Intelligent Control Rule for Tractor with Continuously Variable Transmission

The problem considered in this paper is the design of the control rule for a tractor equipped with continuously variable transmission. In a traditional control system the optimum fuel economy or dynamic performance control rules only reflect the tractor working state, the driver´s intention is partially ignored in control system, therefore, their applications are limited in current tractors. To solve this problem, in this paper, an intelligent control rule based on fuzzy inference of driver´s intention was proposed, whose aim is to improve tractor dynamic performance under transient operating conditions and fuel economy under steady operating conditions. Using a fuzzy inference engine, the tractor dynamic factor which was introduced to indicate the driver´s demand for tractor dynamic performance based on the change and the change rate of accelerator pedal was obtained. According to the tractor dynamic factor the intelligent transient dynamic control rule can be worked out by interpolating between the fuel economy and dynamic performance control rules. After the tractor acceleration process finishes, the transition control rule was adopted to achieve the smooth transition from intelligent transient dynamic rule to steady fuel economy rule. At last, the simulation results showed that the intelligent control rule enable tractors to reach the optimum comprehensive performance. The works above provided a new design method for developing an intelligent tractor equipped with continuously variable transmission