Measurement of Dimensions Using Robot Constructed Utilizing Optical Fiber Signal Transmission System Having Reference Capability.

Abstract

This paper describes the optical signal transmission system constructed using direct intensity modulation technique which is capable of transmitting a signal through a movable optical fiber, and its application to the measurement of dimensions using a robot. When the optical fiber is bent, the optical power losses are increased, and however, the power loss at 830nm was almost the same as that at 660nm. So, the light at 660nm can be used as a reference light to correct the intensity error of the signal light at 830nm which is caused by the optical fiber bending. This system simultaneously transmits the signal and reference from a transmitter to a receiver through a movable optical fiber. At the receiver, the signal is normallized by the reference to provide the correct output signal. When the optical fiber was bent with a bending radius of 10mm at a bending angle of 180 degrees, the transmission error rate was 0.28 in the conventional single-path system. This error was caused by the bending loss of the signal light power. Under the same bending conditions, the error rate was improved to 0.03 in the proposed system due to the reference capability. This system was experimentally applied to transmit data from the displacement sensor attached to the arm of the robot through the movable optical fiber installed in the arm of the robot. The proposed system having the reference capability can transmit an optical distance signal with the minimum error through a movable optical fiber. The experiment was successful.