odometry.cpp

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/*
 * Author: Luca Marchionni
 * Author: Bence Magyar
 * Author: Enrique Fernández
 * Author: Paul Mathieu
 */

#include <robotican_controllers/odometry.h>

#include <boost/bind.hpp>

namespace diff_drive_controller
{
    namespace bacc = boost::accumulators;

    Odometry::Odometry(size_t velocity_rolling_window_size, double slipFactor)
            : timestamp_(0.0)
            , x_(0.0)
            , y_(0.0)
            , heading_(0.0)
            , linear_(0.0)
            , angular_(0.0)
            , wheel_separation_(0.0)
            , wheel_radius_(0.0)
            , left_wheel_old_pos_(0.0)
            , right_wheel_old_pos_(0.0)
            , velocity_rolling_window_size_(velocity_rolling_window_size)
            , linear_acc_(RollingWindow::window_size = velocity_rolling_window_size)
            , angular_acc_(RollingWindow::window_size = velocity_rolling_window_size)
            , integrate_fun_(boost::bind(&Odometry::integrateExact, this, _1, _2))
    {
      _slipFactor = slipFactor;
    }

    void Odometry::init(const ros::Time& time)
    {
      // Reset accumulators and timestamp:
      resetAccumulators();
      timestamp_ = time;
    }

    bool Odometry::update(double left_pos, double right_pos, const ros::Time &time)
    {
      const double left_wheel_cur_pos  = left_pos  * wheel_radius_;
      const double right_wheel_cur_pos = right_pos * wheel_radius_;

      const double left_wheel_est_vel  = left_wheel_cur_pos  - left_wheel_old_pos_;
      const double right_wheel_est_vel = right_wheel_cur_pos - right_wheel_old_pos_;

      left_wheel_old_pos_  = left_wheel_cur_pos;
      right_wheel_old_pos_ = right_wheel_cur_pos;

      const double linear  = (right_wheel_est_vel + left_wheel_est_vel) * 0.5 ;
      const double angular = _slipFactor*((right_wheel_est_vel - left_wheel_est_vel) / wheel_separation_);

      integrate_fun_(linear, (angular));

      const double dt = (time - timestamp_).toSec();
      if (dt < 0.0001)
        return false; // Interval too small to integrate with

      timestamp_ = time;

      linear_acc_(linear/dt);
      angular_acc_(angular/dt);

      linear_ = bacc::rolling_mean(linear_acc_);
      angular_ = bacc::rolling_mean(angular_acc_);

      return true;
    }

    void Odometry::updateOpenLoop(double linear, double angular, const ros::Time &time)
    {
      linear_ = linear;
      angular_ = angular;

      const double dt = (time - timestamp_).toSec();
      timestamp_ = time;
      integrate_fun_(linear * dt, angular * dt);
    }

    void Odometry::setWheelParams(double wheel_separation, double wheel_radius)
    {
      wheel_separation_ = wheel_separation;
      wheel_radius_     = wheel_radius;
    }

    void Odometry::setVelocityRollingWindowSize(size_t velocity_rolling_window_size)
    {
      velocity_rolling_window_size_ = velocity_rolling_window_size;

      resetAccumulators();
    }

    void Odometry::integrateRungeKutta2(double linear, double angular)
    {
      const double direction = heading_ + angular * 0.5;

      x_       += linear * cos(direction);
      y_       += linear * sin(direction);
      heading_ += angular;
    }

    void Odometry::integrateExact(double linear, double angular)
    {
      if (fabs(angular) < 1e-6)
        integrateRungeKutta2(linear, angular);
      else
      {
        const double heading_old = heading_;
        const double r = linear/angular;
        heading_ += angular;
        x_       +=  r * (sin(heading_) - sin(heading_old));
        y_       += -r * (cos(heading_) - cos(heading_old));
      }
    }

    void Odometry::resetAccumulators()
    {
      linear_acc_ = RollingMeanAcc(RollingWindow::window_size = velocity_rolling_window_size_);
      angular_acc_ = RollingMeanAcc(RollingWindow::window_size = velocity_rolling_window_size_);
    }

    void Odometry::setSlipFactor(double slipFactor) {
      _slipFactor = slipFactor;
    }
} // namespace diff_drive_controller