Rogelio Lozano

Bio: Rogelio Lozano is an academic researcher from University of Technology of Compiègne. The author has contributed to research in topics: Control theory & Adaptive control. The author has an hindex of 58, co-authored 496 publications receiving 14570 citations. Previous affiliations of Rogelio Lozano include University of Illinois at Urbana–Champaign & Instituto Politécnico Nacional.

The Transition Phase of a Gun-Launched Micro Air Vehicle

Abstract: The present paper addresses the transition stage of a Gun-Launched Micro Air Vehicle (GLMAV) whose main goal is to rapidly position a rotorcraft MAV over a high-risk scene (Prison riots, blind zones: e.g. over-the-hill, etc.). The development of this robotic platform is part of an overall ongoing project (GLMAV) headed by the St. Louis French- German Research Institute (ISL). The vehicle is launched at a distance of 500 m and a height of 100 m, where the GLMAV will collect and transmit visual information from the scene. Issues raising from the use of the gun-based launching technique are discussed in detail. A control strategy is proposed to overcome such problems and to stabilize the GLMAV. High- fidelity simulations, covering ballistic and transition phases, validate the control policy adopted to face the MAV gun- launching problem.

Energy based control for a quadrotor using unit quaternions

Abstract: This paper presents the design and simulation of an energy-based control strategy to stabilize a quadrotor described with unit quaternions and their axis-angle representation. The mathematical model is based on Euler-Lagrange formulation using a logarithmic mapping in the quaternion space. The proposed solution introduces a new approach: a quaternion-energy-based control, which introduces an energy expression defined as a Lyapunov function. The designed control law allows the stabilization of the vehicle in all its states. Simulation results and an experimental validation are presented to corroborate the effectiveness of the proposed strategy.

Outdoor haptic teleoperation of a hexarotor UAV

Abstract: This paper considers the design and control of a Remotely Operated Aerial System Remotely Operated (ROAS) with force feedback to pilot in order to increase the perception level. The force experienced by the pilot through a Human Machine Interface (HMI) considers and it is proportional to the translational speed and proximity to objects located in the environment where the UAV evolves. In order to test the performance and feasibility of the developed platform and control strategy, experimental tests have been carried out indoor and outdoor which represent a contribution in the current literature on the subject. Experimental results obtained show an acceptable performance for both flight conditions.

Stability Analysis for a Force Augmenting Device Considering Delays in the Human Model

Abstract: This paper presents a stability analysis of the interaction between a human and a linear moving Force Augmenting Device (FAD). The analysis employs the mathematical models of the human, the FAD and their interaction. As a depart from past works, this article presents a stability analysis considering time-delays in the human model. A key ingredient in the analysis is the use of the Rekasius substitution for replacing the time-delay terms. It is proved that the human machine interaction is stable when the human model has no delays. The analysis provides an upper bound for the time-delays preserving a stable interaction. Numerical simulations allow to assess the human-FAD interaction. An experiment is performed with a laboratory prototype, where a human operator lifts a load. It is observed that the human machine interaction is stable and the human operator is able to move the load to its desired position by experiencing very little effort.

Fast adaptive control of a 3-DOF inertial stabilised platforms based on quaternions

Abstract: Inertial Stabilised Platform, better known as gimbal are becoming increasingly popular, with a large range of products now available in mainstream shops. Most of these items are nonetheless controlled using very basic algorithms that do not offer best achievable performances. First, each axis is controlled independently of one another. Then, they make use of trigonometry for their calculation. Lastly, their behaviour depends on the type of payload or on the orientation of this latter. Present paper proposes an advanced control which aims at solving these classic control issues without requiring as much computational power. It is based on quaternion representation and self-adapts to the characteristics of the payload it stabilises. Although only simulation could be performed to check the performances of such control, results look very promising and may help to construct more polyvalent and efficient gimbals which would further facilitate their expansion.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Higher-order sliding modes, differentiation and output-feedback control

Abstract: Being a motion on a discontinuity set of a dynamic system, sliding mode is used to keep accurately a given constraint and features theoretically-infinite-frequency switching. Standard sliding modes provide for finite-time convergence, precise keeping of the constraint and robustness with respect to internal and external disturbances. Yet the relative degree of the constraint has to be 1 and a dangerous chattering effect is possible. Higher-order sliding modes preserve or generalize the main properties of the standard sliding mode and remove the above restrictions. r-Sliding mode realization provides for up to the rth order of sliding precision with respect to the sampling interval compared with the first order of the standard sliding mode. Such controllers require higher-order real-time derivatives of the outputs to be available. The lacking information is achieved by means of proposed arbitrary-order robust exact differentiators with finite-time convergence. These differentiators feature optimal asymptot...

Linear systems

Abstract: Most of the signal processing that we will study in this course involves local operations on a signal, namely transforming the signal by applying linear combinations of values in the neighborhood of each sample point. You are familiar with such operations from Calculus, namely, taking derivatives and you are also familiar with this from optics namely blurring a signal. We will be looking at sampled signals only. Let's start with a few basic examples. Local difference Suppose we have a 1D image and we take the local difference of intensities, DI(x) = 1 2 (I(x + 1) − I(x − 1)) which give a discrete approximation to a partial derivative. (We compute this for each x in the image.) What is the effect of such a transformation? One key idea is that such a derivative would be useful for marking positions where the intensity changes. Such a change is called an edge. It is important to detect edges in images because they often mark locations at which object properties change. These can include changes in illumination along a surface due to a shadow boundary, or a material (pigment) change, or a change in depth as when one object ends and another begins. The computational problem of finding intensity edges in images is called edge detection. We could look for positions at which DI(x) has a large negative or positive value. Large positive values indicate an edge that goes from low to high intensity, and large negative values indicate an edge that goes from high to low intensity. Example Suppose the image consists of a single (slightly sloped) edge: