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Workspace Optimization of a Flexure-Based 3RRR Parallel Robot with Joint Angle Constraints

Annamalai Karuppiah, Ryan Orszulik

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AI summary

Key figure (auto-extracted from paper)

Accounting for initial end-effector orientation during kinematic optimization significantly expands the workspace of flexure-based parallel robots under joint angle constraints.

Flexure-based robots Workspace optimization 3RRR parallel manipulator Moore boundary algorithm Joint angle constraints Kinematic design

Problem

Traditional workspace optimization for flexure-based parallel robots often ignores joint angle limits or couples kinematic and structural analysis, leading to high computational costs and suboptimal designs.

Approach

The authors decouple the design process by using a modified Moore boundary-following algorithm to rapidly compute workspace boundaries under joint constraints, then optimize the leg ratio and initial end-effector orientation separately.

Key results

Modified Moore boundary algorithm computes workspace boundaries 50× faster than exhaustive grid search while capturing non-convex shapes.
Initial end-effector orientation critically affects workspace volume under joint constraints, yielding over 2500 mm²·deg gains in tested configurations.
Optimal leg ratio and initial orientation values are identified for maximizing workspace across various active and passive joint angle limits.
A decoupled kinematic-structural optimization framework reduces computational complexity for flexure-based robot design.

Why it matters

Enables mesoscale robotics engineers to rapidly design compliant parallel manipulators with maximized range of motion and precision for micro-manipulation applications.

Abstract

The optimization of flexure-based planar parallel robots with traditional methods demands significant computa- tional resources due to the coupling of kinematic and structural effects. This work presents a decoupled optimization approach, in which the geometry of the manipulator is optimized for workspace via a kinematic model approach. A novel approach is presented via a modified Moore boundary following algorithm which provides for an efficient calculation of the workspace. With this approach, the optimal kinematic design parameters, namely the leg ratio and initial orientation of the end effector are determined and presented for a number of cases described by the combination of joint angle constraints.

Index terms

Parallel Robots Compliant Joints and Mechanisms Kinematics