scholarly journals Research Map of Robotics. What we study for robotics. Dynamic Manipulability of Unconstrained Underwater Robot Manipulator Considered the Fluid Drag Force.

1996 ◽  
Vol 14 (3) ◽  
pp. 415-421
Author(s):  
Yasuyuki Adachi ◽  
Kazuo Yoshida
Keyword(s):  
Drag Force ◽  
Robot Manipulator ◽  
Underwater Robot ◽  
Fluid Drag

Fluid Drag Force Production and Motion Control of an Aquarobot Manipulator by Ejecting Air Bubbles

1990 ◽  
Vol 2 (5) ◽  
pp. 351-357
Author(s):  
Masakazu Ogasawara ◽  
◽  
Fumio Hara ◽  
Keyword(s):  
Drag Force ◽  
High Speed ◽  
Robot Manipulator ◽  
Force Production ◽  
Air Bubbles ◽  
Air Bubble ◽  
Fluid Forces ◽  
Fluid Drag ◽  
Force Reduction ◽  
Controlled Flow

The motion of a robot manipulator submerged in water is strongly affected by fluid forces, and it is an important technique to avoid their influence on the motion of an aquarobot manipulator to achieve high-speed, precise motion. This paper deals with extension of the technique of air bubble ejection from the manipulator surface, i.e., the mechanisms of reduction of drag force by air bubble ejection and its effects on the control of the aquarobot manipulator. Using a two-degree-of-freedom and two-joint manipulator, experiments were performed and the following major results were obtained: (1) There exists a particular pattern of air bubble ejection for reduction fluid drag force acting on the manipulator and it resulted in reduction of drag force by 25% compared to that for no air bubble ejection. (2) There exists a particular pattern of air bubble ejection that brought a 40% reduction of the control torque required for compensating the fluid drag force. (3) The major mechanisms for drag force reduction were found to be the controlled flow pattern around the manipulator formed by ejecting air bubbles. However, it is noted that these effects of air bubble ejection were dependent on the mode of manipulator motion.

A Potential 4-D Fingertip Force Sensor for an Underwater Robot Manipulator

2010 ◽  
Vol 35 (3) ◽  
pp. 574-583 ◽  
Author(s):  
Qiaokang Liang ◽  
Dan Zhang ◽  
Quanjun Song ◽  
Yunjian Ge
Keyword(s):  
Robot Manipulator ◽  
Force Sensor ◽  
Underwater Robot ◽  
Fingertip Force

Adaptive VSS Control with Deformable Sliding Surfaces for Underwater Robot Manipulator Drives

2013 ◽  
Vol 46 (33) ◽  
pp. 257-261
Author(s):  
Vasily E. Markin ◽  
Alexandr A. Dyda ◽  
Dmitry A. Oskin
Keyword(s):  
Robot Manipulator ◽  
Underwater Robot ◽  
Sliding Surfaces

Fluid Drag on a Sphere Rolling in a Tube

1967 ◽  
Vol 34 (3) ◽  
pp. 538-540
Author(s):  
A. B. Bauer ◽  
R. A. DuPuis
Keyword(s):  
Incompressible Fluid ◽  
Drag Force ◽  
Reynolds Numbers ◽  
Vertical Tube ◽  
Experimental Results ◽  
Constant Speed ◽  
Sphere Diameter ◽  
Fluid Drag ◽  
Drag Law ◽  
Good Agreement

The incompressible fluid drag force on a sphere rolling at constant speed in a closed-end tube has been analyzed for the case where the tube inside diameter is only slightly larger than the sphere diameter. One drag law is found for Reynolds numbers much less than 75π/4λ1/2, where λ is a parameter defined by the sphere and tube diameters. A second drag law is found for Reynolds numbers much larger than 75π/4λ1/2. Experimental results show good agreement with these drag laws. The first law is almost identical with the results of Christopherson and Dowson, and of McNown, et al., for a sphere falling in a vertical tube.

scholarly journals Nonlinear Oscillations Induced by Follower Forces in Prestressed Clamped Rods Subjected to Drag

2018 ◽  
Vol 13 (12) ◽  
Author(s):  
Soheil Fatehiboroujeni ◽  
Arvind Gopinath ◽  
Sachin Goyal
Keyword(s):  
Drag Force ◽  
Nonlinear Oscillations ◽  
Critical Force ◽  
Geometric Constraints ◽  
Elastic Instability ◽  
Compatibility Conditions ◽  
Nonlinear Buckling ◽  
Fluid Drag ◽  
Follower Forces ◽  
Instability Energy

Elastic-driven slender filaments subjected to compressive follower forces provide a synthetic way to mimic the oscillatory beating of biological flagella and cilia. Here, we use a continuum model to study the dynamical, nonlinear buckling instabilities that arise due to the action of nonconservative follower forces on a prestressed slender rod clamped at both ends and allowed to move in a fluid. Stable oscillatory responses are observed as a result of the interplay between the structural elastic instability of the inextensible slender rod, geometric constraints that control the onset of instability, energy pumped into the system by the active follower forces, and motion-driven fluid dissipation. Initial buckling instabilities are initiated by the effect of the follower forces and inertia; fluid drag subsequently allows for the active energy pumped into the system to be dissipated away and results in self-limiting amplitudes. By integrating the equations of equilibrium and compatibility conditions with linear constitutive laws, we compute the critical follower forces for the onset of oscillations, emergent frequencies of these solutions, and the postcritical nonlinear rod shapes for two forms of the drag force, namely linear Stokes drag and quadratic Morrison drag. For a rod with fixed inertia and drag parameters, the minimum (critical) force required to initiate stable oscillations depends on the initial slack and weakly on the nature of the drag force. Emergent frequencies and the amplitudes postonset are determined by the extent of prestress as well as the nature of the fluid drag. Far from onset, for large follower forces, the frequency of the oscillations can be predicted by evoking a power balance between the energy input by the active forces and the dissipation due to fluid drag.

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