US 4,979,127 A · Method for automatically setting a tool tip point

Abstract

An automatic setting method is provided, in which the position of a tool tip point in a coordinate system set for a faceplate of a robot, can be set easily and accurately. The robot is caused to assume different postures while maintaining the tool tip point of a tool (2) at one point (4) within a space in which the robot is installed. Four or more coordinate positions of a faceplate center point (3) corresponding to the individual postures of the robot are given for instruction. Subsequently, a spherical surface (5) passing through these instruction positions is determined by the method of least squares, and the position of the tool tip point in the faceplate coordinate system is calculated and set on the basis of a calculated value of the position of the center of curvature of the spherical surface, the individual instruction coordinate positions, and tool posture vectors.

Claims8

Dependent claims

A method for automatically setting a tip point of a tool, comprising the steps of:

(a) causing a robot, having an aim with a faceplate containing a center, to assume at least four postures while maintaining the tip point of the tool on a fixed point within a space occupied by said robot and instructing said robot of coordinate positions of the center point of the faceplate of said robot, using a base coordinate system set in the space occupied by said robot, corresponding to the at least four postures;
(b) calculating coordinates of a center of curvature of a spherical surface passing approximately through the coordinate positions instructed in step (a) for the center point of the faceplate in dependence upon the coordinate positions;
and
(c) determining and setting a coordinate position of the tip point, in a faceplate coordinate system for the faceplate, in dependence upon posture vectors of the tool, the coordinates of the center of curvature of the spherical surface calculated in step (b), and at least one of the coordinate positions of the center point of the faceplate given for instruction in step (a).

1 more element

A method for obtaining position information of a tool tip relative to a faceplate of a robot arm, comprising the steps of:

(a) positioning the robot arm in at least four different postures while maintaining the tool tip at a fixed point;
(b) detecting origin point coordinates of the faceplate in a robot coordinate system in each of the at least four different postures;
(c) defining a spherical surface, having a radius and a center of curvature with coordinates in the robot coordinate system, such that the origin point coordinates of the faceplate detected in step (b) lie approximately on the spherical surface;
and
(d) determining a coordinate position of the tool tip in a faceplate coordinate system in dependence upon the radius and the coordinates of the center of curvature of the spherical surface defined in step (c) and the origin point coordinates of the faceplate corresponding to at least one of the at least four different postures.

2 more elements

Dependencies are inferred from the claim text.

Method for automatically setting a tool tip point

Life of this patent

Method for automatically setting a tool tip point

Life of this patent

Abstract

Claims8