Development of three-dimensional position sensor for digestive tract measurement

Takashi Nagaoka, Sunao Takeda, Akihiko Uchiyama

Research output: Contribution to journalArticle


We developed three-dimensional position sensor that can measure the position of capsule in the digestive tract. For the purpose of inspecting new position measurement algorithm, we first developed prototype wired capsule-type sensor that is capable of being swallowed. Our ultimate goal will be to develop wireless sensor. The current sensor is applicable for medical capsule devices, such as capsule endoscope. The position of the sensor was detected using mutual induction. In order to maintain the electromotive force induced at secondary coils in the sensor constant, the current flowing into the primary coil was regulated using feedback control. The position of the sensor was measured stably using the feedback control, even when the sensor was relatively far from the primary coil. The position of the sensor was determined from the current flowing into the primary coil. As result of evaluating the accuracy of the wired sensor in vitro, the error was 2.90±2.10mm (Ave.±S.D.) in range of up to from the magnetic field generator. Moreover, using new position compensation algorithm, we were able to remove distortion caused by the magnetic field.

Original languageEnglish
Pages (from-to)239-249
Number of pages11
JournalJapanese Journal of Medical Electronics and Biological Engineering
Issue number4
Publication statusPublished - 2003


ASJC Scopus subject areas

  • Biomedical Engineering

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