10m-long cobot seventh axis is ‘first’ to detect collisions
5 December 2024 
Thomson Industries has released a seventh axis for cobot (collaborative robot) applications which is describes as “the first ever true collaborative extension of cobots”. The MovoTrak CTU (cobot transfer unit) axis adds a horizontal operating range of up to 10m to cobot installations and incorporates collision detection that stops the cobot if it encounters an obstacle, thus making collaborative operation with humans safer and boosting productivity.
Thomson has also launched an industrial robot transfer unit (RTU) that can be integrated with a user’s preferred motor and drive.
“With the extension of the collaborative functionality along the seventh axis, manufacturers can deploy cobots to work more closely and flexibly with humans,” says Hans Dahlen, Thomson’s product manager for linear motion systems. “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 seventh axis includes a Kollmorgen servomotor, as well as linear guide rails that move a cobot from one position and task to another. Unlike other seventh-axis systems, the new device has a collision detection function similar to those found in cobot joints. Users can adjust the collision sensitivity settings on a tablet during set-up, and the system’s drive and digital I/O manage the collision monitoring and shutdown.
The collision detection system also monitors the motor current continuously, detecting position errors and providing anti-collision capabilities along the entire axis. A reverse move function eliminates pinch points after a stop.
The seventh axis can be used with many brands and sizes of cobot, including those from Universal Robots. In this case, all programming is done via the URCap interface on UR’s teaching pendant. All collision monitoring and safeguard logic runs in the Thomson drive, minimising competition for bandwidth with the UR controls.
A freedrive function allows hand-driven setting of waypoints during programming. Users slide the cobot by hand to where they would like it to stop and register the position with the push of a button. One potential application is for aircraft quality inspectors who need repeated images of the same area over time. Another is welders, who need to carry out welding sequences at multiple locations.
The dual linear system is said to deliver good moment load capacity and stiffness, maintaining performance even when the cobot arm is fully extended. The seventh axis can operate horizontally, inverted or mounted on a wall. It is said to be compatible with the largest cobots – such as the UR20 and UR30.
Thomson’s new industrial RTU allows users to equip their existing robotic applications with a seventh axis. A Thomson RediMount motor mounting adapter kit allows them to integrate their chosen motors in less than a minute and to use their own robotic controllers. The system is compatible with many robot brands and sizes, and uses the same dual-linear design and carriage-mounted mounting plate as the Movotrak CTU.
The seventh axis CTU ships as a kit that includes the gearhead, motor, drives, control box, software, end-of-stroke limit switches and cable management. The RTU version includes dual linear systems, gearhead, motor mounting adapter kit, mounting plate, end-of-stroke limit switches and cable management.
