J. Bokor

7102304229

Publications - 18

Nonlinear Identification of Lateral Dynamics of an Autonomous Car Vehicle †

Dániel Pup György Istenes Ferenc Szauter J. Bokor

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

In this paper, the nonlinear identification of the lateral dynamics of a road vehicle and the velocity dependence of the dynamics are presented. One of the most useful methods to define the mathematical model is system identification based on measured data. A test vehicle for autonomous driving was constrained to move in a straight line while the vehicle’s steering servo was artificially excited. The input of the system is therefore the sum of the artificial excitation and the control signal of the autonomous function, and the output is the lateral acceleration of the vehicle. The measurements are used to identify Wiener and Hammerstein models of the lateral dynamics at different speeds using nonlinear methods. The aim is to investigate the velocity dependence of the dynamics.

Open Access: Yes

DOI: 10.3390/engproc2024079053

Learning Nonlinear Models of Dynamic Systems

Zoltán Szabó J. Bokor

Publication Name: Sisy 2024 IEEE 22nd International Symposium on Intelligent Systems and Informatics Proceedings

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 11-15

Description:

Modeling dynamic systems is an important part in analysing and control of various systems arising either in health sciences or in the engineering word. Recent approaches to learn models from data are the so-called kernel-based methods and SVMs. There are strong relations to the theory of reproducing kernel Hilbert space (RKHS), to principal component analysis and canonic correlation analysis known previously from statistics. In recent form their use was extended from statistics to obtain models for dynamic systems. First we summarise the basics for the reproducing kernel based Hilbert space (RKHS) and the support vector machine (SVM) approaches. Following this it will be shown how some frequently used nonlinear models can be obtained by using these concepts. In the last part we discuss the structure estimation problem, i.e. how to determine the (least) number of features (observables) to describe the nonlinear system with a sparse representation.

Open Access: Yes

DOI: 10.1109/SISY62279.2024.10737570

Hammerstein Model Identification for Autonomous Vehicle Dynamics by Two-Stage Algorithm †

György Terdik Dániel Pup György Istenes J. Bokor

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

In this paper, the nonlinear identification (ID) of the lateral dynamics of a road vehicle is presented. The mathematical description of lateral dynamics is crucial for developing various self-driving functions. One method of describing dynamics is system identification from measured data. During the measurements, the steering servo of a test vehicle kept in straight-line motion by a self-driving function was artificially excited. A Hammerstein–Wiener model was successfully applied for the identification of these measurements. A nonlinear estimator was used during the fitting, which needed high computing power. For the Hammerstein–Wiener model, we used the two-stage algorithm (TSA) with a bilinear estimation method, which makes it possible to apply linear regression. We compared these methods during simulations and real data.

Open Access: Yes

DOI: 10.3390/engproc2024079054

Data-driven linear parameter-varying modelling of the steering dynamics of an autonomous car

Gabor Rodonyi R. Tóth Peter Koros Dániel Pup Ádám Kisari Zsombor Vigh J. Bokor

Publication Name: IFAC Papersonline

Publication Date: 2021-07-01

Volume: 54

Issue: 8

Page Range: 20-26

Description:

Developing automatic driving solutions and driver support systems requires accurate vehicle specific models to describe and predict the associated motion dynamics of the vehicle. Despite of the mature understanding of ideal vehicle dynamics, which are inherently nonlinear, modern cars are equipped with a wide array of digital and mechatronic components that are difficult to model. Furthermore, due to manufacturing, each car has its personal motion characteristics which change over time. Hence, it is important to develop data-driven modelling methods that are capable to capture from data all relevant aspects of vehicle dynamics in a model that is directly utilisable for control. In this paper, we show how Linear Parameter-Varying (LPV) modelling and system identification can be applied to reliably capture personalised model of the steering system of an autonomous car based on measured data. Compared to other nonlinear identification techniques, the obtained LPV model is directly utilisable for powerful controller synthesis methods of the LPV framework.

Open Access: Yes

DOI: 10.1016/j.ifacol.2021.08.575

Identification of the nonlinear steering dynamics of an autonomous vehicle

Gabor Rodonyi R. Tóth M. Schoukens Peter Koros Dániel Pup Ádám Kisari G. I. Beintema Zsombor Vigh Alexandros Soumelidis J. Bokor

Publication Name: IFAC Papersonline

Publication Date: 2021-07-01

Volume: 54

Issue: 7

Page Range: 708-713

Description:

Automated driving applications require accurate vehicle specific models to precisely predict and control the motion dynamics. However, modern vehicles have a wide array of digital and mechatronic components that are difficult to model, manufactures do not disclose all details required for modelling and even existing models of subcomponents require coefficient estimation to match the specific characteristics of each vehicle and their change over time. Hence, it is attractive to use data-driven modelling to capture the relevant vehicle dynamics and synthesise model-based control solutions. In this paper, we address identification of the steering system of an autonomous car based on measured data. We show that the underlying dynamics are highly nonlinear and challenging to be captured, necessitating the use of data-driven methods that fuse the approximation capabilities of learning and the efficiency of dynamic system identification. We demonstrate that such a neural network based subspace-encoder method can successfully capture the underlying dynamics while other methods fall short to provide reliable results.

Open Access: Yes

DOI: 10.1016/j.ifacol.2021.08.444

Characterization of Model Uncertainty Features Relevant to Model Predictive Control of Lateral Vehicle Dynamics

Gabor Rodonyi Dániel Pup Ádám Kisari Zsombor Vigh Alexandros Soumelidis J. Bokor

Publication Name: 2020 23rd IEEE International Symposium on Measurement and Control in Robotics Ismcr 2020

Publication Date: 2020-10-15

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The information about a system's dynamics represented by measurement data sets are often confined to regions of restricted operations where the system is not sufficiently excited for model identification purposes. Experiments performed in closed-loop with safety constraints allow only for reduced order modeling. In the paper, a set of low order models are identified from real experimental data of the lateral dynamics of an electric passenger car. Low order models are advantageous for on-line computation in model-based control, though uncertainty due to neglected dynamics may deteriorate control performance and constraint satisfaction. The effect of uncertainty is analyzed by controller cross-validation where a controller designed based on one model is evaluated on other models playing the role of the true system. This method allows us to qualify not only model-controller pairs, but to determine the properties of input data and model uncertainty, which lead to more useful data sets, more robust and better performing controllers than the others.

Open Access: Yes

DOI: 10.1109/ISMCR51255.2020.9263745

Experimental verification of a control system for autonomous navigation

Gabor Rodonyi Peter Koros Dániel Pup Ádám Kisari Benedek Szucs Alexandros Soumelidis J. Bokor

Publication Name: IFAC Papersonline

Publication Date: 2020-01-01

Volume: 53

Issue: 2

Page Range: 14273-14278

Description:

A flexible architecture is developed with the purpose of supporting education and research on the field of autonomous vehicles. A pure electric vehicle is equipped with on-board computational units, sensors and actuator interfaces. This paper presents the current status of the control system and its validation by means of navigation experiments. With the cascade control architecture, problems of actuator dead-zone, sensor offset errors, path tracking and redesign for obstacle avoidance are addressed.

Open Access: Yes

DOI: 10.1016/j.ifacol.2020.12.1171

Structure Selection and LPV Model Identification of a Car Steering Dynamics⁎

Gabor Rodonyi Zoltán Szabó Peter Koros Dániel Pup Alexandros Soumelidis J. Bokor

Publication Name: Unknown

Publication Date: 2018-01-01

Volume: 51

Issue: 15

Page Range: 1086-1091

Description:

A Linear Parameter-Varying (LPV), discrete-time black box model of an electric power assisted steering system of a passenger car is identified from open-loop step response measurement data. The goal is to provide a nominal model for control design and analysis that is able to describe the principal characteristics of the system in the whole region of steering angle and speed range of 3 to 30 km/h. Examining a set of experimental data by using classical linear time-invariant black box modeling and validation techniques, the structure of the LPV model is determined. The parameters of the model are identified based on minimizing a quadratic error criterion by nonlinear optimization algorithms.

Open Access: Yes

DOI: 10.1016/j.ifacol.2018.09.049

Robust reconfigurable control for in-wheel electric vehicles

Tímea Fülep András Mihály Zoltán Szabó Péter Gáspár Ferenc Szauter J. Bokor

Publication Name: IFAC Papersonline

Publication Date: 2015-09-01

Volume: 28

Issue: 21

Page Range: 36-41

Description:

The paper presents a fault tolerant reconfigurable control method for vehicles driven by four in-wheel electric motors and a steering system. The aim of the design is to realize robust velocity and road trajectory tracking even under challenging driving conditions or actuator failures. The vehicle is operated solely with the in-wheel motors, thus steering intervention is only applied in case of skidding or a failure of an electric motor. The reconfigurable control is realized based on Linear Parameter Varying (LPV) framework, using the specific characteristics of the in-wheel motors of fast and accurate torque control. The operation of the designed control system is demonstrated in a CarSim simulation environment.

Open Access: Yes

DOI: 10.1016/j.ifacol.2015.09.501

Complex analysis of the dynamic effects of car population along the trajectories

Tamas Péter Ferenc Szauter J. Bokor

Publication Name: Proceedings of the ASME Design Engineering Technical Conference

Publication Date: 2015-01-01

Volume: 9

Issue: Unknown

Page Range: Unknown

Description:

The analyses apply new complex model to analyze both road traffic transport processes and spatial nonlinear vehicle dynamic effects. Therefore also the network traffic processes can be analyzed and in a united system the spatial vehicle dynamic processes realized on networks can be attained. Objective the raising the dynamic safety, risk and hazard analysis, reducing the environmental impact of vehicles.

Open Access: Yes

DOI: 10.1115/DETC2015-47075

Hierarchical robust control for in-wheel motor vehicles

Tímea Fülep Péter Gáspár András Mihály Zoltán Szabó Ferenc Szauter J. Bokor

Publication Name: Proceedings of the Mini Conference on Vehicle System Dynamics Identification and Anomalies

Publication Date: 2014-01-01

Volume: 2014-January

Issue: Unknown

Page Range: 71-81

Description:

The paper proposes the design of an integrated vehicle control system for in-wheel electric vehicle, which is able to track road geometry with a predefined reference velocity. In the design the lateral and longitudinal dynamics are combined using the in-wheel motors and the steering system. The design methodology of the hierarchical control is proposed. The required control signals are calculated by applying high-level controllers, which are designed using a robust control method. For the control design the model is augmented with weighting functions specified by the performance demands. The actuators generating the necessary control signals in order to achieve the requirements for which low-level tracking controllers are designed.

Open Access: Yes

DOI: DOI not available

Robust reconfigurable control for in-wheel motor vehicles

Tímea Fülep Péter Gáspár András Mihály Zoltán Szabó Ferenc Szauter J. Bokor

Publication Name: 2014 IEEE International Electric Vehicle Conference Ievc 2014

Publication Date: 2014-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The paper deals with reconfigurable control of in-wheel electric vehicles. Basically the vehicle is controlled alone by the four electric engines mounted in the wheels of the vehicle. The goal is to design a control system with velocity and trajectory tracking ability realized by separate torque generation of the in-wheel motors. In critical driving situations when the yaw moment cannot be established with the four in-wheel engine alone, the high-level controller reconfigures the actuator inputs, thus steering intervention helps to stabilize the vehicle. Moreover, a multi-layer supervisory architecture for integrated control systems is also proposed. The operation of the vehicle is illustrated through a CarSim simulation example.

Open Access: Yes

DOI: 10.1109/IEVC.2014.7056232

Number archetypes, symbolic coding letters and "background communication theory" in Saint Stephen's royal mirror

P. Várlaki J. Bokor

Publication Name: Iccc 2009 IEEE 7th International Conference on Computational Cybernetics

Publication Date: 2009-12-01

Volume: Unknown

Issue: Unknown

Page Range: 201-211

Description:

Following Pauli's approach to the analysis of the Kepler's works, the paper attempts to identify patterns in the creative background cognitive processes related to a "background system and communication theory" in the thousand-year-old great Latin opus of St Stephen's Royal Mirror. Our paper is dedicated to the blessed memory of Prof. S. Csibi, the great scholar of communication theory, who creatively participated in this endeavour. ©2009IEEE.

Open Access: Yes

DOI: 10.1109/ICCCYB.2009.5393934

"System identification" and hermeneutics for long run series of synchronicities in the Pauli-Jung relationship

P. Várlaki I. J. Rudas J. Bokor

Publication Name: Iccc 2009 IEEE 7th International Conference on Computational Cybernetics

Publication Date: 2009-12-01

Volume: Unknown

Issue: Unknown

Page Range: 129-140

Description:

The paper discusses some characteristic symbolic patterns which can be identified in the long run series of synchronicities in the Pauli-Jung cooperation concerning the long run dream series of Pauli. We try to show the paradigm of the modern system and control theory in the typical identifiable structures and symbolic patterns of dreams and synchronistic phenomena using the contemporary and old approaches of Hermeneutics. ©2009IEEE.

Open Access: Yes

DOI: 10.1109/ICCCYB.2009.5393949

Number archetypes and "background" control theory concerning the fine structure constant

P. Várlaki László Nádai J. Bokor

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2008-12-01

Volume: 5

Issue: 2

Page Range: 71-104

Description:

In this paper we analyze in detail the central role of number '137', the so-called Fine Structure Constant in the collaboration of Pauli and Jung. First, we present the fascination or the obsession of Pauli for the interpretation of number '137'. Second, we treat the spontaneous messages originating from unconscious concerning number '137' in the wellknown dreams of Pauli. We restrict our investigations to the dreams containing the especially important formulae of Fine Structure Constant (4π3 + π2 + π), and also that containing the so-called background models of mathematical control systems. Third, we shortly mention four of the numerous synchronicities arising during the Pauli-Jung collaboration.

Open Access: Yes

DOI: DOI not available

Number archetypes in system realization theory concerning the fine structure constant

P. Várlaki László Nádai J. Bokor

Publication Name: 12th International Conference on Intelligent Engineering Systems Proceedings Ines 2008

Publication Date: 2008-09-02

Volume: Unknown

Issue: Unknown

Page Range: 83-92

Description:

In this paper we analyze in detail the central role of number '137', the so-called Fine Structure Constant in the collaboration of Pauli and Jung. First, we present the fascination or the obsession of Pauli for the interpretation of number '137'. Second, we treat the spontaneous messages originating from unconscious concerning number '137' in the well-known dreams of Pauli. We restrict our investigations to the dreams containing the especially important formulae of Fine Structure Constant (4π3 + π2 + π), and also that containing the so-called background models of mathematical control systems. Third, we shortly mention four of the numerous synchronicities arising during the Pauli-Jung collaboration. © 2008 IEEE.

Open Access: Yes

DOI: 10.1109/INES.2008.4481274

Numbers and system representations in perspective of the Pauli-Jung correspondence

P. Várlaki László Nádai J. Bokor

Publication Name: Sami 2008 6th International Symposium on Applied Machine Intelligence and Informatics Proceedings

Publication Date: 2008-08-25

Volume: Unknown

Issue: Unknown

Page Range: 11-18

Description:

The paper deals with the basic features of the so-called synchronistic stochastic (control) systems on the basis of the extended Kalmanian system and realization theory, using the synchronicity paradigm of Jung and Pauli. It is shown that the introduced additive geometric structure number (characterizing the representation structure of synchronistic stochastic systems) is theoretically equivalent to the fine structure constant (determining e.g. the fine structure of hydrogen spectra) redefined by the authors of this paper. Finally the redefined form of fine structure constant as additive structure number (mediator number or identificator number) and the amplified interpretation of structural patterns of some important objects of cultural history, as well as the hypothetically related natural and geometric structure numbers, are compared. © 2008 IEEE.

Open Access: Yes

DOI: 10.1109/SAMI.2008.4469164

Integrated robust control design for in-wheel-motor vehicles

Tímea Fülep Zoltán Szabó Péter Gáspár Mihály András Ferenc Szauter J. Bokor

Publication Name: Fisita 2014 World Automotive Congress Proceedings

Publication Date: 2014-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The paper proposes a multi-layer supervisory architecture for integrated control systems in road vehicles. The role of the supervisor is to coordinate active control components and provide priority among them. The supervisor has information about the current operational mode of the vehicle and it is able to make decisions about the necessary interventions into the vehicle components and guarantee the reconfigurable operation of the vehicle. The decisions of the supervisor are propagated to the lower layers through predefined interfaces encoded as suitable scheduling signals. The contribution of the paper is the application of the LPV methodology in a design case study in which an integrated control of four wheel independently-actuated electric vehicle with active steering system is developed.

Open Access: Yes

DOI: DOI not available