A Uniform Interface for Robots

Nov. 5, 2021

Once again, a group of companies has banded together to create a vendor-independent standard and found a home in Profibus International to promote, harmonize, and certify their technology.

Michael Bowne

Related To: PI North America

In today’s manufacturing plants, the presence of robots is increasing every day. They are often arranged, along with other machines, in cells, each for a different step in the manufacturing process. A robot cell will typically consist of a robot controller (RC), the robot arm itself, a dedicated human machine interface (HMI) pendant, and the engineering software employed to program the robot. A single vendor typically supplies all four components. Meanwhile the entire manufacturing line is orchestrated separately by one or more programmable logic controllers (PLCs). The PLC interacts with the RC to synchronize the whole process.

A problem with this setup is that an end-user will often have multiple robots from different vendors that need to interact with the PLC. This is quite challenging because each vendor has its own way of programming. The programming is implemented via a library provided by the vendor. Each library is proprietary and different for each robot vendor. Generally, this inhibits independence by promoting vendor lock-in and greatly increases the complexity of programming robots.

Robot control with proprietary robot interfaces and libraries.

A solution based on standardization
The goal of the new “Uniform Robot Interface” is to have a single interface between the PLC and the RC. This would eliminate the unique libraries from each robot maker and standardize the programming across brands. There are additional benefits beyond standardizing the motion commands between PLC and RC, such as the ability for an end-user to operate the robot arm via an HMI connected to the PLC in the same way as the dedicated HMI provided by the robot vendor. The interface could also allow for the gathering of diagnostic information from the RC and robot arm in a standardized manner.

Vendor and protocol independence
While currently being implemented via Profinet, the standard can run over any communication protocol. The interface can be implemented just as well over OPC UA or any other industrial Ethernet protocol. The effort is driven by a collection of the world’s largest robot makers: Stäubli, ABB, Fanuc, Comau, KUKA, Yaskawa, Kawasaki, Yamaha, Panasonic, Techman, and Epson.

PLC vendors are welcome to participate in this effort as well. As of Q3 2021, the specification is fully written and currently under review at Profibus International (PI) in preparation for public release. The Uniform Robot Interface is being incorporated and fits well into the broader PI technology portfolio of Profibus, Profinet, IO-Link, and omlox. It is another step in the organization’s evolution from one focused purely on data communication to one helping speed up digitalization across the industrial space.