Driving aids help keep you in line
Driving aids help keep you in line
With the help of electronic
driving aids, many tractor
operations could become
vastly more accurate,
leading to greater output
and, ultimately, reduced
costs. It could also avoid
those embarrassing
roadside scenes of missed
drilling and crooked
ploughing. Geoff Ashcroft
looks at some of the
equipment now available
POLES, marker flags and even trees in the distant hedgerow are all forms of driving aid used to get that initial straight run across the field.
But its not just the first run that is so crucial. With wider cultivation equipment, for example, excessive overlaps and missed strips when running across a field all add up to lost productivity and wasted fuel. And it is not just the cultivation process that can suffer – mowing, applying fertiliser without tramlines, and even combining could all be made more efficient with a little guidance.
Enter the latest electronic driving aids – almost a by-product of the GPS revolution – which are aimed at matching bout widths and keeping straight lines, and can help even the most skilled operators work more efficiently.
Farm Works based at Kippen, Perthshire, offers the Outback S GPS guidance system, which comprises a steering guide and a GPS antenna/receiver. The system is portable and can be swapped from tractor to tractor as required.
"The Outback steering guide allows operators to make full use of working widths and carefully match bouts when striking out a field to be mown, or cultivating at night," says Vince Dempsey, Farm Works agricultural sales director. "The applications for using this type of equipment for field work are endless, and it is a system that does not require permanent installation in any one tractor. It will even provide straight line guidance over rolling countryside, where you cant see the field boundary."
The Outback system relies on a satellite signal to locate its position and Mr Dempsey adds that customers do not have to sign up to a full years subscription to receive a signal, a limited number of hours can be bought from Farm Works to suit the workload.
Mounted to the dashboard or windscreen just behind the steering wheel, the steering guide uses two rows of lights to indicate current and projected driving positions. Any deviation or change of course is shown on a row of coloured lights above the indicated current position, and the operator simply steers towards the lights to maintain the desired course.
Operators can choose from straight guidance or contour guidance modes. The former provides parallel passes spaced exactly to the chosen working width of the implement, while contour guidance allows the system to provide matched passes based on the shape of a headland. Accuracy of the system is claimed to be within 10-15cm.
"It is easy to lose sight of bout marks at night regardless of the efforts made," he says. "The Outback guidance system will keep working widths right on target." The system costs from £2950.
LH Agro offers the EZ-Guide Lightbar and Swath XL systems; the former is for straight parallel lines, the latter for contoured parallel lines, and the firm says the lightbar can be added to its LH665 precision farming system.
RDS Technology provides the Marker, a differential GPS (DGPS) guidance system aimed at helping operators to drive straight and accurately, while providing equally spaced bouts.
But instead of using LEDs to guide the operator on a given course, the RDS Marker uses a real-time moving bout width, on screen. "Our system offers parallel, straight-line marking, and it can be added to an existing GPS package," explains Peter Nelson of RDS. "For those with an existing receiver, the Marker costs £2200, or it can be supplied as a complete system with a GPS receiver for £4700."
John Deeres Parallel Tracking system is another development that uses an in-cab screen to show the position of the tractor. Deere achieves this by displaying the bonnet and front axle of the tractor on the screen, with the desired course indicated by a straight line running through the middle of the tractor on the display.
"Parallel Tracking is an entry-level GPS package that can put farmers on the first rung of the precision farming ladder," says Jonathan Henry, John Deeres AMS specialist. "Had such a system been one of the first developments to come out of the GPS revolution all those years ago, then I believe more farmers would now be involved with precision farming, and perhaps making the next steps towards better management of in-field variations."
John Deeres system offers only straight-line guidance but a prototype system with automated steering – to be called AutoTrac – is already working in North America and is scheduled to reach the UK later this year. "It is our conclusion that a contour guidance aid is of little value without automatic steering," he adds.
Customers already using John Deeres Greenstar precision farming system can add Parallel Tracking components to it, while a complete Parallel Tracking system with 12 months subscription to a GPS correction signal, costs about £6000.
Automated steering is already available from the Precision Agricultural Systems division of Trimble Navigation. Called AgGPS Autopilot, it plumbs into the tractors steering system to make row-correction manoeuvres on behalf of the operator.
With hands-free operation, says Trimble, the driver can then focus on implement controls for cultivating and bed preparation. The system can be disengaged at any time by moving the steering wheel to resume manual control. Trimbles AgGPS Autopilot system costs from £25,000.
Renaults prototype Tractosat system, which is expected to come on to the market in 2003, also offers an automatic guidance function. Using differential GPS, Tractosat can be used to automatically steer the tractor in the field, leaving the driver free to concentrate on managing the implement.
By first driving around the field, the operator plots a boundary into the Tractosat GPS. The operator then enters the working width of the implement and the desired headland width. Using this information from any starting point on the headland, Tractosat then takes over the steering function, guiding the tractor up the field. At the headland, the system then turns the tractor around and realigns it on the headland to make the next adjacent pass down the field. Renault claims the system is accurate to within 5cm between each bout.
Ultimately Renault is looking to develop Tractosat to carry out automatic job sequences, which can be repeated in future. It is, in effect, creating a cloned operation.
Renault says the system will remember engine speeds, what gear was selected and when, and exactly when the lift arms were raised and lowered. Then, whenever that operation is subsequently carried out in the same field, the press of a button will see Tractosat automatically control the tractor and carry out an exact replica of the previous operation. *
Trimbles AgGPS Autopilot plumbs into the tractors steering system to make row-correction manoeuvres.
Renaults prototype Tractosat system is expected to be available next year.
Parallel tracking from John Deere is a straight line driving aid.
RDSs Marker system uses an in-cab screen to display in-field location.