diff_drive_controller.hpp

// Copyright 2020 PAL Robotics S.L.
//
// 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: Bence Magyar, Enrique Fernández, Manuel Meraz
 */
 
#ifndef DIFF_DRIVE_CONTROLLER__DIFF_DRIVE_CONTROLLER_HPP_
#define DIFF_DRIVE_CONTROLLER__DIFF_DRIVE_CONTROLLER_HPP_
 
#include <chrono>
#include <memory>
#include <queue>
#include <string>
#include <vector>
 
#include "controller_interface/chainable_controller_interface.hpp"
#include "diff_drive_controller/odometry.hpp"
#include "diff_drive_controller/speed_limiter.hpp"
#include "geometry_msgs/msg/twist_stamped.hpp"
#include "nav_msgs/msg/odometry.hpp"
#include "odometry.hpp"
#include "rclcpp_lifecycle/state.hpp"
#include "realtime_tools/realtime_publisher.hpp"
#include "realtime_tools/realtime_thread_safe_box.hpp"
#include "tf2_msgs/msg/tf_message.hpp"
 
// auto-generated by generate_parameter_library
#include "diff_drive_controller/diff_drive_controller_parameters.hpp"
 
namespace diff_drive_controller
{
class DiffDriveController : public controller_interface::ChainableControllerInterface
{
  using TwistStamped = geometry_msgs::msg::TwistStamped;
 
public:
  DiffDriveController();
 
  controller_interface::InterfaceConfiguration command_interface_configuration() const override;
 
  controller_interface::InterfaceConfiguration state_interface_configuration() const override;
 
  // Chainable controller replaces update() with the following two functions
  controller_interface::return_type update_reference_from_subscribers(
    const rclcpp::Time & time, const rclcpp::Duration & period) override;
 
  controller_interface::return_type update_and_write_commands(
    const rclcpp::Time & time, const rclcpp::Duration & period) override;
 
  controller_interface::CallbackReturn on_init() override;
 
  controller_interface::CallbackReturn on_configure(
    const rclcpp_lifecycle::State & previous_state) override;
 
  controller_interface::CallbackReturn on_activate(
    const rclcpp_lifecycle::State & previous_state) override;
 
  controller_interface::CallbackReturn on_deactivate(
    const rclcpp_lifecycle::State & previous_state) override;
 
  controller_interface::CallbackReturn on_cleanup(
    const rclcpp_lifecycle::State & previous_state) override;
 
  controller_interface::CallbackReturn on_error(
    const rclcpp_lifecycle::State & previous_state) override;
 
protected:
  bool on_set_chained_mode(bool chained_mode) override;
 
  std::vector<hardware_interface::CommandInterface::SharedPtr> on_export_reference_interfaces_list()
    override;
 
  struct WheelHandle
  {
    std::optional<std::reference_wrapper<const hardware_interface::LoanedStateInterface>> feedback;
    std::reference_wrapper<hardware_interface::LoanedCommandInterface> velocity;
  };
 
  const char * feedback_type() const;
  controller_interface::CallbackReturn configure_side(
    const std::string & side, const std::vector<std::string> & wheel_names,
    std::vector<WheelHandle> & registered_handles);
 
  std::vector<WheelHandle> registered_left_wheel_handles_;
  std::vector<WheelHandle> registered_right_wheel_handles_;
 
  // Parameters from ROS for diff_drive_controller
  std::shared_ptr<ParamListener> param_listener_;
  Params params_;
  /* Number of wheels on each side of the robot. This is important to take the wheels slip into
   * account when multiple wheels on each side are present. If there are more wheels then control
   * signals for each side, you should enter number for control signals. For example, Husky has two
   * wheels on each side, but they use one control signal, in this case '1' is the correct value of
   * the parameter. */
  int wheels_per_side_;
 
  Odometry odometry_;
 
  // Timeout to consider cmd_vel commands old
  rclcpp::Duration cmd_vel_timeout_ = rclcpp::Duration::from_seconds(0.5);
 
  std::shared_ptr<rclcpp::Publisher<nav_msgs::msg::Odometry>> odometry_publisher_ = nullptr;
  std::shared_ptr<realtime_tools::RealtimePublisher<nav_msgs::msg::Odometry>>
    realtime_odometry_publisher_ = nullptr;
  nav_msgs::msg::Odometry odometry_message_;
 
  std::shared_ptr<rclcpp::Publisher<tf2_msgs::msg::TFMessage>> odometry_transform_publisher_ =
    nullptr;
  std::shared_ptr<realtime_tools::RealtimePublisher<tf2_msgs::msg::TFMessage>>
    realtime_odometry_transform_publisher_ = nullptr;
  tf2_msgs::msg::TFMessage odometry_transform_message_;
 
  bool subscriber_is_active_ = false;
  rclcpp::Subscription<TwistStamped>::SharedPtr velocity_command_subscriber_ = nullptr;
 
  // the realtime container to exchange the reference from subscriber
  realtime_tools::RealtimeThreadSafeBox<TwistStamped> received_velocity_msg_;
  // save the last reference in case of unable to get value from box
  TwistStamped command_msg_;
 
  std::queue<std::array<double, 2>> previous_two_commands_;
  // speed limiters
  std::unique_ptr<SpeedLimiter> limiter_linear_;
  std::unique_ptr<SpeedLimiter> limiter_angular_;
 
  std::shared_ptr<rclcpp::Publisher<TwistStamped>> limited_velocity_publisher_ = nullptr;
  std::shared_ptr<realtime_tools::RealtimePublisher<TwistStamped>>
    realtime_limited_velocity_publisher_ = nullptr;
  TwistStamped limited_velocity_message_;
 
  rclcpp::Time previous_update_timestamp_{0};
 
  // publish rate limiter
  double publish_rate_ = 50.0;
  rclcpp::Duration publish_period_ = rclcpp::Duration::from_nanoseconds(0);
  rclcpp::Time previous_publish_timestamp_{0, 0, RCL_CLOCK_UNINITIALIZED};
 
  bool command_timed_out_ = false;
 
  bool reset();
  void halt();
 
private:
  void reset_buffers();
};
}  // namespace diff_drive_controller
#endif  // DIFF_DRIVE_CONTROLLER__DIFF_DRIVE_CONTROLLER_HPP_