不同运动项目运动员髋关节屈伸肌群横断面积与力矩特征的相关研究

通过对足球、速度滑冰运动员髋关节屈伸肌群横断面积及力学相关指标的测定,探讨不同运动项目的运动员髋关节屈伸肌群形态特征与肌肉收缩效应的特点以及两者间的内在规律,为运动员训练水平的评估及科学选材等提供理论指导。肌肉横断面积采用螺旋CT进行断层扫描,影像分析采用MoticImagesAdvanced3 0测试系统软件,力量测试采用美国Cybex Norm等速测力系统,数据处理采用SPSS 8 0软件。结果表明:足球运动员大腿肌肉横断面积大于速滑运动员,差异主要表现在股四头肌和股后肌群。在相同测试速度下,足球与速度运动员髋关节屈伸时,左右两腿肌肉收缩力量无明显差异。但不同项目间,同一肌群在不同关节运动,不同速度下,则表现出肌肉力量的明显不同。髋关节屈伸运动时,股四头肌与股后肌群横断面积与力矩的相关程度,足球以屈为明显,速滑以右伸为明显。     

Implementation of a new PC based controller for a PUMA robot

This paper describes the replacement of a controller for a programmable universal machine for assembly (PUMA) 512 robot with a newly designed PC based (open architecture) controller employing a real-time direct control of six joints. The original structure of the PUMA robot is retained. The hardware of the new controller includes such in-house designed parts as pulse width modulation (PWM) amplifiers, digital and analog controllers, I/O cards, signal conditioner cards, and 16-bit A/D and D/A boards. An Intel Pentium IV industrial computer is used as the central controller. The control software is implemented using VC programming language. The trajectory tracking performance of all six joints is tested at varying velocities. Experimental results show that it is feasible to implement the suggested open architecture platform for PUMA 500 series robots through the software routines running on a PC. By assembling controller from off-the-shell hardware and software components, the benefits of reduced and improved robustness have been realized.     

轧制扭矩的现场测试

轧制扭矩的计算公式均为经验和半经验公式，计算结果与实际相差较大，为取得轧制扭矩的精确值，必须对轧机进行实际的测试。对实测数据的分析，有利于挖掘轧机机组的生产潜力，为节能降耗创造条件。     

对《人体生理学》教材中"肌肉收缩形式"的分析探讨

对高校体育专业《人体生理学》教材中学生比较难掌握的"肌肉的收缩形式"一节内容进行探讨分析,认为教材对等张收缩、等动收缩等名词下的定义不完全或不妥当,不利于体育专业学生理解,并对如何掌握这几种收缩形式提出自己的见解。     

数控机床主传动无级调速系统设计方法探讨

根据机床主传动所需的功率转矩特性和调速电机的功率转矩特性，分析了无级调速系统的设计方法，并对几种情况的计算作了分析。     

TY220推土机变速箱、变距器故障原因分析

分析TY220推土机变速箱、变距器泄漏、磨损和油温过高的原因,介绍其危害,并针对每一种故障提出相应的修复措施.     

优秀田径运动员腘绳肌拉伤后的肌力特征分析

运用CYBEX-Norm型等速肌力测试与康复系统,以上海市优秀田径运动员为研究对象,探讨腘绳肌拉伤后的等速参数变化,分析伤后的恢复情况.结果显示：受伤运动员伤侧腘绳肌峰力矩角度明显增大,表明拉伤腘绳肌达到最大力量的时间明显延长,最大收缩长度发生了改变.建议：在运动实践中,合理运用等速测试的峰力矩角指标作为腘绳肌拉伤后恢复效果的监控指标,并结合适当比例的离心训练,将有助于减少运动中腘绳肌的拉伤.     

The fatigue effect of a simulated futsal match protocol on isokinetic knee torque production

The objective of this study was to investigate the effects of a simulated futsal match protocol on isokinetic knee torque production. Twenty-one young futsal players participated in this study and performed a futsal-specific protocol comprising two blocks of 20-minute activities to simulate the match demands. At pre-protocol, half-time, and post-protocol, the concentric and eccentric isokinetic peak torque of the knee flexor and extensor muscles, the angle of peak torque, and the conventional and functional torque ratios were assessed. ANOVA was used to compare the variables (significance level p < 0.05). A decrease of knee flexor and extensor eccentric torque and knee flexor concentric torque was found, in which the pre-protocol levels were higher than those at half-time, with both being larger than those at post-protocol. The knee extensor concentric torque reduced at half-time. The angle of eccentric torque of knee flexors increased, and the conventional and functional torque ratios decreased at post-protocol. In conclusion, the protocol produced a time-dependent reduction of knee flexor and extensor torque in both concentric and eccentric actions. These findings suggested a possible impairment of performance and the emergence of risk factors for hamstring strains during a futsal match.     

电动助力转向转矩传感器研究现状及发展趋势

介绍了汽车电动助力转向系统转矩传感器的基本原理,对现阶段出现的各类型的转矩传感器进行了结构及原理分析,并对各类转矩传感器的优缺点进行了总结。提出了现阶段最适合用于汽车电动助力转向系统的转矩传感器,展望了转矩传感器未来的发展趋势,为设计开发性价比高的传感器提供一个理论基础。     

一种直流力矩电机精确控制的新方法

针对直流力矩的闭环调速控制,提出一种渐近调速算法,主要解决调速过程的快速、平稳、精确控制问题.介绍算法,并给出实现这一算法的技术方案.方案以数字信号处理器为核心,与集成马达控制器和锁相倍频测速单元共同组成闭环随动控制系统.给出驱动控制通道设计和速度反馈通道设计,并对测速单元的测量方法做出精度分析.