Seventh-Axis Linear Rail for Cobots offers Collision Detection

Thomson Industries Inc. has developed what it says is the first true collaborative extension of cobots with its Movotrak cobot transfer unit (CTU) seventh-axis linear rail. Adding a maximum horizontal operating range of 10 meters, the device is distinctive in that its collision detection feature stops the cobot as it traverses down the rail when it encounters an obstacle, facilitating human collaboration while increasing productivity.

“With the extension of the collaborative functionality along the seventh axis, manufacturers can deploy cobots to work more closely and flexibly with humans,” says Kyle Thompson, product innovation manager at Thomson. “Using the same cobot for more than one workstation boosts productivity and extracts maximum value from the initial cobot investment.”

Also known as a range extender, the Movotrak CTU features a Kollmorgen servo motor and linear-unit-driven guide rails that move a cobot assembly from one task location to another. However, unlike other seventh-axis units, the Movotrak CTU has collision detection functionality similar to a cobot joint. Users adjust collision sensitivity settings on a control tablet during setup, and the Movotrak CTU motor drive and digital I/O manage the collision monitoring and shutdown.

The collision detection system also monitors current continuously, detecting position errors in the motor and providing comprehensive anti-collision capabilities along the entire seventh axis. The system includes a small reverse-move feature that eliminates pinch points following a stop.

The Movotrak CTU integrates with many cobot sizes and brands including ABB, Denso, Doosan, FANUC, Kassow, Kawasaki, Techman, Yamaha and Universal Robots (UR), the last of which enables all programming to be done directly through a URCap interface on its UR Teach Pendant. All collision monitoring and safeguard logic runs in the Thomson drive, so bandwidth competition with the UR controls is said to be minimal.

Similar to the freedrive of cobot joints, the Movotrak CTU freedrive functionality enables hand-driven setting of linear waypoints during programming. Users manually slide the cobot where they would like it to be in a sequence along the seventh axis and register that with a simple button push. A good use case example of this feature is an aircraft quality inspector who needs repeated images of the same area over time. Another might be a welder who wants to carry out welding sequences at multiple locations. For shops, the device with 10-meter range could enable a cobot to tend multiple machines installed side by side.

The Movotrak CTU distinguishes itself through its innovative dual-linear unit solution, delivering high moment load capacity and stiffness. This design is said to ensure performance and reliability even when fully extending the cobot arm. The unit can be mounted in a horizontal, inverted or wall-mounted configuration, making it an adaptable choice for diverse applications. Notably, the Movotrak CTU is well-equipped for compatibility with even the largest cobots, such as the UR20 and UR30, responding to the high demand for such configurations.

For shops, the device with 10-meter range could enable a cobot to tend multiple machines installed side by side.

Collision detection settings provide users with enhanced capabilities, including:

• User-adjustable collision detection on the Movotrak CTU which performs similar to robotic joints.
• Sensitivity setting during installation per application requirements.
• Large surface areas on the linear carriage which act as paddles enabling for a safeguard stop when contacted.
• All collision monitoring conducted on the Movotrak motor drive and/or digital I/O with minimal processing required from the UR controller.
• Safety I/O connections for all stopping scenarios which are supplied by the cobot and third-party safeguard devices.

Available immediately, the Movotrak CTU ships as a kit, including the linear units, gearhead, motor, drives, control box, software, end-of-stroke limit switches and cable management.

In addition, Thomson now offers a new industrial robot transfer unit (RTU), which can be easily integrated with a user’s preferred motor and drive. This enables users to add seventh-axis movement for their industrial robots. With the Thomson RediMount motor mounting adapter kit included, users can integrate their motor in less than one minute and use their own robotic controller to take advantage of the RTU, the company says. Compatible with many robot brands and sizes, the industrial RTU features the same dual-linear-unit design and carriage-mounted mounting plate as the Movotrak CTU.