A hazard analysis system for robotic work cells

Abstract

Robotic work cells have proliferated in recent years, but safety guidance in the area of safety sensing devices has not kept pace. This article presents a hazard analysis technique to be used as a tool to evaluate and improve the safety of existing or new robot workstations. It is based upon a study of robot safety practices in industry. The hazard analysis was developed by first identifying robot-related hazard factors: person–machine communication, the work environment, and decision making. Next, operational modes were specified to isolate types of worker intrusion into the work space. In addition, the study defined four robot sensor zones on the perimeter, inside the work zone, on the robot, and on the worker. Finally, a complete description of expected robot safety responses was created by combining operational modes and sensor zones into a matrix. Using these tools, the hazard analysis was compiled to address infractions of sound safety practices, intrusion into robot work zones, inadvertent operation while in an unsafe mode, and unplanned robot movement. © 1998 John Wiley & Sons, Inc.