Design, dynamics, and dissipation of a torsional-magnetic spring mechanism

Kanj, Ali; Thanalakshme, Rhinithaa P.; Li, Chengzhang; Kulikowski, John; Bahl, Gaurav; Tawfick, Sameh

doi:10.1016/j.ymssp.2022.109307

Cited by 8 publications

(5 citation statements)

References 22 publications

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“…The planar-type micro-biopsy tools have been suggested for integration with the capsule-type endoscope and conventional forceps system [50]. For more recent work based on another mechanism, see the studies investigating a magnetic torsion spring mechanism for a wireless biopsy capsule [51] and a magnetic capsule endoscope carrying, releasing, and retrieving untethered microgrippers [52], which are proposed to be equipped to the small capsule.…”

Section: Discussionmentioning

confidence: 99%

A Planar-Type Micro-Biopsy Tool for a Capsule-Type Endoscope Using a One-Step Nickel Electroplating Process

Moon

2023

Micromachines

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Millimeter-scale biopsy tools combined with an endoscope instrument have been widely used for minimal invasive surgery and medical diagnosis. Recently, a capsule-type endoscope was developed, which requires micromachining to fabricate micro-scale biopsy tools that have a sharp tip and other complex features, e.g., nanometer-scale end-tip sharpness and a complex scalpel design. However, conventional machining approaches are not cost-effective for mass production and cannot fabricate the micrometer-scale features needed for biopsy tools. Here, we demonstrate an electroplated nickel micro-biopsy tool which features a planar shape and is suitable to be equipped with a capsule-type endoscope. Planar-type micro-biopsy tools are designed, fabricated, and evaluated through in vitro tissue dissection experiments. Various micro-biopsy tools with a long shaft and sharp tip can be easily fabricated using a thick photoresist (SU8) mold via a simple one-step lithography and nickel electroplating process. The characteristics of various micro-biopsy tool design features, including a tip taper angle, different tool geometries, and a cutting scalpel, are evaluated for efficient tissue extraction from mice intestine. These fabricated biopsy tools have shown appropriate strength and sharpness with a sufficient amount of tissue extraction for clinical applications, e.g., cancer tissue biopsy. These micro-scale biopsy tools could be easily integrated with a capsule-type endoscope and conventional forceps.

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Section: Discussionmentioning

confidence: 99%

A Planar-Type Micro-Biopsy Tool for a Capsule-Type Endoscope Using a One-Step Nickel Electroplating Process

Moon

2023

Micromachines

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“…where J m is the mover's moment of inertia and k d,rot is a strictly positive damping constant for the rotation. This constant arises from the magnetic interaction between the stator and mover, giving rise to eddy current and hysteresis losses in the PMs [29]. In the s domain, (4) with x m = 0 results in…”

Section: Rotational Dynamicsmentioning

confidence: 99%

Reaction Force-Based Position Sensing for Magnetic Levitation Platform with Exceptionally Large Hovering Distance

Bonetti,

Beglinger,

Mirić

et al. 2024

Actuators

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This work introduces a novel sensing concept based on reaction forces for determining the position of the levitating magnet (mover) for magnetic levitation platforms (MLPs). Besides being effective in conventional magnetic bearings, the applied approach enables operation in systems where the mover is completely isolated from the actuating electromagnets (EMs) of the stator (e.g., located inside a sealed process chamber) while levitating at an extreme levitation height. To achieve active position control of the levitating mover by properly controlling the stator’s EM currents, it is necessary to employ a dynamic model of the complete MLP, including the reaction force sensor, and implement an observer that extracts the position from the force-dependent signals, given that the position is not directly tied to the measured forces. Furthermore, two possible controller implementations are discussed in detail: a basic PID controller and a more sophisticated state-space controller that can be chosen depending on the characteristics of the MLP and the accuracy of the employed sensing method. To show the effectiveness of the proposed position-sensing and control concept, a hardware demonstrator employing a 207 mm outer-diameter (characteristic dimension, CD) stator with permanent magnets, a set of electromagnets, and a commercial multi-axis force sensor is built, where a 0.36 kg mover is stably levitated at an extreme air gap of 104 mm.

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“…However, these systems do have multiple sources of damping, which include various mechanical losses as well as eddy current damping. Typically, the dominant damping mechanism is associated with the mechanical suspensions for the rotors [5], [6] and has been extensively discussed elsewhere [19]- [23]. Eddy current damping originating from the time-varying magnetic fields and the moving conducting ferromagnetic materials (N52 neodymium alloy) also appears in MMRAs, but is relatively unexplored.…”

Section: Eddy Current Losses Intrinsic To An Mmramentioning

confidence: 99%

“…According to (23) and ( 25), the time-varying eddy current loss would be of the form P e (t) = P o sin 2 (ω b t), where P o is a constant under the quasi-static approximation and can be found in simulation (or experiment). We can then obtain the eddy current loss coefficient in that direction by computing…”

Section: Eddy Current Losses Intrinsic To An Mmramentioning

confidence: 99%

Frequency Response and Eddy Current Power Loss in Magneto-Mechanical Transmitters

Jing

Tawfick

Bahl

2023

IEEE Trans. Antennas Propagat.

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Magneto-mechanical transmitters offer a compact and low-power solution for the generation of ultra-low frequency (ULF) magnetic signals for through-ground and throughseawater communications. Resonant arrays of smaller magnetomechanical transmitters are particularly interesting in this context as the physical scaling laws allow for the increase of operating frequency and reduce the power requirements for ULF signal generation. In this work, we introduce a generalized model for accurate prediction of frequency and mode shape in generalized magneto-mechanical resonator arrays (MMRAs) that accounts for near-field magnetic interactions as well as magnetically induced nonlinearity. Using experiments, we demonstrate that our predictive capability is significantly improved compared against simplified dipole approximations. We additionally model the eddy current losses internal to the array and find that they are in agreement with experimental observations.

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Design, dynamics, and dissipation of a torsional-magnetic spring mechanism

Cited by 8 publications

References 22 publications

A Planar-Type Micro-Biopsy Tool for a Capsule-Type Endoscope Using a One-Step Nickel Electroplating Process

A Planar-Type Micro-Biopsy Tool for a Capsule-Type Endoscope Using a One-Step Nickel Electroplating Process

Reaction Force-Based Position Sensing for Magnetic Levitation Platform with Exceptionally Large Hovering Distance

Frequency Response and Eddy Current Power Loss in Magneto-Mechanical Transmitters

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