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Fixed wrapping issue. #5

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merged 6 commits into from
Jan 16, 2024
Merged

Fixed wrapping issue. #5

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71758a6
Fixed wrapping issue.
iandareid Nov 6, 2023
acd7317
Cleaned wrapping functions.
iandareid Nov 15, 2023
123afe1
Fixed the wrap syntax issue
iandareid Nov 28, 2023
583dc7f
Added back the low pass filter for the gyro.
iandareid Nov 28, 2023
a109542
Added the warning messages back into the estimator.
iandareid Nov 28, 2023
9c5aa72
Cleaned up some of the comments and calculations.
iandareid Nov 28, 2023
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44 changes: 21 additions & 23 deletions rosplane/src/estimator_example.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,11 @@ float radians(float degrees)
return M_PI*degrees/180.0;
}

double wrap_within_180(double fixed_heading, double wrapped_heading) {
// wrapped_heading - number_of_times_to_wrap * 2pi
return wrapped_heading - floor((wrapped_heading - fixed_heading) / (2 * M_PI) + 0.5) * 2 * M_PI;
}

estimator_example::estimator_example() :
estimator_base(),
xhat_a_(Eigen::Vector2f::Zero()),
Expand Down Expand Up @@ -81,8 +86,8 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o
}

// low pass filter gyros to estimate angular rates
lpf_gyro_x_ = input.gyro_x;
lpf_gyro_y_ = input.gyro_y; // alpha_*lpf_gyro_y_ + (1 - alpha_)*input.gyro_y;
lpf_gyro_x_ = alpha_*lpf_gyro_x_ + (1 - alpha_)*input.gyro_x;
lpf_gyro_y_ = alpha_*lpf_gyro_y_ + (1 - alpha_)*input.gyro_y;
lpf_gyro_z_ = alpha_*lpf_gyro_z_ + (1 - alpha_)*input.gyro_z;

float phat = lpf_gyro_x_;
Expand Down Expand Up @@ -170,18 +175,18 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o
-params.gravity*cp*ct, -rhat*Vahat*st - phat*Vahat*ct + params.gravity*sp*st,
params.gravity*sp*ct, (qhat*Vahat + params.gravity*cp) * st;

// This calculates the Kalman Gain for all of the attitude states at once rather than one at a time.

Eigen::Vector3f y;

y << lpf_accel_x_, lpf_accel_y_, lpf_accel_z_;

Eigen::MatrixXf S_inv = (R_accel_ + C_a_ * P_a_ * C_a_.transpose()).inverse();
Eigen::MatrixXf L_a_ = P_a_ * C_a_.transpose() * S_inv;
Eigen::MatrixXf temp = Eigen::MatrixXf::Identity(2,2) - L_a_ * C_a_;

if ((y-h_a_).transpose() * S_inv * (y-h_a_) < 10000000.0){
Eigen::MatrixXf L = P_a_ * C_a_.transpose() * S_inv;
Eigen::MatrixXf temp = Eigen::MatrixXf::Identity(2,2) - L * C_a_;
P_a_ = temp * P_a_ * temp.transpose() + L * R_accel_ * L.transpose();
xhat_a_ = xhat_a_ + L * (y - h_a_);
}
P_a_ = temp * P_a_ * temp.transpose() + L_a_ * R_accel_ *L_a_.transpose();
xhat_a_ = xhat_a_ + L_a_ * (y - h_a_);

check_xhat_a();

Expand All @@ -199,8 +204,6 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o
for (int i = 0; i < N_; i++)
{

// float pn = xhat_p_(0);
// float pe = xhat_p_(1);
float Vg = xhat_p_(2);
float chi = xhat_p_(3);
float wn = xhat_p_(4);
Expand Down Expand Up @@ -237,17 +240,15 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o

P_p_ = (A_d_*P_p_*A_d_.transpose() + Q_p_*pow(params.Ts/N_, 2));
}

while(xhat_p_(3) > radians(180.0f)) xhat_p_(3) = xhat_p_(3) - radians(360.0f);
while(xhat_p_(3) < radians(-180.0f)) xhat_p_(3) = xhat_p_(3) + radians(360.0f);

xhat_p_(3) = wrap_within_180(0.0, xhat_p_(3));
if(xhat_p_(3) > radians(180.0f) || xhat_p_(3) < radians(-180.0f))
{
RCLCPP_WARN(this->get_logger(), "Course estimate not wrapped from -pi to pi");
xhat_p_(3) = 0;
}

while(xhat_p_(6) > radians(180.0f)) xhat_p_(6) = xhat_p_(6) - radians(360.0f);
while(xhat_p_(6) < radians(-180.0f)) xhat_p_(6) = xhat_p_(6) + radians(360.0f);
xhat_p_(6) = wrap_within_180(0.0, xhat_p_(6));
if(xhat_p_(6) > radians(180.0f) || xhat_p_(6) < radians(-180.0f))
{
RCLCPP_WARN(this->get_logger(), "Psi estimate not wrapped from -pi to pi");
Expand All @@ -256,6 +257,7 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o


// measurement updates
// These calculate the Kalman gain and applies them to each state individually.
if (input.gps_new)
{

Expand Down Expand Up @@ -290,8 +292,7 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o
//wrap course measurement
float gps_course = fmodf(input.gps_course, radians(360.0f));

while (gps_course - xhat_p_(3) > radians(180.0f)) gps_course = gps_course - radians(360.0f);
while (gps_course - xhat_p_(3) < radians(-180.0f)) gps_course = gps_course + radians(360.0f);
xhat_p_(3) = wrap_within_180(xhat_p_(3), gps_course);
h_p_ = xhat_p_(3);

C_p_ = Eigen::VectorXf::Zero(7);
Expand Down Expand Up @@ -336,15 +337,15 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o
}

bool problem = false;
// int prob_index;
int prob_index;
for (int i = 0; i < 7; i++)
{
if (!std::isfinite(xhat_p_(i)))
{
if (!problem)
{
problem = true;
// prob_index = i;
prob_index = i;
}
switch (i)
{
Expand Down Expand Up @@ -378,7 +379,7 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o
}
if (problem)
{
// RCLCPP_WARN(this->get_logger(), "position estimator reinitialized due to non-finite state %d", prob_index); TODO come back and track down why pn is going infinite.
RCLCPP_WARN(this->get_logger(), "position estimator reinitialized due to non-finite state %d", prob_index);
}
if (xhat_p_(6) - xhat_p_(3) > radians(360.0f) || xhat_p_(6) - xhat_p_(3) < radians(-360.0f))
{
Expand All @@ -394,9 +395,6 @@ void estimator_example::estimate(const params_s &params, const input_s &input, o
float wehat = xhat_p_(5);
float psihat = xhat_p_(6);


// RCLCPP_INFO_STREAM(this->get_logger(), "chihat: " << chihat);

output.pn = pnhat;
output.pe = pehat;
output.h = hhat;
Expand Down