Guidance system takes on tall corn

FARGO, N.D. — The latest generation of GPS steering devices eliminates the need for all other guidance systems, right?

Maybe not.

Dribbling between-row nitrogen or running a combine in tall corn can present issues that GPS has difficulty handling, according to Carol Paquin of Reichhardt Electronic Innovations in Sabin, Minnesota.

“As good as GPS guidance may be, the planter doesn’t always follow the tractor perfectly. Planter drift can be significant on side slopes,” said Paquin, who was at the Big Iron farm show in Fargo to promote the Reichhardt Tactile Row Guidance system.

“When you’re spraying or dribbling nitrogen between the rows, or even combining, you need a way to follow the corn rows where they actually are, not where the GPS says they should be.

“That’s why Reichhardt developed an automatic steering system they call Tacticle Row Guidance. It mechanically senses where the rows really are, then converts that information into digital signals for your steering system.


It either connects directly to the electronics in your steering or plumbs into the hydraulics.”

The concept is similar to the Seed Hawk Seed Between the Rows system, but the Reichhardt system shines in tall corn.

Paquin said that when installed on an applicator, two tactile row sensors attach to the front of the crop dividers or they hang from the centre of the machine.

On a combine, one sensor attaches to the nose of a row divider. Each tactile row sensor consists of a long yellow paddle fastened in the centre, so it has two wands extending out to the sides.

Magnets at the base of the paddles line up with magnets in the bracket at the fixed centre point. The magnets are wired to a hall-effect sensor, which is a thin strip of metal with an electrical current. As the distance between the magnets change, the electrical current changes and sends the appropriate signal to the controller.

When the wands are extended straight out in the neutral position, the magnetic field within each pair of magnets is electronically static. The status quo reading tells the steering system that everything is fine. No action is required.

As the machine drifts left or right, the wand on that side pushes against corn stalks, causing it to flex backward. As it bends at the fixed centre point, the gap between the magnets increases and the strength of the magnetic field changes.

This change is electronically measured. As the machine drifts closer to the corn row, the wand bends back even further and the variance in the magnetic field increases.

The system instantly tells the steering system that the neutral status quo has been violated, and to what degree. A minor flex of the wand creates a minor steering adjustment.

A more severe wand warp creates a bigger gap between the magnets, thus triggering a more significant steering correction.

“If you hit a planter skip, the software is smart enough to recognize it and keep the machine on course. It won’t over- react. It just reads off the correct row.”

Corn on a side slope is one of the most common situations the Reichhardt system rectifies. The tractor mounted GPS may have allowed farmers to do a good job of planting in a straight line, and their system has memorized those row patterns, but the corn plants have not grown out at a 90-degree right angle to the surface. The corn plants instead have grown straight up, so now, the tops of those stalks are offset from the root row.

“We’ve been selling the system for combines for about 10 years, then two years ago we made them available for sprayers.

The system is produced by Reichhardt in Germany, but the tactile sensor was developed by a fellow in Arthur, North Dakota.”

The system for sprayers has two sensors and sells for US$8,200. The single sensor system for combines sells for $6,100.

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