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WEIGHING UP STABILITY
Page 56
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For less than £300 more than a normal truck weighing system, a new solution stops tippers
toppling. Brian Weatheriey reports.
Exclusive
While truck and trailer makers can build as much stability as possible into a tipper, when it comes to judging level ground most operators and drivers still rely on the Mark 1 Eyeball — hardly the most reliable method of risk assessment.
Commercial Motor recently looked at how inclinometers can help stop artic tippers toppling over (CM 13 May). Now vehicle weighing specialist PM Onboard has developed an electronic stability protection system that takes full advantage of its existing loadcell technology.
The system, based on its latest CAN-bus linked electronic weighing kit, goes on sale in the autumn, although the first public showing is likely to be at the Recycling and Waste Management Show at the NEC on 14,15 and 16 September.
Using loadcells to determine side tipping angles is a logical development of the technology, explains PM Onboard boss Geoff Mountain. "After 20 years working in the industry it was a natural no-brainer' for us. It's been driven out of the accuracy and information available from the latest loadcells. In the past they were fairly non-intelligent — they told you the weight applied at the point of contact. Today's are all CAN-bus driven."
Using its CAN-bus linked loadcells and a microprocessor, PM can determine a variety of stability factors, says Mountain. "Via the four points of contact on the load cells we can work out very accurately what the orientation of the vehicle is in relation to the ground."
As each loadcell detects the weight changes created by the vehicle running onto an uneven surface, the system can ultimately calculate the angle of slope it is attempting to tip on, the angle of the vehicle itself and any other ground deviations.
Like the inclinometers recently examined by CM, Mountain says the PM stability system could also include a function to prevent a driver raising the body on a tipper if it detects that it would cause instability "Through the CAN-bus it could disengage a PTO to stop a body rising further— we'll offer the option for direct intervention," confirms Mountain.
PM is currently waiting for patents on the system to be finalised. However, Mountain reports: "We've already had a good dozen units out on test for the past 18 months — there's no question as to the accuracy of the system." Basic operating parameters for the system will be initially set at PM's Bradford factory although Mountain says there will also be a "coded management function" that would allow individual operators to set their systems to match their own operating conditions and preferences for tipping on uneven ground. "Red or black marked 'values' can be stored as data in the system, allowing you to see what the driver has been doing," says Mountain. "There's no question, it's that accurate and fast and via the CAN-bus it would transmit information instantly to the screen." As more than one loadcell records weight transfer, Mountain says the system not only detects movement of the load and load distribution during discharge, it can also give an early indication via the in-cab display of an uneven or sticking load — one of the primary causes of tippers overturning.
The stability option is expected to add around £.150-£200 to the price of an on-board system which typically retails for £2,400 fully installed.Accuracy levels are claimed to be the same as PM's on board weighers at +/1%. Mountain predicts that, within 12 months: "Some 50-60% of all future on-board weighing systems on tippers will have it too.The bodybuilders and trailer makers are going to want it as the finger is often pointed at them when it comes to instability" •