)) { // abort correction and return - printf("[kalman_demo] numerical failure in att correction\n"); + warnx("numerical failure in att correction\n"); // reset P matrix to P0 P = P0; return ret_error; @@ -615,11 +642,8 @@ int KalmanNav::correctAtt() float beta = y.dot(S.inverse() * y); if (beta > _faultAtt.get()) { - printf("fault in attitude: beta = %8.4f\n", (double)beta); - printf("y:\n"); y.print(); - printf("zMagHat:\n"); zMagHat.print(); - printf("zMag:\n"); zMag.print(); - printf("bNav:\n"); bNav.print(); + warnx("fault in attitude: beta = %8.4f", (double)beta); + warnx("y:\n"); y.print(); } // update quaternions from euler @@ -652,9 +676,9 @@ int KalmanNav::correctPos() for (size_t i = 0; i < xCorrect.getRows(); i++) { float val = xCorrect(i); - if (isnan(val) || isinf(val)) { + if (!isfinite(val)) { // abort correction and return - printf("[kalman_demo] numerical failure in gps correction\n"); + warnx("numerical failure in gps correction\n"); // fallback to GPS vN = _gps.vel_n_m_s; vE = _gps.vel_e_m_s; @@ -685,8 +709,8 @@ int KalmanNav::correctPos() static int counter = 0; if (beta > _faultPos.get() && (counter % 10 == 0)) { - printf("fault in gps: beta = %8.4f\n", (double)beta); - printf("Y/N: vN: %8.4f, vE: %8.4f, lat: %8.4f, lon: %8.4f, alt: %8.4f\n", + warnx("fault in gps: beta = %8.4f", (double)beta); + warnx("Y/N: vN: %8.4f, vE: %8.4f, lat: %8.4f, lon: %8.4f, alt: %8.4f", double(y(0) / sqrtf(RPos(0, 0))), double(y(1) / sqrtf(RPos(1, 1))), double(y(2) / sqrtf(RPos(2, 2))), @@ -722,8 +746,6 @@ void KalmanNav::updateParams() if (noiseMagSq < noiseMin) noiseMagSq = noiseMin; RAtt(0, 0) = noiseMagSq; // normalized direction - RAtt(1, 1) = noiseMagSq; - RAtt(2, 2) = noiseMagSq; // accelerometer noise float noiseAccelSq = _rAccel.get() * _rAccel.get(); @@ -731,9 +753,9 @@ void KalmanNav::updateParams() // bound noise to prevent singularities if (noiseAccelSq < noiseMin) noiseAccelSq = noiseMin; - RAtt(3, 3) = noiseAccelSq; // normalized direction - RAtt(4, 4) = noiseAccelSq; - RAtt(5, 5) = noiseAccelSq; + RAtt(1, 1) = noiseAccelSq; // normalized direction + RAtt(2, 2) = noiseAccelSq; + RAtt(3, 3) = noiseAccelSq; // gps noise float R = R0 + float(alt); |