  In this paper, we introduce dynamics factor graphs as a graphical framework
to solve dynamics problems and kinodynamic motion planning problems with full
consideration of whole-body dynamics and contacts. A factor graph
representation of dynamics problems provides an insightful visualization of
their mathematical structure and can be used in conjunction with sparse
nonlinear optimizers to solve challenging, high-dimensional optimization
problems in robotics. We can easily formulate kinodynamic motion planning as a
trajectory optimization problem with factor graphs. We demonstrate the
flexibility and descriptive power of dynamics factor graphs by applying them to
control various dynamical systems, ranging from a simple cart pole to a 12-DoF
quadrupedal robot.
