Quantitative Performance Analysis of Haptic Devices With Parallelogram Subsystems

2011 ◽  
Author(s):  
Leng-Feng Lee ◽  
Xiaobo Zhou ◽  
Venkat N. Krovi
Keyword(s):  
Parallel Architecture ◽  
Theoretical Background ◽  
Haptic Device ◽  
System Level ◽  
High Definition ◽  
Haptic Devices ◽  
Serial Chain ◽  
Quantitative Performance ◽  
The Rich ◽  
The Individual

Parallel-architecture haptic devices offer significant advantages over serial-architecture counterparts in applications requiring high stiffness and high accuracy. To this end, many haptic devices have been created and deployed by modularly piecing together several serial-chain arms to form an in-parallel system. Furthermore, recent haptic devices design such as the Sensable’s PHANToM Premium line of haptic devices and Quanser’s High Definition Haptic Device (HD)2 placed the 2nd actuated joint (of a 2-DOF RR serial manipulator) at the base of the device that allowed the control of the 2nd joint through a parallelogram/fourbar structure. This design is favorable from the view point of reducing the overall weight that the first motor has to carry. However, such design choices can affect the overall system performance which depends both on the nature of the individual arms as well as their interactions. In this paper, we build on the rich theoretical background of constrained articulated mechanical systems to provide a systematic framework for formulation of system-level kinematic performance from individual-arm characteristics. Specifically, we discuss: (i) development of pertinent symbolic equations; (ii) generalization to arbitrary architectures; and (iii) combined symbolic/numeric analyses of performance, focusing on manipulability and stiffness. These aspects are illustrated using the example of Quanser High Definition Haptic Device (HD)2 — an in-parallel haptic device formed by coupling two 3-link PHANToM 1.5 type serial chain manipulators with appropriate passive joints.

A Screw-Theoretic Analysis Framework for Payload Manipulation by Mobile Manipulator Collectives

2005 ◽  
Author(s):  
Rajankumar Bhatt ◽  
Chin Pei Tang ◽  
Michel Abou-Samah ◽  
Venkat Krovi
Keyword(s):  
System Performance ◽  
Single Agent ◽  
Physical Nature ◽  
Theoretical Background ◽  
System Level ◽  
Mobile Manipulator ◽  
Test Bed ◽  
Tight Coupling ◽  
Constrained Mechanical Systems ◽  
The Individual

In recent times, there has been considerable interest in creating and deploying modular cooperating collectives of robots. Interest in such cooperative systems typically arises when certain tasks are either too complex to be performed by a single agent or when there are distinct benefits that accrue by cooperation of many simple robotic modules. However, the nature of the both the individual modules as well as their interactions can affect the overall system performance. In this paper, we examine this aspect in the context of cooperative payload transport by robot collectives wherein the physical nature of the interactions between the various modules creates a tight coupling within the system. We leverage the rich theoretical background of analysis of constrained mechanical systems to provide a systematic framework for formulation and evaluation of system-level performance on the basis of the individual-module characteristics. The composite multi-d.o.f wheeled vehicle, formed by supporting a common payload on the end-effectors of multiple individual mobile manipulator modules, is treated as an in-parallel system with articulated serial-chain arms. The system-level model, constructed from the twist- and wrench-based models of the attached serial chains, can then be systematically analyzed for performance (in terms of mobility and disturbance rejection.) A 2-module composite system example is used through the paper to highlight various aspects of the systematic system model formulation, effects of selection of the actuation at the articulations (active, passive or locked) on system performance and experimental validation on a hardware prototype test bed.

Design of a Novel Parallel Mechanism for Haptic Device

2021 ◽  
pp. 1-63
Author(s):  
Jin Lixing ◽  
Duan Xingguang ◽  
Li Changsheng ◽  
Shi Qingxin ◽  
Wen Hao ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Parallel Architecture ◽  
General Purpose ◽  
Haptic Device ◽  
Haptic Devices ◽  
Modeling And Optimization ◽  
Teleoperation Systems

Abstract This paper presents a novel parallel architecture with seven active degrees of freedom (DOFs) for general-purpose haptic devices. The prime features of the proposed mechanism are partial decoupling, large dexterous working area, and fixed actuators. The detailed processes of design, modeling, and optimization are introduced and the performance is simulated. After that, a mechanical prototype is fabricated and tested. Results of the simulations and experiments reveal that the proposed mechanism possesses excellent performances on motion flexibility and force feedback. This paper aims to provide a remarkable solution of the general-purpose haptic device for teleoperation systems with uncertain mission in complex applications.

Foundations and Introduction of Islamic Economics: Role and Trends

2020 ◽  
Vol 3 (3) ◽  
pp. 121-138
Author(s):  
Dr. Bilal Ahmad Khan
Keyword(s):  
Modern Science ◽  
Central Position ◽  
Islamic Philosophy ◽  
Moral Training ◽  
Human Ability ◽  
The Status ◽  
Distribution Of Resources ◽  
The Rich ◽  
Specific Concept ◽  
The Individual

Islamic economics based on specific concept of universe and the creation of man is contradictory to the concept adopted and accepted by modern science. Islamic economics postulates although ability and expertise is required for progress and growth but distribution of resources completely dependent on it would be cruel, inhuman and bereft of kindness, and lead to oppression. Islamic economics does not favor making human ability and expertise the fulcrum of resource distribution. It should be kind, considerate and based on justice and fairness. This is because according to Islamic philosophy, ownership is considered to be a trust from Allah which has been bestowed on the rich so that they may utilize it correctly. In Islamic economics the role of the individual, has inclinations and his aims and objectives occupy a central position and are vitally important. He is definitely a rational being but his level of rationality is not confined to the calculations of cost and profit. An individual does not want merely to obtain monetary profit and physical pleasure and leisure but he also wants and aims for something beyond what the material world has to offer. The main aim of the study is to find out the relationship between Islam and economics. In Islamic economics the comprehensive moral training of the individual, his technical and educational ability, his aims and his priorities are of primary importance. According to Islamic economics the means of acquiring wealth has the same importance as wealth itself. Dishonesty, abuse of trust and earning of wealth through fraudulent ways and means may perhaps increase the status of an individual but the society suffers because of it on the whole. This leads to an unjust and oppressive economic system.

Knowledge First

2017 ◽  
Author(s):  
J. Adam Carter ◽  
Emma C. Gordon ◽  
Benjamin W. Jarvis
Keyword(s):  
Philosophy Of Mind ◽  
Theoretical Background ◽  
Contemporary Research ◽  
Timothy Williamson ◽  
Research Themes ◽  
New Directions ◽  
Individual Contributions ◽  
The Individual

In this introductory chapter, the volume’s editors provide a theoretical background to the volume’s topic and a brief overview of the papers included. The chapter is divided into five parts: Section 1 explains the main contours of the knowledge-first approach, as it was initially advanced by Timothy Williamson in Knowledge and its Limits. In Sections 2–3, some of the key philosophical motivations for the knowledge-first approach are reviewed, and several key contemporary research themes associated with this approach in epistemology, the philosophy of mind and elsewhere are outlined and briefly discussed. The volume’s papers are divided into two broad categories: foundational issues and applications and new directions. Section 4 discusses briefly the scope and aim of the volume as the editors have conceived it, and Section 5 offers an overview of each of the individual contributions in the volume.

scholarly journals System models for resilience in gerontology: application to the COVID-19 pandemic

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Katarzyna Klasa ◽  
Stephanie Galaitsi ◽  
Andrew Wister ◽  
Igor Linkov
Keyword(s):  
The Elderly ◽  
System Level ◽  
Improve Quality ◽  
Care Needs ◽  
Individual Level ◽  
Chronic Stressors ◽  
The World ◽  
Aging Adults ◽  
The Individual

AbstractThe care needs for aging adults are increasing burdens on health systems around the world. Efforts minimizing risk to improve quality of life and aging have proven moderately successful, but acute shocks and chronic stressors to an individual’s systemic physical and cognitive functions may accelerate their inevitable degradations. A framework for resilience to the challenges associated with aging is required to complement on-going risk reduction policies, programs and interventions. Studies measuring resilience among the elderly at the individual level have not produced a standard methodology. Moreover, resilience measurements need to incorporate external structural and system-level factors that determine the resources that adults can access while recovering from aging-related adversities. We use the National Academies of Science conceptualization of resilience for natural disasters to frame resilience for aging adults. This enables development of a generalized theory of resilience for different individual and structural contexts and populations, including a specific application to the COVID-19 pandemic.

scholarly journals Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Andreas Peters ◽  
Zoltán S. Spakovszky
Keyword(s):  
Polar Angle ◽  
Secondary Flows ◽  
Tip Vortex ◽  
System Level ◽  
Analysis Tool ◽  
Acoustic Analogy ◽  
Wake Interaction ◽  
Open Rotor ◽  
And Performance ◽  
The Individual

Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3D unsteady, full-wheel CRP computational fluid dynamics computations and aeroacoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance, and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full-wheel unsteady 3D Reynolds-averaged Navier-Stokes (RANS) simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method was extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows, and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was redesigned for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the redesigned CRP demonstrated an average reduction of 7.25 dB in mean sound pressure level computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the redesigned CRP demonstrated a reduction of 9.2 dB in effective perceived noise (EPNdB) and 8.6 EPNdB at the Federal Aviation Regulations (FAR) 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements.

Public Spending and Social Policy: The United Kingdom 1950–1977

1980 ◽  
Vol 9 (3) ◽  
pp. 337-357 ◽  
Author(s):  
Frank Gould ◽  
Barbara Roweth
Keyword(s):  
United Kingdom ◽  
Social Policy ◽  
Social Welfare ◽  
Public Expenditure ◽  
Public Spending ◽  
International Study ◽  
Theoretical Background ◽  
Welfare Spending ◽  
The United Kingdom ◽  
The Individual

ABSTRACTThis article, in which we examine developments in public expenditure on social policy in relation to total public spending in the United Kingdom (UK) in the period after the Second World War, is part of a larger international study on developments in social welfare spending on which we are currently engaged.In Section 1 we briefly sketch in the theoretical background to the study of public expenditure growth in general and social welfare spending in particular. We shall not in this article attempt to evaluate the validity of the competing hypotheses – this exercise is in hand as part of the international study, and we shall report the findings at a later date. Section 2 examines the growth of public expenditure in the UK at the aggregate level. In Section 3 we analyse public expenditure at the individual programme level and in Section 4 we summarize the conclusions.

Interventions Promoting Educators’ Use of Data: Research Insights and Gaps

2012 ◽  
Vol 114 (11) ◽  
pp. 1-48 ◽  
Author(s):  
Julie A. Marsh
Keyword(s):  
Data Collection ◽  
Research Question ◽  
Time Frame ◽  
System Level ◽  
Quality Of Data ◽  
Leverage Points ◽  
Knowledge To Action ◽  
Use Of Data ◽  
The Individual ◽  
Capacity Data

Background/Context In recent years, states, districts, schools, and external partners have recognized the need to proactively foster the use of data to guide educational decision-making and practice. Understanding that data alone will not guarantee use, individuals at all levels have invested in interventions to support better access to, interpretation of, and responses to data of all kinds. Despite the emergence of these efforts, there has been little systematic examination of research on such efforts. Purpose/Objective/Research Question/Focus of Study This article synthesizes what we currently know about interventions to support educators’ use of data—ranging from comprehensive, system-level initiatives, such as reforms sponsored by districts or intermediary organizations, to more narrowly focused interventions, such as a workshop. The article summarizes what is what is known across studies about the design and implementation of these interventions, their effects at the individual and organizational levels, and the conditions shown to affect implementation and outcomes. Research Design Literature review. Data Collection and Analysis This review entailed systematic searches of electronic databases and careful sorting to yield a total of 41 books, peer-reviewed journal articles, and reports. Summaries of each publication were coded to identify the study methods (design, framework, sample, time frame, data collection), intervention design (level of schooling, focal data and data user, leverage points, components), and findings on implementation, effects, and conditions. Findings/Results The review uncovers a host of common themes regarding implementation, including promising practices (e.g., making data “usable” and “safe,” targeting multiple leverage points) and persistent challenges (e.g., developing support that is generic but also customized, sustaining sufficient support). The review also finds mixed findings and levels of research evidence on effects of interventions, with relatively more evidence on effects on educators’ knowledge, skills, and practice than on effects on organizations and student achievement. The article also identifies a set of common conditions found to influence intervention implementation and effects, including intervention characteristics (capacity, data properties), broader context (leadership, organizational structure), and individual relationships and characteristics (trust, beliefs and knowledge). Conclusions/Recommendations The review finds that the current research base is limited in quantity and quality. It suggests the need for more methodologically rigorous research and greater attention to the organizational and student-level outcomes of interventions, comparative analyses, interventions that help educators move from knowledge to action, and specific ways in which the quality of data and leadership practices shape the effectiveness of interventions.

A Novel Embedded System Architecture for Fire Detection Based on Image Processing

2014 ◽  
Vol 608-609 ◽  
pp. 454-458
Author(s):  
Wei Bai ◽  
Chen Yuan Hu
Keyword(s):  
Image Processing ◽  
Embedded System ◽  
System Architecture ◽  
Cooperative Control ◽  
Processing System ◽  
Fire Detection ◽  
System Level ◽  
High Definition ◽  
The Embedded System ◽  
Pass Through

This paper presents novel logic/software co-work architecture for embedded high definition image processing platform, which is built by the considerations of system level, board hardware level, and the tasks partition between CPU processing and programmable logic based on the latest launched System on Chip Field Programmable Gate Array (Soc FPGA) – Xilinx ZC7020. For this case, we comprehensive analyze of the critical data paths: the uniform Advanced Extensible Interface (AXI) processing between processing system (PS) and processing logic (PL), including high definition video pass through PL to PS and PS software processing send to PL for speed up. We have included the transplant of opensource Linux, multiprocessing cooperative control and boot loader in PS side. Since the general platform is proposed, a fire detection approach based on high definition image processing is implemented. Experiment results indicated the feasibility and universality of the embedded system architecture.

Operationalising resilience in tropical agricultural value chains

2019 ◽  
Vol 24 (2) ◽  
pp. 271-300 ◽  
Author(s):  
Joshua Aboah ◽  
Mark M.J. Wilson ◽  
Karl M. Rich ◽  
Michael C. Lyne
Keyword(s):  
Value Chain ◽  
Food System ◽  
Raw Materials ◽  
Citation Network ◽  
System Level ◽  
Value Chains ◽  
Common Source ◽  
Content Type ◽  
The Individual ◽  
Stakeholder Interactions

Purpose The analysis of the concept of resilience in supply chain management studies mostly focuses on the downstream side of the value chain and tacitly assumes an unlimited supply of raw materials. This assumption is unreasonable for agricultural value chains, as upstream disruptions clearly have a material impact on the availability of raw materials, and indeed, are a common source of supply problems. This paper aims to present a framework for the operationalisation of the concept of socioecological resilience in agricultural value chains that incorporates upstream activities. Design/methodology/approach A citation network analysis was adopted to review articles. A conceptual framework is then advanced to identify elements of resilience and indicators relevant to tropical agricultural value chains. Findings There are limited studies that assess resilience in the food chain context. Flexibility, collaboration, adaptability and resourcefulness are key elements for assessing resilience at the individual chain actor level. However, the paper argues that adaptability is the relevant element for the assessment of resilience at an aggregate food system level because it considers the alteration of a system’s state of resilience. Practical implications The proposed framework and propositions accommodate stakeholder interactions in the value chain and could serve as a tool to guide the assessment of resilience in agricultural value chains. Originality/value This paper is one of the few to extend resilience to cover the socioecological interaction aspects for supply chains that yield the raw materials needed for continuity in channel-wide value creation processes.

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