Redundant Robot: A Dynamic Performance Point of View

1992 ◽  
Author(s):  
Vittorio Marchis ◽  
Rosario Sinatra
Keyword(s):  
Dynamic Performance ◽  
Time History ◽  
Point Of View ◽  
Geometrical Parameters ◽  
Objective Functions ◽  
Redundant Robot ◽  
Redundant Robots ◽  
Performance Point ◽  
Performance Map ◽  
Principal Directions

Abstract Redundant robots find important applications in non structured environment, particularly in presence of obstacles. The number of degree of freedom (DOF) allow a choice of the configuration over range, even when the path has been planned and the constraints have been taken into account. Optimization of the time history, to be planned for the robot, can be achieved with respect to several objective functions. Following to a previous work by the Authors, the present paper analyzes the vibration eigenfrequencies, and their oscillation principal directions applied to a plane 3R manipulator, over its entire workspace. A dynamic performance map, correlated to the robot geometrical parameters, has been calculated via Monte Carlo method.

How to Design and Operate Quiet Centrifugal Compressor System

2000 ◽  
Author(s):  
Roman W. Motriuk
Keyword(s):  
Centrifugal Compressor ◽  
Dynamic Performance ◽  
Point Of View ◽  
Design Parameters ◽  
Clear Understanding ◽  
System Failures ◽  
Performance Point ◽  
Vibration Problems ◽  
And Performance ◽  
Fatigue Failures

Historically, designs of centrifugal compressor systems focused on the aerodynamic and performance aspects. Noise, pulsation, and vibration phenomena were rarely considered. Recent applications of high flow and high power centrifugal compressors require that this approach be changed. Several transmission system failures, in different gas transmission companies, were documented. They included fatigue failures of the compressor components, piping attachments, and, in some instances, pipework shell failures. As a result, numerous investigations were carried out. While the compressors were adequately designed from the aerodynamic performance point of view, they appeared to act as dynamic generators, producing excessive noise, pulsation, and vibration levels even when operated well within their design parameters. It was found that neither the designers nor equipment users had a clear understanding on how to practically analyse and mitigate such dynamic phenomena. The objective of this study is to briefly explain possible sources of the observed problems in the hope that such explanation might provide a means for preventing or minimising noise and pulsation generation in centrifugal machines. The study is based on the author’s experience in mitigating pulsation/noise and vibration problems mainly in the single stage natural gas centrifugal compressor systems. The study briefly describes differences in operation between vaned and vaneless diffuser compressors. It considers pipework and its influence on the compressor dynamic performance, and addresses some aspects of the compressor design in both aerodynamic and acoustic areas. Furthermore, it gives several practical methods to mitigate high frequency pulsation and vibration problems. Most of the approaches suggested here were implemented in the field and evaluated either by the author or others.

The Potential of The Hotel Industry In Pandemic Era Based On Finance Performance Point Of View, Case Study: Indonesia

2021 ◽  
Vol 1 (1) ◽  
pp. 111-123
Author(s):  
Anton Effendi ◽  
◽  
Bambang Hadi Prabowo
Keyword(s):  
Hospitality Industry ◽  
Stock Exchange ◽  
Hotel Industry ◽  
Secondary Data ◽  
Reliable Data ◽  
Point Of View ◽  
Threshold Autoregressive ◽  
Performance Point ◽  
Occupancy Rates

This article aims to investigate and analyze the potential of the hospitality industry by comparing the potential occupancy rates and hotel revenues of foreign and domestic tourists. This investigation uses an investigation of company data obtained from reports from hotel companies throughout Indonesia which are listed on the Indonesia Stock Exchange and secondary data obtained from world banks and other reliable data. This study uses behavioral data analysis using Threshold Autoregressive from 2000 to 2019. It was found that domestic tourists are a new hope that needs to be considered in surviving and restoring the hospitality industry after being exposed to the COVID-19 pandemic which has led hotel companies. temporarily closed operations and part of the hotel went bankrupt. Optimization of domestic tourists allowed the hotel industry to develop rapidly after the Covid-19 pandemic ended.

scholarly journals Comparative study on the redundancy of mobile single- and dual-arm robots

2016 ◽  
Vol 13 (6) ◽  
pp. 172988141666678
Author(s):  
Hongxing Wang ◽  
Ruifeng Li ◽  
Yunfeng Gao ◽  
Chuqing Cao ◽  
Lianzheng Ge
Keyword(s):  
Rate Control ◽  
Control Algorithm ◽  
Redundant Robot ◽  
Motion Models ◽  
Redundant Robots ◽  
Operational Space ◽  
Rate Control Algorithm ◽  
Simulation Results ◽  
Dual Arm Robot ◽  
Dual Arm

A whole resolved motion rate control algorithm designed for mobile dual-arm redundant robots is presented in this article. Based on this algorithm, the end-effector movements of the dual arms of the mobile dual-arm redundant robot can be decomposed into the movements of the two driving wheels of the differential driving platform and the movements of the dual-arm each joint of this robot harmoniously. The influence of the redundancies of the single- and dual-arm robots on the operation based on the fixed- and differential-driving platforms, which are then based on the whole resolved motion rate control algorithm, is studied after building their motion models. Some comparisons are made to show the advantages of this algorithm on the entire modeling of the complicated robotic system and the influences of the redundancy. First, the comparison of the simulation results between the fixed single-arm robot and the mobile single-arm robot is presented. Second, a comparison of the simulation results between the mobile single-arm robot and the mobile dual-arm robots is shown. Compared with the mobile single-arm robot and the fixed dual-arm robot based on this algorithm, the mobile dual-arm robot has more redundancy and can simultaneously track and operate different objects. Moreover, the mobile dual-arm redundant robot has better smoothness, more flexibility, larger operational space, and more harmonious cooperation between the two arms and the differential driving platform during the entire mobile operational process.

scholarly journals Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions

2018 ◽  
Vol 8 (8) ◽  
pp. 1243 ◽  
Author(s):  
Iman Mohseni ◽  
Hamidreza Lashkariani ◽  
Junsuk Kang ◽  
Thomas Kang
Keyword(s):  
Ground Motion ◽  
Dynamic Performance ◽  
Time History ◽  
Bending Moment ◽  
Element Model ◽  
Structural Performance ◽  
Far Field ◽  
Inelastic Behavior ◽  
Earthquake Loads ◽  
Arch Bridges

This study assessed the structural performance of reinforced concrete (RC) arch bridges under strong ground motion. A detailed three-dimensional finite element model of a 400 m RC arch bridge with composite superstructure and double RC piers was developed and its behavior when subjected to strong earthquakes examined. Two sets of ground motion records were applied to simulate pulse-type near- and far-field motions. The inelastic behavior of the concrete elements was then evaluated via a seismic time history analysis. The concept of Demand to Capacity Ratios (DCR) was utilized to produce an initial estimate of the dynamic performance of the structure, emphasizing the importance of capacity distribution of force and bending moment within the RC arch and the springings and piers of the bridge. The results showed that the earthquake loads, broadly categorized as near- and far-field earthquake loads, changed a number of the bridge’s characteristics and hence its structural performance.

scholarly journals Measuring Productivity and Efficiency of Seaports in India using DEA technique

2018 ◽  
Vol 2 (3) ◽  
pp. 153 ◽  
Author(s):  
Jeronimo Guilherme Remigio MONTEIRO
Keyword(s):  
Design Research ◽  
Point Of View ◽  
Main Role ◽  
Data Envelopment ◽  
Bayesian Techniques ◽  
Functional Specification ◽  
Use Of Data ◽  
Performance Point ◽  
Port System

Aim: In this paper we are looking at the seaports (in India called ‘major ports’) from the context of its trade and India’s strategic importance in trade world after the initiation of economic reforms in 1991. It empirically estimates the levels of productivity and efficiency of seaports in India. This paper applies DEA technique to assess productivity and efficiency of seaports in India. Design/Research methods: DEA technique is extensively used in the literature of economics to provide measures of firms’ technical efficiency. These measures rank the firms by looking at their apparent performances over a period of time. DEA is a frontier model which is non-parametric since no functional specification or form is required to be mentioned. Conclusions/Findings: The DEA results as discussed and reported in the paper have shown how Indian ports are performing over the years. This investigation alone is not sufficient to develop a benchmark in the port system of India. Rather it will do well to have a closer look at the Indian ports from the physical and financial performance point of view. This study made use of data envelopment analysis (DEA) to generate what we call an efficiency benchmarks and assessment of the Indian ports sector. With this modest attempt to investigate the port sector of India several issues are in the open one can further analyze and come to desired conclusions. Originality/value of the paper: The main role of a port is to transfer goods between two transport modes. As far as Indian ports are concerned, there are few studies with regard to productivity and efficiency of the port sector. Since, there is an attempt in recent years to overhaul the infrastructure sectors of the Indian economy and especially seaports. There is a need to look at issues in port sector as well. Productivity and efficiency concerns should be the main aspect of the benchmarking of the performance of today’s Indian ports. Limitations of the research: Second stage DEA, distance function approach, Bayesian techniques, Carlo Monte techniques, can be alternatively used.  

Dynamics of redundant robots – inverse solutions

Robotica ◽  
1986 ◽  
Vol 4 (4) ◽  
pp. 263-267 ◽  
Author(s):  
Ronald L. Huston ◽  
Timothy P. King
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Solution Algorithm ◽  
Redundant Robot ◽  
Redundant Robots ◽  
Revolute Joints ◽  
Inverse Kinematics Problem ◽  
Inverse Solutions ◽  
Natural Dynamics ◽  
Least Energy

SUMMARYThe dynamics of “simple, redundant robots” are developed. A “redundant” robot is a robot whose degrees of freedom are greater than those needed to perform a given kinetmatic task. A “simple” robot is a robot with all joints being revolute joints with axes perpendicular or parallel to the arm segments. A general formulation, and a solution algorithm, for the “inverse kinematics problem” for such systems, is presented. The solution is obtained using orthogonal complement arrays which in turn are obtained from a “zero-eigenvalues” algorithm. The paper concludes with an assertion that this solution, called the “natural dynamics solution,” is optimal in that it requires the least energy to drive the robot.

CAREER CAPITAL. CONCEPTUAL APPROACHES

2021 ◽  
pp. 78-88
Author(s):  
Irina P. Popova ◽  
Keyword(s):  
Professional Training ◽  
Management Practices ◽  
Theory Development ◽  
Point Of View ◽  
Organizational Strategies ◽  
Social And Cultural Capital ◽  
Career Capital ◽  
Principal Directions ◽  
Interdisciplinary Interaction ◽  
Career Research

This article considers approaches to studying the career capital in the interdisciplinary career studies from the point of view of the creating conditions issues for professional development of employees. The concept was formed within the framework of the interdisciplinary career research, based on the concepts of the human, social and cultural capital, as one of the tools for understanding new processes in the field of labor. The content of those processes determines, among other things, the growing variety of career models and the need to adapt them to organizational strategies. Attention is focused on studying those concepts in two principal directions: considering it as a tool for management practices in modern organizations and considering it in the perspective of the career theory development. Conclusions are drawn that approaches to considering career capital are based on interdisciplinary interaction and understanding of the multilevel context of a career in the organizations research. Groups of environmental infrastructure factors are identified for the development of professional promotion opportunities; professional training of employees; individual career success.

Effects of Actuators and Sensors Position on Independent Modal Control Performance

2012 ◽  
Author(s):  
Simone Cinquemani ◽  
Ferruccio Resta
Keyword(s):  
Natural Frequencies ◽  
Acoustic Noise ◽  
Dynamic Performance ◽  
Active Vibration Control ◽  
Spillover Effects ◽  
Point Of View ◽  
Control Technique ◽  
Modal Control ◽  
Sensors And Actuators ◽  
Active Vibration

Independent modal control technique allows to change the eigenvalues of a system, without changing its eigenvectors. From a mechanical point of view, it means it is possible to modify the natural frequencies and the damping of a n-DoF system, letting modal shapes unchanged. Independent modal control can be profitably used in active vibration control increasing the damping of the system without changing its natural frequencies and vibration modes. A control of this type can improve the dynamic performance, reduce the vibratory phenomenon (and the resulting acoustic noise) and increase the fatigue strength of the system. This work demonstrates how the performance of the control depends on the number and position of sensors and actuators used besides, obviously, on the reduced model used to synthesize the control itself. Finally the paper suggests a simple optimum function to minimize the spillover effects due to unmodeled modes. Theoretical aspects are supported by numerical simulations.

Investigations on Optimal Design of a U-Tube Steam Generator

2010 ◽  
Author(s):  
Hui-min Qin ◽  
Chang-qi Yan ◽  
Meng Wang ◽  
Shi-jing He
Keyword(s):  
Optimal Design ◽  
Steam Generator ◽  
Optimization Techniques ◽  
Point Of View ◽  
Geometric Constraints ◽  
Optimal Designs ◽  
Optimal Method ◽  
Obvious Effect ◽  
Pressurized Water ◽  
Performance Point

Steam generator is one of the key equipments in the pressurized water reactor, from the performance point of view, it is necessary to apply optimization techniques to the design of the steam generator. In this work, the optimal designs of a U-tube steam generator (UTSG), taking minimization of the total volume and net weight as objective respectively, are carried out by considering thermohydraulic and geometric constraints using a complex-genetic algorithm (CGA). And the sensitivities of some parameters which influence the total volume and net weight of UTSG are also analyzed. Under the condition of constant secondary thermalhydraulic parameters of the steam generator, the optimal design indicates an obvious effect taking either the overall volume or the total weight of the steam generator as the objective. The optimization results show that the proposed optimal method is feasible and effective. And the results of optimal designs and sensitivity analysis would provide guidance in the engineering design of UTSG.

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