Simulation and control of slip in a Continuously Variable Transmission

Continuously Variable Transmissions are used to optimize engine efficiencyin automotive drivelines. The efficiency profit however, is lost due to inefficiencies inthe CVT itself. These losses occur mainly in the (hydraulic) actuation system andin the variator. The losses can be lowered by minimizing the clamping force of thepulleys on the belt. Lowering the clamping force too much also leads to heavy slippingbetween belt and pulley, causing damage to the system.By controlling the clamping force in such a way that a limited amount of slip isallowed, the clamping force can be minimized without risking damage to the system.A nonlinear control scheme is used to control slip in the variator. Results show thatsuch a control method is feasible and robust to torque peaks