Networked Assembly of Affine Physical System Models

2006 ◽  
Author(s):  
E. Motato ◽  
C. Radcliffe
Keyword(s):  
Physical System ◽  
Dynamic Models ◽  
Dynamic Stiffness ◽  
Global Strategy ◽  
Standard Format ◽  
Modular Modeling ◽  
Assembly Algorithm ◽  
System Models ◽  
Stiffness Matrices ◽  
External Behavior

Engineering design is evolving into a global strategy that distributes model information through computer networks. This strategy requires companies to provide dynamic models of supplied components. Component models must be assembled to obtain the product dynamic model. Four characteristics are needed. Specifically, models require a unique standard format, the exchange of model information must be executed in a single-query transmission, the models must describe only external behavior, and the assembly process must be recursive. The Modular Modeling Method (MMM) [1], is a model assembly algorithm that satisfies these requirements. The MMM algorithm assembles linear physical systems models with dynamic stiffness matrices. This paper will extend MMM to nonlinear affine behavior. In an affine system, deviations in the inputs and outputs exhibit a proportional relationship, but the outputs of the system are not zero at zero input [2]. The main reason for developing a process to assemble affine systems is the possibility of using this method to assemble general differentiable nonlinear physical system models performing around a constant operating point.

Networked Assembly of Mechatronic Linear Physical System Models

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Clark J. Radcliffe ◽  
Eliot Motato ◽  
Drew Reichenbach
Keyword(s):  
Physical System ◽  
Dynamic Models ◽  
External Input ◽  
Global Network ◽  
Analytical Models ◽  
Thermal Dynamics ◽  
Efficient System ◽  
Standard Format ◽  
System Models ◽  
Assembly Method

Engineering design is evolving into a global activity. Globally distributed design requires efficient global distribution of models of dynamic physical systems through computer networks. These models must describe the external input-output behavior of the electrical, mechanical, fluid, and thermal dynamics of engineering systems. An efficient system model assembly method is then required to assemble these component system models into a model of a yet higher-level dynamic system. Done recursively, these higher-level system models become possible components for yet higher-level analytical models composed of external model equations in the same standardized format as that of the lowest level components. Real-time, automated exchange, and assembly of engineering dynamic models over a global network requires four characteristics. The models exchanged must have a unique standard format so that they can be exchanged and assembled by an automated process. The exchange of model information must be executed in a single-query transmission to minimize network load. The models must describe only external behavior to protect internal model details. Finally, the assembly process must be recursive so that the transfer and assembly processes do not change with the level of the model exchanged or assembled. This paper will introduce the modular modeling method (MMM), a modeling strategy that satisfies these requirements. The MMM distributes and assembles linear dynamic physical system models with a dynamic matrix representation. Using the MMM method, dynamic models of complex assemblies can be built and distributed while hiding the topology and characteristics of their dynamic subassemblies.

A Model Accuracy and Validation Algorithm

2002 ◽  
Author(s):  
Polat Sendur ◽  
Jeffrey L. Stein ◽  
Huei Peng ◽  
Loucas S. Louca
Keyword(s):  
Physical System ◽  
Dynamic Models ◽  
System Model ◽  
System Response ◽  
Model Accuracy ◽  
Physical Systems ◽  
System Models ◽  
Points Of Interest ◽  
Measured System

Dynamic models of physical systems with physically meaningful states and parameters have become increasingly important, for design, control and even procurement decisions. The successful use of models in these contexts requires that the models be of sufficient quality. However, while algorithms have been developed to help formulate and integrate physical system models, as well as to generate minimum complexity physical system models, algorithms to assess the “quality” of dynamic system models have not been produced. This is true even if the attributes of model are limited to accuracy and validity. The objective of this paper is to introduce a new methodology that systematically quantifies the accuracy of a predicted system response and determines the validity of the physical system model used to predict the system response. The accuracy and validity of the model are evaluated using statistical properties of measured system response. The new algorithm is called Accuracy & Validation Algorithm for Simulation (AVASIM), and is a time-domain perspective comparing the model’s time trajectories at user-defined points of interest as well as over the entire simulation horizon. To illustrate AVASIM, the quality of a handling model of a DaimlerChrysler Grand Cherokee is compared to the measurements obtained from that vehicle subjected to known steering inputs. Results demonstrate that the accuracy and validity of the Grand Cherokee model can be systematically assessed using the proposed methodology, and, thus, AVASIM appears to be a powerful tool for assessing the quality of system models.

scholarly journals VeriPhy: verified controller executables from verified cyber-physical system models

2018 ◽  
Vol 53 (4) ◽  
pp. 617-630 ◽  
Author(s):  
Brandon Bohrer ◽  
Yong Kiam Tan ◽  
Stefan Mitsch ◽  
Magnus O. Myreen ◽  
André Platzer
Keyword(s):  
Physical System ◽  
Cyber Physical System ◽  
System Models

scholarly journals The Physical Basis of Analogies in Physical System Models

Mechatronics ◽  
2005 ◽  
pp. 8-1-8-10
Author(s):  
Neville Hogan ◽  
Peter Breedveld
Keyword(s):  
Physical System ◽  
Physical Basis ◽  
System Models

A New Finding on the Dynamic Stiffness Matrices of Asymmetric and Axisymmetric Shafts

2001 ◽  
Author(s):  
Francesco A. Raffa ◽  
Furio Vatta
Keyword(s):  
Stiffness Matrix ◽  
Dynamic Stiffness ◽  
Equations Of Motion ◽  
Beam Theory ◽  
Rotational Inertia ◽  
Dynamic Stiffness Matrix ◽  
Rayleigh Beam ◽  
Principal Moments Of Inertia ◽  
Stiffness Matrices ◽  
New Finding

Abstract In this paper the dynamic stiffness method is developed to analyze a rotating asymmetric shaft, i.e. a shaft whose transverse section is characterized by dissimilar principal moments of inertia. The shaft is modeled according to the Rayleigh beam theory including the effects of both translational and rotational inertia, and gyroscopic moments. The mathematical description is carried out in a reference system rotating at the shaft speed and is based on the exact solution of the governing differential equations of motion. The exact expressions of the shaft displacements are utilized for deriving the 8 × 8 complex dynamic stiffness matrix of the shaft. A new relationship is obtained which links the dynamic stiffness matrix of the asymmetric shaft to the 4 × 4 real dynamic stiffness matrix of the axisymmetric shaft.

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