PARALLEL ELASTIC MECHANISM FOR ROBOT-ENVIRONMENT FORCE INTERACTION

Number: 20170317571
Published: 2017-11-02
Filed: 2016-04-28
Assignee: DISNEY ENTERPRISES, INC.
Inventors: KIM; JOOHYUNG, YAMANE; KATSU, BATTS; ZACHARY
CPC: H02K41/0356
Verdict: High Hardware
Source: Google Patents · FreePatentsOnline

The keeper's note

A prismatic actuator with a direct-drive voice-coil motor and spring element that imparts a hopping motion to a robot leg, storing and releasing elastic energy for force interaction with the environment.

Abstract

A prismatic actuator for imparting a hopping motion to a supported load such as a leg of robot. The apparatus includes a direct drive motor, such as a voice coil, operable to provide translational motion. The apparatus includes a spring element and a prismaticguide assembly. The guide assembly is configured to support the direct drive motor to constrain the translational motion to be along a drive axis and support the spring element toconstrain compression and expansion of the spring element along a longitudinal axis parallel to the drive axis. The apparatus includes a controller that: (1) first controls the direct drive motor to compress the spring element during a first time period beginning when the apparatus initially contacts a surface; and (2) second controls the direct drive motorto expand the spring element when the apparatus has zero velocity while contacting the surface.

Background

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic or functional block drawing of a hopping mechanism or apparatus of the present description;

FIG. 2 illustrates an axonometric view of portions of an exemplary hopping mechanism utilizing a LEAP with a voice coil motor combined with compression springs in parallel;

FIG. 3 is cross-sectional view of a cylindrical voice coil motor or assembly;

FIG. 4 is a graph showing the force-stroke relation for a representative voice coil motor or assembly;

FIG. 5 is an electric circuit diagram of a voice coil;

FIG. 6 illustrates a mechanical model of a hopping mechanism of the present description;

FIG. 7 illustrates graph providing results of simulating hopping heightversus spring stiffness;

FIG. 8 is a graph showing the voice coil force and currentsensor voltage relation (e.g., a linear relation between voice coil force and current sensor voltage);

FIG. 9 illustrates an experimental setup for testing operations of a hopping mechanism (such as the hopper of FIG. 2);

FIG. 10 provides graphs showing, respectively, torso and foot height plotted against time and commanded and measured voice coil force plotted against time; and

FIG. 11 illustrates a graph plotting hopping height versus spring stiffness for single and double spring configurations of the hopping mechanism as well as results of a simulation with 10% critical damping.DETAILED DESCRIPTION

Briefly, the foll

Claims

1. An apparatus for producing relative motion between a supported load and its environment, comprising: a direct drive motor directly coupled to the supported load and the environment operable to provide translational motion between the support load and the environment; an elastic element directly coupled to the supported load and the environment; and a prismatic guide assembly first supporting the direct drive motor to constrain the translational motion and second supporting the elastic element to constrain compression and expansion of the elastic element to be parallel to the translational motion. 14. An actuator mechanism, comprising: a voice coil comprising a coil and a body with an iron core and a space about the iron core for receiving the coil; a body support supporting the body of the voice coil; a coil support supporting the coil of the voice coil; a shaft extending between the coil support and body support; a translational bearing in the body support for slidingly engaging an end of the shaft; and an elastic element coupled to the body and coil supports. 20. An apparatus for imparting a hopping motion to a supported load, comprising: a voice coil operable to provide translational motion; an elastic element; a prismatic guide assembly first supporting the voice coil to constrain the translational motion to be along a drive axis and second supporting the elastic element to constrain compression and expansion of the spring element along a longitudinal axis that is parallel to the drive axis of the voice coil; and a controller first controlling the voice coil to compress the elastic element during a first time period beginning when the apparatus is sensed toinitially contact a surface and second controlling the voice coil to expand the elastic element during a second time period beginning when the apparatus is sensed to have zero velocity while contacting the surface.