oscillation.cpp

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#include "dwb_critics/oscillation.hpp"
#include <chrono>
#include <cmath>
#include <string>
#include <vector>
#include "dwb_core/exceptions.hpp"
#include "pluginlib/class_list_macros.hpp"
#include "angles/angles.h"
 
PLUGINLIB_EXPORT_CLASS(dwb_critics::OscillationCritic, dwb_core::TrajectoryCritic)
 
namespace dwb_critics
{
 
 
OscillationCritic::CommandTrend::CommandTrend()
{
  reset();
}
 
void OscillationCritic::CommandTrend::reset()
{
  sign_ = Sign::ZERO;
  positive_only_ = false;
  negative_only_ = false;
}
 
bool OscillationCritic::CommandTrend::update(double velocity)
{
  bool flag_set = false;
  if (velocity < 0.0) {
    if (sign_ == Sign::POSITIVE) {
      negative_only_ = true;
      flag_set = true;
    }
    sign_ = Sign::NEGATIVE;
  } else if (velocity > 0.0) {
    if (sign_ == Sign::NEGATIVE) {
      positive_only_ = true;
      flag_set = true;
    }
    sign_ = Sign::POSITIVE;
  }
  return flag_set;
}
 
bool OscillationCritic::CommandTrend::isOscillating(double velocity)
{
  return (positive_only_ && velocity < 0.0) || (negative_only_ && velocity > 0.0);
}
 
bool OscillationCritic::CommandTrend::hasSignFlipped()
{
  return positive_only_ || negative_only_;
}
 
void OscillationCritic::onInit()
{
  auto node = node_.lock();
  if (!node) {
    throw std::runtime_error{"Failed to lock node"};
  }
 
  clock_ = node->get_clock();
 
  oscillation_reset_dist_ = node->declare_or_get_parameter(
    dwb_plugin_name_ + "." + name_ +
    ".oscillation_reset_dist", 0.05);
  oscillation_reset_dist_sq_ = oscillation_reset_dist_ * oscillation_reset_dist_;
  oscillation_reset_angle_ = node->declare_or_get_parameter(
    dwb_plugin_name_ + "." + name_ + ".oscillation_reset_angle", 0.2);
  oscillation_reset_time_ = rclcpp::Duration::from_seconds(
    node->declare_or_get_parameter(
      dwb_plugin_name_ + "." + name_ + ".oscillation_reset_time", -1.0));
 
  x_only_threshold_ = node->declare_or_get_parameter(
    dwb_plugin_name_ + "." + name_ + ".x_only_threshold", 0.05);
 
  reset();
}
 
bool OscillationCritic::prepare(
  const geometry_msgs::msg::Pose & pose,
  const nav_2d_msgs::msg::Twist2D &,
  const geometry_msgs::msg::Pose &,
  const nav_msgs::msg::Path &)
{
  pose_ = pose;
  return true;
}
 
void OscillationCritic::debrief(const nav_2d_msgs::msg::Twist2D & cmd_vel)
{
  if (setOscillationFlags(cmd_vel)) {
    prev_stationary_pose_ = pose_;
    prev_reset_time_ = clock_->now();
  }
 
  // if we've got restrictions... check if we can reset any oscillation flags
  if (x_trend_.hasSignFlipped() || y_trend_.hasSignFlipped() || theta_trend_.hasSignFlipped()) {
    // Reset flags if enough time or distance has passed
    if (resetAvailable()) {
      reset();
    }
  }
}
bool OscillationCritic::resetAvailable()
{
  if (oscillation_reset_dist_ >= 0.0) {
    double x_diff = pose_.position.x - prev_stationary_pose_.position.x;
    double y_diff = pose_.position.y - prev_stationary_pose_.position.y;
    double sq_dist = x_diff * x_diff + y_diff * y_diff;
    if (sq_dist > oscillation_reset_dist_sq_) {
      return true;
    }
  }
  if (oscillation_reset_angle_ >= 0.0) {
    tf2::Quaternion pose_q, prev_stationary_pose_q;
    tf2::fromMsg(pose_.orientation, pose_q);
    tf2::fromMsg(prev_stationary_pose_.orientation, prev_stationary_pose_q);
 
    double th_diff = angles::shortest_angular_distance(
      tf2::getYaw(pose_q), tf2::getYaw(prev_stationary_pose_q));
 
    if (fabs(th_diff) > oscillation_reset_angle_) {
      return true;
    }
  }
  if (oscillation_reset_time_ >= rclcpp::Duration::from_seconds(0.0)) {
    auto t_diff = (clock_->now() - prev_reset_time_);
    if (t_diff > oscillation_reset_time_) {
      return true;
    }
  }
  return false;
}
 
void OscillationCritic::reset()
{
  x_trend_.reset();
  y_trend_.reset();
  theta_trend_.reset();
}
 
bool OscillationCritic::setOscillationFlags(const nav_2d_msgs::msg::Twist2D & cmd_vel)
{
  bool flag_set = false;
  // set oscillation flags for moving forward and backward
  flag_set |= x_trend_.update(cmd_vel.x);
 
  // we'll only set flags for strafing and rotating when we're not moving forward at all
  if (x_only_threshold_ < 0.0 || fabs(cmd_vel.x) <= x_only_threshold_) {
    flag_set |= y_trend_.update(cmd_vel.y);
    flag_set |= theta_trend_.update(cmd_vel.theta);
  }
  return flag_set;
}
 
double OscillationCritic::scoreTrajectory(const dwb_msgs::msg::Trajectory2D & traj)
{
  if (x_trend_.isOscillating(traj.velocity.x) ||
    y_trend_.isOscillating(traj.velocity.y) ||
    theta_trend_.isOscillating(traj.velocity.theta))
  {
    throw dwb_core::
          IllegalTrajectoryException(name_, "Trajectory is oscillating.");
  }
  return 0.0;
}
 
}  // namespace dwb_critics