Design and Performance Study of a 3-DOF Micropositioning Table

2006 ◽  
Vol 315-316 ◽  
pp. 450-454
Author(s):  
Yan Ling Tian ◽  
Da Wei Zhang ◽  
Cheng Zu Ren ◽  
Bing Yan

In order to implement dynamic compensation for the wheel vibration of surface grinding machine, a micropositioning table with high stiffness and response frequency is designed. The micropositioning table is driven by three piezoelectric actuators with stiffness of 400 N/μm. Three capacitive sensors are utilized to form feedback control and flexure hinges are used to guide the moving part and preload for the piezoelectric actuators. The kinetics of the micropositioning table has been analyzed to understand the relationship of the control voltage and the posture of the moving part. Due to the coupling characteristic of the system, the decoupling control method is introduced to improve the performance of the table. Experimental tests are carried out to investigate the performance of the micropositioning table.

2010 ◽  
Vol 136 ◽  
pp. 153-157
Author(s):  
Yu Hong Du ◽  
Xiu Ming Jiang ◽  
Xiu Ren Li

To solve the problem of detecting the permeability of the textile machinery, a dedicated test system has been developed based on the pressure difference measuring method. The established system has a number of advantages including simple, fast and accurate. The mathematical model of influencing factors for permeability is derived based on fluid theory, and the relationship of these parameters is achieved. Further investigations are directed towards the inherent characteristics of the control system. Based on the established model and measuring features, an information fusion based clustering control system is proposed to implement the measurement. Using this mechanical structure, a PID control system and a cluster control system have been developed. Simulation and experimental tests are carried out to examine the performance of the established system. It is noted that the clustering method has a high dynamic performance and control accuracy. This cluster fusion control method has been successfully utilized in powder metallurgy collar permeability testing.


2019 ◽  
Vol 13 (4) ◽  
Author(s):  
Zahra Khashei Varnamkhasti ◽  
Bardia Konh

Abstract Many medical treatments such as brachytherapy, thermal ablation, and biopsy are performed using percutaneous needle-based procedures. The success of these procedures highly depends on accurate placement of the needle tip at target positions. A novel active needle was designed and developed in this work that can steer inside the tissue via a shape memory alloy (SMA) actuator attached to its body. With actuation and control offered by the actuator, the active needle can reach the target positions with more accuracy, and thereby potential improvement in clinical outcomes. An integrated system was also developed to robotically operate the active needle insertion. The performance of the active needle was evaluated with finite element methods and experimental tests on a fabricated prototype in air. Active needle insertion tests in a tissue phantom were also performed to evaluate the performance of the active needle. The deflection in air and tissue phantom demonstrated the capability of the active needle to reach target positions.


1986 ◽  
Vol 50 (5) ◽  
pp. 264-267 ◽  
Author(s):  
GH Westerman ◽  
TG Grandy ◽  
JV Lupo ◽  
RE Mitchell

2016 ◽  
Vol 6 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Kathleen Van Benthem ◽  
Chris M. Herdman

Abstract. Identifying pilot attributes associated with risk is important, especially in general aviation where pilot error is implicated in most accidents. This research examined the relationship of pilot age, expertise, and cognitive functioning to deviations from an ideal circuit trajectory. In all, 54 pilots, of varying age, flew a Cessna 172 simulator. Cognitive measures were obtained using the CogScreen-AE ( Kay, 1995 ). Older age and lower levels of expertise and cognitive functioning were associated with significantly greater flight path deviations. The relationship between age and performance was fully mediated by a cluster of cognitive factors: speed and working memory, visual attention, and cognitive flexibility. These findings add to the literature showing that age-related changes in cognition may impact pilot performance.


2014 ◽  
Vol 45 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Robert J. Calin-Jageman ◽  
Tracy L. Caldwell

A recent series of experiments suggests that fostering superstitions can substantially improve performance on a variety of motor and cognitive tasks ( Damisch, Stoberock, & Mussweiler, 2010 ). We conducted two high-powered and precise replications of one of these experiments, examining if telling participants they had a lucky golf ball could improve their performance on a 10-shot golf task relative to controls. We found that the effect of superstition on performance is elusive: Participants told they had a lucky ball performed almost identically to controls. Our failure to replicate the target study was not due to lack of impact, lack of statistical power, differences in task difficulty, nor differences in participant belief in luck. A meta-analysis indicates significant heterogeneity in the effect of superstition on performance. This could be due to an unknown moderator, but no effect was observed among the studies with the strongest research designs (e.g., high power, a priori sampling plan).


Author(s):  
Jyoti Baijal

Examination stress is a ubiquitous phenomenon that has, in the present times, adversely affected the learning outcomes and performance of the students at all levels- primary, secondary or higher education. It’s increasing intensity specifically among students appearing for high stakes board examination evokes a response from the teaching fraternity at the earliest. The reason being that a prolonged experience of stress with respect to evaluative situations is bound to prove detrimental to the mental, physical and emotional well-being of the students. For the nation to develop and progress towards a knowledge society, it is imperative that the students are taught to cope with stressful stimuli and improve performance. Study-Skills Training is an intervention intended to improve their study and test- taking habits and skills. It is based on a cognitive-deficit model which is directed towards improving a variety of cognitive activities that affect the organization, processing and retrieval of information and thereby help in reducing the experience of examination stress. Systematic desensitization as a process can be used to unlearn anxiety reactions by replacing the anxiety response with a calm, relaxed state. Thus, a combination of study-skills training and systematic desensitization has been shown to be effective and superior in alleviating test anxiety


2018 ◽  
Vol 20 (1) ◽  
pp. 89 ◽  
Author(s):  
Andi Ina Yustina ◽  
Tifanny Valerina

This paper examines whether the work-family conflict (related to both work-interfering-family and family-interfering-work) of auditors affects their performance and if so, whether the effect is mediated by emotional exhaustion and job satisfaction. A mail survey is used to deliver a questionnaire to 151 auditors from ten CPA firm in Indonesia. The result shows that emotional exhaustion and job satisfaction fully mediates the relationship of work-family conflict with job performance. The result also demonstrates that Work-Interfering-Family (WIF) has significant effects on emotional exhaustion and job satisfaction, but Family-Interfering-Work (FIW) has no significant influence on either emotional exhaustion or job satisfaction. This study suggests that maintaining a regular training program for auditors, having flexible working arrangements, and encouraging a healthy lifestyle may help to reduce the work-family conflict and will increase the job satisfaction and performance of auditors.


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