Abstract
In recent years, industrial robots have been introduced to various production sites through teaching playback, enabling more efficient assembly lines and welding lines for large workpieces in automotive and other industries. Furthermore, offline programming is expected to be utilized for cutting workpieces that are becoming even larger in the next-generation EV giga-cast and construction industries. However, the machining accuracy of robots, in terms of motion accuracy, is lower than that of machine tools, and their low rigidity causes vibration. Therefore, in this study, we attempt to construct a system for the practical cutting of large workpieces by attaching a DC brushless motor controlled by a single-board computer and drill to the end-effector of a large industrial robot and examining the basic characteristics of this system. The relationship between the rotational speed and duty ratio of the pulse width modulation voltage is clarified, and the range where the rotation speed is stable is found such that any rotation speed can be output. It is also clarified that the mechanical time constant of the rotational speed of the motor changes when the temperature of the motor spindle changes.
