Program Listing for File motion_models.hpp

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// Copyright (c) 2022 Samsung Research America, @artofnothingness Alexey Budyakov
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef NAV2_MPPI_CONTROLLER__MOTION_MODELS_HPP_
#define NAV2_MPPI_CONTROLLER__MOTION_MODELS_HPP_

#include <cstdint>

#include "nav2_mppi_controller/models/control_sequence.hpp"
#include "nav2_mppi_controller/models/state.hpp"
#include <xtensor/xmath.hpp>
#include <xtensor/xmasked_view.hpp>
#include <xtensor/xview.hpp>
#include <xtensor/xnoalias.hpp>

#include "nav2_mppi_controller/tools/parameters_handler.hpp"

namespace mppi
{

class MotionModel
{
public:
  MotionModel() = default;

  virtual ~MotionModel() = default;

  virtual void predict(models::State & state)
  {
    using namespace xt::placeholders;  // NOLINT
    xt::noalias(xt::view(state.vx, xt::all(), xt::range(1, _))) =
      xt::view(state.cvx, xt::all(), xt::range(0, -1));

    xt::noalias(xt::view(state.wz, xt::all(), xt::range(1, _))) =
      xt::view(state.cwz, xt::all(), xt::range(0, -1));

    if (isHolonomic()) {
      xt::noalias(xt::view(state.vy, xt::all(), xt::range(1, _))) =
        xt::view(state.cvy, xt::all(), xt::range(0, -1));
    }
  }

  virtual bool isHolonomic() = 0;

  virtual void applyConstraints(models::ControlSequence & /*control_sequence*/) {}
};

class AckermannMotionModel : public MotionModel
{
public:
  explicit AckermannMotionModel(ParametersHandler * param_handler, const std::string & name)
  {
    auto getParam = param_handler->getParamGetter(name + ".AckermannConstraints");
    getParam(min_turning_r_, "min_turning_r", 0.2);
  }

  bool isHolonomic() override
  {
    return false;
  }

  void applyConstraints(models::ControlSequence & control_sequence) override
  {
    auto & vx = control_sequence.vx;
    auto & wz = control_sequence.wz;

    auto view = xt::masked_view(wz, xt::fabs(vx) / xt::fabs(wz) < min_turning_r_);
    view = xt::sign(wz) * vx / min_turning_r_;
  }

  float getMinTurningRadius() {return min_turning_r_;}

private:
  float min_turning_r_{0};
};

class DiffDriveMotionModel : public MotionModel
{
public:
  DiffDriveMotionModel() = default;

  bool isHolonomic() override
  {
    return false;
  }
};

class OmniMotionModel : public MotionModel
{
public:
  OmniMotionModel() = default;

  bool isHolonomic() override
  {
    return true;
  }
};

}  // namespace mppi

#endif  // NAV2_MPPI_CONTROLLER__MOTION_MODELS_HPP_