Research on Integrated Control Method of Tiltrotor with Variable Rotor Speed Based on Two-Speed Gearbox

Abstract

The process of rotor speed variation under tiltrotor cruise state has been studied, and the integrated variable speed control method of tiltrotor based on two-speed gearbox is proposed. Firstly, a nonlinear model predictive controller (NMPC) based on state variable model of the component-level model of the turboshaft engine is designed. Then based on the integrated engine model, the two-speed dual path tiltrotor driveline comprehensive simulation model was developed by utilizing gear kinematics theory, blade element analysis and the theory of classical mechanics. Finally, both a Parallel Shift Control (PSC) strategy and a Sequential Shift Control (SSC) strategy in tiltrotor cruise state were analyzed and compared with conventional PID controller. It is shown that the rotors’ speed can synchronously vary by 50 percent under the PSC strategy in tiltrotor cruise state. Meanwhile, disengaging the engine in turn by freewheel clutches can reduce the rotors’ speed from 190 rpm to 102.5 rpm along the specified path under the SSC strategy. The overshoot and droop amount of the power turbine speed can be reduced to less than 1.5 % with the steady error no more than 0.2 % through NMPC, which realizes the fast response control of the turboshaft engine.

Design and Optimization of Low Impact Shift Control Strategy for Aviation Transmission Power System Based on Response Surface Methodology

“…The aforementioned studies primarily consider a scenario with a constant rotor speed. In such situations, a minor range of rotor speed variations results in limited changes in engine torque demand [19]. However, when there is a broad variation in rotor speed, the torque required by the main rotor and the engine's output torque must be aligned using variable transmission.…”

Aero-engine direct thrust control with nonlinear model predictive control based on linearized deep neural network predictor

“…The MPC, 5 which systematically addresses the problem of multiple objectives with constraints on engine inputs and states, has the better transient performance than the traditional controller and has aroused many aero-engine control researchers interest. 8–19 Van Essen et al 10,11 implement nonlinear model predictive control (NMPC) to a laboratory gas turbine installation and assess the feasibility (stability, real-time performance, robustness) of NMPC. Brunell et al 12 investigate the feasibility of constrained NMPC with simplified real-time model and apply it to a component-level model of turbojet engine.…”

“…16,17 The NMPC based on state variable model (SVM) is proposed and applied to integrated variable speed control of helicopter and turboshaft engine. 18 Zheng et al 19 applied NMPC for helicopter autorotation recovery maneuver to obtain better engine response speed and reduce the rotor transient droop during autorotation power recovery. The predictive models of above works are main focus on linear model especially on extended Kalman filter (EKF).…”