Development of automated turf testing equipment for playing surfaces

Development of automated turf testing equipment for playing surfaces

[Abstract]: Research has shown that a significant percentage of sporting injuries can be attributed to the sporting surface. The most serious of these injuries require surgery, for example, to correct knee ligament damage, a condition which involves expensive procedures and lengthy post-operative rehabilitation. The responsibility for meeting the costs of these injuries is not restricted to the player or the team; there is an unnecessary burden on society in terms of overtaxing an already encumbered health system.

A correlation between knee injuries and the traction properties of the sporting surface has been identified by Dr John Orchard, a recognised expert in Australia for sporting injuries. Turf traction referred to in this thesis is a term relating to the shoe and sporting surface interface and reflects the maximum amount of torque a studded sporting shoe can impart on the surface before the integrity of the surface is compromised. Current equipment to measure turf traction properties has limited accuracy and repeatability. This thesis reports the development of a device which measures turf traction with improved accuracy, repeatability and operator safety in comparison with existing commercially-available equipment.

The design described in this thesis comprises a rotating ground-engaging ‘foot’ driven by a DC motor to provide the required torque for traction measurement, and this torque is continuously monitored using a load cell via an idler sprocket in the drive train. A digital load indicator displays and transmits torque data, and a programmable controller automates the test sequence. A permanently-installed laptop computer analyses, displays and records the traction data. The mechanical design includes a chassis which provides convenient movement across a playing surface and also convenient transport between sporting surfaces.

The design automates only those measurement processes that require a high degree of accuracy and repeatability. Non-critical actions are operated manually to maximise simplicity and minimise development costs. Commercially available technology is used wherever possible within the design to eliminate specialist maintenance skills or knowledge. Software was developed to analyse, display and record the traction data and produce a traction profile which is unique for this type of equipment. A full patent has been granted on the device (encompassing function, design and performance) to facilitate commercial development by the Queensland Department of Primary Industries and Fisheries.

An evaluation of the accuracy and repeatability of this machine is described and several experiments were undertaken to analyse its ability to compare and differentiate turf species from the traction results. For torque measurements within the expected operating range of 50 to 100 Nm a maximum error of ±1.28% has been established.

It is demonstrated that the device meets the design objectives of accuracy, repeatability and operational safety. It has been used within a national Horticulture Australia project to determine best practices for sustainable and safe playing surface of Australian Football League sports fields.