A novel frequency dependent model based on trigonometric functions for a magnetorheological damper

In this paper, a novel frequency dependent MR damper model based on trigonometric functions is proposed. The model presents the following advantages in comparison with other previously proposed models: (1) it is based on algebraic functions instead of differential equations, so that it does not present convergence problems when noisy inputs from experimental measurements are used; (2) the number of parameters is reasonable, so that it makes the model computationally efficient in the context of parameter identification and (3) the model has to take into account the variation of the parameters as a function, not only of the applied current but also of the frequency of excitation. Experimental results confirm that the proposed frequency dependent MR damper model improves the accuracy of the model in force simulation.Funds provided by the Spanish Government through the CICYT Projects TRA2008-05373/AUT and TRA2011-28548-C02-0

A Novel Inverse Dynamic Model for a Magnetorheological Damper based on Network Inversion

Semi-active suspensions based on magnetorheological (MR) dampers are receiving significant attention specially for control of vibration isolation systems. The nonlinear hysteretic behaviour of MR dampers can cause serious problems in controlled systems such as instability and loss of robustness. Most of the developed controllers determine the desired damping forces which should be produced by the MR damper. Nevertheless, the MR damper behaviour can only be controlled in terms of the applied current (or voltage). In addition to this, it is necessary to develop an adequate inverse dynamic model in order to calculate the command current (or voltage) for the MR damper to generate the desired forces as close as possible to the optimal ones. Due to MR dampers are highly nonlinear devices, the inverse dynamics model is difficult to obtain. In this paper, a novel inverse MR damper model based on a network inversion to estimate the necessary current (or voltage) such as the desired force is exerted by the MR damper is presented. The proposed inverse model is validated carrying out experimental tests. In addition, a comparison of simulated tests with other damper controllers is also presented. Results show the effectiveness of the network inversion for inverse modeling of an MR damper, so that the proposed inverse model can act as a damper controller to generate the command current (or voltage) to track the desired damping force.This work was supported by the funds provided by the Spanish Government through the CICYT projects TRA2008-05373/AUT and TRA2011-28548-C02-01.Publicad

Study of van roadworthiness considering their maintenance and periodic inspection. The Spanish case

In Europe, traffic road safety has clearly improved due to many factors. One of them is the improvement of the roadworthiness. However, accidents of vans and light goods vehicles (LGV) have not followed the decreasing tendency of other vehicles. Several studies suggest that vehicle defects are relevant to the cause of accidents. It would be ideal if vehicle owners continuously kept their vehicles in compliance with the roadworthiness standards. Another important aspect to operate with roadworthy vans is the maintenance programs. It is probable that many van owners do not adequately maintain their vehicles or the maintenance programs are not sufficient with the periodic motor vehicle inspections (PMVI) intervals or with the items inspected. This paper analyses the maintenance schedules and PMVI of vans in order to assess the influence of these parameters in their higher accident rate. The conclusions provided can enable public administrations to modify enforcement laws, regarding time control of driving and PMVI.Proyecto financiado por el Ministerio de Fomento en el marco del Plan I+D+i 2008/2011: Desarrollo y aplicación de una metodología integrada para el estudio de los accidentes de tráfico con implicación de furgonetas (P24/08)”. FURGOSEG

A robust observer based on energy-to-peak filtering in combination withneural networks for parameter varying systems and its application to vehicleroll angle estimation

This paper presents a robust observer based on energy-to-peak filtering in combination with a neural network for vehicle roll angle estimation. Energy-to-peak filtering estimates the minimised error for any bounded energydisturbance. The neural network acts as a 'pseudo-sensor' to estimate a vehicle 'pseudo-roll angle', which is used as the input for the energy-to-peak-based observer. The advantages of the proposed observer are as follows. 1) Itdoes not require GPS information to be utilised in various environments. 2) It uses information obtained from sensors that are installed in current vehicles, such as accelerometers and rate sensors. 3) It reduces computationtime by avoiding the calculation of observer gain at each time sample and utilising a simplified vehicle model. 4) It considers the uncertainties in parameters of the vehicle model. 5) It reduces the effect of disturbances. Bothsimulation and experimental results demonstrate the effectiveness of the proposed observer.This work is supported by the Spanish Government through the Project TRA2013-48030-C2-1-R, which is gratefully acknowledged

Vehicle sideslip angle measurement based on sensor data fusion using an integrated ANFIS and an Unscented Kalman Filter algorithm

Most existing ESC (Electronic Stability Control) systems rely on the measurement of both yaw rate and sideslip angle. However, one of the main issues is that the sideslip angle cannot be measured directly because the sensors are too expensive. For this reason, sideslip angle estimation has been widely discussed in the relevant literature. The modeling of sideslip angle is complex due to the non-linear dynamics of the vehicle. In this paper, we propose a novel observer based on ANFIS, combined with Kalman Filters in order to estimate the sideslip angle, which in turn is used to control the vehicle dynamics and improve its behavior. For this reason, low-cost sensor measurements which are integrated into the actual vehicle and executed in real time have to be used. The ANFIS system estimates a "pseudo-sideslip angle" through parameters which are easily measured, using sensors equipped in actual vehicles (inertial sensors and steering wheel sensors); this value is introduced in UKF in order to filter noise and to minimize the variance of the estimation mean square error. The estimator has been validated by comparing the observed proposal with the values provided by the CARSIM model, which is a piece of experimentally validated software. The advantage of this estimation is the modeling of the non-linear dynamics of the vehicle, by means of signals which are directly measured from vehicle sensors. The results show the effectiveness of the proposed ANFIS+UKF-based sideslip angle estimator

Sensor fusion based on a Dual Kalman Filter for estimation of road irregularities and vehicle mass under static and dynamic conditions

Mass is an important parameter in vehicle dynamics because it affects not only safety but also comfort. The mass influences the three movements corresponding to vehicle dynamics. Therefore, having an accurate value of mass is essential for having a suitable model which will lead to proper controller and observer operation. Additionally, unlike other vehicle parameters, the mass can vary during a trip due to loading and unloading items and passengers onto the vehicle, greatly influencing its dynamics. This is critical in heavy vehicles where the mass can vary by around 400%. Therefore, the mass must be updated on-line. The novelty of this paper is the construction of a state-parameter observer which allows the mass under static and dynamic driving conditions to be estimated using measurements from sensors that can be mounted easily on vehicles. In this study, a vertical complete model is considered based on the dual Kalman filter for mass and road irregularities estimation using the data obtained from suspension deflection sensors and a vertical accelerometer. Both simulation and experimental results are carried out to prove the effectiveness of the proposed algorithm.This work was supported by Projects TRA2008-05373/AUT and TRA2013-48030-C2-1-R from the Spanish Ministry of Economy and Competitiveness

Autonomous path following and emergency braking control for intelligent vehicles using low cost devices

Proceeding of: 15th International Symposium on Advanced Vehicle Control (AVEC '22), September 12-15, 2022, Kanagawa, JapanThe novelty of this paper is an Event-Triggered LPV Output-Feedback H∞ controller that generates a steering control signal to follow the road, an acoustic sensor based AEB-P system which avoids vehicle collision with pedestrians and a speed controller based on the curvature of the path. The validation of the proposed system is done through simulation tests with CarSim®This work was supported by the FEDER/Ministry of Science and Innovation - Agencia Estatal de Investigación (AEI) of the Government of Spain through the project [RTI2018-095143-B-C21]

Construcción de un mapa topo-geométrico del entorno y localización de manera simultánea

Cuando un robot móvil autónomo se desplaza por un entorno desconocido, la planificación sólo se puede llevar a cabo si va acompañada de un modelado del entorno. Para construir un mapa del entorno, el robot debe conocer su posición relativa a localizaciones pasadas. Debido a los errores de odometría, que se incrementan a medida que el robot se desplaza, es necesario llevar a cabo un proceso de localización que permita estimar la posición del robot en relación a elementos conocidos. De este modo, el problema de generación de un mapa del entorno es referido frecuentemente como el problema de localización y construcción del mapa de manera simultánea, también conocido como problema SLAM (Simultaneous Localization And Mapping). El método propuesto en esta tesis permite generar un mapa del entorno mientras que el robot se desplaza, al mismo tiempo que se localiza utilizando las características del mapa. Para resolver este problema, el robot, en cada desplazamiento, adquiere información del entorno, a través de un telémetro láser, y almacena la información o do métrica. El entorno es modelado como un grafo, donde los nodos representan lugares típicos de entornos de interiores estructurados, y los arcos representan el camino que unen estos nodos. Tanto los nodos como las ramas son enriquecidos con información geométrica, por lo que el mapa generado es un mapa topo-geométrico. Un Diagrama de Voronoi Local (DVL) es generado directamente a partir de las medidas proporcionadas por un telémetro láser. El diagrama de Voronoi representa el camino, o conjunto de puntos, que son equidistantes a varios objetos presentes en el entorno. De esta manera, el DVL representa el camino más seguro que puede seguir el robot. El mapa topo-geométrico local es generado a partir del DVL. Este mapa no contiene solamente información topológica, sino que también contiene información geométrica, como es la posición de los nodos y los puntos que caracterizan las ramas. El algoritmo SLAM presentado en esta tesis alterna dos pasos: 1) un paso de localización y 2) un paso de generación del mapa. El primer paso estima la mejor posición del robot, considerando que los mapas locales no poseen errores, mientras que el segundo paso genera el mapa global del entorno utilizando las posiciones estimadas en el paso anterior. El paso de localización utiliza algoritmos genéticos para estimar la posición del robot, contrastando los mapas locales obtenidos en cada nueva posición del robot. La información, tanto topo-geométrica del mapa como odométrica, son utilizadas para estimar la posición del robot y eliminar posibles ambigüedades presentes en el entorno. El algoritmo de localización alterna dos pasos: 1) un paso hacia adelante y 2) un paso hacia atrás. El paso hacia adelante estima la posición actual del robot. El paso hacia atrás estima todas las posiciones del robot. El algoritmo hacia adelante se ejecuta en cada nuevo desplazamiento del robot, mientras que, el algoritmo hacia atrás solo se ejecuta cuando se cierra un ciclo, es decir, cuando el robot vuelve a pasar por una zona de la que ya tiene información. Este paso de corrección de las posiciones estimadas en instantes de tiempo anteriores hace que el algoritmo dé resultados buenos en entornos de grandes dimensiones con ciclos El mapa topo-geométrico global es construido integrando la información de los mapas locales obtenidos en cada nueva posición del robot, utilizando las posiciones estimadas en el paso de localización. Este mapa contiene información tanto topológica (nodos y ramas que unen estos nodos) como geométrica (posición de los nodos, puntos que caracterizan las ramas, y distancias de estos puntos a los objetos equidistantes). La ventaja de este mapa topo-geométrico es que puede ser utilizado para desarrollar varias tareas como son navegación, planificación y localización. Los resultados experimentales, llevados a cabo en entornos de interiores de grandes dimensiones con ciclos, muestran la robustez y eficacia del algoritmo desarrollado para resolver el problema SLAM.When an autonomous mobile robot moves in an unknown environment, the path planning can only be performed if there is a modeled environment. In order to build a map of the environment, a robot must know where it is relative to past locations. Due to errors in odometry, which are acumulative, it is necessary to localize the robot in relation to already known elements. Thus the problem of mapping is often referred to as Simultaneous Localization And Mapping (SLAM). The proposed method allows to build a map of the environment and to use the map to self-localize simultaneously. In order to resolve this problem, in each displacement, the robot takes a sean with the laser telemeter and simultaneously stores the odometric information. The environment is modeled as a graph, in a topo-geometric form, where each node corresponds to a distinctive place, and the ares are paths which join the nodes. This graph is generated from a Local Voronoi Diagram (LVD), that is built from measurements of the laser telemeter. The Voronoi Diagram represents the way, or set of points which are equidistants to different objects in the environment. In this manner, the LVD is thought to be the safest way to move the robot. The local topo-geometric map is generated from LVD directly. This map contains not only topological information but also contains geometric information, such as, the nodes position and the edges' points. This thesis propases a new SLAM method, which alternates two steps: 1) a localization step and 2) a mapping step. This process is executed every time the robot is displacing. The first step computes the best robot's position, based on the local maps ( the best available). The second step genera tes the global map using the estimated locations in the previous step. The localization step uses genetic algorithms to estímate the robot's position, matching local topo-geometric maps, which are obtained in each robot's displacement. The topological and geometric information, and the odometric measurements are used to estímate the robot's position and resolve posible ambiguities. The localization algorithm combines two steps: 1) a forward step and 2) a backward step. The forward step estimates the current robot's position, while the backward step revises a full posterior over poses. The forward step is executed in each iteration, but the backward step is executed only when closing the environment scanning cycle. The global topo-geometric map is built matching the local topo-geometric maps and making use of the estimated locations in the previous step. This map not only contains topological information, like representative places ( doors, hallways, etc.), but also contains their position. The topo-geometric map is used to execute different tasks such as navigation, path planning and localization. Experimental results in large and cyclic indoor environments demostrate that our approach is well suited to resolve the SLAM problem.Doctor por la Universidad Carlos III de Madrid. Programa en Tecnologías IndustrialesPresidenta: Carlos Balaguer Bernaldo de Quirós.- Secretario: José María Armingol Moreno.- Vocales: Luis Montano Gella, Juan López Coronado y Fernando Mati

Simultaneous Estimation of Vehicle Sideslip and Roll Angles Using an Integral-Based Event-Triggered Hinfinity Observer Considering Intravehicle Communications

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.This work was supported by the Agencia Estatal de Investigacion (AEI) of the Ministry of Science and Innovation of the Government of Spain through the project RTI2018-095143-B-C2

Experimental study and analytical model of bleed valve orifice influence of a high-performance shock absorber on vehicle dynamics

The aim of this study is to model the influence of the bleed orifice area of a high-performance damper on the dynamic behaviour of a vehicle. For this purpose, a mathematical model of a monotube high-performance damper is developed, considering the presence of two regulation ways on the effect of bleed valve orifice of the damper. An application of changes in damper setup in the field of practical enables to analyse the influence of the positions of both rod and bottle selectors on the damping force. The proposed damper model is validated experimentally. The analysis of the dynamic behaviour is performed through a quarter vehicle simulation under different conditions of road roughness and speed regimes. In addition, an analysis of the frequency response of the sprung mass acceleration by means of power spectral density was applied to obtain the dynamic response of the quarter vehicle model. Results show that the influence of the bleed orifice is magnified for low speeds and for profile roads with few variations on surface. This effect is reduced for both the increasing vehicle speed and the profiles with greater difference in irregularities