  In this paper, we present a sequential motion planning and control method for
generating somersaults on bipedal robots. The somersault (backflip or
frontflip) is considered as a coupling between an axile hopping motion and a
rotational motion about the center of mass of the robot; these are encoded by a
hopping Spring-loaded Inverted Pendulum (SLIP) model and the rotation of a
Flywheel, respectively. We thus present the Flywheel SLIP model for generating
the desired motion on the ground phase. In the flight phase, we present a
momentum transmission method to adjust the orientation of the lower body based
on the conservation of the centroidal momentum. The generated motion plans are
realized on the full-dimensional robot via momentum-included task space
control. Finally, the proposed method is implemented on a modified version of
the bipedal robot Cassie in simulation wherein multiple somersault motions are
generated.
