Engineers at Modra Technology, Warragul, Australia, developed a servodriven machine that could quickly make samples for various carpetmakers’ lines of tufted carpets. The Mtuft machine had to be flexible enough to replicate carpets made on a wide range of automated looms.

Mtuft holds the web (backing material for a carpet sample) in tension on two back drums. Two reciprocating heads, one above and one underneath the web, travel the width of the sample. Needle motors provide the reference signal for all interpolated axes. A larger servo moves the needle through a drivenspine arrangement that keeps down the weight of the head.

“We effectively have a software calibrator that lets us put a variable offset into the system,” explains Tim Modra, managing director at Modra Technology. “Instead of using precise gears and cams, which are expensive, time-consuming to configure, and inherently inflexible, we now calibrate the machine digitally.”

Mtuft can make 3.3 or 6.6-ft.- wide samples of cut/loop and cut/ multipile carpet of any length in single or multiple colors. It makes up to 30 stitches/sec, letting it create a typical carpet sample in 20 min.

The all-servo Mtuft handles motor communication over a highspeed Ethernet Powerlink network from Baldor Electric Co., Fort Smith, Ark. The Ethernet-based motion controllers and servos avoid the real-time data transmission limits of Ethernet but still use standard Ethernet cabling. Powerlink manages message exchanges in a precise sequence that lets only one node communicate at any one time. This adds determinism to Ethernet communications. Powerlink protocols ensure all time-critical data transfers within configurable isochronous bus cycles to prevent data collisions associated with standard Ethernet. The protocols eliminate the need for bus arbitration schemes, thus reducing transmission time overheads.

A Baldor NextMove e100 controls all nine electrically operated axes. Baldor MicroFlex e100 single-phase ac servodrives and BSM servomotors drive seven axes, with Ethernet Powerlink handling communications between controller and drives. Five of these axes rely on interpolation, which is also handled over Powerlink. Two other electrically driven axes use small dc motors.