PLC在振打电机控制中的应用

本文给出了用可编程序控制器实现振打电机控制的设计过程，外部接线和程序框图。在同一台电除尘器中，将第一电场的振打时序作为其它电场时序控制的基准，从而避免了采用独立控制时因定时器长期累积误差所造成各电场之间振打时序关系的错误。经实际应用表明：该控制方案简单、可靠，能取得较好的实际效果。     

基于PIC16F72单片机无刷直流电机控制器设计

随着人们生活水平的提高和现代化生产、办公自动化的发展,家用电器、工业机器人等设备都越来越趋向于高效率化、小型化及高智能化,作为执行元件的重要组成部分,电机必须具有精度高、速度快、效率高等特点,无刷直流电机的应用也因此而迅速增长,本设计是通用无刷电机的控制器设计,以PIC16F72单片机为控制电路,单片机采集比较电平及电机霍尔反馈信号,通过软件编程控制无刷直流电动机,实验表明具有较好的参考价值。     

动作技能系统复杂性特征及耗散结构理论视角下研究路径探析

采用文献资料、逻辑分析等研究方法,根据科学家PaulColliers的关于复杂性系统的较具代表性的理论,结合动作技能特征,对动作技能系统的复杂性表现进行归纳。以耗散结构理论为方法论指导,分别从耗散结构形成的条件即系统的开放性、远离平衡态、非线性相互作用和涨落机制四个方面对动作技能系统进行研究,从而为实践工作中动作技能学习与控制策略的选取提供理论依据和方法指导。     

Diagnosis and Monitoring of Basic Motor Competencies among Third-Graders in Luxembourg. An Assessment Tool for Teachers

ABSTRACT

Basic motor competencies (in German: Motorische Basiskompetenzen; MOBAK) are performance dispositions empowering children to participate in the movement culture. For the diagnosis of basic motor competencies, a test instrument consisting of 15 test items for assessing third graders’ basic motor competencies was developed (MOBAK-LUX-3) and validated empirically. Basic motor competencies were operationalized as test items in the form of basic motor qualifications, which are cultural tools formulated as a minimum standard. Data (MOBAK-LUX-3, age, gender, migration background, weight, height, sport club membership, weekly physical activity) were collected in 2015 amongst third-graders in elementary school in Luxembourg (N = 488; 50.4% female; M age = 8.8 years, SD = .51). A confirmatory factor analysis confirmed a four-factor structure (locomotion, object control, moving in water, object locomotion; CFI = .94; TLI = .92; RMSEA = .036; WRMR = 0.89). Five classes with different competence profiles were determined through latent class analysis. The MOBAK-LUX-3 test instrument satisfies test theory requirements and can be used to determinate motor competence profiles.     

Only tomorrow: Delayed effects of teachers attitude on motor skill learning

Motor skill tasks provide unique opportunities to examine the impact of teachers' feedback on learners’ performance, as the quality and quantity of motor behavior can be objectively assessed during the practice session (online-gains) and afterwards (delayed, offline-gains). We tested the learning and overnight retention of a newly instructed movement sequence in young healthy adults in three conditions of teacher-learner interaction, determined by the feedback afforded by the teacher: Indifferent-minimal (IM), General-encouragement (GE), Positive-social-comparison (PSC). All three conditions resulted in robust within-session gains in speed with no loss of accuracy. However, overnight, most trainees in the GE and PSC groups, but not in the IM group, expressed additional delayed gains. PSC group also exhibited feedback-induced increase in positive mood, which was correlated with their delayed gains. These results indicate that teacher-learner interactions during the learning session can affect long-term skill by modulating memory consolidation processes, even when within-session gains are unaffected.     

练习变异性在运动技能学习中的研究进展

练习变异性与一般动作程序的参数变化有关,是通过改变运动参数及不同的背景干扰效应对练习效果产生影响,相对比于以往的固定练习法,变换练习法能够使参与者在练习运动技能过程中因环境、速度、距离、力量等参数的不同,从而体验到不同的运动特征,有效地促进运动技能的学习。现就近10年的研究成果进行综述,希望为今后的研究带来裨益。     

Motor performance and bodyweight of children and adolescents in Saarland – Status quo

Abstract

The motor performance of children and adolescents has been a subject of controversial discussion. As part of a pilot project, 839 schoolchildren from 14 different schools in Saarland were studied and their height, weight and sport motor performance were measured using the German motor performance test DMT 6-18. The results show a slight increase in the number of overweight children compared to reference samples. However, these discrepancies are minor and cannot be judged to be practically relevant because of the weakness of the effects. The average motor test performances of the Saarland schoolchildren were above the average performance of the reference samples in almost all individual performances. There are also hardly any weaker performances in comparison to older studies. The current results for motor performance of Saarland children and adolescents do not, therefore, give any great reason for concern. Further evaluation steps will be needed to clarify the influences that might be associated with adverse characteristics for motor performance (socio-economic status, living situation, leisure behaviour, school performance, etc.).     

Measurement error in short-term power testing in young people

The aim of this study was to examine the consistency or reproducibility of measuring cycling peak power in children and adults. Twenty-seven pre-pubertal girls and boys and 27 female and male physical education students (age 9.8±0.5 and 24.4±4.3 years, respectively; mean±s) participated in the study. All participants performed five tests over 15 days and underwent a habituation session before the study. Each test included four sprints against four different braking forces. We found that braking forces of 7.5% of body weight in children and 10% of body weight in adults were too high for most of the participants to elicit maximal cycling power. Unlike the children, the physical education students improved their performance between session 1 and session 2 (1025±219 vs 1069±243 W; P<0.001). Therefore, to obtain reproducible measures of cycling peak power, a habituation session including a complete test protocol (i.e. warm-up plus three sprints) is highly recommended. When the protocol included three sprints in children and at least two sprints in adults, measurement of cycling peak power was found to be highly reliable (test-retest coefficient of variation ～3%). Finally, to avoid performance fluctuations, especially over several consecutive evaluations (e.g. longitudinal studies), it is necessary to maintain high motivation in children.     

Analogy learning: A means to implicit motor learning

Two experiments were conducted to examine the hypothesis that learning by analogy will invoke characteristics of an implicit mode of motor learning. In the first experiment, table tennis novices learned to hit forehand topspin implicitly, explicitly or by analogy. The results showed that the analogy and implicit learning groups accumulated equivalently fewer explicit rules than the explicit learning group during the learning phase. When a concurrent secondary task was added, the explicit learning group suffered from a significantly more serious performance impairment than the analogy and implicit learning groups; no significant differences were seen between the latter two groups. Self-perceived performance was correlated to actual performance in the explicit learning group but not in the analogy or the implicit learning groups. In the second experiment, the performance of an explicit learning group was found to be impaired by both a stress intervention and a thought suppression intervention, whereas the performance of an analogy learning group was not. These characteristics of analogy learning parallel those reported in the implicit learning literature, suggesting that analogy learning may be an effective method for teaching skills implicitly in sport.     

基于机器视觉技术的音圈电机磁钢自动检测系统

为实现音圈电机磁钢轮廓的快速检测,提出了一个由图像采集、系统照明、图像处理和单片机控制下的分拣模块等几个部分构成的自动检测系统,简要介绍了系统硬件模块的设计方法,并根据实际VCM磁钢的轮廓特征提出了软件设计的具体算法．最后给出了音圈电机磁钢轮廓检测的实验结果,表明此系统设计方案简易可行．