Usability of Haptic Volumetric Assistance for Surgical Navigation Tasks

Abstract Manual control of surgical instruments represents a sensorimotor control task with at least 3-6 degrees of freedom (DoF). The impact of haptic guidance on volumetric navigation tasks, such as milling of planned volumes for prosthesis fits or preserving sensitive tissues, is investigated. Interaction centered studies are performed to evaluate the usability of the assistance modes for navigation within a volume, along the surface of a volume and around forbidden regions. Results show that haptic assistance can reduce the number of constraint violations, if the virtual stiffness is high enough. However, haptic assistance also can increase error rates when counterforces are close to the absolute perception threshold, as a false sense of security can arise. For navigation along complex surfaces bilateral haptic constraints should be preferred, while unilateral constraints are sufficient for simple geometries. This study complements previous publications as a basis for a flexible rule-based selection or adaptation of modular haptic assistance systems.

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The Impact of the Support System’s Kinematic Structure on Selected Kinematic and Dynamic Quantities of an Experimental Crane

Acta Mechanica et Automatica ◽

10.2478/ama-2014-0034 ◽

2014 ◽

Vol 8 (4) ◽

pp. 189-193 ◽

Cited By ~ 2

Author(s):

Arkadiusz Trąbka

Keyword(s):

Comparative Analysis ◽

Computational Model ◽

Experimental Model ◽

Support System ◽

Degrees Of Freedom ◽

Kinematic Structure ◽

Unilateral Constraints ◽

Adams Software ◽

The Impact

Abstract This paper presents a comparative analysis of two kinematic structures of the support system (with supports with bilateral and unilateral constraints), which were used in an experimental model of a crane. The computational model was developed by using the ADAMS software. The impact of the kinematic structure of the support system on selected kinematic and dynamic values that were recorded during the slewing motion was analysed. It was found, among other things, that an increased number of degrees of freedom of the support system leads to multiple distortions of time characteristics of kinematic and dynamic quantities.

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Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

10.26434/chemrxiv.12252059 ◽

2020 ◽

Author(s):

María Camarasa-Gómez ◽

Daniel Hernangómez-Pérez ◽

Michael S. Inkpen ◽

Giacomo Lovat ◽

E-Dean Fung ◽

...

Keyword(s):

Single Molecule ◽

Quantum Interference ◽

Degrees Of Freedom ◽

Building Blocks ◽

Ferrocene Derivative ◽

Single Molecule Junctions ◽

Molecule Junction ◽

Single Molecule Junction ◽

The Impact ◽

D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted some interest as functional elements of molecular-scale devices. Here we investigate the impact of the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction conductance. Measurements indicate that the conductance of the ferrocene derivative, which is suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.

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The halo model as a versatile tool to predict intrinsic alignments

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3802 ◽

2020 ◽

Author(s):

Maria Cristina Fortuna ◽

Henk Hoekstra ◽

Benjamin Joachimi ◽

Harry Johnston ◽

Nora Elisa Chisari ◽

...

Keyword(s):

Degrees Of Freedom ◽

Power Spectra ◽

Stage Iv ◽

Stage Iii ◽

Radial Dependence ◽

Additional Parameter ◽

Small Scales ◽

Cosmic Shear ◽

Galaxy Populations ◽

The Impact

Abstract Intrinsic alignments (IAs) of galaxies are an important contaminant for cosmic shear studies, but the modelling is complicated by the dependence of the signal on the source galaxy sample. In this paper, we use the halo model formalism to capture this diversity and examine its implications for Stage-III and Stage-IV cosmic shear surveys. We account for the different IA signatures at large and small scales, as well for the different contributions from central/satellite and red/blue galaxies, and we use realistic mocks to account for the characteristics of the galaxy populations as a function of redshift. We inform our model using the most recent observational findings: we include a luminosity dependence at both large and small scales and a radial dependence of the signal within the halo. We predict the impact of the total IA signal on the lensing angular power spectra, including the current uncertainties from the IA best-fits to illustrate the range of possible impact on the lensing signal: the lack of constraints for fainter galaxies is the main source of uncertainty for our predictions of the IA signal. We investigate how well effective models with limited degrees of freedom can account for the complexity of the IA signal. Although these lead to negligible biases for Stage-III surveys, we find that, for Stage-IV surveys, it is essential to at least include an additional parameter to capture the redshift dependence.

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A Superfluid Perspective on Neutron Star Dynamics

Universe ◽

10.3390/universe7010017 ◽

2021 ◽

Vol 7 (1) ◽

pp. 17

Author(s):

Nils Andersson

Keyword(s):

Neutron Star ◽

Degrees Of Freedom ◽

Temperature Scale ◽

Fluid System ◽

Fluid Core ◽

State Of Matter ◽

Entrainment Effect ◽

Neutron Component ◽

The Impact

As mature neutron stars are cold (on the relevant temperature scale), one has to carefully consider the state of matter in their interior. The outer kilometre or so is expected to freeze to form an elastic crust of increasingly neutron-rich nuclei, coexisting with a superfluid neutron component, while the star’s fluid core contains a mixed superfluid/superconductor. The dynamics of the star depend heavily on the parameters associated with the different phases. The presence of superfluidity brings new degrees of freedom—in essence we are dealing with a complex multi-fluid system—and additional features: bulk rotation is supported by a dense array of quantised vortices, which introduce dissipation via mutual friction, and the motion of the superfluid is affected by the so-called entrainment effect. This brief survey provides an introduction to—along with a commentary on our current understanding of—these dynamical aspects, paying particular attention to the role of entrainment, and outlines the impact of superfluidity on neutron-star seismology.

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A Traveler’s Guide to the Multiverse: Promises, Pitfalls, and a Framework for the Evaluation of Analytic Decisions

Advances in Methods and Practices in Psychological Science ◽

10.1177/2515245920954925 ◽

2021 ◽

Vol 4 (1) ◽

pp. 251524592095492

Author(s):

Marco Del Giudice ◽

Steven W. Gangestad

Keyword(s):

Degrees Of Freedom ◽

A Priori ◽

Simulated Data ◽

Style Analysis ◽

Data Set ◽

Scant Attention ◽

Equivalence Type ◽

The Impact ◽

Biased Estimates

Decisions made by researchers while analyzing data (e.g., how to measure variables, how to handle outliers) are sometimes arbitrary, without an objective justification for choosing one alternative over another. Multiverse-style methods (e.g., specification curve, vibration of effects) estimate an effect across an entire set of possible specifications to expose the impact of hidden degrees of freedom and/or obtain robust, less biased estimates of the effect of interest. However, if specifications are not truly arbitrary, multiverse-style analyses can produce misleading results, potentially hiding meaningful effects within a mass of poorly justified alternatives. So far, a key question has received scant attention: How does one decide whether alternatives are arbitrary? We offer a framework and conceptual tools for doing so. We discuss three kinds of a priori nonequivalence among alternatives—measurement nonequivalence, effect nonequivalence, and power/precision nonequivalence. The criteria we review lead to three decision scenarios: Type E decisions (principled equivalence), Type N decisions (principled nonequivalence), and Type U decisions (uncertainty). In uncertain scenarios, multiverse-style analysis should be conducted in a deliberately exploratory fashion. The framework is discussed with reference to published examples and illustrated with the help of a simulated data set. Our framework will help researchers reap the benefits of multiverse-style methods while avoiding their pitfalls.

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Kinematics of a Fully-Decoupled Remote Center-of-Motion Parallel Manipulator for Minimally Invasive Surgery

Journal of Medical Devices ◽

10.1115/1.4006541 ◽

2012 ◽

Vol 6 (2) ◽

Cited By ~ 45

Author(s):

Chin-Hsing Kuo ◽

Jian S. Dai

Keyword(s):

Minimally Invasive Surgery ◽

Minimally Invasive ◽

Invasive Surgery ◽

Inverse Kinematics ◽

Parallel Manipulator ◽

Degrees Of Freedom ◽

Surgical Instruments ◽

End Effector ◽

Minimally Invasive Surgical ◽

Inverse Kinematics Problem

A crucial design challenge in minimally invasive surgical (MIS) robots is the provision of a fully decoupled four degrees-of-freedom (4-DOF) remote center-of-motion (RCM) for surgical instruments. In this paper, we present a new parallel manipulator that can generate a 4-DOF RCM over its end-effector and these four DOFs are fully decoupled, i.e., each of them can be independently controlled by one corresponding actuated joint. First, we revisit the remote center-of-motion for MIS robots and introduce a projective displacement representation for coping with this special kinematics. Next, we present the proposed new parallel manipulator structure and study its geometry and motion decouplebility. Accordingly, we solve the inverse kinematics problem by taking the advantage of motion decouplebility. Then, via the screw system approach, we carry out the Jacobian analysis for the manipulator, by which the singular configurations are identified. Finally, we analyze the reachable and collision-free workspaces of the proposed manipulator and conclude the feasibility of this manipulator for the application in minimally invasive surgery.

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Investigation on the Robustness of Rotor/Stator Contact Interactions with Respect to Small Mistuning

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4051957 ◽

2021 ◽

Author(s):

Florence Nyssen ◽

Alain Batailly

Keyword(s):

Degrees Of Freedom ◽

Design Stage ◽

Contact Interactions ◽

Reduced Basis ◽

Amplification Factors ◽

Bladed Disk ◽

Nonlinear Amplification ◽

Rotor Stator Interaction ◽

Bending Modes ◽

The Impact

Abstract In this work, the impact of small mistuning on rotor/stator contact interactions is investigated. First, a detailed study of a rotor/stator interaction between the first bending modes and the second engine order is presented in the tuned case. Then, a numerical investigation on the effect of mistuning on the studied rotor/stator contact interaction is carried out. In particular, a stochastic analysis is performed to evaluate the robustness of the interaction with respect to the mistuning level. Simulations are conducted using a reduced order model (ROM) of an industrial bladed disk that combines both physical degrees of freedom (along blades tip for contact treatment) and modal coordinates. Mistuning is introduced in the tuned ROM by means of a modified version of the component mode mistuning method that allows to keep physical degrees of freedom within the reduced basis. Nonlinear amplification factors, i.e. the amplification factors in the context of contact nonlinearities, are compared with their linear counterparts, the latter are computed using a linear forcing on each blade using a two nodal diameters traveling wave excitation on the mistuned and the tuned bladed disk. The comparison between the linear and nonlinear amplification factor for each sample highlights that no correlation exists between a mistuning pattern leading to high amplifications in a linear context or when contact nonlinearities are taken into account. Therefore, dedicated analyses on the effect of mistuning should be undertaken with contact nonlinearities considerations at the design stage especially if intentional mistuning is considered.

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Surgical navigation with QR codes

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2016-0079 ◽

2016 ◽

Vol 2 (1) ◽

pp. 355-358

Author(s):

Manuel Katanacho ◽

Wladimir De la Cadena ◽

Sebastian Engel

Keyword(s):

Surgical Navigation ◽

Video Camera ◽

Surgical Instruments ◽

Qr Code ◽

Qr Codes ◽

Measurement Systems

AbstractThe presented work is an alternative to established measurement systems in surgical navigation. The system is based on camera based tracking of QR code markers. The application uses a single video camera, integrated in a surgical lamp, that captures the QR markers attached to surgical instruments and to the patient.

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Application of Simplified Parametric Model to Estimate Fan Blade-Out Response

Volume 7A: Structures and Dynamics ◽

10.1115/gt2018-77108 ◽

2018 ◽

Author(s):

Theodore S. Brockett ◽

Jerzy T. Sawicki

Keyword(s):

Degrees Of Freedom ◽

Initial Conditions ◽

Engine Performance ◽

Low Pressure ◽

External Loading ◽

System Response ◽

Angular Rotation ◽

Mass Eccentricity ◽

Fan Blade ◽

The Impact

A six-degree-of-freedom non-linear model is developed using Lagrange’s equation. The model is used to estimate transient fan-stage dynamic response during a fan-blade-out event in a turbo fan engine. The coupled degrees of freedom in the model include the fan whirl in the fan plane, the torsional response of the fan and low-pressure turbines (LPTs) about the engine centerline, the radial position of the released blade fragment, and the angular rotation of the trailing blade from its free state due to acceleration of the released blade. The released blade is assumed to slide radially outward along the trailing blade without friction. The external loading applied to the system includes fan imbalance, the remaining fan blades machining away the rub strip, rubbing of the blades with the fan case, and slowly-varying torques on the low pressure (LP) spool as engine performance degrades. The machining of the abradable imparts tangential loading on the fan blades as momentum is transferred to the liberated rub strip material. After application of the initial conditions including angular positions, angular velocities, released blade fragment position, and torsional wind-up, the governing equations are integrated forward in time from the instant the blade fragment is released. A reasonable match to test data is shown. Parameters affecting the fan-system response are varied to study the impact on fan peak lateral whirl amplitude, peak LP shaft torque, and peak loading on the trailing blade. It is found that the rub strip and mass eccentricity have the strongest influence on the LP shaft torsional loading. It is found that mass eccentricity has the largest influence on peak fan whirl. It is also found that released blade mass and attachment stiffness have the largest influence on the trailing blade loading.

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Enhancement of a 3-DOF submerged wave energy device using bistability

International Marine Energy Journal ◽

10.36688/imej.3.73-82 ◽

2020 ◽

Vol 3 (2) ◽

pp. 73-82

Author(s):

Benjamin Schubert ◽

William S. P. Robertson ◽

Benjamin S. Cazzolato

Keyword(s):

Wave Energy ◽

Degrees Of Freedom ◽

Phase Relationship ◽

Bistable System ◽

Viscous Drag ◽

Regular Waves ◽

Point Absorber ◽

Exciting Forces ◽

Bistable Mechanism ◽

The Impact

The dynamic response of a submerged CETO shaped quasi-point absorbing wave energy converter coupled to a bistable power take off is presented in this study. Whilst the impact of bistability has been shown in a limited number of situations to improve the amount of power generated, many models have been restricted to a single degree of freedom and often ignore drag effects. To overcome these model limitations, a submerged single tether point absorber with a bistable power take off was modelled using both 1 and 3 degrees of freedom. The device was subjected to regular waves and included a simple model of viscous drag. The bistable mechanism was provided by a magnetic dipole model quantified by a dimensionless parameter applicable to any bistable system. The performance of the device was is assessed by the theoretical power generated. Over each model, the previously observed benefit of bistability was not consistently obtained. Simulations of regular waves demonstrated an increase in generated power for suboptimal conditions for some frequencies, while a reduction in generated power was observed in optimal conditions. The performance increase showed strong correlation to the phase relationship between the motion and exciting forces as a result of bistability.

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