NDLI: Instability Detection and Fall Avoidance for a Humanoid using Attitude Sensors and Reflexes

Content Provider	IEEE Xplore Digital Library
Author	Renner, R. Behnke, S.
Copyright Year	2006
Description	Author affiliation: Comput. Sci. Inst., Freiburg Univ. (Renner, R.; Behnke, S.)
Abstract	Humanoid robots are inherently unstable because their center of mass is high, compared to the support polygon's size. Bipedal walking currently works well only under controlled conditions with limited external disturbances. In less controlled dynamic environments, such as RoboCup soccer fields, external disturbances might be large. While some disturbances might be too large to prevent a fall, some disturbances can be dealt with by specific rescue behaviors. This paper proposes a method to detect instabilities that occur during omnidirectional walking. We model the readings of attitude sensors using sinusoids. The model takes the gait target vector into account. We estimate model parameters from a gait test sequence and detect deviations of the actual sensor readings from the model later on. These deviations are aggregated to an instability indicator that triggers one of two reflexes, based on indicator strength. For small instabilities the robot is slowing down, but continues walking. For stronger instabilities the robot stops and is brought into a stable posture with a low center of mass. Walking continues as soon as the instability disappears. We extensively evaluated our approach in simulation by disturbing the robot with a variety of impulses. The results indicate that our method is very effective. For smaller disturbances, the probability of a fall could be reduced to zero. Most of the medium-sized disturbances could also be rejected. For the evaluation with the real robot, we used a walking against a wall with different speeds and at various angles. Here the results show a similar outcome to the ones in the simulations
Starting Page	2967
Ending Page	2973
File Size	1164255
Page Count	7
File Format	PDF
ISBN	1424402581
DOI	10.1109/IROS.2006.282153
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2006-10-09
Publisher Place	China
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Legged locomotion Robot sensing systems Humanoid robots Parameter estimation Mobile robots Protection Stability Intelligent robots Intelligent sensors Sensor systems
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in