Pony II Robot: Inertially Actuated Baton With Double-Action Pendulums

In this paper, we present a robotic locomotor with inertia-based actuation. The goal of this system is to generate various gait modes of a baton, consisting of two masses connected with a massless rod. First, a model for a baton prototype called Pony II is presented. This model incorporates the double-action inertial actuation generated by two rotating pendulums, spinning at constant angular velocities in opposite directions. This system allows regulation of the inertial forces generated by the spinning masses. In addition, it provides control over the orientation of the resultant inertial force. Numerical simulations of four stable gaits are presented: dragging, tapping, galloping, and hopping. We also developed an experimental prototype, called Pony II, consisting of the double-action actuators. The robot successfully generates all the simulated gaits. In addition, we show that the robot is capable of generating progression on low friction surfaces.