探究如何做好电机控制及保护工作

机电一体化通俗上来讲即将电子技术应用于传播控制、信息生成与流通,能源组织等,从构成上来说即是将电子技术和机械相融合,让二者的优势共同促进共同发展,变成统一体。科技水平进一步提高以来,机电一体化作为一门新型的学科,其将各种自动控制技术、电力电子技术以及接口技术和机械技术等群体技术集于一体,使得系统工程技术高质、低耗、多用及可靠的特定价值得以实现。本文就针对机电一体化系统中电机的控制与保护展开讨论。     

Integration of physically disabled students

Abstract

The article reviews research in four areas: impact of integration on children's self‐concept, attitudes toward physically disabled children, effects on their school achievement and teacher reactions to integration. Research evidence suggests that being together with non‐disabled peers makes the disabled child more aware of his physical impairment and restraints. But there are also signs indicating that psychological factors essential for a positive self‐evaluation are activated to a higher degree in the integrated environment. With respect to attitudes of peers there are some, although not conclusive, results suggesting positive influence of integration. Research on school achievement demonstrates the great variability among the physically disabled pupils, in comparison with which the impact of school placement is relatively minor. Teacher opinions about integration of physically disabled pupils are mainly positive, but if the handicap is severe integration is considered possible only with a rich supply of teaching material, reduced class size and support from specialists. The review concludes with glimpses from reports on practical experience with integration.     

基于Matlab的无刷直流电机的建模与仿真

分析了无刷直流电机的工作原理及控制系统的组成,推导出无刷直流电机的数学模型,利用此数学模型并借助Mablab仿真软件,建立了无刷直流电机的仿真模型,通过仿真实验,证明了该仿真模型的正确性及合理性。     

油田远程智能电机群控系统的研究

抽油机是石油开采中必须使用的设备,而电动机又是抽油机不可或缺的重要部分。根据电机在油田生产中的使用情况,采用无线电机群控系统方案,用于监测、保护和控制电机。本文对智能电机监控器的基本功能如电机参数的采集、电机保护、输出控制、数据传输等电路的设计原理和控制软件设计方法作了详细的阐述和认真的研究。     

Impaired motor control after sport-related concussion could increase risk for musculoskeletal injury: Implications for clinical management and rehabilitation

This review presents a conceptual framework and supporting evidence that links impaired motor control after sport-related concussion(SRC)to increased risk for musculoskeletal injury.Multiple studies have found that athletes who are post-SRC have higher risk for musculoskeletal injury compared to their counterparts.A small body of research suggests that impairments in motor control are associated with musculoskeletal injury risk.Motor control involves the perception and processing of sensory information and subsequent coordination of motor output within the central nervous system to perform a motor task.Motor control is inclusive of motor planning and motor learning.If sensory information is not accurately perceived or there is interference with sensory information processing and cognition,motor function will be altered,and an athlete may become vulnerable to injury during sport participation.Athletes with SRC show neuroanatomic and neurophysiological changes relevant to motor control even after meeting return to sport criteria,including a normal neurological examination,resolution of symptoms,and return to baseline function on traditional concussion testing.In conjunction,altered motor function is demonstrated after SRC in muscle activation and force production,movement patterns,balance/postural stability,and motor task performance,especially performance of a motor task paired with a cognitive task(i.e.,dual-task condition).The clinical implications of this conceptual framework include a need to intentionally address motor control impairments after SRC to mitigate musculoskeletal injury risk and to monitor motor control as the athlete progresses through the return to sport continuum.     

The hip control test is a valid and reliable measure of hip neuromuscular control

Abstract

Insufficient hip neuromuscular control may contribute to non-contact sport injuries. However, the current evaluative test of hip neuromuscular control, the single-leg squat, requires hip abductor muscle strength to complete. The purpose of this study was to develop the hip control test (HCT) and determine the test’s reliability and construct validity. Nineteen healthy adults visited the laboratory twice. The HCT is a 10-s test of reciprocal toe-tapping accuracy. Both automated and manual HCT ratings were recorded simultaneously during each visit. Additionally, eccentric hip abductor torque was measured. HCT reliability was assessed with intra-class correlation coefficients (ICC). Agreement between automated and manual ratings was determined with Bland–Altman plots. Construct validity was established if HCT performance significantly decreased with a secondary cognitive task (p < 0.05). Bivariate regression determined the relationship between HCT performance and eccentric hip abductor torque. Automated and manual HCT ratings both had moderate reliability (ICC = 0.72) and yielded similar results (limits of agreement = ?1 to 2 taps). The HCT had construct validity (p = 0.001), and no correlation with hip abductor muscle strength (r = 0.213). Thus, the HCT is a reliable and valid test. The HCT is simple to administer and measures hip neuromuscular control separately from strength.     

Gross motor coordination in junior tennis players

The purpose of this study was twofold: (1) to determine the gross motor coordination performance levels of junior tennis players and (2) to analyse the effects of age and gender. Participants were junior male (n = 50) and female (n = 51) tennis players aged 6–14. Körperkoordinationstest für Kinder (KTK) was used to assess the gross motor coordination of the participants. Results revealed that none of the participants performed lower than normal level in motor coordination. Besides, 40.6% of the participants performed above normal level. No gender differences were found on all subtests of KTK and also on total motor quotient. Although older players performed better on each test than their younger counterparts for the raw scores, no significant age effect was observed on motor quotient scores among different age groups.     

The role of a vertical reference point in changing gait regulation in cricket run-ups

The need to identify information sources which facilitate a functional coupling of perception and action in representative practice contexts is an important challenge for sport scientists and coaches. The current study investigated the role of visual information in regulating athlete gait behaviours during a locomotor pointing task in cricket. Integration of experiential knowledge of elite coaches and theoretical understanding from previous empirical research led us to investigate whether the presence of an umpire would act as a vertical informational constraint that could constrain the emergent coordination tendencies of cricket bowlers’ run-up patterns. To test this idea, umpire presence was manipulated during run-ups of 10 elite medium-fast bowlers. As hypothesised, removal of the umpire from the performance environment did not result in an inability to regulate gait to intercept a target, however, the absence of this informational constraint resulted in the emergence of different movement patterns in participant run-ups. Significantly lower standard deviation values of heel-to-crease distances were observed in the umpire condition at multiple steps, compared to performance in the no-umpire condition. Manipulation of this informational constraint altered gait regulation of participants, offering a mechanism to understand how perception–action couplings can be varied during performance in locomotor pointing tasks in sport.     

The effect of different goals and self-recording on self-regulation of learning a motor skill in a physical education setting

This study examined the effect of different goals (process, performance outcome, and multiple goals) and self-recording on self-regulation of learning a dart-throwing skill. Participants were 105 fifth and sixth graders who were randomly assigned to six (3 Goal type × 2 self-recording) experimental and one control group. Results showed a positive effect of self-recording on students’ performance, while no difference was found between the goal conditions. Moreover, goal group students made more technical attributions and adaptive inferences compared to the control group students. Results are discussed with reference to self-regulated learning, the pursuit of multiple goals and self-recording in physical education.     

基于模糊控制的直流调速系统调节器设计与仿真

利用模糊控制在非线性控制方面的突出优势,将之应用于直流调速系统,设计出模糊PI控制器,MATLAB仿真结果表明,该控制器能够有效提高系统性能,具有实际应用价值.