OrientationOptimizer.h

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/**
 * This file is part of ArmarX.
 *
 * ArmarX is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * ArmarX is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * @author     Fabian Reister ( fabian dot reister at kit dot edu )
 * @date       2021
 * @copyright  http://www.gnu.org/licenses/gpl-2.0.txt
 *             GNU General Public License
 */
 
#pragma once
 
#include <optional>
 
#include <armarx/navigation/core/Trajectory.h>
 
namespace armarx::navigation::global_planning::optimization
{
 
    enum class RotationDirection
    {
        Any = 10,
        Clockwise = 1,
        CounterClockwise = 0
    };
 
    struct OrientationOptimizerParams
    {
        int iterations{5};
        float movementDirWeightStart{0.0F}; // inclusive
        float movementDirWeightEnd{0.5F}; // inclusive
 
        float smoothnessWeight{0.4F};
        float smoothnessWeightStartGoal{1.F};
 
        float priorStartWeight{1.F};
        float priorEndWeight{1.F};
 
        float startGoalDistanceThreshold{500};
 
        RotationDirection predefinedRotationDirection{RotationDirection::Any};
 
        /**
         * @brief Most the heading may turn per millimetre travelled [rad/mm].
         *
         * The rotation a profile needs is fixed by its start and goal; how much *path* it is
         * spread over is this optimizer's choice, and that choice decides whether the result can
         * be executed at all -- the yaw rate asked of the base is `yaw'(s) * v`.
         *
         * Nothing in the cost function is expressed per unit distance. The movement-direction
         * prior pulls every interior heading onto the path tangent and only the smoothness term
         * resists, so the profile holds the tangent as long as it can and then swings the whole
         * rotation across a narrow band -- the same band whether the path is one metre or six.
         * On ARMAR-7 that put a 116 deg rotation into 300 mm of a 3212 mm path and asked for
         * 3.9 rad/s against a 0.8 rad/s limit.
         *
         * The default is what a base holding 0.8 rad/s can turn while still making the 150 mm/s
         * the profile is floored at. Deliberately not an aron parameter: it is a property of the
         * drive, and every shipped config would have to grow a member to add it.
         */
        double maxTurnRate{0.8 / 150.0}; // [rad/mm]
 
        /**
         * @brief How short a segment has to be, relative to the path's own spacing, before the
         *        turn-rate check stops asking it anything.
         *
         * A segment far shorter than its neighbours carries no reliable direction: the heading
         * across it is `atan2` of numerical noise, and `dyaw/ds` on it is that noise divided by
         * nothing. It is a *position* defect, and `spfa::smoothing::GeometryLimits` already owns
         * it -- `findGeometryViolations` reports any segment under `minSegmentLength` (1 mm).
         *
         * The floor here is deliberately **relative** where that one is absolute, and an absolute
         * gate would be worse than useless: on a path whose spacing is legitimately around a
         * millimetre it excludes *every* segment, so the turn rate comes back as zero, the
         * smoothing loop never runs and `orientation-unturnable` can no longer fire at all. The
         * guard would go quiet exactly where it is needed. `TrajectoryFollowingController` hit
         * the same wall from the other side and lowered its own gate to 1e-3 mm for it. Only the
         * ratio to the path's own scale separates a defect from a small path, so do not unify
         * the three floors in this repo -- they answer different questions.
         *
         * A tenth, rather than something larger: the smoothing upstream can legitimately leave a
         * 40 mm segment among 200 mm ones, and excluding that would under-report a real turn
         * rate. The splice artefacts this exists for are three to four orders of magnitude below
         * their neighbours, so the margin is ample either way.
         */
        double degenerateSegmentFraction{0.1};
    };
 
    class OrientationOptimizer
    {
    public:
        using Params = OrientationOptimizerParams;
 
        OrientationOptimizer(const core::GlobalTrajectory& trajectory, const Params& params);
 
        struct OptimizationResult
        {
            std::optional<core::GlobalTrajectory> trajectory;
 
            /* //COMMENT IN FOR TEST CASE PLOTTING
            std::vector<double> initial;
            std::vector<double> prior; */
 
            operator bool() const noexcept
            {
                return trajectory.has_value();
            }
        };
 
        OptimizationResult optimize();
 
    protected:
    private:
        core::GlobalTrajectory trajectory;
 
        const Params params;
    };
} // namespace armarx::navigation::global_planning::optimization
 
// FIXME remove
namespace armarx::navigation::global_planning
{
    using namespace armarx::navigation::global_planning::optimization;
}