A Chain-Driven, Sandwich-Legged Quadruped Robot: Design and Experimental Analysis

2025-03-18

AI Summary

Existing quadrupedal robot research platforms struggle to simultaneously achieve high locomotion performance, system reliability, and low-cost manufacturability. To address this, this work presents a medium-sized, open-source quadrupedal robot design. Methodologically, it introduces a novel stacked, lightweight “sandwich” leg architecture with a dual-motor serial drive layout—significantly reducing leg inertia—and integrates mechanical end-stops, cable strain relief, and active thermal management to enhance safety and robustness. Fabrication leverages a hybrid process of laser cutting and 3D printing, combined with quasi-direct-drive (QDD) actuators, enabling rapid prototyping (<25 kg total mass) at low cost (<$8,000). Experimental validation confirms stable trotting and crawling gaits on level ground and inclined surfaces, demonstrating high maneuverability and reproducibility. The platform is fully open-sourced, modular, and extensible, establishing a practical, accessible testbed for robotics research.

Technology Category

• Intelligent Robots: Motion and Path Planning
• Natural Language Processing: Safety and Robustness
• Planning, Routing, and Scheduling: Replanning and Plan Repair

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search

Abstract

This paper introduces a chain-driven, sandwich-legged, mid-size quadruped robot designed as an accessible research platform. The design prioritizes enhanced locomotion capabilities, improved reliability and safety of the actuation system, and simplified, cost-effective manufacturing processes. Locomotion performance is optimized through a sandwiched leg design and a dual-motor configuration, reducing leg inertia for agile movements. Reliability and safety are achieved by integrating robust cable strain reliefs, efficient heat sinks for motor thermal management, and mechanical limits to restrict leg motion. Simplified design considerations include a quasi-direct drive (QDD) actuator and the adoption of low-cost fabrication techniques, such as laser cutting and 3D printing, to minimize cost and ensure rapid prototyping. The robot weighs approximately 25 kg and is developed at a cost under $8000, making it a scalable and affordable solution for robotics research. Experimental validations demonstrate the platform's capability to execute trot and crawl gaits on flat terrain and slopes, highlighting its potential as a versatile and reliable quadruped research platform.

Problem

• Design a cost-effective, mid-size quadruped robot for research.
• Enhance locomotion and reliability with sandwich-legged design.
• Simplify manufacturing using low-cost techniques like 3D printing.

Innovation

• Chain-driven sandwich-legged quadruped robot design
• Dual-motor configuration for agile locomotion
• Low-cost fabrication with laser cutting and 3D printing