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  • 1.
    Ahlmark, Daniel Innala
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Fredriksson, Håkan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Den seende rullstolen2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [sv]

    Den vita käppen har använts av synskadade i snart hundra år. Den är ett intuitivt hjälpmedel med vars hjälp en synskadad person självständigt kan ta sig fram. För rörelsehindrade personer som också är synskadade är denna självständighet inte lika självklar. Om en rullstol eller rollator behövs blir käppen opraktisk, vilket innebär att mänsklig assistans kan bli nödvändig.MICA (Mobile Internet Connected Assistant) är en datoriserad rullstol som utrustats med en laserskanner som, i laserns svep-plan, mäter avstånd till hinder i omgivningen. Denna information har använts för att bland annat få rullstolen att på egen hand ta sig runt hinder, med avsikten att användare som inte har full förmåga att styra en rullstol ändå skall kunna använda den.Med det senaste tillskottet till MICA – en virtuell vit käpp – är tanken att synskadade personer med begränsad rörelseförmåga skall kunna känna sig fram i sin omgivning och därmed navigera självständigt. Detta åstadkoms genom att laserns mätningar av omgivningen genererar en förenklad 3D-modell av omgivningen. Denna modell skickas sedan till en haptisk robot som gör det möjligt för brukaren att känna på det lasern mäter upp, och på så vis upptäcka hinder på samma sätt som med en vanlig käpp.Utvecklingen av den virtuella vita käppen är ännu i sitt inledningsskede. Första offentliga demonstrationen av MICA utrustad med den virtuella käppen, även kallad ”Den seende rullstolen”, skedde 2011-05-10. En kort film om ”The sighted wheelchair” finns nu YouTube. Fortsatt arbete kommer bestå i att vidareutveckla mjukvaran som kommunicerar med lasern och roboten för att få en bättre användarupplevelse, samt att kringgå laserns begränsning att bara mäta i ett plan så att en mer realistisk modell av omgivningen kan byggas upp.

  • 2.
    Ahlmark, Daniel Innala
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Fredriksson, Håkan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Obstacle Avoidance Using Haptics and a Laser Rangefinder2013Ingår i: 2013 IEEE Workshop on Advanced Robotics and its Social Impacts: Tokya, Japan, 7-9 Nov 2013, Piscataway, NJ: IEEE Communications Society, 2013, s. 76-81Konferensbidrag (Refereegranskat)
    Abstract [en]

    In its current form, the white cane has been used by visually impaired people for almost a century. It is one of the most basic yet useful navigation aids, mainly because of its simplicity and intuitive usage. For people who have a motion impairment in addition to a visual one, requiring a wheelchair or a walker, the white cane is impractical, leading to human assistance being a necessity. This paper presents the prototype of a virtual white cane using a laser rangefinder to scan the environment and a haptic interface to present this information to the user. Using the virtual white cane, the user is able to "poke" at obstacles several meters ahead and without physical contact with the obstacle. By using a haptic interface, the interaction is very similar to how a regular white cane is used. This paper also presents the results from an initial field trial conducted with six people with a visual impairment.

  • 3.
    Ahlmark, Daniel Innala
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Presentation of Spatial Information in Navigation Aids for the Visually Impaired2015Ingår i: Journal of Assistive Technologies, ISSN 1754-9450, E-ISSN 2042-8723, Vol. 9, nr 3, s. 174-181Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: The purpose of this article is to present some guidelines on how different means of information presentation can be used when conveying spatial information non-visually. The aim is to further the understanding of the qualities navigation aids for visually impaired individuals should possess.Design/methodology/approach: A background in non-visual spatial perception is provided, and existing commercial and non-commercial navigation aids are examined from a user interaction perspective, based on how individuals with a visual impairment perceive and understand space.Findings: The discussions on non-visual spatial perception and navigation aids lead to some user interaction design suggestions. Originality/value: This paper examines navigation aids from the perspective of non-visual spatial perception. The presented design suggestions can serve as basic guidelines for the design of such solutions.

  • 4.
    Ahlmark, Daniel Innala
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Prellwitz, Maria
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Röding, Jenny
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Nyberg, Lars
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    An Initial Field Trial of a Haptic Navigation System for Persons with a Visual Impairment2015Ingår i: Journal of Assistive Technologies, ISSN 1754-9450, E-ISSN 2042-8723, Vol. 9, nr 4, s. 199-206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose– The purpose of this paper is to describe conceptions of feasibility of a haptic navigation system for persons with a visual impairment (VI). Design/methodology/approach– Six persons with a VI who were white cane users were tasked with traversing a predetermined route in a corridor environment using the haptic navigation system. To see whether white cane experience translated to using the system, the participants received no prior training. The procedures were video-recorded, and the participants were interviewed about their conceptions of using the system. The interviews were analyzed using content analysis, where inductively generated codes that emerged from the data were clustered together and formulated into categories. Findings– The participants quickly figured out how to use the system, and soon adopted their own usage technique. Despite this, locating objects was difficult. The interviews highlighted the desire to be able to feel at a distance, with several scenarios presented to illustrate current problems. The participants noted that their previous white cane experience helped, but that it nevertheless would take a lot of practice to master using this system. The potential for the device to increase security in unfamiliar environments was mentioned. Practical problems with the prototype were also discussed, notably the lack of auditory feedback. Originality/value– One novel aspect of this field trial is the way it was carried out. Prior training was intentionally not provided, which means that the findings reflect immediate user experiences. The findings confirm the value of being able to perceive things beyond the range of the white cane; at the same time, the participants expressed concerns about that ability. Another key feature is that the prototype should be seen as a navigation aid rather than an obstacle avoidance device, despite the interaction similarities with the white cane. As such, the intent is not to replace the white cane as a primary means of detecting obstacles.

  • 5.
    Ahlmark, Daniel Innala
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Prellwitz, Maria
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Röding, Jenny
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Nyberg, Lars
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Virtuell vit käpp för den seende rullstolen2013Konferensbidrag (Övrigt vetenskapligt)
  • 6.
    Ahlmark, Daniel Innala
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hand-held navigation aid for visually impaired using haptic feedback2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The white cane is used by many visually impaired individuals as the primary aid for avoiding obstacles. In this it is unparalleled, but it cannot provide a large-scale view of the surroundings the way vision does. This makes navigating independently a challenge for the visually impaired. We are developing the Virtual White Cane (VWC), a device that uses sensors and haptic technologies to complement the limited view of the cane. Sensors makes it possible to probe obstacles far beyond the range of the white cane, and haptic feedback is familiar to users of the regular cane. The purpose of this device is to act as a complement to the standard cane, providing information about the surroundings that are beyond the cane's reach. This kind of extended view not only helps in anticipating obstacles, but also to navigate. The presentation will focus on the hardware of the currently developed prototype, in addition to some initial user experiences.

  • 7.
    Andersson, Ulf
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Mrozek, Kent
    Åström, Kalle
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Path design and control algorithms for articulated mobile robots1997Ingår i: Proceedings of the International Conference on Field and Service Robotics / [ed] Alexander Zelinsky, 1997, s. 405-411Konferensbidrag (Refereegranskat)
  • 8. Borg, Johan
    et al.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Projekt: ESIS2010Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Samlingsprojekt för alla ESIS-projekt

  • 9.
    Delsing, Jerker
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Isaksson, Thord
    Luleå tekniska universitet.
    The IP-meter, design concept and example implementation of an Internet enabled power line quality meter2000Ingår i: Smart connectivity: integrating measurement and control: proceedings of the 17th IEEE Instrumentation and Measurement Technology Conference, Hilton Hotel and Towers, Baltimore, Maryland, USA, May 1 . 4, 2000, Piscataway, NJ: IEEE Communications Society, 2000, s. 657-660Konferensbidrag (Refereegranskat)
    Abstract [en]

    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.

  • 10. Enohnyaket, Mathias
    et al.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Characteristic signature of electromagnetic emissions from power converters2009Ingår i: 2009 IEEE Vehicle Power and Propulsion Conference: VPPC 2009 ; Dearborn, Michigan, USA, 7 - 11 September 2009, Piscataway, NJ: IEEE Communications Society, 2009, s. 1036-1042Konferensbidrag (Refereegranskat)
    Abstract [en]

    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.

  • 11.
    Enohnyaket, Mathias
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Parameter characterization of low frequency pulsating emissions from space vector PWM drives2011Ingår i: Proceedings of 2010 IEEE Vehicle Power and Propulsion Conference, VPPC 2010: Lille; 1 September 2010 - 3 September 2010, Piscataway, NJ: IEEE Communications Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    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.

  • 12.
    Fredriksson, Håkan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Andersson, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Track loader kinematics2010Ingår i: Preprints: The Second IFAC Symposium on Telematics Applications, TA 2010, Timi¸soara, Romania, 5 - 8 October 2010 / [ed] Ioan Dumitrache, Timisoara: Ed. Politehnica , 2010, s. 139-142Konferensbidrag (Refereegranskat)
    Abstract [en]

    We study the problem to teleoperate a Caterpillar 973c track loader. The track loader and a system for teleoperation are described. A tested and working kinematic model used for dead reckoning is also presented. Track speed sensors combined with a rate gyro are used as input to the model. The model shows good results when tested and compared to a GPS navigation system.

  • 13.
    Fredriksson, Håkan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Danielsson, Peter
    Student LTU.
    Rönnbäck, Sven
    Hyyppä, Kalevi
    snowBOTs: Gyro guided steering of a teleoperated tractor during winter conditions2008Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This article describes the steering system implemented on the tractor IceMaker I. No direct position feedback is used for the steering angle of the front wheels. Instead, the steering angle is estimated by a motion model of the vehicle using gyro and odometer information. This estimated angle is used as feedback to a regulator that controls the steering system. The operator sets the requested steering angle and the regulator controls the hydraulic steering system to maintain the requested steering angle. Within certain limits, the tractor can be expected to behave according to the motion model irrespective of the surface conditions. The tractor can be teleoperated from a remote computer through a wireless network, WLAN. To enable teleoperation, the tractor has been equipped with a computer, some sensors, and other necessary equipment. During teleoperation, the operator controls the steering angle of the front wheels and the speed of the tractor using a joystick. The steering system has been tested both during winter conditions on a low friction surface and also on dry asphalt. The results indicates good performance when teleoperating the tractor. When driving carefully it is possible to operate the tractor up to full speed (25km/h). However, the steering regulator tends to exaggerate the real steering angle during sharp turns when driving on very slippery surface.

  • 14. Fredriksson, Håkan
    et al.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    GIMnet on the MICA wheelchair2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This paper describes the implementation of GIMnet on the MICA wheelchair.

  • 15.
    Fredriksson, Håkan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Multisource flash system for retroreflective beacon detection in CMOS cameras2008Ingår i: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 47, s. 103001-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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.

  • 16.
    Fredriksson, Håkan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Andersson, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Gyro feedback of a hydraulic steering system2011Ingår i: International Journal of Vehicle Autonomous Systems, ISSN 1471-0226, E-ISSN 1741-5306, Vol. 9, nr 3/4, s. 189-202Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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.

  • 17. Fredriksson, Håkan
    et al.
    Rönnbäck, Sven
    Berglund, Tomas
    Wernersson, Åke
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    snowBOTS: a mobile robot on snow covered ice2007Ingår i: Proceedings of the 13th IASTED International Conference on Robotics and Applications: August 29 - 31, 2007, Würzburg, Germany / [ed] K. Schilling, Anaheim, Calif.: ACTA Press, 2007, s. 222-228Konferensbidrag (Refereegranskat)
    Abstract [en]

    We introduce snowBOTs as a generic name for robots working in snow. This paper is a study on using scan ning range measuring lasers towards an autonomous snow cleaning robot, working in an environment consisting al most entirely of snow and ice. The problem addressed here is using lasers for detecting the edges generated by "the snow meeting the road". First the laser data were filtered using his togram/median to discriminate against falling snowflakes and small objects. Then the road surface was extracted us ing the range weighted Hough/Radon transform. Finally the left and right edges of the road was detected by thresh olding. Tests have been made with a laser on top of a car driven in an automobile test range just south of the Arctic Circle. Moreover, in the campus area, the algorithms were tested in closed loop with the laser on board a robotized wheelchair.

  • 18.
    Hakapää, Liisa
    et al.
    Lapin yliopisto, PL 122, 96101 ROVANIEMI.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Rönnbäck, Sven
    Kamunen, Veikko
    Lapin yliopisto, PL 122, 96101 ROVANIEMI.
    Koskinen, Simo
    Lapin yliopisto, PL 122, 96101 ROVANIEMI.
    Piekkari, Jouni
    Lapin yliopisto, PL 122, 96101 ROVANIEMI.
    MICA - Mobile Internet Connected Assistant2005Ingår i: First International Conference on Lifestyle, Health and Technology: June 1-3, 2005 at Luleå University of Technology, Porsön, Luleå, Sweden, Luleå: Luleå tekniska universitet, 2005Konferensbidrag (Refereegranskat)
  • 19.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A low-noise photodiode-amplifier circuit1993Rapport (Övrigt vetenskapligt)
  • 20.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Competition - an efficient method to get students committed2004Ingår i: Proceedings: IEEE International Conference on Advanced Learning Technologies : 30 August - 1 September 2004, Joensuu, Finland (ICALT), Los Alamitos, Calif: IEEE Communications Society, 2004, s. 211-215Konferensbidrag (Refereegranskat)
    Abstract [en]

    The mechatronics course at Lulea University of Technology is divided into a traditional part with lectures, problem solving, lab exercises, and a project part. During 2002-2003, the project has been to design and build autonomous model race cars. A public race is arranged at the end of the course. The race track is an outdoor track. In year 2002, it was defined by a painted white line on asphalt. In 2003, it was defined by an electrical wire carrying 100 mA of current at 10 kHz frequency. The students had to design and build sensors, amplifiers, filters and interface circuits for the onboard PICI6F876 microcontroller as well as some power electronics to control the drive DC-motor. The race is obviously extremely challenging for the students and as a result, they spend much more time on the course than before.

  • 21.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Design considerations in a laser navigation system for mobile robots1994Ingår i: Mechatronics (Oxford), ISSN 0957-4158, E-ISSN 1873-4006, Vol. 4, nr 2, s. 199-206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A navigation system for mobile robots is discussed. The system utilizes a laser anglemeter which measures heading angles to beacons made of retroreflective tape. It is shown that the motion restrictions of a typical mobile robot can be utilized to simplify the angle measurement task considerably. Beam properties of typical HeNe-lasers and collimated GaAs-laser diodes are discussed. The collimated GaAs-laser is shown to be superior for the anglemeter. A design rule is given for the anglemeter receiver optics. Noise sources in the anglemeter receiver are discussed. Reference is made to a new low-noise photodiode-amplifier circuit which has the photodiode in the feedback path.

  • 22. Hyyppä, Kalevi
    Dielectric absorption in memory capacitors1972Ingår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. IM-21, nr 1, s. 53-56Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Experience from experiments with a sample and hold circuit showed that dielectric absorption constitutes a fundamental limitation of the accuracy in analog memories. To gain more insight into the problem several materials commonly used as dielectrics in capacitors have been investigated. The theory of dielectric absorption is discussed. Results from measurements on capacitors with paper, cellulose acetate, parylene, polyester, polycarbonate, and polystyrene dielectrics are reported. The components in Dow's model, which describes the dielectric absorption, are calculated for the polycarbonate dielectric. A compensation circuit is suggested, which considerably reduces the effect of dielectric absorption in analog memories and electronic integrators.

  • 23.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Error sources in a laser anglemeter used for mobile robot navigation1993Rapport (Övrigt vetenskapligt)
  • 24.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lulea Turbo Turtle (LTT)1989Ingår i: The Autonomous Mobile Robots and Its Applications: Proceedings. IROS '89, 1989, s. 620-623Konferensbidrag (Refereegranskat)
  • 25.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    On a laser anglemeter for mobile robot navigation1993Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    A laser anglemeter for use in a navigation system for mobile robots has been developed. The anglemeter measures heading angles to beacons made of vertical stripes of retroreflective tape. The anglemeter uses an- optical system with a rotating mirror. It scans a laser beam which illuminates the beacons and receives pulses of reflected light from them. The pulses are amplified by a low-noise amplifier and then fed to a comparator. When the comparator trips it is assumed that the laser beam has hit a beacon. Then the angle is measured with a counter which is fed with pulses from an incremental encoder fixed on the axis of the mirror. A navigation system using the anglemeter has been developed. The system includes an algorithm that associates measured angles with beacon identities. The algorithm has been patented by the author. The navigation system has been implemented on a test vehicle. The optical and electronic parts of the anglemeter have been thoroughly analysed and simulated. The performance limits of the anglemeter are stated and design criteria for the optical and electronic parts are proposed. Measurements support the simulations and the theoretical analysis. Some results of the analysis of the optical part of the anglemeter are: A Gaussian expression describing the bidirectional reflection distribution function (BRDF) of the beacons is proposed. The shape and power of the received light pulses from the beacons are found to be determined by the (Gaussian) intensity distribution and the divergence of the laser beam, the scan velocity, the width of the beacons and their BRDFs. No signal is received from beacons at close range. At long range the laser beam diameter is much larger than the width of the beacons which causes the range-dependence of the width of the received pulses to disappear. The shape of the pulses is approximately Gaussian in this region due to the intensity distribution of the laser beam. The width of the pulses is determined by the laser beam divergence and the scan velocity. Optical misalignments in the anglemeter cause the dominating systematic error in measured angles. Another important error source is the range dependence of the received signal. Furthermore a non-circular cross-section of the laser beam is a potential source of large systematic errors while random errors due to electronic noise are surprisingly small. Some results of the analysis of the electronic part of the anglemeter axe: A low-noise photodiode-amplifier circuit with the photodiode in the feedback path has been developed. No noise generating resistor is needed to provide a DC-path to ground for signal and bias currents at the amplifier input. It is possible to design the amplifier as a matched filter for square shaped pulses. An implementation of the amplifier was found to have a NEP~ 3 fW/√Hz at frequencies below 10 kHz.

  • 26.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Optical navigation system using passive, identical beacons1987Ingår i: Intelligent autonomous systems: an international conference held in Amsterdam, The Netherlands, 8 - 11 December, 1986 / [ed] L. O. Hertzberger; F. C. A. Groen, Amsterdam: Elsevier, 1987, s. 737-741Konferensbidrag (Refereegranskat)
    Abstract [en]

    A prototype of an optical navigation system for autonomous vehicles has been built. It consists of an He-Ne laser, a rotating mirror, an incremental encoder, a receiving optical system, a low-noise detection system and some controlling and computing microcomputers. The prototype is mounted on-board an experimental autonomous vehicle. The vehicle is of the tricycle type with the drive and steer functions implemented in the front wheel. The number of beacons visible from the vehicle is normally much greater than three, which is the minimum needed to evaluate the position and direction of the vehicle uniquely. This redundancy makes the system robust against false detections and blocked beacons and also improves the accuracy. Another benefit from the great number of beacons is that the pattern of angles measured to the beacons gives the position and direction of the vehicle without the beacons identities' being known before-hand. The experimental set-up and some measurement results are presented

  • 27.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Optimum duty cycle for pulsed infrared emitting diodes1985Rapport (Övrigt vetenskapligt)
  • 28.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Range dependence of the shape and amplitude of the received pulse for a laser anglemeter used for mobile robot navigation1993Rapport (Övrigt vetenskapligt)
  • 29.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Signal response of a laser beam scanner1994Ingår i: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 33, nr 8, s. 2770-2776Artikel i tidskrift (Refereegranskat)
  • 30.
    Hyyppä, Kalevi
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ericson, Klas
    Luleå tekniska universitet.
    Low-noise photodiode-amplifier circuit1994Ingår i: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, E-ISSN 1558-173X, Vol. 29, nr 3, s. 362-365Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A photodiode-amplifier circuit with the photodiode in the feedback path is presented. It is named the PIF-circuit. No resistor is needed at the amplifier input to provide a path to ground for the signal and leakage currents from the photodiode and the amplifier input bias current. Therefore, one potentially dominating noise source is eliminated. At frequencies below 10 kHz, the implemented PIF-circuit has an NEP≈3 fW/√Hz

  • 31.
    Hyyppä, Kalevi
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Fredriksson, Håkan
    Innala Ahlmark, Daniel
    Nyberg, Lars
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Prellwitz, Maria
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Röding, Jenny
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Projekt: Seende rullstol2012Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Projektet syftar till att göra det möjligt för personer med funktionsnedsättning, som inte själva har full förmåga att styra en rullstol, att ändå nyttja den. Sensorer på rullstolen upptäcker automatiskt hinder i omgivningen och ger därmed den rörelsehindrade hjälp med styrningen.En virtuell blindkäpp som består av en haptisk robotarm kopplad till en laser som mäter avstånd till föremål i omgivningen har även tagits fram. Utifrån informationen skapas en 3D-bild som brukaren av den virtuella blindkäppen kan känna på med robotarmen.Fortsatt forskning kommer att fokusera på den virtuella vita käppen som kommer att ha en mycket längre räckvidd än en vanlig vit käpp. Vi avser att göra den handhållen så att rullstolen inte behövs som bärare av laserskanner och haptisk robot. En mycket viktig del i vår forskning är att åstadkomma en bra användarupplevelse. Synskadade, som har stor erfarenhet av den vanlig vita käppen, skall snabbt lära sig att använda den virtuella vita käppen.

  • 32.
    Hyyppä, Kalevi
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    PBL at Luleå University of Technology1995Ingår i: Proceedings: International conference on problem-based learning in higher education, September 24-27 1995 Linköping, Sweden, Linköping: Linköping universitet , 1995Konferensbidrag (Refereegranskat)
  • 33.
    Hyyppä, Kalevi
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Tanveer, Muhammad
    Projekt: Känsligare avståndssensor baserad på TOF, Fas II2012Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Vi planerar att utveckla ett enradschip i CMOS och därefter bygga en TOF-kamera baserad på detta chip.

  • 34.
    Hyyppä, Kalevi
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wernersson, Åke
    Andersson, Ulf
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Navigeringsexperiment med autonomt fordon1991Ingår i: Robotikdagar: robotteknik och verkstadsteknisk automation mot ökad autonomi ; 30 - 31 maj 1991, Linköping ; proceedings, Linköping, 1991Konferensbidrag (Refereegranskat)
  • 35.
    Hyyppä, Kalevi
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wiklund, Urban
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Optical navigation system using passive indentical beacons1987Rapport (Övrigt vetenskapligt)
  • 36.
    Hyyppä, Kalevi
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wiklund, Urban
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Andersson, Ulf
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wernersson, Åke
    Hillerström, Gunnar
    Zell, Caj
    Navigational experiments with the autonomous mobile robot ltt using angle measurements to identical beacons1994Ingår i: International Conference on Machine Automation: mechatronics spells profitability. Proceedings of the ICMA'94, Tampere University of Technology, 1994Konferensbidrag (Refereegranskat)
  • 37. Johansson, Gustav
    et al.
    Selinder, Johan
    Luleå tekniska universitet.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    DE-Link, an antenna pointing system for stratospheric balloons2005Ingår i: ICECS 2005: 12th IEEE International Conference on Electronics, Circuits, and Systems, 2005 : [Gammarth, Tunisia, December 11-14, 2005, Piscataway, N.J: IEEE Communications Society, 2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    The DE-Link attitude determination and pointing system onboard stratospheric balloons provides a low cost, low weight and high accuracy method to increase the efficiency of WLAN communication between balloon and ground station. By determination of the 6-dimensional pose of the balloon gondola in real-time, the WLAN antenna can be pointed toward a known position on the ground. This removes the need for power-consuming omnidirectional antennas. It also gives an improvement in communication speed and reduction of overall weight by the removal of heavy RF power amplifiers. The design uses a combination of GPS receivers, accelerometers and magnetoresistive circuits to determine the absolute attitude and position of the gondola in real-time, and two DC motors to point the antenna in azimuthand elevation directions to compensate for the movements of the gondola. Ground based tests have shown the system to function well with a pointing error of less than ±2 deg.

  • 38.
    Johnsson, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Alerby, Eva
    Luleå tekniska universitet, Institutionen för konst, kommunikation och lärande, Pedagogik språk och Ämnesdidaktik.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Jonsson, Håkan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Karlberg, Magnus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Stenberg, Magnus
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Arbetsvetenskap.
    Strömberg, Thomas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    En pedagogisk idé för ingenjörsutbildningarna vid Luleå tekniska universitet2009Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Utmärkande för Luleå tekniska universitet (LTU) har länge varit närheten mellan studenterna och lärarna vilket har manifesterats genom klassrumsundervisning, lärartillgänglighet, mindre studiegrupper, koncentrerade campus etc. Undervisningsformerna har dock ändrats till att idag omfatta dels klassiska föreläsningar i stora studentgrupper, men också projektarbete i team där totalt sett 1/3 av all undervisning vid Luleå tekniska universitet sker i projektform. En fråga har ställts: Har Luleå tekniska universitet idag en gemensam pedagogisk idé för ingenjörsutbildningarna? I så fall är ytterligare en fråga hur denna pedagogiska idé tar sig uttryck i organisationen?Intervjuer med 40 aktiva lärare vid Luleå tekniska universitet har genomförts av projektgruppen (tillika författarna) varpå svaren har grupperats och analyserats i fjorton olika teman. Från dessa teman har sedan fyra hörnstenar i en definition av en pedagogisk idé aggregerats. Formuleringen av den pedagogiska idén lyder: Ett aktivt lärande för yrkeslivet – i branschnära projekt och med god vetenskaplig grund tränas förmågan att arbeta som ingenjör genom coachning från lärare i ett nära och öppet klimat. Idén har antagits av den tekniska fakultetsnämnden vid Luleå tekniska universitet och verifierats på institutionerna. Exempel på implementering och hur den pedagogiska idén aktivt verkar presenteras i artikeln.

  • 39. Kozmin, Kirill
    et al.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Memory-efficient algorithm for lens distortion compensation2003Ingår i: Optics and Spectroscopy, ISSN 0030-400X, E-ISSN 1562-6911, Vol. 95, nr 1, s. 139-141Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Distortion introduced by a lens in a measurement system based on an image sensor usually must be compensated. The memory used for distortion compensation by a lookup table is proportional to the image sensor size. To reduce the memory usage, a compression algorithm is proposed and implemented.

  • 40.
    Larsson, Ulf
    et al.
    Luleå tekniska universitet.
    Jannok, D.
    Luleå tekniska universitet.
    Sandberg, U.
    Luleå tekniska universitet.
    Åhman, P.
    Luleå tekniska universitet.
    Franzén, M.
    Luleå tekniska universitet.
    Nilsson, R.
    Luleå tekniska universitet.
    Wernersson, Åke
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Calman : computerized articulated lawn mower with automatic navigation1993Ingår i: Proceedings: Robotikdagar 2-3 juni 1993 : automatiserad tillverkning - från högteknologi till tillämpning : Robotics Workshop, Linköping 1993, Linköping: Linköping University Electronic Press, 1993Konferensbidrag (Refereegranskat)
  • 41.
    Larsson, Ulf
    et al.
    Luleå tekniska universitet.
    Zell, Caj
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wernersson, Åke
    Navigating an articulated vehicle and reversing with a trailer1994Ingår i: Proceedings, 1994 IEEE International Conference on Robotics and Automation: May 8 - 13, 1994, San Diego, California, Los Alamitos, Calif: IEEE Computer Society Press , 1994, s. 2398-2404Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes two related tests; to navigate an articulated lawn mower and to reverse a mobile robot with a trailer. In both cases the vehicles are to follow a prespecified trajectory. The navigation principal is based on measured directions to several identical beacons, consisting of strips of reflective tapes. The angular sensor is a rotating laser for the illumination of the beacons and a highly sensitive electro-optical receiver for detecting the directions to the beacons. A Kalman filter is used to combine the measurements from the odometers with the detected angles to the known position of the beacons. To measure the angle between the robot and the trailer the same laser was used. This was done by placing two reflective beacons on the trailer. The repeatability was within 2 centimetre at low speed. The navigation of these two different types of vehicles turns out to be, essentially, the same problem. The sensitivities are different. Emphasis is on robust state estimation

  • 42.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nordlander, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Comprehensive reactive real-time programming2008Ingår i: Hawaii International Conference on Education: 2008 Conference Proceedings, 2008, s. 1440-1448Konferensbidrag (Refereegranskat)
  • 43.
    Nordin, Daniel
    et al.
    Luleå tekniska universitet.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Advantages of a new modulation scheme in an optical self mixing FMCW system2002Ingår i: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 41, nr 5, s. 1128-1133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new frequency-modulated continuous wave modulation scheme, which gives correct results even when the Doppler shift is larger than the frequency difference associated with the range, is presented and tested with a tunable laser diode and fiber-based system. By inserting a constant frequency region in the modulation scheme, both the magnitude and the sign of all beat frequencies can be determined. When they are known, the correct frequency difference as a result of the range can be calculated. This new scheme gives more freedom when choosing the modulation parameters of the laser, because increasing the modulation frequency, and/or the frequency sweep, to avoid ambiguities resulting from a large Doppler shift no longer becomes necessary. This is especially useful when using a somewhat cheaper laser diode source, since the maximum obtainable modulation frequency and frequency sweep can be somewhat limited. The suggested modulation scheme makes it possible to use some laser diodes in an application they otherwise would not be suited for.

  • 44.
    Nordin, Daniel
    et al.
    Luleå tekniska universitet.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Dividing optical power for maximum signal-to-noise ratio in a self mixing FMCW system2001Ingår i: Atmospheric Propagation, Adaptive Systems, and Laser Radar Technology for Remote Sensing, SPIE - International Society for Optical Engineering, 2001, s. 289-294Konferensbidrag (Refereegranskat)
    Abstract [en]

    An examination on how to divide the optical power between the local oscillator radiation and radiation sent towards the target for maximized signal-to-noise ratio, has been carried out. From the self-mixing equations, by substituting electrical fields with optical power and including relevant noise sources, an expression for the signal-to-noise ratio (SNR) for the photodiode has been obtained. From this equation the conditions for maximum SNR has been derived.

  • 45.
    Nordin, Daniel
    et al.
    Luleå tekniska universitet.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Finding the thermal time constants of a DFB laser module used in a FMCW ranging System2004Ingår i: Proceedings of ODIMAP IV, 4th Topical Meeting on Optoelectronic Distance/Displacement Measurements and Applications: University of Oulu, Finland, 16. - 18. June 2004, Oulu, 2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    In a frequency modulated continuous wave (FMCW) range and velocity-measuring system, knowledge of the thermal time constants of the laser module source is useful to obtain linear modulation. For each part of our DFB laser module a thermal resistance and capacitance were calculated, but measurements showed that our model was missing one significant time constant. FEMLAB simulations revealed that the missing time constant is of the same order of magnitude as the time it takes to heat up the area above the active region.

  • 46.
    Nordin, Daniel
    et al.
    Luleå tekniska universitet.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Single-stage photodiode op-amp solution suited for a self-mixing FMCW system2003Ingår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 52, nr 6, s. 1820-1824Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current delivered by the photodiode in a self-mixing frequency modulated continuous wave or optical frequency domain reflectometry system consists of a dc-current resulting from the local oscillator, the reflected signal, dark current in the photodiode, and current generated from background light. The current also contains the useful harmonic signal with a beat frequency corresponding to the range and radial velocity of a target. To avoid saturation and clipping due to the dc current generated in the photodiode, it is desirable to minimize the gain at dc while maintaining a high gain in the beat frequency region. We have investigated some different solutions and present a modified current-to-voltage converter using bootstrapping and added voltage gain, which addresses this problem using only one OP-amp and no dc shorting inductors.

  • 47.
    Nordin, Daniel
    et al.
    Luleå University of Technology.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Using a discrete thermal model to obtain a linear frequency ramping in a frequency-modulated continuous-wave system2005Ingår i: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 44, nr 7, s. 74202-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lasing wavelength of a single-section distributed feedback (DFB) laser diode can be modulated by modulating the drive current. This makes it possible to utilize the DFB laser diode in a frequency-modulated continuous wave (FMCW) range and velocity measuring system. In FMCW, the frequency of the laser is ramped, and the frequency difference between the reflected wave and a local-oscillator wave is monitored. For maximum performance the frequency ramping should be linear. Due to thermal phenomena, a linear ramping of the current seldom results in a linear ramping of the optical frequency. We have derived a discrete thermal model, using resistors and capacitors, of our laser module. The thermal model was then used as a starting point to model the frequency behavior of the laser and to derive modulation currents that resulted in a linear frequency ramping at some different modulation frequencies.

  • 48.
    Nybacka, Mikael
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Fredriksson, Håkan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Range data in vehicle dynamic simulation2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a way to merge range data into the vehicle dynamic simulation software CarSim 7.1. The range data consists of measurements describing the surface of a road, and thus, creates a close to real life 3D simulation environment. This reduces the discrepancy between the real life tests and simulation of vehicle suspension systems, dampers, springs, etc. It is important for the vehicle industry to represent a real life environment in the simulation software in order to increase the validity of the simulations and to study the effects that uneven roads have on the systems. Furthermore, a 3D environment based on real life data is also useful in driving simulators, when for example, analysing driver behaviour, testing driver response, and training for various driving conditions. To measure and collect data, a car was equipped with instruments and a computer. On top of the car, a SICK LMS200 2D lidar was mounted tilted downwards, facing the road in front of the car. To create the 3D environment, all the individual measurements were transformed to a global coordinate system using the pose (position and orientation) information from a high-class navigation system. 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 by CarSim software. This created the 3D road used in the vehicle dynamic simulations. The measurements were collected at a go-kart track in Lule°a, Sweden. Finally, tests have been performed to compare simulation results between using a 2D surface (i.e. flat) and a 3D surface (close to real life). It is seen that the simulation results using the 2D surface is clearly different from the 3D surface simulation.

  • 49. Nybacka, Mikael
    et al.
    Larsson, Tobias
    Jeppsson, Peter
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karlsson, Lennart
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Andren, Henrik
    Engström, Niclas
    Larsson, Roland
    Fransson, Lennart
    Hyyppä, Kalevi
    Fredriksson, Håkan
    Eriksson, Johan
    van Deventer, Jan
    Tingvall, Bror
    Project: CASTT - Centre for Automotive Systems Technologies and Testing2007Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Through the Centre for Automotive Systems Technologies and Testing, Luleå University of Technology aims to first of all support automotive winter testing in Northern Sweden. This means to support the local automotive test entrepreneurs and through them their customers: the car manufacturers and their suppliers. To succeed in this task, the center relies on the university's areas of leading research and most importantly on the cooperation between those areas.

  • 50.
    Röijezon, Ulrik
    et al.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Prellwitz, Maria
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Ahlmark, Daniel Innala
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A haptic navigation aid for individuals with visual impairments: Indoor and outdoor feasibility evaluations of the LaserNavigator2019Ingår i: Journal of Visual Impairment & Blindness, ISSN 0145-482X, E-ISSN 1559-1476, Vol. 113, nr 2, s. 194-201Artikel i tidskrift (Refereegranskat)
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