• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 81
  • 16
  • 10
  • 10
  • 10
  • 4
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 171
  • 171
  • 70
  • 53
  • 52
  • 34
  • 33
  • 33
  • 26
  • 25
  • 23
  • 21
  • 19
  • 19
  • 19
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Hardware in the Loop Simulation of a Heavy Truck Braking System and Vehicle Control System Design

Ashby, Ryan Michael 09 August 2013 (has links)
No description available.
102

Hardware-supported test environment analysis for CAN message communication

Akaslan, Seyhmus 08 July 2024 (has links)
Recent innovations in technology and demands for more functionality increased software size in cars up to 100 million lines of code. Explosion in software size is accompanied by an increased number of ECUs. Testing of software became more complex than ever. To be able to test the exact timing behavior of a software, it needs to be put on actual hardware. HIL test benches have become an indispensable part of ECU testing. The hard part of ECU testing is their dependency on each other. ECUs communicate to each other by passing information in the form of CAN messages. This makes testing a single ECU alone without its environment impossible. Because of their dependencies on each other they need to be integrated first to be tested. Before HIL benches those tests were done either on vehicles or in integration labs where ECUs are connected to each other in a lab environment. Advances in software science brought up an invention known as rest-bus simulation. In some sources it is also known as residual bus or rest of the bus simulation. HIL platforms simulate missing nodes and messages as if the actual hardware is there. HIL platforms blend the real world and simulated ones in real time. Device under test thinks it is present in a vehicle. Established HIL platforms solved many problems that existed in software projects. However, because of their cost, only a small number of such platforms are affordable within a company. Developers need to wait in long queues to test their ECUs. These waiting times can be even longer in agile software development methodologies due to their frequent testing needs. It is believed that front-loading tests before the HIL is the solution to this problem. The aim of this thesis is to investigate alternative small form factor HIL platforms which could be placed on every developer’s desk. To place the proposed solution at every desk, the solution must be affordable and portable. The solution will hopefully reduce queues accumulating behind established HIL platforms and shorten testing times. For this end, state-of-the-art HIL solutions will be investigated. Afterwards, a working proof-of-concept will be demonstrated in the form of residual bus simulation and gateway application. Portability of the solution is a must for the gateway application. Test engineers use gateway applications to alter some signal values either on HIL or on-vehicle. Only small and easy to carry solutions are feasible for on-vehicle testing. It will be shown that the proposed solution will reduce the testing time and testing cost. In addition to them, an increase in parallelism, testing frequency, and software quality will be observed by bringing testing equipment to every developer’s desk.
103

Multiple Simultaneous Specification Attitude Control of a Mini Flying-wing Unmanned Aerial Vehicle

Markin, Shael 12 January 2011 (has links)
The Multiple Simultaneous Specification controller design method is an elegant means of designing a single controller to satisfy multiple convex closed loop performance specifications. In this thesis, the method is used to design pitch and roll attitude controllers for a Zagi flying-wing unmanned aerial vehicle from Procerus Technologies. A linear model of the aircraft is developed, in which the lateral and longitudinal motions of the aircraft are decoupled. The controllers are designed for this decoupled state space model. Linear simulations are performed in Simulink, and all performance specifications are satisfied by the closed loop system. Nonlinear, hardware-in-the-loop simulations are carried out using the aircraft, on-board computer, and ground station software. Flight tests are also executed to test the performance of the designed controllers. The closed loop aircraft behaviour is generally as expected, however the desired performance specifications are not strictly met in the nonlinear simulations or in the flight tests.
104

Multiple Simultaneous Specification Attitude Control of a Mini Flying-wing Unmanned Aerial Vehicle

Markin, Shael 12 January 2011 (has links)
The Multiple Simultaneous Specification controller design method is an elegant means of designing a single controller to satisfy multiple convex closed loop performance specifications. In this thesis, the method is used to design pitch and roll attitude controllers for a Zagi flying-wing unmanned aerial vehicle from Procerus Technologies. A linear model of the aircraft is developed, in which the lateral and longitudinal motions of the aircraft are decoupled. The controllers are designed for this decoupled state space model. Linear simulations are performed in Simulink, and all performance specifications are satisfied by the closed loop system. Nonlinear, hardware-in-the-loop simulations are carried out using the aircraft, on-board computer, and ground station software. Flight tests are also executed to test the performance of the designed controllers. The closed loop aircraft behaviour is generally as expected, however the desired performance specifications are not strictly met in the nonlinear simulations or in the flight tests.
105

Modeling and real-time optimal energy management for hybrid and plug-in hybrid electric vehicles

Dong, Jian 15 February 2017 (has links)
Today, hybrid electric propulsion technology provides a promising and practical solution for improving vehicle performance, increasing energy efficiency, and reducing harmful emissions, due to the additional flexibility that the technology has provided in the optimal power control and energy management, which are the keys to its success. In this work, a systematic approach for real-time optimal energy management of hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) has been introduced and validated through two HEV/PHEV case studies. Firstly, a new analytical model of the optimal control problem for the Toyota Prius HEV with both offline and real-time solutions was presented and validated through Hardware-in-Loop (HIL) real-time simulation. Secondly, the new online or real-time optimal control algorithm was extended to a multi-regime PHEV by modifying the optimal control objective function and introducing a real-time implementable control algorithm with an adaptive coefficient tuning strategy. A number of practical issues in vehicle control, including drivability, controller integration, etc. are also investigated. The new algorithm was also validated on various driving cycles using both Model-in-Loop (MIL) and HIL environment. This research better utilizes the energy efficiency and emissions reduction potentials of hybrid electric powertrain systems, and forms the foundation for development of the next generation HEVs and PHEVs. / Graduate / laindeece@gmail.com
106

Modelagem e implementação em tempo real de sistema de controle de atitude em três eixos para satélite de baixo custo

Synara Rosa Gomes dos Santos 13 June 2012 (has links)
Satélites artificiais, em sua grande maioria, requerem algum tipo de sistema de controle de atitude (SCA) embarcado. A utilização de simuladores para avaliar este tipo de sistema é uma técnica bastante difundida na _área de engenharia, pois viabiliza a realização de testes de maneira rápida e a um custo menor do que utilizando ambientes com componentes reais. Contudo, de ciências no desenvolvimento de softwares embarcados podem ser difíceis de detectar quando o ambiente de teste não leva em consideração restrições comuns aos ambientes de tempo real. Partindo deste preâmbulo, este trabalho apresenta e analisa a modelagem em UML (Unified Modeling Language) de um sistema de controle de atitude autônomo para satélites estabilizados por rotação, bem como implementação de um ambiente de teste, com base na técnica de simulação hardware-in-the-loop, utilizando um sistema operacional de tempo real para escalonamento das tarefas, e um típico computador de bordo com processador ERC32. Na simulação hardware-in-the-loop o SCA é realimentado por estimativas da atitude em 3 eixos e da velocidade angular do satélite fornecidas pelo sistema de determinação de atitude (SDA). O SDA consiste de um filtro de Kalman estendido (FKE) que processa as medidas vetoriais da direção do Sol e campo geomagnético para gerar as estimativas. Resultados experimentais mostram que o sistema de controle de atitude foi bem-sucedido em regime após uma fase inicial de manobras para aquisição da atitude desejada.
107

Hybrid testing of an aerial refuelling drogue

Bolien, Mario January 2018 (has links)
Hybrid testing is an emerging technique for system emulation that uses a transfer system composed of actuators and sensors to couple physical tests of a critical component or substructure to a numerical simulation of the remainder of a system and its complete operating environment. The realisation of modern real-time hybrid tests for multi-body contact-impact problems often proves infeasible due to (i) hardware with bandwidth limitations and (ii) the unavailability of control schemes that provide satisfactory force and position tracking in the presence of sharp non-linearities or discontinuities. Where this is the case, the possibility of employing a pseudo-dynamic technique remains, enabling tests to be conducted on an enlarged time scale thus relaxing bothbandwidth and response time constraints and providing inherent loop stability. Exploiting the pseudo-dynamic technique, this thesis presents the development of Robotic Pseudo-Dynamic Testing (RPsDT), a dedicated method that specifically targets the realisation of hybrid tests for multi-body contact-impact problems using commercial off- the shelve (COTS) industrial robotic manipulators. The RPsDT method is evaluated in on-ground studies of air-to-air refuelling (AAR) maneuvers with probe-hose-drogue systems where the critical contact and coupling phase is tested pseudo-dynamicallywith full-scale refuelling hardware while the flight regime is emulated in simulation. It is shown that the RPsDT method can faithfully reproduce the dominant contact impact phenomena between probe and drogue while minor discrepancies result from the absence of rate-dependant damping in the force feedback measurements. In combination with full-speed robot controlled contact tests, reliable estimates for impact forces, strain distributions and drogue responses to off-centre hits are obtained providing extensive improvements over current predictive capabilities for the in-flight behaviour of refuelling hardware and it is concluded that the technique shows great promise for industrial applications.
108

Cylinder-by-Cylinder Diesel Engine Modelling : A Torque-based Approach / Cylinderindividuell modellering av en dieselmotor

Ramstedt, Magnus January 2004 (has links)
<p>Continuously throughout the process of developing Engine Control Units (ECU), the ECU and its control functions need to be dimensioned and tested for the engine itself. Since interaction between an ECU and a physical engine is both expensive and inflexible, software models of the engine are often used instead. One such test system, where an ECU interacts with software models, is called Hardware-in-the-Loop (HiL). This thesis describes a model constructed to facilitate implementation on a HiL testbed. </p><p>The model, derived in Matlab/Simulink, is a Cylinder-by-Cylinder Engine Model (CCEM) reconstructing the angle synchronous torque of a diesel engine. To validate the model, it has been parameterised for the DaimlerChrysler engine OM646, a straight turbocharged four cylinder diesel engine, and tested towards measured data from a Mercedes-Benz C220 test vehicle. Due to hardware related problems, validation could only be performed for low engine speeds where the model shows good results. Future work around this theme ought to include further validation of the model as well as implementation on HiL.</p>
109

Cylinder-by-Cylinder Diesel Engine Modelling : A Torque-based Approach / Cylinderindividuell modellering av en dieselmotor

Ramstedt, Magnus January 2004 (has links)
Continuously throughout the process of developing Engine Control Units (ECU), the ECU and its control functions need to be dimensioned and tested for the engine itself. Since interaction between an ECU and a physical engine is both expensive and inflexible, software models of the engine are often used instead. One such test system, where an ECU interacts with software models, is called Hardware-in-the-Loop (HiL). This thesis describes a model constructed to facilitate implementation on a HiL testbed. The model, derived in Matlab/Simulink, is a Cylinder-by-Cylinder Engine Model (CCEM) reconstructing the angle synchronous torque of a diesel engine. To validate the model, it has been parameterised for the DaimlerChrysler engine OM646, a straight turbocharged four cylinder diesel engine, and tested towards measured data from a Mercedes-Benz C220 test vehicle. Due to hardware related problems, validation could only be performed for low engine speeds where the model shows good results. Future work around this theme ought to include further validation of the model as well as implementation on HiL.
110

Hardware Simulation of Fuel Cell / Gas Turbine Hybrids

Smith, Thomas Paul 06 April 2007 (has links)
Hybrid solid oxide fuel cell / gas turbine (SOFC/GT) systems offer high efficiency power generation, but face numerous integration and operability challenges. This dissertation addresses the application of hardware-in-the-loop simulation (HILS) to explore the performance of a solid oxide fuel cell stack and gas turbine when combined into a hybrid system. Specifically, this project entailed developing and demonstrating a methodology for coupling a numerical SOFC subsystem model with a gas turbine that has been modified with supplemental process flow and control paths to mimic a hybrid system. This HILS approach was implemented with the U.S. Department of Energy Hybrid Performance Project (HyPer) located at the National Energy Technology Laboratory. By utilizing HILS the facility provides a cost effective and capable platform for characterizing the response of hybrid systems to dynamic variations in operating conditions. HILS of a hybrid system was accomplished by first interfacing a numerical model with operating gas turbine hardware. The real-time SOFC stack model responds to operating turbine flow conditions in order to predict the level of thermal effluent from the SOFC stack. This simulated level of heating then dynamically sets the turbine's "firing" rate to reflect the stack output heat rate. Second, a high-speed computer system with data acquisition capabilities was integrated with the existing controls and sensors of the turbine facility. In the future, this will allow for the utilization of high-fidelity fuel cell models that infer cell performance parameters while still computing the simulation in real-time. Once the integration of the numeric and the hardware simulation components was completed, HILS experiments were conducted to evaluate hybrid system performance. The testing identified non-intuitive transient responses arising from the large thermal capacitance of the stack that are inherent to hybrid systems. Furthermore, the tests demonstrated the capabilities of HILS as a research tool for investigating the dynamic behavior of SOFC/GT hybrid power generation systems.

Page generated in 0.0596 seconds