Safety First - Ensuring Mobile Robots Will Not Pose a Risk to Workers

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Zebra Technologies Logo Mobile robots have become an automation staple in manufacturing, warehousing and distribution environments, with more to come. In many instances, companies are unsure how best to successfully deploy mobile robots in their facilities. Over the last decade, many customers have asked me for a cheat sheet listing the “dos and don’ts” when selecting and deploying a mobile robot solution. The one thing I can say with certainty is to prioritize worker safety.

Safety Critical
Mobile robots, by definition, are mobile. Though not all are free roaming (autonomous navigation), many are. In fact, autonomous mobile robots (AMRs), which can move dynamically throughout a facility, are expectedto make up more than half of the deployed mobile robot fleet worldwide by 2025. Therefore, it is important to properly train and engage with workers about their new robot co-workers to help ensure everyone stays safe while working closely together.

Automated Guide Vehicles (AGVs)
“Ensuring safe operation” may seem like an easy action item for automated guided vehicles (AGVs), as their movement is limited to transit lanes marked by magnetic tape, wires, or beacons. Although it may be relatively simple to train workers to avoid the fixed routes of the AGVs, it may not be practical or possible for workers to stay out of their paths.

AGVs are incapable of obstacle avoidance, unlike AMRs. When workers impede an autonomous guided vehicle, the system must slow down or stop completely and wait for the worker to get out of the way. Unfortunately, this limitation reduces the productivity and effectiveness of AGV solutions.

Autonomous Mobile Robots (AMRs)
Given that AGVs lack navigation autonomy and obstacle avoidance capabilities, many companies are turning to AMRs in place of AGVs. Obstacle avoidance technology is the key to making AMRs smart and agile enough to maneuver around people, lift trucks, pallets and more. So, instead of instructing workers to avoid robots’ paths and hoping they stay aware of their surroundings, companies utilize AMRs that can accommodate dynamic, unstructured environment and the people in it.

AMR collision avoidance technology varies from system to system, and sometimes certain situations or human behaviors can lead to the robot bumping into or colliding with a human. But bumps lead to bruises, and repetitive bumps and bruises lead to pain and distrust in their robot coworkers – even when they are soft contacts. For automation to be valuable, people and robots must work in harmony. Plus, any type of unplanned contact leads to increased liability on behalf of the facility operator, regardless of why the contact occurred. It may be that the worker was not paying attention or was looking at their phone while crossing a robot path. It is critical, therefore, that employers select AMRs solutions that are optimized for safety and can operate safely in their facility.

Fortunately, teaching associates how to work with AMRs is simple, and it may only take a few hours for them to find a rhythm.

Safe Distancing Measures
If you decide that AMRs are the best robotics automation solution for your factory, warehouse, or distribution center – or perhaps your hospital or school, if using as a sanitation solution – it is important that you choose robots that can operate properly in your facility. Confirm they have cameras, sensors and safety features to detect and navigate around overhanging objects, forklifts, people, or other common hazards found within your facility. More specifically, verify the AMR solution conforms with the ANSI/RIA R15.08safety standard published December 2020.

The ANSI/RIA R15.08 standard specifies safety requirements for mobile industrial robots for the manufacturer, integrator, and end-user. As the end-user of the automation solution, it is equally important to ensure that you understand the requirements outlined in ANSI/RIA R15.08 for deploying and operating an AMR solution in your facility.

If you are a facility administrator or operations manager deploying AMRs to work alongside your workforce or support building sanitation, there are three things you should consider from a safety perspective:

Confirm that your facility is appropriate for mobile robots. – There are many hazards that could render AMRs a non-viable solution for certain applications. For example, AMRs can see a lot of things, but depending on your AMR vendor, they may not be able to see certain features in the environment like ramps or loading dock ledges. They also may not be able to work in cold/freezing environments or areas with water on the floor. Though some of these permanent infrastructure designs can be accommodated during set up when mapping the facility to show AMRs where they can and cannot go, not all hazards can be avoided. But they must be considered when weighing your automation options.

Choose mobile robots that are capable of avoiding common obstacles in your facility, including people, forklifts, machinery, and shelves, even when reversing. – Do not place the onus on associates to avoid collisions. People should be able to move freely around your facility without getting bumped by a robot or worrying about playing chicken with a robot. Ask the AMR system provider if the robot has any blind spots when navigating, floor-to-robot height vision, as well as dynamic obstacle avoidance, which enables the robot to plan around moving objects and avoid pulling out in front of oncoming traffic. This is where specs such as laser sensors, 3D cameras, and advanced software become important. Perhaps more important, though, is the answer to this question: “How many human-robot collisions have your robots had in current or past deployments?” That leads me to the next requirement.

Show people how to engage with (and trust) robots. – AMRs are going to be a new experience for most workers, even if they’ve engaged with AGVs or robotic arms in the past. AMRs are the first robots to be smart enough to work independently and in a free-range manner. Yes, they rely on human associates to do their jobs – robots need direction on where to go to pick up or deliver items or how often to make the rounds to sanitize a facility. But their movements aren’t being controlled by people, just their task lists. So, associates need to feel comfortable moving in the same space as these robots.

Education and Trust
Side 2 Fortunately, teaching associates how to work with AMRs is simple, and it may only take a few hours for them to find a rhythm. Trust may take some time to build, though. The more they work together and associates see there is no physical threat from robots, the more they’ll appreciate their new coworkers. Plus, AMRs alleviate a lot of the physical pain that comes with walking for hours or lugging materials around by hand. Be sure to ask the solution provider about how their AMRs prevent people from becoming pinched between the robot and a fixed object like a shelf. This is important because the employee may not always be able to step out of the way of the robot into a clear area with no other object and may find themselves pinched or trapped between a shelf and a robot.

Adopting a Global Mindset Around Mobile Robot Safety
If you are reading this article outside outside of North America, you will most likely be following a regional standard such as the machinery directive in Europe covered by the CE mark. However, the North American ANSI/RIA R15.08 safety standard (For Industrial Mobile Robots – Safety Requirements ANSI/RIA), recently released by the American National Standards Institute (ANSI) and Robotic Industries Association (RIA), will most likely be harmonized globally with other regional standards. Non-North American companies can get ahead of the safety curve by conforming to ANSI/RIA R15.08 now.

In other words, take care to prepare your facility and your workforce for robots using R15.08 as your guide. And maximize the intelligence of AMRs to ensure they can safely support the high-speed tempo of your operations and give your workers the breathing room they need to be more productive as demands increase.

About the Author
Melonee Wise is the Vice President of Robotics Automation at Zebra Technologies. She joined Zebra through the acquisition of Fetch Robotics where she was the CEO. Wise was the second employee at Willow Garage where she led a team of engineers developing next-generation robot hardware and software, including ROS, the PR2, and TurtleBot. She serves as the Chair of the IFR Service Robot Group, as a robotics board member for A3, and on the MHI Roundtable Advisory Committee. Wise has received the MIT Technology Review’s TR35 and has been named to the Silicon Valley Business Journal’s Women of Influence and 40 Under 40, the Robotics Business Review RBR50, and as one of eight CEOs changing the way we work by Business Insider.