Error analysis and data forecast in the centre of gravity measurement system for small tractors

A novel centre of gravity measurement system for small tractors with the principle of the three-point reaction is presented. According to the prototype of a small tractor gravity centre test platform, a mathematic multi-body dynamics prototype was built to analyze the measurement error in the centre of gravity measurement system. For the precision evaluation, interrelationships among the factors were studied which included the test platform structural parameters, the error of measurement sensors and the displacement of drive-pillar and the mass of measurement object. In succession, a virtual collaborative model of the centre of gravity measurement system was built and verified by a real prototype-based measurement platform. A modified gray model GM(1,1), which was used for forecasting the gravity height of small tractors, was proposed to avoid deviation of test data and so improved the measurement accuracy. A series of standard test object experiments were carried out, and the results showed that the relative error of the gravity height was up to 0.93%