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| 3. |
- Borg, Johan, et al.
(författare)
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Projekt: ESIS
- 2010
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Annan publikation (populärvet., debatt m.m.)abstract
- Samlingsprojekt för alla ESIS-projekt
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| 4. |
- Delsing, Jerker, et al.
(författare)
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The IP-meter, design concept and example implementation of an Internet enabled power line quality meter
- 2000
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Ingår i: Smart connectivity: integrating measurement and control. - Piscataway, NJ : IEEE Communications Society. - 0780358902 ; , s. 657-660
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Konferensbidrag (refereegranskat)abstract
- An Internet Protocol enabled meter, IP-meter, has been designed. As an example of the IP-meter a power line quality meter fully accessible over the Internet has been implemented. The meter is capable of measuring line frequency harmonics with spectral information, transients, line voltage RMS with sags and swells analysis. The Internet access for this application is made over a thin Ethernet medium. The Internet connection is made with a three part design concept: sensor part, microprocessor part and communication part. Served by the built in Webserver the meter is fully accessible via a standard internet browser. Meter setup, data display etc. are made using html pages and Java applets.
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| 5. |
- Enohnyaket, Mathias, et al.
(författare)
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Characteristic signature of electromagnetic emissions from power converters
- 2009
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Ingår i: 2009 IEEE Vehicle Power and Propulsion Conference. - Piscataway, NJ : IEEE Communications Society. - 9781424426003 ; , s. 1036-1042
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Konferensbidrag (refereegranskat)abstract
- Switching operations in power converters controlling electric machines in a hybrid drive train constitute a major source of electromagnetic related disturbances. The emissions from power converters seem to have a characteristic pattern or signature and can be picked up at different locations in the vehicle. This study aims at investigating the signature of emissions from power converters using an H-bridge driving a dc motor. PSpice model of the motor and drive circuit was made and current, voltage, and field measurements were performed on a constructed prototype. Current transients and oscillations generated during voltage transitions have been investigated using the PSpice model. A correlation between the common mode currents and the magnetic field emissions was observed.
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| 6. |
- Enohnyaket, Mathias, et al.
(författare)
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Parameter characterization of low frequency pulsating emissions from space vector PWM drives
- 2011
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Ingår i: Proceedings of 2010 IEEE Vehicle Power and Propulsion Conference, VPPC 2010. - Piscataway, NJ : IEEE Communications Society. - 9781424482207
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Konferensbidrag (refereegranskat)abstract
- Power converters in hybrid electric drives constitute a major source of electromagnetic disturbances. Recent studies have established that the space vector PWM scheme commonly employed in drive systems, generates low frequency pulsating (LFP) emissions, at a frequency of 6f0, where f0 is the fundamental frequency the phase voltages. The switching of voltage vectors generates common mode current (icm) spikes due to the presence of stray capacitances and inductances. Across sector boundaries, the icm spikes superpose forming spikes of double or tipple amplitude which constitute the LFP emissions. These pulsating emissions could pose EMC issues, and functionality issues like torque pulsations and speed fluctuations that could affect the reliability of the drive. This paper investigates the effects of drive speed, load, and converter slew rates, on the amplitude of the LFP emissions, using theoretical models.
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| 7. |
- Fredriksson, Håkan, et al.
(författare)
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GIMnet on the MICA wheelchair
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper describes the implementation of GIMnet on the MICA wheelchair.
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| 8. |
- Fredriksson, Håkan, et al.
(författare)
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Gyro feedback of a hydraulic steering system
- 2011
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Ingår i: International Journal of Vehicle Autonomous Systems. - 1471-0226 .- 1741-5306. ; 9:3/4, s. 189-202
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Tidskriftsartikel (refereegranskat)abstract
- We study the problem to steer, teleoperated as well as autonomously, a tractor that is to operate on a rough and slippery surface. The main idea is to control the effective steering angle of the vehicle. A benefit with this approach is that the vehicle will strive to move in a predefined way irrespective of the surface conditions. To test if the approach is usable we implemented a straight forward p-controller in combination with an estimator of the effective steering angle of the tractor. Our tests indicates that the approach can be useful. Future work would include studies on more advanced control strategies and estimators to reduce some of the problems that we address.
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| 9. |
- Fredriksson, Håkan, et al.
(författare)
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Multisource flash system for retroreflective beacon detection in CMOS cameras
- 2008
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Ingår i: Optical Engineering. - : SPIE-Intl Soc Optical Eng. - 0091-3286 .- 1560-2303. ; 47, s. 103001-
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Tidskriftsartikel (refereegranskat)abstract
- We present a method for improving a flash system for retroreflective beacon detection in CMOS cameras. Generally, flash systems are designed in such a manner that makes them suited for beacon detection in a small range interval. We strive to increase the flash system range interval by exploiting the directional properties of the retroreflector. Thus, light sources placed relatively far away from the optical axis of the camera will contribute only when the retroreflector is far away. This fact can be used to compensate for the 1/distance2 dependency of optical power. We present underlying theory and formulae, then describe a flash system consisting of several light-emitting diodes that was designed by considering the presented method. Simulations show that the usable flash range of the improved system can be almost doubled compared to a general flash system. Tests were performed indicating that the presented method works according to theory and simulations.
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| 10. |
- Fredriksson, Håkan, et al.
(författare)
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Range data in vehicle dynamic simulation
- 2009
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Konferensbidrag (refereegranskat)abstract
- This paper presents a way to merge range data into the vehicle dynamic simulation software CarSim7.1. The range data consists of measurements describing the surface of a road, and thus, creates a close to reallife 3D simulation environment. This reduces the discrepancy between the real life tests and simulation ofvehicle suspension systems, dampers, springs, etc. It is important for the vehicle industry to represent a reallife environment in the simulation software in order to increase the validity of the simulations and to studythe effects that uneven roads have on the systems. Furthermore, a 3D environment based on real life data isalso useful in driving simulators, when for example, analysing driver behaviour, testing driver response, andtraining for various driving conditions. To measure and collect data, a car was equipped with instruments anda computer. On top of the car, a SICK LMS200 2D lidar was mounted tilted downwards, facing the roadin front of the car. To create the 3D environment, all the individual measurements were transformed to aglobal coordinate system using the pose (position and orientation) information from a high-class navigationsystem. The pose information made it possible to compensate for the vehicle motion during data collection.The navigation system consisted of a GPS/IMU system from NovAtel. To reach high navigation performance,the raw GPS/IMU data were post-processed and fused with data from three different fixed GPS base stations.The range data were modified with a Matlab script in order to parse the data into a file that could be read byCarSim software. This created the 3D road used in the vehicle dynamic simulations. The measurements werecollected at a go-kart track in Lule°a, Sweden. Finally, tests have been performed to compare simulation resultsbetween using a 2D surface (i.e. flat) and a 3D surface (close to real life). It is seen that the simulation resultsusing the 2D surface is clearly different from the 3D surface simulation.
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