Factors Affecting the Accuracy of Weighbridge Systems
Authors
Hamish Marshall
University of Southampton
Glen Murphy
Oregon State University
Abstract
The average log size in many parts of the world is getting smaller and it is becoming increasingly time consuming and expensive to individually scale each log. Truck scaling of various forms, including the use of weighbridges, is becoming increasingly popular.
Understanding the factors affecting the accuracy of weighbridge systems is vital if measurement errors are to be minimized. We used a mixture of interviews with weighbridge operators, suppliers and government weights and measures staff in New Zealand along with experiments on a small set of weighbridges to identify, and where possible quantify, the most important factors affecting weighbridge accuracy. In our paper we have broken down the sources of variation into mechanical, environmental, truck, human and system-related. It is difficult to put a figure on the possible magnitude of these combined sources of variation, however, interviews, experiments and calculations show that it could be as much as 4% of the payload weight - although it is likely that some sources of variation will act in opposite directions and cancel each other out.
