Title
First Steps Towards Translating HZD Control of Bipedal Robots to Decentralized Control of Exoskeletons.
Abstract
This paper presents preliminary results toward translating gait and control design for bipedal robots to decentralized control of an exoskeleton aimed at restoring mobility to patients with lower limb paralysis, without the need for crutches. A mathematical hybrid dynamical model of the human-exoskeleton system is developed and a library of dynamically feasible periodic walking gaits for different walking speeds is found through nonlinear constrained optimization using the full-order dynamical system. These walking gaits are stabilized using a centralized (i.e., full-state information) hybrid zero dynamics-based controller, which is then decentralized (i.e., control actions use partial state information) so as to be implementable on the exoskeleton subsystem. A control architecture is then developed so as to allow the user to actively control the exoskeleton speed through his/her upper body posture. Numerical simulations are carried out to compare the two controllers. It is found that the proposed decentralized controller not only preserves the periodic walking gaits but also inherits the robustness to perturbations present in the centralized controller. Moreover, the proposed velocity regulation scheme is able to reach a steady state and track desired walking speeds under both, centralized, and decentralized schemes.
Year
DOI
Venue
2017
10.1109/ACCESS.2017.2690407
IEEE ACCESS
Keywords
Field
DocType
Exoskeletons,control design,robot control
Robot control,Control theory,Decentralised system,Gait,Control theory,Computer science,Robustness (computer science),Exoskeleton,Robot,Preferred walking speed
Journal
Volume
ISSN
Citations 
5
2169-3536
3
PageRank 
References 
Authors
0.43
17
9
Name
Order
Citations
PageRank
Ayush Agrawal130.43
Omar Harib2131.35
Ayonga Hereid38012.25
Sylvain Finet470.91
Matthieu Masselin571.25
Praly, L.61835364.39
Aaron D. Ames71202136.68
Koushil Sreenath835833.41
Jessy W. Grizzle9252.82