Scott B. Nokleby

An Explicit Method for Determining the Force-Moment Capabilities of Redundantly Actuated Planar Parallel Manipulators

A new explicit methodology for the determination of the force-moment capabilities of nonredundantly and redundantly actuated planar parallel manipulators (PPMs) is presented. This methodology is based on properly adjusting the actuator outputs to their maximum capabilities. As a result, the wrench to be applied or sustained is maximized. For a nonredundantly actuated PPM, one actuator can be maximized, while for a redundantly actuated PPM, one actuator, beyond the one of the nonredundant case, may be maximized for every degree of redundancy added to the mechanism. This methodology is compared to a previous work that required an optimization algorithm. The new method yields more accurate and reliable results and is considerably more efficient. Four studies of force-moment capabilities are considered: maximum force with prescribed moment, maximum applicable force, maximum moment with a prescribed force, and maximum applicable moment. The methodology is used to generate the force-moment capabilities of an existing PPM throughout its workspace.

Reciprocity-based resolution of velocity degeneracies (singularities) for redundant manipulators

Abstract A methodology for determining the velocity-degenerate (singular) configurations of joint-redundant manipulators is presented. The developed methodology uses the properties of reciprocal screws to determine all degenerate configurations resulting in a single degree-of-freedom (DOF) motion loss. Six joint screws (

Wrench capabilities of planar parallel manipulators. part i: Wrench polytopes and performance indices

sub1,

Design of a small-scale autonomous amphibious vehicle

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Optimization-Based Synthesis of Grashof Geared Five-Bar Mechanisms

sub6) are chosen to form one six-joint sub-group Jacobian, J sub . Setting the determinant of J sub to zero ( | J sub |=0 ) allows all conditions (say n in total) that cause the six-joint sub-group to become velocity degenerate to be identified. Reciprocal screws, W recip 1 , W recip 2 ,…, W recip n , can be found for each of the n velocity-degeneracy conditions. The reciprocal screw, W recip i , is reciprocal to the six joints that comprise J sub when the ith J sub degeneracy condition is true, but will not necessarily be reciprocal to the redundant joints

Wrench capabilities of planar parallel manipulators. part ii: Redundancy and wrench workspace analysis

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Identifying multi-DOF-loss velocity degeneracies in kinematically-redundant manipulators

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A New Method to Calculate the Force and Moment Workspaces of Actuation Redundant Spatial Parallel Manipulators

rk−6 (where k is the total number of joints and k>6). Taking reciprocal products of W recip i and each redundant joint

SYNTHESIS OF GRASHOF FOUR-BAR MECHANISMS USING PARTICLE SWARM OPTIMIZATION

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The Kinetostatic Conditioning of Two-Limb Schönflies Motion Generators

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