Human-Robot Interaction in the Factory of Tomorrow

Human-Robot Interaction in the Factory of Tomorrow.

Human-Robot Interaction in the Factory of Tomorrow

Robots are a regular fixture of manufacturing, but they’re typically run in isolation to prevent potential risks to workers, and this takes up a tremendous amount of space on an average shop floor. New safety techniques and advanced automation technology are now clearing the way for normalized human-robot interaction that would eliminate many cumbersome space and operational requirements.

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Robots play an increasingly large role in manufacturing as companies seek to raise efficiency, reduce errors, and improve speed in the supply chain. But while robots can accomplish much on the factory floor, there are still drawbacks to their use. Most robotic processes still require regular human intervention and assistance. Because robotic tasks generally operate at high speed and with great force, robots can present dangers to humans working nearby.

Robots need a great deal of space, known as “exclusion zones,” for safety: areas human personnel must keep clear of to avoid accidents with machinery, according to standards enforced by the Occupational Safety and Health Administration (OSHA) and the Robotics Industry Association (RIA). When a human needs to enter these exclusion zones – which are usually cordoned off by barriers – companies must follow a complex work stoppage procedure to ensure safety.

This requires a significant commitment of valuable floor space. Once robotic equipment is installed and enough space is cleared for safety standards, the robotic process becomes “fixed” and sizable expenses and facility changes are needed before the robot can be repurposed for other tasks.

For this reason, ironically, the presence of robots can pose a barrier to efficient production.

According to many in the robotics industry, the solution is to rethink how humans and robots interact. This way, companies that use robots can create reconfigurable manufacturing environments that allow them to use less space and quickly repurpose robotic equipment for different tasks.

Today, many organizations, both private and public, are on a quest to build a better, safer robot that can easily work with humans. These organizations are building prototypes of cutting-edge robotic equipment that incorporate sensors to allow them to slow down or stop when they sense the proximity of human workers.

Some companies have experimented with 360-degree laser fields that allow a robot to “feel” the approach of humans or objects and stop or slow its processes accordingly. Other designs have proposed having human workers wear radio-frequency identification (RFID) tags the robot can “read” when they are in close proximity.

The potential here is great. These technological innovations could allow robots to literally work alongside human workers, rather than in exclusion zones, sharing tasks with employees and saving time through production efficiencies.

Human-friendly robots are largely still in the drafting, testing, and prototype phases. The National Institute of Standards and Technology (NIST) Engineering Laboratory is currently engaged in a study that aims to develop a measurement science for characterizing and modeling interactions between humans and robots in what is known as “flexible factory environments,” which means the use of robots in a way that can be regularly adjusted, changed, and reconfigured.

Elena Messina, leader of the Manipulation and Mobility Group at NIST’s Next Generation Robotics and Automation Systems Program, believes this will reduce the burden on manufacturers that use robots, and may allow more companies to adopt robots – especially small and medium enterprises that may not be able to afford the floor space and constraining nature of legacy robot safety standards. The breakthroughs, she noted, will need to be multi-disciplinary.

“Both hardware and software advancements are needed to enable more collaborative robotics,” Messina told IMT. “On the safety front, there are two main approaches to promoting greater human-robot interaction. One is speed and separation monitoring (SSM). The second is power and force limiting (PFL). Both approaches rely on sensors that provide input to algorithms and affect the robot’s control software.”

With SSM, external sensors are used to detect humans within the robot’s workspace, allowing the robot’s control software to respond accordingly to avoid contact. If a human is detected within an outer zone near the robot, the robot slows down. If a human enters a smaller zone that puts it within reach of the robot, the robot stops entirely. Once the human is perceived to have vacated the “stop” zone, the robot resumes its path at the slower rate until the human exits the “slow-down” zone, at which point it resumes normal speed.

PFL applies when there is contact between a human and a robot, causing the robot to maintain power and forces within safe levels that will not injure the human worker. The robot uses sensory data determined by force and torque sensors to adjust its own power and force levels. One of the NIST lab’s tasks is to help the standards community define what constitutes safe levels.

Ultimately, Messina explained, manufacturers will be able to use robots as true co-workers, assisting and augmenting human work on the factory floor. Reducing the infrastructural requirements for safety will enable robots to be installed in more facilities and at lower costs, and enable robotic systems to be more mobile and multipurpose.