Small industrial articulated robots still present difficulties for design engineers regarding power delivery. Very few appropriate options exist on the market capable of enduring the rapid rotational motions around the first axis and the restricted space available. igus is now addressing this gap with a new self-supporting energy chain from the twisterchain line. This product additionally resolves another issue: the power supply along the fifth axis of palletising robots. In this area, furthermore, numerous design engineers have been testing their own custom solutions.
Compact industrial robots such as the KR AGILUS from KUKA or the FANUC LR Mate can be found everywhere in industrial facilities. They screw, glue, assemble and perform pick-and-place tasks. Although these robots are well-established, one problem has always existed. “The small robots rotate through 360° and require a cable guidance at the base that follows this movement. There are no suitable rotary modules on the market,” says Matthias Meyer, Head of the triflex e-chains and Robotics Business Unit at igus.
The reason for this is often the connector plate for the power supply on the back of the robot, which is in the way of the rotary modules. “Many design engineers therefore still resort to makeshift solutions, such as hanging hoses that drag across the floor and wear out quickly.” To solve this problem, igus is now launching an unsupported twisterchain energy supply. The rotary module is positioned in a sag around the robot base – on the floor or on a raised plinth. The fixed point is attached to the ground, the moving end side is fixed slightly higher on the first axis. When the robot rotates, the energy chain lifts upwards step by step and moves to a new level. “For the first time, it is now possible to rotate through 360° around the base of the robot without colliding with the connector contour,” says Meyer. Improvised solutions are no longer necessary, which significantly increases the reliability of compact industrial robots.
Safe guidance on fifth axis of palletising robots
With the new unsupported twisterchain, igus is also addressing a second problem: the energy supply on the fifth axis of palletising robots. In many cases, these robots guide the cables through the robot arm. However, this often only works up to the fourth axis. “Suitable solutions for the rotary movement on the fifth axis have also been lacking to date. Design engineers often make do with corrugated hoses, which can move around uncontrollably and collide with the tool,” says Meyer. In these cases, the unsupported twisterchain can also be used for greater safety. The specifically developed design makes it possible for the power and data cables on the fifth axis to follow the 360° rotations of the tool. The controlled and defined movement on two levels prevents the cables from colliding with the robot arm or tool. “The system therefore offers maximum freedom of movement for applications with extended rotation angles and ensures permanently reliable energy supply even with highly dynamic movement profiles,” says Meyer.
Quick assembly and easy retrofitting
The new twisterchain variant can be installed quickly. “As the solution is unsupported, we only need two connection points on the robot. Expensive guide troughs and complicated alignments are superfluous,” emphasises Meyer. The e-chains can also be adapted to different cable allocations thanks to a flexible interior separation with removable shelves. Another advantage: the energy chains can be opened in the inner radius so that users can insert the cables from the outside. Says Meyer: “This is a major advantage over hoses that require users to thread the cables. Different connector sizes are always a limiting factor.” The system has an adjustable pretension so that it can be precisely adapted to any application. This can be precisely adjusted to the cable weight and required rotation angle – a decisive advantage for the fine-tuning of robots and machines that require maximum repeatability and stability.