Adaptive control of a continuously variable transmission subject to wear

Continuously variable transmissions (CVT) require an electronic controller for real application: it must reach a targeted transmission speed ratio in spite of wear. Based on our recent model based for high speed steel belt CVT, an improved feedback linearization design is proposed with an on-line adaption of the main nonlinear map in a neural associative memory. The adaptation is required because the stability condition depends of the accuracy of the estimated nonlinear map. Experimental results show that the adaptation allows the speed ratio controller to remain stable regardless of the wear accumulated by the CVT transmission.