TY - JOUR AU - Beregi, Sándor AU - Barton, David A. W. AU - Rezgui, Djamel AU - Neild, Simon TI - Using scientific machine learning for experimental bifurcation analysis of dynamic systems JF - MECHANICAL SYSTEMS AND SIGNAL PROCESSING J2 - MECH SYST SIGNAL PR VL - 184 PY - 2023 PG - 16 SN - 0888-3270 DO - 10.1016/j.ymssp.2022.109649 UR - https://m2.mtmt.hu/api/publication/33432672 ID - 33432672 AB - Augmenting mechanistic ordinary differential equation (ODE) models with machine-learnable structures is a novel approach to create highly accurate, low-dimensional models of engineering systems incorporating both expert knowledge and reality through measurement data. Our exploratory study focuses on training universal differential equation (UDE) models for physical nonlinear dynamical systems with limit cycles: an aerofoil undergoing flutter oscillations and an electrodynamic nonlinear oscillator. We consider examples where training data is generated by numerical simulations, whereas we also employ the proposed modelling concept to physical experiments allowing us to investigate problems with a wide range of complexity. To collect the training data, the method of control-based continuation is used as it captures not just the stable but also the unstable limit cycles of the observed system. This feature makes it possible to extract more information about the observed system than the open-loop approach (surveying the steady state response by parameter sweeps without using control) would allow. We use both neural networks and Gaussian processes as universal approximators alongside the mechanistic models to give a critical assessment of the accuracy and robustness of the UDE modelling approach. We also highlight the potential issues one may run into during the training procedure indicating the limits of the current modelling framework. LA - English DB - MTMT ER - TY - JOUR AU - Beregi, Sándor AU - Avedisov, Sergei S AU - He, Chaozhe R AU - Takács, Dénes AU - Orosz, Gábor TI - Connectivity-Based Delay-Tolerant Control of Automated Vehicles: Theory and Experiments JF - IEEE Transactions on Intelligent Vehicles J2 - IEEE Transactions on Intelligent Vehicles VL - 8 PY - 2023 IS - 1 SP - 275 EP - 289 PG - 15 SN - 2379-8858 DO - 10.1109/TIV.2021.3131957 UR - https://m2.mtmt.hu/api/publication/32653366 ID - 32653366 N1 - Budapest University of Technology and Economics, Department of Applied Mechanics, Budapest, H-1111, Hungary University of Bristol, Department of Engineering Mathematics, Bristol, BS8 1TW, United Kingdom University of Michigan, Department of Mechanical Engineering, Ann Arbor, MI 48109, United States Toyota Motor North America R&D - Infotech Labs, Mountain View, CA 94043, United States Plus.ai Inc., Cupertino, CA 95014, United States MTA-BME Research Group on Dynamics of Machines and Vehicles, Budapest, H-1111, Hungary University of Michigan, Department of Civil and Environmental Engineering, Ann Arbor, MI 48109, United States Correspondence Address: Takacs, D.; Budapest University of Technology and Economics, Hungary; email: takacs@mm.bme.hu AB - The concept of utilizing vehicle-to-everything (V2X) connectivity to improve the resilience of automated vehicles in an environment where optical sensors may not provide reliable data is investigated. Longitudinal and lateral controllers are designed to enable a connected automated vehicle (CAV) to utilize V2X information from nearby connected human-driven vehicles (CHVs). The linear stability of the controllers are investigated theoretically while taking into account the time delays in the feedback loops. Novel performance measures are introduced to quantify the plant and string stability properties of the longitudinal controller from experimental data. The stability of the lateral controller is also evaluated in lane-keeping experiments. The robustness of the designed controllers against latency is demonstrated and the performance of the overall systems is showcased experimentally using real vehicles on a test track. LA - English DB - MTMT ER - TY - JOUR AU - Beregi, Sándor TI - Nonlinear analysis of the delayed tyre model with control-based continuation JF - NONLINEAR DYNAMICS J2 - NONLINEAR DYNAM VL - 110 PY - 2022 SP - 3151 EP - 3165 PG - 15 SN - 0924-090X DO - 10.1007/s11071-022-07796-7 UR - https://m2.mtmt.hu/api/publication/33169041 ID - 33169041 AB - In this study, the numerical bifurcation analysis of a shimmying wheel is performed with a non-smooth, time-delayed model of the tyre-ground contact. This model is capable of reproducing the bistable behaviour often observed in experiments: a stable equilibrium and a stable periodic orbit coexisting for the same set of system parameters, that the simpler quasi-steady tyre models fail to capture. In the bistable parameter domain, there also exists an unstable periodic orbit within the separatrix between the domains of attractions of the two stable steady-state solutions. Although this solution never appears in a real-life system, one may still gain valuable information from tracing it as it gives an indication about the level of perturbation that would drive the system from one stable solution to the other. However, the complexity of the laws governing partial sticking and sliding in the tyre-ground contact makes the numerical bifurcation analysis with the traditional, collocation-based techniques infeasible. Instead, this study is based on numerical simulations and the technique of control-based continuation (CBC) to track the stable and unstable periodic solutions of the system allowing for the assessment of the accuracy of the non-smooth, delayed tyre model in replicating the dynamics observed in experiments. In the meantime, the physics-based model provides an insight into the relationship between the sticking and sliding regions appearing in the tyre-ground contact and the global dynamics of the system. LA - English DB - MTMT ER - TY - JOUR AU - Bonney, Matthew S. AU - de Angelis, Marco AU - Dal Borgo, Mattia AU - Andrade, Luis AU - Beregi, Sándor AU - Jamia, Nidhal AU - Wagg, David J. TI - Development of a digital twin operational platform using Python Flask JF - Data-Centric Engineering J2 - DCE VL - 3 PY - 2022 SN - 2632-6736 DO - 10.1017/dce.2022.1 UR - https://m2.mtmt.hu/api/publication/32653362 ID - 32653362 N1 - Export Date: 3 June 2022 LA - English DB - MTMT ER - TY - JOUR AU - Beregi, Sándor AU - Barton, David A. W. AU - Rezgui, Djamel AU - Neild, Simon A. TI - Robustness of nonlinear parameter identification in the presence of process noise using control-based continuation JF - NONLINEAR DYNAMICS J2 - NONLINEAR DYNAM VL - 104 PY - 2021 IS - 2 SP - 885 EP - 900 PG - 16 SN - 0924-090X DO - 10.1007/s11071-021-06347-w UR - https://m2.mtmt.hu/api/publication/32653456 ID - 32653456 LA - English DB - MTMT ER - TY - THES AU - Beregi, Sándor TI - Delay effects and non-smoothness in the dynamic tyre-road contact and vehicle steering [Időkésés és nem-sima hatások a dinamikus kerék-talaj kontaktban és a járművek kormányzásában] PB - Budapesti Műszaki és Gazdaságtudományi Egyetem PY - 2019 SP - 97 UR - https://m2.mtmt.hu/api/publication/31262490 ID - 31262490 LA - English DB - MTMT ER - TY - JOUR AU - Beregi, Sándor AU - Takács, Dénes AU - Stépán, Gábor TI - Correction to:Bifurcation analysis of wheel shimmy with non-smooth effects and time delay in the tyre-ground contact (vol 98, pg 841, 2019) JF - NONLINEAR DYNAMICS J2 - NONLINEAR DYNAM VL - 98 PY - 2019 IS - 1 SP - 859 EP - 859 PG - 1 SN - 0924-090X DO - 10.1007/s11071-019-05207-y UR - https://m2.mtmt.hu/api/publication/31087126 ID - 31087126 LA - English DB - MTMT ER - TY - JOUR AU - Beregi, Sándor AU - Takács, Dénes AU - Gyebrószki, Gergely AU - Stépán, Gábor TI - Theoretical and experimental study on the nonlinear dynamics of wheel-shimmy JF - NONLINEAR DYNAMICS J2 - NONLINEAR DYNAM VL - 4 PY - 2019 SP - 2581 EP - 2593 PG - 13 SN - 0924-090X DO - 10.1007/s11071-019-05225-w UR - https://m2.mtmt.hu/api/publication/30893747 ID - 30893747 LA - English DB - MTMT ER - TY - JOUR AU - Beregi, Sándor AU - Takács, Dénes AU - Stépán, Gábor TI - Bifurcation analysis of wheel shimmy with non-smooth effects and time delay in the tyre–ground contact JF - NONLINEAR DYNAMICS J2 - NONLINEAR DYNAM VL - 98 PY - 2019 IS - 1 SP - 841 EP - 858 PG - 18 SN - 0924-090X DO - 10.1007/s11071-019-05123-1 UR - https://m2.mtmt.hu/api/publication/30840377 ID - 30840377 N1 - Funding Agency and Grant Number: National Research, Development and Innovation Office [NKFI-128422] Funding text: This research was funded by the National Research, Development and Innovation Office under Grant No. NKFI-128422. Export Date: 28 November 2019 CODEN: NODYE LA - English DB - MTMT ER - TY - CHAP AU - Beregi, Sándor AU - Takács, Dénes AU - Stépán, Gábor TI - Theoretical and experimental study on the nonlinear dynamics of wheel-shimmy T2 - NODYCON Book of abstracts PB - Sapienza University of Rome CY - Roma SN - 9788894422900 PY - 2019 SP - 477 EP - 478 PG - 2 UR - https://m2.mtmt.hu/api/publication/30624168 ID - 30624168 LA - English DB - MTMT ER -