Off-Road Dynamics Facility

Resource, Nov 2005 by Godwin, Dick, Brighton, James

New at Cranfield University at Silsoe

A number of international agricultural, aerospace, automotive, construction, defense, marine communications, and tire companies are in discussion with Cranfield University after presenting plans for a $2 million off-road machine dynamics facility at Silsoe in Bedfordshire, United Kingdom. The new facility will enable assistance to these companies with research projects as well as test and evaluation programs and equipment, vehicle, and tire development in different soil conditions. These range from friable agricultural soil for tractors and tillage tools, loose dry sands for the performance of sports utility vehicles in desert conditions, dense compact soils to support airplane landing gear, to submerged saturated sands for sub-sea telecommunications cable laying plows.

The Higher Education Funding Council for England (HEFCE) provided 90 percent of the funding with a further and critical commercial contribution of 10 percent from Land Rover with further in-kind support from several international manufacturers including case New Holland, Deutz, Global Marine Systems, and QinetiQ.

The construction of the laboratory started in April and is being finalized. The soil preparation and the initial mechanical rigs should be completed by the first quarter of next year for an official launch in May 2006.

Building on past successes

The new facility complements the existing 20 m (65.6 ft) long, 1.75 m (5.7 ft) wide, and 0.8 m (2.6 ft) deep soil dynamics laboratory which has proved to be very successful for more than 20 years for many PhD student projects and commercial research, helping to develop the wide furrow moldboard plow for Kverneland, the Solo cultivator for Simba, a shallow slurry injector for Greentrac, the Going Stick for evaluating the "going" at racecourses for Turftrax, aspects of tillage train development for Vaderstad, the new traction control systems for Land Rover, mobility strategies for defense vehicles, and sub-sea cable laying and recovery plows for Global Marine Systems. Work in this soil bin is currently studying:

* the effects of surface loads on buried archeology,

* the development of combined inter- and intra-row mechanical weeding equipment,

* a comparison of the relative effects of tire and track systems on soil compaction,

* techniques for the improved performance of sports (cricket) pitches, and will continue to be used where very precise control on soil density with depth is required.

The new facility is required to enable the work to expand on the performance of full-size vehicles in controlled soil conditions as there are obvious limitations in the existing soil bin. The new soil lane will be complemented by other rigs to determine the performance of off-road vehicles and tire systems.

Ramping up with new features

The soil lane in the new facility is 5 m (16.4 ft) wide, 45 m (147.6 ft) long, (35 m (114.8 ft) at 0.75 m (2.5 ft) deep, and 10 m (32.8 ft) at 1.5 m (4.9 ft) deep. It includes the capability to control the water level to simulate a range of conditions from the saturated sea-bed encountered in sub-sea cable laying to hard compact dirt roads and airstrips. A sophisticated, single-wheel test apparatus, designed to accurately control the torque, slip, and wheel load of a single test wheel in almost any environment, will measure tire performance and the effectiveness of different traction control and load control techniques, while a variable plane four-wheel traction plate can simulate undulating ground surfaces.

Key features of the laboratory include:

* an integrated vehicle load control system for the simulation of practical vehicle loads,

* two test rigs for the evaluation of single wheel or track system performance, able to operate within the facility or an external environment,

* a traction plate for the evaluation of static tire loads and contact patch characteristics across a range of longitudinal and lateral vehicle articulations, and

* instrumentation systems for the measurement of machine performance and environmental impact.

These research rigs are currently being designed by our colleagues and will meet the requirements of a range of industries including agriculture, automotive, and motor sport industries for the provision of previously unavailable tire data.

One of the long-term research aims is to create a precise simulation or virtual environment for the evaluation of any machine or vehicle configuration in a controlled manner. This will improve the accuracy, repeatability, and costeffectiveness of tire and vehicle dynamics research for offroad vehicles and equipment.

Late, breaking news

Since preparing this feature, the authors announce that Cranfield University at Silsoe has just received confirmation for a further $1.3 million to enable the development of the rigs.

ASABE fellow Richard (Dick) Godwin, F.R.Eng., C.Eng., is professor of agricultural engineering and head of engineering in the National Soil Resources Institute, Cranfield University at Silsoe, Silsoe, Bedford, MK45 4DT, United Kingdom; 44 1525 863053, fax 44 1525 863366, r.godwin9cranfield.ac.united kingdom.