Limpet II: A Modular, Untethered Soft Robot

The ability to navigate complex unstructured environments and carry out inspection tasks requires robots to be capable of climbing inclined surfaces and to be equipped with a sensor payload. These features are desirable for robots that are used to inspect and monitor offshore energy platforms. Existing climbing robots mostly use rigid actuators, and robots that use soft actuators are not fully untethered yet. Another major problem with current climbing robots is that they are not built in a modular fashion, which makes it harder to adapt the system to new tasks, to repair the system, and to replace and reconfigure modules. This work presents a 450 g and a 250 × 250 × 140 mm modular, untethered hybrid hard/soft robot—Limpet II. The Limpet II uses a hybrid electromagnetic module as its core module to allow adhesion and locomotion capabilities. The adhesion capability is based on negative pressure adhesion utilizing suction cups. The locomotion capability is based on slip-stick locomotion. The Limpet II also has a sensor payload with nine different sensing modalities, which can be used to inspect and monitor offshore structures and the conditions surrounding them. Since the Limpet II is designed as a modular system, the modules can be reconfigured to achieve multiple tasks. To demonstrate its potential for inspection of offshore platforms, we show that the Limpet II is capable of responding to different sensory inputs, repositioning itself within its environment, adhering to structures made of different materials, and climbing inclined surfaces

Ship Hull Repair Using A Swarm Of Autonomous Underwater Robots: A Self-Assembly Algorithm

When ships suffer hull damage at sea, quick and effective repairs are vital. In these scenarios where even minutes make a substantial difference, repair crews need every edge they can get. In this paper, we propose a self-assembly algorithm to be used by a homogeneous swarm of autonomous underwater robots to aggregate at the hull breach and use their bodies to form a patch of appropriate size to cover the hole. Our approach is inspired by existing modular robot technologies and techniques, which are used to justify the feasibility of the proposed system presented in this paper. We test the ability of the agents to form a patch for various breach sizes and location and investigate the effect of varying population density. The system is verified within the two-dimensional Netlogo simulation environment and shows how the system performance can be quantified in relation to the sizes of the breach and the swarm. The methodology and simulation results illustrate that the swarm robot approach presented in this paper forms an important contribution in the emergency ship hull repair scenario and compares much advantageously against the traditional shoring methods. We conclude by suggesting how the approach may be extended to a three-dim

A modular robot system design and control motion modes for locomotion and manipulation tasks

This paper describes a modular robot system design SMART, based on three types of modules for urban search tasks. The system attempts to give a quick solution to natural and man-made disaster emergencies. It allows for rapid and cost-effective design and fabrication. The approach is based on the use of an inventory of three types of modules i.e., power and control module, joint module, and specialized module. They are interchangeable in different ways to form different robot configurations for a variety of tasks. Forward and inverse kinematics from assembled robot configurations are analyzed. Description of control motion modes for human-modular robot system interaction is presente

An autonomous self-reconfigurable modular robotic system with optimised docking connectors

Includes bibliographical references.Self-Reconfigurable Modular Robots are robotic systems consisting of a number of self-contained modules that can autonomously interconnect in different positions and orientations thereby varying the shape and size of the overall modular robot. This ground breaking capability is what in theory, makes self-reconfigurable modular robots more suitable for use in the navigation of unknown or unstructured environments. Here, they are required to reconfigure into different forms so as to optimise their navigation capabilities, a feat that is rendered impossible in conventional specialised robots that lack reconfiguration capabilities. However, the frequent development and use of self-reconfigurable modular robots in everyday robotic navigation applications is significantly hampered by the increased difficulty and overall cost of production of constituent robotic modules. One major contributor to this is the difficulty of designing suitably robust and reliable docking mechanisms between individual robotic modules. Such mechanisms are required to be mechanically stable involving a robust coupling mechanism, and to facilitate reliable inter-module power sharing and communication. This dissertation therefore proposes that the design and development of a functional low cost self-reconfigurable modular robot is indeed achievable by optimising and simplifying the design of a robust and reliable autonomous docking mechanism. In this study, we design and develop such a modular robot, whose constituent robotic modules are fitted with specialised docking connectors that utilise an optimised docking mechanism. This modular robot, its robotic modules and their connectors are then thoroughly tested for accuracy in mobility, electrical and structural stability, inter-module communication and power transfer, self-assembly, self-reconfiguration and self-healing, among others. The outcome of these testing procedures proved that it is indeed possible to optimise the docking mechanisms of self-reconfigurable modular robots, thereby enabling the modular robot to more easily exhibit efficient self-reconfiguration, self-assembly and self-healing behaviours. This study however showed that the type, shape, functionality and structure of electrical contacts used within the docking connectors for inter-module signal transfer and communication play a major role in enabling efficient self-assembly, self-reconfiguration and self-healing behaviours. Smooth spring loaded metallic electrical contacts incorporated into the docking connector design are recommended. This study also highlights the importance of closed loop control in the locomotion of constituent robotic modules, especially prior to docking. The open loop controlled locomotion optimisations used in this project were not as accurate as was initially expected, making self-assembly rather inaccurate and inconsistent. It is hoped that the outcomes of this research will serve to improve the docking mechanisms of self-reconfigurable modular robots thereby improving their functionality and pave the way for future large scale use of these robots in real world applications