8,947 research outputs found
Design and optimal springs stiffness estimation of a Modular OmniCrawler in-pipe climbing Robot
This paper discusses the design of a novel compliant in-pipe climbing modular
robot for small diameter pipes. The robot consists of a kinematic chain of 3
OmniCrawler modules with a link connected in between 2 adjacent modules via
compliant joints. While the tank-like crawler mechanism provides good traction
on low friction surfaces, its circular cross-section makes it holonomic. The
holonomic motion assists it to re-align in a direction to avoid obstacles
during motion as well as overcome turns with a minimal energy posture.
Additionally, the modularity enables it to negotiate T-junction without motion
singularity. The compliance is realized using 4 torsion springs incorporated in
joints joining 3 modules with 2 links. For a desirable pipe diameter (\text{\O}
75mm), the springs' stiffness values are obtained by formulating a constraint
optimization problem which has been simulated in ADAMS MSC and further
validated on a real robot prototype. In order to negotiate smooth vertical
bends and friction coefficient variations in pipes, the design was later
modified by replacing springs with series elastic actuators (SEA) at 2 of the 4
joints.Comment: arXiv admin note: text overlap with arXiv:1704.0681
Distributed Control of Microscopic Robots in Biomedical Applications
Current developments in molecular electronics, motors and chemical sensors
could enable constructing large numbers of devices able to sense, compute and
act in micron-scale environments. Such microscopic machines, of sizes
comparable to bacteria, could simultaneously monitor entire populations of
cells individually in vivo. This paper reviews plausible capabilities for
microscopic robots and the physical constraints due to operation in fluids at
low Reynolds number, diffusion-limited sensing and thermal noise from Brownian
motion. Simple distributed controls are then presented in the context of
prototypical biomedical tasks, which require control decisions on millisecond
time scales. The resulting behaviors illustrate trade-offs among speed,
accuracy and resource use. A specific example is monitoring for patterns of
chemicals in a flowing fluid released at chemically distinctive sites.
Information collected from a large number of such devices allows estimating
properties of cell-sized chemical sources in a macroscopic volume. The
microscopic devices moving with the fluid flow in small blood vessels can
detect chemicals released by tissues in response to localized injury or
infection. We find the devices can readily discriminate a single cell-sized
chemical source from the background chemical concentration, providing
high-resolution sensing in both time and space. By contrast, such a source
would be difficult to distinguish from background when diluted throughout the
blood volume as obtained with a blood sample
Multi-Objective Design Optimization of the Leg Mechanism for a Piping Inspection Robot
This paper addresses the dimensional synthesis of an adaptive mechanism of
contact points ie a leg mechanism of a piping inspection robot operating in an
irradiated area as a nuclear power plant. This studied mechanism is the leading
part of the robot sub-system responsible of the locomotion. Firstly, three
architectures are chosen from the literature and their properties are
described. Then, a method using a multi-objective optimization is proposed to
determine the best architecture and the optimal geometric parameters of a leg
taking into account environmental and design constraints. In this context, the
objective functions are the minimization of the mechanism size and the
maximization of the transmission force factor. Representations of the Pareto
front versus the objective functions and the design parameters are given.
Finally, the CAD model of several solutions located on the Pareto front are
presented and discussed.Comment: Proceedings of the ASME 2014 International Design Engineering
Technical Conferences \& Computers and Information in Engineering Conference,
Buffalo : United States (2014
Navigation of mini swimmers in channel networks with magnetic fields
Controlled navigation of swimming micro robots inside fluid filled channels is necessary for applications in living tissues and vessels. Hydrodynamic behavior inside channels and interaction with channel walls need to be understood well for successful design and control of these surgical-tools-to-be. In this study, two different mechanisms are used for forward and lateral motion: rotation of helices in the direction of the helical axis leads to forward motion in the viscous fluid, and rolling due to wall traction results with the lateral motion near the wall. Experiments are conducted using a magnetic helical swimmer having 1.5 mm in length and 0.5 mm in diameter placed inside two different glycerol-filled channels with rectangular cross sections. The strength, direction and rotational frequency of the externally applied rotating magnetic field are used as inputs to control the position and direction of the micro swimmer in Y- and T-shaped channels
Mechanical Design and Dynamic Analysis of Pipe Crawling Robot for 6” to 10” diameter Internal Gas Pipeline Inspection
With the world moving forward, robot has been considered as an attractive and innovative alternative to help human in their work. For oil and gas industry, pipelines have been an important asset that needs to be maintained always. For many centuries, it has been integrals part of our constructions. However, with the cost of maintenance continue to increase, a new approach needed to accomplishing them.
Many different types of pipelines robot have been proposed in the past. Unfortunately, many of the robot work under very restricted area or environments such as customized pipes sometimes have no vertical movement or can traverse through only a simple pipeline structure. This project is targeted to build and design a functional robot where the application can be tailored to internal pipelines inspection and maintenance. With overcome the existing problem from the past pipeline inspection robot, a new and improved design will help in constructing the robot. The scope of this project is focused on mechanical and structural design of the pipe crawling robot. The methodology of this project will be involving research and identification, conceptual and system design including analysis, construction of the prototype, simulation testing and analysis and completing the final report. In the end of this project will be able to develop a simulation model of pipe crawling robot for internal pipeline inspection. The related mechanical model and analyzing of the mechanical design and active adaption to pipe diameter, tractive force adjusting, control system structure are discussed. As a pipe crawling robot for visual inspection, this project can become the fundamental for other inspection robo
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