Yasser Bouzid

Energy Based 3D Autopilot for VTOL UAV Under Guidance & Navigation Constraints.

Motion control design plays a crucial role in autonomous vehicles. Mainly, these systems operate in conditions of under-actuation, which make the control a serious task especially in presence of practical constraints. The main objective within this paper is to ensure the tracking of 3D reference trajectory overcoming some of the issues related to the control of multi-rotor vehicles (such as underactuation, robustness, limited power, accuracy, overshoot, etc.). Therefore, a control scheme for Vertical Take Off and Landing (VTOL) multi-rotor Unmanned Aerial Vehicle (UAV) is designed, applying the Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC) technique. As reference model based technique, the control specifications are readily met by fixing a desired dynamic model, which is a major advantage of the technique. Moreover, a port −controlled Hamiltonian representation is exploited in order to point out the physical properties of the system such as its internal energy. This latter is exploited, as a fitness function for an optimization algorithm, in order to decrease the consumed energy especially at the take-off step and allows the tuning of the controller parameters. The numerical simulations have shown satisfactory results that support the claims using nominal system model or disturbed model. The designed controller has been implemented on a real vehicle for which one demonstrates, in an indoor area manipulation, the effectiveness of the proposed control strategy.

Two-scale geometric path planning of quadrotor with obstacle avoidance: First step toward coverage algorithm

In this paper, a quadrotor path-planning problem while avoiding obstacles, in different shapes and sizes, is considered. The quadrotor is assumed to pass by a set of scattered points or regions defined according to the desired mission following the shortest path. The problem is solved by using a two-scale proposed algorithm. In the first scale, multi-directional optimal Rapidly-exploring Random Trees (RRT) based algorithm is used to define the shortest paths from each point to its neighbors. By means of the inter-costs provides by the first-scale algorithm, in the second scale, the overall shortest path is obtained by solving the Traveling Salesman Problem (TSP) using Genetic Algorithms (GA). The effectiveness of the proposed algorithm is verified with numerical simulations.

3D autonomous navigation of quadrotor using redundant flight controllers: Comparison study

In this paper, two redundant controllers are proposed in order to boost the capabilities of the popular feedback linearization flight controller scheme. The first one is based on the sliding mode framework whilst the second one is built upon the Model Free Control (MFC) theory. An in-depth discussion is highlighted with detailed evaluation in terms of performance, consumed energy, and robustness by considering several scenarios and using several metrics. The numerical simulations have shown satisfactory results using nominal system model or disturbed model through an application to a small Vertical Take-Off and Landing (VTOL) quadrotor.

Generic dynamic modeling and robust Sliding Mode based Model-Free Control for 3D navigation of multirotor VTOL UAVs

This paper introduces a generic and accurate dynamic model, based on Newton-Euler formalism, for multirotor vehicles taking into consideration aerodynamic effects. Besides, the paper considers a reformulation of the well-known Model-Free Control (MFC), which is applied for a low-cost quadrotor even in the presence of various type disturbances, including unmodeled or neglected dynamics, parametric uncertainties, external disturbances, etc. This reformulation takes into consideration the limitation of the estimator used by the classical MFC by using a Sliding Mode auxiliary Controller (SMC) leading to SMC-MFC controller. In addition, instead of using a pure data-driven based control, we introduce the available mathematical dynamics of the system even if they are poorly known. Herein, the MFC principle is employed to deal with the unknown part of the plant only (i.e., unmodeled dynamics, disturbances, etc.). The stability of the closed-loop system is guaranteed and for which a theoretical analysis is provided. The numerical simulations have shown satisfactory results. An in-depth discussion, with respect to the control performance and consumed energy, is highlighted by considering several scenarios and using several metrics.This paper introduces a generic and accurate dynamic model, based on Newton-Euler formalism, for multirotor vehicles taking into consideration aerodynamic effects. Besides, the paper considers a reformulation of the well-known Model-Free Control (MFC), which is applied for a low-cost quadrotor even in the presence of various type disturbances, including unmodeled or neglected dynamics, parametric uncertainties, external disturbances, etc. This reformulation takes into consideration the limitation of the estimator used by the classical MFC by using a Sliding Mode auxiliary Controller (SMC) leading to SMC-MFC controller. In addition, instead of using a pure data-driven based control, we introduce the available mathematical dynamics of the system even if they are poorly known. Herein, the MFC principle is employed to deal with the unknown part of the plant only (i.e., unmodeled dynamics, disturbances, etc.). The stability of the closed-loop system is guaranteed and for which a theoretical analysis is provided. The numerical simulations have shown satisfactory results. An in-depth discussion, with respect to the control performance and consumed energy, is highlighted by considering several scenarios and using several metrics.

Sliding Modes based Nonlinear PID Controller for Quadrotor: Theory and Experiment

In this paper, a Nonlinear PID (NLPID) control design is proposed. The main idea consists of combining theclassical sliding modes approach together with the PID structure. Unlike the existing nonlinear PIDcontrollers in the literature, the coefficients are constant parameters in this work. Within this paper, weinvestigate the efficiency and the performance of this technique through an application to a small VerticalTake Off and Landing (VTOL) Unmanned Aerial Vehicle (UAV). The NLPID based autopilot drives thevehicle toward the desired configuration in the space while stabilizing the roll and the pitch angles wherethe closed-loop system stability analysis is highlighted. The numerical simulations have shown satisfactoryresults using nominal model or disturbed one compared to the use of classic sliding modes technique only.Experimental tests are performed to validate the effectiveness of the proposed control approach.

Revisited model-free controller for 3D autonomous navigation of quadrotor: Features analysis in harsh flight conditions

The performance in any flight system depends on the feedback control scheme. Therefore, in a first stage, we apply as a basis the so-called Model Free Control (MFC) for the development of nonlinear flight control law that could be implemented without much difficulty. As second step, an in-depth discussion with respect to the control performance is highlighted. Due to the novel form that we propose, we can raise the performance and the robustness level with regards to structured or unstructured uncertainties. Thus, this nonlinear control that we call Revisited-MFC (R-MFC) is compared with other strategies and in particular with the use of the basic MFC. A detailed evaluation in terms of consumed energy, accuracy and robustness by considering several scenarios and using several metrics is presented. The numerical simulations have shown satisfactory results through an application to a small Vertical Take-Off and Landing (VTOL) quadrotor.

3D trajectory tracking control of quadrotor UAV with on-line disturbance compensation

In this paper, we propose a revisited form of the so-called Model-Free Control (MFC). Herein, the MFC principle is employed to deal with the unknown part of the plant only (i.e. unmodeled dynamics, disturbances, etc.) and occurs beside an Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC) strategy that is used instead of the PID structure as done in the classical MFC form. Using the proposed formulation, it is shown that we can significantly improve the performance of the control and its robustness level. This problem is studied in the case of Multi-Inputs Multi-Outputs (MIMO) system with an application to a small Vertical Take-Off and Landing (VTOL) vehicle where a stability analysis is also provided. The numerical simulations have shown satisfactory results where an in-depth discussion with respect to the control performance is highlighted by considering several scenarios and using several metrics.

Comparative Results on 3D Navigation of Quadrotor using two Nonlinear Model based Controllers

Recently the quadrotors are being increasingly employed in both military and civilian areas where a broad range of nonlinear flight control techniques are successfully implemented. With this advancement, it has become necessary to investigate the efficiency of these flight controllers by studying theirs features and compare their performance. In this paper, the control of Unmanned Aerial Vehicle (UAV) quadrotor, using two different approaches, is presented. The first controller is Nonlinear PID (NLPID) whilst the second one is Nonlinear Internal Model Control (NLIMC) that are used for the stabilization as well as for the 3D trajectory tracking. The numerical simulations have shown satisfactory results using nominal system model or disturbed model for both of them. The obtained results are analyzed with respect to several criteria for the sake of comparison.