Static Measurement of the Centre of Gravity Height on Narrow-track Agricultural Tractors

Abstract

According to the European Community (EC) and Organisation for Economic Co-operation and Development (OECD) Codes, narrow-track agricultural tractors have to pass a lateral stability and a non-continuous rolling test. This second test requires the knowledge of the centre of gravity (CG) height. Generally the CG height is determined by a dynamic procedure making the tractor oscillate on a platform, and measuring its period for different lengths of suspension. The dynamic procedure is rather complex and the precision of the measurements was not sufficient to fully comply with the Codes. As a consequence an alternative method was tested, using the platform in a static way: the CG height was calculated from the equilibrium equations, with a higher precision than with the dynamic method, and with less operative difficulties. The present research, considering more than 100 tractors, indicated that difficulties remain in containing the measuring errors within inside the limit of ±3 mm requested by the Codes.