Digital Simulation System Research Articles

Research on the Real-Time Simulation System Design for Missile Based on RT-LAB

Abstract A semi-physical simulation system is developed based on the RT-LAB real-time simulation environment which is used to process simulation test of missile guidance controlling system. The system adopts design idea of modularization, development of all sub-system together and it integrates the Hi-fi missile aerodynamics environment, missile boron computer system, inertia measurement unit, high accurate aviation posture simulator, real missile boron port equipment, three-dimensional view and data backup system into one so that the performance of guidance controlling algorithm could be reflected comprehensively, directly and really. According to the comparison between test result of digital simulation and semi-physical system simulation, the feasibility of semi-physical simulation could be certified so that under the semi-physical simulation environment, more real and effective test could be checked for guidance controlling algorithm.

Digital Simulation of the Generalized Unified Power Flow Controller System with 60-Pulse GTO-Based Voltage Source Converter

The Generalized Unified Power Flow Controller (GUPFC) is a Voltage Source Converter (VSC) based Flexible AC Transmission System (FACTS) controller for shunt and series compensation among the multiline transmission systems of a substation. The paper proposes a full model comprising of 60-pulse Gate Turn-Off thyristor VSC that is constructed becomes the GUPFC in digital simulation system and investigates the dynamic operation of control scheme for shunt and two series VSC for active and reactive power compensation and voltage stabilization of the electric grid network. The complete digital simulation of the shunt VSC operating as a Static Synchronous Compensator (STATCOM) controlling voltage at bus and two series VSC operating as a Static Synchronous Series Capacitor (SSSC) controlling injected voltage, while keeping injected voltage in quadrature with current within the power system is performed in the MATLAB/Simulink environment using the Power System Block set (PSB). The GUPFC, control system scheme and the electric grid network are modelled by specific electric blocks from the power system block set. The controllers for the shunt VSC and two series VSCs are pre- sented in this paper based on the decoupled current control strategy. The performance of GUPFC scheme connected to the 500-kV grid is evaluated. The proposed GUPFC controller scheme is fully validated by digital simulation.

Integration of Behavioral Models in the Full-Field TLM Method

The accurate simulation of digital circuits requires the inclusion of field phenomena. Issues such as signal integrity, crosstalk, and external EMI are of paramount importance in the design stage, due to the decreasing feature size and increasing clock frequency of modern digital systems. This paper addresses issues with the incorporation of field phenomena in the simulation of digital systems, by embedding behavioral descriptions of digital ICs into a full wave field model. The paper successfully simulates digital circuits incorporating the external electromagnetic interference (EMI) environment of operation; further research is required to incorporate the internal EMI effects in the IC silicon. The transmission-line modeling method is used for the field model, while the input/output buffer information specification models the digital IC behavior.

The Research of Digital Proving Ground Simulation System Based on HLA

Digital proving ground, is modern shooting range, of high degree automation and integration, based on the digital information network covering the entire area of the proving ground, replied on highly visual trial and direction, connecting various proving grounds and each tache of the trial with computer-based digital communication subsystems and the information system platform, realizing the data identification, collection, transmission, processing, sharing and use of the information. This article based on the basic concepts, methods and principles of HLA, the function and characteristic of proving ground are analyzed, and according to the basic concept, method and principle of HLA, the system design of the distributed digital Proving ground missile penetration simulation system were carried on. On this foundation, system structure of the system was built, and the realization method of federation members classification and the design of FOM / SOM and members interface were introduced.

The Establish of Digital Simulation System on Continuous Cross-Flow Dryer

Drying plays an important role in the post-harvesting process of grain, and the quality of the corn after drying has received an increasing concern. The mathematical model of grain drying plays an essential role in developing grain dryer structure and obtaining the drying technological parameters. Furthermore, an accurate mathematical model is a reference for automated control during drying process. In this paper, using mathematical models and quality model of the corn drying process, a digital simulation of corn drying machine system based on a virtual instrument was established for 5HSZ dryer. Finally, an on-line measurement and automated control software of grain parameters were developed providing the changes of moisture, temperature, humidity, and germination rate in the process of drying. The experimental results show that the simulation result is valid, which has practical merit of operation and technical optimization of dryer.

Real Time Hybrid Simulation of Electrical Power Systems: Concept, Tools, Field Experience and Smart Grid Challenges

An article discusses achievements in the field of real time hybrid simulation of electrical power systems and their application for smart grid tasks solution. The developed real time hybrid simulation concept and tools are introduced as an alternative to digital simulation systems that are currently widely spread. To substantiate this, the article proposes some factors determining the preference of hybrid simulation approach to numerical methods used in digital simulators. A number of accomplished projects and problems solved in the context of these projects are given to confirm the relevancy, efficiency and viability of the introduced approach of real time hybrid simulation.

Development of a Distributed Representative Human Model Generation and Analysis System for Multiple-Size Product Design

Objective: The aim of this study is to develop a distributed representative human model(DRHM) generation and analysis system. Background: DRHMs are used for a product with multiple-size categories such as clothing and shoes. It is not easy for a product designer to explore an optimal sizing system by applying various distributed methods because of their complexity and time demand. Method: Studies related to DRHM generation were reviewed and the RHM generation interfaces of three digital human model simulation systems(Jack<SUP>®</SUP>, RAMSIS<SUP>®</SUP>, and CATIA Human<SUP>®</SUP>) were reviewed. Results: DRHM generation steps are implemented by providing sophisticated interfaces which offer various statistical techniques and visualization methods with ease. Conclusion: The DRHM system can analyze the multivariate accommodation percentage of a sizing system, provide body sizes of generated DRHMs, and visualize generated grids and DRHMs. Application: The DRHM generation and analysis system can be of great use to determine an optimal sizing system for a multiple-size product by comparing various sizing system candidates.

Evaluation of Driving Posture Prediction in Digital Human Simulation Using RAMSIS(R)

For proper ergonomic evaluation using a digital human model simulation (DHMS) system such as RAMSIS®, postures of a humanoid for designated tasks need to be predicted accurately. The present study ...

Flight control iron bird based on passive electric‐hydraulic servo loading system

PurposeThe purpose of this paper is to develop a novel type of full‐size flight control iron bird based on a passive electronic hydraulic servo loading system.Design/methodology/approachOn the basis of mathematical modeling of passive loading system math model, the detailed design process of the flight control iron bird is presented. Subsequently, the system digital simulation and physical verification are also given.FindingsExperimental results show that the proposed approach can reduce the redundant forces and improve the system dynamic and force‐tracking accuracy.Practical implicationsThis newly‐developed flight control iron bird system has been successfully applied in the flight control system design of some fighters.Originality/valueThe proposed approach for flight control iron bird is new and significant for the design of fighter flight control systems.

Radiative Transfer Modeling and Monte Carlo Simulating of a New Digital Airborne Camera

Application of digital aerial camera was a milestone in the development of Photogrammetry and Remote Sensing. The new digital sensor leads to the changes of remote sensing imaging models. Generally, remote sensing imaging models have two kinds: geometric model and radiative model, in which radiative model mainly focus on the radiative quality of remote sensing images. In this paper, a new kind of airborne camera, namely Twice Imaging Digital Camera (TIDC), is introduced, which integrates the advantages of film airborne camera and digital one. It adopts twice imaging techniques to acquire large format, strict central projection images. The radiative transfer model of TIDC is built on the physical processing of digital imaging. The intermediate imaging device of TIDC influences digital images’ quality badly, such as luminous intensity distribution, decay and noise. For this reason, the approach of light tracing based on Monte Carlo is used to simulate radiative transfer in TIDC and test the performance of the intermediate imaging device. The importance of this work is: The Monte Carlo simulating experiment proposed by this paper can be widely applied in the simulation and modeling of other digital imaging systems, and has great practical value in the evaluation and optimization of image quality, the improvement of remote sending imaging system, as well as the estimate of image acquirement results.

A System for 3D Digital Assembly Process Planning and Simulation in Airplane Manufacturing Enterprises

The 3D assembly process planning and simulation system can improve the product manufacturing level in airplane manufacturing enterprises, but now there is few system of this kind. So we design a system named Digital Virtual Airplane Assembly Process Planning and Simulation System (DVA2P2S2) to improve the situation. Firstly, we design the system’s structure with data support, systems integration and functions development and user application as its three levels. Secondly, its running flow is introduced. Thirdly, two key technologies which are 3D digital assembly process structure and the method of automatic creation of simulation file are discussed. At last, we set a subassembly of an airplane to validate the DVA2P2S2. The result shows that the DVA2P2S2 is in accordance with the Concurrent Engineering’s requirements, and it can improve the work efficiency and reduce the process design iteration and cycle significantly.

Design of the Digital Simulation System for Corrosion Damage on Marine Steel Structures

Corrosion of ocean engineering steel structures leads huge economic loses each year. To decrease corrosive loses and guarantee the safety of ocean steel structures, on the basis of Database on Corrosion of Ocean Engineering Materials and Structures (DCOEMS), the overall architecture of a digital simulation system is proposed based on the collection of existing models of corrosion damage on marine steel structures. Typical models involving uniform corrosion, pitting corrosion, stress corrosion and corrosion fatigue are sorted out and integrated in the simulation system which makes a thorough analysis for calculation and principle of professional module. The effective integration of corrosion damage, structural simulation and visualization is implemented successfully. It achieves the applications of the digital simulation. In the case of prediction and evaluation, it lays a good foundation for the development of the simulation system with independent intellectual property rights.

Real-time digital simulation of power electronics systems with Neutral Point Piloted multilevel inverter using FPGA

Most of actual real time simulation platforms have practically about ten microseconds as minimum calculation time step, mainly due to computation limits such as processing speed, architecture adequacy and modeling complexities. Therefore, simulation of fast switching converters’ instantaneous models requires smaller computing time step. The approach presented in this paper proposes an answer to such limited modeling accuracies and computational bandwidth of the currently available digital simulators.As an example, the authors present a low cost, flexible and high performance FPGA-based real-time digital simulator for a complete complex power system with Neutral Point Piloted (NPP) three-level inverter. The proposed real-time simulator can model accurately and efficiently the complete power system, reducing costs, physical space and avoiding any damage to the actual equipment in the case of any dysfunction of the digital controller prototype. The converter model is computed at a small fixed time step as low as 100ns. Such a computation time step allows high precision account of the gating signals and thus avoids averaging methods and event compensations. Moreover, a novel high performance model of the NPP three-level inverter has also been proposed for FPGA implementation. The proposed FPGA-based simulator models the environment of the NPP converter: the dc link, the RLE load and the digital controller and gating signals. FPGA-based real time simulation results are presented and compared with offline results obtained using PLECS software. They validate the efficiency and accuracy of the modeling for the proposed high performance FPGA-based real-time simulation approach. This paper also introduces new potential FPGA-based applications such as low cost real time simulator for power systems by developing a library of flexible and portable models for power converters, electrical machines and drives.

SU-GG-T-258: Solutions to Transforming a Radiotherapy Clinic with Multigenerational Equipment into a Paperless and Filmless Facility

Purpose: To present solutions to transforming a radiation therapy clinic with multigenerational equipment to a paperless and filmless facility. Methods and Materials: Becoming paperless and filmless (digital) is not only more efficient and cost effective but also more environmentally friendly, however not all equipped systems are digital ready. Here we present in‐house developed digital solutions for those clinics with a similar clinical setting and the inclination of becoming digital: CT and analog simulators, Philips Pinnacle3RTP systems, BrainLAB iPlan RTP systems, conventional LINACs with IGRT capabilities, TomoTherapy units and planning systems, brachytherapy planning and delivery systems, stereotactic radiosurgery modalities and hyperthermia apparatus. A few software systems have been developed to either upgrade purchased systems or interface involved ones. System customization procedures were also performed to get them ready for a digital clinic. Results: An add‐on system, PortalSim, was developed to transform a conventional analog simulator to a digital fluoroscopy and dynamic simulation system with DICOM connectivity; a RT image pumping utility, iPump, was devised to interface BrainLAB ExacTrac IGRT system and Record and Verify (RV a DICOM screen dumping tool, ScreenBee, was created to capture computer screen of any system that lacks the effective communication channel with R&V system. Some RTP systems have been customized to meet digital requirements. As a result, all clinical data and documents from plans to quality assurance reports are consolidated in one place in digital form. Conclusion: Having a centralized data management clinical setting without using paper and radiographic film is the way to go for a digital radiation therapy clinic. Scanning everything is one of the solutions some may think of, but it is laborious and not truly paperless. There are better solutions by in‐house system development and system customization.

The benefit of accounting for DQE variations in simulated dose reduction of digital radiographic systems

Adding noise to clinical radiographs to simulate dose reduction can be used to investigate the relationship between dose level and clinical image quality without exposing patients to additional radiation. The purpose of the present paper was to examine the benefits of using a method that accounts for detective quantum efficiency (DQE) variations that may occur in different dose ranges in the simulated dose reduction process. A method initially intended for simulated dose reduction in tomosynthesis was applied to extremely low-dose posterioanterior radiographs of an anthropomorphic chest phantom, selected from a group of projection images included in a tomosynthesis examination and compared with a previous method that do not account for DQE variations. A comparison of images simulated to be collected at a lower dose level (73 % of the original dose level) and images actually collected at this lower dose level revealed that the error in the integrated normalised noise power spectrum was smaller than 4 % for the method that accounts for DQE variations in the simulated dose reduction, whereas the error was larger than 20 % for the previous method. This indicates that an increased validity in dose reduction simulation of digital radiographic systems is obtained with a method accounting for DQE variations.

Digital Camera Imaging System Simulation

A digital camera is a complex system including a lens, a sensor (physics and circuits), and a digital image processor, where each component is a sophisticated system on its own. Since prototyping a digital camera is very expensive, it is highly desirable to have the capability to explore the system design tradeoffs and preview the system output ahead of time. An empirical digital imaging system simulation that aims to achieve such a goal is presented. It traces the photons reflected by the objects in a scene through the optics and color filter array, converts photons into electrons with consideration of noise introduced by the system, quantizes the accumulated voltage to digital counts by an analog-to-digital converter, and generates a Bayer raw image just as a real camera does. The simulated images are validated against real system outputs and show a close resemblance to the images captured under similar condition at all illumination levels.

Wave digital simulation of passive systems in linear state‐space form

AbstractThis paper deals with wave digital modeling of passive state‐space models. The set of differential equations must be of linear state‐space form, but all parameters can be time‐variant and/or nonlinear. For such state‐space models, a canonical internally passive reference circuit is presented and used for deriving wave digital structures. In order to show the usability, special solutions for important basic linear time‐variant models are compared with wave digital simulation results. Moreover, the wave digital modeling of a nonlinear and time‐variant oscillator is discussed. Especially for a lossless oscillator an implementation is proposed, which preserves energy under finite‐arithmetic conditions. This is verified by comparing simulation results with the analytical solution of a gravity pendulum. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Development of a digital human model generation method for ergonomic design in virtual environment

A group of digital human models (DHMs) representing the target population under consideration is used to design products and workplaces in virtual environment. The present study proposes a two-step method which generates a group of DHMs in various sizes to properly accommodate the designated level of the human size variability of the target population. In the first step, a designated number of pairs of stature and weight within a specified accommodation range are generated from the bivariate normal distribution of stature and weight of the target population. In the second step, for each pair of stature and weight, the sizes of the DHM body segments are determined using hierarchical regression models and corresponding prediction distributions of individual values. The proposed generation method was applied to the 1988 US Army anthropometric survey data and then implemented to a web-based system for passenger car interior design. This web-based generation system is capable of generating a group of DHMs as nationality, gender, accommodation percentage, and the number of DHMs required is specified. Relevance to industry A digital human simulation system has been used as an effective tool for ergonomic design and evaluation of products and workplaces in virtual environment. The human model generation method proposed in the present study is of use to efficiently generate a group of human models representing the target population.

A physics-based digital human model

This paper presents a comprehensive human modelling and simulation environment. This environment, called Santos™, is a new generation of digital human simulation systems that allows a user to interact with a digital character with full and accurate biomechanics and a complete muscular system, subject to the laws of physics. Major results in the areas of dynamic motion prediction, advanced posture prediction and comfort level assessment, physiology model, modelling of clothing and muscle wrapping and force assessment will be presented. This paper will feature the various modules that comprise the Santos environment.

Real-Time Transient Simulation Based on a Robust Two-Layer Network Equivalent

Real-time digital simulation of large power systems requires not only significant computational power but also simpler and accurate models. This paper proposes a new approach for transient simulation of power systems using a robust two-layer network equivalent model and an advanced PC-cluster based parallel real-time simulator. Using a combination of well established fitting and optimization methods, the generated low-order model is of high accuracy compared to its full model over a wide frequency bandwidth. The merits of this method are its robustness in terms of stability and positive-realness, its accuracy at not only transient frequencies but also at dc and power frequency, and its optimal order determination feature. To validate the new method, a realistic large-scale power system - the Alberta interconnected electric system - is simulated in real-time. The real-time electromagnetic transient program is implemented in C++ language using object-oriented programming techniques on the PC-cluster. A time-step of 20 mus has been used for the real-time simulation. The captured oscilloscope results demonstrate excellent accuracy and efficiency of the proposed model in comparison to a full-scale off-line simulation of the original system in the ATP version of EMTP.