Development of Flex-Header Controller for Honey Bee

Brian Fletcher of Honey Bee had contacted Vansco to do a small electronic assembly for them, but Vansco was too large and busy, so they referred him to Elecsys.  We happily took on the task of creating a controller for their new 42 foot combine flex header.

The challenge is that, with a flexible cutterbar out front, you cannot rely on simple bumpers to keep the cuttterbar from interfering with the reel.  It might flex in the middle, coming up and cutting the plastic tines off of the reel.  Those little plastic tines are expensive and very time consuming to replace.

Honey Bee had created six flex points along the length of the cutterbar, where we placed rugged precision pots to measure the displacement of the cutterbar in that region.  We placed another precision pot on the reel arm.  We were able to calculate interference between the reel and cutterbar, and drive the hydraulics to move the reel up and out of the way.

Life isn’t that simple, though.  We needed to have controls in the cab, to configure the system and monitor its operation.  We created an in-cab controller with small display, rotary dial and pushbuttons, which communicated to the controller on the implement using CAN.  At each end, the processor used was a Microchip PIC18F series MCU.

Over the winter, we performed extensive static testing on a flex header using a portable hydraulic pump, at PAMI in Portage la Prairie.  In the spring, we travelled to Honey Bee in Frontier SK to visit the plant and perform more tests.  Over the summer, Honey Bee did extensive testing all over, and I attended testing in southern Manitoba, North Dakota, Minnesota, and Illinois, riding on the combine, watching the system operation, and tweaking the control programming.

An unexpected challenge arose, that of the hydraulic capacity of different combines.  It turns out that some manufacturers have a huge hydraulic operative capacity, and others quite weak.  It’s difficult to accommodate different manufacturers, even with different programming.

Another issue was the retrofit of the controls to the combine.  The hydraulic controls weren’t meant to be tinkered with.  On some systems, we could just drive the solenoids directly.  On others, we had to diode isolate our controls from the existing controls.  On others, the diode isolation set off alarms indicating open circuit on the solenoids.

It was going to be a long haul to make the system compatible with all the potential combine systems.  In the end, Honey Bee could not invest the capital to make a flexible enough system, and Elecsys could not make this investment either.  A further challenge was that the market for the aftermarket flex header that Honey Bee was making, would not bear the several-hundred-dollar premium for such a controller.

Sadly, the controller project ended with only a handful of (very nice looking) prototypes made.