landing_target.cpp

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/*
 * Copyright 2015,2017,2019 Nuno Marques.
 *
 * This file is part of the mavros package and subject to the license terms
 * in the top-level LICENSE file of the mavros repository.
 * https://github.com/mavlink/mavros/tree/master/LICENSE.md
 */
 
#include <mavros/utils.h>
#include <mavros/mavros_plugin.h>
#include <mavros/setpoint_mixin.h>
#include <pluginlib/class_list_macros.hpp>
#include <eigen_conversions/eigen_msg.h>
 
#include <geometry_msgs/PoseStamped.h>
#include <geometry_msgs/Vector3Stamped.h>
#include <mavros_msgs/LandingTarget.h>
 
namespace mavros {
namespace extra_plugins {
using mavlink::common::MAV_FRAME;
using mavlink::common::LANDING_TARGET_TYPE;
 
class LandingTargetPlugin : public plugin::PluginBase,
        private plugin::TF2ListenerMixin<LandingTargetPlugin> {
public:
        LandingTargetPlugin() :
                nh("~landing_target"),
                send_tf(true),
                listen_tf(false),
                tf_rate(10.0),
                listen_lt(false),
                target_size_x(1.0),
                target_size_y(1.0),
                fov_x(2.0071286398),
                fov_y(2.0071286398),
                focal_length(2.8),
                image_width(640),
                image_height(480),
                mav_frame("LOCAL_NED"),
                land_target_type("VISION_FIDUCIAL")
        { }
 
        void initialize(UAS &uas_) override
        {
                PluginBase::initialize(uas_);
 
                // general params
                nh.param<std::string>("frame_id", frame_id, "landing_target_1");
                nh.param("listen_lt", listen_lt, false);        // subscribe to raw LadingTarget msg?
                nh.param<std::string>("mav_frame", mav_frame, "LOCAL_NED");
                frame = utils::mav_frame_from_str(mav_frame);   // MAV_FRAME index based on given frame name (If unknown, defaults to GENERIC)
 
                nh.param<std::string>("land_target_type", land_target_type, "VISION_FIDUCIAL");
                type = utils::landing_target_type_from_str(land_target_type);   // LANDING_TARGET_TYPE index based on given type name (If unknown, defaults to LIGHT_BEACON)
 
                // target size
                nh.param("target_size/x", target_size_x, 1.0);  // [meters]
                nh.param("target_size/y", target_size_y, 1.0);
 
                // image size
                nh.param<int>("image/width", image_width, 640); // [pixels]
                nh.param<int>("image/height", image_height, 480);
 
                // camera field-of-view -> should be precised using the calibrated camera intrinsics
                nh.param("camera/fov_x", fov_x, 2.0071286398);  // default: 115 [degrees]
                nh.param("camera/fov_y", fov_y, 2.0071286398);
                // camera focal length
                nh.param("camera/focal_length", focal_length, 2.8);     //ex: OpenMV Cam M7: 2.8 [mm]
 
                // tf subsection
                nh.param("tf/send", send_tf, true);
                nh.param("tf/listen", listen_tf, false);
                nh.param<std::string>("tf/frame_id", tf_frame_id, frame_id);
                nh.param<std::string>("tf/child_frame_id", tf_child_frame_id, "camera_center");
                nh.param("tf/rate_limit", tf_rate, 50.0);
 
                land_target_pub = nh.advertise<geometry_msgs::PoseStamped>("pose_in", 10);
                lt_marker_pub = nh.advertise<geometry_msgs::Vector3Stamped>("lt_marker", 10);
 
                if (listen_tf) {        // Listen to transform
                        ROS_INFO_STREAM_NAMED("landing_target", "Listen to landing_target transform " << tf_frame_id
                                                                                                      << " -> " << tf_child_frame_id);
                        tf2_start("LandingTargetTF", &LandingTargetPlugin::transform_cb);
                }
                else if (listen_lt) {   // Subscribe to LandingTarget msg
                        land_target_sub = nh.subscribe("raw", 10, &LandingTargetPlugin::landtarget_cb, this);
                }
                else {                  // Subscribe to PoseStamped msg
                        pose_sub = nh.subscribe("pose", 10, &LandingTargetPlugin::pose_cb, this);
                }
        }
 
        Subscriptions get_subscriptions() override
        {
                return {
                        make_handler(&LandingTargetPlugin::handle_landing_target)
                };
        }
 
private:
        friend class TF2ListenerMixin;
        ros::NodeHandle nh;
 
        bool send_tf;
        bool listen_tf;
        double tf_rate;
        ros::Time last_transform_stamp;
 
        bool listen_lt;
 
        std::string frame_id;
        std::string tf_frame_id;
        std::string tf_child_frame_id;
 
        ros::Publisher land_target_pub;
        ros::Publisher lt_marker_pub;
        ros::Subscriber land_target_sub;
        ros::Subscriber pose_sub;
 
        double target_size_x, target_size_y;
        double fov_x, fov_y;
        double focal_length;
        int image_width, image_height;
 
        MAV_FRAME frame;
        std::string mav_frame;
 
        LANDING_TARGET_TYPE type;
        std::string land_target_type;
 
        /* -*- low-level send -*- */
        void landing_target(uint64_t time_usec,
                uint8_t target_num,
                uint8_t frame,
                Eigen::Vector2f angle,
                float distance,
                Eigen::Vector2f size,
                Eigen::Vector3d pos,
                Eigen::Quaterniond q,
                uint8_t type,
                uint8_t position_valid)
        {
                mavlink::common::msg::LANDING_TARGET lt {};
 
                lt.time_usec = time_usec;
                lt.target_num = target_num;
                lt.frame = frame;
                lt.distance = distance;
                lt.type = type;
                lt.position_valid = position_valid;
                lt.angle_x = angle.x();
                lt.angle_y = angle.y();
                lt.size_x = size.x();
                lt.size_y = size.y();
                lt.x = pos.x();
                lt.y = pos.y();
                lt.z = pos.z();
 
                ftf::quaternion_to_mavlink(q, lt.q);
 
                UAS_FCU(m_uas)->send_message_ignore_drop(lt);
        }
 
        /* -*- mid-level helpers -*- */
        void inline cartesian_to_displacement(const Eigen::Vector3d &pos, Eigen::Vector2f &angle) {
                float angle_rad = atan(pos.y() / pos.x()) * (M_PI / 180.0);
 
                if (pos.x() > 0 && pos.y() > 0) {
                        angle.x() = angle_rad;
                        angle.y() = -angle_rad;
                }
                else if (pos.x() < 0 && pos.y() > 0) {
                        angle.x() = M_PI - angle_rad;
                        angle.y() = angle_rad;
                }
                else if (pos.x() < 0 && pos.y() < 0) {
                        angle.x() = M_PI + angle_rad;
                        angle.y() = M_PI - angle_rad;
                }
                else if (pos.x() > 0 && pos.y() < 0) {
                        angle.x() = -angle_rad;
                        angle.y() = M_PI + angle_rad;
                }
        }
 
        void send_landing_target(const ros::Time &stamp, const Eigen::Affine3d &tr) {
                auto pos = ftf::transform_frame_enu_ned(Eigen::Vector3d(tr.translation()));
 
                auto q = ftf::transform_orientation_enu_ned(
                        ftf::transform_orientation_baselink_aircraft(Eigen::Quaterniond(tr.rotation())));
 
                Eigen::Vector2f angle;
                Eigen::Vector2f size_rad;
                Eigen::Vector2f fov;
 
                // the norm of the position vector is considered the distance to the landing target
                float distance = pos.norm();
 
                // if the landing target type is a vision type, compute the angular offsets
                if (land_target_type.find("VISION")) {
                        angle.x() = (pos.x() - image_width / 2.0) * fov.x() / image_width;
                        angle.y() = (pos.y() - image_height / 2.0) * fov.y() / image_height;
                        size_rad = {2 * (M_PI / 180.0) * atan(target_size_x / (2 * focal_length)),
                                    2 * (M_PI / 180.0) * atan(target_size_y / (2 * focal_length))};
                }
                // else, the same values are computed considering the displacement relative to X and Y axes of the camera frame reference
                else {
                        cartesian_to_displacement(pos, angle);
                        size_rad = {2 * (M_PI / 180.0) * atan(target_size_x / (2 * distance)),
                                    2 * (M_PI / 180.0) * atan(target_size_y / (2 * distance))};
                }
 
                if (last_transform_stamp == stamp) {
                        ROS_DEBUG_THROTTLE_NAMED(10, "landing_target", "LT: Same transform as last one, dropped.");
                        return;
                }
                last_transform_stamp = stamp;
 
                auto rpy = ftf::quaternion_to_rpy(q);
 
                // the last char of frame_id is considered the number of the target
                uint8_t id = static_cast<uint8_t>(frame_id.back());
 
                ROS_DEBUG_THROTTLE_NAMED(10, "landing_target", "Tx landing target: "
                        "ID: %d frame: %s angular offset: X:%1.3frad, Y:%1.3frad) "
                        "distance: %1.3fm position: X:%1.3fm, Y:%1.3fm, Z:%1.3fm) "
                        "orientation: roll:%1.4frad pitch:%1.4frad yaw:%1.4frad "
                        "size: X:%1.3frad by Y:%1.3frad type: %s",
                        id, utils::to_string(static_cast<MAV_FRAME>(frame)).c_str(),
                        angle.x(), angle.y(), distance, pos.x(), pos.y(), pos.z(),
                        rpy.x(), rpy.y(), rpy.z(), size_rad.x(), size_rad.y(),
                        utils::to_string(static_cast<LANDING_TARGET_TYPE>(type)).c_str());
 
                landing_target(stamp.toNSec() / 1000,
                        id,
                        utils::enum_value(frame),                       // by default, in LOCAL_NED
                        angle,
                        distance,
                        size_rad,
                        pos,
                        q,
                        utils::enum_value(type),
                        1);                     // position is valid from the first received msg
        }
 
        void handle_landing_target(const mavlink::mavlink_message_t *msg, mavlink::common::msg::LANDING_TARGET &land_target) {
                auto position = ftf::transform_frame_ned_enu(Eigen::Vector3d(land_target.x, land_target.y, land_target.z));
                auto orientation = ftf::transform_orientation_aircraft_baselink(
                        ftf::transform_orientation_ned_enu(
                                ftf::mavlink_to_quaternion(land_target.q)));
 
                auto rpy = ftf::quaternion_to_rpy(orientation);
 
                ROS_DEBUG_THROTTLE_NAMED(10, "landing_target", "Rx landing target: "
                        "ID: %d frame: %s angular offset: X:%1.3frad, Y:%1.3frad) "
                        "distance: %1.3fm position: X:%1.3fm, Y:%1.3fm, Z:%1.3fm) "
                        "orientation: roll:%1.4frad pitch:%1.4frad yaw:%1.4frad "
                        "size: X:%1.3frad by Y:%1.3frad type: %s",
                        land_target.target_num, utils::to_string(static_cast<MAV_FRAME>(land_target.frame)).c_str(),
                        land_target.angle_x, land_target.angle_y, land_target.distance,
                        position.x(), position.y(), position.z(), rpy.x(), rpy.y(), rpy.z(), land_target.size_x, land_target.size_y,
                        utils::to_string(static_cast<LANDING_TARGET_TYPE>(land_target.type)).c_str());
 
                auto pose = boost::make_shared<geometry_msgs::PoseStamped>();
                pose->header = m_uas->synchronized_header(frame_id, land_target.time_usec);
 
                tf::pointEigenToMsg(position, pose->pose.position);
                tf::quaternionEigenToMsg(orientation, pose->pose.orientation);
 
                land_target_pub.publish(pose);
 
                if (send_tf) {
                        geometry_msgs::TransformStamped transform;
 
                        transform.header.stamp = pose->header.stamp;
                        transform.header.frame_id = "landing_target_" + boost::lexical_cast<std::string>(land_target.target_num);
                        transform.child_frame_id = tf_child_frame_id;
 
                        transform.transform.rotation = pose->pose.orientation;
                        tf::vectorEigenToMsg(position, transform.transform.translation);
 
                        m_uas->tf2_broadcaster.sendTransform(transform);
                }
 
                auto tg_size_msg = boost::make_shared<geometry_msgs::Vector3Stamped>();
                Eigen::Vector3d target_size(target_size_x, target_size_y, 0.0);
 
                tf::vectorEigenToMsg(target_size, tg_size_msg->vector);
 
                lt_marker_pub.publish(tg_size_msg);
        }
 
        /* -*- callbacks -*- */
        void transform_cb(const geometry_msgs::TransformStamped &transform) {
                Eigen::Affine3d tr;
                tf::transformMsgToEigen(transform.transform, tr);
 
                send_landing_target(transform.header.stamp, tr);
        }
 
        void pose_cb(const geometry_msgs::PoseStamped::ConstPtr &req) {
                Eigen::Affine3d tr;
                tf::poseMsgToEigen(req->pose, tr);
 
                send_landing_target(req->header.stamp, tr);
        }
 
        void landtarget_cb(const mavros_msgs::LandingTarget::ConstPtr &req) {
                Eigen::Affine3d tr;
                tf::poseMsgToEigen(req->pose, tr);
 
                auto position = ftf::transform_frame_enu_ned(Eigen::Vector3d(tr.translation()));
                auto orientation = ftf::transform_orientation_enu_ned(
                        ftf::transform_orientation_baselink_aircraft(Eigen::Quaterniond(tr.rotation())));
 
                landing_target( req->header.stamp.toNSec() / 1000,
                        req->target_num,
                        req->frame,                     // by default, in LOCAL_NED
                        Eigen::Vector2f(req->angle[0], req->angle[1]),
                        req->distance,
                        Eigen::Vector2f(req->size[0], req->size[1]),
                        position,
                        orientation,
                        req->type,
                        1);                             // position is valid from the first received msg
        }
};
}       // namespace extra_plugins
}       // namespace mavros
 
PLUGINLIB_EXPORT_CLASS(mavros::extra_plugins::LandingTargetPlugin, mavros::plugin::PluginBase)