Continuous Hitting by a Robot with a Flexible Link Hammer

Abstract

This paper proposes a continuous hitting by a robot with a flexible link hammer. It is assumed that the hitting makes use of only the first mode in the vibration of the flexible link. The relative displacement of the first mode vibration is expressed as the function of the pulses of an angular acceleration which drives the link. This expression can easily derive two equations for the hitting conditions that the hammer can flap an object with a desired hitting velocity. The generated time and width of the pulses are determined from the equations so that a continuous hitting can be achieved with the minimum energy and hitting cycle. However, the hammer head collides with an object twice in one hitting cycle due to a larger coefficient of rebound between them. Therefore, this problem can be evaded by increasing the number of the pulses.
In experiments an optimal regulator is used in order to suppress the second and the higher modes of the vibration. And a proposed continuous hitting is realized by the mode control of the regulator. As this system utilizes flexibility of the link effectively, it is more excellent than an intermittent hitting because of less energy and shorter hitting cycle.