Next Article in Journal
An Adaptive Compensation Algorithm for Temperature Drift of Micro-Electro-Mechanical Systems Gyroscopes Using a Strong Tracking Kalman Filter
Next Article in Special Issue
Towards the Automatic Scanning of Indoors with Robots
Previous Article in Journal
Modification of an RBF ANN-Based Temperature Compensation Model of Interferometric Fiber Optical Gyroscopes
Previous Article in Special Issue
Quaternion-Based Unscented Kalman Filter for Accurate Indoor Heading Estimation Using Wearable Multi-Sensor System
Article Menu

Export Article

Open AccessArticle
Sensors 2015, 15(5), 11208-11221;

Afocal Optical Flow Sensor for Reducing Vertical Height Sensitivity in Indoor Robot Localization and Navigation

Department of Electrical and Computer Engineering, Automation and Systems Research Institute (ASRI), Seoul National University, Seoul 151-742, Korea
Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 151-742, Korea
Author to whom correspondence should be addressed.
Academic Editor: Kourosh Khoshelham
Received: 6 March 2015 / Revised: 16 April 2015 / Accepted: 8 May 2015 / Published: 13 May 2015
(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)
Full-Text   |   PDF [2787 KB, uploaded 13 May 2015]   |  


This paper introduces a novel afocal optical flow sensor (OFS) system for odometry estimation in indoor robotic navigation. The OFS used in computer optical mouse has been adopted for mobile robots because it is not affected by wheel slippage. Vertical height variance is thought to be a dominant factor in systematic error when estimating moving distances in mobile robots driving on uneven surfaces. We propose an approach to mitigate this error by using an afocal (infinite effective focal length) system. We conducted experiments in a linear guide on carpet and three other materials with varying sensor heights from 30 to 50 mm and a moving distance of 80 cm. The same experiments were repeated 10 times. For the proposed afocal OFS module, a 1 mm change in sensor height induces a 0.1% systematic error; for comparison, the error for a conventional fixed-focal-length OFS module is 14.7%. Finally, the proposed afocal OFS module was installed on a mobile robot and tested 10 times on a carpet for distances of 1 m. The average distance estimation error and standard deviation are 0.02% and 17.6%, respectively, whereas those for a conventional OFS module are 4.09% and 25.7%, respectively. View Full-Text
Keywords: optical flow sensor; indoor robot localization; navigation; dead reckoning optical flow sensor; indoor robot localization; navigation; dead reckoning

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Yi, D.-H.; Lee, T.-J.; Cho, D.-I. Afocal Optical Flow Sensor for Reducing Vertical Height Sensitivity in Indoor Robot Localization and Navigation. Sensors 2015, 15, 11208-11221.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Sensors EISSN 1424-8220 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top