CPTG_DiffDrive_C.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include "nav-precomp.h"  // Precomp header

#include <mrpt/math/wrap2pi.h>
#include <mrpt/nav/tpspace/CPTG_DiffDrive_C.h>
#include <mrpt/serialization/CArchive.h>

using namespace mrpt;
using namespace mrpt::nav;
using namespace mrpt::system;

IMPLEMENTS_SERIALIZABLE(
    CPTG_DiffDrive_C, CParameterizedTrajectoryGenerator, mrpt::nav)

void CPTG_DiffDrive_C::loadFromConfigFile(
    const mrpt::config::CConfigFileBase& cfg, const std::string& sSection)
{
    CPTG_DiffDrive_CollisionGridBased::loadFromConfigFile(cfg, sSection);

    MRPT_LOAD_CONFIG_VAR_NO_DEFAULT(K, double, cfg, sSection);
}
void CPTG_DiffDrive_C::saveToConfigFile(
    mrpt::config::CConfigFileBase& cfg, const std::string& sSection) const
{
    MRPT_START
    const int WN = 25, WV = 30;
    CPTG_DiffDrive_CollisionGridBased::saveToConfigFile(cfg, sSection);

    cfg.write(
        sSection, "K", K, WN, WV,
        "K=+1 forward paths; K=-1 for backwards paths.");

    MRPT_END
}

void CPTG_DiffDrive_C::serializeFrom(
    mrpt::serialization::CArchive& in, uint8_t version)
{
    CPTG_DiffDrive_CollisionGridBased::internal_readFromStream(in);

    switch (version)
    {
        case 0:
            in >> K;
            break;
        default:
            MRPT_THROW_UNKNOWN_SERIALIZATION_VERSION(version);
    };
}

uint8_t CPTG_DiffDrive_C::serializeGetVersion() const { return 0; }
void CPTG_DiffDrive_C::serializeTo(mrpt::serialization::CArchive& out) const
{
    CPTG_DiffDrive_CollisionGridBased::internal_writeToStream(out);
    out << K;
}

std::string CPTG_DiffDrive_C::getDescription() const
{
    return mrpt::format("CPTG_DiffDrive_C,K=%i", (int)K);
}

void CPTG_DiffDrive_C::ptgDiffDriveSteeringFunction(
    [[maybe_unused]] float alpha, [[maybe_unused]] float t,
    [[maybe_unused]] float x, [[maybe_unused]] float y,
    [[maybe_unused]] float phi, [[maybe_unused]] float& v,
    [[maybe_unused]] float& w) const
{
    // (v,w)
    v = V_MAX * sign(K);
    // Use a linear mapping:  (Old was: w = tan( alpha/2 ) * W_MAX * sign(K))
    w = (alpha / M_PI) * W_MAX * sign(K);
}

bool CPTG_DiffDrive_C::PTG_IsIntoDomain(
    [[maybe_unused]] double x, [[maybe_unused]] double y) const
{
    return true;
}

bool CPTG_DiffDrive_C::inverseMap_WS2TP(
    double x, double y, int& k_out, double& d_out,
    [[maybe_unused]] double tolerance_dist) const
{
    bool is_exact = true;
    if (y != 0)
    {
        double R = (x * x + y * y) / (2 * y);
        const double Rmin = std::abs(V_MAX / W_MAX);

        double theta;

        if (K > 0)
        {
            if (y > 0)
                theta = atan2((double)x, fabs(R) - y);
            else
                theta = atan2((double)x, y + fabs(R));
        }
        else
        {
            if (y > 0)
                theta = atan2(-(double)x, fabs(R) - y);
            else
                theta = atan2(-(double)x, y + fabs(R));
        }

        // Arc length must be possitive [0,2*pi]
        mrpt::math::wrapTo2PiInPlace(theta);

        // Distance thru arc:
        d_out = (float)(theta * (fabs(R) + turningRadiusReference));

        if (std::abs(R) < Rmin)
        {
            is_exact = false;
            R = Rmin * mrpt::sign(R);
        }

        // Was: a = 2*atan( V_MAX / (W_MAX*R) );
        const double a = M_PI * V_MAX / (W_MAX * R);
        k_out = alpha2index((float)a);
    }
    else
    {
        if (sign(x) == sign(K))
        {
            k_out = alpha2index(0);
            d_out = x;
            is_exact = true;
        }
        else
        {
            k_out = m_alphaValuesCount - 1;
            d_out = 1e+3;
            is_exact = false;
        }
    }

    // Normalize:
    d_out = d_out / refDistance;

    ASSERT_ABOVEEQ_(k_out, 0);
    ASSERT_BELOW_(k_out, m_alphaValuesCount);

    return is_exact;
}

void CPTG_DiffDrive_C::loadDefaultParams()
{
    CPTG_DiffDrive_CollisionGridBased::loadDefaultParams();
    K = +1.0;
}