Device for measuring the shape of a three-dimensional object

• US 4,703,443 A
• Filed: 02/07/1985
• Issued: 10/27/1987
• Est. Priority Date: 02/16/1984
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Moriyasu, Takashi
• Primary Examiner(s): Krass, Errol A.
• Assistant Examiner(s): Teska, Kevin J.
• Application Number:
  US06/699,133
• Time in Patent Office: 992 Days
• Field of Search: 364/168, 364/518, 364/522, 364/559, 364/513, 364/569, 364/474, 33/1 M, 33/1 N, 33/169 R, 33/503, 901/10, 901/14, 901/15
• US Class Current: 702/168
• CPC Class Codes: B25J 17/0275 Universal joints, e.g. Hooke, Cardan, ball joints
• CPC Class Codes: B25J 9/00 Programme-controlled manipulators
• CPC Class Codes: B25J 9/04 by rotating at least one arm, excluding the head movement itself, e.g. cylindrical coordinate type or polar coordinate type
• CPC Class Codes: G01B 7/004 for measuring coordinates of points
• CPC Class Codes: G01B 7/28 for measuring contours or curvatures

Abstract

A device for measuring the shape of a three-dimensional object comprises a movable arm composed of a plurality of movable arm members and a probe coupled to a forward end of the movable arm by a universal joint. At each of the movable arm members and probe, there is provided an angle-of-rotation encoder for detecting the angle of rotation. In order to measure the shape of the three-dimensional object with a lesser number of measuring times, the probe has a flat surface portion at its forward end which contacts the object. A calculating section calculates the direction of the flat surface portion of the probe in contact with the object, on the basis of the information from the angle-of-rotation encoders and the known information on dimensions of the movable arm, to thereby determine a tangent plane of the object at a contact point between the flat surface portion and the object, and determines the shape of the object from a plurality of tangent planes at the contact points.

Claims

1. A device for measuring the shape of a three-dimensional object comprising:

a movable arm having a plurality of movable arm members coupled in tandem by joints;

a probe coupled to the forward end of said movable arm by a universal joint, said probe adapted for contacting the three-dimensional object, the shape of which is to be measured, and said probe being rotatable and having at its forward end a flat surface portion which is provided perpendicular to an axis of said probe and which contacts said three-dimensional object;

angle-of-rotation encoder means for detecting the angles of rotation of said probe and said movable arm members during the measurement of the shape of the three-dimensional object; and

calculating means for calculating, on the basis of information from said angle-of-rotation encoder means and the dimensions of said movable arm, the orientation of said flat surface portion of said probe in contact with the three-dimensional object, to thereby determine a tangent plane at the contact point between said flat surface portion and said three-dimensional object, and determining the shape of the three-dimensional object from a plurality of tangent planes at contact points between said flat surface portion of said probe and said object.

2. A device for measuring the shape of a three-dimensional object, comprising:

a base on which a three-dimensional object, the shape of which is to be measured, is placed;

a supporting column provided vertically on a plane of said base to be rotatable in the plane of said base;

a movable arm mounted on one end of said supporting column and having a plurality of arm members coupled in tandem by joints, each of said arm members being arranged to be rotatable in a plane perpendicular to the plane of said base;

a probe coupled to a forward end of said movable arm by a universal joint, said probe being rotatable and having a flat surface portion which is provided perpendicular to an axis of said probe and which contacts the three-dimensional object to be measured;

angle-of-rotation encoder means for detecting angles of rotation of said probe, said supporting column, and said movable arm members; and

calculating means for calculating, on the basis of the rotation-angle information from said angle-of-rotation encoder means and the known dimensions of said supporting column, said movable arm and said probe, the orientation of said flat surface portion of said probe contact with the three-dimensional object, to thereby determine a tangent plane at the contact point between said flat surface portion and the three-dimensional object, and for determining the shape of the three-dimensional object from a plurality of tangent planes at contact points between said flat portion and object.

3. A device according to claim 2, in which said probe has a plurality of flat portions, one of said flat portions being selectively used in calculating the tangent plane.

4. A device according to claim 2, in which said flat portion of said probe is circular.

5. A device according to claim 2, in which said flat portion of said probe is star-shaped.

6. A device according to claim 2, in which said calculating means uses a rectangular coordinate system in determining the tangent plane of the three-dimensional object.

7. A device according to claim 2, in which said calculating means uses a cylindrical coordinate system in determining the tangent plane of the three-dimensional object.

8. A device according to claim 2, in which said calculating means uses a polar coordinate system in determining the tangent plane of the three-dimensional object.