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.

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.

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.

Design, kinematic and dynamic modeling of a novel tripod based manipulator

Robotica ◽  
2014 ◽  
Vol 34 (10) ◽  
pp. 2186-2204 ◽  
Author(s):  
Dan Zhang ◽  
Bin Wei
Keyword(s):  
Set Theory ◽  
Dynamic Modeling ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
General Function ◽  
Multi Objective Optimization ◽  
Gf Set ◽  
Hybrid Manipulator ◽  
New Type ◽  
Three Degrees Of Freedom

SUMMARYThis paper proposes a novel three-degrees-of-freedom (3-DOF) hybrid manipulator, 3PU*S-PU, which evolves from the general function (Gf) set theory. After discussing the advantages of this new type of hybrid manipulator, this report analyzes the kinematic and Jacobian matrix of the manipulator. Subsequently, the kinematic performances, including stiffness/compliance, and workspace, undergo analysis, followed by the multi-objective optimization of the compliance and workspace. The Lagrangian method provides the framework for briefly analyzing the dynamics of the proposed manipulator. Finally, the results of this assessment comprise a guideline for controlling the manipulator.

Brake squeal noise due to disc run-out

2007 ◽  
Vol 221 (7) ◽  
pp. 811-821 ◽  
Author(s):  
J-P Park ◽  
Y-S Choi
Keyword(s):  
Stability Analysis ◽  
Degrees Of Freedom ◽  
Experimental Results ◽  
Brake System ◽  
Brake Squeal ◽  
Friction Characteristic ◽  
Linear Friction ◽  
Brake Dynamometer ◽  
Squeal Noise ◽  
Three Degrees Of Freedom

To understand brake squeal noise, the sound and vibration of an automobile brake system were measured using a brake dynamometer. The experimental results show that an important factor in squeal generation is the run-out due to disc misalignment. A three-degrees-of-freedom model is developed for the brake system, where the run-out effect and non-linear friction characteristic are included. A stability analysis of the model was also performed to predict the generation of squeal with the modification of the brake system. The results show that squeal generation is dependent on the run-out rather than the friction characteristic between the pad and disc.

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.

Flower Robot – A Product of Biomimetic Technology

2011 ◽  
Vol 467-469 ◽  
pp. 2149-2154
Author(s):  
Nguyen Sy Hung ◽  
Phan Doan Anh Tuan ◽  
Nguyen Ngoc Phuong ◽  
Nguyen Truong Thinh
Keyword(s):  
Degrees Of Freedom ◽  
Guide Wire ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Prototype Model ◽  
Servo Motor ◽  
Practical Applications ◽  
Driven System ◽  
Flower Stem

In this paper, we propose a new prototype model of a robotic flower with active guide tendon wires which has two bending degrees of freedom. The design and fabrication methods of this flower robot are described. We also modeled this robotic flower for characteristic evaluation. Experimental results show that the model of the flower robot is reasonable for practical applications. The flower robot is a multi-degree-of-freedom (DOF) device which was developed using a tendon-driven system. Two DOF motion for the robotic stem was realized by the tendon mechanism combining flexible spring, and 1-DOF motion of flower was created by a servo motor. Each leaf uses a spring and a tendon-driven string. The proposal structure consists of flower, stem and leaves operating like a flower robot. The experimental results indicate that the proposed flower robot with active guide wire is applicable to reality. Furthermore, it is integrated with sensors to perform its functions like a flower.

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.

scholarly journals Experimental Fitting of Rotor Models by Using a Special Three-Node Beam Element

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
Mate Antali ◽  
Denes Takacs ◽  
Gabor Stepan
Keyword(s):  
Machine Tool ◽  
Nonlinear Optimization ◽  
Degrees Of Freedom ◽  
Contact Problems ◽  
Beam Element ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Initial Model ◽  
Squirrel Cage ◽  
Low Degree

In this paper, a special type of beam element is developed with three nodes and with only translational degrees-of-freedom (DOFs) at each node. This element can be used effectively to build low degree-of-freedom models of rotors. The initial model from the Bernoulli theory is fitted to experimental results by nonlinear optimization. This way, we can avoid the complex modeling of contact problems between the parts of squirrel cage rotors. The procedure is demonstrated on the modeling of a machine tool spindle.

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