RhoMorph: Rhombus-Shaped Modular Robots for Stable, Medium-Independent Reconfiguration Motion
Jie Gu, Yirui Sun, Zhihao Xia, Tin Lun Lam, Chunxu Tian, Dan Zhang
AI summary
Problem
Existing modular self-reconfigurable robots struggle with high control complexity, reliance on external media for module detachment, or limited kinematic versatility during reconfiguration.
Approach
The authors design a rhombus-shaped module with a single central actuator that folds and unfolds along its diagonal, enabling modules to continuously pivot and reconnect while maintaining structural integrity.
Key results
- A compact, single-DoF rhombus module design with integrated cable-driven actuation and normally-on electromagnets
- A novel morphpivoting motion primitive and algorithm for continuous, tree-based reconfiguration
- Experimental validation of stable reconfiguration with approximately 4.8 mm x-axis and 15 mm y-axis kinematic accuracy in chain configurations
- Demonstrated reliable docking alignment within acceptable tolerances across multiple consecutive trials
Why it matters
It advances modular robotics by providing a reliable, medium-free reconfiguration method that simplifies control and enhances adaptability for multi-environment robotic systems.
Abstract
In this paper, we present RhoMorph, 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 sur- rounding medium, allowing the system to reliably form various configurations in diverse environments. To leverage the unique kinematics of RhoMorph, 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.