Optimal Architecture Planning of Modules for Reconfigurable Manipulators

Robotica ◽  
2020 ◽  
pp. 1-15
Author(s):  
Anubhav Dogra ◽  
Srikant Sekhar Padhee ◽  
Ekta Singla
Keyword(s):  
Dynamic Performance ◽  
Equivalent System ◽  
Complete Structure ◽  
Joint Torques ◽  
Complex Shapes ◽  
Reconfigurable Manipulators

SUMMARY Modules are requisite for the realization of modular reconfigurable manipulators. The design of modules in literature mainly revolves around geometric aspects and features such as lengths, connectivity and adaptivity. Optimizing and designing the modules based on dynamic performance is considered as a challenge here. The present paper introduces an Architecture-Prominent-Sectioning (APS) strategy for the planning of architecture of modules such that a reconfigurable manipulator possesses minimal joint torques during its operations. Proposed here is the transferring of complete structure into an equivalent system, perform optimization and map the resulting arrangement into possible architecture. The strategy has been applied on a set of modular configurations considering three-primitive-paths. The possibility of getting advanced/complex shapes is also discussed to incorporate the idea of a modular library.

Dynamic balancing of the cleaning unit used in agricultural thresher using a non-dominated sorting Jaya algorithm

2020 ◽  
Vol 37 (5) ◽  
pp. 1849-1864
Author(s):  
Prem Singh ◽  
Himanshu Chaudhary
Keyword(s):  
Optimization Problem ◽  
Dynamic Performance ◽  
A Priori ◽  
Center Of Mass ◽  
Equivalent System ◽  
Jaya Algorithm ◽  
Content Type ◽  
Optimum Parameters ◽  
Design Variables ◽  
Adams Software

Purpose This paper aims to propose a dynamically balanced mechanism for cleaning unit used in agricultural thresher machine using a dynamically equivalent system of point masses. Design/methodology/approach The cleaning unit works on crank-rocker Grashof mechanism. This mechanism can be balanced by optimizing the inertial properties of each link. These properties are defined by the dynamic equivalent system of point masses. Parameters of these point masses define the shaking forces and moments. Hence, the multi-objective optimization problem with minimization of shaking forces and shaking moments is formulated by considering the point mass parameters as the design variables. The formulated optimization problem is solved using a posteriori approach-based algorithm i.e. the non-dominated sorting Jaya algorithm (NSJAYA) and a priori approach-based algorithms i.e. Jaya algorithm and genetic algorithm (GA) under suitable design constraints. Findings The mass, center of mass and inertias of each link are calculated using optimum design variables. These optimum parameters improve the dynamic performance of the cleaning unit. The optimal Pareto set for the balancing problem is measured and outlined in this paper. The designer can choose any solution from the set and balance any real planar mechanism. Originality/value The efficiency of the proposed approach is tested through the existing cleaning mechanism of the thresher machine. It is found that the NSJAYA is computationally more efficient than the GA and Jaya algorithm. ADAMS software is used for the simulation of the mechanism.

scholarly journals On the Redundant-Drive Backlash-Free Robotic Mechanisms

1993 ◽  
Vol 115 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Sun-Lai Chang ◽  
Lung-Wen Tsai
Keyword(s):  
Dynamic Performance ◽  
End Effector ◽  
Joint Torques ◽  
Performance Requirements ◽  
Compliance Problem ◽  
Under Construction ◽  
Fail Safe ◽  
Gear Meshes ◽  
Redundant Drive ◽  
Innovative Concept

In this paper, we introduce a new and innovative concept for the control of backlash in gear-coupled robotic mechanisms. The concept utilizes redundant unidirectional drives to assure positive coupling of gear meshes at all times. Based on this concept, a methodology for the enumeration of admissible redundant-drive backlash-free robotic mechanisms has been established. Some typical two- and three-DOF mechanisms have been sketched. Furthermore, actuator torques have been derived as functions of either joint torques or end-effector dynamic performance requirements. A redundantly driven manipulator has the fail-safe advantage in that, except for the loss of backlash control, it can continue to function when one of its actuators fails. It does not have the compliance problem associated with tendon-driven manipulators. A two-DOF backlash-free experimental arm is currently under construction to demonstrate the principle.

An Optimal Architectural Design for Unconventional Modular Reconfigurable Manipulation System

2020 ◽  
pp. 1-29
Author(s):  
Anubhav Dogra ◽  
Srikant Sekhar Padhee ◽  
Ekta Singla
Keyword(s):  
Architectural Design ◽  
Service Sector ◽  
Weight Ratio ◽  
Poly Lactic Acid ◽  
Modular Architecture ◽  
Thermoplastic Material ◽  
Joint Torques ◽  
Manipulation System ◽  
Torque Analysis ◽  
Reconfigurable Manipulators

Abstract Modular and Reconfigurable manipulators have gained popularity especially in the service sector, where the use of customized configurations has increased. Adaptable modular designs have come into advances in achieving the required configuration of a robotic manipulator. As reported in the literature, various designs of the modules mainly with conventional configurations are presented and a few are reported with unconventional adjustments. To cater the non-repetitive applications, this paper presents an optimal architectural design for unconventional parameters for customized reconfigurability. This lighter and easier to connect version is also applicable to n-DoF and unconventional robotic parameters. Architecture Prominent Sectioning (APS) strategy is proposed which assumes an architecture as a set of point masses and optimally relocate components with respect to the minimization of the joint torques. Modules are considered to be 3-D printables using poly-lactic acid (PLA), a thermoplastic material, and thus light in weight. The new modular architecture design is validated through the assemblage of conventional/unconventional configurations using two types of modules namely Heavy(H) and Light(L). Along with that, worst torque analysis for the different configurations has been done in order to provide a strategy for assembly combinations. A comparative study is presented based upon the payload to the manipulator weight ratio, involving other reported architectures.

Minimizing joint‐torques of the flexible redundant manipulator on the premise of vibration suppression

2008 ◽  
Vol 1 (4) ◽  
pp. 634-645 ◽  
Author(s):  
Zhihui Gao ◽  
Chao Yun ◽  
Yushu Bian
Keyword(s):  
Design Methodology ◽  
Vibration Suppression ◽  
Dynamic Performance ◽  
Joint Space ◽  
The Self ◽  
Redundant Manipulator ◽  
Content Type ◽  
Joint Torques ◽  
Self Motion ◽  
Practical Implications

PurposeThe purpose of this paper is to examine a new idea of vibration control which minimizes joint‐torques and suppresses vibration of the flexible redundant manipulator.Design/methodology/approachUsing the kinematics redundancy feature of the flexible redundant manipulator, the self‐motion in the joint space can be properly chosen to both suppress vibration and minimize joint‐torques.FindingsThe study shows that the flexible redundant manipulator still has the second optimization feature on the premise of vibration suppression. The second optimization feature can be used to minimize joint‐torques on the premise of vibration suppression.Research limitations/implicationsTo a flexible redundant manipulator, its joint‐torques and vibration can be reduced simultaneously via its kinematics redundancy feature.Practical implicationsThe method and algorithm discussed in the paper can be used to minimize joint‐torques and suppress vibration for the flexible redundant manipulator.Originality/valueThe paper contributes to the study on improving dynamic performance of the flexible redundant manipulator via its kinematics redundancy feature. The second optimization capability of the flexible redundant manipulator is discovered and used to both minimize joint‐torques and suppress vibration.

Transmission Electron Diffraction Analysis by Computer

1970 ◽  
Vol 28 ◽  
pp. 40-41
Author(s):  
R.A. Ploc ◽  
G.H. Keech
Keyword(s):  
Electron Diffraction ◽  
Input Data ◽  
Reciprocal Lattice ◽  
Computer Programme ◽  
Transmission Electron Diffraction ◽  
Usual Procedure ◽  
Transmission Electron ◽  
Complex Shapes ◽  
Computer Input ◽  
Diffraction Effects

An unambiguous analysis of transmission electron diffraction effects requires two samplings of the reciprocal lattice (RL). However, extracting definitive information from the patterns is difficult even for a general orthorhombic case. The usual procedure has been to deduce the approximate variables controlling the formation of the patterns from qualitative observations. Our present purpose is to illustrate two applications of a computer programme written for the analysis of transmission, selected area diffraction (SAD) patterns; the studies of RL spot shapes and epitaxy.When a specimen contains fine structure the RL spots become complex shapes with extensions in one or more directions. If the number and directions of these extensions can be estimated from an SAD pattern the exact spot shape can be determined by a series of refinements of the computer input data.

The crystallization of thin-film ceramics

1992 ◽  
Vol 50 (1) ◽  
pp. 338-339
Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Sol Gel ◽  
Processing Route ◽  
Small Areas ◽  
Ceramic Thin Films ◽  
Complex Shapes ◽  
Sol Gel Process ◽  
Ceramic Precursors ◽  
Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

Study and design of dual stator permanent magnet machine with spoke-type configurations using phase-group concentrated-coil windings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1381-1389
Author(s):  
Dezhi Chen ◽  
Chengwu Diao ◽  
Zhiyu Feng ◽  
Shichong Zhang ◽  
Wenliang Zhao
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Low Cost ◽  
Dynamic Performance ◽  
Torque Ripple ◽  
Permanent Magnet Machine ◽  
Torque Density ◽  
Phase Group ◽  
High Torque ◽  
Simulation Results

In this paper, a novel dual-stator permanent magnet machine (DsPmSynM) with low cost and high torque density is designed. The winding part of the DsPmSynM adopts phase-group concentrated-coil windings, and the permanent magnets are arranged by spoke-type. Firstly, the winding structure reduces the amount of copper at the end of the winding. Secondly, the electromagnetic torque ripple of DsPmSynM is suppressed by reducing the cogging torque. Furthermore, the dynamic performance of DsPmSynM is studied. Finally, the experimental results are compared with the simulation results.

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