Optimal control methods with application to aerospace systems

Lead Research Organisation: University of Oxford
Department Name: Engineering Science

Abstract

The project will explore optimal control design and optimisation methods for aerospace systems, among which fixed-wing aircraft, VTOL aircraft and spacecraft.
Initially the focus will be the design and optimal control of hybrid electric propulsion systems for aircraft. This work will build on existing convex formulations of energy management problems for hybrid vehicles, with extensions to account for the aircraft dynamics, time-varying aircraft weight and additional constraints on gas turbine operation during flight. The framework for optimizing energy management will subsequently be used to consider the design of powertrain components and flight paths. The main objectives for this part of the project will be the development of a computationally tractable optimization for minimizing fuel consumption along a pre-specified flight path, and the optimization of hybrid prowertrains in aero-propulsion applications.

The convex framework developed above will also be applied to solve the energy management problem for a spacecraft with various energy sources (battery, solar panels, etc.) and subject to dynamical and thermal constraints. The goal is to permit energy efficient unmanned operation of the spacecraft during its mission, while maintaining the various subsystems into safe working ranges.

Another research direction to be considered by the project is the development of constrained controllers for VTOL aircraft in order to follow specified flight paths. Hybrid dynamical systems are challenging to control as the dynamics change along different operating trajectories, they are subject to transient behaviors and control allocation to the actuators is critical during transitions. Vertical takeoff and landing (VTOL) aircraft, which are capable of transitions from hover to forward flight, are examples of such hybrid systems. Recently developed VTOL aircraft thus introduce new challenges in terms of modelling and control. On the one hand, modelling requires a multi-body analysis via a constrained Lagrange formalism for the coupling mechanism. Complex aerodynamics also arise from the interaction between the aircraft and rotating parts. Other nonlinearities include blade flapping, total thrust variation, ground effect during landing/takeoff and widely varing lift and drag cofficients. To account for constraints and nonlinear dynamics, a model predictive control (MPC) approach will be adopted, which combines convex optimization and tube MPC to develop a provably safe controller robust to external disturbances. The project will provide a better understanding of an aircraft design that provides excellent opportunities for short flights. The control and energy management techniques developed over the course of the project will enable this aircraft to be used safely in a commercial capacity.

This project falls within the EPSRC Engineering (Control engineering) research area.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R513295/1 01/10/2018 30/09/2023
2290940 Studentship EP/R513295/1 01/10/2019 31/03/2023 Martin Emile Doff-Sotta