MiNI-Q: A Miniature, Wire-Free Quadruped with Unbounded, Independently Actuated Leg Joints

TL;DR

MiNI-Q is a miniature, wire-free quadruped robot with unbounded, independently actuated leg joints, enabling versatile locomotion and complex maneuvers at a small scale, with open-source design files.

Contribution

This work introduces a novel miniature quadruped robot with mechanically unbounded joints and wire-free architecture, enhancing mobility and reliability over previous designs.

Findings

Achieves speeds up to 0.46 m/s

Demonstrates diverse locomotion including stair climbing and backflipping

Allows folding to a minimum height of 2.5 cm

Abstract

Physical joint limits are common in legged robots and can restrict workspace, constrain gait design, and increase the risk of hardware damage. This paper introduces MiNI-Q^2, a miniature, wire-free quadruped robot with independently actuated, mechanically unbounded 2-DOF leg joints. We present the mechanical design, kinematic analysis, and experimental validation of the proposed robot. The leg mechanism enables both oscillatory gaits and rotary locomotion while allowing the robot to fold to a minimum height of 2.5 cm. Experimentally, MiNI-Q achieves speeds up to 0.46 m/s and demonstrates low-clearance crawling, stair climbing, inverted locomotion, jumping, and backflipping. The wire-free architecture extends our previous Q8bot design, improving assembly reliability at miniature scale. All mechanical and electrical design files are released open source to support reproducibility and further research.