Stability Analysis Based on Energy Balance of Motion of the Gyroscopic Exercise Tool

This paper deals with the motion of a gyroscopic exercise tool called as the ‘Power Ball’. This gyroscopic exercise tool, which is used to train the hand muscles utilizes a gyroscopic effect caused by a whirling motion of a high speed rotating body. When the input motion is applied to the outer casing, the internal rotor spins at thousands of rpm whirling with a slow precession motion. This paper shows the dynamic model of this tool considering the contact/separation conditions and the sliding motion between the rotor and the case. Two kinds of motion are observed in a numerical simulation. In this paper, stability analysis of motion of the tool is carried out based on the energy balance between the input and output energy in the tool.