Given the release of a new collaborative robot from Yaskawa Motoman, it seems appropriate to ask the question: what do cobots offer that traditional robots don’t?
Why use a Cobot?
What are the use-case differences between cobots and traditional robots?
In the ideal case, traditional robots are integrated and programmed into a finely-tuned, cycle-time optimized cell, isolating the robot’s entire range of motion from human contact during runtime.
Collaborative robots, on the other hand, are optimized for safety, flexibility and collaboration. Cobots are well-suited to high-mix, low volume operations because of their relative ease of deployment. Because cobots don’t require guarding, they can operate a variety of machines or workstations alongside humans. Of course, these extra features and constraints usually make them slower and more expensive than their non-collaborative counterparts. So, what’s the point?
For a simple example, consider a typical production floor with several five-axis CNC milling machines. Typically, each of these machines is operated by a machinist, with a cobot performing another task, such as ultrasonic cleaning on trays of finished parts. When an order comes in for 1,000 machined brackets, the cobot can be wheeled over to a CNC machine, set up with stock material and programmed to tend the machine. The machinist is then free to perform other tasks. When the job is done, the cobot can be returned to the ultrasonic cleaning task and the machinist can begin setting up for the next job on the machine.
Why is a cobot so much better for the above case than a traditional robot? Simply put, it’s the collaborative capability of the robot that allows it to rapidly switch between tasks and work alongside the other operators. It’s also why the machinist was able to return to his machine afterward with virtually no set-up. With a traditional robot, both workstations would need guarding installed, resulting in lost time—either in the form of setting up and taking down temporary fencing, or in the form of having to work around permanent fencing when the robot is not in the cell.
Collaborative Robots – Key Features
The safety guidelines for industrial robots are outlined in ISO 10218. Last updated in 2011, the document specifies the safety guidelines for all industrial robot deployments, such as guarding requirements. However, ISO 10218 does not account for collaborative robots and their built-in safety features. To address this, ISO published a new technical specification, ISO/TS 15066:2016.
According to Universal Robots CTO Esben Ostergaard, the technical specification has helped significantly in growing the cobot market, as the guidelines help customers purchase and integrate cobots more confidently.
What are the key design features that distinguish collaborative robots from traditional robots? The newest cobot from Yaskawa Motoman, the HC10, is an excellent example.
Featuring power and force limiting technology, the HC10 collaborative robot works safely with or near humans by stopping the robot in the event of contact with an operator. Dual torque sensors in all joints constantly monitor force to react to contact. A feature you may notice is common to all cobots is the smooth, rounded plastic arm. This is designed to eliminate operator pinch points, while through-arm utilities hide cabling and increase safety by reducing the risks of snagging or interference with other equipment.
In addition to traditional robot programming through the teach pendant, the user can hand-guide the HC10 robot when teaching new program paths. This teaching method is part of what allows cobots like the HC10 to be redeployed on demand, decreasing system downtime.
The HC10 offers a 10-kg payload and 1,200 mm reach and can perform a broad range of material handling, machine tending, packaging or light assembly tasks. Function-specific tooling and accessories are available from various Yaskawa partners.
The HC10 robot is controlled by Yaskawa’s new YRC1000 controller that does not require a transformer for input voltages ranging from 380VAC to 480VAC. According to Yaskawa, its I/O communication speed has been improved by as much as 50 percent. The programming pendant was redesigned to enhance ergonomics and reduce weight.
For more on how collaborative features can be effectively leveraged in your industrial automation application, read 4 Innovative Uses of Force/Torque Sensing That Broaden Cobot Applications.