Dynamic Simulation of a Rotorcraft Main Transmission with Continuous Variable Ratio

Abstract

The 'VARI-SPEED II' project involves TU Munich, TU Wien, Zoerkler Gears, and Advanced Drivetrain Technologies GmbH developing a drivetrain that allows variable speed of a helicopter's main rotor. This is beneficial for different speed requirements, reduced noise, and higher efficiency. Various researchers have investigated the benefits and suitable technologies for varying main rotor speed. Calculation formulas were established to find the ratio distribution of gear stages with the lowest total mass of the drivetrain, and electric variators are potential solutions. The architecture with two compound splits before the bevel gear stage was chosen for the dynamic simulation of the drivetrain due to its favorable design considerations. In the 'VARI-SPEED II' project, control of the variable speed drivetrain is crucial for achieving the desired variable main rotor speed. To achieve optimal control, a fuzzy model predictive control (FMPC) approach has been proposed. The FMPC has several advantages, including the ability to handle nonlinearities and uncertainties. Furthermore, the FMPC is real-time capital and of and can adapt to changing operating conditions.