| 1. |
- Bergblomma, Marcus, 1979-, et al.
(författare)
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A wireless low latency control system for harsh environments
- 2012
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Ingår i: IFAC Proceedings Volumes (IFAC-PapersOnline). - 9783902823144 ; , s. 17-22
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Konferensbidrag (refereegranskat)abstract
- The use of wireless communication technologies in the industry offer severaladvantages. One advantage is the ability to deploy sensors where they previously could noteasily be deployed, for instance on parts that rotate. To use wireless communication in industrialcontrol loops, demands on reliability and latency requirements has to be met. This in anenvironment that may be harsh for radio communication. This work presents a reliable, lowlatency wireless communication system. The system is used in a wireless thyristor control loopin a hydro power plant generator. The wireless communication is based on Bluetooth radiomodules. The work shows a latency analysis together with empirical hardware based latencyand packet error rate measurements. The background noise of a hydro power plant station isalso investigated. The average latency between the Bluetooth modules for the proposed systemis 5.09 ms. The packet error rate is 0.00288 for the wireless low latency control system deployedin a hydro power plant.
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| 2. |
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| 3. |
- Du, Jiaying, et al.
(författare)
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Noise reduction for a MEMS-gyroscope-based head mouse
- 2015
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Ingår i: Studies in Health Technology and Informatics, Volume 211. - Västerås, Sweden : IOS Press. - 9781614995159 ; , s. 98-104
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Konferensbidrag (refereegranskat)abstract
- In this paper, four different signal processing algorithms which can be applied to reduce the noise from a MEMS-gyroscope-based computer head mouse are presented. MEMS-gyroscopes are small, light, cheap and widely used in many electrical products. MultiPos, a MEMS-gyroscope-based computer head mouse system was designed for persons with movement disorders. Noise such as physiological tremor and electrical noise is a common problem for the MultiPos system. In this study four different signal processing algorithms were applied and evaluated by simulation in MATLAB and implementation in a dsPIC, with aim to minimize the noise in MultiPos. The algorithms were low-pass filter, Least Mean Square (LMS) algorithm, Kalman filter and Weighted Fourier Linear Combiner (WFLC) algorithm. Comparisons and system tests show that these signal processing algorithms can be used to improve the MultiPos system. The WFLC algorithm was found the best method for noise reduction in the application of a MEMS-gyroscope-based head mouse.
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| 4. |
- Du, Jiaying, et al.
(författare)
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Perception of Delay in Computer Input Devices Establishing a Baseline for Signal Processing of Motion Sensor Systems
- 2016
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Ingår i: The 3rd EAI International Conference on IoT Technologies for HealthCare HealthyIoT'16. - Västeraås, Sweden : Springer International Publishing. ; , s. 107-112
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Konferensbidrag (refereegranskat)abstract
- New computer input devices in healthcare applications using small embedded sensors need firmware filters to run smoothly and to provide a better user experience. Therefore, it has to be investigated how much delay can be tolerated for signal processing before the users perceive a delay when using a computer input device. This paper is aimed to find out a threshold of unperceived delay by performing user tests with 25 participants. A communication retarder was used to create delays from 0 to 100 ms between a receiving computer and three different USB-connected computer input devices. A wired mouse, a wifi mouse and a head-mounted mouse were used as input devices. The results of the user tests show that delays up to 50ms could be tolerated and are not perceived as delay, or depending on the used device still perceived as acceptable.
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| 5. |
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| 6. |
- Du, Jiaying, et al.
(författare)
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The effects of perceived USB-delay for sensor and embedded system development
- 2016
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBSVolume 2016. - 9781457702204 ; , s. 2492-2495
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Konferensbidrag (refereegranskat)abstract
- Perceiving delay in computer input devices is a problem which gets even more eminent when being used in healthcare applications and/or in small, embedded systems. Therefore, the amount of delay found as acceptable when using computer input devices was investigated in this paper. A device was developed to perform a benchmark test for the perception of delay. The delay can be set from 0 to 999 milliseconds (ms) between a receiving computer and an available USB-device. The USB-device can be a mouse, a keyboard or some other type of USB-connected input device. Feedback from performed user tests with 36 people form the basis for the determination of time limitations for the USB data processing in microprocessors and embedded systems without users' noticing the delay. For this paper, tests were performed with a personal computer and a common computer mouse, testing the perception of delays between 0 and 500 ms. The results of our user tests show that perceived delays up to 150 ms were acceptable and delays larger than 300 ms were not acceptable at all.
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| 7. |
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| 8. |
- Gerdtman, Christer, 1968-, et al.
(författare)
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A gyro sensor based computer mouse with a USB interface : A technical aid for motor-disabled people
- 2012
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Ingår i: Technology and disability. - : IOS Press. - 1055-4181. ; 24:2, s. 117-127
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to develop an alternative computer mouse for disabled persons. The mouse developed is a flexible input device with a multi-click function, which can be attached to a selectable body part (eg head, arm, foot). The mouse has a MEMS-gyroscope as the motion sensor, which is both small and sensitive. A USB-interface with a HID-profile is used to make the installation easy, "plug & play", and to make it compatible for use on any modern computer, independent of the operating system (Windows, Linux, Mac etc.). The structure is modular to achieve a flexible functionality. The mouse has individually adapted click-functions with selectable click devices, in addition to which, it is possible to define individual settings of the mouse parameters. The functionality can be extended by adding further personal settings, thereby programming the mouse for individual optimal performance. The result is a reliable and useful computer mouse for people with disabilities. In the development process, 23 users have been interviewed, three of whom participated in a 6 month long-term test. The study shows that a computer mouse incorporating a MEMS-gyroscope is a good, flexible solution, providing a high performance technical aid with extremely good sensitivity at a modest cost.
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| 9. |
- Gerdtman, Christer, et al.
(författare)
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A MEMS-gyro based computer mouse for disabled
- 2006
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Konferensbidrag (refereegranskat)abstract
- Computers are an important part of our daily lifes, and to be able to control them is in many cases necessary to be able to work, communicate or take part in our modern society of today. Therefore are persons that can not use an ordinary computer mouse in need of an alternative mouse. The reason of why an ordinary mouse can not be used is very different from person to person, depending on their abilities and needs. The need can also vary over time, not all persons are permanent handicapped, it can be a disability or bodily injury that can be healed. From these aspects, a computer mouse that can be used by a wide range of people with different types of disabilties and that can be applied on different body parts has been developed and evaulated.
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| 10. |
- Gerdtman, Christer, 1968-
(författare)
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Avancerade alternativa inmatningsenheter till datorer för funktionshindrade
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Datorn är ett viktigt verktyg i vår vardag. För rörelsehindrade kan datorn vara en förutsättning för att kunna fungera i vardagen. Datorn har som tekniskt hjälpmedel gett funktionshindrade större möjligheter till meningsfulla aktiviteter, såsom att på egen hand skriva, läsa och kommunicera. Samtidigt är det inte alltid funktionshindrade klarar av att använda vanliga datorer utan behöver alternativa inmatnings- och styrenheter. Målet med denna licentiatavhandling har varit att utveckla tekniker som ska stödja personer med rörelsebegränsningar. Främst har arbetet varit att utveckla alternativa tekniker för att kunna manövrera en dator. Viktiga aspekter i arbetet har varit att göra hjälpmedlen användarvänliga, möjliga att individanpassa, och att ta tillvara de tänkta användarnas synpunkter kring behov och önskemål. Vidare har inmatningsenheten utvärderats av användare och även tillämpats som ett rehabiliteringsverktyg för en mindre patientgrupp med nackskador, så kallade pisksnärtskador. Utöver dessa vetenskapliga mål har produktionsaspekterna varit viktiga. För att säkerställa att enheten ska kunna bli en produkt måste den kunna produceras och säljas till ett rimligt pris och detta måste beaktas under hela utvecklingsprocessen. En alternativ datormus baserad på MEMS-gyroskop har utvecklats. Utvecklingen är gjord utifrån de krav de tilltänka användarna ställde på den alternativa datormusen och enheten är utprovad och förbättrad i en iterativ process mellan utvecklare och användare, så kallad användarcentrerad utvecklingsprocess. MEMS-gyron var den typ av rörelsesensor som bäst svarade mot de krav som ställdes på enheten. De användare som deltog vid ett längre fältprov var samtliga nöjda och ville behålla musen. För att underlätta processen att välja rätt typ av gyro och att kunna utvärdera deras stabilitet under olika omgivningsfaktorer, såsom temperatur och vibrationer, har en testrig för gyron utvecklats. Människors rörelsemönster skiljer sig från industriella tillämpningar och därför behövs en speciell testrigg. Testriggen roterar gyron och mäter sensorsignalen under olika betingelser. Flera gyron kan testas samtidigt och testdatat kan sparas och analyseras i efterhand. Ett interaktivt datorbaserat träningsprogram har utvecklats och utvärderats vid en pilotstudie tillsammans med den alternativa datormusen. Syftet var att låta nackskadade utföra huvudrörelser och få en feedback på att de tränar rätt. Resultatet pekar på att detta kan vara en lovande metod.
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