An access detection and machine cycle tracking system for machine safety

The high number of occupational accidents occurring every year in the industrial sector is still one of the main social policy action areas of governments worldwide. Both technical and human failures are often addressed as the main causes for accidents at work. However, the lack of full hazard prevention effectiveness from currently available Safeguarding Devices is another factor that should be considered, at least, from an engineering viewpoint. This paper presents a recently patented Access Detection and Machine Cycle Tracking System (ADMCTS) for industrial machinery with active safety purposes. Active safety paradigm has greatly succeeded in the automotive sector in the last years, dramatically improving road traffic accident prevention by means of active devices with real-time capabilities. Based on a dedicated Computer Vision System (CVS) for real-time video analysis of a monitored safety zone, the ADMCTS performs three main functions: access and presence detection of objects entering and/or remaining within the monitored zone, machine cycle tracking, and warning and alarm signal handling to ensure that machine functions are only allowed when workplace conditions are safe. Machine cycle tracking provides the ADMCTS with an adaptive risk assessment capability for optimal prevention. In order to provide a thoughtful description of its functionality, a state machine model of the ADMCTS is introduced, and a visual walk-through of this model, as applied on a generic cutting machine, is also discussed.