A New Method for Sensor Degradation Detection, Isolation and Compensation in Linear Systems

2007 ◽  
Author(s):  
Li Jiang ◽  
Dragan Djurdjanovic ◽  
Jun Ni
Keyword(s):  
Degradation Process ◽  
Accurate Information ◽  
Electronic Throttle ◽  
Performance Diagnosis ◽  
Automotive Electronic ◽  
Engineering Designs ◽  
State Space System ◽  
Measurement Devices ◽  
Sensor Degradation ◽  
And Control

The performance of machines and equipment degrades as a result of aging and wear. This decreases performance reliability and increases the potential for faults and failures. To ensure proper functionality of complex systems, advanced technologies for performance diagnosis and control are being incorporated into engineering designs, which requires an ever-increasing number of sensors and measurement devices. Nevertheless, a sensor, just as any other dynamic system, degrades and fails. A faulty sensor may cause process performance degradation, process shut down, or even a fatal accident because it is no longer able to deliver accurate information about the monitored system. Therefore, it is essential to assess sensor performance to ensure system reliability. In this paper, a method is proposed to detect, isolate, and compensate sensor degradation. The numerical algorithm for subspace state space system identification is used to track the changes of the time constants and gains of the sensor and the monitored system. Without imposing requirements for redundant sensors and measurement devices, this method utilizes the fact that sensor readings depict dynamic characteristics of the sensors as well as those of the monitored system. The newly proposed method is verified in angular sensor degradation detection using high-fidelity simulations of an automotive electronic throttle system.

Decision Support Systems in Indian Organized Retail Sector

2010 ◽  
pp. 1043-1055 ◽  
Author(s):  
Ankush Sharma ◽  
Preeta Vyas
Keyword(s):  
Decision Making ◽  
Decision Support ◽  
Competitive Advantage ◽  
Decision Support Systems ◽  
Support Systems ◽  
Regulatory Environment ◽  
Accurate Information ◽  
Retail Sector ◽  
Technological Developments ◽  
And Control

Retailing is in a rapid state of change due to speedy technological developments, changing competitive positions, varying consumer behaviour as well as their expectations and liberalized regulatory environment. In such a scenario, information is crucial to plan and control profitable retail businesses and it can be an important source of competitive advantage so long as it is affordable and readily available. DSS (Decision Support Systems) which provide timely and accurate information can be viewed as an integrated entity providing management with the tools and information to assist their decision making.

Fracture mechanics in design and service: ‘living with defects’ - Statistical aspects of design: risk assessment and structural integrity

1981 ◽  
Vol 299 (1446) ◽  
pp. 111-130 ◽  
Keyword(s):  
Fracture Mechanics ◽  
Structural Reliability ◽  
Structural Integrity ◽  
Product Liability ◽  
Probabilistic Methods ◽  
Statistical Variations ◽  
Engineering Designs ◽  
Recent Developments ◽  
Quantitative Basis ◽  
And Control

Statistical variations in input parameters that affect structural reliability have historically been incorporated approximately in engineering designs by application of safety factors. Increased concerns over the injury potential and costs of licensing, insurance, field repairs or recalls, and product liability claims now demand more quantitative evaluation of possible flaws or unusual usage conditions that might result from statistical variations or uncertainties. This paper describes the basic concepts of probabilistic fracture mechanics that are used to assess and control risk. Recent developments in combined analysis methods are presented that utilize field experience data with probabilistic analysis to improve the accuracy of the structural integrity predictions. Several specific examples are described that illustrate how these probabilistic methods are used to assess risk and to provide a quantitative basis for establishing design, operation or maintenance allowables. These procedures, which realistically model the actual statistical variations that exist, can eliminate unnecessarily conservative approximations and often achieve improved reliability at reduced cost.

Estimation of Friction and States for Robust Control of Position Servo

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Shailaja Kurode ◽  
Bhagyashri Tamhane
Keyword(s):  
Robust Control ◽  
System Performance ◽  
Accurate Information ◽  
Position Tracking ◽  
Performance Tracking ◽  
Friction Component ◽  
Accurate Position ◽  
System States ◽  
State Estimations ◽  
And Control

Abstract Friction is an inherent nonlinearity in electromechanical systems. It adversely affects the system performance. The key challenge is to get its accurate information as it is not measurable. This paper proposes a two-observer concept for friction and state estimation. Novelty of proposal includes finite time convergent estimations of the friction component and the system states. These estimations are used to design a robust control for accurate position tracking in servosystem. It is shown that accurate friction and state estimations are obtained, and control efforts are reduced while achieving precise performance. Tracking performance is improved using proposed control. The outcome of the proposed methodology is validated through computer simulations and experimentations.

scholarly journals Total and Free Deoxypyridinoline after Acute Osteoclast Activity Inhibition

1999 ◽  
Vol 45 (9) ◽  
pp. 1510-1516 ◽  
Author(s):  
Alessandro Rubinacci ◽  
Raffaella Melzi ◽  
Maria Zampino ◽  
Armando Soldarini ◽  
Isabella Villa
Keyword(s):  
Type I Collagen ◽  
Degradation Process ◽  
Type I ◽  
Short Term ◽  
Oral Calcium ◽  
Osteoclast Activity ◽  
High Bone ◽  
Highly Correlated ◽  
Acute Changes ◽  
And Control

Abstract Background: Deoxypyridinoline (Dpd) is one of the two pyridinium cross-links that provide structural rigidity to type I collagen in bone. During osteoclastic resorption, Dpd is released into circulation and is excreted in the urine in free and peptide-bound forms. Free and total Dpd are highly correlated, but whether the free-to-total cross-link ratio is constant in both normal and high bone turnover states remains controversial. To compare free and total Dpd performance in a physiological condition, urinary free and total Dpd were measured after a short-term inhibition of osteoclast activity such as that induced by an oral calcium load. Methods: Total and free Dpd were measured by HPLC and by immunosorbent assay, respectively, in two groups of subjects, one (calcium-treated; n = 16) taking calcium and the other not (control; n = 9). Results: The urinary excretion of total Dpd at 2 and 4 h after oral calcium loading was decreased compared with controls. By contrast, changes in free Dpd were similar in the calcium-treated and control groups, reflecting only circadian rhythm. Conclusions: Total and free Dpd do not show comparable sensitivity in detecting short-term inhibition of osteoclast activity. The degradation process of peptide-bound to free Dpd could render free Dpd insensitive to acute changes of osteoclast activity.

Degradation Behaviors of Biodegradable Aliphatic Polyesters and Polycarbonates

2020 ◽  
Vol 14 (2) ◽  
pp. 155-168 ◽  
Author(s):  
Yonghang Xu ◽  
Fangya Zhou ◽  
Danmin Zhou ◽  
Jintang Mo ◽  
Huawen Hu ◽  
...  
Keyword(s):  
Biodegradable Polymers ◽  
Degradation Mechanism ◽  
Polymeric Materials ◽  
Degradation Process ◽  
Biodegradable Plastics ◽  
Research Progress ◽  
Aliphatic Polyesters ◽  
Depth Study ◽  
Degradation Behaviors ◽  
And Control

Aliphatic polyesters and polycarbonates such as polylactide (PLA), polycaprolactone (PCL) and poly(propylene carbonate) (PPC), are well known as biodegradable, biocompatible and environmental-friendly polymeric materials, which have been widely used in various areas ranging from packaging to biomedical materials. The production and usage of biodegradable plastics can greatly alleviate the safety and environmental concerns because of the fairly short degradation periods and low toxicity of catabolite. During the degradation process of polymers, obvious changes appear in polymer structures and the physiochemical properties. Therefore, it is necessary to regulate and control the degradation behaviors and periods of biodegradable plastics such as polyesters and polycarbonates, which is significant for their more widespread popularization and applications. In this context, it is highly desirable to make a review contribution in this field so as to better understand the recent research progress on polymer degradation behaviors and kinetics, as well as the future prospect of biodegradable polymers. Herein, this paper reviews the research progress on the degradation behaviors of biodegradable polyesters and polycarbonates materials including PLA, PCL and PPC. Through an in-depth study of various internal/external factors, the degradation mechanism of these polymers is unraveled, which will motivate future studies into the synthesis of novel biodegradable polymers and the understanding of their degradation behavior on the molecular level.

scholarly journals Asymmetric modelling and control of an electronic throttle

2015 ◽  
Vol 29 (2) ◽  
pp. 192-204 ◽  
Author(s):  
Gisela Pujol ◽  
Yolanda Vidal ◽  
Leonardo Acho ◽  
Alessandro N. Vargas
Keyword(s):  
Electronic Throttle ◽  
And Control
Sign in / Sign up

Export Citation Format

Share Document