The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Yongchun Fang - One of the best experts on this subject based on the ideXlab platform.
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antiswing cargo transportation of underactuated tower crane systems by a nonlinear controller embedded with an Integral Term
IEEE Transactions on Automation Science and Engineering, 2019Co-Authors: Yiming Wu, He Chen, Yongchun FangAbstract:A tower crane is a nonlinear mechatronic system with complicated underactuated characteristics, which is widely used in modern construction sites. At present, most existing methods for tower cranes are proposed by linearizing the original nonlinear dynamics near equilibrium points, which are, thus, prone to suffering from unexpected steady errors due to such factors as unmodeled dynamics, imperfect friction compensation, etc., since they have not included Integral Terms in either controller design or stability analysis. Therefore, in this paper, an improved feedback controller with an elaborately constructed Integral Term is proposed for 3-D tower cranes without linearization, which can achieve both antiswing and positioning control while being able to effectively reduce steady errors in the presence of, e.g., inaccurate friction compensation. Furthermore, asymptotic stability results are proven through rigorous theoretical analysis. Owing to no linearization, the proposed controller is applicable when state variables (e.g., cargo swing angles) are not close enough to the equilibrium points, which makes it suitable for complicated working conditions. Hardware experimental results are included to verify the effectiveness of the proposed controller. Note to Practitioners —This paper is motivated by the requirement of effective control methods for tower cranes. Tower cranes are widely applied in modern construction sites to fulfill cargo transportation tasks. For such systems, the jib slew motion not only enlarges the workspace but also brings more difficulties to suppress unexpected cargo swing during the transportation process. Up until now, most existing methods use simplified system models or need exact model knowledge, which are difficult to reflect real dynamics in many practical situations. To handle these existing problems, in this paper, a novel feedback control approach embedded with an elaborately constructed Integral Term is presented without model linearization. By introducing the Integral Term, even when frictions are inaccurately compensated, steady errors can be reduced effectively and, hence, the positioning accuracy can be improved. Also, the proposed controller can handle parametric uncertainties. By applying the proposed controller, the closed-loop system achieves asymptotic results, which is rigorously proven theoretically. Finally, the effectiveness of the proposed controller is verified by implementing several groups of hardware experiments. In the future studies, we will apply the proposed method in practical applications.
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Antiswing Cargo Transportation of Underactuated Tower Crane Systems by a Nonlinear Controller Embedded With an Integral Term
IEEE Transactions on Automation Science and Engineering, 2019Co-Authors: Yiming Wu, He Chen, Yongchun FangAbstract:A tower crane is a nonlinear mechatronic system with complicated underactuated characteristics, which is widely used in modern construction sites. At present, most existing methods for tower cranes are proposed by linearizing the original nonlinear dynamics near equilibrium points, which are, thus, prone to suffering from unexpected steady errors due to such factors as unmodeled dynamics, imperfect friction compensation, etc., since they have not included Integral Terms in either controller design or stability analysis. Therefore, in this paper, an improved feedback controller with an elaborately constructed Integral Term is proposed for 3-D tower cranes without linearization, which can achieve both antiswing and positioning control while being able to effectively reduce steady errors in the presence of, e.g., inaccurate friction compensation. Furthermore, asymptotic stability results are proven through rigorous theoretical analysis. Owing to no linearization, the proposed controller is applicable when state variables (e.g., cargo swing angles) are not close enough to the equilibrium points, which makes it suitable for complicated working conditions. Hardware experimental results are included to verify the effectiveness of the proposed controller.
Yiming Wu - One of the best experts on this subject based on the ideXlab platform.
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antiswing cargo transportation of underactuated tower crane systems by a nonlinear controller embedded with an Integral Term
IEEE Transactions on Automation Science and Engineering, 2019Co-Authors: Yiming Wu, He Chen, Yongchun FangAbstract:A tower crane is a nonlinear mechatronic system with complicated underactuated characteristics, which is widely used in modern construction sites. At present, most existing methods for tower cranes are proposed by linearizing the original nonlinear dynamics near equilibrium points, which are, thus, prone to suffering from unexpected steady errors due to such factors as unmodeled dynamics, imperfect friction compensation, etc., since they have not included Integral Terms in either controller design or stability analysis. Therefore, in this paper, an improved feedback controller with an elaborately constructed Integral Term is proposed for 3-D tower cranes without linearization, which can achieve both antiswing and positioning control while being able to effectively reduce steady errors in the presence of, e.g., inaccurate friction compensation. Furthermore, asymptotic stability results are proven through rigorous theoretical analysis. Owing to no linearization, the proposed controller is applicable when state variables (e.g., cargo swing angles) are not close enough to the equilibrium points, which makes it suitable for complicated working conditions. Hardware experimental results are included to verify the effectiveness of the proposed controller. Note to Practitioners —This paper is motivated by the requirement of effective control methods for tower cranes. Tower cranes are widely applied in modern construction sites to fulfill cargo transportation tasks. For such systems, the jib slew motion not only enlarges the workspace but also brings more difficulties to suppress unexpected cargo swing during the transportation process. Up until now, most existing methods use simplified system models or need exact model knowledge, which are difficult to reflect real dynamics in many practical situations. To handle these existing problems, in this paper, a novel feedback control approach embedded with an elaborately constructed Integral Term is presented without model linearization. By introducing the Integral Term, even when frictions are inaccurately compensated, steady errors can be reduced effectively and, hence, the positioning accuracy can be improved. Also, the proposed controller can handle parametric uncertainties. By applying the proposed controller, the closed-loop system achieves asymptotic results, which is rigorously proven theoretically. Finally, the effectiveness of the proposed controller is verified by implementing several groups of hardware experiments. In the future studies, we will apply the proposed method in practical applications.
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Antiswing Cargo Transportation of Underactuated Tower Crane Systems by a Nonlinear Controller Embedded With an Integral Term
IEEE Transactions on Automation Science and Engineering, 2019Co-Authors: Yiming Wu, He Chen, Yongchun FangAbstract:A tower crane is a nonlinear mechatronic system with complicated underactuated characteristics, which is widely used in modern construction sites. At present, most existing methods for tower cranes are proposed by linearizing the original nonlinear dynamics near equilibrium points, which are, thus, prone to suffering from unexpected steady errors due to such factors as unmodeled dynamics, imperfect friction compensation, etc., since they have not included Integral Terms in either controller design or stability analysis. Therefore, in this paper, an improved feedback controller with an elaborately constructed Integral Term is proposed for 3-D tower cranes without linearization, which can achieve both antiswing and positioning control while being able to effectively reduce steady errors in the presence of, e.g., inaccurate friction compensation. Furthermore, asymptotic stability results are proven through rigorous theoretical analysis. Owing to no linearization, the proposed controller is applicable when state variables (e.g., cargo swing angles) are not close enough to the equilibrium points, which makes it suitable for complicated working conditions. Hardware experimental results are included to verify the effectiveness of the proposed controller.
A. Kamath - One of the best experts on this subject based on the ideXlab platform.
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A dissipative dynamical systems approach to stability analysis of time delay systems
International Journal of Robust and Nonlinear Control, 2020Co-Authors: V.s. Chellaboina, W.m. Haddad, A. KamathAbstract:In this paper the concepts of dissipativity and the exponential dissipativity are used to provide sufficient conditions for guaranteeing asymptotic stability of a time delay dynamical system. Specifically, representing a time delay dynamical system as a negative feedback interconnection of a finite-dimensional linear dynamical system and an infinite-dimensional time delay operator, we show that the time delay operator is dissipative with respect to a quadratic supply rate and with a storage functional involving an Integral Term identical to the Integral Term appearing in standard Lyapunov–Krasovskii functionals. Finally, using stability of feedback interconnection results for dissipative systems, we develop sufficient conditions for asymptotic stability of time delay dynamical systems. The overall approach provides a dissipativity theoretic interpretation of Lyapunov–Krasovskii functionals for asymptotically stable dynamical systems with arbitrary time delay. Copyright © 2004 John Wiley & Sons, Ltd.
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New sufficient conditions for stability analysis of time delay systems using dissipativity theory
Proceedings of the 2004 American Control Conference, 2004Co-Authors: V.s. Chellaboina, W.m. Haddad, A. KamathAbstract:We extend the concepts of dissipativity and exponential dissipativity to provide new sufficient conditions for guaranteeing asymptotic stability of a time delay dynamical system. Specifically, representing a time delay dynamical system as a negative feedback interconnection of a finite-dimensional linear dynamical system and an infinite-dimensional time delay operator, we show that the time delay operator is dissipative. As a special case of this result we show that the storage functional of the dissipative delay operator involves an Integral Term identical to the Integral Term appearing in standard Lyapunov-Krasovskii functional. Finally, using stability of feedback interconnection results for dissipative systems, we develop new sufficient conditions for asymptotic stability of time delay dynamical systems. The overall approach provides an explicit framework for constructing Lyapunov-Krasovskii functionals as well as deriving new sufficient conditions for stability analysis of asymptotically stable time delay dynamical systems based on the dissipativity properties of the time delay operator.
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A dissipative dynamical systems approach to stability analysis of time delay systems
Proceedings of the 2003 American Control Conference 2003., 2003Co-Authors: V.s. Chellaboina, W.m. Haddad, A. KamathAbstract:In this paper the concepts of dissipativity and the exponential dissipativity are used to provide sufficient conditions for guaranteeing asymptotic stability of a time delay dynamical system. Specifically, representing a time delay dynamical system as a negative feedback interconnection of a finite-dimensional linear dynamical system and an infinite-dimensional time delay operator, we show that the time delay operator is dissipative with respect to a quadratic supply rate and with a storage functional involving an Integral Term identical to the Integral Term appearing in standard Lyapunov-Krasovskii functionals. Finally, using stability of feedback interconnection results for dissipative systems, we develop sufficient conditions for asymptotic stability of time delay dynamical systems. The overall approach provides a systematic framework for constructing Lyapunov-Krasovskii functionals for asymptotically stable time delay dynamical systems based on the dissipativity properties of the time delay operator.
Hong Hu - One of the best experts on this subject based on the ideXlab platform.
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Transonic wing flow computations using the field-panel method with a shock-fitting technique
Engineering Analysis With Boundary Elements, 1995Co-Authors: Hong HuAbstract:An Integral equation field-panel scheme for solving the full-potential equation for compressible flows with and without shocks is presented. The full-potential equation is written in the form of the Poisson's equation. Compressibility is treated as non-homogeneity. The Integral equation solution in Terms of velocity field is obtained by Green's theorem. The solution consists of wing (or a general body) surface Integral Term(s) of vorticity/source distribution(s), wake surface Integral Term(s) of free-vortex sheet(s), a volume Integral Term of compressibility over a small limited domain around the source of disturbance, and a shock surface Integral Term of source distributions for the shock-fitting purpose. Solutions are obtained through an iterative procedure. Instead of using a grid (field-panel) refinement procedure, a shock-fitting technique is used to fit the shock. The present scheme is applied to non-lifting flows around both sharp and round leading edge rectangular wings at high-subsonic and transonic flow conditions.
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Development of a shock-fitting field-panel method for 3D transonic flows
Computational Mechanics, 1995Co-Authors: Hong HuAbstract:The paper presents the development of a shock-fitting field-panel method for three-dimension (3D) transonic flows. In this method, the full-potential equation, written in the form of the Poisson's equation, is solved by Integral equation field-panel method. The solution consists of a wing surface source panel Integral Term, a field-volume panel Integral Term of compressibility over a small limited domain, and a shock panel Integral Term. Due to the non-linearity of flows, solutions are obtained through an iterative procedure. Instead of using a field-panel refinement procedure, a shock-fitting technique is used to fit the shock. Finally, numerical examples are provided to demonstrate the accuracy of the method.
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A 3D IEM for Compressible Wing Flows With and Without Shocks
Boundary Elements in Fluid Dynamics, 1992Co-Authors: Hong HuAbstract:An Integral equation (or called field-panel, field-boundary element) scheme for solving the full-potential equation for incompressible and compressible flows with and without shocks has been developed. The full-potential equation has been written in the form of the Poisson’s equation. Compressibility has been treated as non-homogeneity. The Integral equation solution in Terms of velocity field is obtained by the Green’s theorem. The solution consists of wing (or a general body) surface (boundary elements) Integral Term(s) of vorticity/source distribution(s), wake surface (boundary elements) Integral Term(s) of free-vortex sheet(s), a volume (field-elements) Integral Term of compressibility over a small limited domain around the source of disturbance, and a shock surface (boundary elements) Integral Term of source distributions. Solution is obtained through an iterative procedure for non-linear compressible flows. To be consistent with the mixed-nature of transonic flows, the Murman-Cole type-difference scheme is used to compute the derivatives of the density. The present scheme is applied to flows around a rectangular wing with circular-arc section at incompressible, high- subsonic and transonic flow conditions.
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Unsteady transonic wing flow computations using field-boundary element methods
Engineering Analysis With Boundary Elements, 1992Co-Authors: Hong HuAbstract:Abstract An unsteady Integral equation (or called field-panel, field-boundary element) scheme for solving the full-potential equation for transonic unsteady wing flows has been developed. The unsteady full-potential equation has been written in a moving frame of reference, in the form of the Poisson's equation. Compressibility and unsteadiness have been treated as non-homogeneity. The Integral equation solution in Terms of velocity field is obtained by the Green's theorem. The solution consists of a wing surface (boundary elements) Integral Term of vorticity distribution, a wake surface (boundary elements) Integral Term of free-vortex sheet and a volume (field-elements) Integral Term of compressibility and unsteadiness over a small limited domain around the wing. Numerical solutions are obtained by a time-marching, iterative procedure. Time-derivative Term is calculated by a second-order backward finite-difference scheme. To be consistent with the mixed-nature of flows, the Murman-Cole type-difference scheme is used to compute the derivatives of the density. The present scheme is applied to flows around a rectangular wing at transonic speed undergoing acceleration motion and transient pitching motion, respectively. The time history of wing surface pressure distributions has been presented.
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Application of the Integral Equation Method to Flows Around a Wing with Circular-Arc Section
Boundary Elements XIII, 1991Co-Authors: Hong HuAbstract:An Integral equation (or called field-panel, field-boundary element) scheme for solving the full-potential equation for transonic flows has been developed. The full-potential equation has been written in the form of the Poisson’s equation. Compressibility has been treated as non-homogeneity. The Integral equation solution in Terms of velocity field is obtained by the Green’s theorem. The solution consists of surface (boundary elements) Integral Term(s) of vorticity/source distributions), wake surface (boundary elements) Integral Term(s) of free-vortex sheet(s) and a volume (field-elements) Integral Term of compressibility over a small limited domain around the source of disturbance. Solution procedure is an iterative procedure for non-linear flows. To consist with the mixed-nature of transonic flows, the Murman-Cole type-difference scheme is used to compute the derivatives of the density for non-linear flows. The present scheme is applied to flows around a rectangular wing with circular-arc section.
He Chen - One of the best experts on this subject based on the ideXlab platform.
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antiswing cargo transportation of underactuated tower crane systems by a nonlinear controller embedded with an Integral Term
IEEE Transactions on Automation Science and Engineering, 2019Co-Authors: Yiming Wu, He Chen, Yongchun FangAbstract:A tower crane is a nonlinear mechatronic system with complicated underactuated characteristics, which is widely used in modern construction sites. At present, most existing methods for tower cranes are proposed by linearizing the original nonlinear dynamics near equilibrium points, which are, thus, prone to suffering from unexpected steady errors due to such factors as unmodeled dynamics, imperfect friction compensation, etc., since they have not included Integral Terms in either controller design or stability analysis. Therefore, in this paper, an improved feedback controller with an elaborately constructed Integral Term is proposed for 3-D tower cranes without linearization, which can achieve both antiswing and positioning control while being able to effectively reduce steady errors in the presence of, e.g., inaccurate friction compensation. Furthermore, asymptotic stability results are proven through rigorous theoretical analysis. Owing to no linearization, the proposed controller is applicable when state variables (e.g., cargo swing angles) are not close enough to the equilibrium points, which makes it suitable for complicated working conditions. Hardware experimental results are included to verify the effectiveness of the proposed controller. Note to Practitioners —This paper is motivated by the requirement of effective control methods for tower cranes. Tower cranes are widely applied in modern construction sites to fulfill cargo transportation tasks. For such systems, the jib slew motion not only enlarges the workspace but also brings more difficulties to suppress unexpected cargo swing during the transportation process. Up until now, most existing methods use simplified system models or need exact model knowledge, which are difficult to reflect real dynamics in many practical situations. To handle these existing problems, in this paper, a novel feedback control approach embedded with an elaborately constructed Integral Term is presented without model linearization. By introducing the Integral Term, even when frictions are inaccurately compensated, steady errors can be reduced effectively and, hence, the positioning accuracy can be improved. Also, the proposed controller can handle parametric uncertainties. By applying the proposed controller, the closed-loop system achieves asymptotic results, which is rigorously proven theoretically. Finally, the effectiveness of the proposed controller is verified by implementing several groups of hardware experiments. In the future studies, we will apply the proposed method in practical applications.
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Antiswing Cargo Transportation of Underactuated Tower Crane Systems by a Nonlinear Controller Embedded With an Integral Term
IEEE Transactions on Automation Science and Engineering, 2019Co-Authors: Yiming Wu, He Chen, Yongchun FangAbstract:A tower crane is a nonlinear mechatronic system with complicated underactuated characteristics, which is widely used in modern construction sites. At present, most existing methods for tower cranes are proposed by linearizing the original nonlinear dynamics near equilibrium points, which are, thus, prone to suffering from unexpected steady errors due to such factors as unmodeled dynamics, imperfect friction compensation, etc., since they have not included Integral Terms in either controller design or stability analysis. Therefore, in this paper, an improved feedback controller with an elaborately constructed Integral Term is proposed for 3-D tower cranes without linearization, which can achieve both antiswing and positioning control while being able to effectively reduce steady errors in the presence of, e.g., inaccurate friction compensation. Furthermore, asymptotic stability results are proven through rigorous theoretical analysis. Owing to no linearization, the proposed controller is applicable when state variables (e.g., cargo swing angles) are not close enough to the equilibrium points, which makes it suitable for complicated working conditions. Hardware experimental results are included to verify the effectiveness of the proposed controller.