odometry.cpp

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/*
* Author: Luca Marchionni
* Author: Bence Magyar
* Author: Enrique Fernández
* Author: Paul Mathieu
* 
* Author: Braden McDorman (Semio AI, Inc.)
*/
 
#include <quori_holonomic_drive_controller/odometry.hpp>
 
#include <boost/bind.hpp>
 
using namespace quori_holonomic_drive_controller;
 
namespace bacc = boost::accumulators;
 
Odometry::Odometry(size_t velocity_rolling_window_size)
: timestamp_(0.0)
, x_(0.0)
, y_(0.0)
, heading_(0.0)
, linear_(0.0)
, angular_(0.0)
, wheel_separation_(0.0)
, left_wheel_radius_(0.0)
, right_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))
{
}
 
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  * left_wheel_radius_;
  const double right_wheel_cur_pos = right_pos * right_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 = (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 left_wheel_radius, double right_wheel_radius)
{
  wheel_separation_   = wheel_separation;
  left_wheel_radius_  = left_wheel_radius;
  right_wheel_radius_ = right_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_);
}