On Transmission-Ratio Computation for the Control of a Continously Variable Transmission in Agricultural Tractors

This paper discusses the design of the transmission-ratio control for a power-split continuously variable transmission (CVT) used in agricultural tractors. In particular, we focus on transmission ratio control, highlighting the issues related to the computation of the controlled variable in presence of significant sensor quantization errors, which are particularly significant in the power-zero condition, where the tractor has to be kept still independently of the input engine speed. The validity of the design procedure is assessed on an experimental system.