The Fallacy of Fencelessness, Why Cage Free is Best Part 1 — Veo Robotics
By Alberto Moel (Vice President Strategy and Partnerships) and Clara Vu (CTO / co-founder), Veo Robotics
In recent months, flexibility in manufacturing has been top of mind. To keep pace with market needs, manufacturing must become more flexible to continuously adapt to change, especially during a crisis like the current one. Although the press and industry have picked up the topic recently, the need for flexibility in factories has been an ongoing concern and issue for manufacturing engineers for quite some time.
A powerful way to introduce flexibility in factories is by simultaneously taking full advantage of robots, which are the most flexible machines in a factory, and humans, which are the most flexible resource. But humans must be kept separate from robots with fences or other guarding equipment to ensure worker safety. This separation introduces frictions and inefficiencies that limit how manufacturing processes can respond to rapidly changing product and market conditions. Allowing humans and robots to easily and safely work together in the same space will enable a much more flexible manufacturing environment.
To that end, the manufacturing industry has invested heavily in the development of safe collaborative applications for humans and robots. Standards such as ISO 10218-1 and ISO/TS 15066 outline four different methods of safe human-robot collaboration: safety rated monitored stop, hand guiding, Power and Force Limiting (PFL), and Speed and Separation Monitoring (SSM).
Two of the reasons people are interested in applications with safe human-robot collaboration are to remove fences and reduce floor space, but in many cases these two goals are actually at odds with each other. In today’s post we’re going to address this contradiction and show that in many applications limited fencing or guarding is desirable (or even required) to improve workcell economics, ensure workcell safety, and result in more fluid human-robot interaction.
PFL and SSM: The leading candidates for useful human-robot collaboration
The most widely available and commonly understood (and misunderstood) form of collaborative robotics in manufacturing applications are PFL robots, often known as “collaborative robots” or “cobots.”
A PFL robot controls hazards by limiting the power and force the robot can exert before stopping. PFL has had a major impact on how we think about collaborative manufacturing, but the technique does have limitations. A stop is triggered only when the robot hardware detects a collision, so this approach only works for smaller, slower, lightweight robots that won’t harm a person by coming in contact. But even a small, lightweight robot is considered hazardous when it’s carrying a sharp object, so PFL robots are also limited in end-effector designs and types of payloads.