In November 2016, a Chinese firm was showing off its educational toy robot, “Little Chubby,” at the China International Hi-Tech Fair in Shenzhen, China. Without warning, the robot rolled out of control, smashed a glass booth, and injured the man inside. Social media had a field day: the robots were rising at last!
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It’s a common enough trope in science fiction: the robots, having begun their existence as servants of humanity, decide that humans are no longer useful and make an attempt to eliminate them. From the Heuristically Programmed Algorithmic Computer (HAL) in Arthur C. Clarke’s Odyssey series to the Terminator film series’ malevolent Skynet, our collective imagination seems to harbor the fear that our machines are out to get us. That may be unlikely for the current generation of industrial robots—but that doesn’t mean they’re completely safe. As Little Chubby demonstrated, even a toy robot can inadvertently put human life and limb at risk.
Fate in a Microsecond
Robots are an indispensable tool in modern manufacturing—but so are the humans who work with them. And although they lack the capacity for malice, they can, like Skynet, decide the fate of a human in a microsecond: extermination.
What can be done to make this a safer working relationship? Here are some ways to reduce human exposure to robot hazards, drawn from Section IV, Chapter 4, of the OSHA Technical Manual:
Machine safeguards. A robot is a type of machine, so many of the types of safeguards you would use for any machine also apply to robots. The “restricted envelope” of the robot—the area through which the robot moves, and within which it operates—can be guarded using one or more safeguards, including:
- Mechanical and nonmechanical limiting devices
- Presence-sensing devices
- Fixed barriers
- Interlocked barrier guards
All safeguarding devices should be in place and active when the robot is operating automatically. No part of the operator’s body should be within the robot’s safeguarded area during operation.
Awareness Devices. Devices that make workers aware of the restricted envelope around a robot, such as chain or rope barriers, flashing lights, and signs should be used in conjunction with other types of safeguards.
Maintenance. Maintenance is essential for minimizing the hazards from component malfunction, breakage, and unpredicted movements or actions by the robot or other system equipment. Inspections and maintenance should be performed in accordance with the recommendations of the robot manufacturer and the manufacturer of any associated robot system equipment such as conveyor mechanisms, parts feeders, tooling, gages, or sensors.
Safeguards for teachers. The “teacher”—the person who programs the robot—requires special protective attention. While the robot is being programmed, the teacher has control of the robot and associated equipment and must be familiar with the operations to be programmed, system interfacing, and control functions of the robot and other equipment. The teacher may work within the robot’s restricted envelope, where the activation of improper functions or of an erroneous sequence of functions can cause an accident. During teaching, robots should operate at restricted speeds. Teaching safeguards should also apply whenever a worker enters or approaches the robot’s restricted envelope to evaluate or check the robot’s motion or other operations.
Safeguards for maintenance and repair personnel. The job functions involved in maintenance and repair vary widely. Maintenance workers may troubleshoot faults or problems with the robot, controller, tooling, or other associated equipment; perform program touch-up or scheduled maintenance; and adjust tooling, gages, recalibration, and other functions. System safeguards will be removed or bypassed, and workers may perform their work within the safeguarded area and within the robot’s restricted envelope. At a minimum, the robot should be placed in the manual or teach mode during maintenance and repair.
Tomorrow we’ll take a look at the latest trend in robotics: collaborative robot systems.