gazebo_imu_plugin.h

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/*
 * Copyright 2015 Fadri Furrer, ASL, ETH Zurich, Switzerland
 * Copyright 2015 Michael Burri, ASL, ETH Zurich, Switzerland
 * Copyright 2015 Mina Kamel, ASL, ETH Zurich, Switzerland
 * Copyright 2015 Janosch Nikolic, ASL, ETH Zurich, Switzerland
 * Copyright 2015 Markus Achtelik, ASL, ETH Zurich, Switzerland
 * Copyright 2016 Geoffrey Hunter <gbmhunter@gmail.com>
 *
 * 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 ROTORS_GAZEBO_PLUGINS_IMU_PLUGIN_H
#define ROTORS_GAZEBO_PLUGINS_IMU_PLUGIN_H

#include <random>

#include <Eigen/Core>
#include <gazebo/common/common.hh>
#include <gazebo/common/Plugin.hh>
#include <gazebo/gazebo.hh>
#include <gazebo/physics/physics.hh>

#include "Imu.pb.h"

#include "rotors_gazebo_plugins/common.h"

namespace gazebo {

// Default values for use with ADIS16448 IMU
static constexpr double kDefaultAdisGyroscopeNoiseDensity =
    2.0 * 35.0 / 3600.0 / 180.0 * M_PI;
static constexpr double kDefaultAdisGyroscopeRandomWalk =
    2.0 * 4.0 / 3600.0 / 180.0 * M_PI;
static constexpr double kDefaultAdisGyroscopeBiasCorrelationTime =
    1.0e+3;
static constexpr double kDefaultAdisGyroscopeTurnOnBiasSigma =
    0.5 / 180.0 * M_PI;
static constexpr double kDefaultAdisAccelerometerNoiseDensity =
    2.0 * 2.0e-3;
static constexpr double kDefaultAdisAccelerometerRandomWalk =
    2.0 * 3.0e-3;
static constexpr double kDefaultAdisAccelerometerBiasCorrelationTime =
    300.0;
static constexpr double kDefaultAdisAccelerometerTurnOnBiasSigma =
    20.0e-3 * 9.8;
// Earth's gravity in Zurich (lat=+47.3667degN, lon=+8.5500degE, h=+500m, WGS84)
static constexpr double kDefaultGravityMagnitude = 9.8068;

// A description of the parameters:
// https://github.com/ethz-asl/kalibr/wiki/IMU-Noise-Model-and-Intrinsics
// TODO(burrimi): Should I have a minimalistic description of the params here?
struct ImuParameters {
  double gyroscope_noise_density;
  double gyroscope_random_walk;
  double gyroscope_bias_correlation_time;
  double gyroscope_turn_on_bias_sigma;
  double accelerometer_noise_density;
  double accelerometer_random_walk;
  double accelerometer_bias_correlation_time;
  double accelerometer_turn_on_bias_sigma;
  double gravity_magnitude;

  ImuParameters()
      : gyroscope_noise_density(kDefaultAdisGyroscopeNoiseDensity),
        gyroscope_random_walk(kDefaultAdisGyroscopeRandomWalk),
        gyroscope_bias_correlation_time(
            kDefaultAdisGyroscopeBiasCorrelationTime),
        gyroscope_turn_on_bias_sigma(kDefaultAdisGyroscopeTurnOnBiasSigma),
        accelerometer_noise_density(kDefaultAdisAccelerometerNoiseDensity),
        accelerometer_random_walk(kDefaultAdisAccelerometerRandomWalk),
        accelerometer_bias_correlation_time(
            kDefaultAdisAccelerometerBiasCorrelationTime),
        accelerometer_turn_on_bias_sigma(
            kDefaultAdisAccelerometerTurnOnBiasSigma),
        gravity_magnitude(kDefaultGravityMagnitude) {}
};

class GazeboImuPlugin : public ModelPlugin {
 public:

  GazeboImuPlugin();
  ~GazeboImuPlugin();

  void InitializeParams();
  void Publish();

 protected:
  void Load(physics::ModelPtr _model, sdf::ElementPtr _sdf);

  void AddNoise(
      Eigen::Vector3d* linear_acceleration,
      Eigen::Vector3d* angular_velocity,
      const double dt);

  void OnUpdate(const common::UpdateInfo&);

 private:

  bool pubs_and_subs_created_;

  void CreatePubsAndSubs();


  std::string namespace_;
  std::string imu_topic_;

  transport::NodePtr node_handle_;

  transport::PublisherPtr imu_pub_;

  std::string frame_id_;
  std::string link_name_;

  std::default_random_engine random_generator_;
  std::normal_distribution<double> standard_normal_distribution_;

  physics::WorldPtr world_;

  physics::ModelPtr model_;

  physics::LinkPtr link_;

  event::ConnectionPtr updateConnection_;

  common::Time last_time_;

  //            and then published onto a topic
  gz_sensor_msgs::Imu imu_message_;

  ignition::math::Vector3d gravity_W_;
  ignition::math::Vector3d velocity_prev_W_;

  Eigen::Vector3d gyroscope_bias_;
  Eigen::Vector3d accelerometer_bias_;

  Eigen::Vector3d gyroscope_turn_on_bias_;
  Eigen::Vector3d accelerometer_turn_on_bias_;

  ImuParameters imu_parameters_;
};

}  // namespace gazebo

#endif // ROTORS_GAZEBO_PLUGINS_IMU_PLUGIN_H