Rhombot: Rhombus-shaped Modular Robots for Stable, Medium-Independent Reconfiguration Motion

2026-01-27

AI Summary

This work proposes Rhombot, a novel rhombus-shaped modular robot designed to overcome the challenges of stable, continuous, and control-simple reconfiguration in multi-medium environments—a longstanding limitation of conventional modular self-reconfigurable robots. Rhombot employs a single actuator to drive a parallelogram linkage along its diagonal, enabling folding motions that, when combined with a new reconfiguration primitive termed “morphpivoting” and a continuous execution control strategy, facilitate medium-agnostic, stable morphological transitions, docking, and locomotion. Experimental results demonstrate that Rhombot achieves highly stable reconfiguration, precise positioning, and reliable docking performance using minimal control complexity, thereby significantly enhancing both environmental adaptability and reconfiguration efficiency in modular robotic systems.

Technology Category

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

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

In this paper, we present Rhombot, a novel deformable planar lattice modular self-reconfigurable robot (MSRR) with a rhombus shaped module. Each module consists of a parallelogram skeleton with a single centrally mounted actuator that enables folding and unfolding along its diagonal. The core design philosophy is to achieve essential MSRR functionalities such as morphing, docking, and locomotion with minimal control complexity. This enables a continuous and stable reconfiguration process that is independent of the surrounding medium, allowing the system to reliably form various configurations in diverse environments. To leverage the unique kinematics of Rhombot, we introduce morphpivoting, a novel motion primitive for reconfiguration that differs from advanced MSRR systems, and propose a strategy for its continuous execution. Finally, a series of physical experiments validate the module's stable reconfiguration ability, as well as its positional and docking accuracy.

Problem

• modular self-reconfigurable robot
• reconfiguration
• medium-independent
• morphing
• docking

Innovation

• modular self-reconfigurable robot
• rhombus-shaped module
• morphpivoting
• medium-independent reconfiguration
• minimal actuation