Stability of a Compass Gait Walking Model with Series Elastic Ankle Actuation

Date

2015-07-31

Author

Kerimoglu, Deniz
Morgul, Omer
Saranlı, Uluç

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

161
views

0
downloads

Passive dynamic walkers exhibit stable human-like walking on inclined planes. The simplest model of this behavior is the well known passive compass gait (PCG) model, which consists of a point mass at the hip and two stick legs. Due to their passive nature, these systems rely on a sloped ground to recover energy lost to ground collisions. A variety of methods have been proposed to eliminate this requirement by using different actuation methods. In this study, we propose a simple model to investigate how series elastic actuation at the ankle can be used to achieve stable walking on level ground. The structure we propose is designed to behave in a similar fashion to how humans utilize toe push-off prior to leg liftoff, and is intended to be used for controlling the ankle joint in a lower-body robotic orthosis. We present the derivation of the hybrid equations of motion for this model, resulting in a numerically computed return map for a single stride. We then numerically identify fixed points of this system and investigate their stability. We show that asymptotically stable walking on flat ground is possible with this model and identify the dependence of limit cycles and their stability on system parameters.

Subject Keywords

Legged locomotion, Limit-cycles, Springs, Mathematical model, Trajectory, Joints, Stability analysis

URI

https://hdl.handle.net/11511/46980

DOI

https://doi.org/10.1109/icar.2015.7251479

Collections

Department of Computer Engineering, Conference / Seminar

Suggestions

OpenMETU
Core

Stability and control of planar compass gait walking with series-elastic ankle actuation KERIMOGLU, Deniz; MORGUL, Omer; Saranlı, Uluç (2017-03-01) Passive dynamic walking models are capable of capturing basic properties of walking behaviours and can generate stable human-like walking without any actuation on inclined surfaces. The passive compass gait model is among the simplest of such models, consisting of a planar point mass and two stick legs. A number of different actuation methods have been proposed both for this model and its more complex extensions to eliminate the need for a sloped ground, balancing collision losses using gravitational potent...
Stability of Planar Compass Gait Walking with Series Elastic Ankle Actuation Kerimoğlu, Deniz; Morgül, Ömer; Saranlı, Uluç (null; 2015-07-24) Passive dynamic walking models capture the natural dynamics of stable human-like walking. The passive compass gait (PCG) model, consisting of a point mass and two rigid legs, is among the simplest of such models. The fully passive nature of these models, however, necessitates a sloped ground to recover the energy lost during the ground collisions [1]. A variety of methods have been proposed to eliminate this requirement through different actuation methods. Among these are impulsive energy injection after fo...
Flexible multibody dynamic modeling and simulation of rhex hexapod robot with half circular compliant legs Oral, Gökhan; Yazıcıoğlu, Yiğit; Department of Mechanical Engineering (2008) The focus of interest in this study is the RHex robot, which is a hexapod robot that is capable of locomotion over rugged, fractured terrain through statically and dynamically stable gaits while stability of locomotion is preserved. RHex is primarily a research platform that is based on over five years of previous research. The purpose of the study is to build a virtual prototype of RHex robot in order to simulate different behavior without manufacturing expensive prototypes. The virtual prototype is modele...
Identification of a vertical hopping robot model via harmonic transfer functions Uyanik, Ismail; Ankaralı, Mustafa Mert; Cowan, Noah J.; Saranlı, Uluç; Morgul, Omer (2016-05-01) A common approach to understanding and controlling robotic legged locomotion is the construction and analysis of simplified mathematical models that capture essential features of locomotor behaviours. However, the representational power of such simple mathematical models is inevitably limited due to the non-linear and complex nature of biological locomotor systems. Attempting to identify and explicitly incorporate key non-linearities into the model is challenging, increases complexity, and decreases the ana...
Analysis and Control of a Dissipative Spring-Mass Hopper with Torque Actuation Ankaralı, Mustafa Mert; Saranlı, Uluç (2011-01-01) It has long been established that simple spring-mass models can accurately represent the dynamics of legged locomotion. Existing work in this domain, however, almost exclusively focuses on the idealized Spring-Loaded Inverted Pendulum (SLIP) model and neglects passive dissipative effects unavoidable in any physical robot or animal. In this paper, we extend on a recently proposed analytic approximation to the stance trajectories of a dissipative SLIP model to analyze stability properties of a planar hopper w...

Citation Formats

D. Kerimoglu, O. Morgul, and U. Saranlı, “Stability of a Compass Gait Walking Model with Series Elastic Ankle Actuation,” 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46980.