Wang Jun, Zi-Jian Yang, Yun-Hao Zhang, Jian-Chao Zhang
Nonlinear energy sinks (NES) are highly efficient vibration energy absorption and dissipation devices, and play an important vibration-suppression role in many types of structures. In this study, the influence of parameters on the combined stiffness nonlinear energy sink system is revealed from the perspective of energy, in which combined-stiffness terms are composed of piecewise linear stiffness and cubic stiffness. First, the slow-varying derivative of the combined-stiffness nonlinear energy sink system is calculated based on the complexification-averaging and multiscale methods. Second, an approximate expression for the extreme points on the slow-invariant manifold (SIM) of the system is derived by polynomial approximation, and the energy dissipation equation of the combined-stiffness nonlinear energy sink system is derived. The impacts of the stiffness gap, piecewise linear stiffness coefficient, and cubic stiffness coefficient on the system are analyzed by studying the energy transfer efficiency equation. Additionally, the relationship between the damping ratio of the primary structure and the dissipation time is analyzed.
{"title":"Energy Transfer and Dissipation in Combined-Stiffness Nonlinear Energy Sink Systems","authors":"Wang Jun, Zi-Jian Yang, Yun-Hao Zhang, Jian-Chao Zhang","doi":"10.1115/1.4064271","DOIUrl":"https://doi.org/10.1115/1.4064271","url":null,"abstract":"Nonlinear energy sinks (NES) are highly efficient vibration energy absorption and dissipation devices, and play an important vibration-suppression role in many types of structures. In this study, the influence of parameters on the combined stiffness nonlinear energy sink system is revealed from the perspective of energy, in which combined-stiffness terms are composed of piecewise linear stiffness and cubic stiffness. First, the slow-varying derivative of the combined-stiffness nonlinear energy sink system is calculated based on the complexification-averaging and multiscale methods. Second, an approximate expression for the extreme points on the slow-invariant manifold (SIM) of the system is derived by polynomial approximation, and the energy dissipation equation of the combined-stiffness nonlinear energy sink system is derived. The impacts of the stiffness gap, piecewise linear stiffness coefficient, and cubic stiffness coefficient on the system are analyzed by studying the energy transfer efficiency equation. Additionally, the relationship between the damping ratio of the primary structure and the dissipation time is analyzed.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"20 49","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139156153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper elaborates on various synchronization aspects for nonlinear systems belonging to a specific class, under different scenarios. The method proposed in the article refers to the Lyapunov direct method and Extended Kalman Filter technique to ensure the convergence of the slave state trajectories to the corresponding master state trajectories. Initially, an output feedback-based synchronization approach is attempted, assuming that bounds of unmeasurable states are available for controller synthesis. However, this approach has limitations in handling complete parametric uncertainty for the considered class of systems. To overcome this limitation, a state feedback-based synchronization scheme is presented, and an appropriate state feedback controller and parametric adaptation laws are designed analytically. In the case where only output states are accessible for feedback, and the system is subjected to complete parametric uncertainty, an Extended Kalman Filter based estimation scheme is used. This approach facilitates achieving synchronization despite the presence of external channel noise disturbances with a Gaussian distribution. The potency of the proposed results is successfully substantiated for the chaotic Lorenz system, which belongs to the considered class of nonlinear systems. Ultimately, numerical simulations are provided to corroborate the efficacy of proposed synchronization and estimation strategy.
{"title":"Synchronization of a Class of Nonlinear Systems With and Without Uncertainty Using State Feedback and Extended Kalman Filter Based Control Scheme","authors":"R. K. Ranjan, Bharat Bhushan Sharma","doi":"10.1115/1.4064270","DOIUrl":"https://doi.org/10.1115/1.4064270","url":null,"abstract":"\u0000 The paper elaborates on various synchronization aspects for nonlinear systems belonging to a specific class, under different scenarios. The method proposed in the article refers to the Lyapunov direct method and Extended Kalman Filter technique to ensure the convergence of the slave state trajectories to the corresponding master state trajectories. Initially, an output feedback-based synchronization approach is attempted, assuming that bounds of unmeasurable states are available for controller synthesis. However, this approach has limitations in handling complete parametric uncertainty for the considered class of systems. To overcome this limitation, a state feedback-based synchronization scheme is presented, and an appropriate state feedback controller and parametric adaptation laws are designed analytically. In the case where only output states are accessible for feedback, and the system is subjected to complete parametric uncertainty, an Extended Kalman Filter based estimation scheme is used. This approach facilitates achieving synchronization despite the presence of external channel noise disturbances with a Gaussian distribution. The potency of the proposed results is successfully substantiated for the chaotic Lorenz system, which belongs to the considered class of nonlinear systems. Ultimately, numerical simulations are provided to corroborate the efficacy of proposed synchronization and estimation strategy.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"49 30","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138946225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In view of the crucial importance of optimal control in many application areas and the improved performance of path-fitted variational integrators, the paper links these two aspects and presents a methodology to find optimal control policies for mechanical systems. The main process of the methodology is employing path-fitted variational integrators to discretize the forced mechanical equations and further taking the obtained discrete equations as equality constraints for the final optimization problem. Simultaneously, the discretization also provides a reasonable way to approximate the objective functional and incorporate the boundary conditions. With the transformation of optimal control problems into nonlinear optimization problems, all the benefits of path-fitted variational integrators are inherited by the presented methodology, mainly expressed in giving more faithful optimizations and thus more accurate solutions, providing greater possibility of global optimality, as well as conserving computed control efforts. These superiorities, verified by the optimal control of an overhead crane, indicate that the methodology has high potential application in industrial control field.
{"title":"Optimal Control of Mechanical Systems Based On Path-Fitted Variational Integrators","authors":"Xinlei Kong, Shiyu Yu, Huibin Wu","doi":"10.1115/1.4064360","DOIUrl":"https://doi.org/10.1115/1.4064360","url":null,"abstract":"\u0000 In view of the crucial importance of optimal control in many application areas and the improved performance of path-fitted variational integrators, the paper links these two aspects and presents a methodology to find optimal control policies for mechanical systems. The main process of the methodology is employing path-fitted variational integrators to discretize the forced mechanical equations and further taking the obtained discrete equations as equality constraints for the final optimization problem. Simultaneously, the discretization also provides a reasonable way to approximate the objective functional and incorporate the boundary conditions. With the transformation of optimal control problems into nonlinear optimization problems, all the benefits of path-fitted variational integrators are inherited by the presented methodology, mainly expressed in giving more faithful optimizations and thus more accurate solutions, providing greater possibility of global optimality, as well as conserving computed control efforts. These superiorities, verified by the optimal control of an overhead crane, indicate that the methodology has high potential application in industrial control field.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"35 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138950056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sankalp Tiwari, Junaidvali Shaik, C. P. Vyasarayani
Delay differential equations (DDEs) appear in many applications, and determining their stability is a challenging task that has received considerable attention. Numerous methods for stability determination of a given DDE exist in the literature. However, in practical scenarios it may be beneficial to be able to determine the stability of a delayed system based solely on its response to given inputs, without the need to consider the underlying governing DDE. In this work we propose such a data-driven method, assuming only three things about the underlying DDE: (i) it is linear, (ii) its coefficients are either constant or time-periodic with a known fundamental period, and (iii) the largest delay is known. Our approach involves giving the first few functions of an orthonormal polynomial basis as input, and measuring/computing the corresponding responses to generate a state transition matrix M, whose largest eigenvalue determines the stability. We demonstrate the correctness, efficacy and convergence of our method by studying four candidate DDEs with differing features. We show that our approach is robust to noise, thereby establishing its suitability for practical applications, wherein measurement errors are unavoidable.
{"title":"Data Driven Approach to Determine Linear Stability of Delay Differential Equations Using Orthonormal History Functions","authors":"Sankalp Tiwari, Junaidvali Shaik, C. P. Vyasarayani","doi":"10.1115/1.4064251","DOIUrl":"https://doi.org/10.1115/1.4064251","url":null,"abstract":"\u0000 Delay differential equations (DDEs) appear in many applications, and determining their stability is a challenging task that has received considerable attention. Numerous methods for stability determination of a given DDE exist in the literature. However, in practical scenarios it may be beneficial to be able to determine the stability of a delayed system based solely on its response to given inputs, without the need to consider the underlying governing DDE. In this work we propose such a data-driven method, assuming only three things about the underlying DDE: (i) it is linear, (ii) its coefficients are either constant or time-periodic with a known fundamental period, and (iii) the largest delay is known. Our approach involves giving the first few functions of an orthonormal polynomial basis as input, and measuring/computing the corresponding responses to generate a state transition matrix M, whose largest eigenvalue determines the stability. We demonstrate the correctness, efficacy and convergence of our method by studying four candidate DDEs with differing features. We show that our approach is robust to noise, thereby establishing its suitability for practical applications, wherein measurement errors are unavoidable.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"5 3","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Motor bearing is the key vulnerable part of the servo motor in an industrial robot, which is always arranged at the joint that is the main load area. In the movement process of the robot, motor bearing bears a great impact due to the frequent movement of joints, which is easily damaged. The fault characteristic information of a bearing in these complex conditions shows strong non-stationary features. Early non-stationary fault signals are often weak and submerged in background noise. The non-stationary signal processing method using computed order analysis and the weak signal enhancement method using adaptive stochastic resonance both show good performances for the above problems. Inspired by these, a hybrid diagnosis strategy for motor bearing under these speed conditions is proposed. Firstly, the non-stationary fault signals of the motor bearing are transformed into stationary angular signals via computed order analysis. Then, the fault modes are identified via resonance demodulation and variational mode decomposition in the order spectrum. Finally, adaptive stochastic resonance is used to extract the fault features reflecting the bearing operation state. Two types of typical speed conditions are considered, which is representative at the joint. Numerical simulation analysis and experiments verify the effectiveness of the diagnosis method.
{"title":"Motor Bearing Fault Diagnosis in an Industrial Robot Under Complex Variable Speed Conditions","authors":"Tao Gong, Zhongqiu Wang, Qiang Ma, Jianhua Yang","doi":"10.1115/1.4064250","DOIUrl":"https://doi.org/10.1115/1.4064250","url":null,"abstract":"\u0000 Motor bearing is the key vulnerable part of the servo motor in an industrial robot, which is always arranged at the joint that is the main load area. In the movement process of the robot, motor bearing bears a great impact due to the frequent movement of joints, which is easily damaged. The fault characteristic information of a bearing in these complex conditions shows strong non-stationary features. Early non-stationary fault signals are often weak and submerged in background noise. The non-stationary signal processing method using computed order analysis and the weak signal enhancement method using adaptive stochastic resonance both show good performances for the above problems. Inspired by these, a hybrid diagnosis strategy for motor bearing under these speed conditions is proposed. Firstly, the non-stationary fault signals of the motor bearing are transformed into stationary angular signals via computed order analysis. Then, the fault modes are identified via resonance demodulation and variational mode decomposition in the order spectrum. Finally, adaptive stochastic resonance is used to extract the fault features reflecting the bearing operation state. Two types of typical speed conditions are considered, which is representative at the joint. Numerical simulation analysis and experiments verify the effectiveness of the diagnosis method.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"3 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139006512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High accuracy numerical methods to solve the nonlinear Föppl-von Kármán (FvK) equations usually work well only in simple domains such as rectangular regions. Computational conformal geometry (CCG) provides a systematic method to transform complicated surfaces into simple domains, preserving the orthogonal frames, such that the corresponding FvK equations can be solved by more effective numerical methods. The conform map is calculated by solving a pair of Laplace equations on a fine Delauney triangular mesh of the surface, which is numerically robust, and the map is harmonic and subsequently C∞ smooth, such that all the evaluations and spatial derivatives required by high accuracy methods at the regular nodes can be accurately and efficiently calculated. A variational functional corresponding to the FvK equations is derived for shells, which enable the problem to be solved by the finite element methods and compared with the commercial software Abaqus; fewer degrees of freedom are required in solving the transverse displacements and Airy functions of the FvK equations. The effectiveness of the proposed approach is verified by several benchmark examples, and the current method is suitable to calculate the large deflections and nonlinear dynamical responses of plates/shallow shells with arbitrary shapes.
{"title":"A Computational Conformal Geometry Approach to Calculate the Large Deformations of Plates/shells with Arbitrary Shapes","authors":"Yipeng Liu, Wei Fan, Hui Ren","doi":"10.1115/1.4064252","DOIUrl":"https://doi.org/10.1115/1.4064252","url":null,"abstract":"\u0000 High accuracy numerical methods to solve the nonlinear Föppl-von Kármán (FvK) equations usually work well only in simple domains such as rectangular regions. Computational conformal geometry (CCG) provides a systematic method to transform complicated surfaces into simple domains, preserving the orthogonal frames, such that the corresponding FvK equations can be solved by more effective numerical methods. The conform map is calculated by solving a pair of Laplace equations on a fine Delauney triangular mesh of the surface, which is numerically robust, and the map is harmonic and subsequently C∞ smooth, such that all the evaluations and spatial derivatives required by high accuracy methods at the regular nodes can be accurately and efficiently calculated. A variational functional corresponding to the FvK equations is derived for shells, which enable the problem to be solved by the finite element methods and compared with the commercial software Abaqus; fewer degrees of freedom are required in solving the transverse displacements and Airy functions of the FvK equations. The effectiveness of the proposed approach is verified by several benchmark examples, and the current method is suitable to calculate the large deflections and nonlinear dynamical responses of plates/shallow shells with arbitrary shapes.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"30 11","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this theoretical study, a recently developed inerter-based pendulum vibration absorber (IPVA) coupled with energy harvesting capabilities is applied to the quarter car model with class C road conditions (ISO 8608). The impact of varying the pendulum length parameter on power harvesting, ride comfort (sprung mass acceleration), and road handling is investigated. It is discovered that P-bifurcation of the probability density function (PDF), can simultaneously occur with enhanced output power (40% improvements), low sprung mass acceleration (60% improvements), and better road handling (60% improvements) when compared with the linear benchmark system. To predict this bifurcation, a Wiener path integration (WPI) method coupled with curvature checking is developed for the PDF. An efficient bifurcation detection algorithm is developed which leads to the prediction of monomodal, bimodal, and rotation PDF regions in the noise intensity-electrical damping plane. Using Monte Carlo simulations (MCS), the performance metrics were then compared against the optimal linear benchmark for varying driving speed on a class F road while varying the electrical damping so that the system is at or near P-bifurcation. Energy transfer into the electrical domain and power harvested is shown to be up to 43% and 20% higher than for the optimized linear system, respectively. Electrical efficiency considerations show that generator selection is also a factor. Ride comfort and road handling still saw improvements of at least 59%. Finally, the new algorithm effectively reduces an exhaustive MCS for various parameter configurations when qualitative changes in the PDF are linked to performance.
{"title":"P-Bifurcation Analysis of a Quarter-Car Model with Inerter-based Pendulum Vibration Absorber: A Wiener Path Integration Approach","authors":"Joel A. Cosner, Wei-Che Tai","doi":"10.1115/1.4064202","DOIUrl":"https://doi.org/10.1115/1.4064202","url":null,"abstract":"\u0000 In this theoretical study, a recently developed inerter-based pendulum vibration absorber (IPVA) coupled with energy harvesting capabilities is applied to the quarter car model with class C road conditions (ISO 8608). The impact of varying the pendulum length parameter on power harvesting, ride comfort (sprung mass acceleration), and road handling is investigated. It is discovered that P-bifurcation of the probability density function (PDF), can simultaneously occur with enhanced output power (40% improvements), low sprung mass acceleration (60% improvements), and better road handling (60% improvements) when compared with the linear benchmark system. To predict this bifurcation, a Wiener path integration (WPI) method coupled with curvature checking is developed for the PDF. An efficient bifurcation detection algorithm is developed which leads to the prediction of monomodal, bimodal, and rotation PDF regions in the noise intensity-electrical damping plane. Using Monte Carlo simulations (MCS), the performance metrics were then compared against the optimal linear benchmark for varying driving speed on a class F road while varying the electrical damping so that the system is at or near P-bifurcation. Energy transfer into the electrical domain and power harvested is shown to be up to 43% and 20% higher than for the optimized linear system, respectively. Electrical efficiency considerations show that generator selection is also a factor. Ride comfort and road handling still saw improvements of at least 59%. Finally, the new algorithm effectively reduces an exhaustive MCS for various parameter configurations when qualitative changes in the PDF are linked to performance.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"19 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138590253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nonprehensile manipulation involves moving objects without physical grasping using methods such as rolling, sliding, pushing, and throwing. In the context of rolling manipulation, a novel non-conventional type manipulator, referred to as the ball-on-flexible beam system, is presented in this paper. A flexible beam with multiple linear actuating rods attached to the underside of it can be controlled to move an overlying ball using rolling manipulation. Since the absence of physical grasping in nonprehensile manipulation often requires taking into account the dynamics of the system, we focus on the derivation of the dynamic model of the ball-on-flexible beam in this paper. The dynamic model is derived using the Euler-Lagrangian formulation. In the calculation of the kinetic and potential energies of the beam and the ball, the deflection of the flexible beam is taken into account based on the Euler-Bernoulli beam theory. The accuracy of the derived model is verified through a finite element analysis (FEA) case study.
{"title":"Dynamic Modeling of the Ball-On-Flexible Beam Using Euler-Lagrangian Formulation","authors":"Du-Soon Choi, Seong Youb Chung, Ji-Chul Ryu","doi":"10.1115/1.4064199","DOIUrl":"https://doi.org/10.1115/1.4064199","url":null,"abstract":"\u0000 Nonprehensile manipulation involves moving objects without physical grasping using methods such as rolling, sliding, pushing, and throwing. In the context of rolling manipulation, a novel non-conventional type manipulator, referred to as the ball-on-flexible beam system, is presented in this paper. A flexible beam with multiple linear actuating rods attached to the underside of it can be controlled to move an overlying ball using rolling manipulation. Since the absence of physical grasping in nonprehensile manipulation often requires taking into account the dynamics of the system, we focus on the derivation of the dynamic model of the ball-on-flexible beam in this paper. The dynamic model is derived using the Euler-Lagrangian formulation. In the calculation of the kinetic and potential energies of the beam and the ball, the deflection of the flexible beam is taken into account based on the Euler-Bernoulli beam theory. The accuracy of the derived model is verified through a finite element analysis (FEA) case study.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"19 18","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138591259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present paper proposes a neural network-based adaptive region-tracking control strategy for a flexible-joint robot manipulator subjected to region constraints. The developed neural network-based control strategy is able to globally stabilize the robot manipulator and cope with model uncertainties and the external unknown bounded disturbances. Different from the existing literature, by using the sliding mode technology and the singular perturbation theory, the developed control strategy does not require the high-order derivatives of the link states such as jerk and acceleration since the high-order derivative information is not always available in practical applications. By using Lyapunov stability theory, it is proved that the proposed neural network-based control strategy can guarantee that all the parameter variables in the closed-loop system are bounded, and the flexible-joint robot manipulator with unknown dynamics can reach inside the dynamic region and also maintain the velocity matching with the desired moving region. Since the assumption of linearization of the unknown dynamic parameters is removed, the proposed control strategy does not require the calculation of the complex regression matrix. Therefore, the proposed method has great robustness and the ability of model generalization. Simulations are given to demonstrate the validity of the proposed control strategy.
{"title":"Neural Network-Based Region Tracking Control for a Flexible-Joint Robot Manipulator","authors":"Jinwei Yu, Mengyang Wu, Jinchen Ji, Weihua Yang","doi":"10.1115/1.4064201","DOIUrl":"https://doi.org/10.1115/1.4064201","url":null,"abstract":"\u0000 The present paper proposes a neural network-based adaptive region-tracking control strategy for a flexible-joint robot manipulator subjected to region constraints. The developed neural network-based control strategy is able to globally stabilize the robot manipulator and cope with model uncertainties and the external unknown bounded disturbances. Different from the existing literature, by using the sliding mode technology and the singular perturbation theory, the developed control strategy does not require the high-order derivatives of the link states such as jerk and acceleration since the high-order derivative information is not always available in practical applications. By using Lyapunov stability theory, it is proved that the proposed neural network-based control strategy can guarantee that all the parameter variables in the closed-loop system are bounded, and the flexible-joint robot manipulator with unknown dynamics can reach inside the dynamic region and also maintain the velocity matching with the desired moving region. Since the assumption of linearization of the unknown dynamic parameters is removed, the proposed control strategy does not require the calculation of the complex regression matrix. Therefore, the proposed method has great robustness and the ability of model generalization. Simulations are given to demonstrate the validity of the proposed control strategy.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"17 26","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138591570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shenggang Du, Yuhang Zhang, Daogao Wei, Yawei Zhu, Liang Zhang, Di Wu
With the significant increase in vehicle ownership in our country, urban traffic conditions have become increasingly congested. Low-speed driving has become more prevalent, leading to more frequent instances of starting and braking. Consequently, the issue of low-speed braking flutter has become increasingly prominent.While the brake is in an open environment, the dust and particles in the air and the debris generated by the brake itself will have an impact on the braking behavior. In addition, according to the theory of modal coupling, the braking stability of the vehicle is also affected by other components. In this paper, different dynamic torsional models of braking system are established according to different braking conditions. Through numerical calculation, the influence of tire parameters, road conditions and particles on the friction dynamics characteristics of braking system pairs is explored. The results show that the instability of the brake pair system often occurs at low speed. Different tire slip ratio, tire offset factors and road conditions will lead to different relative motions of the braking system, but the existence of particles in the brake lining-disc interface can enhance the motion stability of the system.
{"title":"Dynamic Characteristics of Three-Body Braking System Considering Tire-Road Friction","authors":"Shenggang Du, Yuhang Zhang, Daogao Wei, Yawei Zhu, Liang Zhang, Di Wu","doi":"10.1115/1.4064058","DOIUrl":"https://doi.org/10.1115/1.4064058","url":null,"abstract":"With the significant increase in vehicle ownership in our country, urban traffic conditions have become increasingly congested. Low-speed driving has become more prevalent, leading to more frequent instances of starting and braking. Consequently, the issue of low-speed braking flutter has become increasingly prominent.While the brake is in an open environment, the dust and particles in the air and the debris generated by the brake itself will have an impact on the braking behavior. In addition, according to the theory of modal coupling, the braking stability of the vehicle is also affected by other components. In this paper, different dynamic torsional models of braking system are established according to different braking conditions. Through numerical calculation, the influence of tire parameters, road conditions and particles on the friction dynamics characteristics of braking system pairs is explored. The results show that the instability of the brake pair system often occurs at low speed. Different tire slip ratio, tire offset factors and road conditions will lead to different relative motions of the braking system, but the existence of particles in the brake lining-disc interface can enhance the motion stability of the system.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"48 11","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139261438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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