Toufik Souanef

• Doctor of Engineering
• Lecturer in Avionics at Cranfield University

This paper presents an L1 adaptive controller for systems with disturbances of unknown bounds. The estimation laws borrows insights from the sliding mode control to estimate the unknown bounds of disturbances. Simulation results are provided to show the benefits of the presented control scheme.

This paper proposes a method for fault tolerant control. The design is based on an L1 adaptive controller with a nominal reference model and a set of degraded reference models. In a degraded model the criteria of stability margins and performance bounds are reduced. The simulation results, for the altitude hold control of a small fixed-wing UAV, sh...

This paper proposes an ℒ1 fuzzy adaptive controller for a class of uncertain continuous-time single-input single-output nonaffine nonlinear systems. The structure of this controller is derived based on ℒ1 adaptive control design methodology and integrates a fuzzy system. The latter is used to approximate as best as possible a function of an unknown...

Lectures notes on optimal control

Small UAVs are very sensitive to wind. Furthermore, they are generally built with low-cost material which makes them prone to frequent faults and failures. On the other hand, limited avionic equipment reduce the possibility to elaborate and implement complicated guidance and control systems. All these reasons motivate the use of a control method th...

This paper presents an adaptive fault-tolerant control strategy tailored for fixed-wing unmanned aerial vehicles (UAV) operating under adverse conditions such as icing. Using radial basis function neural networks and nonlinear dynamic inversion, the proposed framework effectively handles simultaneous actuator and sensor faults with arbitrary nonlin...

Reducing landing kinetic energy during emergency landings is critical for minimising occupant injury in eVTOL aircraft. This study presents the development of an autonomous parafoil control system for impact point targeting and flare control. A model predictive controller for a six-degree-of-freedom parafoil and eVTOL payload model was designed inc...

This paper introduces a stable adaptive PID-like control scheme for quadrotor Unmanned Aerial Vehicle (UAV) systems. The PID-like controller is designed to closely estimate an ideal controller to meet specific control objectives, with its gains being dynamically adjusted through a stable adaptation process. The adaptation process aims to reduce the...

This paper presents a guidance and control system for controlling the trajectory of a stratospheric unmanned airship using a cascaded Incremental Nonlinear Dynamic Inversion (INDI) method. The control system uses a two-loop cascaded INDI controller with virtual efforts and moments formulation to control both the airship attitude and velocity, while...

A new approach for output feedback L1 adaptive control based on a proportional adaptation law is presented. The effectiveness of this design is assessed in simulation and validated through real-time testing on an airfoil pitch control wind tunnel experimental rig. Experimental evaluation of the robustness of the controllers, assessed by introducing...

As the utilization of stratospheric airships becomes more prevalent, ensuring their safe operation becomes crucial. This paper explores the ability of an L1 adaptive controller to maintain fault tolerance in the actuators of a stratospheric airship. L1 adaptive control offers fast adaptation while separating adaptation and robustness. This makes th...

This paper presents a method for fault-tolerant control of small fixed-wing unmanned aerial vehicles (UAVs). The proposed design is based on multiple-model L1 adaptive control. The controller is composed of a nominal reference model and a set of suboptimal reference models. The nominal model is the one with desired dynamics that are optimal regardi...

This paper presents a method for fault tolerant control of quadrotor UAVs in case of inversion of the torque direction, a situation that might occur due to structural, hardware or software issues. The proposed design is based on multiple-model ℒ1 adaptive control. The controller is composed of a nominal reference model and a set of degraded referen...

The UK aviation industry is committed to achieving net zero emissions by 2050 through sustainable measures and one of the key aspects of this effort is the implementation of Unmanned Traffic Management (UTM) systems. These UTM systems play a crucial role in enabling the safe and efficient integration of unmanned aerial vehicles (UAVs) into the airs...

This paper proposes an adaptive, three dimensional (3D) path-following controller for airships in the presence of wind disturbances, which explicitly considers that wind speed is time-varying. The main idea is to formulate airship path-following as control design for systems in the presence of parametric uncertainties and external disturbances. Ass...

An approach for output feedback L1 adaptive control of small Unmanned Aerial Vehicles (UAVs) is presented in this paper. The design is based on a state observer instead of the state predictor. The main advantage is that a full state measurement can be avoided, and the design and implementation of the controller are simplified. Furthermore, since...

This paper presents the design of a digital twin that blends aviation, gaming, simulation, and Geographic Information Systems (GIS) to create a synthetic environment within which strategies, laws and platforms for electric aviation may be tested out. This digital twin has been called Future Urban Synthetic Environment (FUSE). FUSE includes an in-bu...

This paper proposes an adaptive path-following controller of small fixed-wing Unmanned Aerial Vehicles (UAVs) in the presence of wind disturbances, which explicitly considers that wind speed is time-varying. The main idea was to formulate UAVs path-following as control design for systems with parametric uncertainties and external disturbances. Assu...

In a recent paper by Ortega et al. (2013), some comments were made on L1 adaptive control Cao et al. (2010), and the primary result was that the condition of stability suggested in the literature can not be "verifi�ed." The objective of this paper is to show that this statement is based on an assumption that arti�ficially restricts the potential of...

In a recent paper by Ortega et al. (2013), some comments were made on L1 adaptive control, and the primary result was that "the condition of stability suggested in the literature can not be verified." The objective of this paper is to show that this statement is based on an assumption that artificially restricts the potential of L1 adaptive contro...

A new approach for output feedback L1 adaptive control is presented in this paper. The design is based on a state observer instead of the state predictor. The main advantage is that a full state measurement can be avoided, and the design and the implementation of the controller is simplified. Since a state space description is maintained, the syste...

In this paper an altitude hold controller of a small fixed wing UAV is presented, designed with output feedback L1 adaptive control with switching adaptation law. The adaptive architecture is based on the estimated state as a substitute of full state knowledge. Simulation results on a real-time test bench show robustness of the adaptive controller...

In this paper an altitude hold controller of a small fixed wing UAV is presented, designed with output feedback L1 adaptive control with switching adaptation law. The adaptive architecture is based on the estimated state as a substitute of full state knowledge. Simulation results on a real-time test bench show robustness of the adaptive controller...

This paper presents a stochastic state feedback L1 adaptive control for systems with matched disturbances. The proposed approach is characterized through the introduction of a Kalman type fixed gain in the predictor. The main contribution of this work is that closed loop system analysis is demonstrated through a deterministic-like approach that use...

In this paper an altitude hold controller of a small fixed wing UAV is presented, designed with output feedback L1 adaptive control with switching adaptation law. The adaptive architecture is based on the estimated state as a substitute of full state knowledge. Simulation results on a real-time test bench show robustness of the adaptive controller...