ADMITTANCE SHAPING CONTROLLER FOR EXOSKELETON ASSISTANCE OF THE LOWER EXTREMITIES
First Claim
1. An exoskeleton system for assisted movement of legs of a user comprising:
- a harness worn around a waist of the user;
a pair of arm members coupled to the harness and to the legs;
a pair of motor devices, wherein one of the pair of motor devices is coupled to a corresponding arm member of the pair of arm members moving the pair of arm members for assisted movement of the legs; and
a controller coupled to the motor controlling movement of the assisted legs, the controller shaping an admittance of the system facilitating movement of the assisted legs by generating a target DC gain, a target natural frequency and a target resonant peak.
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Accused Products
Abstract
The control method for lower-limb assistive exoskeletons assists human movement by producing a desired dynamic response on the human leg. Wearing the exoskeleton replaces the leg'"'"'s natural admittance with the equivalent admittance of the coupled system formed by the leg and the exoskeleton. The control goal is to make the leg obey an admittance model defined by target values of natural frequency, resonant peak magnitude and zero-frequency response. The control achieves these objectives objective via positive feedback of the leg'"'"'s angular position and angular acceleration. The method achieves simultaneous performance and robust stability through a constrained optimization that maximizes the system'"'"'s gain margins while ensuring the desired location of its dominant poles.
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Citations
20 Claims
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1. An exoskeleton system for assisted movement of legs of a user comprising:
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a harness worn around a waist of the user; a pair of arm members coupled to the harness and to the legs; a pair of motor devices, wherein one of the pair of motor devices is coupled to a corresponding arm member of the pair of arm members moving the pair of arm members for assisted movement of the legs; and a controller coupled to the motor controlling movement of the assisted legs, the controller shaping an admittance of the system facilitating movement of the assisted legs by generating a target DC gain, a target natural frequency and a target resonant peak. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for controlling an exoskeleton system comprising:
a controller shaping an admittance of the system facilitating movement of assisted legs coupled to the system, wherein the controller models dynamics of one of the legs as a transfer function of a linear time-invariant (LTI) system, the controller replacing admittance of the one of the legs by an approximate equivalent admittance of a coupled leg and system by generating a target DC gain, a target natural frequency and a target resonant peak. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method for an exoskeleton assistive control comprising:
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calculating ratios between unassisted leg movement and a desired value through natural frequencies, resonant peaks and DC gains of the exoskeleton; calculating angular position feedback gain kDC of the exoskeleton system; calculating target admittance parameters ω
dnh and ζ
dh;obtaining a dominant pole of a target admittance as Phd=θ
hd+jω
dhd;obtaining parameters {σ
f, ω
d,f} of a feedback compensator of the exoskeleton system; andobtaining a loop gain KL and an inertia compensation gain Ic of the coupled exoskeleton system and legs of a user. - View Dependent Claims (20)
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Specification