Abstract
When periodic external force is inputted to van der Pol equation, its self-excitation vibration is suppressed, and its oscillatory frequency synchronizes with frequency of the external force. This behavior is called forced entrainment. We proposed periodic input control method that can control energy of system using forced entrainment, and controlled periodic motion of various systems (such as pendulum, quasi passive walking robot and hopping robot). Because a periodic input control system whose energy is controlled by our method, vibrates without external force continuously, it is supposed that the system is a self-excitation vibration system. Therefore, we analyzed structure and characteristics of the system. First, we analyze whether periodic input system has characteristics as self-excitation vibration system. Next, we derive the condition that forced entrainment is caused by periodic external force. Finally, we show the result that inspected validity of our analysis by experiments.
