Solid State Phenomena Online: 2013-03-11 ISSN: 1662-9779, Vol. 198, pp 606-611 doi:10.4028/www.scientific.net/ssp.198.606 2013 Trans Tech Publications, Switzerland Using CompactRIO to Build a Virtual Driver of Hybrid Wheeled Vehicle Gabriel Kost 1,a, Andrzej Nierychlok 1,b* 1 Silesian University of Technology, Institute Of Engineering Processes Automation And Integrated Manufacturing Systems, Konarskiego 18A, 44-100, Gliwice, Poland a gabriel.kost@polsl.pl, b* andrzej.nierychlok@polsl.pl Keywords: LabVIEW, virtual driver, hybrid vehicle. Abstract. The paper presents the concept of virtual driver of hybrid wheeled vehicle. For this purpose was chosen LabVIEW software and CompactRIO dedicated controller. In the LabVIEW software has been built a mathematical model of a wheeled vehicle taking into account the specific characteristics of engines and torque converter. Wheeled vehicle model has been optimized for metropolitan road conditions where there is frequent braking and acceleration of the wheeled vehicle. For the acceleration of the vehicle in the first phase of motion corresponds to the electric unit, and then at an appropriate speed drive is switched to the internal combustion engine. Using LabVIEW and CompactRIO dedicated controller it is possible to build a virtual controller used for testing hybrid powertrain of a wheeled vehicle in the laboratory. The controller requires an accurate mathematical model to build a wheeled vehicle taking into account the exact characteristics of these two units, external forces acting on wheeled vehicle (resistance movement). The use of virtual driver allows the selection of both powertrain of hybrid wheeled vehicle, to test them as engines working separately or simultaneously with the use of the synergy of energy. Introduction Wheeled vehicles with ICE-electric motors powertrain, have better drive dynamics and higher efficiency than conventional solutions. Important is the choice of driving engines, which optimizes the propulsion system for specific wheeled vehicle. Optimization and design concept in modern machines is described in detail in the following articles [1,2,3,4], which have contributed to deepening the knowledge in the creation of a virtual hybrid powertrain. In addition, the electric motor does not require a clutch, maximum torque is available from minimum speed, so that electric motor can serve as a machine in the first phase of the movement wheeled vehicles and the internal combustion engine running at higher load excreting much smaller amounts of toxic substances into the atmosphere [5,6,7]. Hybrid powertrain can be divided into 3 groups [5,7]: a serial structure (Fig. 1), a parallel structure (Fig. 2), synergy of energy (Fig 3). Serial structure is typically used in vehicles, in which the main driver is an electric motor. Electric engine is used to accelerate and drive the vehicle, while an electric generator is driven by the internal combustion engine which products the electricity required by electric traction motor. The internal combustion engine in this case works in the optimal speed range, for which value the power is optimized for the demand for electricity. Parallel structure is used mainly in vehicles where the main driver can be internal combustion engine or an electric motor. Of course the electric motor could propels the vehicle to the desired line speed, and then the powertrain is switched to the internal combustion engine. The advantage of this approach is direct use of energy from the internal combustion engine to driver a wheeled vehicle, where is no intermediate conversion of energy by drive the generator. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (#69815100, Pennsylvania State University, University Park, USA-18/09/16,15:47:45)
Solid State Phenomena Vol. 198 607 Fig. 1. Serial structure of hybrid powertrain Fig. 2. Parallel structure of hybrid powertrain generator akku / ultra-capacitor ICE electric motor fuel Fig. 3. Synergy of energy structure of hybrid powertrain Synergy of energy is mainly used on wheeled vehicles, where it is possible to driver a vehicle using power from both engines in the same time. Mathematical model A simulation on the hybrid powertrain system was carried out in National Instruments LabVIEW software. In this software, included a mathematical model of the direct current electric motor (DC Motor, Fig. 4, Fig. 5). In the simplest terms, a DC electric motor can be described by the following mathematical equations [6]: torque of electric motor T is expressed as the flow of current in the armature winding and the armature constant of electric machine K T: T = KT i (1)
608 Mechatronic Systems and Materials IV electromotive force (emf) that is expressed as a angle change in the position of the rotor d θ dt (angular velocity) and a constant electric machine K e: dθ e = K (2) dt e Fig. 4. Mathematical model of DC motor Fig. 5. A block diagram of DC motor From Fig. 4, can be written the following equations based on Newton's and Kirchhoff's laws [6]: 2 d θ dθ J + b = K 2 T i (3) dt dt di dθ L + R i = V Ke (4) dt dt where: kg J moment of interia of rotor [ 2 m ], b damping of mechanical system [Nm s] L electric inductance [H], R electric resistance [ Ω], V voltage [V]. From the equations can be written (1-4): Js θ( s) + bsθ( s) = K I( s) (5) T LsI( s) + RI( s) = V( s) Ksθ( s) (6) V( s) Ks e θ( s) I( s) = Ls + R V( s) Ks e θ( s) Js θ( s) + bsθ( s) = KT Ls + R e (7) (8)
Solid State Phenomena Vol. 198 609 LabVIEW model Virtual driver is a control system based on a mathematical model of a wheeled vehicle, including exact mathematical descriptions of hybrid powertrain, like electric and internal combustion engines, hydrokinetic clutch, mechanical gears, electrochemical batteries stored in the LabVIEW software in conjunction with a National Instruments dedicated controller - CompactRIO. The combination of a mathematical model of wheeled vehicle with the control system allows to a very accurate way to simulate the actual behavior of the drive system presented in every vehicle. Advantages of this approach is to adopt a virtual drive system, which possible to optimize the operation of this system in the laboratory in LabVIEW software, before constructing the real-hybrid powertrain system (Fig. 6). Fig. 6. The concept of Virtual Driver The control of a wheeled vehicle by the driver is performed by the steering wheel, accelerator and brake pedals. These tasks in the simulations are implemented through a Logitech steering wheel, where the device has been configured to work in LabVIEW as shown in the block diagram in Fig. 7. LabVIEW simulation Fig. 7. Block diagram of steering wheel The Fig. 8 and Fig. 9 shows the block diagram and front panel of a wheeled vehicle with hybrid powertrain. In Fig. 9 specified the speed of individual engines in RPM and linear velocity of the vehicle. Also presented all the necessary parameters of the propulsion system devices, such as engine torque, the throttle opening angle, the current ratio and gear in the gearbox, current and voltage of the electric motor, and resistance of movement of wheeled vehicle.
610 Mechatronic Systems and Materials IV Fig. 8. Block diagram of hybrid powertrain wheeled vehicle Summary Fig. 9. Front panel of hybrid powertrain wheeled vehicle The concepts of virtual driver of hybrid wheeled vehicle may well serve as a useful tool for research relating to hybrid powertrain in the first phase of design and construction of modern road vehicles. The enormous capabilities of LabVIEW software with a dedicated controller allowed to carrying out computer simulations of wheeled vehicle moving in an urban area and highway streets. Easy to change the parameters of the powertrain system including traction motors allows the simulation stage, the proper selection of the propulsion system for a specific class of wheeled vehicles and their use in urban traffic.
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