ACS Motion Control has developed several advanced motion control algorithms for its SPiiPlusNT family of motion controllers and drives, designed specifically for linear motor based closed track transportation systems. Such systems offer improved performance at a fraction of the cost when compared with traditional moving magnet based closed track transport systems. Now, manufacturers and users of linear motor based closed track transportation systems have an off the shelf control solution, and users of moving magnet based systems, limited by motion performance, have an alternative solution.
ACS’ unique algorithms adaptively compensate for the changes in commutation period and motor force constant that result from curved shape magnets in the curved linear motor track. The algorithms also provide seamless transitions between feedback devices during motion, which allows high resolution optical encoders to be used along certain regions of the track. Additional advanced control algorithms, such as ServoBoost, may be used to further improve performance. A powerful multi-tasking application layer enables robust anti-collision, where anti-collision zones can be modified on the fly to meet application needs.
Featuring a simple control scheme that treats each motor forcer on the track like a standard linear motor axis, ACS’ solution for closed track transportation systems provides higher performance via:
- Sinusoidal commutation for considerably smoother motion
- High resolution optical encoders may be used at the required regions (i.e. printing zone)
- Lower cogging that can be completely compensated by algorithms
- Position error of a few microns or less during motion
“Moving magnet motion solutions are primarily used in closed track transport systems, and typically require complex commutation control, multiplexing between sensors and several (non-standard) drives, one for each section of track - meaning the number of drives required increases with the length of track,” said Boaz Kramer, Director of Control & Support at ACS Motion Control. “Moving magnet solutions also have limited performance, as they usually implement a 6-step trapezoidal commutation and hall-sensor based feedback, which have limited resolution and accuracy. Plus, with limited force constants, moving magnet solutions are not suitable for many applications like high performance printing machines.”
ACS’s motion control solutions for closed track transportation systems only require one drive for each moving forcer and are not dependent on the track length. The ACS motion control solution is significantly more cost-effective, and provides lower cogging, better performance, and higher motor force constants (up to 1900N continuous).
The motion control algorithms are already being used in high-throughput digital printing, 3D printing, medical and packaging applications.
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