TY - JOUR AU - Chen, Jingtian AU - Lu, Shaoyi AU - Zhang, Li AU - Insperger, Tamás AU - Stépán, Gábor TI - Adjoint sensitivity method for parameter estimation: applications to inverted pendulum and human standing balance JF - JOURNAL OF THE ROYAL SOCIETY INTERFACE J2 - J R SOC INTERFACE VL - 22 PY - 2025 IS - 227 PG - 18 SN - 1742-5689 DO - 10.1098/rsif.2024.0843 UR - https://m2.mtmt.hu/api/publication/36217357 ID - 36217357 N1 - Funding Agency and Grant Number: National Natural Science Foundation of China Funding text: We sincerely appreciate the discussions with Prof. Huailei Wang (Nanjing University of Aeronautics and Astronautics) and the colleagues who provided valuable suggestions for this study. AB - The inverted pendulum, a classical mechanical system, often serves as a platform for studying stability and control algorithms. Modelling human standing balance as an inverted pendulum controlled by the time-delayed proportional-derivative (PD) feedback controller can be used effectively to study the related biomechanical mechanisms. In this study, to investigate the human balance control strategy, an adjoint sensitivity analysis method and a corresponding optimizer are implemented to directly determine system parameters, control gains and the time delay in the human balancing model. This study validates the accuracy of the optimizer through numerical simulations and experimental verification based on the physical model of the inverted pendulum on a cart. The experimental results confirm the performance of the identification algorithm for systems involving non-smooth dynamics and inherent time delays. Moreover, the identification based on human balance data indicates that the time-delayed PD feedback controller effectively represents the human balance control strategy. Additionally, the identification reveals a tendency in the control strategy: the control gains are located in the lower-left region of the stability diagram, indicating that the human body tends to adopt an optimal control strategy that minimizes energy consumption. LA - English DB - MTMT ER - TY - CHAP AU - Milton, John AU - Insperger, Tamás ED - Mori, Yoichiro ED - Perthame, Benoît ED - Stevens, Angela TI - Why Does a Stick Balanced on the Fingertip Fall? T2 - Dynamics of Physiological Control PB - Springer Nature Switzerland CY - Cham SN - 9783031823961 T3 - Lecture Notes on Mathematical Modelling in the Life Sciences, ISSN 2193-4789 PY - 2025 SP - 149 EP - 161 PG - 13 DO - 10.1007/978-3-031-82396-1_8 UR - https://m2.mtmt.hu/api/publication/36328232 ID - 36328232 N1 - Michael Mackey has been a dear friend and colleague of JM for over 47 years. We acknowledge that we have been able to learn from the experiences of many “pole balancing” collaborators including Juan Luis Cabrera (Universidad Politécnica de Madrid, Spain), Andre Longtin (University of Ottawa), Toru Ohira (Nagoya University, Japan), and from the Budapest University of Technology and Economics, Hungary (Gabor Csernak, Gabor Stepan and their students). In addition, JM acknowledges the 38 students at the Claremont Colleges who wrote senior theses on topics related to stick balancing and the 66 students who learned to stick balance. TI acknowledges support from the National Research, Development and Innovation Office (Grant No. NKFI-K138621). AB - An inverted pendulum can be fully stabilized using time-delayed feedback. In contrast, for human stick balancers the stick always falls. It is suggested that stick falls are a consequence transient micro-chaotic dynamics which naturally arises because of the interplay between time-delayed feedback, a sensory dead zone and the frequency-dependent encoding of force. LA - English DB - MTMT ER - TY - JOUR AU - Lu, Shaoyi AU - Chen, Jingtian AU - Li, Huifang AU - Zhang, Li AU - Insperger, Tamás AU - Stépán, Gábor TI - A switched optimal control strategy in human balancing on a harmonically moving platform JF - JOURNAL OF BIOMECHANICS J2 - J BIOMECH VL - 191 PY - 2025 PG - 9 SN - 0021-9290 DO - 10.1016/j.jbiomech.2025.112923 UR - https://m2.mtmt.hu/api/publication/36339102 ID - 36339102 N1 - Funding Agency and Grant Number: National Natural Science Foundation of China [12272167]; National Research, Development and Innovation Office of Hungary [NKFI-K138621]; HUN-REN Hungarian Research Network Funding text: This work was supported in part by the National Natural Science Foundation of China [Grant no. 12272167] , the National Research, Development and Innovation Office of Hungary [Grant no. NKFI-K138621] and the HUN-REN Hungarian Research Network. We are grateful to Bauer Balazs for his help in improving the language and clarity of the manuscript. AB - Postural balance is crucial for human daily activities, and understanding the neural-motor control mechanisms underlying balance performance is essential for improving diagnosis and intervention strategies for balance disorders. This study focuses on the human standing balance task on a harmonically moving platform with anterior-posterior translation, exploring the neural-motor control logic using a switched control strategy. It is hypothesized that humans switch between optimal energy gains and optimal decay gains to maintain balance in a safe and energy-efficient manner with the usage of optimal decay gains being closely related to balancing ability. A two-stage identification process is employed to determine switching time instances, starting with the adjoint method to estimate control gains and followed by the enumeration of gain switching instances. The proposed postural stability assessment indices, Control Strategy Ratio and Control Switch Frequency, offer clear physical interpretations and dynamic insights, demonstrating better consistency and sensitivity compared to some stabilometry parameters. These indices show potential for early diagnosis and intervention in balance disorders. LA - English DB - MTMT ER - TY - JOUR AU - Balogh, Tamás AU - Insperger, Tamás TI - Extending the admissible control-loop delays for the inverted pendulum by fractional-order proportional-derivative controller JF - JOURNAL OF VIBRATION AND CONTROL J2 - J VIB CONTROL VL - 30 PY - 2024 IS - 11-12 SP - 2596 EP - 2604 PG - 9 SN - 1077-5463 DO - 10.1177/10775463231181662 UR - https://m2.mtmt.hu/api/publication/34040356 ID - 34040356 N1 - Funding text: The author(s) disclosed receipt of the following financial supportfor the research, authorship, and/or publication of this article: The research reported in this paper has been supported by Project no.TKP-9-8/PALY-2021 provided by the Ministry of Culture and Innovation of Hungary from the National Research, Developmentand Innovation Fund,financed under the TKP2021-EGA funding scheme, by the Nemzeti Kutatasi Fejlesztesies Innovacios Hivatal(Grant nos. NKFI-K138621 and BME-NVA-02) and by the UNKP-22-3-II-BME-98 New National Excellence Program of the Ministry for Culture and Innovation from the source of theNemzeti Kutatasi Fejlesztesies Innovacios Hivatal. AB - Stabilization of the inverted pendulum by fractional-order proportional-derivative (PD) feedback with two delays is investigated. This feedback law is obtained as a combination of PD feedback with two delays and fractional-order PD feedback with a single delay. Different types of stabilizability boundaries and the corresponding geometric and multiplicity conditions are determined using the D-subdivision method. The stabilizable region is depicted in the plane of the delay parameters for given fractional derivative orders. Several special cases and the concept of delay detuning are also discussed. It is shown that the admissible delay can be slightly increased compared to the integer-order PD feedback by introducing a fractional-order feedback term. LA - English DB - MTMT ER - TY - JOUR AU - Debnath, Minakshi AU - Chang, Joshua AU - Bhandari, Keshav AU - Nagy, Dalma AU - Insperger, Tamás AU - Milton, John G. AU - Ngu, Anne H. H. TI - Pole balancing on the fingertip: model-motivated machine learning forecasting of falls JF - FRONTIERS IN PHYSIOLOGY J2 - FRONT PHYSIOL VL - 15 PY - 2024 PG - 13 SN - 1664-042X DO - 10.3389/fphys.2024.1334396 UR - https://m2.mtmt.hu/api/publication/34767934 ID - 34767934 AB - Introduction: There is increasing interest in developing mathematical and computational models to forecast adverse events in physiological systems. Examples include falls, the onset of fatal cardiac arrhythmias, and adverse surgical outcomes. However, the dynamics of physiological systems are known to be exceedingly complex and perhaps even chaotic. Since no model can be perfect, it becomes important to understand how forecasting can be improved, especially when training data is limited. An adverse event that can be readily studied in the laboratory is the occurrence of stick falls when humans attempt to balance a stick on their fingertips. Over the last 20 years, this task has been extensively investigated experimentally, and presently detailed mathematical models are available. LA - English DB - MTMT ER - TY - JOUR AU - Balogh, Tamás AU - Kovács, Balázs András AU - Insperger, Tamás TI - Human performance in virtual stabilization of a fractional-order system with reaction delay JF - JOURNAL OF THE ROYAL SOCIETY INTERFACE J2 - J R SOC INTERFACE VL - 21 PY - 2024 IS - 215 PG - 13 SN - 1742-5689 DO - 10.1098/rsif.2023.0685 UR - https://m2.mtmt.hu/api/publication/35085873 ID - 35085873 N1 - Funding text: The research reported in this article has been supported by the National Research, Development and Innovation Office (Grant no.NKFI-K138621), by the HUN-REN Hungarian Research Network and by Project no. TKP-9-8/PALY-2021, which has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-EGA funding scheme. AB - Virtual balancing tasks facilitate the study of human motion control: human reaction to the change of artificially introduced parameters can be studied in a computer environment. In this article, the dynamics of human stick balancing are generalized using fractional-order derivatives. Reaction delay sets a strong limitation on the length of the shortest stick that human subjects can balance. Human processing of visual input also exhibits a memory effect, which can be modelled by fractional-order derivatives. Therefore, we hypothesize a delayed fractional-order PD control of the unstable fractional-order process. The resulting equation of motion is investigated in a dimensionless framework, and stabilizability limits are determined as a function of the dynamics's order. These theoretical limits are then compared with the results of a systematic series of virtual balancing tests performed by 18 subjects. The comparison shows that the theoretical stabilizability limits for controllers with fixed fractional order correspond to the measured data points. The best fit is obtained if the fractional order of the underlying control law is 0.475. LA - English DB - MTMT ER - TY - CHAP AU - Trabelsi, Karim L. AU - Boussaada, Islam AU - Benarab, Amina AU - Molnár, Csenge Andrea AU - Niculescu, Silviu-Iulian AU - Insperger, Tamás ED - Kaïs, Ammari ED - Anna, Doubova ED - Stéphane, Gerbi ED - Manuel, González-Burgos TI - Central Nervous System Action on Rolling Balance Board Robust Stabilization: Computer Algebra and MID-Based Feedback Design T2 - Advances in Partial Differential Equations and Control VL - Part F3233 PB - Birkhäuser Publishing Ltd. CY - Cham SN - 9783031622649 T3 - Trends in Mathematics, ISSN 2297-0215 ; Part F3233. PY - 2024 SP - 215 EP - 247 PG - 33 DO - 10.1007/978-3-031-62265-6_11 UR - https://m2.mtmt.hu/api/publication/35232911 ID - 35232911 AB - Using the computer algebra system Maple, we consider the stabilization of a rolling balance board by means of the multiplicity-induced-dominancy (MID) property. The human stance on a rolling balance board is analyzed in the sagittal plane through a 2-degree-of-freedom mechanical model. Namely, the human body is modeled by a double-inverted pendulum which connects to the balance board through the ankle joint. The system is stabilized by the ankle torque managed by the central nervous system (CNS). The action of the CNS is modeled by a delayed full state feedback: A pointwise delay stands for all latencies in the neuromechanical system (reaction time, neuromechanical lag, etc.). The aim of the chapter is to achieve a good occurrence in terms of the decay rate, and it exhibits the links between multiple spectral values satisfying the MID property and the exponential stability property of the solution (Note that a preliminary version of this work was published in Benarab et al. (Rolling balance board robust stabilization: A MID-based design, in TDS 2022 - 17th IFAC Workshop on Time Delay Systems, Montreal, 2022).). © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024. LA - English DB - MTMT ER - TY - CONF AU - Szalai, Péter AU - Insperger, Tamás AU - Antali, Máté ED - Metrikine, Andrei ED - Alijani, Farbod TI - Nonlinear effects in the act-and-wait control of a linear DC actuator T2 - Online Book of Abstracts of the 11th European Nonlinear Dynamics Conference (ENOC 2024) PY - 2024 UR - https://m2.mtmt.hu/api/publication/35584936 ID - 35584936 LA - English DB - MTMT ER - TY - CHAP AU - Insperger, Tamás AU - Stépán, Gábor AU - Milton, J. ED - Breda, Dimitri TI - Dynamics of Human Balancing T2 - Controlling Delayed Dynamics VL - 604 PB - Springer Science+Business Media CY - Cham SN - 9783031011290 T3 - CISM Courses and Lectures, ISSN 0254-1971 ; 604. T3 - CISM Courses and Lectures, ISSN 0254-1971 ; 604. PY - 2023 SP - 343 EP - 364 PG - 22 DO - 10.1007/978-3-031-01129-0_11 UR - https://m2.mtmt.hu/api/publication/33151750 ID - 33151750 LA - English DB - MTMT ER - TY - CHAP AU - Insperger, Tamás AU - Stépán, Gábor ED - Breda, Dimitri TI - Regenerative Machine Tool Vibrations T2 - Controlling Delayed Dynamics VL - 604 PB - Springer Science+Business Media CY - Cham SN - 9783031011290 T3 - CISM Courses and Lectures, ISSN 0254-1971 ; 604. T3 - CISM Courses and Lectures, ISSN 0254-1971 ; 604. PY - 2023 SP - 311 EP - 341 PG - 31 DO - 10.1007/978-3-031-01129-0_10 UR - https://m2.mtmt.hu/api/publication/33151752 ID - 33151752 LA - English DB - MTMT ER -