Control Engineering

Paul Grayson

Precision Farming
April 21, 2008

AUTOMATE OR GO OUT OF BUSINESS
While this advice overheard at a trade show might seem a bit harsh, it is an economic fact of business life. Either you are constantly improving or you are falling behind. With fuel prices hitting all time highs and not expected to come down, the economic balance of everything is shifting and farmers have more economic incentive than ever to automate as many of the farm processes as possible. There are several systems on the market and they are remarkably similar. Most agricultural machinery uses hydraulic steering because there is already a hydraulic system on board to control the implements and it is a simple steering solution to use a hydraulic ram to position the tractors steering linkage. I think the FieldPilot logo is great, two hands in the air has become the international signal to those within sight that the tractor is in full auto.

Ag EQUIPMENT - OTR TRUCKS
Nearly all Ag (agricultural) equipment steering automation kits contain a steering control valve that taps into the hydraulic steering system and is easy for the computer to operate. Over the road trucks on the other hand do not have hydraulic systems and there is a move to reduce parasitic loads on the engine and instead use electric auxiliaries. The efficiency gained here is that they only need to run when they are needed. Things that traditionally were driven directly by the engine such as the lubricating oil pump and the fuel pump are now are electric motor driven as separate auxiliaries. In automobiles the move is toward electric steering systems and it is likely that the truck manufacturers will switch to electric power steering for trucks for the same reasons that automobile makers are shifting. Electric power steering is lighter, more reliable, cheaper to build, and does not require operating fluid.   



MILES OF CROP ROWS
The satellite signal based GPS of the FieldPilot system tells the tractor where it is within about 10" or one tire width. Since the GPS antennas are mounted as high as possible to give them a clear view of as much of the sky as possible, they are a significant distance from the ground and correction for ground slope / tilt of the machine is made to what the vehicles centerline is on the ground. The software that is part of the system is useful for helping to map the fields and plan the path to be taken for each of the operations that need to be conducted in the field to get to the harvest. Typically there are 5 trips through the fields before the harvest. What they are vary with the type of crop and usually represent several passes to prepare the ground, planting, caring for the growing plants, and then harvesting them. Every inch of the filed needs to be covered in each operation so a lot of Ag equipment miles are racked up going between the fences of a field, plus transit to and from the field.

SETUP
The operators screen graphics display shows what the settings are and how to adjust them:
Steering Mode adjustment is for setting the system for manual or automated steering.
Look Ahead adjustment is for adjusting responses to ground speed changes.
Aggressiveness adjustment determines how aggressively the system tracks the line.
Dead Band adjustment specifies the minimum error to correct.
Steering Valve Test allows manual control of the steering valve for testing.

WHAT MACHINERY
Kits are available for 35 tractors and sprayers with more being added every day. Chances are if you are interested in a system, an adapter kit is either available or could be made up quickly to fit your Ag equipment.  


GO ROBOTS !

Paul F. Grayson - Chief Engineer
AMERICAN INDUSTRIAL MAGIC, LLC
Racing to build technology that saves soldier's lives.
390 4-Mile Rd. S.
Traverse City, MI 49686-8411
(231) 946-0187, (231) 883-4463 Cell
pgrayson@aimagic.org  
AIM: http://aimagic.org  
Robot Club: http://tech.groups.yahoo.com/group/robotcluboftraversecitymi/  
CE Magazine: http://www.controleng.com/blog/1180000318.html 


  

Posted by Paul Grayson on April 21, 2008 | Comments (1)