Patent ID: 8161657
Filing Date: 2012-04-24
Classification: G01B

Abstract:
1. A measuring force control apparatus which controls a measuring force that is caused to act on a surface of an object to be measured by pushing the object to be measured with a contact portion of a stylus, comprising: the stylus having the contact portion at a tip end, the contact portion being to be contacted with the object to be measured; a stylus holder configured to hold the stylus in a state that the stylus can rotate about a fulcrum member as a fulcrum; a rotation angle detecting module configured to detect a rotation angle of the stylus; an electromagnetic driving module configured to apply a rotation force about the fulcrum to the stylus in accordance with an energization amount; and a controlling module configured to control the energization amount which is to be given to the electromagnetic driving module, wherein the controlling module has: a target rotation angle issuing portion configured to set a target rotation angle of the stylus, an energization amount determining portion configured to obtain a difference between the detected rotation angle of the stylus and the target rotation angle, and to determine the energization amount which is to be given to the electromagnetic driving module so that the difference becomes zero, a limitation value issuing portion configured to set a limitation value for making constant the energization amount which is to be given to the electromagnetic driving module, and an energization amount limiting portion configured to, when the difference between the detected rotation angle of the stylus and the target rotation angle is equal to or larger than a certain angle, limit the energization amount that is determined by the energization amount determining portion, to the limitation value, thereby causing a constant measuring force to be produced.