Swimming microrobot actuated by two pairs of Helmholtz coils system

Byun, Donghak; Choi, Jung Hye; Cha, Kyoungrae; Park, Jong-oh; Park, Sukho

doi:10.1016/j.mechatronics.2010.09.001

Cited by 55 publications

(28 citation statements)

References 5 publications

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“…However, with the assumption |x 1 | |x 2 |, we can obtain unique analytical solutions. In particular, we have arctan(x 2 /x 1 ) ≈ (x 2 /x 1 ) and (x 2 1 + x 2 2 ) ≈ x 2 1 . The equilibrium point can then be obtained as…”

Section: A Stability and Uniqueness Of Equilibriamentioning

confidence: 95%

“…It is easy to see that a 11 + a 22 = −(3c 1 + c 2 ) x 2 1 + x 2 2 , and thus is less than 0 except when x 1 = x 2 = 0. By canceling the terms m 2 m 1 x 3 and − m 1 m 2 x 3 in view of the negligible coupling terms in (8) and (9), we have a 11 a 22 − a 12 a 21 = 1/(m 1 m 2 ) (2c 2 1 + 2c 1 c 2 )(x 2 1 + x 2 2 ) + 2c 2 2 (x 2 1 + x 2 2 ) arctan 2 ( x 2 x 1 ) , which is always positive. From the above analysis, we show that the linearization matrix A is Hurwitz at an equilibrium point independent of its specific values, which proves the local asymptotic stability of the average model given a particular set of control input (α 0 , α A , ω α ).…”

Section: A Stability and Uniqueness Of Equilibriamentioning

confidence: 99%

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Averaging Tail-Actuated Robotic Fish Dynamics Through Force and Moment Scaling

Wang

Tan

2015

IEEE Trans. Robot.

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Averaging of robotic fish dynamics is of interest for the purposes of path planning and controller design due to the rhythmic movement of the robot. For a faithful dynamic model of robotic fish, however, classical averaging or geometric averaging typically cannot produce an average model that is accurate and in the meantime amenable to analysis or control design. In this paper, a novel averaging approach is proposed for tail-actuated robotic fish dynamics, in which the tail-generated hydrodynamic force is modeled with the Lighthill's large-amplitude elongated-body theory. The approach consists of scaling the force and moment terms and, then, conducting classical averaging. Numerical investigation reveals that the scaling function for the force term is a constant independent of tail-beat patterns, while the scaling function for the moment term depends linearly on the tail-beat bias. Extensive simulation and experimental results, comparing the predictions from the original and average models, are presented to support the effectiveness of the averaging approach. Existence and local stability of the equilibria for the average model are further analyzed. These equilibria are subsequently used to obtain an analytical solution for steady turning parameters, such as turning period and turning radius, without running simulation of the original or average dynamic models.

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Section: A Stability and Uniqueness Of Equilibriamentioning

confidence: 95%

Section: A Stability and Uniqueness Of Equilibriamentioning

confidence: 99%

Averaging Tail-Actuated Robotic Fish Dynamics Through Force and Moment Scaling

Wang

Tan

2015

IEEE Trans. Robot.

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“…126 Various groups have reported in vitro swimming of tail-flapping magnetic microrobots. 127,128,129 Design concepts for larger fish-like robots for underwater and marine exploration, employing streamlined and flexible bodies with single oscillating tails 130 could be miniaturized and explored for potential use in stomach endoscopy.…”

Section: B2 Fish-like Magnetic Capsulesmentioning

confidence: 99%

Magnetically guided capsule endoscopy

et al. 2017

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Wireless capsule endoscopy (WCE) is a powerful tool for medical screening and diagnosis, where a small capsule is swallowed and moved by means of natural peristalsis and gravity through the human gastrointestinal (GI) tract. The camera-integrated capsule allows for visualization of the small intestine, a region which was previously inaccessible to classical flexible endoscopy. As a diagnostic tool, it allows to localize the sources of bleedings in the middle part of the gastrointestinal tract and to identify diseases, such as inflammatory bowel disease (Crohn's disease), polyposis syndrome, and tumors. The screening and diagnostic efficacy of the WCE, especially in the stomach region, is hampered by a variety of technical challenges like the lack of active capsular position and orientation control. Therapeutic functionality is absent in most commercial capsules, due to constraints in capsular volume and energy storage. The possibility of using body-exogenous magnetic fields to guide, orient, power, and operate the capsule and its mechanisms has led to increasing research in Magnetically Guided Capsule Endoscopy (MGCE). This work shortly reviews the history and state-of-art in WCE technology. It highlights the magnetic technologies for advancing diagnostic and therapeutic functionalities of WCE. Not restricting itself to the GI tract, the review further investigates the technological developments in magnetically guided microrobots that can navigate through the various air-and fluid-filled lumina and cavities in the body for minimally invasive medicine.

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“…Because using the traditional endoscopic catheter is likely to cause injury to the soft tissue inside the human body, developing autonomous medical micro robots for use in human pipes has become a hot research topic in the fields of international medicine and electronics. Medical inpipe robots can be divided into passive capsule endoscopes, 1,2 active crawling in-pipe robots [3][4][5] and swimming in-pipe robots [6][7][8] and so on. When passive capsule endoscopes and active crawling in-pipe robots are operating in a pipe, they come into direct contact with the walls of the pipe.…”

Section: Introductionmentioning

confidence: 99%

Operational numerical simulation of a four-spiral in-pipe robot

Liang

Tang

et al. 2015

SIMULATION

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Based on an in-pipe robot with four spiral bodies in its tail, the dynamics equations of the fluid in the pipe are established when the robot runs. By using the computational fluid dynamics (CFD) method, the robot's force, circumferential torque and pressure on the pipe are numerically analyzed when the spiral directions of four spiral bodies are alternately left-handed and right-handed or are all left-handed, and different spiral directions correspond to different rotational directions. When the robot is needed to change direction, the rotational directional combinations of the four spiral bodies are calculated and designed. The results show that when the spiral directions of four spiral bodies alternate and the rotational directions of spiral bodies with different spiral directions are different, the formed axial thrust forces are the same, and the formed radial forces are counterbalanced, so that the robot moves axially in a balanced state. When the spiral and rotational directions of four spiral bodies are the same, the uniform axial thrust forces and a certain circumferential torque are formed, so that the robot moves axially in a rotating state. Under the two conditions, the robots can achieve turning arbitrarily. The turning directions of the four-spiral robots only relate to the rotational directions of the robotic spiral bodies. By contrasting the numerical values and the experimental values of the thrust forces between the cylinder and the spiral ribbed plate in the reference, the correctness of the numerical calculation method used in this paper is verified. The above research shows that such multi-spiral in-pipe robots are suitable to achieve inspection, dredging and other functions.

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Swimming microrobot actuated by two pairs of Helmholtz coils system

Cited by 55 publications

References 5 publications

Averaging Tail-Actuated Robotic Fish Dynamics Through Force and Moment Scaling

Averaging Tail-Actuated Robotic Fish Dynamics Through Force and Moment Scaling

Magnetically guided capsule endoscopy

Operational numerical simulation of a four-spiral in-pipe robot

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