Light Sailboats: Laser driven autonomous microrobots

We introduce a system of light driven microscopic autonomous moving particles that move on a flat surface. The design is simple, yet effective: Micrometer sized objects with wedge shape are produced by photopolymerization, they are covered with a reflective surface. When the area of motion is illuminated perpendicularly from above, the light is deflected to the side by the wedge shaped objects, in the direction determined by the position and orientation of the particles. The momentum change during reflection provides the driving force for an effectively autonomous motion. The system is an efficient tool to study self propelled microscopic robots

Active joints for microrobot limbs

The authors propose an electrostatic actuator for active joints. The active joint consists of two plates, one of which is a bilayer and bent by the bimorph effect. The plates are clamped to each other at one edge. A voltage between the plates leads to a very large field at the clamp where the plates are in intimate contact, thereby producing a force large enough to pull the bent bimorph cantilever beam to the other plate. The design uses an actuator in which large electrical forces acting over a short distance are used to produce large deflections. An appealing application of this actuation principle is seen in active joints for robot arms, e.g. by attaching members to the actuator and by combining two or more active joints and members to form micro robot arms, legs and grippers

Ferromagnetic microswimmers

Copyright © 2008 The American Physical SocietyWe propose a model for a novel artificial low Reynolds number swimmer, based on the magnetic interactions of a pair of ferromagnetic particles: one with hard and the other with soft magnetic properties, connected by a linear spring. Using a computational model, we analyze the behavior of the system and demonstrate that for realistic values of the parameters involved, the swimmer is capable of self-propelling with average speeds of the order of hundreds of micrometers per second

Magnetic microrobot and its application in a microfluidic system

AbstractThis paper researches the design and control method of a microrobot in a microfluidic system by electromagnetic field. The microrobot can move along the microchannel to a required position, and by changing the magnetic torque, the microrobot can also rotate in the microfluidic chip. As an application of the microrobot, it is used as a mobile micromixer to mix two solutions in the microfluidic chip, and the experimental results verify its effectiveness

Simulation of the active Brownian motion of a microswimmer

Cataloged from PDF version of article.Unlike passive Brownian particles, active Brownian particles, also known as microswimmers, propel themselves with directed motion and thus drive themselves out of equilibrium. Understanding their motion can provide insight into out-of-equilibrium phenomena associated with biological examples such as bacteria, as well as with artificial microswimmers. We discuss how to mathematically model their motion using a set of stochastic differential equations and how to numerically simulate it using the corresponding set of finite difference equations both in homogenous and complex environments. In particular, we show how active Brownian particles do not follow the Maxwell-Boltzmann distribution-a clear signature of their out-of-equilibrium nature- and how, unlike passive Brownian particles, microswimmers can be funneled, trapped, and sorted. (C) 2014 American Association of Physics Teachers

Acoustically-actuated bubble-powered rotational micro-propellers

Bubble-powered acoustic microsystems span a plethora of applications that range from lab-on-chip diagnostic platforms to targeted interventions as microrobots. Numerous studies strategize this bubble-powered mechanism to generate autonomous self-propulsion of microrobots in response to high frequency sound waves. Herein, we present two micro-propeller designs which contain an axis-symmetric distribution of entrapped bubbles that vibrate to induce fast rotational motion. Our micro-propellers are synthesized using 3D Direct Laser Writing and chemically-functionalized to selectively trap air bubbles at their micro-cavities which function as propulsion units. These rotational acoustic micro-propellers offer a dual advantage of being used as mobile microfluidic mixers, and as autonomous microrobots for targeted manipulation. With regards to targeted manipulation, we demonstrate magneto-acoustic actuation of our first propeller design that can be steered to a desired location to perform rotational motion. Furthermore, our second propeller design comprises of a helical arrangement of bubble-filled cavities which makes it suitable for spatial micro-mixing. Our acoustic propellers can reach speeds of up to 400 RPM (rotations per minute) without requiring any direct contact with a vibrating substrate in contrast to the state-of-the-art rotary acoustic microsystems

Relocating Units in Robot Swarms with Uniform Control Signals is PSPACE-Complete

This paper investigates a restricted version of robot motion planning, in which particles on a board uniformly respond to global signals that cause them to move one unit distance in a particular direction on a 2D grid board with geometric obstacles. We show that the problem of deciding if a particular particle can be relocated to a specified location on the board is PSPACE-complete when only allowing 1x1 particles. This shows a separation between this problem, called the relocation problem, and the occupancy problem in which we ask whether a particular location can be occupied by any particle on the board, which is known to be in P with only 1x1 particles. We then consider both the occupancy and relocation problems for the case of extremely simple rectangular geometry, but slightly more complicated pieces consisting of 1x2 and 2x1 domino particles, and show that in both cases the problems are PSPACE-complete

Enzyme-Powered Porous Micromotors Built from a Hierarchical Micro- and Mesoporous UiO-Type Metal–Organic Framework

Here, we report the design, synthesis, and functional testing of enzyme-powered porous micromotors built from a metal–organic framework (MOF). We began by subjecting a presynthesized microporous UiO-type MOF to ozonolysis, to confer it with mesopores sufficiently large to adsorb and host the enzyme catalase (size: 6–10 nm). We then encapsulated catalase inside the mesopores, observing that they are hosted in those mesopores located at the subsurface of the MOF crystals. In the presence of H2O2 fuel, MOF motors (or MOFtors) exhibit jet-like propulsion enabled by enzymatic generation of oxygen bubbles. Moreover, thanks to their hierarchical pore system, the MOFtors retain sufficient free space for adsorption of additional targeted species, which we validated by testing a MOFtor for removal of rhodamine B during self-propulsion.This work was supported by BIST-IGNITE (MOFtors), the Spanish MINECO (project RTI2018-095622-B-I00), the Catalan AGAUR (project 2017 SGR 238), and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 866348: iNanoSwarms). It was also funded by the CERCA Program/Generalitat de Catalunya. ICN2 is supported by the Severo Ochoa program from the Spanish MINECO (Grant No. SEV-2017-0706). Y.Y. acknowledges the China Scholarship Council for scholarship support. X.A. thanks the Spanish MINECO for the Severo Ochoa program (SEV-2014-0425) for the PhD fellowship (PRE2018-083712)