PURPOSE: To accurately measure an extremely small angle of rotation without using an encoder.
CONSTITUTION: The shaft 2 of a rotary table 1 is supported and borne by a bearing member 3 so as to be freely turned, and the table is turned and driven by a rotational drive means 4 composed of a stepping motor or the like. An angle-of-rotation measuring mechanism used to control the rotary table 1 driven by the rotation and drive means 4 is constituted of a rotary body 10 under test and of a distance measuring device 20. The rotary body 10 under test is shaped as a spur gear shape in which inclined plane parts 11 tilted to the rotation direction at a prescribed angle have been formed in required parts at every definite angle, reflecting plates 12 which have been mirror-finished are attached to, and installed at, the inclined plane parts 11, each position of the reflecting plates 12 is determined by the distance measuring device 20 constituted of a laser length-measuring instrument using a two-beam interference method by a laser beam, and a control signal is input to a controller 5 for the rotation and drive means 4.
HASHIMOTO AKIRA
NAGASAWA KIYOSHI
MURAYAMA TAKESHI
