A Hierarchical Tracking Controller for Quadrotor Without Linear Velocity Measurements

This chapter deals with the position control of quadrotor unmanned aerial vehicle (UAV) when quadrotor’s linear velocity is unavailable. We propose a hierarchical tracking controller for quadrotor UAV. The proposed controller does not require measurements of linear velocity of quadrotor. A nonlinear filter that avoids the need for measurements of linear velocity has proposed such that a global stability result is obtained for the position tracking error. However, backstepping based on barrier Lyapunov function has been used for the attitude controller. The control design is achieved by means of the hierarchical control, that is, design the position controller and attitude controller separately. This allows us to choose different nonlinear techniques for each controller

Enhanced MPC for Omnidirectional Robot Motion Tracking Using Laguerre Functions and Non-Iterative Linearization

To cope with the computational complexity of the traditional model predictive control, and to reduce the error of the linearization and prediction processes, this paper presents an improved model predictive control algorithm, based on Laguerre functions, for the motion tracking of an omnidirectional mobile robot with non-iterative linearization. To design the controller, the kinematic modeling of the three-wheeled omnidirectional robot was first performed. Next, the model predictive algorithm was developed using Laguerre functions to parametrize the control signals. At each sampling instant of the online optimization, a linearization along the predicted trajectory, based on the duality principle between optimal control and stochastic filtering, was carried out to deal with the nonlinearities of the system. This non-iterative linearization provides better approximation of the nonlinear behavior which improves the prediction process and the tracking performance, with lower computational burden due to the use of the Laguerre functions. The new controller is applied to solve the trajectory-tracking problem of an omnidirectional robot. A comparative study between the proposed controller, the conventional model predictive control, and the nonlinear model predictive approach is made. Simulation results confirm that the new controller outperform the latter ones regarding tracking accuracy with considerably low computational effort. The feasibility of the controller is demonstrated by real-time experiment on the Robotino-Festo omnidirectional mobile robot

Suivi de trajectoires dans l'espace de travail d'une classe de manipulateurs flexibles

Classe de systèmes mécaniques -- Modèle dynamique -- Linéarisation par retour d'état -- Cacul des trajectoires désirées -- Loi de commande -- Simulation du contrôleur

Identification and characterization of dysregulated P-element induced wimpy testis-interacting RNAs in head and neck squamous cell carcinoma.

It is clear that alcohol consumption is a major risk factor in the pathogenesis of head and neck squamous cell carcinoma (HNSCC); however, the molecular mechanism underlying the pathogenesis of alcohol-associated HNSCC remains poorly understood. The aim of the present study was to identify and characterize P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) and PIWI proteins dysregulated in alcohol-associated HNSCC to elucidate their function in the development of this cancer. Using next generation RNA-sequencing (RNA-seq) data obtained from 40 HNSCC patients, the piRNA and PIWI protein expression of HNSCC samples was compared between alcohol drinkers and non-drinkers. A separate piRNA expression RNA-seq analysis of 18 non-smoker HNSCC patients was also conducted. To verify piRNA expression, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed on the most differentially expressed alcohol-associated piRNAs in ethanol and acetaldehyde-treated normal oral keratinocytes. The correlation between piRNA expression and patient survival was analyzed using Kaplan-Meier estimators and multivariate Cox proportional hazard models. A comparison between alcohol drinking and non-drinking HNSCC patients demonstrated that a panel of 3,223 piRNA transcripts were consistently detected and differentially expressed. RNA-seq analysis and in vitro RT-qPCR verification revealed that 4 of these piRNAs, piR-35373, piR-266308, piR-58510 and piR-38034, were significantly dysregulated between drinking and non-drinking cohorts. Of these four piRNAs, low expression of piR-58510 and piR-35373 significantly correlated with improved patient survival. Furthermore, human PIWI-like protein 4 was consistently upregulated in ethanol and acetaldehyde-treated normal oral keratinocytes. These results demonstrate that alcohol consumption may cause dysregulation of piRNA expression in HNSCC and in vitro verifications identified 4 piRNAs that may be involved in the pathogenesis of alcohol-associated HNSCC

EPRL Sliding Mode Flight Controller with Model-based Switching Manifold of a Quad-Rotor UAV

Presentación realizada en el marco Proyecto PINV18-765: Vehículos aéreos no tripulados en aplicaciones para la agricultura de precisión para el monitoreo de cultivos agrícolas. Cuyo objetivo general fue: el Estudio, investigación, análisis y validación experimental de, por un lado, avanzadas estrategias de control de vuelo de vehículos no tripulados (UAV) y, por otro, de algoritmos de procesamiento de imágenes obtenidas por el UAV, orientada al análisis de cultivos agrícolas enfocado al desarrollo del sector agropecuario.CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI

Attitude tracking of a tri-rotor uav based on robust sliding mode with time delay estimation

The paper presents a robust sliding mode with time delay estimation method for controlling the attitude of a tri-rotor unmanned aerial vehicle (UAV) in presence of uncertainties and disturbances. The proposed control algorithm allows high accuracy tracking since a good disturbance estimation is provided using time delay estimation method and allows chattering reduction. The stability analysis of the closedloop system is presented using the theory of Lyapunov. Finally, two numerical simulations are presented in the presence of disturbances to show the effectiveness of the proposed nonlinear control scheme.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Speed control of a five-phase induction motor drive using modified super-twisting algorithm

The present work proposes an alternative for the inner current control based on the modified super-twisting algorithm with time delay estimation. Simulation results were carried out to verify the performance of the proposed robust control strategy for a five-phase induction motor drive. A stability analysis is also presented.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Alcohol-dysregulated miR-30a and miR-934 in head and neck squamous cell carcinoma.

BackgroundAlcohol consumption is a well-established risk factor for head and neck squamous cell carcinoma (HNSCC); however, the molecular mechanisms by which alcohol promotes HNSCC pathogenesis and progression remain poorly understood. Our study sought to identify microRNAs that are dysregulated in alcohol-associated HNSCC and investigate their contribution to the malignant phenotype.MethodUsing RNA-sequencing data from 136 HNSCC patients, we compared the expression levels of 1,046 microRNAs between drinking and non-drinking cohorts. Dysregulated microRNAs were verified by qRT-PCR in normal oral keratinocytes treated with biologically relevant doses of ethanol and acetaldehyde. The most promising microRNA candidates were investigated for their effects on cellular proliferation and invasion, sensitivity to cisplatin, and expression of cancer stem cell genes. Finally, putative target genes were identified and evaluated in vitro to further establish roles for these miRNAs in alcohol-associated HNSCC.ResultsFrom RNA-sequencing analysis we identified 8 miRNAs to be significantly upregulated in alcohol-associated HNSCCs. qRT-PCR experiments determined that among these candidates, miR-30a and miR-934 were the most highly upregulated in vitro by alcohol and acetaldehyde. Overexpression of miR-30a and miR-934 in normal and HNSCC cell lines produced up to a 2-fold increase in cellular proliferation, as well as induction of the anti-apoptotic gene BCL-2. Upon inhibition of these miRNAs, HNSCC cell lines exhibited increased sensitivity to cisplatin and reduced matrigel invasion. miRNA knockdown also indicated direct targeting of several tumor suppressor genes by miR-30a and miR-934.ConclusionsAlcohol induces the dysregulation of miR-30a and miR-934, which may play crucial roles in HNSCC pathogenesis and progression. Future investigation of the alcohol-mediated pathways effecting these transformations will prove valuable for furthering the understanding and treatment of alcohol-associated HNSCC

Robust finite-time position and attitude tracking of a quadrotor UAV using super-twisting control algorithm with linear correction terms

This work investigates the problem of finite-time position and attitude trajectory of quadrotor unmanned aerial vehicle systems based on a modified second order sliding mode algorithm. The selected algorithm is a modified super-twisting with both nonlinear and linear correction terms.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Cascade first and second order sliding mode controller of a quadrotor UAV based on exponential reaching law and modified super-twisting algorithm

Unmanned aerial vehicles have become a disruptive technology, which has experienced exponential growth in several applications. The control of these vehicles is a fairly wide area and the cascade PID controller is the most used in practice. However, this latter structure doesn’t ensure high performances in the presence of unmodelled dynamics, uncertainties and external abrupt disturbances. To that end, this work proposes a new method that consists of a non-linear cascade configuration of the variable structure control between first order sliding mode based on exponential reaching law and modified super-twisting second order sliding mode algorithm. The developed method is tested on simulation on a quadrotor system, the results obtained demonstrate good performance for trajectory tracking and as well as other non-linear controller options, it is robust against unmodeled dynamics and disturbances.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI