Contactless signal transmission for industrial bus at rotary joint

In multi-actuator mechatronic and distributed multi-sensor systems, signal transmission plays an important role via rotary joint. Comparing with wireless communication, industrial bus is preferred for real-time signal transmission due to its low latency. However, industrial bus with cables at rotary joint suffers from limit free rotation, frequent maintenance and complex routing. In this paper, a contactless signal transmission (CST) system for industrial bus at rotary joint is proposed. In particular, optical coupling is designed and evaluated via an air gap for rotation motion at rotary joint. Logical strategies are proposed in signal converter for bridging CAN bus with optical signal coupling. For experimental verification, a developed CST system is implemented in a communication with two motor drives via CAN bus.