Model Identification and Control of a Convertible Aircraft – MICA

An initial problem that will be addressed during this project is the modelling of aerodynamic phenomena. This is an essential issue that has to be solved before designing autonomous pilots. We will consider three phases of flight: (a) hover (or stationary) flight, (b) fast forward flight, and (c) transition from hover to fast forward flight (and vice versa). While significant research has been done in the modelling in phases (a) (for conventional multi-copters) and (b) (for conventional air planes) there are very few results describing modelling in phase (c). However, this is a very important aspect in our project and we will address it in an initial phase of the project.
The goal being that the convertible aircraft be capable of flying without human pilot intervention from a point A on the map to a point B on a given trajectory (which minimizes energy consumption), in a second phase of this project, we will work on the design of fault tolerant trajectory tracking algorithms. An important aspect of autonomous flight is safety. Under no condition the convertible aircraft should pose a security risk for people, other aircraft or itself. That is why during this project phase we intend to work on the design of fault tolerant control algorithms. With respect to the trajectory planning, an important aspect is conversion from stationary to fast forward flight with minimum dispense of energy.
To complete the fault tolerant control design in this project, fault detection algorithms shall be investigated as well. Among possible defects, we will consider the loss of actuators (propeller rotors) or sensors (inertial measurement units).

A first result during this project has shown the a mathematical model of a convertible aircraft is flat.

We are currently working on constructing a delta wing that will serve as experimental test-bench for our algorithms.

Conference papers:
1. Tudor-Bogdan Airimitoaie, Gemma Prieto Aguilar, Loïc Lavigne, Christophe Farges, and Franck Cazaurang, Convertible aircraft dynamic modelling and flatness analysis, 9th Vienna International Conference on Mathematical Modelling, Vienna, Austria, February 21 – 23, 2018.
2. Tudor-Bogdan Airimitoaie, Loïc Lavigne, Christophe Farges, Kelly Cohen, and Franck Cazaurang, Model Identification and control of a Convertible Aircraft (MICA). ANR young researcher program, AIAA 42nd Dayton-Cincinnati Aerospace Sciences Symposium, Sinclair Conference Center, Downtown Dayton, March 1, 2017.

It is clear that the impact of the human civilization on the environment should be reduced in the following decades in order to preserve the environment. It is neither ecological nor sustainable to continue using natural resources as it is done at present. An important part (almost a third) of the worldwide energy consumption is dedicated to transportation. It is our opinion that one solution to reduce the energy consumed this way and limit environmental damages is to develop new concepts of transportation systems.

Within this project, we will focus on the concept of convertible aircraft, with emphasis on the design of autonomous fault tolerant trajectory tracking control algorithms. A convertible aircraft, as considered in this project, denotes a flying machine capable of vertical take-off and landing (VTOL), such as a multi-copter, but which behaves as a regular air plane during cruise flight. To accomplish this, all convertible aircraft have wings. VTOL can be realized either with thrust vectoring engines or with propeller rotors. The concept convertible aircraft that we intend to use for experimental validation shall be equipped with propeller rotors.

Integrating these aircraft in spaces with high population density requires that a certain level of safety be guaranteed, in particular during phases of take-off and landing. It is therefore necessary to implement trajectory control systems that are robust to disturbances, fault tolerant, and capable to generate last resort rescue trajectories ensuring safety for people and habitations. This project aims to contribute to these expectations with the realization of a technological brick capable of running and maintaining the convertible on security transition paths (in nominal and emergency paths) and thus meet future national and international aerial regulations.

An initial problem that will be addressed during this project is the modelling of aerodynamic phenomena. This is an essential issue that has to be solved before designing autonomous pilots. We will consider three phases of flight: (a) hover (or stationary) flight, (b) fast forward flight, and (c) transition from hover to fast forward flight (and vice versa). While significant research has been done in the modelling in phases (a) (for conventional multi-copters) and (b) (for conventional air planes) there are very few results describing modelling in phase (c). However, this is a very important aspect in our project and we will address it in an initial phase of the project.

The goal being that the convertible aircraft be capable of flying without human pilot intervention from a point A on the map to a point B on a given trajectory (which minimizes energy consumption), in a second phase of this project, we will work on the design of fault tolerant trajectory tracking algorithms. An important aspect of autonomous flight is safety. Under no condition the convertible aircraft should pose a security risk for people, other aircraft or itself. That is why during this project phase we intend to work on the design of fault tolerant control algorithms. With respect to the trajectory planning, an important aspect is conversion from stationary to fast forward flight with minimum dispense of energy.

To complete the fault tolerant control design in this project, fault detection algorithms shall be investigated as well. Among possible defects, we will consider the loss of actuators (propeller rotors) or sensors (inertial measurement units).

An experimental platform should be used to validate algorithms proposed during this project. Two solutions are considered at this point. The first is to build our own convertible aircraft; the second is to buy one provided that sufficient support would be offered by the manufacturer. Actuator and sensor redundancy in this platform should allow testing different types of defects.