text: /*********************************************************************
   *
   * Software License Agreement (BSD License)
   *
   *  Copyright (c) 2016,
   *  TU Dortmund - Institute of Control Theory and Systems Engineering.
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   *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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   *
   * Author: Christoph Rösmann
   * Minor Modifications by: Phani Teja Singamaneni
   *********************************************************************/
  
  #ifndef RECOVERY_BEHAVIORS_H__
  #define RECOVERY_BEHAVIORS_H__
  
  
  #include <boost/circular_buffer.hpp>
  #include <geometry_msgs/Twist.h>
  #include <ros/ros.h>
  
  namespace hateb_local_planner
  {
  
  
  /**
   * @class FailureDetector
   * @brief This class implements methods in order to detect if the robot got stucked or is oscillating
   *
   * The StuckDetector analyzes the last N commanded velocities in order to detect whether the robot
   * might got stucked or oscillates between left/right/forward/backwards motions.
   */
  class FailureDetector
  {
  public:
  
    /**
     * @brief Default constructor
     */
    FailureDetector() {}
  
    /**
     * @brief destructor.
     */
    ~FailureDetector() {}
  
    /**
     * @brief Set buffer length (measurement history)
     * @param length number of measurements to be kept
     */
    void setBufferLength(int length) {buffer_.set_capacity(length);}
  
    /**
     * @brief Add a new twist measurement to the internal buffer and compute a new decision
     * @param twist geometry_msgs::Twist velocity information
     * @param v_max maximum forward translational velocity
     * @param v_backwards_max maximum backward translational velocity
     * @param omega_max maximum angular velocity
     * @param v_eps Threshold for the average normalized linear velocity in (0,1) that must not be exceded (e.g. 0.1)
     * @param omega_eps Threshold for the average normalized angular velocity in (0,1) that must not be exceded (e.g. 0.1)
     */
    void update(const geometry_msgs::Twist& twist, double v_max, double v_backwards_max, double omega_max, double v_eps, double omega_eps);
  
    /**
     * @brief Check if the robot got stucked
     *
     * This call does not compute the actual decision,
     * since it is computed within each update() invocation.
     * @return true if the robot got stucked, false otherwise.
     */
    bool isOscillating() const;
  
    /**
     * @brief Clear the current internal state
     *
     * This call also resets the internal buffer
     */
    void clear();
  
  protected:
  
      /** Variables to be monitored */
      struct VelMeasurement
      {
          double v = 0;
          double omega = 0;
      };
  
      /**
       * @brief Detect if the robot got stucked based on the current buffer content
       *
       * Afterwards the status might be checked using gotStucked();
       * @param v_eps Threshold for the average normalized linear velocity in (0,1) that must not be exceded (e.g. 0.1)
       * @param omega_eps Threshold for the average normalized angular velocity in (0,1) that must not be exceded (e.g. 0.1)
       * @return true if the robot got stucked, false otherwise
       */
      bool detect(double v_eps, double omega_eps);
  
  private:
  
      boost::circular_buffer<VelMeasurement> buffer_; //!< Circular buffer to store the last measurements @see setBufferLength
      bool oscillating_ = false; //!< Current state: true if robot is oscillating
  
  };
  
  
  } // namespace hateb_local_planner
  
  #endif /* RECOVERY_BEHAVIORS_H__ */
  