Assessment of suturing in the vertical plane shows the efficacy of the multi-degree-of-freedom needle driver for neonatal laparoscopy

This study presents dynamic modeling and simulation of an air vehicle consisting of a body, gripper and a claw. This model is inspired from birds’ aerial hunting, while considering the extra degree of freedom associated with the claw. For a manipulator like a gripper, additional degree of freedom creates more flexibility for grasping. The main contribution of this paper focuses on the development of a model that is suitable for trajectory optimization in grasping phase. Mathematical representation of the system is developed based on the Newton-Euler approach in MATLAB-Simulink environment, considering the motion in vertical plane. The dynamic behavior of the system is evaluated by simulation in variety situations and sensitivity analysis is carried out to determine and characterize the parameters having the most and least effects on grasping. It is shown that the initial position of the gripper and the claw as well as the additional mass that is added to the system in grasping phase make considerable changes in the dynamics that necessitates the use of the control system. In addition, smooth trajectories and controls are obtained by adding friction to the system in order to avoid dynamic divergence.

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Stability and nonlinear controllability analysis of a quadrotor-like autonomous underwater vehicle considering variety of cases

International Journal of Advanced Robotic Systems ◽

10.1177/1729881418819401 ◽

2018 ◽

Vol 15 (6) ◽

pp. 172988141881940 ◽

Cited By ~ 2

Author(s):

Liwei Kou ◽

Ji Xiang ◽

Yanjun Li ◽

Jingwei Bian

Keyword(s):

Horizontal Plane ◽

Autonomous Underwater Vehicle ◽

Vertical Plane ◽

Underwater Vehicle ◽

Plane Motion ◽

Small Time ◽

Degree Of Freedom ◽

Local Controllability ◽

Actuation System ◽

Nonlinear Controllability

A quadrotor-like autonomous underwater vehicle that is similar to, yet different from quadrotor unmanned aerial vehicles, has been reported recently. This article investigates the stability and nonlinear controllability properties of the vehicle. First, the 12-degree-of-freedom model of the vehicle deploying an X shape actuation system is developed. Then, a stability property is investigated showing that the vehicle cannot be stabilized by a time invariant smooth state feedback law. After that, by adopting a nonlinear controllability analysis tool in geometric control theory, the small-time local controllability of the vehicle is analyzed for a variety of cases, including the vertical plane motion, the horizontal plane motion, and the three-dimensional space motion. Finally, different small-time local controllability conditions for different cases are developed. The result shows that the small-time local controllability holds for vertical plane motion and horizontal plane motion. However, the full degree of freedom kinodynamics model (i.e. 12 states) of the vehicle does not satisfy the small-time local controllability from zero-velocity states.

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Modeling of Wing Flapping Motion

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.842.132 ◽

2016 ◽

Vol 842 ◽

pp. 132-140

Author(s):

Tien Dat Nguyen ◽

Subhan Sdywaliva ◽

Taufiq Mulyanto

Keyword(s):

Unmanned Aerial Vehicle ◽

Horizontal Plane ◽

Vertical Plane ◽

Degree Of Freedom ◽

Pitching Motion ◽

Flapping Motion ◽

Aerial Vehicle ◽

Animal World

In flying animal world, there are different flapping motions to produce lift and thrust depending on their species and size. Recent development in Unmanned Aerial Vehicle had tried to mimic flying animal. Rather than having two separate systems in providing lift and thrust, the wing upstroke and downstroke movement combined with wing twisting produce the necessary lift and thrust. Insects and some small birds have even the ability to fly hover.The present study is focused on the modeling of wing flapping motion. Instead of only accommodating flapping motion in a vertical plane and spanwise pitching motion, the model permits to include wing lead-lag motion in the horizontal plane. This more degree of freedom permit to model more complex wing flapping motion.

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Kinematic Design of a New Four Degree-of-Freedom Parallel Robot for Knee Rehabilitation

Journal of Mechanical Design ◽

10.1115/1.4040168 ◽

2018 ◽

Vol 140 (9) ◽

Cited By ~ 1

Author(s):

Jokin Aginaga ◽

Xabier Iriarte ◽

Aitor Plaza ◽

Vicente Mata

Keyword(s):

Vertical Plane ◽

Parallel Robot ◽

Singularity Analysis ◽

Parallel Robots ◽

Degree Of Freedom ◽

Mobile Platform ◽

Rehabilitation Robots ◽

Knee Rehabilitation ◽

Wide Range ◽

Lower Mobility

Rehabilitation robots are increasingly being developed in order to be used by injured people to perform exercise and training. As these exercises do not need wide range movements, some parallel robots with lower mobility architecture can be an ideal solution for this purpose. This paper presents the design of a new four degree-of-freedom (DOF) parallel robot for knee rehabilitation. The required four DOFs are two translations in a vertical plane and two rotations, one of them around an axis perpendicular to the vertical plane and the other one with respect to a vector normal to the instantaneous orientation of the mobile platform. These four DOFs are reached by means of two RPRR limbs and two UPS limbs linked to an articulated mobile platform with an internal DOF. Kinematics of the new mechanism are solved and the direct Jacobian is calculated. A singularity analysis is carried out and the gained DOFs of the direct singularities are calculated. Some of the singularities can be avoided by selecting suitable values of the geometric parameters of the robot. Moreover, among the found singularities, one of them can be used in order to fold up the mechanism for its transportation. It is concluded that the proposed mechanism reaches the desired output movements in order to carry out rehabilitation maneuvers in a singularity-free portion of its workspace.

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Assessment of point and line contact stiffness formulations leading to the initiation of hammering type brake squeal

Noise Control Engineering Journal ◽

10.3397/1/376915 ◽

2021 ◽

Vol 69 (2) ◽

pp. 146-161

Author(s):

Osman Taha Sen ◽

Rajendra Singh

Keyword(s):

Normal Force ◽

Contact Stiffness ◽

Point Contact ◽

Vertical Plane ◽

Degree Of Freedom ◽

Rotational Degree ◽

Line Contact ◽

Brake Squeal ◽

Minimal Order ◽

Force Vector

This article proposes a refined nonlinear mathematical model to conceptually investigate the brake pad kinematics and dynamics in order to reveal certain important aspects that have been ignored in prior studies. In particular, the proposed model is formulated as a three degree-of-freedom mass positioned on a rigid frictional surface moving at constant velocity. The mass is assumed to make planar motion in vertical plane, two translations and one rotation. The interfacial contact is first examined by a point contact model with linear translational springs at edges and then the line contact is defined over the entire interface. Furthermore, kinematic and clearance nonlinearities are included. The nonlinear governing equations with point contacts at edges are numerically solved at certain angular arrangements of normal force vectors. Then, the line contact interface is solved again for the same normal force vector arrangements. Comparison reveals that the line contact approach provides more meaningful results. Finally, a linearized system model and the existence of quasi-static sliding motion are examined over a range of the normal force vector arrangements. Overall, inclusion of the rotational degree of freedom in the source model is crucial and the importance of pad-disc separation is clearly explained by the proposed formulation. This leads to a better understanding of the hammering type brake squeal source mechanisms while overcoming the limitation of prior minimal order models

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A High Performance Energy Analyzer for Use in Electron Scanning Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061975 ◽

1969 ◽

Vol 27 ◽

pp. 14-15

Author(s):

A. V. Crewe ◽

M. Isaacson ◽

D. Johnson

Keyword(s):

High Performance ◽

Vertical Plane ◽

Median Plane ◽

Electron Gun ◽

Uniform Field ◽

Loss Mechanism ◽

Electron Scanning Microscopy ◽

Sector Type ◽

Double Focusing ◽

Electron Energy Loss

A double focusing magnetic spectrometer has been constructed for use with a field emission electron gun scanning microscope in order to study the electron energy loss mechanism in thin specimens. It is of the uniform field sector type with curved pole pieces. The shape of the pole pieces is determined by requiring that all particles be focused to a point at the image slit (point 1). The resultant shape gives perfect focusing in the median plane (Fig. 1) and first order focusing in the vertical plane (Fig. 2).

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The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168621 ◽

1994 ◽

Vol 52 ◽

pp. 178-179

Author(s):

Nancy R. Wallace ◽

Craig C. Freudenrich ◽

Karl Wilbur ◽

Peter Ingram ◽

Ann LeFurgey

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Time Course ◽

Vertical Plane ◽

Mantle Cavity ◽

Qualitative Assessment ◽

Calcium Deposition ◽

Free Swimming ◽

Freeze Dried ◽

Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

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