Terrain feature estimation method for a lower limb exoskeleton using kinematic analysis and center of pressure

Myounghoon Shim, Jong In Han, Ho Seon Choi, Seong Min Ha, Jung Hoon Kim, Yoon Su Baek

Research output: Contribution to journalArticle

Abstract

While controlling a lower limb exoskeleton providing walking assistance to wearers, the walking terrain is an important factor that should be considered for meeting performance and safety requirements. Therefore, we developed a method to estimate the slope and elevation using the contact points between the limb exoskeleton and ground. We used the center of pressure as a contact point on the ground and calculated the location of the contact points on the walking terrain based on kinematic analysis of the exoskeleton. Then, a set of contact points collected from each step during walking was modeled as the plane that represents the surface of the walking terrain through the least-square method. Finally, by comparing the normal vectors of the modeled planes for each step, features of the walking terrain were estimated. We analyzed the estimation accuracy of the proposed method through experiments on level ground, stairs, and a ramp. Classification using the estimated features showed recognition accuracy higher than 95% for all experimental motions. The proposed method approximately analyzed the movement of the exoskeleton on various terrains even though no prior information on the walking terrain was provided. The method can enable exoskeleton systems to actively assist walking in various environments.

Original languageEnglish
Article number4418
JournalSensors (Switzerland)
Volume19
Issue number20
DOIs
Publication statusPublished - 2019 Oct 2

Fingerprint

center of pressure
exoskeletons
walking
Point contacts
limbs
Biomechanical Phenomena
Walking
Lower Extremity
Kinematics
kinematics
Pressure
Stairs
Architectural Accessibility
least squares method
ramps
Least-Squares Analysis
safety
Extremities
Experiments
slopes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Atomic and Molecular Physics, and Optics
  • Instrumentation
  • Electrical and Electronic Engineering

Cite this

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abstract = "While controlling a lower limb exoskeleton providing walking assistance to wearers, the walking terrain is an important factor that should be considered for meeting performance and safety requirements. Therefore, we developed a method to estimate the slope and elevation using the contact points between the limb exoskeleton and ground. We used the center of pressure as a contact point on the ground and calculated the location of the contact points on the walking terrain based on kinematic analysis of the exoskeleton. Then, a set of contact points collected from each step during walking was modeled as the plane that represents the surface of the walking terrain through the least-square method. Finally, by comparing the normal vectors of the modeled planes for each step, features of the walking terrain were estimated. We analyzed the estimation accuracy of the proposed method through experiments on level ground, stairs, and a ramp. Classification using the estimated features showed recognition accuracy higher than 95{\%} for all experimental motions. The proposed method approximately analyzed the movement of the exoskeleton on various terrains even though no prior information on the walking terrain was provided. The method can enable exoskeleton systems to actively assist walking in various environments.",
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Terrain feature estimation method for a lower limb exoskeleton using kinematic analysis and center of pressure. / Shim, Myounghoon; Han, Jong In; Choi, Ho Seon; Ha, Seong Min; Kim, Jung Hoon; Baek, Yoon Su.

In: Sensors (Switzerland), Vol. 19, No. 20, 4418, 02.10.2019.

Research output: Contribution to journalArticle

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