speed_controller.cpp

// Copyright (c) 2018 Intel Corporation
// Copyright (c) 2020 Sarthak Mittal
//
// 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.
 
#include <string>
#include <memory>
#include <vector>
#include "nav2_util/geometry_utils.hpp"
 
#include "nav2_behavior_tree/plugins/decorator/speed_controller.hpp"
 
namespace nav2_behavior_tree
{
 
SpeedController::SpeedController(
  const std::string & name,
  const BT::NodeConfiguration & conf)
: BT::DecoratorNode(name, conf),
  first_tick_(false),
  period_(1.0),
  min_rate_(0.1),
  max_rate_(1.0),
  min_speed_(0.0),
  max_speed_(0.5)
{
  node_ = config().blackboard->get<rclcpp::Node::SharedPtr>("node");
 
  getInput("min_rate", min_rate_);
  getInput("max_rate", max_rate_);
  getInput("min_speed", min_speed_);
  getInput("max_speed", max_speed_);
 
  if (min_rate_ <= 0.0 || max_rate_ <= 0.0) {
    std::string err_msg = "SpeedController node cannot have rate <= 0.0";
    RCLCPP_FATAL(node_->get_logger(), "%s", err_msg.c_str());
    throw BT::BehaviorTreeException(err_msg);
  }
 
  d_rate_ = max_rate_ - min_rate_;
  d_speed_ = max_speed_ - min_speed_;
 
  std::string odom_topic;
  node_->get_parameter_or("odom_topic", odom_topic, std::string("odom"));
  odom_smoother_ = config().blackboard->get<std::shared_ptr<nav2_util::OdomSmoother>>(
    "odom_smoother");
}
 
inline BT::NodeStatus SpeedController::tick()
{
  if (status() == BT::NodeStatus::IDLE) {
    // Reset since we're starting a new iteration of
    // the speed controller (moving from IDLE to RUNNING)
    config().blackboard->get<std::vector<geometry_msgs::msg::PoseStamped>>("goals", goals_);
    config().blackboard->get<geometry_msgs::msg::PoseStamped>("goal", goal_);
    period_ = 1.0 / max_rate_;
    start_ = node_->now();
    first_tick_ = true;
  }
 
  std::vector<geometry_msgs::msg::PoseStamped> current_goals;
  config().blackboard->get<std::vector<geometry_msgs::msg::PoseStamped>>("goals", current_goals);
  geometry_msgs::msg::PoseStamped current_goal;
  config().blackboard->get<geometry_msgs::msg::PoseStamped>("goal", current_goal);
 
  if (goal_ != current_goal || goals_ != current_goals) {
    // Reset state and set period to max since we have a new goal
    period_ = 1.0 / max_rate_;
    start_ = node_->now();
    first_tick_ = true;
    goal_ = current_goal;
    goals_ = current_goals;
  }
 
  setStatus(BT::NodeStatus::RUNNING);
 
  auto elapsed = node_->now() - start_;
 
  // The child gets ticked the first time through and any time the period has
  // expired. In addition, once the child begins to run, it is ticked each time
  // 'til completion
  if (first_tick_ || (child_node_->status() == BT::NodeStatus::RUNNING) ||
    elapsed.seconds() >= period_)
  {
    first_tick_ = false;
 
    // update period if the last period is exceeded
    if (elapsed.seconds() >= period_) {
      updatePeriod();
      start_ = node_->now();
    }
 
    const BT::NodeStatus child_state = child_node_->executeTick();
 
    switch (child_state) {
      case BT::NodeStatus::RUNNING:
        return BT::NodeStatus::RUNNING;
 
      case BT::NodeStatus::SUCCESS:
        return BT::NodeStatus::SUCCESS;
 
      case BT::NodeStatus::FAILURE:
      default:
        return BT::NodeStatus::FAILURE;
    }
  }
 
  return status();
}
 
}  // namespace nav2_behavior_tree
 
#include "behaviortree_cpp_v3/bt_factory.h"
BT_REGISTER_NODES(factory)
{
  factory.registerNodeType<nav2_behavior_tree::SpeedController>("SpeedController");
}