Wireless, Battery-free RFID Sensor for Monitoring Machine Tools

Researchers at Fraunhofer IPMS have created a wireless, battery-free RFID sensor that can monitor the temperature and deformations on metallic rotating parts such as shafts or spindles. Prudent operators of highly automated production facilities keep a close eye on the condition of their equipment and machinery. Early identification of faulty processes or premature wear on tools can prevent damage to machines and production losses as well as optimize operational procedures.

Integrating sensors on tool shafts or spindles is not very easy. It takes great effort to integrate cables or batteries on rotating parts, making wireless sensor systems more suitable. RFID sensors are included among such wireless sensor systems. RFID technology enables the wireless transfer of data and energy to the sensor via a reader device. The reader energizes the sensor in order to conduct measurement and transmit resulting data. Anyone familiar with RFID Auto-ID technology knows that wireless transmission of data from the sensor transponder to the reader poses a particular challenge in metallic environments, in that metal partially reflects electromagnetic waves to unintentionally hinder enough energy from reaching the sensor. The researchers were able to compensate for this effect with a special antenna geometry. They also adapted the sensor transponder to the structural shape of the shaft.

Intelligent software solutions make it easier to integrate into existing production environments and connect to existing control systems. The successful introduction of wireless RFID-sensor systems very often requires comprehensive knowledge of ASIC and antenna design ranging from sensor-tag development to sensor, system, and cloud integration. The RFID-OPC-UA-AutoID-Server (ROAD-Server) middleware implements the OPC-UA AutoID companion specification relevant to RFID-sensor components to provide manufacturer-independent, standard-compliant communication for industrial automation. This allows for any reader device, identification-, or sensor-transponders from any manufacturer and operating in any of the different LF, HF, UHF and NFC frequencies to be uniformly addressed.

Interested parties can view Fraunhofer IPMS RFID-sensor modules at this year's RFID Journal LIVE!, the world's largest conference and exhibition for RFID technology being held in Orlando, USA from April 10-12, 2018. Fraunhofer IPMS experts will present sample systems equipped with various sensors and give advice on the implementation of RFID sensor systems.