Publicaciones

Autores
Orellana, A.;

Resumen:
La investigacion sobre la tecnologia de procesamiento de informacion tridimensional nos permite realizar desarrollos avanzados en un area de interes para nuestra region y nuestro paıs como es la agricultura de precision. La investigacion llevada adelante en esta tesis ha sido aplicada con exito tambien a sistemas de asistencia a la conduccion y modelado de objetos industriales, lo que da una idea de la importancia que posee el desarrollo de esta tecnologıa.

Autores
Baumgartner, J. ;Flesia, A. ;Gimenez, J. ;Pucheta, J. ;

Resumen:
Image segmentation is one of the fundamental problems in computer vision. In this work, we present a new segmentation algorithm that is based on the theory of two-dimensional hidden Markov models (2D-HMM). Unlike most 2D-HMM approaches we do not apply the Viterbi algorithm; instead we present a computationally efficient algorithm that propagates the state probabilities through the image. Our algorithm, called Complete Enumeration Iteration (CEP), is flexible in the sense that it allows the use of different probability distributions as emission probabilities. Not only do we compare the performance of different probability functions plugged into our framework but also propose three methods to update the distributions of each state ?online? during the segmentation process. We compare our algorithm with a 2D-HMM standard algorithm and Iterated Conditional Modes (ICM) using real world images like a radiography or a satellite image as well as synthetic images. The experimental results are evaluated by the kappa coefficient (b). In those cases where the average kappa coefficient is higher than 0.7 we observe an average relative improvement of 8% of CEP with respect to the benchmark algorithms. For all other segmentation tasks CEP shows no significant improvement. Besides that, we demonstrate how the choice of the emission probability can have great influence on the segmentation results. Surprisingly, we observe that the normal distribution is an appropriate density function for many segmentation tasks.

Autores
Amicarelli, A.; Quintero Montoya, O.; di Sciascio, F.;

Resumen:
This work proposes a substrate feeding strategy for a bioprocess integrated with a biomass estimator based in nonlinear filtering techniques. The performance of the proposed estimator and the substrate strategy are illustrated for the δ-endotoxin production of Bacillus thuringiensis (Bt) in batch and fed batch cultures. Nonlinear filtering techniques constitutes an adequate option as estimation tool because of the strongly nonlinear dynamics of this bioprocess and also due to nature of the uncertainties and perturbations that cannot be supposed Gaussians distributed. Biomass estimation is performed from substrate and dissolved oxygen. Substrate feeding strategy is intended to obtain high product concentration. Simulations results along with their experimental verifications demonstrate the acceptable performance of the proposed biomass estimator and the substrate feeding strategy.

Autores
, S.; Amicarelli, A.; Ortiz, O.; Scaglia, G.; di Sciascio, F.;

Resumen:
Bacillus thuringiensis is a microorganism that allows the biosynthesis of δ-endotoxins with toxic properties against some insect larvae, being often used for the production of biological insecticides. A key issue for the bioprocess design consists in adequately tracking a pre-specified optimal profile of the dissolved oxygen concentration. To this effect, this paper aims at developing a novel control law based on a nonlinear dynamic inversion method. The closed-loop strategy includes an observer based on a Bayesian Regression with Gaussian Process, which is used for on-line estimation of the biomass present in the bioreactor. Unlike other approaches, the proposed controller leads to an improved response time with effective disturbance rejection properties, while simultaneously prevents undesired oscillations of the dissolved oxygen concentration. Simulation results based on available experimental data were used to show the effectiveness of the proposal.

Autores
Herrera, D.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:
In human-robot interaction, the incorporation of social rules results to be crucial to guarantee the comfort of the human. It must be obtained by means of improving the legibility of the robot motions, because developing soft and smooth motion does not guarantee entirely a social acceptable motion. Hence, in this paper a novel fuzzy logic approach is proposed to incorporate social rules in walking events, where the relative positions, orientations, distances and velocities between the robots and the humans are considered. Additionally to verify its performance, its incorporation in a path-following control through social forces is proposed. The simulation results demonstrate that the system is able to overcome many usual interferer situations, and to adapt its behavior to different interference events over time.

Autores
Herrera, D.; Tosetti, S.; Carelli, R.;

Resumen:
In the present article, it is presented the modeling and identification of an autonomous vehicle that has been designed for agricultural tasks. With the purpose of defining the best model structure, different models have been presented. Particularly, it is assumed that the lateral and longitudinal dynamics are decoupled dynamics, and based on this assumption these are modeled and identified in an isolated way. Particular emphasis was made in lateral and rotational dynamics. The vehicle under study is a quadricycle (ATV) that has been modified and adapted to work in an autonomous way. It has been presented simulation proofs and experimentation with the real vehicle that allows guaranteeing the performance of the developed models.

Autores
Herrera, D.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:
In human-robot interaction, the incorporation of social rules results to be crucial to guarantee the comfort of the human. It must be obtained by means of improving the legibility of the robot motions, because developing soft and smooth motion does not guarantee entirely a social acceptable motion. Hence, in this paper a novel fuzzy logic approach is proposed to incorporate social rules in walking events, where the relative positions, orientations, distances and velocities between the robots and the humans are considered. Additionally to verify its performance, its incorporation in a path-following control through social forces is proposed. The simulation results demonstrate that the system is able to overcome many usual interferer situations, and to adapt its behavior to different interference events over time.

Autores
Alzate, A.; Amicarelli, A.; Gomez, L.; di Sciascio, F.;

Resumen:
Set Theoretic Methods in Control using random sequences have been widely used previously as a tool for process design. In this paper, we present experimental results of determining control sets by using low-discrepancy deterministic sequences as an alternative to random sequences. We show that in certain situations this approach allows to reduce both significantly, the experimental error and the computational time.

Autores
Amicarelli, A.; Alzate, A.; di Sciascio, F.;

Resumen:
This paper extends and generalizes a model of Dissolved Oxygen (DO) dynamic developed for the delta-endotoxins of Bacillus thuringiensis (Bt) batch production process to a DO dynamical model that can be used for a broad class aerobic Endospore-forming Bacteria (AEFB). The most significant feature of this type of microorganism is the endospores generation in their life cycle. The generalization of the model allows to use the same parametric model structure for process control and state estimation purposes in a considerable variety of AEFB batch bioprocesses by selecting an appropriate set of parameters for each specific bioprocess.

Autores
Gandolfo, D.; Salinas, L.; Toibero, M.; Brandao, A.;

Resumen:
In the last decades, the research efforts related to Unmanned Aerial Vehicles (UAV) has grown substantially in terms of control stabilization and navigation strategies. However, the energy available on board is finite and this is a limiting factor that prevents engineers from coming up with the best aerial solution in many situations. In this paper the path following control of a helicopter UAV based on the kinematic model is proposed, using a feedback linearization technique. The helicopter speed is adjusted according to direction changes of the desired path. Thus, the aircraft should holds its own weight in the air for the shortest possible time, aiming to save energy without neglecting the position control errors which can accumulate when its velocity increases and path direction changes. The proposed controller output is coupled to a dynamic model of a helicopter in order to evaluate the dynamic effects and to adjust the controller parameters. The stability of the controller is demonstrated in the sense of Lyapunov theory and validated by simulation results.

Autores
Rossomando, F.; Soria, C.;

Resumen:

Autores
Rossomando, F.; Soria, C.;

Resumen:

Autores
Slawiñski, E.; Santiago, D.; Mut, V.;

Resumen:
This paper proposes a proportional derivative (PD)-like controller applied to the delayed bilateral teleoperation of wheeled robots with force feedback in face of asymmetric and varying-time delays. In contrast to bilateral teleoperation of manipulator robots, in these systems, there is a mismatch between the models of the master and slave (mobile robot), problem that is approached in this work, where the system stability is analysed. From this study, it is possible to infer the control parameters, depending on the time delay, necessary to assure stability. Finally, the performance of the delayed teleoperation system is evaluated through tests where a human operator drives a 3D simulator as well as a mobile robot for pushing objects.

Autores
, H.; Frizera Neto, A.; Freire Bastos, T.; Valadao, C.; Caldeira, E.; Carelli, R.;

Resumen:
Autism Spectrum Disorder is a set of developmental disorders that imply in poor social skills, lack of interest in activities and interaction with people. Treatments rely on teaching social skills and in such therapies robotics may offer aid. This work is a pilot study, which aims to show the development and usage of a ludic mobile robot for stimulating social skills in ASD children. Methods: A mobile robot with a special costume and a monitor to display multimedia contents was designed to interact with ASD children. A mediator controls the robot’s movements in a room prepared for interactive sessions. Sessions are recorded to assess the following social skills: eye gazing, touching the robot and imitating the mediator. The interaction is evaluated using the Goal Attainment Scale and Likert scale. Ten children were evaluated (50% with ASD), using as inclusion criteria children with age 7-8, without use of medication, and without tendency to aggression or stereotyped movements. Results: It was observed that the ASD group touched the robot about twice more in average than the control group (CG). They also looked away and imitated the mediator in a quite similar way as the CG, and showed extra social skills (verbal and non-verbal communication). These results are considered an advance in terms of improvement of social skills in ASD children. Conclusions: Our studies indicate that the robot stimulated social skills in 4/5 of the ASD children, which shows that its concepts are useful to improve socialization and quality of life.

Autores
Cifuentes, C.;extern341; Frizera Neto, A.; Freire Bastos, T.; Carelli, R.;

Resumen:
Human mobility is affected by different types of pathologies and also decreases gradually with age. In this context, Smart Walkers may offer important benefits for human assistedgait in rehabilitation and functional compensation scenarios. This paper proposes a new interaction strategy for human–walker cooperation. The presented strategy is based on the acquisition of human gait parameters by means of data fusion from inertial measurement units and a laser range finder. This paper includes the mathematical formulation of the controller, simulations, and practical experimentation of the interaction strategy, in order to show the performance of the control system, including the parameter detection methodology. In the experimental study, despite the continuous oscillation during the walking, the parameter estimation was suitable for assisted ambulation, showing an appropriate adaptive behavior with changes in human linear velocity. Finally, the controller keeps the walker continuously following in front of the human gait, and it is shown how the walker orientation follows the human orientation during the real experiments.

Autores
Baumgartner, J.; Flesia, A.; Gimenez, J.; Pucheta, J.;

Resumen:
Image segmentation is one of the fundamental problems in computer vision. In this work, we present a new segmentation algorithm that is based on the theory of two-dimensional hidden Markov models (2D-HMM). Unlike most 2D-HMM approaches we do not apply the Viterbi algorithm; instead we present a computationally efficient algorithm that propagates the state probabilities through the image. Our algorithm, called Complete Enumeration Iteration (CEP), is flexible in the sense that it allows the use of different probability distributions as emission probabilities. Not only do we compare the performance of different probability functions plugged into our framework but also propose three methods to update the distributions of each state ?online? during the segmentation process. We compare our algorithm with a 2D-HMM standard algorithm and Iterated Conditional Modes (ICM) using real world images like a radiography or a satellite image as well as synthetic images. The experimental results are evaluated by the kappa coefficient (b). In those cases where the average kappa coefficient is higher than 0.7 we observe an average relative improvement of 8% of CEP with respect to the benchmark algorithms. For all other segmentation tasks CEP shows no significant improvement. Besides that, we demonstrate how the choice of the emission probability can have great influence on the segmentation results. Surprisingly, we observe that the normal distribution is an appropriate density function for many segmentation tasks.

Autores
Alzate, A.; Amicarelli, A.; Gomez, L.; di Sciascio, F.;

Resumen:
En este trabajo se implementan los Métodos de Teoría de Conjuntos en Control como alternativa para el diseño y mejora de la controlabilidad de un proceso por lotes de cuatro estados. Para el cálculo de los conjuntos se proponen los Métodos de Quasi-MonteCarlo debido a la disminución del error y el tiempo de computo.

Autores
Orellana, A.;Alonso, T. ;Flores, C. ;

Resumen:

Autores
Herrera, D.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:

Autores
Toibero, M.; Roberti, F.; Herrera, D.; Amicarelli, A.; Carelli, R.;

Resumen:

Autores
Santi, S.; Accolti, E.; Grela, D. ; di Sciascio, F.;

Resumen:
Entropy has become important as a phenomenon of contemporaneity in art practice and theory. Since the composer Karlheinz Stockhausen stated the problem in his essay Structure and Experiential Time (1955), several authors focused their studies on the influence of the rate of auditory information in the perception of elapsed time. In this article the influence of physical duration and some aspects of entropy on perceived duration of a sound stimulus of about 35 s is studied. Dispersion of time interval between onset of events and the temporal density of events are aspects possibly related to the entropy. An experiment is conducted and preliminary results about the influence of entropy on the perception of duration are discussed.

Autores
Herrera, D.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:
Representations of human actions allow not only to infer the combining structure of complex movements, but also by creating a socially acceptable behavior. Take the case of a pedestrian following another one; he uses a mental kinematic control that allows to keep a relative distance and orientation between them. Additionally, his gait is also limited by its non holonomic and dynamic nature. Under the hypothesis that moving like humans will be acceptable for humans, this paper proposes a mechanism to indirectly identify human locomotion dynamics by using a kinematic leader-follower control as indirect inputs. The parameters of both of them are identified together by using human-human interaction data. Additionally, a control scheme based on feedback linearization is proposed to emulate the identified human dynamics. Finally, validation procedures over the measures of an experimental mobile robot are used to show the emulation of human locomotion dynamics. The results show that the robot is capable to emulate human locomotion dynamics, and, it could be useful to improve the social acceptance during human-robot interactions.

Autores
Herrera, D.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:
A complete characterization of the behavior in human-robot interactions (HRI) include both: the behavioral dynamic and the control laws that characterizes the way as the behavior is regulated with the perception data. In this way, when a pedestrian follows another one, it uses a mental kinematic control that allows to keep a relative distance and orientation between them, however it is also limited by its non holonomic and dynamic nature. Therefore, this paper proposes a mechanism to indirectly identify a first-order dynamic model of the human-locomotion by using a kinematic leader-follower control as a linkage of velocity references. Thus, experimental human-human interaction data is used to identify and validate the proposed model. This model is expected to be used to predict or to emulate human dynamic behavior by improving the social acceptance of robots.

Autores
Herrera, D.; Gimenez, J.; Toibero, M.; Carelli, R.;

Resumen:
Sharing the workspace or interacting directly with people in a social way is currently a key challenge in the design of mobile robot applications. An interesting field of study is related with the so-called hidden dimension, which relates the sense of security that a human feels when interacting with another one. Therefore, the researchers have been interested in developing human-friendly applications by abstracting social cues for the robotic design. One of these is the social zone, which acts like a repulsive potential field, and if it is not respected, an uncomfortable situation for humans is produced. In robotics, many approaches have been proposed to define and to avoid these fields, which contributes to improve the human comfort during interactions at least from a qualitative perspective. This paper proposes a novel nullspace-based (NSB) algorithm for a non-holonomic mobile robot platform, which is programmed to escort a human in a behavior-based paradigm. The emphasis is posed in the evasion of other humans in the environment by considering them as elliptical potential fields with non-holonomic motion. Finally, simulation results are presented to show the performance of the proposed control algorithm.

Autores
Toibero, M.; Roberti, F.; Herrera, D.; Amicarelli, A.; Carelli, R.;

Resumen:
This paper proposes a novel path following controller for Car-Like robots. This controller incorporates the saturation of the vehicle steering angle by considering of a Null-Space design. This way, the controller has a double objective: the primary task is to avoid the saturation of the steering angle by considering an appropriate Gaussian functional, and as a secondary task the robot asymptotically follows a specified path in the null space of the main task. This work includes the control system stability analysis according to Lyapunov theory, and reports simulation and experimental results for an outdoor Car-Like robot verifying the correct system behavior.

Autores
Miyara, F.;Pasch, V.; Accolti, E.;Miechi, P.;

Resumen:

Autores
Delmonte Zalazar, P.;Gareis, P.; Accolti, E.;

Resumen:

Autores
Herrera, D.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:

Autores
Herrera, D.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:

Autores
Sarapura, J.; Roberti, F.; Rosales, C.; Carelli, R.;

Resumen:

Autores
Escribá Rios Pablo ;Garcia Lucas ; Campillo Manrique, P.; Orosco, E.; Soria, C.;

Resumen:
El sistema desarrollado tiene la nalidad de controlar un prototipo de mano robótica real de impresión 3D libre y su versión virtual desde un computador o celular, mediante comunicación serie o vía Bluetooth. El modelo virtual del prototipo se realizó en V-REP cuya simulación se controla a través de una librería externa programada en C/C++. El sistema de cómputo principal se encarga de la recepción de datos serie, por cable o Bluetooth, su interpretación y generación de las acciones de control necesarias para el control de la mano. Este consta de un microcontrolador Tiva-C de Texas Instruments, un módulo Bluetooth y un módulo adaptador para tarjetas MicroSD. Los movimientos de la mano robótica real se realizan a través de seis servomotores, donde uno es el encargado de la rotación de la muñeca y los otros cinco de la apertura y cierre de los dedos. Además una aplicación por celular puede controlar la mano real por medio de Bluetooth sin necesidad de un servidor de escritorio.

Autores
Alzate, A.; Amicarelli, A.; Gomez, L.; di Sciascio, F.;

Resumen:
En este trabajo se propone usar secuencias determinísticas de baja discrepancia como método de obtención de cotas experimentales para el error de control de diferentes controladores avanzados diseñados para un proceso en particular. Además el método se presenta como una metodología de resintonía de los controladores que permite mejorar su desempeño. El trabajo encuentra aplicación en el área de bioprocesos en general y específicamente para el proceso por lotes de producción de delta-endotoxinas de Bacillus thuringiensis.