joint_command_topic_hardware_interface.hpp

// Copyright 2026 ros2_control Development Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
/* Author: Kamalkant Thangaraju */
 
#pragma once
 
// C++
#include <map>
#include <memory>
#include <string>
#include <vector>
 
// ROS
#include <hardware_interface/system_interface.hpp>
#include <hardware_interface/types/hardware_component_interface_params.hpp>
#include <rclcpp/node.hpp>
#include <rclcpp/publisher.hpp>
#include <rclcpp/subscription.hpp>
#include <realtime_tools/realtime_buffer.hpp>
 
#include <control_msgs/msg/joint_command.hpp>
#include <sensor_msgs/msg/joint_state.hpp>
 
namespace joint_command_topic_hardware_interface
{
using CallbackReturn = rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn;
 
class JointCommandTopicSystem : public hardware_interface::SystemInterface
{
public:
  CallbackReturn on_init(const hardware_interface::HardwareComponentInterfaceParams& params) override;
 
  hardware_interface::return_type read(const rclcpp::Time& time, const rclcpp::Duration& period) override;
 
  hardware_interface::return_type write(const rclcpp::Time& time, const rclcpp::Duration& period) override;
 
private:
  struct JointCommandGroup
  {
    std::string interface_name;
    std::vector<std::string> joint_names;
    std::vector<std::string> command_keys;
    control_msgs::msg::JointCommand msg;
  };
 
  rclcpp::Subscription<sensor_msgs::msg::JointState>::SharedPtr topic_based_joint_states_subscriber_;
  std::map<std::string, rclcpp::Publisher<control_msgs::msg::JointCommand>::SharedPtr>
      topic_based_joint_command_publishers_;
  std::map<std::string, JointCommandGroup> command_groups_;
  realtime_tools::RealtimeBuffer<sensor_msgs::msg::JointState> latest_joint_state_;
  bool sum_wrapped_joint_states_{ false };
 
  double trigger_joint_command_threshold_ = 1e-5;
};
 
}  // namespace joint_command_topic_hardware_interface