Measuring instrument

• US 8,191,408 B2
• Filed: 06/30/2009
• Issued: 06/05/2012
• Est. Priority Date: 07/01/2008
• Status: Active Grant

• Current Assignee: Mitutoyo Corporation
• Original Assignee: Mitutoyo Corporation
• Inventors: Igasaki, Shiro, Yamagata, Masaoki
• Primary Examiner(s): LARKIN, DANIEL SEAN
• Application Number:
  US12/494,954
• Publication Number:
  US 20100000307A1
• Time in Patent Office: 1,071 Days
• Field of Search: 731/05, 335/03, 335/04, 335/51, 335/55, 335/56, 335/59
• US Class Current: 73/105
• CPC Class Codes: G01B 3/008 Arrangements for controlling the measuring force

Abstract

A surface texture measuring instrument includes a contact piece to be in contact with an object, a sensor driving mechanism that moves the contact piece along the surface of the object, a controller that controls the sensor mechanism, and a force sensor that detects a measuring force exerted on the contact piece when the contact piece is brought into contact with the object. The controller includes a target value output that outputs a target value of the measuring force, a feedback controller that performs feedback control of the sensor driving mechanism based on a deviation between the measuring force and the target value, and a feedback compensator provided on the feedback controller. The feedback compensator performs feedback compensation in accordance with the measuring force.

Claims

1. A measuring instrument comprising:

a contact piece to be in contact with an object;

a moving mechanism that moves the contact piece along a surface of the object;

a controller that controls the moving mechanism; and

a measuring force detector that detects a measuring force exerted on the contact piece when the contact piece is brought into contact with the object, wherein

the controller includes;

a target value output that outputs a target value of the measuring force;

a feedback controller that performs feedback control of the moving mechanism; and

a feedback compensator provided on the feedback controller, the feedback compensator adjusting the measuring force and outputting a compensation measuring force based on a result of a comparison between the target value and the measuring force, and

the feedback controller performs the feedback control based on a deviation between the target value and the compensation measuring force.

2. The measuring instrument according to claim 1, wherein

the feedback compensator compares the target value with the measuring force and performs the feedback compensation to increase the deviation when the measuring force is equal to or smaller than the target value.

3. The measuring instrument according to claim 2, wherein

the feedback compensator performs the feedback compensation to decrease the deviation when the measuring force is larger than the target value.