gtsam/examples/OdometryExample.cpp

76 lines
2.5 KiB
C++

/* ----------------------------------------------------------------------------
* GTSAM Copyright 2010, Georgia Tech Research Corporation,
* Atlanta, Georgia 30332-0415
* All Rights Reserved
* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
* See LICENSE for the license information
* -------------------------------------------------------------------------- */
/**
* @file OdometryExample.cpp
* @brief Simple robot motion example, with prior and two odometry measurements
* @author Frank Dellaert
*/
// pull in the 2D PoseSLAM domain with all typedefs and helper functions defined
#include <gtsam/slam/pose2SLAM.h>
// include this for marginals
#include <gtsam/nonlinear/Marginals.h>
#include <iomanip>
#include <iostream>
using namespace std;
using namespace gtsam;
/**
* Example of a simple 2D localization example
* - Robot poses are facing along the X axis (horizontal, to the right in 2D)
* - The robot moves 2 meters each step
* - We have full odometry between poses
*/
int main(int argc, char** argv) {
// create the graph (defined in pose2SLAM.h, derived from NonlinearFactorGraph)
pose2SLAM::Graph graph;
// add a Gaussian prior on pose x_1
Pose2 priorMean(0.0, 0.0, 0.0); // prior mean is at origin
SharedDiagonal priorNoise(Vector_(3, 0.3, 0.3, 0.1)); // 30cm std on x,y, 0.1 rad on theta
graph.addPrior(1, priorMean, priorNoise); // add directly to graph
// add two odometry factors
Pose2 odometry(2.0, 0.0, 0.0); // create a measurement for both factors (the same in this case)
SharedDiagonal odometryNoise(Vector_(3, 0.2, 0.2, 0.1)); // 20cm std on x,y, 0.1 rad on theta
graph.addOdometry(1, 2, odometry, odometryNoise);
graph.addOdometry(2, 3, odometry, odometryNoise);
// print
graph.print("\nFactor graph:\n");
// create (deliberatly inaccurate) initial estimate
pose2SLAM::Values initialEstimate;
initialEstimate.insertPose(1, Pose2(0.5, 0.0, 0.2));
initialEstimate.insertPose(2, Pose2(2.3, 0.1, -0.2));
initialEstimate.insertPose(3, Pose2(4.1, 0.1, 0.1));
initialEstimate.print("\nInitial estimate:\n ");
// optimize using Levenberg-Marquardt optimization with an ordering from colamd
pose2SLAM::Values result = graph.optimize(initialEstimate);
result.print("\nFinal result:\n ");
// Query the marginals
cout.precision(2);
Marginals marginals = graph.marginals(result);
cout << "\nP1:\n" << marginals.marginalCovariance(1) << endl;
cout << "\nP2:\n" << marginals.marginalCovariance(2) << endl;
cout << "\nP3:\n" << marginals.marginalCovariance(3) << endl;
return 0;
}