The paper investigates the nonlinear dynamics of the collocated position control of a trolley that carries a pendulum. Delayed proportional derivative control force is considered, which is based on the position and velocity of the trolley only. Stability charts are constructed for different parameter combinations, which show intricate structures in the plane of the control parameters. To examine the nonlinear behaviour of the system, the Hopf bifurcation calculation is carried out after an infinite dimensional center manifold reduction. This indicates that supercritical Hopf bifurcations always exist at the boundary of the first stable lobe, however, for increasing time delays, the reappearing stable lobes may be bounded with subcritical Hopf bifurcations as well, and even quasi-periodic oscillations may occur.
{"title":"Nonlinear Oscillations in Delayed Collocated Control of Pendulum on Trolley","authors":"Bence Szaksz, G. Stépán","doi":"10.1115/detc2022-89838","DOIUrl":"https://doi.org/10.1115/detc2022-89838","url":null,"abstract":"\u0000 The paper investigates the nonlinear dynamics of the collocated position control of a trolley that carries a pendulum. Delayed proportional derivative control force is considered, which is based on the position and velocity of the trolley only. Stability charts are constructed for different parameter combinations, which show intricate structures in the plane of the control parameters. To examine the nonlinear behaviour of the system, the Hopf bifurcation calculation is carried out after an infinite dimensional center manifold reduction. This indicates that supercritical Hopf bifurcations always exist at the boundary of the first stable lobe, however, for increasing time delays, the reappearing stable lobes may be bounded with subcritical Hopf bifurcations as well, and even quasi-periodic oscillations may occur.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"178 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114091023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The utilization of mechanical-bearing-based precision motion stages (MBMS) is prevalent in the advanced manufacturing industries. However, the productivity of the MBMS is plagued by friction-induced vibrations, which can be controlled to a certain extent using a friction isolator. Earlier works investigating the dynamics of MBMS with a friction isolator considered a linear friction isolator, and the source of nonlinearity in the system was realized through the friction model only. In this work, we present the nonlinear analysis of the MBMS with a nonlinear friction isolator for the first time. We consider a two-degree-of-freedom spring-mass-damper system to model the servo-controlled motion stage with a nonlinear friction isolator. The characteristic of the dynamical friction in the system is captured using the Lu-Gre friction model. The system’s stability and nonlinear analysis are carried out using analytical methods. More specifically, the method of multiple scales is used to determine the nature of Hopf bifurcation on the stability lobe. The analytical results indicate the existence of subcritical and supercritical Hopf bifurcations in the system, which are later validated through numerical bifurcation. This observation implies that the nonlinearity in the system can be stabilizing or destabilizing in nature, depending on the choice of operating parameters.
{"title":"Bifurcation Analysis of a PD Controlled Motion Stage With a Nonlinear Friction Isolator","authors":"Ehab E. Basta, S. K. Gupta, O. Barry","doi":"10.1115/detc2022-91125","DOIUrl":"https://doi.org/10.1115/detc2022-91125","url":null,"abstract":"\u0000 The utilization of mechanical-bearing-based precision motion stages (MBMS) is prevalent in the advanced manufacturing industries. However, the productivity of the MBMS is plagued by friction-induced vibrations, which can be controlled to a certain extent using a friction isolator. Earlier works investigating the dynamics of MBMS with a friction isolator considered a linear friction isolator, and the source of nonlinearity in the system was realized through the friction model only. In this work, we present the nonlinear analysis of the MBMS with a nonlinear friction isolator for the first time. We consider a two-degree-of-freedom spring-mass-damper system to model the servo-controlled motion stage with a nonlinear friction isolator. The characteristic of the dynamical friction in the system is captured using the Lu-Gre friction model. The system’s stability and nonlinear analysis are carried out using analytical methods. More specifically, the method of multiple scales is used to determine the nature of Hopf bifurcation on the stability lobe. The analytical results indicate the existence of subcritical and supercritical Hopf bifurcations in the system, which are later validated through numerical bifurcation. This observation implies that the nonlinearity in the system can be stabilizing or destabilizing in nature, depending on the choice of operating parameters.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133960514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the stability of robots in machining. The goal is to improve the dynamic performance of robots using an additional acceleration signal fed back through the conventional built-in proportional-derivative controller provided by the manufacturer. The structure of the robot is modelled with a simple one degree-of-freedom lumped model. The control signals are fed back via a linear spring and damping. The time delays of feedback controllers are considered as zero-order holds, which results in sawtooth-like time-periodic time delays. The resulting equation of motion is an advanced delay differential equation. The semidiscretization method is shown for such systems with multiple sampled digital delays. First, we establish the stable regions in the plane of the sampling delay and the gain of the acceleration signal without machining. Then we show the possibility to improve stability in the simplest possible cutting case using the additional acceleration feedback controller compared to the cases without any controller or using only the proportional-derivative controller.
{"title":"Stability Analysis of a One Degree-of-Freedom Robot Model With Sampled Digital Acceleration Feedback Controller in Turning","authors":"Andras Bartfai, A. Barrios, Z. Dombovari","doi":"10.1115/detc2022-90937","DOIUrl":"https://doi.org/10.1115/detc2022-90937","url":null,"abstract":"\u0000 This study investigates the stability of robots in machining. The goal is to improve the dynamic performance of robots using an additional acceleration signal fed back through the conventional built-in proportional-derivative controller provided by the manufacturer. The structure of the robot is modelled with a simple one degree-of-freedom lumped model. The control signals are fed back via a linear spring and damping. The time delays of feedback controllers are considered as zero-order holds, which results in sawtooth-like time-periodic time delays. The resulting equation of motion is an advanced delay differential equation. The semidiscretization method is shown for such systems with multiple sampled digital delays. First, we establish the stable regions in the plane of the sampling delay and the gain of the acceleration signal without machining. Then we show the possibility to improve stability in the simplest possible cutting case using the additional acceleration feedback controller compared to the cases without any controller or using only the proportional-derivative controller.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117048701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an automatic procedure to enhance the accuracy of the numerical solution of an optimal control problem (OCP) discretized via direct collocation at Gauss-Legendre points. First, a numerical solution is obtained by solving a nonlinear program (NLP). Then, the method evaluates its accuracy and adaptively changes both the degree of the approximating polynomial within each mesh interval and the number of mesh intervals until a prescribed accuracy is met. The number of mesh intervals is increased for all state vector components alike, in a classical fashion. Instead, improving on state-of-the-art procedures, the degrees of the polynomials approximating the different components of the state vector are allowed to assume, in each finite element, distinct values. This explains the pnh definition, where n is the state dimension. Instead, in the literature, the degree is always raised to the highest order for all the state components, with a clear waste of resources. Numerical tests on three OCP problems highlight that, under the same maximum allowable error, by independently selecting the degree of the polynomial for each state, our method effectively picks lower degrees for some of the states, thus reducing the overall number of variables in the NLP. Accordingly, various advantages are brought about, the most remarkable being: (i) an increased computational efficiency for the final enhanced mesh with solution accuracy still within the specified tolerance, (ii) a reduced risk of being trapped by local minima due to the reduced NLP size.
{"title":"A pnh-Adaptive Refinement Procedure for Numerical Optimal Control Problems","authors":"L. Bartali, M. Gabiccini, M. Guiggiani","doi":"10.1115/detc2022-89376","DOIUrl":"https://doi.org/10.1115/detc2022-89376","url":null,"abstract":"\u0000 This paper presents an automatic procedure to enhance the accuracy of the numerical solution of an optimal control problem (OCP) discretized via direct collocation at Gauss-Legendre points. First, a numerical solution is obtained by solving a nonlinear program (NLP). Then, the method evaluates its accuracy and adaptively changes both the degree of the approximating polynomial within each mesh interval and the number of mesh intervals until a prescribed accuracy is met. The number of mesh intervals is increased for all state vector components alike, in a classical fashion. Instead, improving on state-of-the-art procedures, the degrees of the polynomials approximating the different components of the state vector are allowed to assume, in each finite element, distinct values. This explains the pnh definition, where n is the state dimension. Instead, in the literature, the degree is always raised to the highest order for all the state components, with a clear waste of resources.\u0000 Numerical tests on three OCP problems highlight that, under the same maximum allowable error, by independently selecting the degree of the polynomial for each state, our method effectively picks lower degrees for some of the states, thus reducing the overall number of variables in the NLP. Accordingly, various advantages are brought about, the most remarkable being: (i) an increased computational efficiency for the final enhanced mesh with solution accuracy still within the specified tolerance, (ii) a reduced risk of being trapped by local minima due to the reduced NLP size.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121633618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nonlinear energy sinks (NESs) are strongly nonlinear mechanical oscillators that are weakly coupled to a mechanical primary system. Through targeted energy transfer (TET), vibration energy is irreversibly transferred from the primary system to the NES, making the NES an attractive passive vibration control device. Furthermore, because of the NES’ strong nonlinearity, the NES has a variable natural frequency, unlike linear vibration control devices. This enables a self-tuning property where the NES adapts to the primary system’s vibration frequency, making the NES a broadband vibration absorber. This self-tuning extends to multi-frequency vibrations through resonance capture cascade (RCC), where the NES tunes itself to the different frequencies in sequential order. Recently, some works have discussed the piezoelectric NES, a nonlinear electrical circuit that interfaces with a mechanical system through a piezoelectric transducer. This paper will show for the first time that by using an electromagnetic transducer instead of a piezoelectrical transducer, an electromagnetic NES is obtained. Furthermore, this work will show that dynamics of mechanical, piezoelectric and electromagnetic NESs can be generalized under a universal NES in a slow flow expression and that resonance capture cascade occurs for all the NES types. The performance of the NES configurations are compared and their physical components are discussed.
{"title":"Nonlinear Energy Sink and Targeted Energy Transfer in Smart Structures","authors":"Kevin Dekemele, P. Van Torre, M. Loccufier","doi":"10.1115/detc2022-89608","DOIUrl":"https://doi.org/10.1115/detc2022-89608","url":null,"abstract":"\u0000 Nonlinear energy sinks (NESs) are strongly nonlinear mechanical oscillators that are weakly coupled to a mechanical primary system. Through targeted energy transfer (TET), vibration energy is irreversibly transferred from the primary system to the NES, making the NES an attractive passive vibration control device. Furthermore, because of the NES’ strong nonlinearity, the NES has a variable natural frequency, unlike linear vibration control devices. This enables a self-tuning property where the NES adapts to the primary system’s vibration frequency, making the NES a broadband vibration absorber. This self-tuning extends to multi-frequency vibrations through resonance capture cascade (RCC), where the NES tunes itself to the different frequencies in sequential order. Recently, some works have discussed the piezoelectric NES, a nonlinear electrical circuit that interfaces with a mechanical system through a piezoelectric transducer. This paper will show for the first time that by using an electromagnetic transducer instead of a piezoelectrical transducer, an electromagnetic NES is obtained. Furthermore, this work will show that dynamics of mechanical, piezoelectric and electromagnetic NESs can be generalized under a universal NES in a slow flow expression and that resonance capture cascade occurs for all the NES types. The performance of the NES configurations are compared and their physical components are discussed.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127385343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
People with neuromuscular deficits may show balance issues that put them in a higher risk of fall as compared to healthy people. To reduce the risk of fall, balance-board (BB)-based rehabilitation intervention has been widely used. However, despite the extensive use of BB-based interventions, the mechanisms responsible for rehabilitation remain unclear. To better understand these mechanisms, several studies have used a system dynamics approach to investigate the effect of neuromuscular deficits (visual, vestibular, proprioceptive) and sensorimotor latencies on the stability and dynamical behavior of the human-BB system. Though, to the best knowledge of the authors, the effect of the BB mass on the stability and dynamics of the human-BB system has never been investigated. In the present study, bifurcation analyses, root finding techniques, and computational simulations are used to investigate the effect of the BB mass and BB time-delay on the stability, equilibrium, and robustness of the human-BB upright posture (UP) for cases where either proprioceptive or visual and vestibular deficits are considered. The results show that the BB mass and BB time-delay play a critical role on the UP stability, leaning postures, and robustness of the human-BB system. In fact, increasing BB mass reduces the range of neuromuscular gains that stabilize the system and shrinks the basin of attraction of the UP, which is related to the human-BB system’s robustness to posture disturbances. This effect is more evident in the case where visual and vestibular deficits are considered in simulation. This relationship may have implications on the design and development of BBs with tunable mass and tunable time-delay. The BB could be designed to tune time-delay and mass, so patients could be better challenged during BB-based intervention in a more patient-specific manner.
{"title":"The Effect of the Balance Board Mass on the Stability, Equilibrium, and Robustness of the Human-Balance Board System","authors":"Erik Chumacero, Jie Yang","doi":"10.1115/detc2022-90628","DOIUrl":"https://doi.org/10.1115/detc2022-90628","url":null,"abstract":"\u0000 People with neuromuscular deficits may show balance issues that put them in a higher risk of fall as compared to healthy people. To reduce the risk of fall, balance-board (BB)-based rehabilitation intervention has been widely used. However, despite the extensive use of BB-based interventions, the mechanisms responsible for rehabilitation remain unclear. To better understand these mechanisms, several studies have used a system dynamics approach to investigate the effect of neuromuscular deficits (visual, vestibular, proprioceptive) and sensorimotor latencies on the stability and dynamical behavior of the human-BB system. Though, to the best knowledge of the authors, the effect of the BB mass on the stability and dynamics of the human-BB system has never been investigated. In the present study, bifurcation analyses, root finding techniques, and computational simulations are used to investigate the effect of the BB mass and BB time-delay on the stability, equilibrium, and robustness of the human-BB upright posture (UP) for cases where either proprioceptive or visual and vestibular deficits are considered. The results show that the BB mass and BB time-delay play a critical role on the UP stability, leaning postures, and robustness of the human-BB system. In fact, increasing BB mass reduces the range of neuromuscular gains that stabilize the system and shrinks the basin of attraction of the UP, which is related to the human-BB system’s robustness to posture disturbances. This effect is more evident in the case where visual and vestibular deficits are considered in simulation. This relationship may have implications on the design and development of BBs with tunable mass and tunable time-delay. The BB could be designed to tune time-delay and mass, so patients could be better challenged during BB-based intervention in a more patient-specific manner.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"2005 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128305704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, Super-Coiled Polymer (SCP) actuators have been investigated as a potential high yield and minimal cost alternative to bulky, power hungry and expensive conventional actuators. A major challenge however, has been finding appropriate general and industry uses for these actuators due to their nonlinear hysteretic response. This paper seeks to compare the hysteretic response for SCP actuators based on different thread weights and sizes and thus suggest possible directions for their use. The actuators were produced through coiling and heat treatment actuated via Arduino code and a microcontroller circuit. The hysteresis properties were obtained experimentally by supplying a controlled voltage to the system. The response was recorded via a camera and was then processed using MATLAB; the resulting displacement and strain were used to observe the hysteretic characteristics. These characteristics were used as the basis for recommending different applications for these SCP actuators. The results show single ply supercoiled polymers may be used in sensitive low stress applications, the triple ply and greater number of plies used in high stress applications, and the double ply used in applications that are sensitive but also have moderate stress requirements. It is recommended that this research into SCP actuators be furthered by developing hysteresis models for compensation, control and exploring their use in robotic systems and tactile mechanisms.
{"title":"Comparison of the Hysteresis Response of Super-Coiled Polymer (SCP) Actuators","authors":"J. H. Henry, J. Bridge","doi":"10.1115/detc2022-90107","DOIUrl":"https://doi.org/10.1115/detc2022-90107","url":null,"abstract":"\u0000 In recent years, Super-Coiled Polymer (SCP) actuators have been investigated as a potential high yield and minimal cost alternative to bulky, power hungry and expensive conventional actuators. A major challenge however, has been finding appropriate general and industry uses for these actuators due to their nonlinear hysteretic response. This paper seeks to compare the hysteretic response for SCP actuators based on different thread weights and sizes and thus suggest possible directions for their use.\u0000 The actuators were produced through coiling and heat treatment actuated via Arduino code and a microcontroller circuit. The hysteresis properties were obtained experimentally by supplying a controlled voltage to the system. The response was recorded via a camera and was then processed using MATLAB; the resulting displacement and strain were used to observe the hysteretic characteristics.\u0000 These characteristics were used as the basis for recommending different applications for these SCP actuators. The results show single ply supercoiled polymers may be used in sensitive low stress applications, the triple ply and greater number of plies used in high stress applications, and the double ply used in applications that are sensitive but also have moderate stress requirements.\u0000 It is recommended that this research into SCP actuators be furthered by developing hysteresis models for compensation, control and exploring their use in robotic systems and tactile mechanisms.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121114434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of impact coefficient of restitution on the nonlinear response of the follower is investigated at different follower guides’ clearances, different cam speeds and different followers’ offsets. The impact between the cam and the follower and between the follower and its guides are considered in the presence of coefficient of restitution and follower offset. The chaotic phenomenon of the follower due to the impact coefficient of restitution is detected by using phase-plane diagram. The numerical simulation of the nonlinear response of the follower is simulated using SolidWorks program. The chaotic phenomenon in cam follower system is increased with the increasing of impact coefficient of restitution value in which the potential energy of the follower has been decreased in the presence of follower offset. The chaotic motion of the follower response is occurred due to the increase in cam speeds, follower’s offsets, follower guides’ clearances and impact coefficient of restitution.
{"title":"Effect of the Impact Coefficient of Restitution on the Nonlinear Dynamics Phenomenon of Flat-Faced Follower With Polydyne Cam Mechanism With Clearance","authors":"L. S. Yousuf","doi":"10.1115/detc2022-89430","DOIUrl":"https://doi.org/10.1115/detc2022-89430","url":null,"abstract":"\u0000 The effect of impact coefficient of restitution on the nonlinear response of the follower is investigated at different follower guides’ clearances, different cam speeds and different followers’ offsets. The impact between the cam and the follower and between the follower and its guides are considered in the presence of coefficient of restitution and follower offset. The chaotic phenomenon of the follower due to the impact coefficient of restitution is detected by using phase-plane diagram. The numerical simulation of the nonlinear response of the follower is simulated using SolidWorks program. The chaotic phenomenon in cam follower system is increased with the increasing of impact coefficient of restitution value in which the potential energy of the follower has been decreased in the presence of follower offset. The chaotic motion of the follower response is occurred due to the increase in cam speeds, follower’s offsets, follower guides’ clearances and impact coefficient of restitution.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114476001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work presents a numerical validation and capability demonstration of the solver MBDyn when applied to a complex tiltrotor model. The Bell XV-15 tiltrotor equipped with Advanced Technology Blades (ATB) is chosen since a considerable amount of data is publicly available. The multibody modeling of each sub-component, i.e. the rotor, blades, yoke, drive system, and the airframe is illustrated and validated considering experimental and numerical results. This work is a first step towards further, more complex analyses, such as whirl-flutter stability assessment, transient maneuvers, and pilot-vehicle interaction.
{"title":"Flexible Multibody Model of a Complete Tiltrotor for Aeroservoelastic Analysis","authors":"A. Cocco, Alberto Savino, P. Masarati","doi":"10.1115/detc2022-89734","DOIUrl":"https://doi.org/10.1115/detc2022-89734","url":null,"abstract":"\u0000 This work presents a numerical validation and capability demonstration of the solver MBDyn when applied to a complex tiltrotor model. The Bell XV-15 tiltrotor equipped with Advanced Technology Blades (ATB) is chosen since a considerable amount of data is publicly available. The multibody modeling of each sub-component, i.e. the rotor, blades, yoke, drive system, and the airframe is illustrated and validated considering experimental and numerical results. This work is a first step towards further, more complex analyses, such as whirl-flutter stability assessment, transient maneuvers, and pilot-vehicle interaction.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130034664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Usage of contact mechanics methodologies is a pervasive modeling requirement in dynamic simulations. While for some trivial problems, solutions taken from analytical geometry are available, use of a finite element framework is common to achieve formulation generality. This work explores two dynamic contact formulations: one based on the traditional node-to-segment (NTS) approach, and a variationally consistent segment-to-segment (STS) mortar formulation. The NTS formulation employed here enforces the constraints kinematically (i.e., the interpenetration is enforced to the solver tolerance), whereas the mortar approach uses Lagrange multipliers to enforce the contact constraints. Both approaches are implemented in the open-source finite element framework Multiphysics Object-Oriented Simulation Environment (MOOSE). The results highlight two relevant contact-interface-related dynamic phenomena in finite element simulations. First, stabilization of contact constraints is discussed, taking into account the evolution of the total energy in a benchmark problem. Second, the influence of finite element discretization on both of the aforementioned contact formulations is analyzed by exercising a large-deformation example with continuous relative sliding. Variationally consistent contact approaches such as the mortar formulation lead to improved energy preservation and avoid spurious excitation of the system’s frequencies. This is especially relevant in settings where inertia and vibrations are of importance.
{"title":"On Practical Aspects of Variational Consistency in Contact Dynamics","authors":"A. Recuero, A. Lindsay","doi":"10.1115/detc2022-89152","DOIUrl":"https://doi.org/10.1115/detc2022-89152","url":null,"abstract":"\u0000 Usage of contact mechanics methodologies is a pervasive modeling requirement in dynamic simulations. While for some trivial problems, solutions taken from analytical geometry are available, use of a finite element framework is common to achieve formulation generality. This work explores two dynamic contact formulations: one based on the traditional node-to-segment (NTS) approach, and a variationally consistent segment-to-segment (STS) mortar formulation. The NTS formulation employed here enforces the constraints kinematically (i.e., the interpenetration is enforced to the solver tolerance), whereas the mortar approach uses Lagrange multipliers to enforce the contact constraints. Both approaches are implemented in the open-source finite element framework Multiphysics Object-Oriented Simulation Environment (MOOSE). The results highlight two relevant contact-interface-related dynamic phenomena in finite element simulations. First, stabilization of contact constraints is discussed, taking into account the evolution of the total energy in a benchmark problem. Second, the influence of finite element discretization on both of the aforementioned contact formulations is analyzed by exercising a large-deformation example with continuous relative sliding. Variationally consistent contact approaches such as the mortar formulation lead to improved energy preservation and avoid spurious excitation of the system’s frequencies. This is especially relevant in settings where inertia and vibrations are of importance.","PeriodicalId":193710,"journal":{"name":"Volume 9: 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122932236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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