Monitoring, Diagnostics, and Prognostics for Robot Tool Center Accuracy Degradation

2018 ◽  
Author(s):  
Guixiu Qiao ◽  
Brian A. Weiss
Keyword(s):  
Health Management ◽  
Control Strategies ◽  
Test Methods ◽  
Component Level ◽  
Data Set ◽  
Root Cause ◽  
Robot Systems ◽  
Robot Performance ◽  
And Control ◽  
Constituent Elements

Over time, robots degrade because of age and wear, leading to decreased reliability and increasing potential for faults and failures; this negatively impacts robot availability. Economic factors motivate facilities and factories to improve maintenance operations to monitor robot degradation and detect faults and failures, especially to eliminate unexpected shutdowns. Since robot systems are complex, with sub-systems and components, it is challenging to determine these constituent elements’ specific influence on the overall system performance. The development of monitoring, diagnostic, and prognostic technologies (collectively known as Prognostics and Health Management (PHM)), can aid manufacturers in maintaining the performance of robot systems by providing intelligence to enhance maintenance and control strategies. This paper presents the strategy of integrating top level and component level PHM to detect robot performance degradation (including robot tool center accuracy degradation), supported by the development of a four-layer sensing and analysis structure. The top level PHM can quickly detect robot tool center accuracy degradation through advanced sensing and test methods developed at the National Institute of Standards and Technology (NIST). The component level PHM supports deep data analysis for root cause diagnostics and prognostics. A reference data set is collected and analyzed using the integration of top level PHM and component level PHM to understand the influence of temperature, speed, and payload on robot’s accuracy degradation.

Hierarchical Decomposition of a Manufacturing Work Cell to Promote Monitoring, Diagnostics, and Prognostics

2017 ◽  
Author(s):  
Brian A. Weiss ◽  
Guixiu Qiao
Keyword(s):  
Machine Tools ◽  
Health Management ◽  
Control Strategies ◽  
Industrial Robot ◽  
Work Cell ◽  
Critical Elements ◽  
Functional Relationships ◽  
Manufacturing Operations ◽  
Robot Systems ◽  
And Control

Manufacturing work cell operations are typically complex, especially when considering machine tools or industrial robot systems. The execution of these manufacturing operations require the integration of layers of hardware and software. The integration of monitoring, diagnostic, and prognostic technologies (collectively known as prognostics and health management (PHM)) can aid manufacturers in maintaining the performance of machine tools and robot systems by providing intelligence to enhance maintenance and control strategies. PHM can improve asset availability, product quality, and overall productivity. It is unlikely that a manufacturer has the capability to implement PHM in every element of their system. This limitation makes it imperative that the manufacturer understand the complexity of their system. For example, a typical robot systems include a robot, end-effector(s), and any equipment, devices, or sensors required for the robot to perform its task. Each of these elements is bound, both physically and functionally, to one another and thereby holds a measure of influence. This paper focuses on research to decompose a work cell into a hierarchical structure to understand the physical and functional relationships among the system’s critical elements. These relationships will be leveraged to identify areas of risk, which would drive a manufacturer to implement PHM within specific areas.

Modeling of a Partial-Flow, Diesel, Lean NOx Trap Systems

2005 ◽  
Author(s):  
Shawn Midlam-Mohler ◽  
Yann Guezennec
Keyword(s):  
Diesel Fuel ◽  
Control Strategies ◽  
Nox Reduction ◽  
Lean Nox Trap ◽  
Component Level ◽  
Lean Nox ◽  
Catalyst Temperature ◽  
The Rich ◽  
And Control ◽  
Regeneration Systems

Lean NOx Traps (LNTs) have shown promise for Diesel applications; however, production implementation in vehicles poses a number of challenges. Much of the literature reports on LNT systems in which the catalyst always receives the full flow of exhaust from the engine, referred here as full-flow regeneration systems. Another implementation of the LNT is one in which the exhaust can be partially or fully diverted from the catalyst to allow local introduction of the necessary reductants for regeneration. The physical aspects of one such system, as well as a control-oriented model are presented with experimental validation. In the system described here, the exhaust flow is diverted around the catalyst during regenerations. In the low exhaust flow through the catalyst, reductant is added (Diesel fuel typically) which provides the rich conditions for regenerating the trap. This allows the engine to continue to run in normal lean mode, which overcomes one of the major challenges for full-flow regeneration systems. Successful regeneration with liquid Diesel fuel is strongly dependent on catalyst temperature, which is addressed by proper thermal management of the system through the addition of fuel prior to regeneration. In this paper, both component level and vehicle level simulations are presented in terms of fuel economy versus NOx reduction. Several different system configurations and control strategies are compared.

scholarly journals Bacteria-Bacteriophage Cycles Facilitate Cholera Outbreak Cycles: An Indirect Susceptible - Infected - Bacteria - Phage (Isibp) Model-Based Mathematical Study

2021 ◽  
Author(s):  
Asma Al Habees ◽  
Eman Aldabbas ◽  
Nicola Bragazzi ◽  
Jude Kong
Keyword(s):  
Bacterial Population ◽  
Compartmental Model ◽  
Health Management ◽  
Control Strategies ◽  
Equilibrium Points ◽  
Infectious Agent ◽  
Sensitivity Analyses ◽  
And Control ◽  
Disease Free ◽  
Phage Population

Cholera is an acute enteric infectious disease caused by the Gram-negative bacterium Vibrio Cholerae. Despite a huge body of research, the precise nature of its transmission dynamics has yet to be fully elucidated. Mathematical models can be useful to better understand how an infectious agent can spread and be properly controlled. We develop a compartmental model describing a Human population, a bacterial population as well as a phage population. We show that there might be eight equilibrium points; one of which is a disease free equilibrium point. We carry out numerical simulations and sensitivity analyses and we show that the presence of phage can reduce the number of infectious individuals. Moreover, we discuss the main implications in terms of public health management and control strategies.

scholarly journals Inter-provincial disparity of COVID-19 transmission and control in Nepal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Buddhi Pantha ◽  
Subas Acharya ◽  
Hem Raj Joshi ◽  
Naveen K. Vaidya
Keyword(s):  
Growth Rate ◽  
Disease Transmission ◽  
Reproduction Number ◽  
Control Strategies ◽  
National Level ◽  
Effective Control ◽  
Data Set ◽  
Control Policies ◽  
Local Spread ◽  
And Control

AbstractDespite the global efforts to mitigate the ongoing COVID-19 pandemic, the disease transmission and the effective controls still remain uncertain as the outcome of the epidemic varies from place to place. In this regard, the province-wise data from Nepal provides a unique opportunity to study the effective control strategies. This is because (a) some provinces of Nepal share an open-border with India, resulting in a significantly high inflow of COVID-19 cases from India; (b) despite the inflow of a considerable number of cases, the local spread was quite controlled until mid-June of 2020, presumably due to control policies implemented; and (c) the relaxation of policies caused a rapid surge of the COVID-19 cases, providing a multi-phasic trend of disease dynamics. In this study, we used this unique data set to explore the inter-provincial disparities of the important indicators, such as epidemic trend, epidemic growth rate, and reproduction numbers. Furthermore, we extended our analysis to identify prevention and control policies that are effective in altering these indicators. Our analysis identified a noticeable inter-province variation in the epidemic trend (3 per day to 104 per day linear increase during third surge period), the median daily growth rate (1 to 4% per day exponential growth), the basic reproduction number (0.71 to 1.21), and the effective reproduction number (maximum values ranging from 1.20 to 2.86). Importantly, results from our modeling show that the type and number of control strategies that are effective in altering the indicators vary among provinces, underscoring the need for province-focused strategies along with the national-level strategy in order to ensure the control of a local spread.

scholarly journals Correlations between mechanical and geometrical parameters in aggregates: a tool for quality assessment and control

2013 ◽  
Vol 47 (4) ◽  
pp. 2069 ◽  
Author(s):  
D. Xirouchakis
Keyword(s):  
Abrasion Resistance ◽  
Shape Index ◽  
Test Methods ◽  
Standard Test ◽  
Geometrical Parameters ◽  
Strongly Correlated ◽  
Data Set ◽  
Resistance To Wear ◽  
And Performance ◽  
And Control

Correlations between mechanical and geometrical parameters in aggregates can be used as quality and performance prediction tools. I evaluated the following parameter pairs: dry and wet resistance to wear (MDE & MDS), and resistance to fragmentation (LA); polishing resistance and abrasion (PSV–AAV); and flakiness and shape index (FI–SI). The data set comprises slags, sedimentary, igneous, and metamorphic rocks tested according to EN standard test methods. FI and SI are positively correlated (r = 0.83) and can be well described by the 1:1 line. Wet and dry resistance to wear are strongly correlated (r = 0.98) with MDE ≈ 2·MDS. Dry resistance to fragmentation (LA) and wet resistance to wear (MDE) are well correlated (r = 0.81), and can be described with the equation LA = 4.95×MDE 0,61 (R2 = 0.69). According to the PSV–AAV correlation, aggregates are divided into two groups with contrasting behavior. Limestones and slags (r = −0.49 to −0.69) exhibit high polishing for high abrasion resistance (high PSV–low AAV), whereas sandstones and mafic to intermediate volcanics (r = 0.44 to 0.39) exhibit high polishing for low abrasion resistance (high PSV–high AAV). Peridotites belong to either PSV–AAV group depending on the soft minerals.

scholarly journals Online User Information Sharing and Government Pandemic Prevention and Control Strategies-Based on Evolutionary Game Model

2021 ◽  
Vol 9 ◽  
Author(s):  
Yao Xiao ◽  
Wanting Xu ◽  
Shouzhen Zeng ◽  
Qiao Peng
Keyword(s):  
Prevention And Control ◽  
Personal Information ◽  
Control Strategies ◽  
Evolutionary Game ◽  
Root Cause ◽  
Behavioral Expectations ◽  
Internet Users ◽  
Control And Prevention ◽  
Privacy Risks ◽  
And Control

Background: The sharing and utilization of online users' information has become an important resource for governments to manage COVID-19; however, it also involves the risk of leakage of users' personal information. Online users' sharing decisions regarding personal information and the government's COVID-19 prevention and control decisions influence each other and jointly determine the efficiency of COVID-19 control and prevention.Method: Using the evolutionary game models, this paper examines the behavioral patterns of online users and governments with regard to the sharing and disclosure of COVID-19 information for its prevention and control.Results: This paper deduce the reasons and solutions underlying the contradiction between the privacy risks faced by online users in sharing information and COVID-19 prevention and control efforts. The inconsistency between individual and collective rationality is the root cause of the inefficiency of COVID-19 prevention and control.Conclusions: The reconciliation of privacy protection with COVID-19 prevention and control efficiency can be achieved by providing guidance and incentives to modulate internet users' behavioral expectations.

Effective infection prevention and control strategies in a large accredited psychiatric facility in Singapore

2020 ◽  
Author(s):  
Daniel Poremski ◽  
Sandra Henrietta Subner ◽  
Grace Lam Fong Kin ◽  
Raveen Dev Ram Dev ◽  
Mok Yee Ming ◽  
...  
Keyword(s):  
Mental Health ◽  
Prevention And Control ◽  
Infection Prevention ◽  
Control Strategies ◽  
Infection Prevention And Control ◽  
Psychiatric Facility ◽  
Essential Services ◽  
Community Transmission ◽  
And Control

The Institute of Mental Health in Singapore continues to attempt to prevent the introduction of COVID-19, despite community transmission. Essential services are maintained and quarantine measures are currently unnecessary. To help similar organizations, strategies are listed along three themes: sustaining essential services, preventing infection, and managing human and consumable resources.

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