This paper presents the mechanical design of a modular robot called the 3D M-Block, a 50mm cubic module capable of both independent and lattice-based locomotion. The first M-Blocks described in [1] could pivot about one axis of rotation only. In contrast, the 3D M-blocks can exert on demand both forward and backward torques about three orthogonal axes, for a total of six directions. The 3D M-Blocks transform these torques into pivoting motions which allow the new 3D M-Blocks to move more freely than their predecessors. Individual modules can employ pivoting motions to independently roll across a wide variety of surfaces as well as to join and move relative to other M-Blocks as part of a larger collective structure. The 3D M-Block maintains the same form factor and magnetic bonding system as the one-dimensional M-Blocks [1], but a new fabrication process supports more efficient and precise production. The 3D M-blocks provide a robust and capable modular self-reconfigurable robotic platform able to support swarm robot applications through individual module capabilities and self-reconfiguring robot applications using connected lattices of modules.

3D M-Blocks: Self-reconfiguring robots capable of locomotion via pivoting in three dimensions

Roombots: A hardware perspective on 3D self-reconfiguration and locomotion with a homogeneous modular robot

Employing Modular Robotic Systems (MRS) in different application domains confronts a large number of challenging problems in design, optimization, and planning, and so identifying characteristics of such problems is an important step toward finding proper solution approaches for them. In this paper, we address this issue and provide a comprehensive study on MRS through a structured survey about MRS characteristics and their applications. A novel framework called MITE is proposed to characterize both the properties and applications of MRS from four perspectives of Module, Information, Task, and Environment, based on more than 120 domain-specific features, supplemented by a mapping scheme for describing the interrelations of the four basic aspects of the Task component, namely, Application (for describing high-level tasks such as navigation and rescue), Behavior (for referring to constitutive behaviors like locomotion and manipulation which bring about Applications), Goal (for characterizing the way Behaviors are accomplished), and Operation (for designating activities specific to modular robots, such as self-reconfiguration and gait control). Also, by providing a methodical review on modular robotics, the paper deals with some analyses on recent trends, research gaps and challenges, as well as open problems in the field of MRS.

Modular Robotic Systems: Characteristics and Applications

Floor cleaning robot with reconfigurable mechanism

This article presents a review on trends in modular reconfigurable robots, comparing the evolution of the features of the most significant robots over the years and focusing on the latest designs. These features are reconfiguration, docking, degrees of freedom, locomotion, control, communications, size, and powering. For each feature, some of the most relevant designs are presented and the current trends in the design are discussed.

Current trends in reconfigurable modular robots design

In the paper, a concept of novel self-reconfigurable robotic system made of the autonomous robotic modules has been reviewed. Each robotic module is made of simple structure and few degrees of freedom; however, a group of the modules is able to change its connective configuration by changing their local connections and has functionality of robotic system which is capable of generating complicated motions and accomplishing a large variety of tasks, such as: transportation, exploration, inspection, construction and in-situ resource utilization. Multimode locomotion and self-reconfiguration are the basic and essential abilities for the self-reconfigurable robotic system. Based on this concept, a new self-reconfiguration system, UBot robotic system that combines the advantages from the chain-based and lattice-based robots has been proposed. Each UBot module which is cubic structure based on universal joint has two rotational DOF and four connecting surfaces that can connect to or disconnect from adjacent modules. The smart structure and the reliable connecting mechanism of the modules make the robot flexible enough to complete multimode locomotion and self-reconfiguration. This paper demonstrates the design philosophy of the UBot module and a solution for multimode motions and self-reconfiguration using the UBot system. The system can complete motion in the modes of quadruped, chain and loop configuration. Besides, the system can deform from one mode to the other though self-reconfiguration. All the proposed methods have been verified though simulations and real hardware experiments.

A new self-reconfigurable modular robotic system UBot: Multi-mode locomotion and self-reconfiguration

Purpose – The purpose of this paper is to introduce the design and the multi‐mode locomotion function of the new reconfigurable modular robotic system – UBot system – which combines the advantages from the chain‐based and lattice‐based self‐reconfigurable robots.Design/methodology/approach – The UBot modules the authors have designed are based on the universal joint and of cubic shape with two rotational joints and reliable automatic connecting mechanism. The modules are compact and flexible enough for locomotion and reconfiguration. The system can move in different modes to satisfy different terrains, through changing the modules' local connections and rotation of modules' joints.Findings – The UBot system can flexibly move in the modes of cross, loop, quadruped, snake‐type and other type of locomotion modes. All the locomotion has been implemented in the physical experiments.Originality/value – The UBot module is the new reconfigurable module which has two joints in one unit of regular cubic space and f...

UBot: a new reconfigurable modular robotic system with multimode locomotion ability

The design philosophy of UBot module is proposed in this paper. A novel modular self-reconfigurable robot called UBot is presented. The UBot module is compact, strength, flexible and capable of performing efficient locomotion, self-reconfiguration and manipulation tasks. This robot consists of several standard modules. Each module is cubic structure based on universal joint, and has four connecting surfaces that can connect to or disconnect from adjacent modules. A hook-type connecting mechanism is designed, which could connect to or disconnect from adjacent modules quickly and reliably. This mechanism is self-locking after connected, and energy-saving. Wireless communication technology was employed in the module, which can avoid cable-winding and improve flexibility of locomotion and self-reconfiguration. One simple orientation detecting system is designed, which can detect four possible orientations by metal contact points. A group of UBot modules can adapt their configuration and function to changing environment without external help by changing their connections and positions. To achieve small oversize and mass, compact mechanical structures and electrical systems are adopted in module designing. At last, the experiment of connecting mechanism and locomotion of UBot has been implemented.

The UBot modules for self-reconfigurable robot

The design and implementation of a novel modular Self-Reconfigurable Robot (SRR) called UBot is reviewed in this paper. Firstly, the philosophy of hardware design is presented. The module is designed with criteria such as cubic-shape, homogeneity, and strong connections to fulfill the requirements of complex three-dimensional reconfiguration and locomotion. Each robotic module has two degrees of freedom and four connecting surfaces with hook-type connecting mechanism. A group of modules can transform between different configurations by changing their local connections, achieve complicated modes of motion and accomplish a large variety of tasks. Secondly, a 3D dynamics simulator for UBot SRR is developed, where robot locomotion and transfiguration simulation could be done. A worm-like robot evolution is performed with results of a variety of high-performance locomotion patterns. Finally, Experiments are performed about autonomous docking, multi-mode locomotion and self-reconfiguration. The validity of docking method, CPG-network control and reconfiguration planning method is verified through locomotion and transformation tests of configurations such as snake-type, quadruped walking-type, omni-directional cross-type and loop-type.

Design and implementation of UBot: A modular Self-Reconfigurable Robot

Autonomous docking is still a major challenge for self-reconfigurable robots, it is an essential capability for the system to realize reconstruction, self-repairing and even for completing operational tasks in the complex environment. In this paper, we developed a new sensor module for the UBot self-reconfigurable robot system, and proposed a novel docking method for precise docking between module group with the sensor module and the target module. We describe this automated docking progress as three steps: The visual pre-positioning process; Precise positioning through hall sensors; Crawling and self-locking by the hook-type connecting systems. Finally, this method is proved to be effective by the S-4 module group automatic docking experiment.

Xindan Cui

Papers

A new self-reconfigurable modular robotic system UBot: Multi-mode locomotion and self-reconfiguration

UBot: a new reconfigurable modular robotic system with multimode locomotion ability

The UBot modules for self-reconfigurable robot

Design and implementation of UBot: A modular Self-Reconfigurable Robot

Multisensor-based autonomous docking for UBot modular reconfigurable robot