Development of the Absolute Type Magnetic Encoder Suitable for Thinner Structure

Rotary encoders are often used as position detectors in robot control systems and are of two types: optical encoders and magnetic encoders. Magnetic rotary encoders have attracted attention for their durability in unclean environments, reliability at low temperatures, excellent shock resistance, and wide variety of designs. Such encoders can function in two different ways; detecting either relative or absolute positions. In this paper, an absolute position-detecting magnetic encoder with high resolution and a thin construction is proposed, and such an encoder (100 mm dia. × 20 mm) with 11 bits, only one-fourth as thick as conventional magnetic encoders, has been trial-fabricated.