scholarly journals Underwater Gripper using Distributed Network and Adaptive Control

2020 ◽  
Vol 2 (1) ◽  
pp. 43-49
Author(s):  
Dr. A. Dinesh Kumar
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Distributed Network ◽  
End Effector ◽  
Autonomous Manipulation ◽  
Moving Base ◽  
Industrial Maintenance ◽  
Inspection Tasks ◽  
Almost All ◽  
Marine Engineers ◽  
Complicated Configuration

Underwater identification and grasping of objects is a major challenge faced by the marine engineers even today. Nowadays, almost all underwater operations are either autonomous or tele-operated. In fact remotely operated vehicles (ROVs) are used to deal with inspection tasks and industrial maintenance whenever there is need for intervention. However, the field of autonomous underwater vehicle (AUV) is a blooming filed with research involving proper moving base control and forces interacting which leads to complicated configuration. Hence the presented work is focused implementation of end-effector with appropriate control and signal processing resulting in autonomous manipulation of movement under water.

scholarly journals A measure of control of submerging and surfacing of an Autonomous underwater vehicle for exploring underwater of rivers

2020 ◽  
Vol 3 (SI1) ◽  
pp. SI151-SI156
Author(s):  
Le Khanh Tan ◽  
Tran Ngoc Huy ◽  
Pham Huy Hoang
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Fixed Position ◽  
Time Service ◽  
Main Factors ◽  
Underwater Tunnel ◽  
Save Energy ◽  
Almost All ◽  
Great Energy ◽  
Selection Of

Autonomous underwater vehicle (AUV) known, as a special purpose underwater research vehicle (SPURV) is really a pocket submarine that could be used in multipurpose such as meteorology, probing the pollution of stream, military spying, exploring an underwater tunnel or wrecked ships and other purposes. With the reason of the power of battery inside of AUV is limited, the aim of this paper is to represent an effect way of control the submerging and surfacing of an AUV in order to save energy for a longer time service or a deeper and further expedition under water. In fact, there are so many ways for saving energy of the battery of AUV and in this paper, the selection of keeping permanently the horizontal direction of the AUV in any operation as the situation of a real submarine is applied. The diving and surfacing of AUV are consigned to the motor of the pump that consumes a little of energy to keep the proportion of the weight and the Archimedes force by pumping water inside or outside of the AUV. The selection of volume of pumped water is considered as a dynamic ballast mass for maintaining the horizontal equilibrium of the AUV at the time of submerging and surfacing. In the other hand, the controlling of the gravity point of AUV for maintaining a fixed position of gravity of the AUV when submerging and surfacing are the main factors of the paper that is also investigated in this paper. Finally, the motor of the propeller or thruster that always spends a great energy has committed only for forward or backward motion of the AUV. In this measure, the motor of thruster does not confronted with a great consummation of energy when submerging and surfacing in an oblique direction as almost all popular measures of control of AUV.

Control of a mobile robotic manipulator: a combined design approach

2018 ◽  
Author(s):  
Martín Crespo ◽  
Matías Nacusse ◽  
Sergio Junco ◽  
Vitalram Rayankula ◽  
Pushparaj Mani Pathak
Keyword(s):  
Arm Movement ◽  
Backstepping Technique ◽  
Energy Shaping ◽  
End Effector ◽  
Dc Motors ◽  
Operational Space ◽  
Control Actions ◽  
Moving Base ◽  
The One ◽  
Mobile Base

"This paper focuses on the problem of reducing via control actions the interaction between the mobile platform and the arm in a mobile robot equipped with a redundant planar manipulator. It is solved maintaining the mobile base as immobile as possible once it has been moved to a desired position, which serves to a double purpose. On the one hand, it helps keeping fixed the workspace of the manipulator, as predefined in the world coordinates, in order for the end-effector being able to reach the points where it has to perform its tasks. On the other hand, as this reduces the disturbances that the otherwise moving base would introduce on the arm movement, this serves to improve the precision in the execution of whatever task the end-effector has to perform. The problem is solved via a combination of operational space control to solve the arm tip trajectory tracking problem and energy-shaping and damping assignment to restrict the movement of the mobile base. The latter is achieved using a backstepping technique in the Bond Graph domain which emulates dissipation and stiffness at the base wheels coordinates through the control of the DC motors actuating them. Simulation results show the good performance of the control system."

A Surface Interpolation Scheme Based on the Theory of Conjugate Surfaces

1994 ◽  
Author(s):  
Chih-Hsin Chen
Keyword(s):  
Robot Motion ◽  
Interpolation Point ◽  
Interpolation Scheme ◽  
Base Plane ◽  
End Effector ◽  
Surface Interpolation ◽  
Surface Patches ◽  
Moving Base ◽  
Conjugate Surfaces ◽  
Interpolation Functions

Abstract A surface interpolation scheme is described for interpolating an array of knot points and normals. The scheme is based on the generation of interpolation surface patches by envelopment of a moving base plane which is fixed in the end effector of a robot of two revolute pairs and one prismatic pair. The initial values, the control values, and the interpolation functions of the robot motion are discussed. The equations for determining the geometrical values of an interpolation point are derived with the aid of the theory of conjugate surfaces, and are arranged in order of the corresponding algorithm. The continuity between neighboring interpolation surface patches is proved to be C1.5. The feasibility of improving the continuity by adjusting the control values of the robot motion is investigated.

scholarly journals On the Structural Synthesis of Multi-Fingered Hands

2000 ◽  
Author(s):  
Jyh-Jone Lee ◽  
Chun-Po Chen
Keyword(s):  
Contact Geometry ◽  
Human Hand ◽  
Robot Arm ◽  
Structural Synthesis ◽  
End Effector ◽  
New Approach ◽  
Mechanical Hand ◽  
Autonomous Manipulation ◽  
Force Closure ◽  
Human Hands

Abstract Compared to the serial type of six-freedom robot arm attached with an end-effector, the multi-fingered hand system can provide more dexterity and versatility in the field of autonomous manipulation tasks. Designs of multi-fingered hands can be found in the literature, to name a few, Mechanical Hand by Skinner [13], Multi-jointed Finger System by Okada [6], Stanford/JPL Hand (or Salisbury Hand) [11], Utah-MIT Hand [3], and NTU-1 Hand [5]. Generally, these mechanical hand systems have been designed to simulate a subset function of human hands. The structures of these systems basically resemble the skeleton of human hand and are constructed by designers’ intuition. Not much literature addressed about the structural synthesis of multi-fingered hands. This paper presents a new approach for the structural synthesis of multi-fingered hands. It takes into account both the total mobility and the force closure criterion of the system. Based upon the Grübler’s mobility equation, relations regarding the numbers of fingers, contact geometry, and object freedoms are established. Subsequently, by applying the force closure criterion, the total number of possible multi-fingered hands with given mobility are synthesized.

Dynamic Analysis of the UVMS: Effect of Disturbances, Coupling, and Joint-Flexibility on End-Effector Positioning

Robotica ◽  
2021 ◽  
pp. 1-29
Author(s):  
Umer Hameed Shah ◽  
Mansour Karkoub ◽  
Deniz Kerimoglu ◽  
Hong-Du Wang
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Added Mass ◽  
Hydrodynamic Forces ◽  
Viscous Damping ◽  
End Effector ◽  
Flexible Joint ◽  
Lagrange Formulation ◽  
System Coupling ◽  
Flexible Joint Manipulator

SUMMARY This paper investigates the dynamics of an underwater vehicle-manipulator system (UVMS) consisting of a two-link flexible-joint manipulator affixed to an autonomous underwater vehicle. The quasi-Lagrange formulation is utilized in deriving a realistic mathematical model of the UVMS considering joints’ friction, hysteretic coupling between the joints and links, and the nonlinear hydrodynamic forces acting on the system, such as added mass, viscous damping, buoyancy, drag, and vortex-induced forces. Numerical simulations are performed to demonstrate the effects of hydrodynamic forces and system coupling between the vehicle and the manipulator and the joints and the links on the precise positioning of the end effector.

Derivation of Forward and Inverse Kinematics of 8 - Degrees of Freedom Based Bio-Inspired Humanoid Robotic Arm

2014 ◽  
Vol 984-985 ◽  
pp. 1245-1252 ◽  
Author(s):  
Jayabalan Sudharsan ◽  
L. Karunamoorthy
Keyword(s):  
Elbow Joint ◽  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Learning Algorithm ◽  
Inverse Kinematic ◽  
Robotic Arm ◽  
Human Being ◽  
Robot Arm ◽  
End Effector ◽  
Almost All

Designing a humanoid robot is a complex issue and the exact resemblance of human arm movements has not been achieved in many of the previously developed robots. This paper is going to be much focused on the design of a humanoid robot arm which has a unique approach which has never been developed earlier. Even though all the robots that have been developed using 6-Degrees of Freedom (DOF) and 7-DOF can reach any point in the space, some of the orientation cannot be reached by the end effector plane effectively. So an 8-DOF freedom based robotic arm has been specially designed and developed to resemble the exact movements of the human being. This robot has 3-DOF for shoulder joint, 2-DOF for the elbow joint, and 3-DOF for the wrist with fingers as the end effector. Almost all the robots have only 1-DOF to the elbow joint but here 2-DOF has been proposed to resemble the exact movements of the human being (2-DOF at elbow) to solve the above mentioned problem. Literature reviews and design model are discussed in detail to support the proposal that has been made. Forward and inverse Kinematic relationships are also obtained for the joint link parameter. This humanoid robot arm which has been designed and developed is one of the modules of a human size humanoid robot RALA (Robot based on Autonomous Learning Algorithm).

Habitat Association of Klebsiella Species

1985 ◽  
Vol 6 (2) ◽  
pp. 52-58 ◽  
Author(s):  
Susan T. Bagley
Keyword(s):  
Drinking Water ◽  
Gastrointestinal Tract ◽  
Surface Waters ◽  
Industrial Effluents ◽  
Opportunistic Pathogen ◽  
Habitat Associations ◽  
Habitat Association ◽  
Klebsiella Species ◽  
Almost All ◽  
Polluted Waters

AbstractThe genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that “K. pneumoniae” actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae—humans, animals, sewage, and polluted waters and soils; K. oxytoca—frequent association with most habitats; K. terrigena— unpolluted surface waters and soils, drinking water, and vegetation; K. planticola—sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis—infrequently detected (primarily with humans).

SEM Cold Stage Techniques for the Observation of Vegetative and Floral Apices of Oat (Avena sativa L.) Plants

1977 ◽  
Vol 35 ◽  
pp. 590-591
Author(s):  
B. K. Kirchoff ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Critical Point ◽  
Avena Sativa ◽  
Substantial Improvement ◽  
Fresh Tissue ◽  
Cold Stage ◽  
Critical Point Drying ◽  
Almost All ◽  
Cell Collapse ◽  
Conductive Paint ◽  
Carbon Based

In attempting to use the SEM to investigate the transition from the vegetative to the floral state in oat (Avena sativa L.) it was discovered that the procedures of fixation and critical point drying (CPD), and fresh tissue examination of the specimens gave unsatisfactory results. In most cases, by using these techniques, cells of the tissue were collapsed or otherwise visibly distorted. Figure 1 shows the results of fixation with 4.5% formaldehyde-gluteraldehyde followed by CPD. Almost all cellular detail has been obscured by the resulting shrinkage distortions. The larger cracks seen on the left of the picture may be due to dissection damage, rather than CPD. The results of observation of fresh tissue are seen in Fig. 2. Although there is a substantial improvement over CPD, some cell collapse still occurs.Due to these difficulties, it was decided to experiment with cold stage techniques. The specimens to be observed were dissected out and attached to the sample stub using a carbon based conductive paint in acetone.

Electron microscopy studies of plasma-sprayed materials

1983 ◽  
Vol 41 ◽  
pp. 70-71
Author(s):  
K.R. Subramanian ◽  
A.H. King ◽  
H. Herman
Keyword(s):  
Plasma Spraying ◽  
Substrate Surface ◽  
Flame Temperature ◽  
Ceramic Coatings ◽  
Metallic Substrates ◽  
Hot Plasma ◽  
Almost All ◽  
Plasma Sprayed ◽  
Hostile Environments ◽  
Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

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