Lower-leg exoskeleton system and method
Inventors
Piercy, Brenton • Swift, Tim • Nucci, Giancarlo • Lamb, Callum • Lynn, Pete • Griffith, Saul • Luce, Leanne
Assignees
Publication Number
US-11213417-B2
Publication Date
2022-01-04
Expiration Date
2036-03-28
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Abstract
A lower-leg exoskeleton that includes an inflatable actuator configured to be worn over a front portion of a leg of a user and configured to be disposed directly adjacent to and surrounding a joint of the leg of the user. The inflatable actuator is configured, when worn by the user, to receive and transmit an actuator load generated by the inflatable actuator around the joint of the user to a load contact point. Inflation of the inflatable actuator generates a moment about the joint of the user to cause flexion of the leg of the user.
Core Innovation
The invention relates to a lower-leg exoskeleton that utilizes an inflatable actuator configured to be worn over the front portion of a user’s leg and disposed directly adjacent to and surrounding a leg joint, particularly the ankle. The inflatable actuator is designed to transmit actuator-generated loads around the user’s joint to a load contact point, typically located at the bottom of the user’s foot forward of the heel. Upon inflation, the actuator generates a moment about the joint, causing flexion of the leg or foot.
Conventional leg exoskeletons often feature interfaces between the exoskeleton and the user’s foot that are considered sloppy and transmit force through the heel, leading to unnatural gait patterns and limited movement capabilities such as squatting. The present invention addresses these issues by providing a new system and method for lower-leg exoskeletons, facilitating improved attachment and load transmission through the foot while minimizing discomfort.
Embodiments include features such as rigid or inflatable foot structures with sidewalls, base portions, and secure attachment points to ensure efficient force transmission without relying on the user's foot itself as the load path. The system allows for the actuator load to be directed through specific foot structures, such as the tarsals or metatarsals, and may integrate with specialized or conventional footwear. The actuator, which may have a C-shaped configuration with stacked bladder segments, interacts with rigid structures to provide desired movements, including plantar flexion, and can be operated by a pneumatic or fluidic control system.
Claims Coverage
There are several independent claims covering different aspects of the lower-leg exoskeleton system, focusing on the arrangement and interaction of inflatable actuators, rigid structures, and load transmission mechanisms.
Inflatable actuator and rigid foot structure for load transmission
The exoskeleton features an inflatable actuator adjacent to and surrounding the user's ankle, worn over the front portion of the foot. This actuator is coupled to a rigid foot structure with paired sidewalls and a removable base portion. The actuator and the rigid structure jointly transmit actuator-generated loads to a load contact point at the bottom of the foot, forward of the heel. Inflation of the actuator creates a moment about the ankle to cause flexion of the foot.
C-shaped inflatable actuator surrounding the ankle
A generally C-shaped inflatable actuator is placed directly adjacent to and surrounds the ankle, including the front and peripheral sides. The actuator and rigid structure transmit loads to a specified contact point at the bottom and front portion of the foot. The actuator's inflation is used to produce a flexing moment around the ankle.
Stacked bladder segment actuator configuration
The actuator may comprise a plurality of stacked bladder segments arranged in horizontal rows perpendicular to the axis of ankle rotation. This segmented configuration allows tailored expansion and controlled force generation when the actuator is inflated.
Fluidic system integration for actuation
The inflatable actuator is operably coupled with a fluidic (pneumatic) system that controls inflation and deflation. This integration enables controlled generation of moments for desired foot flexion movements.
Load path defined by rigid foot structure forward of the heel
The exoskeleton's rigid foot structure directs the actuator load to a contact point at the bottom of the foot, specifically forward of the heel. This arrangement bypasses the heel as the primary force transmission location, differing from conventional exoskeletons.
The independent claims collectively secure innovative combinations of inflatable actuators, rigid and adjustable foot structures, actuator-bladder configurations, fluidic controls, and forward load transmission mechanisms for improved lower-leg exoskeleton performance.
Stated Advantages
Provides more comfortable power transmission through the ankle compared to conventional exoskeletons.
Offers improved range of motion relative to traditional designs.
Minimizes user discomfort using semi-compliant and/or dynamically adjustable structures.
Allows efficient force output and control while maintaining a sufficiently rigid transmission path.
Enables easier and less obtrusive attachment and detachment with features like quick-connect and retractable attachment points.
Bypasses the user’s heel as the main force transmission point, reducing nonstandard gait and enabling more natural user movement.
Documented Applications
Assisting disabled users with mobility by regaining control or increasing strength in specific lower body parts.
Providing strength assistance or extra-human abilities in tasks such as lifting or carrying heavy objects.
Increasing stamina of the user through mechanical assistance.
Integrating the exoskeleton with both conventional and specialized footwear for different user needs.
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