Teruyuki Izumi

Teachingless grinding robot depending on three force information

When an industrial robot grinds a curved surface of a workpiece, an operator must teach the robot the contour of the surface accurately. This instruction, however, is a very troublesome job because of the large number of teaching points. This paper proposes a grinding robot that requires no teaching. The robot system consists of a manipulator mounted on a cylindrical grinding wheel on the end effector, instruments to measure the three different forces and a computer equipped with an A/D converter. The force information consists of the grinding torque and the two components of the grinding force which is applied to the grinding wheel from the workpiece. The coordinates of the points where the wheel contacts the workpiece are calculated from the force information by the computer. Therefore, the robot is able to recognize the contour of the workpiece and to grind it without teaching. Experiments using an articulated robot arm with five degrees of freedom show that the proposed robot system is applicable to t...

A method of measuring grinding points for a self-teaching grinding robot

It is a very time-consuming task to teach a grinding robot the contour of a workpiece accurately. Therefore, we have proposed a self-teaching grinding robot. This robot system measures three moments which are produced by the grinding force at the wrist of a manipulator, calculates the grinding points on a cylindrical grinding wheel, and recognizes the contour of the workpiece. In order to develop this technique practically, we have studied the determination of grinding points on grinding wheels of various shapes. The results of the analysis and experiments indicate the following: (1) If the shape of the grinding wheel is known and is invariant without wearing away, the grinding points can be calculated from only three components of the moment produced by the grinding force. (2) The calculation is, however, very difficult when the radius of the grinding wheel is not a linear function of the distance along the rotational axis of the wheel. Therefore, one component of the thrust has to be detected to simplif...