CParameterizedTrajectoryGenerator.h

Go to the documentation of this file.

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/math/wrap2pi.h>
#include <mrpt/serialization/CSerializable.h>
#include <mrpt/core/round.h>
#include <mrpt/config/CConfigFileBase.h>
#include <mrpt/config/CLoadableOptions.h>
#include <mrpt/math/CPolygon.h>
#include <cstdint>
#include <mrpt/nav/holonomic/ClearanceDiagram.h>
#include <mrpt/poses/CPose2D.h>
#include <mrpt/kinematics/CVehicleVelCmd.h>

namespace mrpt
{
namespace opengl
{
class CSetOfLines;
}
}

namespace mrpt
{
namespace nav
{
/** Defines behaviors for where there is an obstacle *inside* the robot shape
  *right at the beginning of a PTG trajectory.
  *\ingroup nav_tpspace
  * \sa Used in CParameterizedTrajectoryGenerator::COLLISION_BEHAVIOR
  */
enum PTG_collision_behavior_t
{
    /** Favor getting back from too-close (almost collision) obstacles. */
    COLL_BEH_BACK_AWAY = 0,
    /** Totally dissallow any movement if there is any too-close (almost
       collision) obstacles. */
    COLL_BEH_STOP
};

/** \defgroup nav_tpspace TP-Space and PTG classes
  * \ingroup mrpt_nav_grp
  */

/** This is the base class for any user-defined PTG.
 *  There is a class factory interface in
 *CParameterizedTrajectoryGenerator::CreatePTG.
 *
 * Papers:
 *  - J.L. Blanco, J. Gonzalez-Jimenez, J.A. Fernandez-Madrigal, "Extending
 *Obstacle Avoidance Methods through Multiple Parameter-Space Transformations",
 *Autonomous Robots, vol. 24, no. 1, 2008.
 *http://ingmec.ual.es/~jlblanco/papers/blanco2008eoa_DRAFT.pdf
 *
 * Changes history:
 *  - 30/JUN/2004: Creation (JLBC)
 *  - 16/SEP/2004: Totally redesigned.
 *  - 15/SEP/2005: Totally rewritten again, for integration into MRPT
 *Applications Repository.
 *  - 19/JUL/2009: Simplified to use only STL data types, and created the class
 *factory interface.
 *  - MAY/2016: Refactored into CParameterizedTrajectoryGenerator,
 *CPTG_DiffDrive_CollisionGridBased, PTG classes renamed.
 *  - 2016-2018: Many features added to support "PTG continuation", dynamic
 *paths depending on vehicle speeds, etc.
 *
 *  \ingroup nav_tpspace
 */
class CParameterizedTrajectoryGenerator
    : public mrpt::serialization::CSerializable,
      public mrpt::config::CLoadableOptions
{
    DEFINE_VIRTUAL_SERIALIZABLE(CParameterizedTrajectoryGenerator)
   public:
    /** Default ctor. Must call `loadFromConfigFile()` before initialization */
    CParameterizedTrajectoryGenerator();
    /**  Destructor  */
    virtual ~CParameterizedTrajectoryGenerator() {}
    /** The class factory for creating a PTG from a list of parameters in a
      *section of a given config file (physical file or in memory).
      *  Possible parameters are:
      *   - Those explained in
      *CParameterizedTrajectoryGenerator::loadFromConfigFile()
      *   - Those explained in the specific PTG being created (see list of
      *derived classes)
      *
      * `ptgClassName` can be any PTG class name which has been registered as
      *any other
      * mrpt::serialization::CSerializable class.
      *
      * \exception std::logic_error On invalid or missing parameters.
      */
    static CParameterizedTrajectoryGenerator* CreatePTG(
        const std::string& ptgClassName,
        const mrpt::config::CConfigFileBase& cfg, const std::string& sSection,
        const std::string& sKeyPrefix);

    /** @name Virtual interface of each PTG implementation
     *  @{ */
    /** Gets a short textual description of the PTG and its parameters */
    virtual std::string getDescription() const = 0;

   protected:
    /** Must be called after setting all PTG parameters and before requesting
     * converting obstacles to TP-Space, inverseMap_WS2TP(), etc. */
    virtual void internal_initialize(
        const std::string& cacheFilename = std::string(),
        const bool verbose = true) = 0;
    /** This must be called to de-initialize the PTG if some parameter is to be
     * changed. After changing it, call initialize again */
    virtual void internal_deinitialize() = 0;

   public:
    /** Computes the closest (alpha,d) TP coordinates of the trajectory point
     * closest to the Workspace (WS)
     *   Cartesian coordinates (x,y), relative to the current robot frame.
      * \param[in] x X coordinate of the query point, relative to the robot
     * frame.
      * \param[in] y Y coordinate of the query point, relative to the robot
     * frame.
      * \param[out] out_k Trajectory parameter index (discretized alpha value,
     * 0-based index).
      * \param[out] out_d Trajectory distance, normalized such that D_max
     * becomes 1.
      *
      * \return true if the distance between (x,y) and the actual trajectory
     * point is below the given tolerance (in meters).
      */
    virtual bool inverseMap_WS2TP(
        double x, double y, int& out_k, double& out_normalized_d,
        double tolerance_dist = 0.10) const = 0;

    /** Returns the same than inverseMap_WS2TP() but without any additional
     * cost. The default implementation
      * just calls inverseMap_WS2TP() and discards (k,d). */
    virtual bool PTG_IsIntoDomain(double x, double y) const
    {
        int k;
        double d;
        return inverseMap_WS2TP(x, y, k, d);
    }

    /** Returns true if a given TP-Space point maps to a unique point in
     * Workspace, and viceversa. Default implementation returns `true`. */
    virtual bool isBijectiveAt(uint16_t k, uint32_t step) const { return true; }
    /** Converts a discretized "alpha" value into a feasible motion command or
     * action. See derived classes for the meaning of these actions */
    virtual mrpt::kinematics::CVehicleVelCmd::Ptr directionToMotionCommand(
        uint16_t k) const = 0;

    /** Returns an empty kinematic velocity command object of the type supported
     * by this PTG.
      * Can be queried to determine the expected kinematic interface of the PTG.
     */
    virtual mrpt::kinematics::CVehicleVelCmd::Ptr
        getSupportedKinematicVelocityCommand() const = 0;

    /** Dynamic state that may affect the PTG path parameterization. \ingroup
     * nav_reactive  */
    struct TNavDynamicState
    {
        /** Current vehicle velocity (local frame of reference) */
        mrpt::math::TTwist2D curVelLocal;
        /** Current relative target location */
        mrpt::math::TPose2D relTarget;
        /** Desired relative speed [0,1] at target. Default=0 */
        double targetRelSpeed;

        TNavDynamicState();
        bool operator==(const TNavDynamicState& o) const;
        inline bool operator!=(const TNavDynamicState& o) const
        {
            return !(*this == o);
        }
        void writeToStream(mrpt::serialization::CArchive& out) const;
        void readFromStream(mrpt::serialization::CArchive& in);
    };

   protected:
    /** Invoked when `m_nav_dyn_state` has changed; gives the PTG the
     * opportunity to react and parameterize paths depending on the
     * instantaneous conditions */
    virtual void onNewNavDynamicState() = 0;

   public:
    virtual void setRefDistance(const double refDist) { refDistance = refDist; }
    /** Access path `k` ([0,N-1]=>[-pi,pi] in alpha): number of discrete "steps"
     * along the trajectory.
      * May be actual steps from a numerical integration or an arbitrary small
     * length for analytical PTGs.
      * \sa getAlphaValuesCount() */
    virtual size_t getPathStepCount(uint16_t k) const = 0;

    /** Access path `k` ([0,N-1]=>[-pi,pi] in alpha): pose of the vehicle at
     * discrete step `step`.
      * \sa getPathStepCount(), getAlphaValuesCount() */
    virtual void getPathPose(
        uint16_t k, uint32_t step, mrpt::math::TPose2D& p) const = 0;

    /** Access path `k` ([0,N-1]=>[-pi,pi] in alpha): traversed distance at
     * discrete step `step`.
      * \return Distance in pseudometers (real distance, NOT normalized to [0,1]
     * for [0,refDist])
      * \sa getPathStepCount(), getAlphaValuesCount() */
    virtual double getPathDist(uint16_t k, uint32_t step) const = 0;

    /** Returns the duration (in seconds) of each "step"
    * \sa getPathStepCount() */
    virtual double getPathStepDuration() const = 0;

    /** Returns the maximum linear velocity expected from this PTG [m/s] */
    virtual double getMaxLinVel() const = 0;
    /** Returns the maximum angular velocity expected from this PTG [rad/s] */
    virtual double getMaxAngVel() const = 0;

    /** Access path `k` ([0,N-1]=>[-pi,pi] in alpha): largest step count for
     * which the traversed distance is < `dist`
      * \param[in] dist Distance in pseudometers (real distance, NOT normalized
     * to [0,1] for [0,refDist])
      * \return false if no step fulfills the condition for the given trajectory
     * `k` (e.g. out of reference distance).
      * Note that, anyway, the maximum distance (closest point) is returned in
     * `out_step`.
      * \sa getPathStepCount(), getAlphaValuesCount() */
    virtual bool getPathStepForDist(
        uint16_t k, double dist, uint32_t& out_step) const = 0;

    /** Updates the radial map of closest TP-Obstacles given a single obstacle
     * point at (ox,oy)
      * \param [in,out] tp_obstacles A vector of length `getAlphaValuesCount()`,
     * initialized with `initTPObstacles()` (collision-free ranges, in
     * "pseudometers", un-normalized).
      * \param [in] ox Obstacle point (X), relative coordinates wrt origin of
     * the PTG.
      * \param [in] oy Obstacle point (Y), relative coordinates wrt origin of
     * the PTG.
      * \note The length of tp_obstacles is not checked for efficiency since
     * this method is potentially called thousands of times per
      *  navigation timestap, so it is left to the user responsibility to
     * provide a valid buffer.
      * \note `tp_obstacles` must be initialized with initTPObstacle() before
     * call.
      */
    virtual void updateTPObstacle(
        double ox, double oy, std::vector<double>& tp_obstacles) const = 0;

    /** Like updateTPObstacle() but for one direction only (`k`) in TP-Space.
     * `tp_obstacle_k` must be initialized with initTPObstacleSingle() before
     * call (collision-free ranges, in "pseudometers", un-normalized). */
    virtual void updateTPObstacleSingle(
        double ox, double oy, uint16_t k, double& tp_obstacle_k) const = 0;

    /** Loads a set of default parameters into the PTG. Users normally will call
     * `loadFromConfigFile()` instead, this method is provided
      * exclusively for the PTG-configurator tool. */
    virtual void loadDefaultParams();

    /** Returns true if it is possible to stop sending velocity commands to the
     * robot and, still, the
      * robot controller will be able to keep following the last sent trajectory
     * ("NOP" velocity commands).
      * Default implementation returns "false". */
    virtual bool supportVelCmdNOP() const;

    /** Returns true if this PTG takes into account the desired velocity at
     * target. \sa updateNavDynamicState() */
    virtual bool supportSpeedAtTarget() const { return false; }
    /** Only for PTGs supporting supportVelCmdNOP(): this is the maximum time
     * (in seconds) for which the path
      * can be followed without re-issuing a new velcmd. Note that this is only
     * an absolute maximum duration,
      * navigation implementations will check for many other conditions. Default
     * method in the base virtual class returns 0.
      * \param path_k Queried path `k` index  [0,N-1] */
    virtual double maxTimeInVelCmdNOP(int path_k) const;

    /** Returns the actual distance (in meters) of the path, discounting
     * possible circular loops of the path (e.g. if it comes back to the
     * origin).
      * Default: refDistance */
    virtual double getActualUnloopedPathLength(uint16_t k) const
    {
        return this->refDistance;
    }

    /** Query the PTG for the relative priority factor (0,1) of this PTG, in
     * comparison to others, if the k-th path is to be selected. */
    virtual double evalPathRelativePriority(
        uint16_t k, double target_distance) const
    {
        return 1.0;
    }

    /** Returns an approximation of the robot radius. */
    virtual double getMaxRobotRadius() const = 0;
    /** Returns true if the point lies within the robot shape. */
    virtual bool isPointInsideRobotShape(
        const double x, const double y) const = 0;

    /** Evals the clearance from an obstacle (ox,oy) in coordinates relative to
     * the robot center. Zero or negative means collision. */
    virtual double evalClearanceToRobotShape(
        const double ox, const double oy) const = 0;

    /** @} */  // --- end of virtual methods

    /** To be invoked by the navigator *before* each navigation step, to let the
     * PTG to react to changing dynamic conditions. * \sa
     * onNewNavDynamicState(), m_nav_dyn_state  */
    void updateNavDynamicState(
        const TNavDynamicState& newState, const bool force_update = false);
    const TNavDynamicState& getCurrentNavDynamicState() const
    {
        return m_nav_dyn_state;
    }

    /** The path used as defaul output in, for example, debugDumpInFiles.
     * (Default="./reactivenav.logs/") */
    static std::string &OUTPUT_DEBUG_PATH_PREFIX();

    /** Must be called after setting all PTG parameters and before requesting
     * converting obstacles to TP-Space, inverseMap_WS2TP(), etc. */
    void initialize(
        const std::string& cacheFilename = std::string(),
        const bool verbose = true);
    /** This must be called to de-initialize the PTG if some parameter is to be
     * changed. After changing it, call initialize again */
    void deinitialize();
    /** Returns true if `initialize()` has been called and there was no errors,
     * so the PTG is ready to be queried for paths, obstacles, etc. */
    bool isInitialized() const;

    /** Get the number of different, discrete paths in this family */
    uint16_t getAlphaValuesCount() const { return m_alphaValuesCount; }
    /** Get the number of different, discrete paths in this family */
    uint16_t getPathCount() const { return m_alphaValuesCount; }
    /** Alpha value for the discrete corresponding value \sa alpha2index */
    double index2alpha(uint16_t k) const;
    static double index2alpha(uint16_t k, const unsigned int num_paths);

    /** Discrete index value for the corresponding alpha value \sa index2alpha
     */
    uint16_t alpha2index(double alpha) const;
    static uint16_t alpha2index(double alpha, const unsigned int num_paths);

    inline double getRefDistance() const { return refDistance; }
    /** Resizes and populates the initial appropriate contents in a vector of
     * tp-obstacles (collision-free ranges, in "pseudometers", un-normalized).
     * \sa updateTPObstacle()  */
    void initTPObstacles(std::vector<double>& TP_Obstacles) const;
    void initTPObstacleSingle(uint16_t k, double& TP_Obstacle_k) const;

    /** When used in path planning, a multiplying factor (default=1.0) for the
     * scores for this PTG. Assign values <1 to PTGs with low priority. */
    double getScorePriority() const { return m_score_priority; }
    void setScorePriorty(double prior) { m_score_priority = prior; }
    unsigned getClearanceStepCount() const { return m_clearance_num_points; }
    void setClearanceStepCount(const unsigned res)
    {
        m_clearance_num_points = res;
    }

    unsigned getClearanceDecimatedPaths() const
    {
        return m_clearance_decimated_paths;
    }
    void setClearanceDecimatedPaths(const unsigned num)
    {
        m_clearance_decimated_paths = num;
    }

    /** Returns the representation of one trajectory of this PTG as a 3D OpenGL
     * object (a simple curved line).
      * \param[in] k The 0-based index of the selected trajectory (discrete
     * "alpha" parameter).
      * \param[out] gl_obj Output object.
      * \param[in] decimate_distance Minimum distance between path points (in
     * meters).
      * \param[in] max_path_distance If >=0, cut the path at this distance (in
     * meters).
      */
    virtual void renderPathAsSimpleLine(
        const uint16_t k, mrpt::opengl::CSetOfLines& gl_obj,
        const double decimate_distance = 0.1,
        const double max_path_distance = -1.0) const;

    /** Dump PTG trajectories in four text files:
     * `./reactivenav.logs/PTGs/PTG%i_{x,y,phi,d}.txt`
      * Text files are loadable from MATLAB/Octave, and can be visualized with
     * the script `[MRPT_DIR]/scripts/viewPTG.m`
      * \note The directory "./reactivenav.logs/PTGs" will be created if doesn't
     * exist.
      * \return false on any error writing to disk.
      * \sa OUTPUT_DEBUG_PATH_PREFIX
      */
    bool debugDumpInFiles(const std::string& ptg_name) const;

    /** Parameters accepted by this base class:
     *   - `${sKeyPrefix}num_paths`: The number of different paths in this
     * family (number of discrete `alpha` values).
     *   - `${sKeyPrefix}ref_distance`: The maximum distance in PTGs [meters]
     *   - `${sKeyPrefix}score_priority`: When used in path planning, a
     * multiplying factor (default=1.0) for the scores for this PTG. Assign
     * values <1 to PTGs with low priority.
     */
    virtual void loadFromConfigFile(
        const mrpt::config::CConfigFileBase& cfg,
        const std::string& sSection) override;
    virtual void saveToConfigFile(
        mrpt::config::CConfigFileBase& cfg,
        const std::string& sSection) const override;

    /** Auxiliary function for rendering */
    virtual void add_robotShape_to_setOfLines(
        mrpt::opengl::CSetOfLines& gl_shape,
        const mrpt::poses::CPose2D& origin = mrpt::poses::CPose2D()) const = 0;

    /** Defines the behavior when there is an obstacle *inside* the robot shape
     * right at the beginning of a PTG trajectory.
     * Default value: COLL_BEH_BACK_AWAY
     */
    static PTG_collision_behavior_t &COLLISION_BEHAVIOR();

    /** Must be called to resize a CD to its correct size, before calling
     * updateClearance() */
    void initClearanceDiagram(ClearanceDiagram& cd) const;

    /** Updates the clearance diagram given one (ox,oy) obstacle point, in
     * coordinates relative
      * to the PTG path origin.
      * \param[in,out] cd The clearance will be updated here.
      * \sa m_clearance_dist_resolution
      */
    void updateClearance(
        const double ox, const double oy, ClearanceDiagram& cd) const;
    void updateClearancePost(
        ClearanceDiagram& cd, const std::vector<double>& TP_obstacles) const;

   protected:
    double refDistance;
    /** The number of discrete values for "alpha" between -PI and +PI. */
    uint16_t m_alphaValuesCount;
    double m_score_priority;
    /** Number of steps for the piecewise-constant approximation of clearance
     * from TPS distances [0,1] (Default=5) \sa updateClearance() */
    uint16_t m_clearance_num_points;
    /** Number of paths for the decimated paths analysis of clearance */
    uint16_t m_clearance_decimated_paths;
    /** Updated before each nav step by  */
    TNavDynamicState m_nav_dyn_state;
    /** Update in updateNavDynamicState(), contains the path index (k) for the
     * target. */
    uint16_t m_nav_dyn_state_target_k;

    static const uint16_t INVALID_PTG_PATH_INDEX = static_cast<uint16_t>(-1);

    bool m_is_initialized;

    /** To be called by implementors of updateTPObstacle() and
     * updateTPObstacleSingle() to
      * honor the user settings regarding COLLISION_BEHAVIOR.
      * \param new_tp_obs_dist The newly determiend collision-free ranges, in
     * "pseudometers", un-normalized, for some "k" direction.
      * \param inout_tp_obs The target where to store the new TP-Obs distance,
     * if it fulfills the criteria determined by the collision behavior.
      */
    void internal_TPObsDistancePostprocess(
        const double ox, const double oy, const double new_tp_obs_dist,
        double& inout_tp_obs) const;

    virtual void internal_readFromStream(mrpt::serialization::CArchive& in);
    virtual void internal_writeToStream(
        mrpt::serialization::CArchive& out) const;

   public:
    /** Evals the robot clearance for each robot pose along path `k`, for the
    * real distances in
    * the key of the map<>, then keep in the map value the minimum of its
    * current stored clearance,
    * or the computed clearance. In case of collision, clearance is zero.
    * \param treat_as_obstacle true: normal use for obstacles; false: compute
    * shortest distances to a target point (no collision)
    */
    virtual void evalClearanceSingleObstacle(
        const double ox, const double oy, const uint16_t k,
        ClearanceDiagram::dist2clearance_t& inout_realdist2clearance,
        bool treat_as_obstacle = true) const;

};  // end of class

/** A list of PTGs (smart pointers) */
using TListPTGPtr =
    std::vector<mrpt::nav::CParameterizedTrajectoryGenerator::Ptr>;

/** Base class for all PTGs using a 2D polygonal robot shape model.
 *  \ingroup nav_tpspace
 */
class CPTG_RobotShape_Polygonal : public CParameterizedTrajectoryGenerator
{
   public:
    CPTG_RobotShape_Polygonal();
    virtual ~CPTG_RobotShape_Polygonal();

    /** @name Robot shape
      * @{ **/
    /** Robot shape must be set before initialization, either from ctor params
     * or via this method. */
    void setRobotShape(const mrpt::math::CPolygon& robotShape);
    const mrpt::math::CPolygon& getRobotShape() const { return m_robotShape; }
    double getMaxRobotRadius() const override;
    virtual double evalClearanceToRobotShape(
        const double ox, const double oy) const override;
    /** @} */
    bool isPointInsideRobotShape(const double x, const double y) const override;
    void add_robotShape_to_setOfLines(
        mrpt::opengl::CSetOfLines& gl_shape,
        const mrpt::poses::CPose2D& origin =
            mrpt::poses::CPose2D()) const override;

   protected:
    /** Will be called whenever the robot shape is set / updated */
    virtual void internal_processNewRobotShape() = 0;
    mrpt::math::CPolygon m_robotShape;
    double m_robotMaxRadius;
    void loadShapeFromConfigFile(
        const mrpt::config::CConfigFileBase& source,
        const std::string& section);
    void saveToConfigFile(
        mrpt::config::CConfigFileBase& cfg,
        const std::string& sSection) const override;
    void internal_shape_loadFromStream(mrpt::serialization::CArchive& in);
    void internal_shape_saveToStream(mrpt::serialization::CArchive& out) const;
    /** Loads a set of default parameters; provided  exclusively for the
     * PTG-configurator tool. */
    void loadDefaultParams() override;
};

/** Base class for all PTGs using a 2D circular robot shape model.
 *  \ingroup nav_tpspace
 */
class CPTG_RobotShape_Circular : public CParameterizedTrajectoryGenerator
{
   public:
    CPTG_RobotShape_Circular();
    virtual ~CPTG_RobotShape_Circular();

    /** @name Robot shape
      * @{ **/
    /** Robot shape must be set before initialization, either from ctor params
     * or via this method. */
    void setRobotShapeRadius(const double robot_radius);
    double getRobotShapeRadius() const { return m_robotRadius; }
    double getMaxRobotRadius() const override;
    virtual double evalClearanceToRobotShape(
        const double ox, const double oy) const override;
    /** @} */
    void add_robotShape_to_setOfLines(
        mrpt::opengl::CSetOfLines& gl_shape,
        const mrpt::poses::CPose2D& origin =
            mrpt::poses::CPose2D()) const override;
    bool isPointInsideRobotShape(const double x, const double y) const override;

   protected:
    /** Will be called whenever the robot shape is set / updated */
    virtual void internal_processNewRobotShape() = 0;
    double m_robotRadius;
    void loadShapeFromConfigFile(
        const mrpt::config::CConfigFileBase& source,
        const std::string& section);
    void saveToConfigFile(
        mrpt::config::CConfigFileBase& cfg,
        const std::string& sSection) const override;
    void internal_shape_loadFromStream(mrpt::serialization::CArchive& in);
    void internal_shape_saveToStream(mrpt::serialization::CArchive& out) const;
    /** Loads a set of default parameters; provided  exclusively for the
     * PTG-configurator tool. */
    void loadDefaultParams() override;
};
}
}