Emulation System Research Articles

Emulation of an Electric Naval Propulsion System Based on a Multiphase Machine Under Healthy and Faulty Operating Conditions

The main objective of this paper is the design of an Electric Naval Propulsion System (ENPS) emulator based on a low power multiphase machine. The whole drive system (control, power electronics, and electric machine) is tested and the mechanical part is emulated based on a Hardware-in-the-Loop principle. First, the modeling of all system components including mechanical and electrical parts are reviewed, and the total hull resistance forces are also developed. Then, a pure software simulation of the ENPS is carried out. After that, the designed emulator architecture is presented, and for adaption purpose, a scaling factor is introduced. The developed emulation tool allows to validate optimal control strategies for the propulsion system under a realistic navigation cycle under healthy and faulty operating conditions. Finally, simulation and experimental results are compared to investigate the accuracy and the performance of the developed emulator, and the effectiveness of the proposed control strategies.

Towards the Emulation of the Cardiac Conduction System for Pacemaker Validation

The heart is a vital organ that relies on the orchestrated propagation of electrical stimuli to coordinate each heartbeat. Abnormalities in the heart’s electrical behaviour can be managed with a cardiac pacemaker. Recently, the closed-loop testing of pacemakers with an emulation (real-time simulation) of the heart has been proposed. This enables developers to interrogate their pacemaker design without having to engage in costly or lengthy clinical trials. Many high-fidelity heart models have been developed, but are too computationally intensive to be simulated in real-time. Heart models, designed specifically for the closed-loop testing of pacemaker logic, are too abstract to be useful for the testing of pacemaker implementations. In the context of pacemaker testing, compared to high-fidelity heart models, this article presents a more computationally efficient heart model that generates realistic piecewise continuous electrical signals. The heart model is composed of cardiac cells that are connected by paths. Our heart model is based on the Stony Brook cardiac cell model and the UPenn path model, and improves them by stabilising the activation behaviour of the cells and by capturing the piecewise continuous behaviour of electrical propagation. We provide simulation results that show our ability to faithfully model a range of arrhythmias, such as VA conduction, heart blocks, and long Q-T syndrome. Moreover, re-entrant circuits (that cause arrhythmia) can be faithfully modelled, which only the discrete-event UPenn heart model is also able to achieve.

Parallel genetic algorithm with a knowledge base for a redundancy allocation problem considering the sequence of heterogeneous components

This article presents a new version of the redundancy allocation problem with mixed components (RAPMC) considering the component sequence because it severely affects the reliability of a standby redundant system. It provides a system configuration with exceedingly higher reliability than existing RAPs under same constraints. However, its solution space is significantly expanded according to the number of candidate types and the scale of the system, and thus this study proposed a parallel genetic algorithm with a knowledge base (PGAKB) to efficiently solve it. It includes two strategies, which are the emulation of an expert system and the cooperation between GAs. An individual of the PGAKB creates and exploits the knowledge of the society, and the accumulated knowledge is used for the local search, the final stage for the PGAKB. In conclusion, for solving a complex optimization problem, the PGAKB operates in the form of an expert system and describes a society developing itself by accumulating knowledge. Furthermore, regarding the quality and robustness of solutions and computational time, the effectiveness of the PGAKB was analytically demonstrated by experiments on a famous example.

Cost-efficient FPGA implementation of a biologically plausible dopamine neural network and its application

Abstract Dopamine neurons play an essential role in terms of cognitive coordination and executive functions, which has been investigated in the therapy of multiple psychiatric and neurodegenerative disorders, such as schizophrenia and Parkinson's disease (PD). This paper first explores a series of efficient methods for the hardware implementation of dopamine neuron model aiming to reproduce relevant biological behaviours. In addition, a modified dopamine neuron model based on piecewise linearisation is presented for efficient realisation to reduce the hardware overhead of the original dopamine model and improve the feasibility of the digital design, which is significant for the large-scale network emulation of dopamine system. The accuracy of hardware implementation is validated in terms of dynamical behaviours and bifurcation analyses, and the simulation results including ion channel properties and compensation effect of N-methyl-D-aspartate (NMDA) and γ-Aminobutyric acid (GABA) activation, coincide with the biological dopamine neuron model with a high accuracy. Hardware synthesis and physical implementation on Field Programmable Gate Array (FPGA) illustrate that the proposed model has reliable performance and lower hardware costs compared to original model. These investigations are conducive to construct large FPGA-based network to explore the neurophysiological mechanisms of dopamine system.

Scalability analysis on the smart grid fast automated demand response aggregation Web services for widely distributed building facilities

AbstractIn this paper, we modeled an aggregation communication server of the Fast Automated Demand Response (FastADR) system using an M/M/1 queuing system. Assuming that a very large number of FastADR participating BEMS gateways are widely distributed, scalability of aggregation communication performance was estimated by the M/M/1 transient analysis. Validity of our analysis model was confirmed by realistic wide‐area communication emulation system in the laboratory. Our scalability analysis has shown that at least parallel 25 aggregation systems will be necessary to realize expected communication time of approximately 30 s for an example of FastADR aggregation of 100 MW reduced demand.

An innovative real-time test setup for ADAS’s based on vehicle cameras

The development of Active Safety Systems in Automotive, i.e. functions aimed to reduce the probability of accidents rather than reducing their damages, is represented by Advanced Driver Assistance Systems (ADAS’s). This paper aims to describe an innovative, efficient, safe and economical setup to perform functional tests on ADAS’s whose functions are based on cameras such as Lane Departure Warning (LDW) and Adaptive Cruise Control (ACC). ADAS’s are usually distributed between many Electronics Control Units (ECUs). The system consists of a static Vehicle Test Bench with the real wiring harness and ECUs of the car, connected with a dynamic Hardware in The Loop (HIL) simulator. The HIL simulator is a merger of different ones usually used to test the ECUs on the car, e.g. the Engine Control Module (ECM), the Brake System Module (BSM), the Transmission Control Module (TCM) (for automatic transmission cars), by means of proper simulation models (vehicle dynamic, engine, transmission models). A monitor showing the vehicle scenario to the camera of the car and a proper target emulator system for the radar, whose variable are generated by the vehicle dynamic model, complete the system. Namely, a HIL based Vehicle Test Bench for ADAS functional validation has been made.

Emulation of a Permanent-Magnet Synchronous Generator in Real-Time Using Power Hardware-in-the-Loop

Permanent-magnet synchronous generators (PMSGs) are used in several applications of traction electrification such as power supplies for auxiliary systems and vehicle on-board range-extenders. In this paper, a PMSG is emulated using power hardware in-the-loop. This emulation scheme provides a method to eliminate risks and costs associated with the testing, prototyping, and validation of controllers for power converters and other parts of the traction system. The proposed scheme can be used for testing of motor drives’ different parameters, thereby enabling the testing of a variety of electrical machine drives where the machine prototype is unavailable. The voltage output of the proposed emulator system replicates the voltage generated within the real-time model. The terminal voltage from the real-time model depends on the load connected to the emulator terminals; the current drawn from the emulator output terminals is sensed and fed back to enable the emulator to replicate the PMSG characteristics in steady state and transients. The performance of the system for nonlinear loads, such as a rectifier with a capacitor filter and transient conditions, is also experimentally verified and presented along with validation against a physical PMSG coupled to a dynamometer.

Method using in vivo quantitative spectroscopy to guide design and optimization of low-cost, compact clinical imaging devices: emulation and evaluation of multispectral imaging systems.

.With recent proliferation in compact and/or low-cost clinical multispectral imaging approaches and commercially available components, questions remain whether they adequately capture the requisite spectral content of their applications. We present a method to emulate the spectral range and resolution of a variety of multispectral imagers, based on in-vivo data acquired from spatial frequency domain spectroscopy (SFDS). This approach simulates spectral responses over 400 to 1100 nm. Comparing emulated data with full SFDS spectra of in-vivo tissue affords the opportunity to evaluate whether the sparse spectral content of these imagers can (1) account for all sources of optical contrast present (completeness) and (2) robustly separate and quantify sources of optical contrast (crosstalk). We validate the approach over a range of tissue-simulating phantoms, comparing the SFDS-based emulated spectra against measurements from an independently characterized multispectral imager. Emulated results match the imager across all phantoms ( absorption, reduced scattering). In-vivo test cases (burn wounds and photoaging) illustrate how SFDS can be used to evaluate different multispectral imagers. This approach provides an in-vivo measurement method to evaluate the performance of multispectral imagers specific to their targeted clinical applications and can assist in the design and optimization of new spectral imaging devices.

MEMS Emulator: A Tool for Development and Testing of Electronics for Microelectromechanical Systems

The paper presents the first tool for the emulation of microelectromechanical systems (MEMSs) to be used for the characterization of electronics designed for MEMS. With such a tool, electronics of different nature (integrated, discrete-component, and instrumentation) can be tested (debugged) as in operation, even in the absence of physically available MEMS transducers. The proposed MEMS emulator (MEMU) was implemented through a field-programmable gate array (FPGA) core that synthesized the MEMS transfer function, and through interfaces to the analog electronics under test (ADC to sense signals generated by the electronics, and DAC to provide the emulated MEMS output signal). The parallelism and programmability offered by the FPGA implementation allowed to synthesize several second-order effects of MEMS (noise, spurious modes, feedthrough capacitance, and so on) and to cover a wide range of selectable MEMS parameters. A first prototype of MEMU was developed and experimented. Various MEMS operating up to 25 kHz, with quality factors in the 10−1–10−6 range, were successfully emulated with associated non-idealities. Furthermore, the test of a printed circuit electronic board for piezoresistive MEMS resonators coupled to MEMU to realize a MEMU-based oscillator was shown as a paradigmatic example of the debugging of electronics for MEMS transducers. [2017-0219]

Scalable Light-Weight Integration of FPGA Based Accelerators with Chip Multi-Processors

Modern multicore systems are migrating from homogeneous systems to heterogeneous systems with accelerator-based computing in order to overcome the barriers of performance and power walls. In this trend, FPGA-based accelerators are becoming increasingly attractive, due to their excellent flexibility and low design cost. In this paper, we propose the architectural support for efficient interfacing between FPGA-based multi-accelerators and chip-multiprocessors (CMPs) connected through the network-on-chip (NoC). Distributed packet receivers and hierarchical packet senders are designed to maintain scalability and reduce the critical path delay under a heavy task load. A dedicated accelerator chaining mechanism is also proposed to facilitate intra-FPGA data reuse among accelerators to circumvent prohibitive communication overhead between the FPGA and processors. In order to evaluate the proposed architecture, a complete system emulation with programmability support is performed using FPGA prototyping. Experimental results demonstrate that the proposed architecture has high-performance, and is light-weight and scalable in characteristics.

Wind turbine emulation using permanent magnet synchronous motor

In wind energy conversion systems (WECS), the turbine captures part of the wind energy and converses it to mechanical energy through a dynamic interaction with the electrical generator which in turn converts this mechanical energy to electrical energy. Therefore, the dynamics of the wind turbine is very important in research and development of the overall WECS. Having a real wind turbine or a site with convenient wind conditions is not always a guaranteed option for conducting research. Hence, it is very desirable to create wind turbine dynamics through wind turbine emulation. In this paper, a wind turbine emulation system using a permanent magnet synchronous motor (PMSM) is designed, simulated, implemented, and tested experimentally. The PMSM is torque-controlled using field orientation technique. A three-phase IGBT inverter with closed loop current PI-controllers is used to drive the PMSM. A dSPACE DS1104 DSP prototyping platform is used to handle the real-time execution of the control programs. The system is tested and the torque-speed characteristics of the emulated wind turbine are verified experimentally at different feeds of wind speeds and generator loads.

Sampled data control of non-linear systems using extended order high gain observer

This paper explores alternative design approaches for sampled data extended order observer. After a brief and necessary review of continuous time Extended order High gain observer (EHGO), two alternative sampled data control approaches are being examined, i.e. approximate discrete equivalent system model and emulation. Extended order observer (EHGO) is designed using both aforementioned techniques. Performance of sampled data extended order observer is analysed by using it in a close loop for above mention approaches.

Converter-based reconfigurable real-time electrical system emulation platform

A Hardware Testbed(HTB) is developed for accurate and flexible emulation and testing of electrical power system and their control, measurement, and protection systems. In the HTB, modular and programmable power electronics converters are used to mimic the static and dynamic characteristics of electrical power components. This paper overviews the development, integration, and application of the HTB, covering emulation principle, hardware and software configuration, and example results of power system research using the HTB. The advantages of the HTB, compared with real-time digital simulation and downscaled hardware-based testing platform are discussed.

Software-Driven Definition of Virtual Testbeds to Validate Emergent Network Technologies

The lack of privileged access to emergent and operational deployments is one of the key matters during validation and testing of novel telecommunication systems and technologies. This matter jeopardizes the repeatability of experiments, which results in burdens for innovation and research in these areas. In this light, we present a method and architecture to make the software-driven definition of virtual testbeds easier. As distinguishing features, our proposal can mimic operational deployments by using high-dimensional activity patterns. These activity patterns shape the effect of a control module that triggers agents for the generation of network traffic. This solution exploits the capabilities of network emulation and virtualization systems, which nowadays can be easily deployed in commodity servers. With this, we accomplish a reproducible definition of realistic experimental conditions and the introduction of real agent implementations in a cost-effective fashion. We evaluate our solution in a case study that is comprised of the validation of a network-monitoring tool for Voice over IP (VoIP) deployments. Our experimental results support the viability of the method and illustrate how this formulation can improve the experimentation in emergent technologies.

A novel spatiotemporal home heating controller design: System emulation and field testing

We have developed a spatiotemporal heating control algorithm for use in homes. This system utilises a combination of relatively low-tech hardware interfaced with electric heating systems and a smartphone interface to this hardware, and a central server that progressively learns users' room-specific presence profiles and thermal preferences. This paper describes the associated spatiotemporal heating control algorithm, its evaluation utilising the dynamic building performance simulation software EnergyPlus, and a longitudinal deployment of the algorithm controlling a quasi-autonomous spatiotemporal home heating system in three domestic homes. In this we focus on the prediction of occupants' presence and preferred set-point temperature as well as on the calculation of optimum start time and the utilisation of user-scheduled absences; this for two comfort strategies: to maximise comfort and to minimise discomfort. The former aims to deliver conditions equating to a ‘neutral’ thermal sensation, whereas the latter targets a ‘slightly cool’ sensation with corresponding heating energy savings. Simulation results confirmed that the algorithm functions as intended and that it is capable of reducing energy demand by a factor of seven compared with EnergyStar recommended settings for programmable thermostats. Field study results align with these findings and highlight the possibility to reduce energy under the minimise discomfort strategy without compromising on occupants' thermal comfort.

Migration of Virtual Machine to improve the Security of Cloud Computing

Cloud services help individuals and organization to use data that are managed by third parties or another person at remote locations. With the increase in the development of cloud computing environment, the security has become the major concern that has been raised more consistently in order to move data and applications to the cloud as individuals do not trust the third party cloud computing providers with their private and most sensitive data and information. This paper presents, the migration of virtual machine to improve the security in cloud computing. Virtual machine (VM) is an emulation of a particular computer system. In cloud computing, virtual machine migration is a useful tool for migrating operating system instances across multiple physical machines. It is used to load balancing, fault management, low-level system maintenance and reduce energy consumption. Virtual machine (VM) migration is a powerful management technique that gives data center operators the ability to adapt the placement of VMs in order to better satisfy performance objectives, improve resource utilization and communication locality, achieve fault tolerance, reduce energy consumption, and facilitate system maintenance activities. In the migration based security approach, proposed the placement of VMs can make enormous difference in terms of security levels. On the bases of survivability analysis of VMs and Discrete Time Markov Chain (DTMC) analysis, we design an algorithm that generates a secure placement arrangement that the guest VMs can moves before succeeds the attack.

Composition and Operation of a Semi-Virtual Renewable Energy-based Building Emulator

This paper describes the composition and operation of a semi-virtual energy system and building emulator designed for studying hybrid grid interactions of a modern nearly-zero energy building. The system consists of a real part for energy production (PV panels and micro-wind turbine), storage (batteries and hot water storage tanks) and conversion (ground-source heat pump GSHP and electric heater) combined with a virtual part that models a single-family house in the computer simulation program TRNSYS. A Labview program is used for communication between the real and virtual parts. Measurement data from six periods selected for study between September 2015 and February 2016 are analyzed. The data indicate that during the study, the total electricity consumption was 1290 kWh, divided to 44/38/18% between household appliances, GSHP and electric heater, respectively. The local net production was 250 kWh, or 19% of the total demand. PV, which was heavily concentrated in fall, accounted for 54% of the production. Wind production was winter-centered. The electrical energy matching aspects of the system are represented with two indices: OEFe (on-site electrical energy fraction), the fraction of the building electrical demand covered by local production, and OEMe (on-site electrical energy matching), the ratio of the building’s self-consumption to the total local production. The matching capability of the energy system was found poor due to daily and seasonal mismatches between production and demand. The small net production compared to demand led to small OEFe and large OEMe values overall.

Hardware‐in‐the‐loop real‐time platform for more electric aircraft

Real-time test platform based on hardware-in-the-loop (HIL) simulation technology, troubleshooting for real-time problems such as interrupt latency and interface communication before physical testing, can effectively improve the traditional development process, shorten the research and development cycle, and reduce the cost and risk of test. Based on the technologies of virtual instrument, mathematical modelling, and HIL simulation, a real-time simulation framework combining the discrete-time converter system and the continuous-time motor system is proposed. Combined MATLAB/Simulink, dSPACE, and real-time hardware, an HIL real-time test platform is designed for the prototype and proper testing of the electrical control unit of more electric aircraft. The results and design principles of a three-stage brushless synchronous starter/generator system emulation using HIL simulation are presented.

A Virtual Commissioning Learning Platform

The introduction of reconfigurable manufacturing systems (RMS), Industry 4.0 and the associated technologies requires the establishment of new competencies. Towards that goal, Aalborg University (AAU) has developed an Industry 4.0 learning factory, the AAU Smart Production Lab. The AAU Smart Production Lab integrates a number of Industry 4.0 technologies for learning and research purposes. One of the many techniques is virtual commissioning. Virtual commissioning uses a virtual plant model and real controllers (PLCs) enabling a full emulation of the manufacturing system for verification. Virtual commissioning can lower the commissioning time up to 63%, allowing faster time to market. However, virtual commission is still missing industrial impact one of the reasons being lack of competencies and integration experiences. The paper presents the setup of the virtual commissioning learning platform and demonstrates how various students have worked with the platform acquiring knowledge in virtual commissioning. The construction of a virtual commissioning learning platform enabled a well-defined setup to support training of researchers, students, and companies.

Duality of Complex Systems Built from Higher‐Order Elements

The duality of nonlinear systems built from higher‐order two‐terminal Chua’s elements and independent voltage and current sources is analyzed. Two different approaches are now being generalized for circuits with higher‐order elements: the classical duality principle, hitherto restricted to circuits built from R‐C‐L elements, and Chua’s duality of memristive circuits. The so‐called storeyed structure of fundamental elements is used as an integrating platform of both approaches. It is shown that the combination of associated flip‐type and shift‐type transformations of the circuit elements can generate dual networks with interesting features. The regularities of the duality can be used for modeling, hardware emulation, or synthesis of systems built from elements that are not commonly available, such as memristors, via classical dual elements.