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| 1 | +// Copyright (c) 2023 Open Navigation LLC |
| 2 | +// |
| 3 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +// you may not use this file except in compliance with the License. |
| 5 | +// You may obtain a copy of the License at |
| 6 | +// |
| 7 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +// |
| 9 | +// Unless required by applicable law or agreed to in writing, software |
| 10 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +// See the License for the specific language governing permissions and |
| 13 | +// limitations under the License. |
| 14 | + |
| 15 | +#ifndef NAV2_UTIL__BASE_FOOTPRINT_PUBLISHER_HPP_ |
| 16 | +#define NAV2_UTIL__BASE_FOOTPRINT_PUBLISHER_HPP_ |
| 17 | + |
| 18 | +#include <string> |
| 19 | +#include <memory> |
| 20 | + |
| 21 | +#include "rclcpp/rclcpp.hpp" |
| 22 | +#include "tf2_msgs/msg/tf_message.hpp" |
| 23 | +#include "geometry_msgs/msg/transform_stamped.hpp" |
| 24 | +#include "tf2_ros/create_timer_ros.h" |
| 25 | +#include "tf2_ros/transform_listener.h" |
| 26 | +#include "tf2_ros/transform_broadcaster.h" |
| 27 | +#include "tf2_ros/buffer.h" |
| 28 | +#include "tf2_geometry_msgs/tf2_geometry_msgs.hpp" |
| 29 | +#include "tf2/utils.h" |
| 30 | + |
| 31 | +namespace nav2_util |
| 32 | +{ |
| 33 | + |
| 34 | +/** |
| 35 | + * @brief A TF2 listener that overrides the subscription callback |
| 36 | + * to inject base footprint publisher removing Z, Pitch, and Roll for |
| 37 | + * 3D state estimation but desiring a 2D frame for navigation, visualization, or other reasons |
| 38 | + */ |
| 39 | +class BaseFootprintPublisherListener : public tf2_ros::TransformListener |
| 40 | +{ |
| 41 | +public: |
| 42 | + BaseFootprintPublisherListener(tf2::BufferCore & buffer, bool spin_thread, rclcpp::Node & node) |
| 43 | + : tf2_ros::TransformListener(buffer, spin_thread) |
| 44 | + { |
| 45 | + node.declare_parameter( |
| 46 | + "base_link_frame", rclcpp::ParameterValue(std::string("base_link"))); |
| 47 | + node.declare_parameter( |
| 48 | + "base_footprint_frame", rclcpp::ParameterValue(std::string("base_footprint"))); |
| 49 | + base_link_frame_ = node.get_parameter("base_link_frame").as_string(); |
| 50 | + base_footprint_frame_ = node.get_parameter("base_footprint_frame").as_string(); |
| 51 | + tf_broadcaster_ = std::make_shared<tf2_ros::TransformBroadcaster>(node); |
| 52 | + } |
| 53 | + |
| 54 | + /** |
| 55 | + * @brief Overrides TF2 subscription callback to inject base footprint publisher |
| 56 | + */ |
| 57 | + void subscription_callback(tf2_msgs::msg::TFMessage::ConstSharedPtr msg, bool is_static) override |
| 58 | + { |
| 59 | + TransformListener::subscription_callback(msg, is_static); |
| 60 | + |
| 61 | + if (is_static) { |
| 62 | + return; |
| 63 | + } |
| 64 | + |
| 65 | + for (unsigned int i = 0; i != msg->transforms.size(); i++) { |
| 66 | + auto & t = msg->transforms[i]; |
| 67 | + if (t.child_frame_id == base_link_frame_) { |
| 68 | + geometry_msgs::msg::TransformStamped transform; |
| 69 | + transform.header.stamp = t.header.stamp; |
| 70 | + transform.header.frame_id = base_link_frame_; |
| 71 | + transform.child_frame_id = base_footprint_frame_; |
| 72 | + |
| 73 | + // Project to Z-zero |
| 74 | + transform.transform.translation = t.transform.translation; |
| 75 | + transform.transform.translation.z = 0.0; |
| 76 | + |
| 77 | + // Remove Roll and Pitch |
| 78 | + tf2::Quaternion q; |
| 79 | + q.setRPY(0, 0, tf2::getYaw(t.transform.rotation)); |
| 80 | + q.normalize(); |
| 81 | + transform.transform.rotation.x = q.x(); |
| 82 | + transform.transform.rotation.y = q.y(); |
| 83 | + transform.transform.rotation.z = q.z(); |
| 84 | + transform.transform.rotation.w = q.w(); |
| 85 | + |
| 86 | + tf_broadcaster_->sendTransform(transform); |
| 87 | + return; |
| 88 | + } |
| 89 | + } |
| 90 | + } |
| 91 | + |
| 92 | +protected: |
| 93 | + std::shared_ptr<tf2_ros::TransformBroadcaster> tf_broadcaster_; |
| 94 | + std::string base_link_frame_, base_footprint_frame_; |
| 95 | +}; |
| 96 | + |
| 97 | +/** |
| 98 | + * @class nav2_util::BaseFootprintPublisher |
| 99 | + * @brief Republishes the ``base_link`` frame as ``base_footprint`` |
| 100 | + * stripping away the Z, Roll, and Pitch of the full 3D state to provide |
| 101 | + * a 2D projection for navigation when state estimation is full 3D |
| 102 | + */ |
| 103 | +class BaseFootprintPublisher : public rclcpp::Node |
| 104 | +{ |
| 105 | +public: |
| 106 | + /** |
| 107 | + * @brief A constructor |
| 108 | + */ |
| 109 | + explicit BaseFootprintPublisher(const rclcpp::NodeOptions & options = rclcpp::NodeOptions()) |
| 110 | + : Node("base_footprint_publisher", options) |
| 111 | + { |
| 112 | + RCLCPP_INFO(get_logger(), "Creating base footprint publisher"); |
| 113 | + tf_buffer_ = std::make_shared<tf2_ros::Buffer>(get_clock()); |
| 114 | + auto timer_interface = std::make_shared<tf2_ros::CreateTimerROS>( |
| 115 | + get_node_base_interface(), |
| 116 | + get_node_timers_interface()); |
| 117 | + tf_buffer_->setCreateTimerInterface(timer_interface); |
| 118 | + listener_publisher_ = std::make_shared<BaseFootprintPublisherListener>( |
| 119 | + *tf_buffer_, true, *this); |
| 120 | + } |
| 121 | + |
| 122 | +protected: |
| 123 | + std::shared_ptr<tf2_ros::Buffer> tf_buffer_; |
| 124 | + std::shared_ptr<BaseFootprintPublisherListener> listener_publisher_; |
| 125 | +}; |
| 126 | + |
| 127 | +} // end namespace nav2_util |
| 128 | + |
| 129 | +#endif // NAV2_UTIL__BASE_FOOTPRINT_PUBLISHER_HPP_ |
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