forward_trajectory.cpp

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#include <moveit/local_constraint_solver_plugins/forward_trajectory.h>
#include <moveit/local_planner/feedback_types.h>
#include <moveit/planning_scene/planning_scene.h>
#include <moveit/robot_state/conversions.h>
 
namespace
{
const rclcpp::Logger LOGGER = rclcpp::get_logger("local_planner_component");
// If stuck for this many iterations or more, abort the local planning action
constexpr size_t STUCK_ITERATIONS_THRESHOLD = 5;
constexpr double STUCK_THRESHOLD_RAD = 1e-4;  // L1-norm sum across all joints
}  // namespace
 
namespace moveit::hybrid_planning
{
bool ForwardTrajectory::initialize(const rclcpp::Node::SharedPtr& node,
                                   const planning_scene_monitor::PlanningSceneMonitorPtr& planning_scene_monitor,
                                   const std::string& /* unused */)
{
  // Load parameter & initialize member variables
  if (node->has_parameter("stop_before_collision"))
    node->get_parameter<bool>("stop_before_collision", stop_before_collision_);
  else
    stop_before_collision_ = node->declare_parameter<bool>("stop_before_collision", false);
  planning_scene_monitor_ = planning_scene_monitor;
  node_ = node;
  path_invalidation_event_send_ = false;
  num_iterations_stuck_ = 0;
  return true;
}
 
bool ForwardTrajectory::reset()
{
  num_iterations_stuck_ = 0;
  prev_waypoint_target_.reset();
  path_invalidation_event_send_ = false;
  return true;
};
 
moveit_msgs::action::LocalPlanner::Feedback
ForwardTrajectory::solve(const robot_trajectory::RobotTrajectory& local_trajectory,
                         const std::shared_ptr<const moveit_msgs::action::LocalPlanner::Goal> /* unused */,
                         trajectory_msgs::msg::JointTrajectory& local_solution)
{
  // A message every once in awhile is useful in case the local planner gets stuck
  RCLCPP_INFO_THROTTLE(LOGGER, *node_->get_clock(), 2000 /* ms */, "The local planner is solving...");
 
  // Create controller command trajectory
  robot_trajectory::RobotTrajectory robot_command(local_trajectory.getRobotModel(), local_trajectory.getGroupName());
 
  // Feedback
  moveit_msgs::action::LocalPlanner::Feedback feedback_result;
 
  // If this flag is set, ignore collisions
  if (!stop_before_collision_)
  {
    robot_command.addSuffixWayPoint(local_trajectory.getWayPoint(0), 0.0);
  }
  else
  {
    // Get current planning scene
    planning_scene_monitor_->updateFrameTransforms();
 
    moveit::core::RobotStatePtr current_state;
    bool is_path_valid = false;
    // Lock the planning scene as briefly as possible
    {
      planning_scene_monitor::LockedPlanningSceneRO locked_planning_scene(planning_scene_monitor_);
      current_state = std::make_shared<moveit::core::RobotState>(locked_planning_scene->getCurrentState());
      is_path_valid = locked_planning_scene->isPathValid(local_trajectory, local_trajectory.getGroupName(), false);
    }
 
    // Check if path is valid
    if (is_path_valid)
    {
      if (path_invalidation_event_send_)
      {
        path_invalidation_event_send_ = false;  // Reset flag
      }
      // Forward next waypoint to the robot controller
      robot_command.addSuffixWayPoint(local_trajectory.getWayPoint(0), 0.0);
    }
    else
    {
      if (!path_invalidation_event_send_)
      {  // Send feedback only once
        feedback_result.feedback = toString(LocalFeedbackEnum::COLLISION_AHEAD);
        path_invalidation_event_send_ = true;  // Set feedback flag
      }
      RCLCPP_INFO(LOGGER, "Collision ahead, holding current position");
      // Keep current position
      moveit::core::RobotState current_state_command(*current_state);
      if (current_state_command.hasVelocities())
      {
        current_state_command.zeroVelocities();
      }
      if (current_state_command.hasAccelerations())
      {
        current_state_command.zeroAccelerations();
      }
      robot_command.empty();
      robot_command.addSuffixWayPoint(*current_state, local_trajectory.getWayPointDurationFromPrevious(0));
    }
 
    // Detect if the local solver is stuck
    if (!prev_waypoint_target_)
    {
      // Just initialize if this is the first iteration
      prev_waypoint_target_ = robot_command.getFirstWayPointPtr();
    }
    else
    {
      if (prev_waypoint_target_->distance(*robot_command.getFirstWayPointPtr()) <= STUCK_THRESHOLD_RAD)
      {
        ++num_iterations_stuck_;
        if (num_iterations_stuck_ > STUCK_ITERATIONS_THRESHOLD)
        {
          num_iterations_stuck_ = 0;
          prev_waypoint_target_ = nullptr;
          feedback_result.feedback = toString(LocalFeedbackEnum::LOCAL_PLANNER_STUCK);
          path_invalidation_event_send_ = true;  // Set feedback flag
          RCLCPP_INFO(LOGGER, "The local planner has been stuck for several iterations. Aborting.");
        }
      }
      prev_waypoint_target_ = robot_command.getFirstWayPointPtr();
    }
  }
 
  // Transform robot trajectory into joint_trajectory message
  moveit_msgs::msg::RobotTrajectory robot_command_msg;
  robot_command.getRobotTrajectoryMsg(robot_command_msg);
  local_solution = robot_command_msg.joint_trajectory;
 
  return feedback_result;
}
}  // namespace moveit::hybrid_planning
 
#include <pluginlib/class_list_macros.hpp>
 
PLUGINLIB_EXPORT_CLASS(moveit::hybrid_planning::ForwardTrajectory,
                       moveit::hybrid_planning::LocalConstraintSolverInterface);