Vanderbilt University

Brian Lawson

Michael Goldfarb

Jason E Mitchell

Huseyin Atakan Varol

Don Truex

Atakan Huseyin Varol

Amanda Huff Shultz

Harrison Bartlett

Frank Charles Sup, Iv

Andres Martinez-Guerra

Amanda Shultz

An exemplary robotic system includes a plurality of controllable joints and a controller. An exemplary control method provides for controlling the controllable joints by the controller. The control method provides for determining a configuration space for the robotic system and determining a reference movement path within the configuration space. The control method then provides for assigning a plurality of streamlines in the configuration space to yield a flow field based on the reference movement path. The control method then provides for measuring actual velocity vectors of the robotic system in the configuration space. The control method then provides for determining an error velocity vector based on a difference between the actual velocity vector and the desired velocity vector given by the flow field corresponding to the current robot configuration. The control method then provides for applying a total control vector at the plurality of controllable joints, by the controller, based on the error velocity vector.

Control method for a robotic system

Systems and methods of operating a lower limb device having at least a powered joint are provided. A method includes configuring the device to a first state in a finite state model for a current activity mode including a stair ascent mode or a stair descent mode. The method also includes, based on real-time sensor information, transitioning the device between different states in the finite state model when pre-defined criteria for transitioning among the different states are met. In the method, the finite state model for stair ascent includes lifting and swing phases, where the lifting phase includes a powered knee extension and a powered ankle push-off. The finite state model for stair descent includes yielding and swing states, where the swing states include providing a powered plantarflexion of the powered ankle joint and the yielding states include providing a resistive and passive plantarflexion of the powered ankle joint.

Stair descent control for powered lower limb devices

Systems and methods for a running controller for a lower limb device including at least a powered knee joint are provided. The method includes collecting real-time sensor information for the lower limb device and configuring the lower limb device to a first state in a finite state model for an activity mode including the running mode. The method further includes, based on the sensor information, transitioning the lower limb device from a current state to a subsequent state in the finite state model for the detected mode when a pre-defined criteria for transitioning to the subsequent state is met, and repeating the transitioning until the activity mode changes. In the system and method, the finite state model includes at least one stance state and at least one swing state, where the at least one stance state includes at least one absorption state and at least one propulsion state.

System and method for providing biomechanically suitable running gait in powered lower limb devices

An asymmetric linear actuator is provided which integrates a hydraulic dissipater and an electric motor and power screw which generates small forces. The actuator is configured so that an electric motor drives a power screw which drives a rod through a cylinder to provide linear actuation. The cylinder is fluid-filled and incorporates a piston that separates the cylinder into a first and second fluid chamber which are filled with a first and second volume of working fluid. Movement of the piston and rod assembly results in fluid movement between the first and second volumes of working fluid and through the fluidic restriction. The fluidic restriction can be proportionally controllable via an electric motor which enables controllable power dissipation via control of the fluidic restriction motor and controllable power generation via control of the power screw motor.

Linear actuator for asymmetric power generation and dissipation

Stair ascent control for powered lower limb devices

A device includes a first member and a second member disposed in series along a longitudinal axis. The device also includes links coupling first joints of the first member to second joints of the second member. The first and second members and the links arranged to define a planar parallelogram linkage. The devices also include a resilient element disposed between the first member and the second member, the first member and the second member preloaded against the resilient element. The first member and the second member are preloaded to provide an arrangement of the first and the second joints in which a motion of the first joints with respect to the second joints is constrained to a direction substantially parallel to the longitudinal axis. The devices further include a sensor for generating a signal indicating a separation between the first member and the second member.

Parallelogram load cell

Stair ascent and descent control for powered lower limb devices

Systems and methods for operating autonomous lower limb devices, including at least one adjustable joint and configured for at least supporting a body are provided. A method includes collecting real-time sensor information associated with the autonomous lower limb device. The method also includes receiving, over a communications link, remote data for at least one other lower limb device configured for supporting the body. The method further includes generating control data for transitioning the autonomous lower limb device from a current state in a current finite state model for operating the autonomous lower limb device to a different state in the current finite state model, where the different state is selected based on the real-time sensor information and the remote data.

Coordinating operation of multiple lower limb devices

Described herein are systems and methods for a powered ankle/foot prosthesis and controller that utilizes piecewise emulated passive impedances to provide for walking at various cadences and on various slopes and for ground slope adaptive standing. A powered prosthesis using these systems and methods is capable of emulating any physical behavior provided by the healthy joint, and additionally describes a control system that utilizes the sensing and actuation system on the prosthesis to provide appropriate ankle joint impedances. Further, the control system incorporates a finite-state-based structure, and within each state, emulates the behavior of the healthy joint with strictly passive impedance functions.

Walking controller for powered ankle prostheses

Systems and methods are provided for controlling a lower limb device having at least one powered joint. The method includes detecting a stumble event based on one or more sensor signals associated with an overall motion lower limb device, classifying the stumble event based on sensor signals following the sensor signals associated with the stumble event, and selecting a stumble recovery strategy for the lower limb device based on the classification of the stumble event.

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Nashville, TN, United States of America

Brian Lawson