Microscopic positioning device and tool position/orientation compensating method

• US 20040244208A1
• Filed: 05/26/2004
• Published: 12/09/2004
• Est. Priority Date: 06/05/2003
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Sakaida, Yasuhiro, Ebihara, Kenzo, Sawada, Kiyoshi
• Granted Patent: US 6,920,696 B2
• Time in Patent Office: Days
• US Class Current: 33/1M
• CPC Class Codes: H02N 2/0095 producing combined linear and rotary motion, e.g. multi-direction positioners
• CPC Class Codes: Y10S 977/837 Piezoelectric property of nanomaterial
• CPC Class Codes: Y10S 977/872 Positioner

Abstract

A microscopic positioning device having machine rigidity and being capable of achieving nano-order positioning accuracy and a method of compensating tool position and orientation. A driving unit comprises two piezoelectric elements P1 and P2 arranged into alignment along an expanding/shrinking direction. Both ends of the piezoelectric element P1, facing in the expanding/shrinking direction, are fixed to a base member and a movable member, respectively. The other piezoelectric element P2 is fixed to the base member only at one end. A gap L is formed between the piezoelectric element P2 and the movable member. Where expanding displacement amounts of the piezoelectric elements P1 and P2 are a1 and a2, respectively, voltage applied to the piezoelectric elements P1 and P2 is so controlled to satisfy an equation, a1 a2=a≧L. It is possible to position the movable member at a position within a maximum stroke a in the nano-order. The driving units may be arranged in the orthogonal directions, thereby providing the positioning device with two degrees of freedom, and further providing six degrees of freedom including rotation axes.

Claims

1. A microscopic positioning device comprising:

a base member having first and second abutting faces;

a movable member having first and second abutting faces; and

at least one driving unit for driving said movable member to be positioned with respect to said base member, including a first piezoelectric element and a second piezoelectric element arranged along a straight line on which expanding/shrinking directions thereof are aligned, one end and the other end of said first piezoelectric element in the expanding/shrinking direction being fixed to the first abutting faces of said base member and said movable member, respectively, and one end of said second piezoelectric element in the expanding/shrinking direction being fixed to one of the second abutting faces of said base member and said movable member, and the other end of said second piezoelectric element being confronting the other of the second abutting faces of said base member and said movable member with a gap in between in unenergized states of said first and second piezoelectric elements.

2. A microscopic positioning device according to claim 1, wherein one or more driving units are provided for one of perpendicular directions such that the straight lines on which the expanding/shrinking directions of the piezoelectric elements of respective driving units are aligned extend perpendicular to each other, so that said movable member is driven with respect to said base member in the perpendicular directions.

3. A microscopic positioning device according to claim 1, wherein four driving units are provided along four sides of a rectangle to drive and position a single movable member with respect to a single base member.

4. A microscopic positioning device according to claim 3, further comprising an additional piezoelectric element disposed at each of four corners of the rectangle, wherein an expanding/shrinking direction of the additional piezoelectric element extends in a direction perpendicular to a plane of the rectangle, and one end and the other end of said additional piezoelectric element are fixed to said base member and said movable member, respectively.

5. A microscopic positioning device according to claim 1, further comprising a micrometer for performing a coarse positioning of said base member along a coarse adjustment axis in the same direction as the expanding/shrinking directions of the piezoelectric elements of at least one of said driving units.

6. A method of compensating a position and/or an orientation of a blade edge of a tool in a nano-order using a microscopic positioning device comprising:

a base member having first and second abutting faces;

a movable member having first and second abutting faces;

at least one driving unit for driving said movable member to be positioned with respect to said base member, including a first piezoelectric element and a second piezoelectric element arranged along a straight line on which expanding/shrinking directions thereof are aligned, one end and the other end of said first piezoelectric element in the expanding/shrinking direction being fixed to the first abutting faces of said base member and said movable member, respectively, and one end of said second piezoelectric element in the expanding/shrinking direction being fixed to one of the second abutting faces of said base member and said movable member, and the other end of said second piezoelectric element being confronting the other of the second abutting faces of said base member and said movable member with a predetermined gap in between in unenergized states of said first and second piezoelectric elements.