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realtimeroboticsgroup.org / RealtimeRoboticsGroup / test / 7227a8b7bee47beda92f7ee084f9abec40a59d6c / . / y2022 / localizer / localizer.cc
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#include "y2022/localizer/localizer.h"
#include "absl/flags/flag.h"
#include "aos/json_to_flatbuffer.h"
#include "frc971/control_loops/c2d.h"
#include "frc971/wpilib/imu_batch_generated.h"
#include "y2022/constants.h"
ABSL_FLAG(bool, ignore_accelerometer, false,
"If set, ignores the accelerometer readings.");
namespace frc971::controls {
namespace {
constexpr double kG = 9.80665;
static constexpr std::chrono::microseconds kNominalDt = ImuWatcher::kNominalDt;
// Field position of the target (the 2022 target is conveniently in the middle
// of the field....).
constexpr double kVisionTargetX = 0.0;
constexpr double kVisionTargetY = 0.0;
// Minimum confidence to require to use a target match.
constexpr double kMinTargetEstimateConfidence = 0.75;
template <int N>
Eigen::Matrix<double, N, 1> MakeState(std::vector<double> values) {
CHECK_EQ(static_cast<size_t>(N), values.size());
Eigen::Matrix<double, N, 1> vector;
for (int ii = 0; ii < N; ++ii) {
vector(ii, 0) = values[ii];
}
return vector;
}
} // namespace
ModelBasedLocalizer::ModelBasedLocalizer(
const control_loops::drivetrain::DrivetrainConfig<double> &dt_config)
: dt_config_(dt_config),
velocity_drivetrain_coefficients_(
dt_config.make_hybrid_drivetrain_velocity_loop()
.plant()
.coefficients()),
down_estimator_(dt_config) {
statistics_.rejection_counts.fill(0);
CHECK_EQ(branches_.capacity(),
static_cast<size_t>(std::chrono::seconds(1) / kNominalDt /
kBranchPeriod));
if (dt_config_.is_simulated) {
down_estimator_.assume_perfect_gravity();
}
A_continuous_accel_.setZero();
A_continuous_model_.setZero();
B_continuous_accel_.setZero();
B_continuous_model_.setZero();
A_continuous_accel_(kX, kVelocityX) = 1.0;
A_continuous_accel_(kY, kVelocityY) = 1.0;
const double diameter = 2.0 * dt_config_.robot_radius;
A_continuous_model_(kTheta, kLeftVelocity) = -1.0 / diameter;
A_continuous_model_(kTheta, kRightVelocity) = 1.0 / diameter;
A_continuous_model_(kLeftEncoder, kLeftVelocity) = 1.0;
A_continuous_model_(kRightEncoder, kRightVelocity) = 1.0;
const auto &vel_coefs = velocity_drivetrain_coefficients_;
A_continuous_model_(kLeftVelocity, kLeftVelocity) =
vel_coefs.A_continuous(0, 0);
A_continuous_model_(kLeftVelocity, kRightVelocity) =
vel_coefs.A_continuous(0, 1);
A_continuous_model_(kRightVelocity, kLeftVelocity) =
vel_coefs.A_continuous(1, 0);
A_continuous_model_(kRightVelocity, kRightVelocity) =
vel_coefs.A_continuous(1, 1);
A_continuous_model_(kLeftVelocity, kLeftVoltageError) =
1 * vel_coefs.B_continuous(0, 0);
A_continuous_model_(kLeftVelocity, kRightVoltageError) =
1 * vel_coefs.B_continuous(0, 1);
A_continuous_model_(kRightVelocity, kLeftVoltageError) =
1 * vel_coefs.B_continuous(1, 0);
A_continuous_model_(kRightVelocity, kRightVoltageError) =
1 * vel_coefs.B_continuous(1, 1);
B_continuous_model_.block<1, 2>(kLeftVelocity, kLeftVoltage) =
vel_coefs.B_continuous.row(0);
B_continuous_model_.block<1, 2>(kRightVelocity, kLeftVoltage) =
vel_coefs.B_continuous.row(1);
B_continuous_accel_(kVelocityX, kAccelX) = 1.0;
B_continuous_accel_(kVelocityY, kAccelY) = 1.0;
B_continuous_accel_(kTheta, kThetaRate) = 1.0;
Q_continuous_model_.setZero();
Q_continuous_model_.diagonal() << 1e-2, 1e-2, 1e-8, 1e-2, 1e-0, 1e-0, 1e-2,
1e-0, 1e-0;
Q_continuous_accel_.setZero();
Q_continuous_accel_.diagonal() << 1e-2, 1e-2, 1e-20, 1e-4, 1e-4;
P_model_ = Q_continuous_model_ * aos::time::DurationInSeconds(kNominalDt);
// We can precalculate the discretizations of the accel model because it is
// actually LTI.
DiscretizeQAFast(Q_continuous_accel_, A_continuous_accel_, kNominalDt,
&Q_discrete_accel_, &A_discrete_accel_);
P_accel_ = Q_discrete_accel_;
led_outputs_.fill(LedOutput::ON);
}
Eigen::Matrix<double, ModelBasedLocalizer::kNModelStates,
ModelBasedLocalizer::kNModelStates>
ModelBasedLocalizer::AModel(
const ModelBasedLocalizer::ModelState &state) const {
Eigen::Matrix<double, kNModelStates, kNModelStates> A = A_continuous_model_;
const double theta = state(kTheta);
const double stheta = std::sin(theta);
const double ctheta = std::cos(theta);
const double velocity = (state(kLeftVelocity) + state(kRightVelocity)) / 2.0;
A(kX, kTheta) = -stheta * velocity;
A(kX, kLeftVelocity) = ctheta / 2.0;
A(kX, kRightVelocity) = ctheta / 2.0;
A(kY, kTheta) = ctheta * velocity;
A(kY, kLeftVelocity) = stheta / 2.0;
A(kY, kRightVelocity) = stheta / 2.0;
return A;
}
Eigen::Matrix<double, ModelBasedLocalizer::kNAccelStates,
ModelBasedLocalizer::kNAccelStates>
ModelBasedLocalizer::AAccel() const {
return A_continuous_accel_;
}
ModelBasedLocalizer::ModelState ModelBasedLocalizer::DiffModel(
const ModelBasedLocalizer::ModelState &state,
const ModelBasedLocalizer::ModelInput &U) const {
ModelState x_dot = AModel(state) * state + B_continuous_model_ * U;
const double theta = state(kTheta);
const double stheta = std::sin(theta);
const double ctheta = std::cos(theta);
const double velocity = (state(kLeftVelocity) + state(kRightVelocity)) / 2.0;
x_dot(kX) = ctheta * velocity;
x_dot(kY) = stheta * velocity;
return x_dot;
}
ModelBasedLocalizer::AccelState ModelBasedLocalizer::DiffAccel(
const ModelBasedLocalizer::AccelState &state,
const ModelBasedLocalizer::AccelInput &U) const {
return AAccel() * state + B_continuous_accel_ * U;
}
ModelBasedLocalizer::ModelState ModelBasedLocalizer::UpdateModel(
const ModelBasedLocalizer::ModelState &model,
const ModelBasedLocalizer::ModelInput &input,
const aos::monotonic_clock::duration dt) const {
return control_loops::RungeKutta(
std::bind(&ModelBasedLocalizer::DiffModel, this, std::placeholders::_1,
input),
model, aos::time::DurationInSeconds(dt));
}
ModelBasedLocalizer::AccelState ModelBasedLocalizer::UpdateAccel(
const ModelBasedLocalizer::AccelState &accel,
const ModelBasedLocalizer::AccelInput &input,
const aos::monotonic_clock::duration dt) const {
return control_loops::RungeKutta(
std::bind(&ModelBasedLocalizer::DiffAccel, this, std::placeholders::_1,
input),
accel, aos::time::DurationInSeconds(dt));
}
ModelBasedLocalizer::AccelState ModelBasedLocalizer::AccelStateForModelState(
const ModelBasedLocalizer::ModelState &state) const {
const double robot_speed =
(state(kLeftVelocity) + state(kRightVelocity)) / 2.0;
const double lat_speed = (AModel(state) * state)(kTheta)*long_offset_;
const double velocity_x = std::cos(state(kTheta)) * robot_speed -
std::sin(state(kTheta)) * lat_speed;
const double velocity_y = std::sin(state(kTheta)) * robot_speed +
std::cos(state(kTheta)) * lat_speed;
return (AccelState() << state(0), state(1), state(2), velocity_x, velocity_y)
.finished();
}
ModelBasedLocalizer::ModelState ModelBasedLocalizer::ModelStateForAccelState(
const ModelBasedLocalizer::AccelState &state,
const Eigen::Vector2d &encoders, const double yaw_rate) const {
const double robot_speed = state(kVelocityX) * std::cos(state(kTheta)) +
state(kVelocityY) * std::sin(state(kTheta));
const double radius = dt_config_.robot_radius;
const double left_velocity = robot_speed - yaw_rate * radius;
const double right_velocity = robot_speed + yaw_rate * radius;
return (ModelState() << state(0), state(1), state(2), encoders(0),
left_velocity, 0.0, encoders(1), right_velocity, 0.0)
.finished();
}
double ModelBasedLocalizer::ModelDivergence(
const ModelBasedLocalizer::CombinedState &state,
const ModelBasedLocalizer::AccelInput &accel_inputs,
const Eigen::Vector2d &filtered_accel,
const ModelBasedLocalizer::ModelInput &model_inputs) {
// Convert the model state into the acceleration-based state-space and check
// the distance between the two (should really be a weighted norm, but all the
// numbers are on ~the same scale).
// TODO(james): Maybe weight lateral velocity divergence different than
// longitudinal? Seems like we tend to get false-positives currently when in
// sharp turns.
// TODO(james): For off-center gyros, maybe reduce noise when turning?
VLOG(2) << "divergence: "
<< (state.accel_state - AccelStateForModelState(state.model_state))
.transpose();
const AccelState diff_accel = DiffAccel(state.accel_state, accel_inputs);
const ModelState diff_model = DiffModel(state.model_state, model_inputs);
const double model_lng_velocity =
(state.model_state(kLeftVelocity) + state.model_state(kRightVelocity)) /
2.0;
const double model_lng_accel =
(diff_model(kLeftVelocity) + diff_model(kRightVelocity)) / 2.0 -
diff_model(kTheta) * diff_model(kTheta) * long_offset_;
const double model_lat_accel = diff_model(kTheta) * model_lng_velocity;
const Eigen::Vector2d robot_frame_accel(model_lng_accel, model_lat_accel);
const Eigen::Vector2d model_accel =
Eigen::AngleAxisd(state.model_state(kTheta), Eigen::Vector3d::UnitZ())
.toRotationMatrix()
.block<2, 2>(0, 0) *
robot_frame_accel;
const double accel_diff = (model_accel - filtered_accel).norm();
const double theta_rate_diff =
std::abs(diff_accel(kTheta) - diff_model(kTheta));
const Eigen::Vector2d accel_vel = state.accel_state.bottomRows<2>();
Eigen::Vector2d model_vel =
AccelStateForModelState(state.model_state).bottomRows<2>();
velocity_residual_ = (accel_vel - model_vel).norm() /
(1.0 + accel_vel.norm() + model_vel.norm());
theta_rate_residual_ = theta_rate_diff;
accel_residual_ = accel_diff / 4.0;
return velocity_residual_ + theta_rate_residual_ + accel_residual_;
}
void ModelBasedLocalizer::UpdateState(
CombinedState *state,
const Eigen::Matrix<double, kNModelStates, kNModelOutputs> &K,
const Eigen::Matrix<double, kNModelOutputs, 1> &Z,
const Eigen::Matrix<double, kNModelOutputs, kNModelStates> &H,
const AccelInput &accel_input, const ModelInput &model_input,
aos::monotonic_clock::duration dt) {
state->accel_state = UpdateAccel(state->accel_state, accel_input, dt);
if (down_estimator_.consecutive_still() > 500.0) {
state->accel_state(kVelocityX) *= 0.9;
state->accel_state(kVelocityY) *= 0.9;
}
state->model_state = UpdateModel(state->model_state, model_input, dt);
state->model_state += K * (Z - H * state->model_state);
}
void ModelBasedLocalizer::HandleImu(
aos::monotonic_clock::time_point t, const Eigen::Vector3d &gyro,
const Eigen::Vector3d &accel, const std::optional<Eigen::Vector2d> encoders,
const Eigen::Vector2d voltage) {
VLOG(2) << t;
if (t_ == aos::monotonic_clock::min_time) {
t_ = t;
}
if (t_ + 10 * kNominalDt < t) {
t_ = t;
++clock_resets_;
}
const aos::monotonic_clock::duration dt = t - t_;
t_ = t;
down_estimator_.Predict(gyro, accel, dt);
// TODO(james): Should we prefer this or use the down-estimator corrected
// version? Using the down estimator is more principled, but does create more
// opportunities for subtle biases.
const double yaw_rate = (dt_config_.imu_transform * gyro)(2);
const double diameter = 2.0 * dt_config_.robot_radius;
const Eigen::AngleAxis<double> orientation(
Eigen::AngleAxis<double>(xytheta()(kTheta), Eigen::Vector3d::UnitZ()) *
down_estimator_.X_hat());
last_orientation_ = orientation;
const Eigen::Vector3d absolute_accel =
orientation * dt_config_.imu_transform * kG * accel;
abs_accel_ = absolute_accel;
VLOG(2) << "abs accel " << absolute_accel.transpose();
VLOG(2) << "dt " << aos::time::DurationInSeconds(dt);
// Update all the branched states.
const AccelInput accel_input(absolute_accel.x(), absolute_accel.y(),
yaw_rate);
const ModelInput model_input(voltage);
const Eigen::Matrix<double, kNModelStates, kNModelStates> A_continuous =
AModel(current_state_.model_state);
Eigen::Matrix<double, kNModelStates, kNModelStates> A_discrete;
Eigen::Matrix<double, kNModelStates, kNModelStates> Q_discrete;
DiscretizeQAFast(Q_continuous_model_, A_continuous, dt, &Q_discrete,
&A_discrete);
P_model_ = A_discrete * P_model_ * A_discrete.transpose() + Q_discrete;
P_accel_ = A_discrete_accel_ * P_accel_ * A_discrete_accel_.transpose() +
Q_discrete_accel_;
Eigen::Matrix<double, kNModelOutputs, kNModelStates> H;
Eigen::Matrix<double, kNModelOutputs, kNModelOutputs> R;
{
H.setZero();
R.setZero();
H(0, kLeftEncoder) = 1.0;
H(1, kRightEncoder) = 1.0;
H(2, kRightVelocity) = 1.0 / diameter;
H(2, kLeftVelocity) = -1.0 / diameter;
R.diagonal() << 1e-9, 1e-9, 1e-13;
}
const Eigen::Matrix<double, kNModelOutputs, 1> Z =
encoders.has_value()
? Eigen::Vector3d(encoders.value()(0), encoders.value()(1), yaw_rate)
: Eigen::Vector3d(current_state_.model_state(kLeftEncoder),
current_state_.model_state(kRightEncoder),
yaw_rate);
if (branches_.empty()) {
VLOG(2) << "Initializing";
current_state_.model_state(kLeftEncoder) = Z(0);
current_state_.model_state(kRightEncoder) = Z(1);
current_state_.branch_time = t;
branches_.Push(current_state_);
}
const Eigen::Matrix<double, kNModelStates, kNModelOutputs> K =
P_model_ * H.transpose() * (H * P_model_ * H.transpose() + R).inverse();
P_model_ = (Eigen::Matrix<double, kNModelStates, kNModelStates>::Identity() -
K * H) *
P_model_;
VLOG(2) << "K\n" << K;
VLOG(2) << "Z\n" << Z.transpose();
for (CombinedState &state : branches_) {
UpdateState(&state, K, Z, H, accel_input, model_input, dt);
}
UpdateState(&current_state_, K, Z, H, accel_input, model_input, dt);
VLOG(2) << "oildest accel " << branches_[0].accel_state.transpose();
VLOG(2) << "oildest accel diff "
<< DiffAccel(branches_[0].accel_state, accel_input).transpose();
VLOG(2) << "oildest model " << branches_[0].model_state.transpose();
// Determine whether to switch modes--if we are currently in model-based mode,
// swap to accel-based if the two states have divergeed meaningfully in the
// oldest branch. If we are currently in accel-based, then swap back to model
// if the oldest model branch matches has matched the
filtered_residual_accel_ +=
0.01 * (accel_input.topRows<2>() - filtered_residual_accel_);
const double model_divergence =
branches_.full() ? ModelDivergence(branches_[0], accel_input,
filtered_residual_accel_, model_input)
: 0.0;
filtered_residual_ +=
(1.0 - std::exp(-aos::time::DurationInSeconds(kNominalDt) / 0.0095)) *
(model_divergence - filtered_residual_);
// TODO(james): Tune this more. Currently set to generally trust the model,
// perhaps a bit too much.
// When the residual exceeds the accel threshold, we start using the inertials
// alone; when it drops back below the model threshold, we go back to being
// model-based.
constexpr double kUseAccelThreshold = 2.0;
constexpr double kUseModelThreshold = 0.5;
constexpr size_t kShareStates = kNModelStates;
static_assert(kUseModelThreshold < kUseAccelThreshold);
if (using_model_) {
if (!absl::GetFlag(FLAGS_ignore_accelerometer) &&
filtered_residual_ > kUseAccelThreshold) {
hysteresis_count_++;
} else {
hysteresis_count_ = 0;
}
if (hysteresis_count_ > 0) {
using_model_ = false;
// Grab the accel-based state from back when we started diverging.
// TODO(james): This creates a problematic selection bias, because
// we will tend to bias towards deliberately out-of-tune measurements.
current_state_.accel_state = branches_[0].accel_state;
current_state_.model_state = branches_[0].model_state;
current_state_.model_state = ModelStateForAccelState(
current_state_.accel_state, Z.topRows<2>(), yaw_rate);
} else {
VLOG(2) << "Normal branching";
current_state_.accel_state =
AccelStateForModelState(current_state_.model_state);
current_state_.branch_time = t;
}
hysteresis_count_ = 0;
} else {
if (filtered_residual_ < kUseModelThreshold) {
hysteresis_count_++;
} else {
hysteresis_count_ = 0;
}
if (hysteresis_count_ > 100) {
using_model_ = true;
// Grab the model-based state from back when we stopped diverging.
current_state_.model_state.topRows<kShareStates>() =
ModelStateForAccelState(branches_[0].accel_state, Z.topRows<2>(),
yaw_rate)
.topRows<kShareStates>();
current_state_.accel_state =
AccelStateForModelState(current_state_.model_state);
} else {
// TODO(james): Why was I leaving the encoders/wheel velocities in place?
current_state_.model_state = ModelStateForAccelState(
current_state_.accel_state, Z.topRows<2>(), yaw_rate);
current_state_.branch_time = t;
}
}
// Generate a new branch, with the accel state reset based on the model-based
// state (really, just getting rid of the lateral velocity).
// By resetting the accel state in the new branch, this tries to minimize the
// odds of runaway lateral velocities. This doesn't help with runaway
// longitudinal velocities, however.
CombinedState new_branch = current_state_;
new_branch.accel_state = AccelStateForModelState(new_branch.model_state);
new_branch.accumulated_divergence = 0.0;
++branch_counter_;
if (branch_counter_ % kBranchPeriod == 0) {
branches_.Push(new_branch);
old_positions_.Push(OldPosition{t, xytheta(), latest_turret_position_,
latest_turret_velocity_});
branch_counter_ = 0;
}
last_residual_ = model_divergence;
VLOG(2) << "Using " << (using_model_ ? "model" : "accel");
VLOG(2) << "Residual " << last_residual_;
VLOG(2) << "Filtered Residual " << filtered_residual_;
VLOG(2) << "buffer size " << branches_.size();
VLOG(2) << "Model state " << current_state_.model_state.transpose();
VLOG(2) << "Accel state " << current_state_.accel_state.transpose();
VLOG(2) << "Accel state for model "
<< AccelStateForModelState(current_state_.model_state).transpose();
VLOG(2) << "Input acce " << accel.transpose();
VLOG(2) << "Input gyro " << gyro.transpose();
VLOG(2) << "Input voltage " << voltage.transpose();
VLOG(2) << "Input encoder " << Z.topRows<2>().transpose();
VLOG(2) << "yaw rate " << yaw_rate;
CHECK(std::isfinite(last_residual_));
}
const ModelBasedLocalizer::OldPosition ModelBasedLocalizer::GetStateForTime(
aos::monotonic_clock::time_point time) {
if (old_positions_.empty()) {
return OldPosition{};
}
aos::monotonic_clock::duration lowest_time_error =
aos::monotonic_clock::duration::max();
const OldPosition *best_match = nullptr;
for (const OldPosition &sample : old_positions_) {
const aos::monotonic_clock::duration time_error =
std::chrono::abs(sample.sample_time - time);
if (time_error < lowest_time_error) {
lowest_time_error = time_error;
best_match = &sample;
}
}
return *best_match;
}
namespace {
// Node names of the pis to listen for cameras from.
constexpr std::array<std::string_view, ModelBasedLocalizer::kNumPis> kPisToUse{
"pi1", "pi2", "pi3", "pi4"};
} // namespace
const Eigen::Matrix<double, 4, 4> ModelBasedLocalizer::CameraTransform(
const OldPosition &state,
const frc971::vision::calibration::CameraCalibration *calibration,
std::optional<RejectionReason> *rejection_reason) const {
CHECK(rejection_reason != nullptr);
CHECK(calibration != nullptr);
// Per the CameraCalibration specification, we can actually determine whether
// the camera is the turret camera just from the presence of the
// turret_extrinsics member.
const bool is_turret = calibration->has_turret_extrinsics();
// Ignore readings when the turret is spinning too fast, on the assumption
// that the odds of screwing up the time compensation are higher.
// Note that the current number here is chosen pretty arbitrarily--1 rad / sec
// seems reasonable, but may be unnecessarily low or high.
constexpr double kMaxTurretVelocity = 1.0;
if (is_turret && std::abs(state.turret_velocity) > kMaxTurretVelocity &&
!rejection_reason->has_value()) {
*rejection_reason = RejectionReason::TURRET_TOO_FAST;
}
CHECK(calibration->has_fixed_extrinsics());
const Eigen::Matrix<double, 4, 4> fixed_extrinsics =
control_loops::drivetrain::FlatbufferToTransformationMatrix(
*calibration->fixed_extrinsics());
// Calculate the pose of the camera relative to the robot origin.
Eigen::Matrix<double, 4, 4> H_robot_camera = fixed_extrinsics;
if (is_turret) {
H_robot_camera =
H_robot_camera *
frc971::control_loops::TransformationMatrixForYaw<double>(
state.turret_position) *
control_loops::drivetrain::FlatbufferToTransformationMatrix(
*calibration->turret_extrinsics());
}
return H_robot_camera;
}
const std::optional<Eigen::Vector2d>
ModelBasedLocalizer::CameraMeasuredRobotPosition(
const OldPosition &state, const y2022::vision::TargetEstimate *target,
std::optional<RejectionReason> *rejection_reason,
Eigen::Matrix<double, 4, 4> *H_field_camera_measured) const {
if (!target->has_camera_calibration()) {
*rejection_reason = RejectionReason::NO_CALIBRATION;
return std::nullopt;
}
const Eigen::Matrix<double, 4, 4> H_robot_camera =
CameraTransform(state, target->camera_calibration(), rejection_reason);
const control_loops::Pose robot_pose(
{state.xytheta(0), state.xytheta(1), 0.0}, state.xytheta(2));
const Eigen::Matrix<double, 4, 4> H_field_robot =
robot_pose.AsTransformationMatrix();
// Current estimated pose of the camera in the global frame.
// Note that this is all really just an elaborate way of extracting the
// current estimated camera yaw, and nothing else.
const Eigen::Matrix<double, 4, 4> H_field_camera =
H_field_robot * H_robot_camera;
// Grab the implied yaw of the camera (the +Z axis is coming out of the front
// of the cameras).
const Eigen::Vector3d rotated_camera_z =
H_field_camera.block<3, 3>(0, 0) * Eigen::Vector3d(0, 0, 1);
const double camera_yaw =
std::atan2(rotated_camera_z.y(), rotated_camera_z.x());
// All right, now we need to use the heading and distance from the
// TargetEstimate, plus the yaw embedded in the camera_pose, to determine what
// the implied X/Y position of the robot is. To do this, we calculate the
// heading/distance from the target to the robot. The distance is easy, since
// that's the same as the distance from the robot to the target. The heading
// isn't too hard, but is obnoxious to think about, since the heading from the
// target to the robot is distinct from the heading from the robot to the
// target.
// Just to walk through examples to confirm that the below calculation is
// correct:
// * If yaw = 0, and angle_to_target = 0, we are at 180 deg relative to the
// target.
// * If yaw = 90 deg, and angle_to_target = 0, we are at -90 deg relative to
// the target.
// * If yaw = 0, and angle_to_target = 90 deg, we are at -90 deg relative to
// the target.
const double heading_from_target =
aos::math::NormalizeAngle(M_PI + camera_yaw + target->angle_to_target());
const double distance_from_target = target->distance();
// Extract the implied camera position on the field.
*H_field_camera_measured = H_field_camera;
// TODO(james): Are we going to need to evict the roll/pitch components of the
// camera extrinsics this year as well?
(*H_field_camera_measured)(0, 3) =
distance_from_target * std::cos(heading_from_target) + kVisionTargetX;
(*H_field_camera_measured)(1, 3) =
distance_from_target * std::sin(heading_from_target) + kVisionTargetY;
const Eigen::Matrix<double, 4, 4> H_field_robot_measured =
*H_field_camera_measured * H_robot_camera.inverse();
return H_field_robot_measured.block<2, 1>(0, 3);
}
void ModelBasedLocalizer::HandleImageMatch(
aos::monotonic_clock::time_point sample_time,
const y2022::vision::TargetEstimate *target, int camera_index) {
std::optional<RejectionReason> rejection_reason;
if (target->confidence() < kMinTargetEstimateConfidence) {
rejection_reason = RejectionReason::LOW_CONFIDENCE;
TallyRejection(rejection_reason.value());
return;
}
const OldPosition &state = GetStateForTime(sample_time);
Eigen::Matrix<double, 4, 4> H_field_camera_measured;
const std::optional<Eigen::Vector2d> measured_robot_position =
CameraMeasuredRobotPosition(state, target, &rejection_reason,
&H_field_camera_measured);
// Technically, rejection_reason should always be set if
// measured_robot_position is nullopt, but in the future we may have more
// recoverable rejection reasons that we wish to allow to propagate further
// into the process.
if (!measured_robot_position || rejection_reason.has_value()) {
CHECK(rejection_reason.has_value());
TallyRejection(rejection_reason.value());
return;
}
// Next, go through and do the actual Kalman corrections for the x/y
// measurement, for both the accel state and the model-based state.
const Eigen::Matrix<double, kNModelStates, kNModelStates> A_continuous_model =
AModel(current_state_.model_state);
Eigen::Matrix<double, kNModelStates, kNModelStates> A_discrete_model;
Eigen::Matrix<double, kNModelStates, kNModelStates> Q_discrete_model;
DiscretizeQAFast(Q_continuous_model_, A_continuous_model, kNominalDt,
&Q_discrete_model, &A_discrete_model);
Eigen::Matrix<double, 2, kNModelStates> H_model;
H_model.setZero();
Eigen::Matrix<double, 2, kNAccelStates> H_accel;
H_accel.setZero();
Eigen::Matrix<double, 2, 2> R;
R.setZero();
H_model(0, kX) = 1.0;
H_model(1, kY) = 1.0;
H_accel(0, kX) = 1.0;
H_accel(1, kY) = 1.0;
if (aggressive_corrections_) {
R.diagonal() << 1e-2, 1e-2;
} else {
R.diagonal() << 1e-0, 1e-0;
}
const Eigen::Matrix<double, kNModelStates, 2> K_model =
P_model_ * H_model.transpose() *
(H_model * P_model_ * H_model.transpose() + R).inverse();
const Eigen::Matrix<double, kNAccelStates, 2> K_accel =
P_accel_ * H_accel.transpose() *
(H_accel * P_accel_ * H_accel.transpose() + R).inverse();
P_model_ = (Eigen::Matrix<double, kNModelStates, kNModelStates>::Identity() -
K_model * H_model) *
P_model_;
P_accel_ = (Eigen::Matrix<double, kNAccelStates, kNAccelStates>::Identity() -
K_accel * H_accel) *
P_accel_;
// And now we have to correct *everything* on all the branches:
for (CombinedState &state : branches_) {
state.model_state += K_model * (measured_robot_position.value() -
H_model * state.model_state);
state.accel_state += K_accel * (measured_robot_position.value() -
H_accel * state.accel_state);
}
current_state_.model_state +=
K_model *
(measured_robot_position.value() - H_model * current_state_.model_state);
current_state_.accel_state +=
K_accel *
(measured_robot_position.value() - H_accel * current_state_.accel_state);
statistics_.total_accepted++;
statistics_.total_candidates++;
const Eigen::Vector3d camera_z_in_field =
H_field_camera_measured.block<3, 3>(0, 0) * Eigen::Vector3d::UnitZ();
const double camera_yaw =
std::atan2(camera_z_in_field.y(), camera_z_in_field.x());
// TODO(milind): actually control this
led_outputs_[camera_index] = LedOutput::ON;
TargetEstimateDebugT debug;
debug.camera = static_cast<uint8_t>(camera_index);
debug.camera_x = H_field_camera_measured(0, 3);
debug.camera_y = H_field_camera_measured(1, 3);
debug.camera_theta = camera_yaw;
debug.implied_robot_x = measured_robot_position.value().x();
debug.implied_robot_y = measured_robot_position.value().y();
debug.implied_robot_theta = xytheta()(2);
debug.implied_turret_goal =
aos::math::NormalizeAngle(camera_yaw + target->angle_to_target());
debug.accepted = true;
debug.image_age_sec = aos::time::DurationInSeconds(t_ - sample_time);
CHECK_LT(image_debugs_.size(), kDebugBufferSize);
image_debugs_.push_back(debug);
}
void ModelBasedLocalizer::HandleTurret(
aos::monotonic_clock::time_point sample_time, double turret_position,
double turret_velocity) {
last_turret_update_ = sample_time;
latest_turret_position_ = turret_position;
latest_turret_velocity_ = turret_velocity;
}
void ModelBasedLocalizer::HandleReset(aos::monotonic_clock::time_point now,
const Eigen::Vector3d &xytheta) {
branches_.Reset();
t_ = now;
using_model_ = true;
current_state_.model_state << xytheta(0), xytheta(1), xytheta(2),
current_state_.model_state(kLeftEncoder), 0.0, 0.0,
current_state_.model_state(kRightEncoder), 0.0, 0.0;
current_state_.accel_state =
AccelStateForModelState(current_state_.model_state);
last_residual_ = 0.0;
filtered_residual_ = 0.0;
filtered_residual_accel_.setZero();
abs_accel_.setZero();
}
flatbuffers::Offset<AccelBasedState> ModelBasedLocalizer::BuildAccelState(
flatbuffers::FlatBufferBuilder *fbb, const AccelState &state) {
AccelBasedState::Builder accel_state_builder(*fbb);
accel_state_builder.add_x(state(kX));
accel_state_builder.add_y(state(kY));
accel_state_builder.add_theta(state(kTheta));
accel_state_builder.add_velocity_x(state(kVelocityX));
accel_state_builder.add_velocity_y(state(kVelocityY));
return accel_state_builder.Finish();
}
flatbuffers::Offset<ModelBasedState> ModelBasedLocalizer::BuildModelState(
flatbuffers::FlatBufferBuilder *fbb, const ModelState &state) {
ModelBasedState::Builder model_state_builder(*fbb);
model_state_builder.add_x(state(kX));
model_state_builder.add_y(state(kY));
model_state_builder.add_theta(state(kTheta));
model_state_builder.add_left_encoder(state(kLeftEncoder));
model_state_builder.add_left_velocity(state(kLeftVelocity));
model_state_builder.add_left_voltage_error(state(kLeftVoltageError));
model_state_builder.add_right_encoder(state(kRightEncoder));
model_state_builder.add_right_velocity(state(kRightVelocity));
model_state_builder.add_right_voltage_error(state(kRightVoltageError));
return model_state_builder.Finish();
}
flatbuffers::Offset<CumulativeStatistics>
ModelBasedLocalizer::PopulateStatistics(flatbuffers::FlatBufferBuilder *fbb) {
const auto rejections_offset = fbb->CreateVector(
statistics_.rejection_counts.data(), statistics_.rejection_counts.size());
CumulativeStatistics::Builder stats_builder(*fbb);
stats_builder.add_total_accepted(statistics_.total_accepted);
stats_builder.add_total_candidates(statistics_.total_candidates);
stats_builder.add_rejection_reason_count(rejections_offset);
return stats_builder.Finish();
}
flatbuffers::Offset<ModelBasedStatus> ModelBasedLocalizer::PopulateStatus(
flatbuffers::FlatBufferBuilder *fbb) {
const flatbuffers::Offset<CumulativeStatistics> stats_offset =
PopulateStatistics(fbb);
const flatbuffers::Offset<control_loops::drivetrain::DownEstimatorState>
down_estimator_offset = down_estimator_.PopulateStatus(fbb, t_);
const CombinedState &state = current_state_;
const flatbuffers::Offset<ModelBasedState> model_state_offset =
BuildModelState(fbb, state.model_state);
const flatbuffers::Offset<AccelBasedState> accel_state_offset =
BuildAccelState(fbb, state.accel_state);
const flatbuffers::Offset<AccelBasedState> oldest_accel_state_offset =
branches_.empty() ? flatbuffers::Offset<AccelBasedState>()
: BuildAccelState(fbb, branches_[0].accel_state);
const flatbuffers::Offset<ModelBasedState> oldest_model_state_offset =
branches_.empty() ? flatbuffers::Offset<ModelBasedState>()
: BuildModelState(fbb, branches_[0].model_state);
ModelBasedStatus::Builder builder(*fbb);
builder.add_accel_state(accel_state_offset);
builder.add_oldest_accel_state(oldest_accel_state_offset);
builder.add_oldest_model_state(oldest_model_state_offset);
builder.add_model_state(model_state_offset);
builder.add_using_model(using_model_);
builder.add_residual(last_residual_);
builder.add_filtered_residual(filtered_residual_);
builder.add_velocity_residual(velocity_residual_);
builder.add_accel_residual(accel_residual_);
builder.add_theta_rate_residual(theta_rate_residual_);
builder.add_down_estimator(down_estimator_offset);
builder.add_x(xytheta()(0));
builder.add_y(xytheta()(1));
builder.add_theta(xytheta()(2));
builder.add_implied_accel_x(abs_accel_(0));
builder.add_implied_accel_y(abs_accel_(1));
builder.add_implied_accel_z(abs_accel_(2));
builder.add_clock_resets(clock_resets_);
builder.add_statistics(stats_offset);
return builder.Finish();
}
flatbuffers::Offset<LocalizerVisualization>
ModelBasedLocalizer::PopulateVisualization(
flatbuffers::FlatBufferBuilder *fbb) {
const flatbuffers::Offset<CumulativeStatistics> stats_offset =
PopulateStatistics(fbb);
aos::SizedArray<flatbuffers::Offset<TargetEstimateDebug>, kDebugBufferSize>
debug_offsets;
for (const TargetEstimateDebugT &debug : image_debugs_) {
debug_offsets.push_back(PackTargetEstimateDebug(debug, fbb));
}
image_debugs_.clear();
const flatbuffers::Offset<
flatbuffers::Vector<flatbuffers::Offset<TargetEstimateDebug>>>
debug_offset =
fbb->CreateVector(debug_offsets.data(), debug_offsets.size());
LocalizerVisualization::Builder builder(*fbb);
builder.add_statistics(stats_offset);
builder.add_targets(debug_offset);
return builder.Finish();
}
void ModelBasedLocalizer::TallyRejection(const RejectionReason reason) {
statistics_.total_candidates++;
statistics_.rejection_counts[static_cast<size_t>(reason)]++;
TargetEstimateDebugT debug;
debug.accepted = false;
debug.rejection_reason = reason;
CHECK_LT(image_debugs_.size(), kDebugBufferSize);
image_debugs_.push_back(debug);
}
flatbuffers::Offset<TargetEstimateDebug>
ModelBasedLocalizer::PackTargetEstimateDebug(
const TargetEstimateDebugT &debug, flatbuffers::FlatBufferBuilder *fbb) {
if (!debug.accepted) {
TargetEstimateDebug::Builder builder(*fbb);
builder.add_accepted(debug.accepted);
builder.add_rejection_reason(debug.rejection_reason);
return builder.Finish();
} else {
flatbuffers::Offset<TargetEstimateDebug> offset =
TargetEstimateDebug::Pack(*fbb, &debug);
flatbuffers::GetMutableTemporaryPointer(*fbb, offset)
->clear_rejection_reason();
return offset;
}
}
EventLoopLocalizer::EventLoopLocalizer(
aos::EventLoop *event_loop,
const control_loops::drivetrain::DrivetrainConfig<double> &dt_config)
: event_loop_(event_loop),
model_based_(dt_config),
status_sender_(event_loop_->MakeSender<LocalizerStatus>("/localizer")),
output_sender_(event_loop_->MakeSender<LocalizerOutput>("/localizer")),
visualization_sender_(
event_loop_->MakeSender<LocalizerVisualization>("/localizer")),
superstructure_fetcher_(
event_loop_
->MakeFetcher<y2022::control_loops::superstructure::Status>(
"/superstructure")),
imu_watcher_(event_loop, dt_config,
y2022::constants::Values::DrivetrainEncoderToMeters(1),
[this](aos::monotonic_clock::time_point sample_time_pico,
aos::monotonic_clock::time_point sample_time_pi,
std::optional<Eigen::Vector2d> encoders,
Eigen::Vector3d gyro, Eigen::Vector3d accel) {
HandleImu(sample_time_pico, sample_time_pi, encoders, gyro,
accel);
}),
utils_(event_loop) {
event_loop->SetRuntimeRealtimePriority(10);
event_loop_->MakeWatcher(
"/drivetrain",
[this](
const frc971::control_loops::drivetrain::LocalizerControl &control) {
const double theta = control.keep_current_theta()
? model_based_.xytheta()(2)
: control.theta();
model_based_.HandleReset(event_loop_->monotonic_now(),
{control.x(), control.y(), theta});
});
aos::TimerHandler *superstructure_timer = event_loop_->AddTimer([this]() {
if (superstructure_fetcher_.Fetch()) {
const y2022::control_loops::superstructure::Status &status =
*superstructure_fetcher_.get();
if (!status.has_turret()) {
return;
}
CHECK(status.has_turret());
model_based_.HandleTurret(
superstructure_fetcher_.context().monotonic_event_time,
status.turret()->position(), status.turret()->velocity());
}
});
event_loop_->OnRun([this, superstructure_timer]() {
superstructure_timer->Schedule(event_loop_->monotonic_now(),
std::chrono::milliseconds(20));
});
for (size_t camera_index = 0; camera_index < kPisToUse.size();
++camera_index) {
CHECK_LT(camera_index, target_estimate_fetchers_.size());
target_estimate_fetchers_[camera_index] =
event_loop_->MakeFetcher<y2022::vision::TargetEstimate>(
absl::StrCat("/", kPisToUse[camera_index], "/camera"));
}
aos::TimerHandler *estimate_timer = event_loop_->AddTimer([this]() {
const bool maybe_in_auto = utils_.MaybeInAutonomous();
model_based_.set_use_aggressive_image_corrections(!maybe_in_auto);
for (size_t camera_index = 0; camera_index < kPisToUse.size();
++camera_index) {
if (model_based_.NumQueuedImageDebugs() ==
ModelBasedLocalizer::kDebugBufferSize ||
(last_visualization_send_ + kMinVisualizationPeriod <
event_loop_->monotonic_now())) {
auto builder = visualization_sender_.MakeBuilder();
visualization_sender_.CheckOk(
builder.Send(model_based_.PopulateVisualization(builder.fbb())));
}
if (target_estimate_fetchers_[camera_index].Fetch()) {
const std::optional<aos::monotonic_clock::duration> monotonic_offset =
utils_.ClockOffset(kPisToUse[camera_index]);
if (!monotonic_offset.has_value()) {
model_based_.TallyRejection(
RejectionReason::MESSAGE_BRIDGE_DISCONNECTED);
continue;
}
// TODO(james): Get timestamp from message contents.
aos::monotonic_clock::time_point capture_time(
target_estimate_fetchers_[camera_index]
.context()
.monotonic_remote_time -
monotonic_offset.value());
if (capture_time > target_estimate_fetchers_[camera_index]
.context()
.monotonic_event_time) {
model_based_.TallyRejection(RejectionReason::IMAGE_FROM_FUTURE);
continue;
}
capture_time -= imu_watcher_.pico_offset_error();
model_based_.HandleImageMatch(
capture_time, target_estimate_fetchers_[camera_index].get(),
camera_index);
}
}
});
event_loop_->OnRun([this, estimate_timer]() {
estimate_timer->Schedule(event_loop_->monotonic_now(),
std::chrono::milliseconds(100));
});
}
void EventLoopLocalizer::HandleImu(
aos::monotonic_clock::time_point sample_time_pico,
aos::monotonic_clock::time_point sample_time_pi,
std::optional<Eigen::Vector2d> encoders, Eigen::Vector3d gyro,
Eigen::Vector3d accel) {
model_based_.HandleImu(
sample_time_pico, gyro, accel, encoders,
utils_.VoltageOrZero(event_loop_->context().monotonic_event_time));
{
auto builder = status_sender_.MakeBuilder();
const flatbuffers::Offset<ModelBasedStatus> model_based_status =
model_based_.PopulateStatus(builder.fbb());
const flatbuffers::Offset<control_loops::drivetrain::ImuZeroerState>
zeroer_status = imu_watcher_.zeroer().PopulateStatus(builder.fbb());
const flatbuffers::Offset<ImuFailures> imu_failures =
imu_watcher_.PopulateImuFailures(builder.fbb());
LocalizerStatus::Builder status_builder =
builder.MakeBuilder<LocalizerStatus>();
status_builder.add_model_based(model_based_status);
status_builder.add_zeroed(imu_watcher_.zeroer().Zeroed());
status_builder.add_faulted_zero(imu_watcher_.zeroer().Faulted());
status_builder.add_zeroing(zeroer_status);
status_builder.add_imu_failures(imu_failures);
if (encoders.has_value()) {
status_builder.add_left_encoder(encoders.value()(0));
status_builder.add_right_encoder(encoders.value()(1));
}
if (imu_watcher_.pico_offset().has_value()) {
status_builder.add_pico_offset_ns(
imu_watcher_.pico_offset().value().count());
status_builder.add_pico_offset_error_ns(
imu_watcher_.pico_offset_error().count());
}
builder.CheckOk(builder.Send(status_builder.Finish()));
}
if (last_output_send_ + std::chrono::milliseconds(5) <
event_loop_->context().monotonic_event_time) {
auto builder = output_sender_.MakeBuilder();
const auto led_outputs_offset = builder.fbb()->CreateVector(
model_based_.led_outputs().data(), model_based_.led_outputs().size());
LocalizerOutput::Builder output_builder =
builder.MakeBuilder<LocalizerOutput>();
output_builder.add_monotonic_timestamp_ns(
std::chrono::duration_cast<std::chrono::nanoseconds>(
sample_time_pi.time_since_epoch())
.count());
output_builder.add_x(model_based_.xytheta()(0));
output_builder.add_y(model_based_.xytheta()(1));
output_builder.add_theta(model_based_.xytheta()(2));
output_builder.add_zeroed(imu_watcher_.zeroer().Zeroed());
output_builder.add_image_accepted_count(model_based_.total_accepted());
const Eigen::Quaterniond &orientation = model_based_.orientation();
Quaternion quaternion;
quaternion.mutate_x(orientation.x());
quaternion.mutate_y(orientation.y());
quaternion.mutate_z(orientation.z());
quaternion.mutate_w(orientation.w());
output_builder.add_orientation(&quaternion);
output_builder.add_led_outputs(led_outputs_offset);
builder.CheckOk(builder.Send(output_builder.Finish()));
last_output_send_ = event_loop_->monotonic_now();
}
}
} // namespace frc971::controls