Vortex-induced vibration of elastically-mounted spheres: A comparison of the response of three degrees of freedom and one degree of freedom systems

2019 ◽  
Vol 89 ◽  
pp. 142-155 ◽  
Author(s):  
Methma M. Rajamuni ◽  
Mark C. Thompson ◽  
Kerry Hourigan
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Vortex Induced Vibration ◽  
Three Degrees Of Freedom

Accelerometer correction for the dynamic analysis of damped multi-degree of freedom systems

1969 ◽  
Vol 59 (4) ◽  
pp. 1591-1598
Author(s):  
G. A. McLennan
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Exact Method ◽  
Three Degrees Of Freedom

Abstract An exact method is developed to eliminate the accelerometer error in dynamic response calculations for damped multi-degree of freedom systems. It is shown that the exact responses of a system can be obtained from the approximate responses which are conventionally calculated from an accelerogram. Response calculations were performed for two typical systems with three degrees of freedom for an assumed pseudo-earthquake. The results showed that the approximate responses may contain large errors, and that the correction developed effectively eliminates these errors.

Experimental and Numerical Hydrodynamic Modeling of an Underwater Manipulator

2001 ◽  
Author(s):  
A. Khanicheh ◽  
A. Tehranian ◽  
A. Meghdari ◽  
M. S. Sadeghipour
Keyword(s):  
Drag Coefficient ◽  
Dynamic Modeling ◽  
Hydrodynamic Model ◽  
Degrees Of Freedom ◽  
Added Mass ◽  
Hydrodynamic Modeling ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Underwater Manipulator ◽  
Three Degrees Of Freedom

Abstract This paper presents the kinematics and dynamic modeling of a three-link (3-DOF) underwater manipulator where the effects of hydrodynamic forces are investigated. In our investigation, drag and added mass coefficients are not considered as constants. In contrast, the drag coefficient is a variable with respect to all relative parameters. Experiments were conducted to validate the hydrodynamic model for a one degree-of-freedom manipulator up to a three degrees-of-freedom manipulator. Finally, the numerical and experimental results are compared and thoroughly discussed.

Design of a Teaching Robot with Three Degrees of Freedom

2012 ◽  
Vol 619 ◽  
pp. 325-328
Author(s):  
You Jun Huang ◽  
Ze Lun Li ◽  
Zhi Cheng Huang
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Degree Of Freedom ◽  
Good Repeatability ◽  
Main Components ◽  
Opening And Closing ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom ◽  
Application Prospects

A teaching robot with three degree of freedom is designed. The three degrees of freedom are: waist rotation, lifting and stretching of the arm and opening and closing of the gripper. The designs of the main components are: a mobile chassis, parallel rails, horizontal rails and manipulator. The teaching robot designed has the features of low cost, easy to regulation, good repeatability and it has good promotion and application prospects in the field of teaching.

scholarly journals Smart and Modular

2011 ◽  
Vol 133 (09) ◽  
pp. 48-51
Author(s):  
Harry H. Cheng ◽  
Graham Ryland ◽  
David Ko ◽  
Kevin Gucwa ◽  
Stephen Nestinger
Keyword(s):  
Degrees Of Freedom ◽  
Robotic System ◽  
Search And Rescue ◽  
Degree Of Freedom ◽  
Robotic Systems ◽  
Modular Robots ◽  
Modular Robot ◽  
Modular Systems ◽  
The Past ◽  
Three Degrees Of Freedom

This article discusses the advantages of a modular robot that can reassemble itself for different tasks. Modular robots are composed of multiple, linked modules. Although individual modules can move on their own, the greatest advantage of modular systems is their structural reconfigurability. Modules can be combined and assembled to form configurations for specific tasks and then reassembled to suit other tasks. Modular robotic systems are also very well suited for dynamic and unpredictable application areas such as search and rescue operations. Modular robots can be reconfigured to suit various situations. Quite a number of modular robotic system prototypes have been developed and studied in the past, each containing unique geometries and capabilities. In some systems, a module only has one degree of freedom. In order to exhibit practical functionality, multiple interconnected modules are required. Other modular robotic systems use more complicated modules with two or three degrees of freedom. However, in most of these systems, a single module is incapable of certain fundamental locomotive behaviors, such as turning.

scholarly journals A Six Degree-of-Freedom Haptic Device Based on the Orthoglide and a Hybrid Agile Eye

2006 ◽  
Author(s):  
Damien Chablat ◽  
Philippe Wenger
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Haptic Device ◽  
Parallel Mechanisms ◽  
Real Time Control ◽  
Time Control ◽  
Rotational Motions ◽  
Six Degree Of Freedom ◽  
Rotary Motor ◽  
Three Degrees Of Freedom

This paper is devoted to the kinematic design of a new six degree-of-freedom haptic device using two parallel mechanisms. The first one, called orthoglide, provides the translation motions and the second one, called agile eye, produces the rotational motions. These two motions are decoupled to simplify the direct and inverse kinematics, as it is needed for real-time control. To reduce the inertial load, the motors are fixed on the base and a transmission with two universal joints is used to transmit the rotational motions from the base to the end-effector. Two alternative wrists are proposed (i), the agile eye with three degrees of freedom or (ii) a hybrid wrist made by the assembly of a two-dof agile eye with a rotary motor. The last one is optimized to increase its stiffness and to decrease the number of moving parts.

A Compact 2 Degree of Freedom Wrist for Robot-Actuated Surgery and Other Applications

2016 ◽  
Author(s):  
Clayton L. Grames ◽  
Brian D. Jensen ◽  
Spencer P. Magleby ◽  
Larry L. Howell
Keyword(s):  
Degrees Of Freedom ◽  
Rolling Contact ◽  
Degree Of Freedom ◽  
High Part ◽  
Swept Volumes ◽  
Manufacturing Methods ◽  
Traditional Manufacturing ◽  
Swept Volume ◽  
Three Degrees Of Freedom ◽  
Surgical Operations

A new, compact 2 degree-of-freedom wrist mechanism suitable for robotically controlled surgical operations is presented. Current commercially available robotically controlled instruments achieve high dexterity defined by three degrees of freedom and relatively confined swept volume at just under 1 cm in diameter. Current smaller diameter instruments result in high part count and large swept volumes (less dexterity). A mesoscale rolling contact wrist mechanism is proposed as an alternative. The crossed cylinders wrist integrates two half-cylinders whose longitudinal axes are offset by 90°. The surfaces of the half cylinders have been populated with gearing that enables the two halves to roll in two directions while preventing slip. The manufacturing of the parts is demonstrated as feasible by a the layered assembly of Carbon Nanotube (CNT) structures, which can produce parts that are difficult to replicate with traditional manufacturing methods. The resulting wrist has only 2 parts and a small swept volume.

THE PREMIUM TECHNOLOGICAL DISCOVERY OF PETROLEUM

Geophysics ◽  
1946 ◽  
Vol 11 (3) ◽  
pp. 335-349
Author(s):  
E. E. Rosaire
Keyword(s):  
United States ◽  
Continental Shelf ◽  
Degrees Of Freedom ◽  
The United States ◽  
Technological Advance ◽  
Degree Of Freedom ◽  
Widespread Application ◽  
Primary Motivation ◽  
The Past ◽  
Three Degrees Of Freedom

Premium technological discovery volume is that achieved in excess of the volume to be anticipated on the basis of price alone and which can be attributed solely to technological advance. Three degrees of freedom, area, method, and objective, are recognized for the prospector, and these are fixed by choice in any prospecting venture. Continued operation with these three degrees fixed inevitably leads to diminishing returns and, finally, to marginal operations wherein price becomes the primary motivation. Under such conditions in the past, unfixing even one degree of freedom has led to marked surges in the discovery rate, i.e., to premium technological discovery. Such discovery surges have occurred more than once in the same petroleum province and, not infrequently, the magnitude of the surge has increased rather than decreased with time. Considerations are presented for a return to premium technological discovery within the United States. Such a return for the method now in most general use, the reflection seismograph, can be expected to follow from unfixing the area degree of freedom through initiating prospecting along the continental shelf. However, such a return for prospecting as a whole, and probably of even greater magnitude, can be anticipated to follow from unfixing the method degree of freedom through widespread application of novelty in prospecting methods.

Multi-Degree-of-Freedom Modeling of Mechanical Snubbing Systems

2011 ◽  
Author(s):  
Sudhir Kaul
Keyword(s):  
Experimental Data ◽  
Data Collection ◽  
Rigid Body ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Rigid Frame ◽  
Identification Technique ◽  
Simulation Results ◽  
Stiffness And Damping ◽  
Three Degrees Of Freedom

This paper presents a multi-degree-of-freedom model for the analysis of mechanical snubbing in elastomeric isolators. The model uses a system of elastomeric isolators and snubbers to assemble a rigid body with three degrees-of-freedom to a rigid frame. The isolators are supplemented by the snubbing system so as to limit the displacement of the rigid body in all three directions of motion when the system undergoes transient loading or overloading conditions. The model is piecewise non-linear and uses normalized Bouc-Wen elements in order to capture inherent hysteresis of the elastomeric isolators and the snubbing system as well as the transition in stiffness and damping properties resulting due to inherent coupling between the isolators and the snubbing system. Separate elements are used to model the enhanced stiffness resulting from the snubbing system in the translational directions of motion. A set of elastomeric isolators and snubbing systems is used for data collection, characterization and model validation. The data collection is carried out at multiple strain amplitudes and strain rates. A conventional least squares based parameter identification technique is used for characterization. The completely characterized model is then used for simulating the response of the rigid body and the simulation results are compared to experimental data. The simulation results are found to be in general agreement with the experimental data.

scholarly journals Research on modular implementation method of six-degree-of-freedom robotic arm

2021 ◽  
Vol 2125 (1) ◽  
pp. 012015
Author(s):  
JiaLei Su
Keyword(s):  
Degrees Of Freedom ◽  
Modular Design ◽  
Degree Of Freedom ◽  
Robotic Arm ◽  
Work Intensity ◽  
Six Degrees Of Freedom ◽  
Standard Interface ◽  
Implementation Method ◽  
Six Degree Of Freedom ◽  
Three Degrees Of Freedom

Abstract Single-joint modular design can reduce the work intensity of designers, and also can broaden the combination form of multi-degree-of-freedom robotic arm. In order to adapt to the changes of multiple degrees of freedom and multiple loads, this paper designs a series of standard modules with similar components and the same standard interface, but with different sizes only, and chooses different drive components according to the load when designing the size, and then designs the size of other parts according to the size of the drive components. The final combination of this series of modules into different degrees of freedom robotic arm, such as three degrees of freedom robotic arm, four degrees of freedom robotic arm or even six degrees of freedom robotic arm. In this paper, the most widely used six-degree-of-freedom robotic arm is used as an example, and a detailed design form is proposed.

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