By Marcel Kars, VP, Warehouse Automation, Zebra Technologies: Over the last decade, many customers have asked me for a cheat sheet of dos and don’ts when selecting and deploying a mobile robot solution, and the one thing I can say with certainty is to prioritise worker safety.
According to Eurostat, the statistical office of the European Union, there were 3.1 million non-fatal accidents that resulted in at least four calendar days of absence from work in 2019, the most recent year for which there’s complete published data. The same report listed manufacturing, wholesale and retail trade, and transport and storage among the industries with higher rates of non-fatal injury.
Mobile robots, by definition, are mobile. Though not all are free roaming (autonomous), many are. In fact, autonomous mobile robots (AMR), which can move dynamically throughout a facility, are expected to make up more than half of the deployed mobile robot fleet worldwide by 2025.
As mobile robots have increasingly become a staple of automation in manufacturing, warehousing and distribution environments, more and more customers are trying to figure out the best way to successfully deploy mobile robots in their facilities.
Therefore, it’s important to properly train and engage with workers about their new robot co-workers to help ensure everyone stays safe while working closely together.
As my colleague Melonee Wise, Vice President, Robotics Automation at Zebra Technologies says, that may seem like an easy action item for automated guided vehicles (AGV), as they are limited to transit lanes marked by magnetic tape, wires, or beacons. Although it may be easy to train workers about the fixed paths of the AGVs, it may not be practical or possible for workers to stay out of an AGV’s path.
And unlike AMRs, AGVs aren’t capable of obstacle avoidance. This will cause the AGV to 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 this specific mobile robot solution.
Because of this limitation, many customers are increasingly looking to use AMRs over AGVs for the increased freedom provided by obstacle avoidance. Obstacle avoidance technology is the key to making AMRs smart and agile enough to manoeuvre around people, lift trucks, pallets and more. So, instead of teaching people to avoid robots’ paths and hoping they stay aware of their surroundings, we use AMRs that can accommodate the dynamic facility environment and the people in it.
However, not all AMR collision avoidance technology is made equal and sometimes certain situations or human behaviours 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 wasn’t paying attention or was looking at their phone while crossing a robot path. But the employer is responsible for reducing risk to employees by selecting a solution that can function safely in their facility.
Not too Close, Not too Far – Three Considerations
If you decide that AMRs are the best robotics automation solution for your factory, warehouse, or distribution centre – or perhaps your hospital or school, if using as a sanitation solution – it’s 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.
If you’re 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: 1. 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 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 can’t go, not all hazards can be avoided. But they must be considered when weighing your automation options.
2. Choose mobile robots that are capable of avoiding common obstacles in your facility, including people, forklifts, machinery, and shelves, even when reversing. Don’t put 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.
3. 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 sanitise 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.
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 co-workers. 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.
Working Regionally, Thinking Globally Around Mobile Robot Safety
Published in December 2020, the ANSI/RIA R15.08 safety 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 important for warehouse companies to understand the requirements outlined in ANSI/RIA R15.08 for deploying and operating an AMR solution in their facilities.
Warehouse companies will most likely be following a regional standard such as the machinery directive in Europe covered by the CE mark. However, ANSI/RIA R15.08 will most likely be harmonized globally with other regional standards, and companies can get ahead from a safety perspective by conforming to ANSI/RIA R15.08.
In other words, take care to prepare your facility and your workforce for robots using R15.08 as your guide. And maximise 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.
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