Publicaciones

Autores
Gimenez, J.; Roberti, F.; Toibero, M.; Carelli, R.;

Resumen:
This article addresses an unified solution to the trajectory tracking and path following problems for differential drive mobile robots (DDMR) considering a point of interest (PoI) with variable location relative to the vehicle. The mobile robot is modeled with an extended kinematic model avoiding typical singularities of this kind of vehicles, and allowing a straightforward definition of the corresponding inverse kinematics controller (IKC). This classical IKC fulfills the control objective with exponential error convergence but with the shortcoming of generating backward navigation when the PoI is located behind the DDMR, which is undesirable in some practical applications where the forward navigation must be preserved. This situation is theoretically analyzed, concluding that even though both forward and backward navigations correspond to equilibrium points of the closed loop, the stability of the forward navigation requires a PoI located in front of the DDMR, and the stability of the backward navigation requires a PoI located behind the DDMR. Finally, the article presents novel alternative controllers in order to always fulfill the motion objectives with stable forward navigation. Simulation results are presented to show the performance of the proposed controllers, and a real application of a robotic cane guiding its user is experimentally developed.

Autores
MORALES, H.; Aguirre Zapata, E.; di Sciascio, F.; Amicarelli, A.;

Resumen:
Este trabajo se enfoca en el proceso de Cristalización C en la industria azucarera. Su objetivo es mejorar el desempeño de un controlador clásico, con una ley de control Proporcional - Integral- Derivativa (PID) y un Controlador Predictivo Basado en Modelo No Lineal (NMPC) desarrollados previamente. Con este fin, se propone adicionar a dichas estrategias de control una referencia de sobresaturación variable, que se obtiene aplicando una función de corrección a un valor constante. La función de corrección depende de la curva de ebullición, que relaciona el nivel en el evaporador con la concentración deseada. Con estas mejoras se influye favorablemente en el proceso, garantizando que la sobresaturación opere en valores adecuados y que se alcance la concentración final con mayor eficiencia, en términos de ahorro de tiempo y consumo de energí­a en el proceso.

Autores
Gimenez, J.;Sebastian Sansoni ; Tosetti, S.; Capraro Fuentes, F.; Carelli, R.;

Resumen:
Agricultural environments with tree plantations usually present a regular structure that can be used by SLAM systems to improve self-location, and therefore, facilitate the autonomous navigation. In this context, tree trunks are natural landmarks that can be used to incorporate the environment structure into the problem modeling. This article presents a trunk detector solely based on RGB-D data obtained from a frontal-view stereo camera, and a SLAM system that incorporates the regular tree distribution of these crops. The trunk detector can be adapted to similar agricultural environments because its parameters have specific geometric meanings, which differentiates it from black box-type procedures. The structure-based SLAM system has theoretical and practical advantages over the well-known SLAM procedures in the mentioned context. This proposal can be executed on-line and is experimentally tested with databases obtained from a challenging agricultural environment. Results show a good performance and robustness when the database is spatially or temporally subsampled, even under adverse lighting conditions.