Stair and Ramp Recognition for Powered Lower Limb Exoskeletons

Konstantin Struebig, Niklas Ganter, Leon Freiberg, Tim C. Lueth

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

6 Scopus citations

Abstract

Robotic lower limb exoskeletons allow paraplegics to stand up, walk, and overcome obstacles like stairs and ramps. The selection of the required movement pattern is generally done manually by the user, which reduces the ease of use and prohibits dynamic transitions. The proposed solution for this problem is a machine vision based obstacle recognition system, which allows the exoskeleton to adapt its movements to the environment. To achieve this, the system needs to categorize the obstacle, determine its distance, and measure physical characteristics like step height and ramp slope.The developed system uses an infrared stereo camera paired with an IMU to capture a 3D point cloud of the path of the exoskeleton. Using the RANSAC algorithm, planes are segmented from the point cloud and stairs and ramps are identified based on the geometric constellation of the extracted planes. These surfaces are then used to calculate the quantitative characteristics of the obstacle, that would be needed for adaptive trajectory planning of an exoskeleton. To minimize the probability of wrong classifications or measurements, a higher level evaluation was integrated, which rates the quality of the gathered data based on redundant analyses and suppresses wrong results.The system was implemented on low power hardware intended for mobile applications to match the use case of a mobile exoskeleton. In first experiments, the system showed good results in terms of its detection rate and measurement accuracy, but is currently held back by long process run times due to hardware limitations.

Original languageEnglish
Title of host publication2021 IEEE International Conference on Robotics and Biomimetics, ROBIO 2021
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages1270-1276
Number of pages7
ISBN (Electronic)9781665405355
DOIs
StatePublished - 2021
Event2021 IEEE International Conference on Robotics and Biomimetics, ROBIO 2021 - Sanya, China
Duration: 27 Dec 202131 Dec 2021

Publication series

Name2021 IEEE International Conference on Robotics and Biomimetics, ROBIO 2021

Conference

Conference2021 IEEE International Conference on Robotics and Biomimetics, ROBIO 2021
Country/TerritoryChina
CitySanya
Period27/12/2131/12/21

Keywords

  • image processing
  • machine vision
  • obstacle recognition
  • plane detection
  • RANSAC
  • robotic exoskeletons

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