Control method of an automatic inside-diameter measuring apparatus and an automatic measuring apparatus

A control method of an automatic inside-diameter measuring apparatus, the automatic inside-diameter measuring apparatus comprising:

• an inside-diameter measuring part including a contact point configured to move forward and backward in a direction perpendicular to a cylinder axis of a cylinder case, an electric driver configured to move the contact point forward and backward, and a displacement detector configured to detect displacement of the contact point;
• a driver for relatively moving the inside-diameter measuring part with respect to an object to be measured to insert and retract the inside-diameter measuring part into and from a hole to be measured;
• and
• a controller configured to control operation of the inside-diameter measuring part and the driver, the control method comprising:
• inserting, by the driver, the inside-diameter measuring part into the hole to be measured;
• bringing the contact point into contact with an inner wall of the hole to measure an inside diameter of the hole;
• and
• retracting the inside-diameter measuring part from the hole by the driver, wherein:
• the automatic inside-diameter measuring apparatus further includes:
• a support frame configured to support the inside-diameter measuring part and to couple the inside-diameter measuring part to the driver;
• and
• a floating joint interposed between the support frame and the inside-diameter measuring part to allow relative translation and rotation of the inside-diameter measuring part with respect to the support frame;
• the inserting includes temporarily stopping drive of the driver after the inside-diameter measuring part is inserted by the driver into the hole to be measured, and
• the bringing the contact point into contact includes autonomously adjusting, by the inside-diameter measuring part, a position and posture of the inside-diameter measuring part itself to align the cylinder axis of the cylinder case with an axis of the hole to be measured while the inside-diameter measuring part is relatively displaced with respect to the support frame by a reaction force applied to the inside-diameter measuring part from the inner wall of the hole to be measured when the electric driver moves the contact point forward and brings the contact point into contact with the inner wall of the hole to be measured.