A digital twin emulator of a modular production system using a data-driven hybrid modeling and simulation approach

Virtual commissioning is a key technology in Industry 4.0 that can address issues faced by engineers during early design phases. The process of virtual commissioning involves the creation of a Digital Twin—a dynamic, virtual representation of a corresponding physical system. The digital twin model can be used for testing and verifying the control system in a simulated virtual environment to achieve rapid set-up and optimization prior to physical commissioning. Additionally, the modular production control systems, can be integrated and tested during or prior to the construction of the physical system. This paper describes the implementation of a digital twin emulator of an automated mechatronic modular production system that is linked with the running programmable logic controllers and allow for exchanging near real-time information with the physical system. The development and deployment of the digital twin emulator involves a novel hybrid simulation- and data-driven modeling approach that combines Discrete Event Simulation and Agent Based Modeling paradigms. The Digital Twin Emulator can support design decisions, test what-if system configurations, verify and validate the actual behavior of the complete system off-line, test realistic reactions, and provide statistics on the system’s performance.

     

区域多能源系统数字孪生应用平台构建

针对缺乏支撑区域多能源系统数字孪生动态规划、运行优化等上层应用接入、管理和运行的高性能平台的现状,考虑到数字孪生应用对通信效率、数据安全的要求,借助CloudPSS云仿真平台设计了包含基础层、应用层、业务层的安全、灵活、可扩展的数字孪生应用平台的软硬件;并以贵州红枫湖区域多能源系统为试点区域,介绍了包括建模仿真、数据通...     

Improved performance in the multi-unit optimization method with non-identical units

In the multi-unit optimization method, the gradient is estimated using finite difference of the outputs of multiple identical units driven with inputs that are offset by a design parameter. For processes with non-identical units, it is shown that stability is not always guaranteed and that the scheme does not necessarily converge to the desired optimum. Correctors are proposed to compensate for the differences between the units. It is shown that the scheme with correctors is locally asymptotically stable and converges to the respective optimum of each units. The multi-unit optimization method with correctors is applied as an example to bioreactors producing green fluorescent protein.     

基于Transom Jack仿真支持平台的维修仿真系统

随着现代武器装备复杂性的增长,装备维修人员的训练成为一个重要问题.利用虚拟现实技术进行维修培训具有成本低和安全等特点.介绍了利用Transom Jack进行人体建模和维修动作仿真,以及系统的结构设计和具体实现的有关内容,并输出相应的视频文件用于维修培训.     

Virtual-physical digital twin testbed for heterogeneous crowd operations

<正>Heterogeneous crowd operations involve complex procedural subtasks performed by dynamic teams with diverse agent behaviors,tailored to specific task requirements.Examples of such operations include carrier aircraft support,airport ground handling,and logistics transport.Using a hybrid virtual-physical digital twin testbed for scenario generation and plan verification in heterogeneous crowd operations addresses the issues of low credibility in virtual simulations and the high costs associated with real-world testing.It is becoming increasingly important in practical applications.     

Multi-objective ordinal optimization for simulation optimization problems

Ordinal optimization (OO) has been successfully applied to accelerate the simulation optimization process with single objective by quickly narrowing down the search space. In this paper, we extend the OO techniques to address multi-objective simulation optimization problems by using the concept of Pareto optimality. We call this technique the multi-objective OO (MOO). To define the good enough set and the selected set, we introduce two performance indices based on the non-dominance relationship among the designs. Then we derive several lower bounds for the alignment probability under various scenarios by using a Bayesian approach. Numerical experiments show that the lower bounds of the alignment probability are valid when they are used to estimate the size of the selected set as well as the expected alignment level. Though the lower bounds are conservative, they have great practical value in terms of narrowing down the search space.     

Modelling of relative motion in multi-unit mechanical system with limited control

The paper is devoted to the development of a control algorithm to nullify the relative secular drift due to the Earth’s oblateness for the motion of Formation Flying. The chief satellite’s orbit is assumed to be circular and not controlled to maintain the formation. A deputy satellite is equipped with a passive magnetic attitude control system with a permanent magnet and low-propulsion thruster, distributed along the principal inertia axis in the same direction. Research is conducted on the possibility of eliminating the relative secular drift through limited control. The limitation consists in the constraint in the direction and magnitude of feasible control. In the present work, the control to eliminate the relative secular drift is analytically developed. The analytical results are approved by numerical simulation of the satellite motion, such as, of the first Russian nanosatellite TNS-0 No. 1.     

基于CHEMSTAR的在线模拟优化系统

以青岛科技大学计算机与化工研究所的CHEMSTAR化工之星为平台,开发了基于CHEMSTAR的在线模拟优化系统。提出了系统形成的基本思路,建立了系统的总体结构,本系统可以在线的实现过程数据校正和模拟优化。最后,应用工业实例来说明基于CHEMSTAR的在线模拟优化系统的可行性和实用性。     

DeepClassRooms: a deep learning based digital twin framework for on-campus class rooms

Neural Computing and Applications - A lot of different methods are being opted for improving the educational standards through monitoring of the classrooms. The developed world uses Smart...     

SDH数字微波通信系统的分析与仿真

高可信仿真是数字微波领域的有效的预先研究技术途径,通过对SDH微波通信系统进行仿真还能够更多地了解微波系统的规律,有助于解决微波通讯中的关键问题。通过仿真技术的采用,可对在原本微波系统基础上进行高效的特性分析和提升,并可利用仿真设计新的系统,大大降低研制成本和周期,提高工程化效率。本文介绍了SDH微波通信系统的仿真和分析技术及其应用。     

三维仿真数字小区系统的实现

针对房地产行业的特点,运用虚拟现实技术对小区中的建筑物、道路以及室内场景进行三维建模和情景仿真,构建数字化小区系统,把真实的场景模拟出来。系统实现了室外漫游、室内漫游、虚拟装修等功能,为购房者、业主和开发商提供了一个交流的平台。     

Scalable edge enhancement with automatic optimization for digital radiographic images

The ability to resolve fine picture detail is of paramount importance in medical imaging systems for viewing small tissue, bone structure and anatomy in X-ray images. In this paper, we present a new digital radiographic image processing system with the property of scalability and adaptability. (i) A new automatic optimization algorithm is proposed for display. (ii) An adaptive detection of a region-of-interest is developed. (iii) A “scalable edge enhancement algorithm” is proposed to improve the image quality for showing subtle structures in digital radiographic images. The advantage of the proposed method is demonstrated through experiments on 200 digital X-ray images and 50 CT images, in which different parts of human body structures are captured.     

Maintenance models for a continuously degrading system

This paper considers on-condition maintenance of a continuously degrading system, in which the intermaintenance time and the maintenance time depend on the condition of the system at which maintenance is carried out. Without assuming any underlying statistical distribution of the time to failure, models are established to maximize the system average availability when the expected intermaintenance time and the expected maintenance time are (i) deterministic or (ii) contain random components. Optimal solutions on the condition of the system at which maintenance should be performed and the number of times of maintenance action to be carried out are obtained. Numerical searching procedures are proposed, and illustrative examples are given.     

A Newton-like optimization algorithm for digital systems with time delay

The design and computation problems of optimum nonlinear digital time-delay control systems is considered. A minimum principle is presented which solves the design problem, and a second-order computational algorithm is developed which solves the computation problem. The minimum principle is shown to be a special case of a generalized minimum principle in. Hilbert space. The computational algorithm is actually a Newton-like hill-climbing technique for iteratively improving the guessed initial values of the conjugate vector λ so as to satisfy the final condition of the problem. The main advantage of the present algorithm is that it does not require excess memory as in other algorithms.     

A decision support system for paper making based on simulation and optimization

In this paper a model-driven decision support system related to paper making is introduced. The intention is to emphasize the necessity of coupling different modeling techniques, multiobjective optimization, and software engineering in order to make the end user application realistic, practical and usable. Firstly the paper making process and selected aspects concerning its mathematical modeling, numerical simulation, and multiobjective optimization are introduced, then the related computerized system, called a virtual paper making line, is described. In addition, the associated decision support system, which provides a suitable level of automation to improve the quality of decision making and support the user’s expertise is discussed. Finally, an example presents different ways of using such a software tool.     

Fast combinatorial optimization with parallel digital computers

This paper presents an algorithm which realizes fast search for the solutions of combinatorial optimization problems with parallel digital computers. With the standard weight matrices designed for combinatorial optimization, many iterations are required before convergence to a quasioptimal solution even when many digital processors can be used in parallel. By removing the components of the eigenvectors with eminent negative eigenvalues of the weight matrix, the proposed algorithm avoids oscillation and realizes energy reduction under synchronous discrete dynamics, which enables parallel digital computers to obtain quasi-optimal solutions with much less time than the conventional algorithm.     

Architectural optimization of a digital optical multiplier

A computational model of estimation of the time complexity of logical circuits constructed from elements of an optical element base is investigated. A fast parallel multiplier is constructed. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 165–177, September–October 2007.     

MNFP — a new technique for efficient digital fault simulation

Since digital fault simulation is a costly process, it is important to use very efficient techniques to perform this function. To this end, this study suggests that parallel fault simulators couldbe implemented with a new fault-simulation technique, called MNFP (multiple number of faults per pass). The technique intends to partition the total fault set into a number of fault groups which can be simulated as multiple faults. The fault group mentioned above should be structured such that ‘a test that detects any single fault in the group will detect the group, and conversely, a test that detects a group will detect at least one single fault in the group’. Thus, an initial attempt is made to detect a faulty group, then the single faults inside the group are located. During the required fault-partitioning process, such erratic phenomena as fault-masking effects and fictitious multiple-fault generation must be eliminated for the fault groups to have the required property. Two approaches to fault partitioning are made for this technique of fault simulation: PFP (probabilistic fault partitioning) and MFP (modular fault partitioning). Significant savings in simulation time are expected to be realized from the MNFP technique of fault simulation.