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 ball and beam acting on the ball

Abstract: Another interesting example of underactuated systems is the ball and beam system. In this chapter, we propose a control law for the ball and beam system acting on the ball instead of the beam. Such a mechanical system is outlined in Figure 10.1 and described in Section 10.2. The system in Figure 10.1 is motivated by the control of small rotational oscillations of platforms and vehicle suspensions. For simplicity, we assume that the center of the beam is connected to the pivot using a rotational spring and we neglect friction.

Model reference adaptive control with unknown relative degree

Abstract: This work presents an indirect, model reference adaptive control for minimum phase linear systems of arbitrary relative degree. Global stability of the closed-loop system is proved in spite of bounded disturbances and asympotic tracking is achieved in the ideal case.

Estabilización de un mini helicóptero de cuatro rotores basada en flujo óptico y sensores inerciales

Abstract: This paper addresses the hover flight stabilization problems of a four-rotor rotorcraft using fusion of visual information given by a single camera and inertial information obtained from an Inertial Measurement Unit. We use the optical flow in combination with the integration of gyro measurement to estimate the linear and rotational yaw velocities as well as the position and velocity of a UAV. Experimental results show a satisfactory flight performance of the four-rotor rotorcraft platform.

PVTOL global stabilisation using a nested saturation control

Abstract: This paper presents how the nested saturation control introduced in Teel (1992) can be modified to stabilise the model of the Planar Vertical Take-Off and Landing (PVTOL) system. A particular choic...

Observer-Based Solution to the Strictly Positive Real Problem

Abstract: We study the extension of the class of linear time invariant plants that may be transformed into SPR systems introducing an observer. It is shown that for open loop stable systems a cascaded observer achieves the result. For open loop unstable systems an observer-based feedback is required to succeed. In general any stabilizable and observable system may be transformed into an SPR system using cascade or cascade and feedback controllers. This overcomes the old conditions of minimum phase and relative degree one. The result is illustrated with some examples.

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: