When Visteon Electronics first deployed its fleet of four autonomous mobile robots, or AMRs, employees were skeptical — and concerned about mobile robot safety. Would they be able to transport materials throughout their plant without running into people or other robots? It didn’t take long for the employees to see that as the AMRs maneuvered through the manufacturing facility around the clock, they avoided obstacles and could actually recompute their paths on the fly.
In fact, extensive built-in safety mechanisms allow Visteon’s robots to navigate collaboratively around human co-workers and other obstacles by slowing down, changing direction, or stopping completely to avoid collision.
Employees soon appreciated that the robots freed them from heavy, monotonous, and low-value material-moving tasks. And with increasing confidence in the mobile robot safety features, they soon supported the implementation.
Before implementing the robots, however, management had to be onboard as well, as employee safety must be a top priority. Sensors, software algorithms, and artificial intelligence capabilities are key to a safe mobile robot installation, so the AMRs’ safety features were carefully researched before being purchased.
But companies have additional responsibilities to ensure a safe environment by working closely with their AMR manufacturer and integrator to comply with evolving standards that ensure safe conditions for workers who interact with these robots.
Below is an outline of relevant standards and laws that are in place today. New standards amended for AMRs are under development and scheduled to be introduced in 2020.
Applicable mobile robot safety standards
In Europe, the most applicable standard for AMRs today is EN 1525:1997 (“Safety of industrial trucks – Driverless trucks and their systems”). This standard applies to an automated guided vehicle (AGV) as well as its systems. It also applies to the commissioning and preparation of the environment in which the robot will be used.
A possible successor to EN 1525 as the most applicable standard for AMRs is ISO/FDIS 3691-4: “Driverless industrial trucks and their systems,” which is scheduled for release in January 2020. ISO/FDIS 3691-4 addresses safety concerns for internal logistics and the hazards related to recompute paths on-the-fly, which are key aspects of AMRs. The new standard will provide detailed requirements for commissioning mobile robots as well as environment and work-cell design.
In the U.S., the American National Standards Institute/ Industrial Truck Standards Development Foundation wrote the 5-2012 standard to address AGVs. It has the same scope as EN 1525.
Other standards in progress that will likely have impacts on manufacturers, users, and integrators of mobile robots in the future include ISO 10218, prRIA 15:08, and prUL 3100, each of which addresses different aspects of AMRs and their implementation.
European guidelines set the stage for global safety
In addition to standards, the European MD (machinery division) has created guidelines to help vendors, end users, and integrators create a safe workspace. Manufacturers outside the European Union are not required to follow these guidelines, but the European standards provide a solid framework that can be applied to all factories with amendments to address local requirements.
First, the manufacturer of the AMR must provide a vehicle that is designed to be commissioned in a safe AMR system, which includes the environment, charging station, top modules, and other peripherals.
It must also provide adequate information for integration and operation. This means that the manufacturer is responsible for specifying intended use and limitations of the AMR, which is typically to transport materials without a driver in industrial environments.
The manufacturer must CE-mark the AMR according to intended use through compliance to safety standards for AGVs (what most of today’s standards are based on). They must also comply with complementary standards to address all risks, and provide integrated safety functions to address hazards expected in the intended use.
In addition to designing a safe robot, the manufacturer must also provide adequate documentation, including instructions regarding commissioning of the AMR into a mobile robot system, operating instructions for operation and maintenance of the AMR, and a list of identified residual risks for the AMR. Ultimately, the manufacturer is responsible for providing a safe AMR out of the box with all the required documentation.
Responsibility moves to integrators, end users
When the robot is ready to be installed, the responsibility for a safe workplace moves to the integrators of the AMR system, which may be an end user if it is integrating the robot itself. The integrator must provide an installation where all hazards are addressed or identified while providing adequate information for operation.
Because AMRs can be programmed to move throughout a building, factory, or warehouse, the integrator who commissions the AMR must anticipate potential safety hazards and program the robot to act appropriately in compliance with safety standards. Commissioning also extends to the top module.
If the robot is commissioned outside of those limitations, the integrator (or end user) must incorporate additional protections to ensure that safety standards are met for the full robot application. The integrator must therefore specify the intended use and limits of the AMR system and make a risk assessment of the AMR system in light of the AMR manufacturer’s specifications, intended use, and limitations.
As the application changes from an AMR to an AMR system, the integrator must CE-mark the AMR system according to the new intended use, and provide documentation consisting of operating instructions for operation and maintenance of the AMR system and a list of identified residual risks from risk assessment for the AMR system.
Once the AMR system has been deployed, the end user is then responsible for setting up and following procedures for operation and maintenance. The end user must ensure that the intended use and limitations are met, and set up procedures for inspections and maintenance for the AMR system, including warning and markings. The end user should define safe operating procedures for operators and define training for operators, other staffers, and visitors for safe operation.
The complicated process to ensuring a safe workforce around autonomous mobile robots can be facilitated by following the chart below, or by contacting the AMR vendor being considered to help effectively — and safely — navigate the process.
With the increasing number of AMRs being installed, new AMRs on the market, and new customers with limited experience with this technology, every relevant member of the implementation team must work together to ensure a safe workplace. It’s too important to try to do alone.
About the author:
Ed Mullen is vice president of sales, Americas, at Mobile Industrial Robots ApS.