JPS5782707A - Method and device for measuring curved surface shape - Google Patents

Abstract

PURPOSE:To reduce the size of a measuring head and to improve the follow-up characteristics of a measurer by supporting the measurer movably at right angles to the movement direction of the measuring head, by detecting the extent of displacement by moving the measuring head by a certain extent after the measurer comes into contact with a surface to be measured, and by calculating the position of the surface to be measured. CONSTITUTION:With pulses from an arithmetic processor 50, a driving circuit DUZ drives a servomotor SMZ to bring a measurer 15 into contact with a surface Wa to be measured, and a rotation control circuit 40 turns the measurer 15 through detectors 25a-25b and 26a-26b so that it is in positive-gradient contact with the surface Wa. The processor 50 drives the motor SMZ until the output of a displacement detector 41 shows zero, and stores the output Zi of a detection counter 45 in a 51. Then, the processor 50 moves the measurer 15 along the surface Wa to calculate its surface position from the output (extent of backward movement of measurer 15) Li of the position detecting circuit 41, the radius of the tip of the measurer 15 which is stored 51, and the angle of the axis of the measurer 15 to Z axis. Consequently, the size of a measuring head is reduced and the follow-up characteristics of the measurer are improved.