Caterpillar Inc.

Harris Corporation

University of Florida Research Foundation Inc

Joseph F Duffy

Robert A Lapke

Carl David Crane

Randall A Harlow

James R Carlberg

Carl D Crane, Iii

Byron F Knight

Steven P Seaney

Steven C Swanson

Lionel A Martin

Michael W Griffis

Joseph Rooney

Joseph T Phillips

Rita R Waller

Methods and apparatuses for determining a mass of a payload in a work machine. The work machine has a chassis, a cab coupled with the chassis, and a boom coupled with the cab. A first actuator is coupled with the boom and the cab and moves the boom relative to the cab. The work machine has a stick coupled with the boom, and a second actuator coupled with the stick and the boom that moves the stick relative to the boom. The work machine also has a bucket operable to receive the payload. The bucket is coupled with the stick, and a third actuator is coupled with the bucket and the stick and moves the bucket relative to the stick. A first joint angle of the boom relative to the cab is determined at at least two instances in time. A second joint angle of the stick relative to the boom is determined at at least two instances in time. A third joint angle of the bucket relative to the stick is determined at at least two instances in time. A first actuator force exerted on the first actuator is determined at at least two instances in time. A second actuator force exerted on the second actuator is determined at at least two instances in time. A third actuator force exerted on the third actuator is determined at at least two instances in time. A plurality of physical characteristics of the work machine is determined. The mass of the bucket and payload is determined as a function of the first joint angles, the second joint angles, the third joint angles, the first actuator forces, the second actuator forces, the third actuator forces, and the plurality of predetermined physical characteristics.

Method and apparatus for determining a weight of a payload

A screw motion-driven tensegrity antenna support architecture is configured to stably deploy and adjustably control an energy-focusing surface, such as an RF wave-reflecting conductive mesh. A parallel platform structure is configured of an upper hexagonal platform and a lower hexagonal base, the perimeter geometry of each of which is defined by plural interconnected tensioned ties. Vertices of the hexagonal tie base and the hexagonal upper tie platform are interconnected by pairs of legs, each including a compression strut and a tension tie. The stability of the structure requires that the sum of the tie tension forces matches the sum of the compression forces in the struts. To control deployment from a stowed condition and the geometric parameters of the deployed RF reflecting surface, a screw motion-based drive system is coupled to the struts to define relative mutual rotation and pitch between the upper platform and lower base.

Deployable antenna using screw motion-based control of tensegrity support architecture

Access to an operator station of a large track-type tractor is provided by a ladder support structure pivotally attached to a portion of the radiator guard of the tractor. The ladder support structure extends over a track of the tractor and has a ladder pivotally attached to a distal end of the ladder support structure that provides steps over a push arm and a tilt cylinder of the tractor. When the ladder assembly is moved to its carry position, the ladder is moved to a position inside the ladder support structure, and the ladder support structure raised to a vertical position adjacent a side panel of the radiator guard of the tractor. The present invention avoids the problem of machine operators climbing on the push arms, tilt cylinders, radiator, radiator guard, track, hood, and engine enclosures in order to gain access to the operator station.

Ladder assembly for track-type tractors

A check valve normally blocks fluid flow from a bore to a passage and includes a spring normally holding a ball in sealing engagement with a valve seat to form a primary metal-to-metal hard seal. Another spring normally holds a poppet in engagement with another valve seat causing an annular protuberance formed on the poppet to sealingly engage a resilient seal to provide a more positive secondary soft seat seal. The poppet is unseated from the valve seat by a stem of a piston prior to the ball being unseated from the valve seat by a guide stem of the poppet so that the soft seal is opened at essentially zero flow conditions.

Soft seal poppet type check valve

A system, method and apparatus for controlling, via a closed-form forward displacement computation, the position and orientation of a movable platform of a parallel mechanism. A movable platform is supported above a base platform by a plurality of parallel support legs such as linear actuators. The dimensions of the base platform and the movable platform, as well the lengths of the support legs, are provided to a control system. The control system is operative to compute at least one closed-form forward displacement solution of the geometry of a polyhedron (an octahedron for the disclosed embodiments) formed by the movable platform, the base platform, and the support legs. The control system determines a final position and orientation of the movable platform by eliminating imaginary roots of the closed-form solutions and roots which would result in discontinuous paths of travel for the movable platform. A novel special 6-6 parallel mechanism is also disclosed. The control system is suitable for controlling known 3-3 or 6-3 Stewart platforms in a novel manner, as well as controlling the novel special 6-6 parallel mechanism. The special 6-6 parallel mechanism is distinguished from a general 6-6 by the fact that it is geometrically reducible to an octahedron, and therefore it has a simple geometry, even though its legs possess distinct connections. Also disclosed is a method for reducing the novel special 6-6 parallel mechanism to a Stewart platform equivalent, which is then controlled by the disclosed closed-form forward displacement control system.

Method and apparatus for controlling geometrically simple parallel

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Metamora, IL, United States of America

Joseph F Duffy