DIM - MECATRAN - Artículos de revistas

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Simultaneous Estimation of Vehicle Sideslip and Roll Angles Using an Event-Triggered-Based IoT Architecture
(MDPI, 2024-01-11) Viadero Monasterio, Fernando; García Guzmán, Javier; Melendez Useros, Miguel; Jimenez Salas, Manuel; López Boada, Beatriz; López Boada, María Jesús; Ministerio de Economía y Competitividad (España)
In recent years, there has been a significant integration of advanced technology into the automotive industry, aimed primarily at enhancing safety and ride comfort. While a notable proportion of these driver-assist systems focuses on skid prevention, insufficient attention has been paid to addressing other crucial scenarios, such as rollovers. The accurate estimation of slip and roll angles plays a vital role in ensuring vehicle control and safety, making these parameters essential, especially with the rise of modern technologies that incorporate networked communication and distributed computing. Furthermore, there exists a lag in the transmission of information between the various vehicle systems, including sensors, actuators, and controllers. This paper outlines the design of an IoT architecture that accurately estimates the sideslip angle and roll angle of a vehicle, while addressing network transmission delays with a networked control system and an event-triggered communication scheme. Experimental results are presented to validate the performance of the IoT architecture proposed. The event-triggered scheme of the IoT solution is used to decrease data transmission and prevent network overload.
Event-Triggered Robust Path Tracking Control Considering Roll Stability Under Network-Induced Delays for Autonomous Vehicles
(IEEE, 2023-10-13) Viadero Monasterio, Fernando; Nguyen, Anh-Tu; Lauber, Jimmy; López Boada, María Jesús; López Boada, Beatriz
This paper proposes a multi-input multi-output (MIMO) method for path tracking control of autonomous vehicles under network-induced delays while taking into account the roll dynamics to improve both the driving safety and the passenger comfort. The steering control is directly applied to the front wheels, while the anti-roll moment is exerted by an active suspension. The asynchronous phenomenon caused by the sampling process and the time-varying vehicle speed are explicitly taken into account in the control design using a polytopic linear parameter-varying (LPV) control approach. Moreover, to avoid using costly vehicle sensors and complex control structures, a static output feedback (SOF) control scheme is considered. An effective event-triggering mechanism is also proposed to alleviate the communication burden of the vehicle networked control system. Based on augmented Lyapunov-Krasovskii functional, the control design conditions are derived to guarantee the vehicle closed-loop stability under the effects of transmission delays, event-triggered control signals and time-varying parameters. The design procedure is reformulated as an iterative optimization problem involving linear matrix inequality (LMI) constraints, which can be effectively solved with available numerical solvers. The proposed event-triggered SOF controller is evaluated with the vehicle dynamics simulation software CarSim under several dynamic scenarios. A comparative study with related vehicle control results is performance to emphasize the effectiveness of the control method in terms of path tracking performance, driving safety and comfort, and data communication efficiency of the vehicle networked control system.
Integral-based event triggering actuator fault-tolerant control for an active suspension system under a networked communication scheme
(IEEE, 2023-11-01) Viadero Monasterio, Fernando; López Boada, Beatriz; Zhang, Hui; López Boada, María Jesús; Ministerio de Ciencia e Innovación (España)
This paper presents a research on the problem of enhancing ride safety and comfort during driving of a vehicle using an active suspension control system under a networked communication. An integral event-triggered condition is defined to reduce the network usage over time, a Dynamic Output Feedback Controller is designed under the H¿ criteria and Lyapunov-Krasovskii functionals to guarantee the system stability, actuator faults are considered for the controller design. The control algorithm is solved in terms of Linear Matrix Inequalities. In order to prove a practical feasibility, control performance characteristics for vibration suppression are evaluated under various road conditions.
Novel Bayesian Inference-Based Approach for the Uncertainty Characterization of Zhang's Camera Calibration Method
(MDPI, 2023-09-15) Gutiérrez Moizant, Ramón Alberto; López Boada, María Jesús; Ramírez Berasategui, María Beatriz; Al Kaff, Abdulla Hussein Abdulrahman; Ministerio de Ciencia e Innovación (España)
Camera calibration is necessary for many machine vision applications. The calibration methods are based on linear or non-linear optimization techniques that aim to find the best estimate of the camera parameters. One of the most commonly used methods in computer vision for the calibration of intrinsic camera parameters and lens distortion (interior orientation) is Zhang¿s method. Additionally, the uncertainty of the camera parameters is normally estimated by assuming that their variability can be explained by the images of the different poses of a checkerboard. However, the degree of reliability for both the best parameter values and their associated uncertainties has not yet been verified. Inaccurate estimates of intrinsic and extrinsic parameters during camera calibration may introduce additional biases in post-processing. This is why we propose a novel Bayesian inference-based approach that has allowed us to evaluate the degree of certainty of Zhang¿s camera calibration procedure. For this purpose, the a prioriprobability was assumed to be the one estimated by Zhang, and the intrinsic parameters were recalibrated by Bayesian inversion. The uncertainty of the intrinsic parameters was found to differ from the ones estimated with Zhang¿s method. However, the major source of inaccuracy is caused by the procedure for calculating the extrinsic parameters. The procedure used in the novel Bayesian inference-based approach significantly improves the reliability of the predictions of the image points, as it optimizes the extrinsic parameters.
Diseño de un estimador basado en redes neuronales artificiales para caracterizar la frenada de un vehículo
(Fundación Técnica Industrial, 2021-11) Garrosa Solana, María; Olmeda Santamaría, Ester; Sanz Sánchez, Susana; Díaz López, Vicente
Hoy en día, los vehículos inteligentes están equipados con interfaces de usuario muy avanzadas que pueden reaccionar ante las decisiones y necesidades del conductor. De esta manera mejora la dinámica vehicular según la situación de conducción evitando posibles colisiones fortuitas. Esta tecnología permite tomar decisiones sobre la conducción con un nivel de resolución superior al humano a la hora de, por ejemplo, realizar una frenada de emergencia ante un imprevisto. Con este trabajo se pretende que, en un futuro, se pueda gobernar el sistema de frenado de manera automática y que el vehículo pueda reproducir los hábitos y las formas de actuación de los conductores durante la maniobra de frenada de un vehículo, pero corrigiendo los posibles fallos humanos ligados a distracciones, falta de visibilidad o tiempos de reacción. Un sistema de frenado inteligente ha de ser capaz de obtener información de los diferentes sensores embarcados en el vehículo, procesar los datos obtenidos a través de los mismos y transformarlos en información útil para el control activo del automóvil. Con el vehículo instrumentado con los sensores capaces de proporcionar en tiempo real información sobre el sistema de frenado se llevan a cabo una serie de ensayos. Los datos obtenidos experimentalmente durante la realización de los ensayos se utilizan para el diseño de un estimador mediante la técnica de redes neuronales artificiales. Se estimarán las variables medidas por los sensores con el fin de caracterizar una frenada.
Experimental verification of the boundary conditions in the success of the Brazilian test with loading arcs. An uncertainty approach using concrete disks
(Elsevier, 2020-08) Gutiérrez Moizant, Ramón Alberto; Ramírez Berasategui, María Beatriz; Sánchez-Sanz, S.; Santos Cuadros, Silvia
The present work analyses the reliability of the Brazilian test with loading arcs. A new testing set up has allowed to determine in an effective way the real load of the failure initiation as this moment was not always or correctly detected by the universal testing machine. The instrumentation used is a simple and low-cost method that allows to know the possible pressure distribution in the contact zone as well as the final contact angle. It has been observed that the success of the test depends mainly on the surface finish of the parts involved, their geometric tolerances and the symmetry of the applied load. These boundary conditions have a direct effect in the contact pressure distribution. The possible failure modes observed experimentally have been simulated with the finite element methods. For this, the contact boundary condition has been changed and the possible stress distribution in term of Griffith equivalent stress has been obtained. The numerical analysis allows to study the influence of the initial contact condition on the success of the test and agrees with the experimental results. Furthermore, an uncertainty analysis in the expression of the tensile strength confirms that, when the test is valid, a crack appears suddenly in the central area of the disk, as observed experimentally, so there is no need to determine if the starting point is in the centre. Additionally, it has been observed that the initial crack length depends on the type of pressure distribution in the contact zone. Finally, a series of recommendations are given in order to minimize both the variability of the final contact angle and the risk of premature failure of the Brazilian disk.
Feasibility evaluation and critical factor analysis for subway scheduling
(Wit Press, 2017) Zhu, Taomei; Mera, J.M.; Castellote, E.; Lopez, J.
In strategic subway scheduling stage, the conflict sometimes comes from different requirements of the subway operator. This study aims to investigate the significant factors concerning strategic subway scheduling problem and to develop an automatic procedure of feasibility analysis in subway scheduling. To this end, accurate simulation of train movement (via a simulator, named HAMLET) is applied first by considering the line geography, train performances, actual speed restrictions, etc. The critical elements of subway scheduling and their correlations are then studied and a bound structure of the critical factors is established. The feasibility of primary plan requirements is analysed with the restrictions of the bound structure. Infeasible aspects and possible adjustments are shortly discussed. Finally, the subsequent applications including schedule generation and optimization according to various objectives are indicated as well.
Lateral dynamic simulation of a bus under variable conditions of camber and curvature radius
(MDPI, 2022-09-01) Olmeda Santamaría, Ester; Carrillo Li, Enrique Roberto; Rodríguez Hernández, Jorge; Díaz López, Vicente
The objective of this paper is to describe a model for the simulation of the lateral dynamics of a vehicle, specifically buses, under variable trajectory conditions, such as camber and radius of curvature; in addition, a variable speed is added as a simulation parameter. The objective of this study is the prevention of vehicle rollover and sideslip. An 8 degrees of freedom model was developed, considering a front and a rear section of the bus with its respective suspension system, and both sections have been connected by a torsion spring that emulates the torsional stiffness of the vehicle chassis. A Panhard bar is also added at the rear as an additional element to the suspension and the behavior of the bus when it is added is analyzed. This model also allows the evaluation of the force on each suspension component, which allows for future controllability of the active suspension components. The results show the dynamic behavior of the vehicle, and some indicators are introduced to show the possible sideslip or rollover. As a conclusion, the influence of the road parameters on the dynamic behavior of the bus and the effect of the Panhard bar on the dynamic behavior of the bus can be pointed out.
The general dispersion relation for the vibration modes of helical springs
(MDPI, 2022-08-01) Prieto Fernández, Leopoldo; Quesada González, Alejandro; Gómez Amador, Ana María; Díaz López, Vicente
A system of mathematical equations was developed for the calculation of the natural frequencies of helical springs, its predictions being compared with finite element simulation with ANSYS®. Authors derive the general equations governing the helical spring vibration relative to the Frenet trihedral representing the normal, binormal and tangent unit vectors to the spring medium line. The dispersion relation ω = f (k) has been obtained to model a wave traveling along the axis of the wire.
New methodology for estimating the shear strength of layering in slate by using the Brazilian test
(Springer, 2019-06-01) García-Fernández, C. C.; González-Nicieza, C.; Álvarez-Fernández, M. I.; Gutiérrez Moizant, Ramón Alberto
A new method is proposed in order to estimate the shear strength of schistosity planes in slate in terms of Mohr-Coulomb cohesion and internal friction angle. The procedure consists in carrying out the Brazilian method under different loading-foliation angles, for which experimental tests were achieved in slates from the northwest of the Iberian Peninsula (Spain). The experimental fracture patterns were analytically studied and justified by simulating the stress field in the discontinuity planes contained in the whole sample, taking into account the first failure registered in the tests. By combining experimental and analytical studies and a procedure based on the representation of the threshold state of stressesin the elastic regimein the failure plane, it is possible to estimate the foliation's strength envelope through a lineal adjustment according to the Mohr-Coulomb criterion and, thus, to characterize the layering. Finally, the proposed procedure was validated by the direct shear test. The cohesion and the internal friction angle obtained with this convenctional test were very close to that calculated by the proposed method, verifying the methodology developed by the authors. This procedure may be interesting in various engineering applications, either in the study of the properties of cleavage in slate, which is commonly used as an industrial rock, or in dam foundations, underground excavations and slope engineering, since one of the main failures in civil engineering is due to sliding along weak planes.
Estimation of tire-road contact forces through a model-based approach employing strain measurements
(Springer, 2022-08) García-Pozuelo Ramos, Daniel; Olatunbosun, Oluremi; Palli, Gianluca; Strano, Salvatore; Terzo, Mario; Tordela, Ciro
The employment of intelligent tires to test the vehicle performances is ever-increasing in the last years. Many research activities have been made to correlate measurements provided by sensors to the tire dynamics. In this paper, a novel tire-road forces estimation technique is presented. The developed estimator is based on an approximation of the well-known Flexible Ring Tire Model (FRTM) and therefore, it is suitable for real-time normal and tangential forces identification. Only the tread band strain measurements are employed in the developed algorithm which can estimate the tire-road forces at every wheel revolution. The tool is validated through both numerical and experimental tests. The results indicate that the developed estimation algorithm, obtained by a mathematical inversion of the FRTM, can be employed as a monitoring tool for tires and vehicles.
Tire slip H∞ control for optimal braking depending on road condition
(MDPI, 2023-02-01) Melendez Useros, Miguel; Jimenez Salas, Manuel; Viadero Monasterio, Fernando; López Boada, Beatriz; Ministerio de Ciencia e Innovación (España)
Tire slip control is one of the most critical topics in vehicle dynamics control, being the basis of systems such the Anti-lock Braking System (ABS), Traction Control System (TCS) or Electronic Stability Program (ESP). The highly nonlinear behavior of tire–road contact makes it challenging to design robust controllers able to find a dynamic stable solution in different working conditions. Furthermore, road conditions greatly affect the braking performance of vehicles, being lower on slippery roads than on roads with a high tire friction coefficient. For this reason, by knowing the value of this coefficient, it is possible to change the slip ratio tracking reference of the tires in order to obtain the optimal braking performance. In this paper, an H∞ controller is proposed to deal with the tire slip control problem and maximize the braking forces depending on the road condition. Simulations are carried out in the vehicular dynamics simulator software CarSim. The proposed controller is able to make the tire slip follow a given reference based on the friction coefficient for the different tested road conditions, resulting in a small reference error and good transient response.
Material characterization for FEM simulation of sheet metal stamping processes
(SAGE, 2014) Quesada González, Alejandro; Gauchia Babe, Antonio; Álvarez Caldas, Carolina; San Román García, José Luis
Sheet metal forming is an important technology in manufacturing, especially in the automotive industry. Today, engineering simulation tools based on the finite elements method are employed regularly in the design of stamping dies for sheet metal parts. However, a bad material model choice or the use of nonaccurate enough parameters can lead to imprecise simulation results. This work uses ANSYS LS-DYNA software to analyze several material models and the influence of their parameter values in FEM simulation results. The main tool to solve these problems is an application designed to assist die stamp designers. The program allows a procedure to be defined to obtain the values of the properties of an unknown material, which combines finite element simulations with real experimental results. Results obtained for the simulation of a real automotive part are analyzed and compared with the real experimental results. Parameters involved in each material model have been identified, and their influence in final results has been quantified. This is very useful to fit material properties in other simulations. This paper fulfils an identified need in the manufacturing industry. In fact, the proposed application is currently being used by a manufacturer of automotive components.
Methodology for bus structure torsion stiffness and natural vibration frequency prediction based on a dimensional analysis approach
(Springer, 2014-04-01) Gauchía Babé, Antonio; Olmeda Santamaría, Ester; López Boada, María Jesús; López Boada, Beatriz; Díaz López, Vicente; Comunidad de Madrid
Engineering bus design requires testing of bus structures prototypes in order to guarantee a certain level of strength and an appropriate static and dynamic behavior of the bus superstructure when exposed to road loads. However, experimental testing of real bus structures is very expensive as it requires expensive resources and space. If testing is done on a scale bus model the previous required expenses are considerably reduced. Therefore, a novel methodology based on dimensional analysis applied to bus structure prediction to evaluate the bus structure static and dynamic performance is proposed. The static performance is evaluated attending to torsion stiffness and the dynamic in terms of the natural vibration frequencies and rollover threshold. A scale bus has been manufactured and dimensionless parameters have been defined in order to project the results obtained in the scale bus model to a larger model. Validation of the proposed methodology has been carried out under experimental and finite element analysis.
Determining the stress distribution in a bicycle crank under in-service loads
(Springer, 2016-04-01) Calvo Ramos, José Antonio; Álvarez Caldas, Carolina; Quesada González, Alejandro; San Román García, José Luis
New techniques have been introduced in the design process of most of the components of a bicycle. One of the main purposes of this introduction is trying to achieve the best weight/rigidity relation. However, all these advances have to take into account the security of the rider. Unexpected failures of some components such as stem, handlebar, or cranks, can cause serious injuries to cyclists and have to be prevented. Standard EN 14781:2006 establishes the safety and performance requirements that every bicycle and every component must fit from the point of view of fatigue failure. In this work, several bicycles cranks will be experimentally tested under the loading conditions of the reference standard. The stresses on the critical points will be analyzed to determine the influence of any variation in the test conditions. According to obtained data, several changes in the conditions of the standard will be proposed. Also, loading tolerance values for the test will be suggested, because they are not established in the standard.
Simultaneous Estimation of Vehicle Sideslip and Roll Angles Using an Integral-Based Event-Triggered Hinfinity Observer Considering Intravehicle Communications
(IEEE, 2023-04) López Boada, Beatriz; Viadero Monasterio, Fernando; Zhang, Hui; López Boada, María Jesús; Ministerio de Economía y Competitividad (España)
In recent years, several technological advances have been incorporated into vehicles to ensure their safety and ride comfort. Most of these driver-assistance technologies aim to prevent skidding, whereas less attention has been paid to the avoidance of other dangerous situations such as a rollover. Since knowledge of slip and roll angles is critical to the control and safety of vehicle handling, their estimation remains of great interest when addressing emerging constraints in modern technologies involving networked communications and distributed computing. This paper presents an integral-based event-triggered H ¿ observer to simultaneously estimate the sideslip and roll angles, considering intravehicle communications with a networked-induced delay. As the longitudinal velocity and tire cornering stiffness of a vehicle can vary significantly during driving and have a strong influence on vehicle lateral stability, these time-varying parameter uncertainties are considered in the design of the observer. The simulation and experimental results demonstrate the effectiveness of the proposed observer.
Educational Resources for Self-learning of Descriptive Geometry
(Springer, 2019-01-01) Álvarez Caldas, Carolina; García Prada, Juan Carlos; Meneses Alonso, Jesús; Santos Cuadros, Silvia; Gómez Amador, Ana María; Díaz Álvarez, Antonio; Calvo Ramos, José Antonio; Muñoz Sánchez, Ana
In this work, two educational resources for self-learning of Descriptive Geometry are presented: the “Zero Course” and the “Support Course”. The creation of this e-learning material responds to the need that our students at University Carlos III de Madrid have to reach a minimum level at the beginning (Zero Course), and during (Support Course) the first course on technical drawing. First, the need is made out through results of surveys carried out in previous years. Then, some e-learning applications are exposed, among which the most appropriate to the need are chosen. Finally, the designed courses are described including all the technical resources. The results of the surveys carried out on the students of these courses, as well as some statistics of their qualifications, are also presented.
Characterization of the loss of grip condition in the Strain-Based Intelligent Tire at severe maneuver
(Elsevier, 2022-04-01) Mendoza Petit, María Fernanda; García-Pozuelo Ramos, Daniel; Díaz López, Vicente; Garrosa Solana, María
The early detection of the instantaneous tire–road condition enables the control systems to react against the risk of the vehicle's loss of control. This situation usually occurs when the phenomena of stick–slip is not present in the tire–road interaction yielding the full slip of the tire (the whole contact patch is gliding). The relation between the friction force and the vertical load of the tire can be used as an indicator of this loss of grip when it is higher than the maximum capacity of friction used for the surfaces in contact. Nonetheless, this limit of friction is currently unknown. This study proposes the development of the tire as an active sensor able to provide all this information. Previous studies have shown that the Strain-based Intelligent Tire enables the monitoring of the forces in the tire–road interaction, the wheel load, the effective radius, the contact length, and the wheel velocity in the contact patch. These parameters affect the tire–road friction characterization. Therefore, it is proposed the integration of the LuGre model with the achievements of the Strain-Based Intelligent Tire in order to estimate the adherence limit. To show the effectiveness of the methodology proposed it is used the CarSim™ simulation software. The validation process is carried out monitoring the limit of adherence with a set of vehicle’s severe maneuvers, where the dynamic behavior of the vehicle highlights its influence in the operational condition of the tire in order to expose the wheels to full slip.
Computational verification of the optimum boundary condition of the Brazilian tensile test
(Springer-Verlag GmbH Austria, part of Springer Nature, 2018-11) Gutiérrez Moizant, Ramón Alberto; Ramírez Berasategui, María Beatriz; Santos Cuadros, Silvia; García Fernández, C.
The present research analyses the configuration of jaws to avoid the premature failure of the disc in the Brazilian test. The objective is to depict the loading device configuration that most likely produces results comparable to the Hondros' analytical stress solution. To this end, several numerical analyses have been carried out for different contact angles with the finite element method. It was deduced that the final contact angle plays an important part in the success of the Brazilian test and that the Griffith criterion can be fulfilled if the equivalent stress is calculated. Additionally, the orientation of the forces in the contact between the loading device and the disc has been studied for different friction conditions. According to the numerical results, it was found that a loading arc configuration of 20 degrees shows the best agreement with the probable values given by the analytical stress model when the uncertainty of its magnitudes is taken into account. The study also demonstrates that the friction in the contact between the optimal loading configuration and the disc does not seem to significantly affect the theoretical predictions in the centre of the disc.
Bending collapse analysis for thin and medium-thin-walled square and rectangular hollow shapes
(2021-08-01) López Boada, María Jesús; Rodríguez Hernández, Jorge A.; Lavayen Farfán, Daniel; Comunidad de Madrid
Thin-walled hollow shapes are of great interest in many industries with weight constraints due to their availability, low price, and strength to weight ratio. However, they are also prone to localized bending collapse, which can be used as an energy absorption mechanism during deformation. Up until now, industrial applications have relied on numerical simulations, non-standardized tests, and a handful of theories to address the bending collapse behavior. In this paper, a modification to the most widely used theory is presented and adapted for hollow shapes with greater thickness that cannot be considered. To verify the accuracy of the proposed modification, a comparison with a detailed FEM model, validated through various three-point bending collapse experimental tests, has been performed. The results seem to show that the proposed modifications can predict the maximum load and collapse stage behavior of hollow shapes with more accuracy than the original analytical model. Thus, the proposed modification may be used to predict the collapse behavior of commercially available square and rectangular hollow shapes in different fields of application.

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