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[Estimation][VO/VIO] refactor the process of KF based estimation with visual odometry #601

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Apr 12, 2024
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[Estimation][VO/VIO] refactor the process of KF based estimation with visual odometry #601

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6db4245
[Estimation][VO][WIP] refactor the process for velocity related to th…
tongtybj Jun 4, 2023
756199b
[Estimation][VIO] refactor the calculation of the transfrom from the …
tongtybj Feb 16, 2024
5688e4f
[Estimation][VIO] add static tf from the world frame to the vo origin…
tongtybj Feb 16, 2024
283a137
[Estimation][VIO] fix bug: initialize prev_timestamp
tongtybj Feb 17, 2024
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7 changes: 7 additions & 0 deletions aerial_robot_estimation/include/aerial_robot_estimation/sensor/vo.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,14 @@

#include <aerial_robot_estimation/sensor/base_plugin.h>
#include <geometry_msgs/Vector3Stamped.h>
#include <geometry_msgs/TransformStamped.h>
#include <kalman_filter/kf_pos_vel_acc_plugin.h>
#include <nav_msgs/Odometry.h>
#include <sensor_msgs/JointState.h>
#include <spinal/ServoControlCmd.h>
#include <std_msgs/Empty.h>
#include <tf2_ros/static_transform_broadcaster.h>


namespace sensor_plugin
{
Expand Down Expand Up @@ -85,11 +88,13 @@ namespace sensor_plugin
int fusion_mode_;
bool vio_mode_; // visual + inertial mode
bool z_vel_mode_;
bool local_vel_mode_;
bool outdoor_no_vel_time_sync_; // very special flag for stereo cam such as zed mini, which has tricky behavier in outdoor mode
/* heuristic sepecial flag for fusion */
bool outdoor_;
bool z_no_delay_;


/* servo */
std::string joint_name_;
bool servo_auto_change_flag_;
Expand All @@ -109,6 +114,8 @@ namespace sensor_plugin
double reference_timestamp_;
aerial_robot_msgs::States vo_state_;

tf2_ros::StaticTransformBroadcaster static_broadcaster_; // publish the transfrom between the work and vo frame

void rosParamInit();
void servoControl(const ros::TimerEvent & e);
void estimateProcess();
Expand Down
67 changes: 45 additions & 22 deletions aerial_robot_estimation/src/sensor/vo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,7 @@ namespace sensor_plugin
if(time_sync_) queuse_size = 10;
vo_sub_ = nh_.subscribe(topic_name, queuse_size, &VisualOdometry::voCallback, this);


/* servo control timer */
if(variable_sensor_tf_flag_)
{
Expand All @@ -92,6 +93,8 @@ namespace sensor_plugin

servo_control_timer_ = indexed_nhp_.createTimer(ros::Duration(servo_control_rate_), &VisualOdometry::servoControl,this); // 10 Hz
}

prev_timestamp_ = 0;
}

void VisualOdometry::voCallback(const nav_msgs::Odometry::ConstPtr & vo_msg)
Expand Down Expand Up @@ -238,33 +241,43 @@ namespace sensor_plugin
}
}

/* step1: set the init offset from world to the baselink of UAV from egomotion estimation (e.g. yaw) */
/** ^{w}H_{b} **/
world_offset_tf_.setRotation(tf::createQuaternionFromYaw(estimator_->getState(State::YAW_BASE, aerial_robot_estimation::EGOMOTION_ESTIMATE)[0]));
/** step1: ^{w}H_{b'}, b': level frame of b **/
tf::Transform w_bdash_f(tf::createQuaternionFromYaw(estimator_->getState(State::YAW_BASE, aerial_robot_estimation::EGOMOTION_ESTIMATE)[0]));

tf::Vector3 world_offset_pos = estimator_->getPos(Frame::BASELINK, aerial_robot_estimation::EGOMOTION_ESTIMATE);
tf::Vector3 baselink_pos = estimator_->getPos(Frame::BASELINK, aerial_robot_estimation::EGOMOTION_ESTIMATE);
if(estimator_->getStateStatus(State::X_BASE, aerial_robot_estimation::EGOMOTION_ESTIMATE))
world_offset_tf_.getOrigin().setX(world_offset_pos.x());
w_bdash_f.getOrigin().setX(baselink_pos.x());
if(estimator_->getStateStatus(State::Y_BASE, aerial_robot_estimation::EGOMOTION_ESTIMATE))
world_offset_tf_.getOrigin().setY(world_offset_pos.y());
w_bdash_f.getOrigin().setY(baselink_pos.y());
if(estimator_->getStateStatus(State::Z_BASE, aerial_robot_estimation::EGOMOTION_ESTIMATE))
world_offset_tf_.getOrigin().setZ(world_offset_pos.z());
w_bdash_f.getOrigin().setZ(baselink_pos.z());

/* set the init offset from world to the baselink of UAV if we know the ground truth */
/* set the offset if we know the ground truth */
if(estimator_->getStateStatus(State::YAW_BASE, aerial_robot_estimation::GROUND_TRUTH))
{
world_offset_tf_.setOrigin(estimator_->getPos(Frame::BASELINK, aerial_robot_estimation::GROUND_TRUTH));
world_offset_tf_.setRotation(tf::createQuaternionFromYaw(estimator_->getState(State::YAW_BASE, aerial_robot_estimation::GROUND_TRUTH)[0]));

double y, p, r; world_offset_tf_.getBasis().getRPY(r, p, y);
w_bdash_f.setOrigin(estimator_->getPos(Frame::BASELINK, aerial_robot_estimation::GROUND_TRUTH));
w_bdash_f.setRotation(tf::createQuaternionFromYaw(estimator_->getState(State::YAW_BASE, aerial_robot_estimation::GROUND_TRUTH)[0]));
}

/* step2: also consider the offset tf from baselink to sensor */
/** ^{w}H_{b} * ^{b}H_{vo} * ^{vo}H_{w_vo} = ^{w}H_{w_vo} **/
world_offset_tf_ *= (sensor_tf_ * raw_sensor_tf.inverse());
/** step2: ^{vo}H_{b'} **/
tf::Transform vo_bdash_f = raw_sensor_tf * sensor_tf_.inverse(); // ^{vo}H_{b}
double r,p,y;
vo_bdash_f.getBasis().getRPY(r,p,y);
vo_bdash_f.setRotation(tf::createQuaternionFromYaw(y)); // ^{vo}H_{b'}

/** step3: ^{w}H_{vo} = ^{w}H_{b'} * ^{b'}H_{vo} **/
world_offset_tf_ = w_bdash_f * vo_bdash_f.inverse();

/* publish the offset tf if necessary */
geometry_msgs::TransformStamped static_transformStamped;
static_transformStamped.header.stamp = vo_msg->header.stamp;
static_transformStamped.header.frame_id = "world";
static_transformStamped.child_frame_id = vo_msg->header.frame_id;
tf::transformTFToMsg(world_offset_tf_, static_transformStamped.transform);
static_broadcaster_.sendTransform(static_transformStamped);

tf::Vector3 init_pos = w_bdash_f.getOrigin();

//double y, p, r; raw_sensor_tf.getBasis().getRPY(r, p, y);
tf::Vector3 init_pos = (world_offset_tf_ * raw_sensor_tf * sensor_tf_.inverse()).getOrigin();

for(auto& fuser : estimator_->getFuser(aerial_robot_estimation::EGOMOTION_ESTIMATE))
{
Expand Down Expand Up @@ -353,8 +366,8 @@ namespace sensor_plugin
tf::quaternionMsgToTF(vo_msg->pose.pose.orientation, raw_q);

// velocity:
tf::Vector3 raw_local_vel;
tf::vector3MsgToTF(vo_msg->twist.twist.linear, raw_local_vel);
tf::Vector3 raw_vel;
tf::vector3MsgToTF(vo_msg->twist.twist.linear, raw_vel);
/* get the latest orientation and omega */
baselink_r = estimator_->getOrientation(Frame::BASELINK, aerial_robot_estimation::EGOMOTION_ESTIMATE);
baselink_omega = estimator_->getAngularVel(Frame::BASELINK, aerial_robot_estimation::EGOMOTION_ESTIMATE);
Expand All @@ -365,11 +378,11 @@ namespace sensor_plugin
// int mode = estimator_->getStateStatus(State::YAW_BASE, aerial_robot_estimation::GROUND_TRUTH)?aerial_robot_estimation::GROUND_TRUTH:aerial_robot_estimation::EGOMOTION_ESTIMATE;
int mode = aerial_robot_estimation::EGOMOTION_ESTIMATE;

if (raw_local_vel == tf::Vector3(0.0,0.0,0.0))
if (raw_vel == tf::Vector3(0.0,0.0,0.0))
{
/* the odometry message does not contain velocity information, we have to calulcate by ourselves. */
tf::Transform delta_tf = prev_sensor_tf.inverse() * raw_sensor_tf;
raw_local_vel = delta_tf.getOrigin() / (curr_timestamp_ - prev_timestamp_);
raw_vel = delta_tf.getOrigin() / (curr_timestamp_ - prev_timestamp_);

reference_timestamp_ = (curr_timestamp_ + prev_timestamp_) / 2;
estimator_->findRotOmega(reference_timestamp_, mode, baselink_r, baselink_omega);
Expand All @@ -384,7 +397,16 @@ namespace sensor_plugin
}
}

raw_global_vel_ = baselink_r * ( sensor_tf_.getBasis() * raw_local_vel - baselink_omega.cross(sensor_tf_.getOrigin()));
raw_global_vel_ = world_offset_tf_.getBasis() * raw_vel;
if (local_vel_mode_)
{
// if the velocity is described in local frame (i.e., the sensor frame),
// we need to convert to global one
raw_global_vel_ = baselink_r * sensor_tf_.getBasis() * raw_vel;
}
// consider the offset between baselink and sensor frames
raw_global_vel_ -= baselink_r * baselink_omega.cross(sensor_tf_.getOrigin());


if(debug_verbose_)
{
Expand Down Expand Up @@ -600,6 +622,7 @@ namespace sensor_plugin
{
getParam<int>("fusion_mode", fusion_mode_, (int)ONLY_POS_MODE);
getParam<bool>("vio_mode", vio_mode_, false);
getParam<bool>("local_vel_mode", local_vel_mode_, true);
getParam<bool>("z_vel_mode", z_vel_mode_, false);
getParam<bool>("z_no_delay", z_no_delay_, false);
getParam<bool>("outdoor_no_vel_time_sync", outdoor_no_vel_time_sync_, false);
Expand Down
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