The Terrier Maneuvre Support Vehicle uses multiple hydraulic cylinders with Hall-effect linear displacement transducers to provide electronic position feedback. Because they cost considerably less than other types of LDTs, the hall-effect LDTs can be incorporated into multiple cylinders, not just the most critical ones.
The FV180 Combat Engineer Tractor, designed by BAE Systems, Farnborough, UK, has become the standard vehicle of its class in the British Army. More recently, BAE Systems was awarded a contract for the design, development, and production of the more-capable Terrier Maneuvre Support Vehicle (MSV). MSVs can undertake a much wider range of battlefield operations than today’s FV180 CET, which was originally conceived more than 30 years ago.
The first prototype of Terrier was rolled out at the Land Systems Leicester facility in mid-2005 and has since been engaged in a demanding series of trials at various locations in the UK. BAE Systems built four pre-series Terriers in 2007, and about 65 production vehicles will follow — with the first batch of 20 to be delivered by late 2009.
What it is
Terrier is a tracked vehicle fitted with a front-mounted, hydraulically operated bucket that can be used to clear obstacles, prepare vehicle and weapon pits, and grip large objects. A ripper can be fitted to break up road surfaces.
Mounted on the right side is a hydraulically operated excavator arm system that can lift a maximum of 3 tons at full reach. Normally fitted with a bucket, the arm can be used to prepare infantry trenches. However, the bucket can be replaced quickly by other specialized attachments, such as an auger that can drill holes to 3-m deep, or an impact hammer-breaker. A rear load platform can carry payloads to 5 tons.
Despite all this versatile tooling, the Terrier is light enough to be carried in an A400M aircraft, and two can be carried in a C-17 aircraft.
An electronic interface
A key element of the Terrier’s success is electronic control, and to interface with electronics, hydraulic cylinders require some sort of linear displacement transducer (LDT). Magnetostrictive transducers have gained widespread use as an LDT, especially in stationary applications. High production machines that require positioning accuracy to within thousandths of an inch justify the cost of a magnetostrictive LDT.
However, Mark Hoffman, of Rota Engineering, Dallas, points out that because mobile equipment has a human operator, position feedback from cylinders generally only needs to be within hundredths of an inch. Put simply, he says that magnetostrictive LDTs are overkill for most mobile equipment applications. He suggests that an LDT with slightly less precision, but substantially lower cost, would enable designers to provide cylinder position feedback more often — not just for the most critical applications that justify high cost.
