A Workspace based Classification of 3R Orthogonal Manipulators

TL;DR

This paper introduces a new classification system for 3R orthogonal manipulators based on workspace topology, specifically analyzing singular curves and their cusps and nodes, to better understand their configuration space.

Contribution

It provides a novel classification framework based on workspace topology, with explicit expressions for separating surfaces in the design parameter space.

Findings

Nine distinct workspace topologies identified

Explicit formulas for separating surfaces in DH-parameters

Partitioning of design space into subspaces based on topology

Abstract

A classification of a family of 3-revolute (3R) positioning manipulators is established. This classification is based on the topology of their workspace. The workspace is characterized in a half-cross section by the singular curves of the manipulator. The workspace topology is defined by the number of cusps and nodes that appear on these singular curves. The design parameters space is shown to be partitioned into nine subspaces of distinct workspace topologies. Each separating surface is given as an explicit expression in the DH-parameters.