fly316/PX4-Autopilot
7
0
Fork 0
mirror of https://gitee.com/mirrors_PX4/PX4-Autopilot.git synced 2026-06-28 03:20:34 +08:00
Code Issues Packages Projects Releases Wiki Activity

ekf2: terrain flow - migrate to Symforce

Browse Source
This commit is contained in:
bresch
2023-01-16 16:37:03 +01:00
committed by Daniel Agar
parent 3f842f01a0
commit b4b48cae75
5 changed files with 277 additions and 169 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/modules/ekf2/EKF/python/ekf_derivation/derivation_terrain_estimator.py
+91
View File
@@ -0,0 +1,91 @@
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Copyright (c) 2023 PX4 Development Team
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
3. Neither the name PX4 nor the names of its contributors may be
used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
File: derivation_terrain_estimator.py
Description:
"""
import symforce.symbolic as sf
from derivation_utils import *
def predict_opt_flow(
terrain_vpos: sf.Scalar,
q_att: sf.V4,
v: sf.V3,
pos_z: sf.Scalar,
epsilon : sf.Scalar
):
R_to_earth = quat_to_rot(q_att)
flow_pred = sf.V2()
dist = - (pos_z - terrain_vpos)
dist = add_epsilon_sign(dist, dist, epsilon)
flow_pred[0] = -v[1] / dist * R_to_earth[2, 2]
flow_pred[1] = v[0] / dist * R_to_earth[2, 2]
return flow_pred
def terr_est_compute_flow_xy_innov_var_and_hx(
terrain_vpos: sf.Scalar,
P: sf.Scalar,
q_att: sf.V4,
v: sf.V3,
pos_z: sf.Scalar,
R: sf.Scalar,
epsilon : sf.Scalar
):
flow_pred = predict_opt_flow(terrain_vpos, q_att, v, pos_z, epsilon)
Hx = sf.V1(flow_pred[0]).jacobian(terrain_vpos)
Hy = sf.V1(flow_pred[1]).jacobian(terrain_vpos)
innov_var = sf.V2()
innov_var[0] = (Hx * P * Hx.T + R)[0,0]
innov_var[1] = (Hy * P * Hy.T + R)[0,0]
return (innov_var, Hx[0, 0])
def terr_est_compute_flow_y_innov_var_and_h(
terrain_vpos: sf.Scalar,
P: sf.Scalar,
q_att: sf.V4,
v: sf.V3,
pos_z: sf.Scalar,
R: sf.Scalar,
epsilon : sf.Scalar
):
flow_pred = predict_opt_flow(terrain_vpos, q_att, v, pos_z, epsilon)
Hy = sf.V1(flow_pred[1]).jacobian(terrain_vpos)
innov_var = (Hy * P * Hy.T + R)[0,0]
return (innov_var, Hy[0, 0])
print("Derive terrain estimator equations...")
generate_px4_function(terr_est_compute_flow_xy_innov_var_and_hx, output_names=["innov_var", "H"])
generate_px4_function(terr_est_compute_flow_y_innov_var_and_h, output_names=["innov_var", "H"])
src/modules/ekf2/EKF/python/ekf_derivation/generated/terr_est_compute_flow_xy_innov_var_and_hx.h
+66
View File
@@ -0,0 +1,66 @@
// -----------------------------------------------------------------------------
// This file was autogenerated by symforce from template:
// backends/cpp/templates/function/FUNCTION.h.jinja
// Do NOT modify by hand.
// -----------------------------------------------------------------------------
#pragma once
#include <matrix/math.hpp>
namespace sym {
/**
* This function was autogenerated from a symbolic function. Do not modify by hand.
*
* Symbolic function: terr_est_compute_flow_xy_innov_var_and_hx
*
* Args:
* terrain_vpos: Scalar
* P: Scalar
* q_att: Matrix41
* v: Matrix31
* pos_z: Scalar
* R: Scalar
* epsilon: Scalar
*
* Outputs:
* innov_var: Matrix21
* H: Scalar
*/
template <typename Scalar>
void TerrEstComputeFlowXyInnovVarAndHx(const Scalar terrain_vpos, const Scalar P,
const matrix::Matrix<Scalar, 4, 1>& q_att,
const matrix::Matrix<Scalar, 3, 1>& v, const Scalar pos_z,
const Scalar R, const Scalar epsilon,
matrix::Matrix<Scalar, 2, 1>* const innov_var = nullptr,
Scalar* const H = nullptr) {
// Total ops: 28
// Input arrays
// Intermediate terms (4)
const Scalar _tmp0 = std::pow(q_att(0, 0), Scalar(2)) - std::pow(q_att(1, 0), Scalar(2)) -
std::pow(q_att(2, 0), Scalar(2)) + std::pow(q_att(3, 0), Scalar(2));
const Scalar _tmp1 = pos_z - terrain_vpos;
const Scalar _tmp2 =
-_tmp1 + epsilon * (2 * math::min<Scalar>(0, -(((_tmp1) > 0) - ((_tmp1) < 0))) + 1);
const Scalar _tmp3 = P * std::pow(_tmp0, Scalar(2)) / std::pow(_tmp2, Scalar(4));
// Output terms (2)
if (innov_var != nullptr) {
matrix::Matrix<Scalar, 2, 1>& _innov_var = (*innov_var);
_innov_var(0, 0) = R + _tmp3 * std::pow(v(1, 0), Scalar(2));
_innov_var(1, 0) = R + _tmp3 * std::pow(v(0, 0), Scalar(2));
}
if (H != nullptr) {
Scalar& _H = (*H);
_H = _tmp0 * v(1, 0) / std::pow(_tmp2, Scalar(2));
}
} // NOLINT(readability/fn_size)
// NOLINTNEXTLINE(readability/fn_size)
} // namespace sym
src/modules/ekf2/EKF/python/ekf_derivation/generated/terr_est_compute_flow_y_innov_var_and_h.h
+65
View File
@@ -0,0 +1,65 @@
// -----------------------------------------------------------------------------
// This file was autogenerated by symforce from template:
// backends/cpp/templates/function/FUNCTION.h.jinja
// Do NOT modify by hand.
// -----------------------------------------------------------------------------
#pragma once
#include <matrix/math.hpp>
namespace sym {
/**
* This function was autogenerated from a symbolic function. Do not modify by hand.
*
* Symbolic function: terr_est_compute_flow_y_innov_var_and_h
*
* Args:
* terrain_vpos: Scalar
* P: Scalar
* q_att: Matrix41
* v: Matrix31
* pos_z: Scalar
* R: Scalar
* epsilon: Scalar
*
* Outputs:
* innov_var: Scalar
* H: Scalar
*/
template <typename Scalar>
void TerrEstComputeFlowYInnovVarAndH(const Scalar terrain_vpos, const Scalar P,
const matrix::Matrix<Scalar, 4, 1>& q_att,
const matrix::Matrix<Scalar, 3, 1>& v, const Scalar pos_z,
const Scalar R, const Scalar epsilon,
Scalar* const innov_var = nullptr, Scalar* const H = nullptr) {
// Total ops: 26
// Input arrays
// Intermediate terms (3)
const Scalar _tmp0 = std::pow(q_att(0, 0), Scalar(2)) - std::pow(q_att(1, 0), Scalar(2)) -
std::pow(q_att(2, 0), Scalar(2)) + std::pow(q_att(3, 0), Scalar(2));
const Scalar _tmp1 = pos_z - terrain_vpos;
const Scalar _tmp2 =
-_tmp1 + epsilon * (2 * math::min<Scalar>(0, -(((_tmp1) > 0) - ((_tmp1) < 0))) + 1);
// Output terms (2)
if (innov_var != nullptr) {
Scalar& _innov_var = (*innov_var);
_innov_var =
P * std::pow(_tmp0, Scalar(2)) * std::pow(v(0, 0), Scalar(2)) / std::pow(_tmp2, Scalar(4)) +
R;
}
if (H != nullptr) {
Scalar& _H = (*H);
_H = -_tmp0 * v(0, 0) / std::pow(_tmp2, Scalar(2));
}
} // NOLINT(readability/fn_size)
// NOLINTNEXTLINE(readability/fn_size)
} // namespace sym
src/modules/ekf2/EKF/python/terrain_flow_derivation/derive_terrain_flow.py
-97
View File
@@ -1,97 +0,0 @@
"""
This script calculates the observation scalars (H matrix) for fusing optical flow
measurements for terrain estimation.
@author: roman
"""
from sympy import *
# q: quaternion describing rotation from frame 1 to frame 2
# returns a rotation matrix derived form q which describes the same
# rotation
def quat2Rot(q):
q0 = q[0]
q1 = q[1]
q2 = q[2]
q3 = q[3]
Rot = Matrix([[q0**2 + q1**2 - q2**2 - q3**2, 2*(q1*q2 - q0*q3), 2*(q1*q3 + q0*q2)],
[2*(q1*q2 + q0*q3), q0**2 - q1**2 + q2**2 - q3**2, 2*(q2*q3 - q0*q1)],
[2*(q1*q3-q0*q2), 2*(q2*q3 + q0*q1), q0**2 - q1**2 - q2**2 + q3**2]])
return Rot
# take an expression calculated by the cse() method and write the expression
# into a text file in C format
def write_simplified(P_touple, filename, out_name):
subs = P_touple[0]
P = Matrix(P_touple[1])
fd = open(filename, 'a')
is_vector = P.shape[0] == 1 or P.shape[1] == 1
# write sub expressions
for index, item in enumerate(subs):
fd.write('float ' + str(item[0]) + ' = ' + str(item[1]) + ';\n')
# write actual matrix values
fd.write('\n')
if not is_vector:
iterator = range(0,sqrt(len(P)), 1)
for row in iterator:
for column in iterator:
fd.write(out_name + '(' + str(row) + ',' + str(column) + ') = ' + str(P[row, column]) + ';\n')
else:
iterator = range(0, len(P), 1)
for item in iterator:
fd.write(out_name + '(' + str(item) + ') = ' + str(P[item]) + ';\n')
fd.write('\n\n')
fd.close()
########## Symbolic variable definition #######################################
# vehicle velocity
v_x = Symbol("v_x", real=True) # vehicle body x velocity
v_y = Symbol("v_y", real=True) # vehicle body y velocity
# unit quaternion describing vehicle attitude, qw is real part
qw = Symbol("q0", real=True)
qx = Symbol("q1", real=True)
qy = Symbol("q2", real=True)
qz = Symbol("q3", real=True)
q_att = Matrix([qw, qx, qy, qz])
# terrain vertial position in local NED frame
_terrain_vpos = Symbol("_terrain_vpos", real=True)
_terrain_var = Symbol("_terrain_var", real=True)
# vehicle vertical position in local NED frame
pos_z = Symbol("z", real=True)
R_body_to_earth = quat2Rot(q_att)
# Optical flow around x axis
flow_x = -v_y / (_terrain_vpos - pos_z) * R_body_to_earth[2,2]
# Calculate observation scalar
H_x = Matrix([flow_x]).jacobian(Matrix([_terrain_vpos]))
H_x_simple = cse(H_x, symbols('t0:30'))
# Optical flow around y axis
flow_y = v_x / (_terrain_vpos - pos_z) * R_body_to_earth[2,2]
# Calculate observation scalar
H_y = Matrix([flow_y]).jacobian(Matrix([_terrain_vpos]))
H_y_simple = cse(H_y, symbols('t0:30'))
write_simplified(H_x_simple, "flow_x_observation.txt", "Hx")
write_simplified(H_y_simple, "flow_y_observation.txt", "Hy")