Discrete Time Transfer Matrix Method Research Articles

Riccati Discrete Time Transfer Matrix Method for Dynamic Modeling and Simulation of an Underwater Towed System

Efficient, precise dynamic modeling and control of complex underwater towed systems has become a research focus in the field of multibody dynamics. In this paper, based on finite segment model of cable, by defining the new state vectors and deducing the new transfer equations of underwater towed systems, a new highly efficient method for dynamic modeling and simulation of underwater towed systems is presented and the pay-out/reel-in process of towed cable is studied. The computational efficiency and numerical stability of the proposed method are discussed. When using the method to study the dynamics of underwater towed systems, it avoids the global dynamic equations of system, and simplifies solving procedure. Irrespective of the degree of freedom of underwater towed system, the matrices involved in the proposed method are always very small, which greatly improve the computational efficiency and avoids the computing difficulties caused by too high matrix orders for complex underwater towed systems. Formulations of the method as well as numerical simulations are given to validate the proposed method.

Discrete time transfer matrix method for dynamics of multibody system with flexible beams moving in space

In this paper, by defining new state vectors and developing new transfer matrices of various elements moving in space, the discrete time transfer matrix method of multi-rigid-flexible-body system is expanded to study the dynamics of multibody system with flexible beams moving in space. Formulations and numerical example of a rigid-flexible-body three pendulums system moving in space are given to validate the method. Using the new method to study the dynamics of multi-rigid-flexible-body system moving in space, the global dynamics equations of system are not needed, the orders of involved matrices of the system are very low and the computational speed is high, irrespective of the size of the system. The new method is simple, straightforward, practical, and provides a powerful tool for multi-rigid-flexible-body system dynamics.

Dynamics and genetic fuzzy neural network vibration control design of a smart flexible four-bar linkage mechanism

In this paper, a dynamic modeling method and an active vibration control scheme for a smart flexible four-bar linkage mechanism featuring piezoelectric actuators and strain gauge sensors are presented. The dynamics of this smart mechanism is described by the Discrete Time Transfer Matrix Method of Multibody System (MS-DTTMM). Then a nonlinear fuzzy neural network control is employed to suppress the vibration of this smart mechanism. For improving the dynamic performance of the fuzzy neural network, a genetic algorithm based on the MS-DTTMM is designed offline to tune the initial parameters of the fuzzy neural network. The MS-DTTMM avoids the global dynamics equations of the system, which results in the matrices involved are always very small, so the computational efficiency of the dynamic analysis and control system optimization can be greatly improved. Formulations of the method as well as a numerical simulation are given to demonstrate the proposed dynamic method and control scheme.

Discrete time transfer matrix method for dynamics analysis of complex weapon systems

Efficient, precise dynamic modeling and analysis for complex weapon systems have become more and more important in their dynamic design and performance optimizing. As a new method developed in recent years, the discrete time transfer matrix method of multibody system is highly efficient for multibody system dynamics. In this paper, taking a shipboard gun system as an example, by deducing some new transfer equations of elements, the discrete time transfer matrix method of multibody system is used to solve the dynamics problems of complex rigid-flexible coupling weapon systems successfully. This method does not need the global dynamic equations of system and has the low order of system matrix, high computational efficiency. The proposed method has advantages for dynamic design of complex weapon systems, and can be carried over straightforwardly to other complex mechanical systems.

Discrete Time Transfer Matrix Method for Dynamic Modeling of Complex Spacecraft With Flexible Appendages

Efficient, precise dynamic analysis for a complex spacecraft has become a research focus in the field of spacecraft dynamics. In this paper, by combining discrete time transfer matrix method of multibody system and finite element method, the transfer equations and transfer matrices of typical elements of spacecrafts are developed, and a high-efficient dynamic modeling method is developed for high-speed computation of spacecraft dynamics. Compared with ordinary dynamic methods, the proposed method does not need the global dynamic equations of system and has the low order of system matrix, high computational efficiency. This method has more advantages for dynamic modeling and real-time control of complex spacecrafts. Formulations of the proposed method as well as a numerical example of a spacecraft with a flexible solar panel are given to validate the method.

Erratum to: New efficient method for dynamic modeling and simulation of flexible multibody systems moving in plane

Efficient, precise dynamic analysis for general flexible multibody systems has become a research focus in the field of flexible multibody dynamics. In this paper, the finite element method and component mode synthesis are introduced to describe the deformations of the flexible components, and the dynamic equations of flexible bodies moving in plane are deduced. By combining the discrete time transfer matrix method of multibody system with these dynamic equations of flexible component, the transfer equations and transfer matrices of flexible bodies moving in plane are developed. Finally, a high-efficient dynamic modeling method and its algorithm are presented for high-speed computation of general flexible multibody dynamics. Compared with the ordinary dynamics methods, the proposed method combines the strengths of the transfer matrix method and finite element method. It does not need the global dynamic equations of system and has the low order of system matrix and high computational efficiency. This method can be applied to solve the dynamics problems of flexible multibody systems containing irregularly shaped flexible components. It has advantages for dynamic design of complex flexible multibody systems. Formulations as well as a numerical example of a multi-rigid-flexible-body system containing irregularly shaped flexible components are given to validate the method.

Discrete time transfer matrix method for dynamics of multibody system with real-time control

By taking the control and feedback parameters into account in state vectors, defining new state vectors and deducing new transfer equations and transfer matrices for actuator, controlled element and feedback element, a new method named as the discrete time transfer matrix method for controlled multibody system (CMS) is developed to study dynamics of CMS with real-time control in this paper. This method does not need the global dynamics equations of system. It has the modeling flexibility, low order of system matrix, high computational efficiency, and is efficient for general CMS. Compared with the ordinary dynamics methods, the proposed method has more advantages for dynamics design and real-time control of a complex CMS. Adopting the PID adaptive controller and modal velocity feedback control on PZT actuators, and applying the proposed method and ordinary dynamics method, respectively, the tip trajectory tracking for a flexible manipulator is carried out. Formulations of the method as well as numerical simulation are given to validate the proposed method.

New method for dynamics modelling and analysis on a flexible plate undergoing large overall motion

Flexible plates are general components in many engineering fields such as aircrafts and vehicles, and their efficient dynamics analysis has an important significance. In this article, by combining discrete time transfer matrix method of multi-body system (MS-DT-TMM) with finite-element method (FEM), the dynamics equations of a flexible plate moving in space are deduced, and its transfer equation and transfer matrix are presented. Finally, a high-efficient modelling method is developed for dynamics analysis on a flexible plate undergoing large overall motion. Compared with ordinary dynamics methods, this method combines the modelling flexibility of MS-DT-TMM with applicability for the two-dimension structure of FEM. By using this method, the global dynamics equations of the system are not needed, the orders of involved matrices are always very small, and the computational speed is high irrespective of the size of the system. The method has advantages for dynamics design of complex flexible multi-body systems (FMS) with flexible plates. Formulations of the method as well as a numerical example of a FMS with a rectangular flexible plate are given to validate the method.

Discrete time transfer matrix method for dynamics of a multi-rigid-flexible-body system moving in plane

A new method of multi-body system (MS) dynamics, named discrete time transfer matrix method of multi-body system (MS-DT-TMM), has been developed to study multi-rigid-body system dynamics in recent years. When using this method, global dynamics equations of the system are not needed and the orders of involved system matrices are always very small. By defining new state vectors and developing new transfer matrices for a multi-rigid-flexible-body system (MRFS) to expand the MS-DT-TMM, a new method, named discrete time transfer matrix method of MRFS (MRFS-DT-TMM), has been developed to study MRFS dynamics in this article. If MRFS-DT-TMM is used, as an MS-DT-TMM, the global dynamics equations of the systems are not needed in the study of MRFS dynamics, the orders of involved matrices are always very small, and the computational speed is high irrespective of the size of an MRFS. This method is simple, straightforward, and practical, and provides a powerful tool for MRFS dynamics. Formulations of the method as well as numerical examples of MRFS dynamics are given to validate the method.

Riccati discrete time transfer matrix method for elastic beam undergoing large overall motion

An efficient method for dynamics simulation for elastic beam with large overall spatial motion and nonlinear deformation, namely, the Riccati discrete time transfer matrix method (Riccati-DT-TMM), is proposed in this investigation. With finite segments, continuous deformation field of a beam can be decomposed into many rigid bodies connected by rotational springs. Discrete time transfer matrices of rigid bodies and rotational springs are used to analyze the dynamic characteristic of the beam, and the Riccati transform is used to improve the numerical stability of discrete time transfer matrix method of multibody system dynamics. A predictor-corrector method is used to improve the numerical accuracy of the Riccati-DT-TMM. Using the Riccati-DT-TMM in dynamics analysis, the global dynamics equations of the system are not needed and the computation time required increases linearly with the system’s number of degrees of freedom. Three numerical examples are given to validate the method for the dynamic simulation of a geometric nonlinear beam undergoing large overall motion.

Discrete Time Transfer Matrix Method for Multibody System Dynamics

A new method for multibody system dynamics is proposed in this paper. This method, named as discrete time transfer matrix method of multibody system (MS-DT-TMM), combines and expands the advantages of the transfer matrix method (TMM), transfer matrix method of vibration of multibody system (MS-TMM), discrete time transfer matrix method (DT-TMM) and the numerical integration procedure. It does not need the global dynamics equations for the study of multibody system dynamics. It has the modeling flexibility and a small size of matrices, and can be applied to a wide range of problems including multi-rigid-body system dynamics and multi-flexible-body system dynamics. This method is simple, straightforward, practical, and provides a powerful tool for the study of multibody system dynamics. Formulations of the method as well as some numerical examples of multi-rigid-body system dynamics and multi-flexible-body system dynamics to validate the method are given.

A new transfer matrix method for response analysis of large dynamic systems

A new transfer matrix method for the dynamic response analysis of large dynamic systems is proposed. This method, named as discrete time-transfer matrix method (DT-TMM), is based on the conventional transfer matrix methods and the numerical solution procedures of differential equations. It combines the advantages of both of these methods. Formulation of the method as well as some numerical examples to check the viability of the method are given. Also identified are several possible areas of applications as well as the possible sources of errors.