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Zeid, Ashraf A.; Overholt, James L.; Beck, Ronald R.
doi: 10.1177/003754979406200102pmid: N/A
This paper demonstrates how to use an interpretive-type simulation language, such as MATRIXx or SIMULINK, in the simulation of multibody systems. Functional blocks that contain details of the dynamics of a rigid body and of the equations of several joints were created by using the graphical user interface of MATRIXx. Models of complex multibody systems are built by graphically selecting, duplicating, and connecting appropriate blocks of rigid bodies and joints. This modularity is afforded because joints are formulated using the explicit singularly perturbed formulation. The singularly perturbed formulation, originally developed in bond graph language, is based on modeling infinitesimal defonnation in joints, a characteristic of realistic multibody joints.Bond graphs are graphical models of multi-energy doinain dynamic systems that depict and account for the power structure in the system. In this paper, block diagrams that were obtained from an algorithmic translation of joint bond graphs are coded using the simulation language graphical interface. The methodology is demonstrated by modeling the dynamic behavior of a complex multibody system; namely, a Stewart platform.Because this formulation is explicit, it sets the stage for the simulation of very large- scale multibody systems by exploiting parallelisin of novel computer architectures.
doi: 10.1177/003754979406200103pmid: N/A
The paper describes an extension to a standard, block-structured, interactive simulation language in which colours are used to indicate the levels of variables in the simulated process. A coding system is used to classify the level of simulated process variables into three regions of safe, unsafe and dangerous operation, represented by green, yellow and red colours respectively. The enhanced simulation package facilitates controller development for industrial plant and avoids dangerous levels being overlooked in the simulation of prototype systems prior to their implementation on plant. The use of the enhanced facility is demonstrated by the simulation of the electrode drive system and controller for an electric arc furnace.
Moshell, J. Michael; Blau, Brian; Li, Xin; Lisle, Curtis
doi: 10.1177/003754979406200105pmid: N/A
While many are familiar with flight simulators, there is also a growing body of ground-based simulation training systems. The Army/DARPA sponsored SIMNET project (Nelms 1988) involved over 200 armor and aircraft simulators in a complex network, designed to teach combined arms combat skills. The follow-on Close Combat Tactical Trainer (CCTT) project will be the largest training simulator acquisition in history.In addition, realtime interactive simula tion is moving beyond military training into the potentially much larger market of commercial, entertainment and educational applications currently being called "Virtual Reality" (Furness 1988). However, no existing realtime simulation supports a truly interactive world. In particular, the terrain (soil, water and vegetation) is nearly or completely immutable in today's simula tors. In a word, the terrain is not dynamic.This Project explores the hypothesis that it is economically feasible to construct networked realtime simulators which incorporate useful simulations of dynamic terrain phenomena. The authors have evaticated the computational requirements of realtime graphical dynamic terrain simula tion with both theoretical models and prototypes, and conclude that useful levels of terrain dynamics can be incorporated in the next generation of low-cost, high-volume training simulators and virtual environ ments.
Baveco, J.M.; Smeulders, A.M.W.
doi: 10.1177/003754979406200106pmid: N/A
The object-oriented programming environment Smalltalk is used to implement a tool for modeling and simulation of ecological systems. This PC-based tool makes it possible, and easy, to represent individuals explicitly in the simulation, and to integrate the individual-based approach with a traditional population/concentration-based approach. Object-oriented programming is used to allow for an efficient development of models. The properties of Smalltalk are exploited to make testing and investigation of the models occur interactively, supported by a user-friendly interface. In the paper, modeling and simulation concepts and elements of object- oriented programming as they relate to an individual-based approach, are introduced. The simulation extension in question (EcoTalk) is described. Two applications that make use of EcoTalk are presented, both related to population-dynamics. The discussion centers on practical implications of the approach, e.g. the system characteristics that can be expressed in EcoTalk. An indication of the performance of an application is given. It is concluded that, at present, EcoTalk can be used for medium-sized applications.
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