抄録
It is necessary to investigate a natural frequency of a flexible link constituting a manipulator in order to control its flexural vibration. The natural frequency of the link is subjected to gravity if its flexibilty is increased.
This paper deals with a natural frequency of a flexible link which is set with an arbitrary angle of elevation. First it is assumed that a vibration superposes on a static deflection due to gravity. The differential equation and the boundary condition of the vibration under gravity are presented. The differential equation is related to a concentrated mass at the tip of the link and a distributed mass of the link. And it is shown that the boundary condition is a function of the angle of an elevation θ and a static deflection γs at the tip of the link. Second some frequency equations are derived by simplifying the differential equation, and the natural frequencies of the first mode are calculated. These frequencies are compared with experimental values. It is shown from the experiments that the natural frequencies are influenced by an angle (θ+γs) of the tip of a link and a distributed mass has to be taken into consideration.
