Modeling of a flexible arm used in a hammering robot and its application

When a robot hits an object by a hammer, the robot manipulator has to absorb an impulsive reaction with the motor of a joint or a link of the arm, in oder to protect the robot and the object from the breakdowns. This paper proposes a hammer system which is composed of a weight for the head and a flexible arm for the handle of a hammer, in order to realize a hammering robot. The use of a flexible arm has the advantage that the flexibility can absorb the reaction at a hitting easily. After the hitting, however, the hammer system vibrates complicatedly due to the moment of inertia of the head of a hammer. Therefore the modes of vibrations are analyzed by taking it into consideration. And the mathematical model of the hammer system, which is forced by not only a driving torque at a hub fixing one end of the flexible arm but also the reaction at the head of the hammer, is formulated by the Hamilton's principle. Last it is shown that the intensity and direction of the reaction are measured by using the model.

hammering robot

flexible arm

impulsive reaction

modal analysis