Reliability of the K-Force Muscle Controller Dynamometer on Eccentric and Isometric Hip Adduction Strength

Hip adduction strength tests are commonly used in clinical practice to provide an accurate diagnosis of groin injuries. Athletes with reduced adductor muscle strength are at risk of developing groin injuries. Our study aimed to evaluate the relative and absolute test-retest reliability of the side-lying eccentric hip adduction strength test and the long-lever adduction squeeze test using the K-Force hand-held dynamometer. Twenty physically active male individuals with a mean age (±SD) of 30.7 (±7.3) years were included. Both tests presented excellent test-retest reliability (Intraclass Correlation Coefficient: 0.77 - 0.95). The best and mean scores of the eccentric and isometric tests presented the smallest test-retest variation (MDC%: 12.8 - 14.9 and MDC%: 14.6 - 18.7, respectively). Our study showed that the K-Force dynamometer has excellent reliability for assessing hip adduction strength in two different testing positions. We suggest the best and mean of three repetitions for clinical practice as they present the lowest variability. Further research evaluating its clinimetric properties in different populations and gender is recommended.

Model Predictive Control Coupled with Artificial Intelligence for Eddy Current Dynamometers

The recent studies on Artificial Intelligence(AI)accompanied by enhanced computing capabilities supports increasing attention into traditional control methods coupled with AI learning methods in an attempt to bringing adap-tiveness and fast responding features.The Model Predictive Control(MPC)tech-nique is a widely used,safe and reliable control method based on constraints.On the other hand,the Eddy Current dynamometers are highly nonlinear braking sys-tems whose performance parameters are related to many processes related vari-ables.This study is based on an adaptive model predictive control that utilizes selected AI methods.The presented approach presents an updated the mathema-tical model of an Eddy Current Dynamometer based on experimentally obtained system operational data.Finally,the comparison of AI methods and related learn-ing performances based on the assessment technique of mean absolute percentage error(MAPE)issues are discussed.The results indicate that Single Hidden Layer Neural Network(SHLNN),General Regression Neural Network(GRNN),Radial Basis Network(RBNN),Neuro Fuzzy Network(ANFIS)coupled MPC have quite satisfying performances.The presented results indicate that,amongst them,GRNN appears to provide the best performance.

Robot driver for vehicle durability emission test on chassis dynamometer

A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.

Design and simulation of electrical dynamometer using improved DTC induction motor driver

AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for bench test systems. But, the speed and torque of induction motors are not easy to be controlled accurately. In this work, an electrical dynamometer based on the induction motor is proposed. In order to get better control performance of torque and speed of induction motor, an improved direct torque control method(DTC) is also developed based on the space vector modulation(SVM) technique. The performance of the proposed dynamometer system is validated in the Matlab/Simulink platform. The simulation results show that the new dynamometer has good torque and stator flux response. And the torque and stator current ripples of it are reduced significantly compared with using the conventional DTC method.

Test-retest strength reliability of the Electronic Push/Pull Dynamometer (EPPD) in the measurement of the quadriceps and hamstring muscles on a new chair

Background: Test-retest strength reliability of the Electronic Push/Pull Dynamometer (EPPD) in the measurement of the extensor and flexor muscles on a new constructed chair. The objective of the study was to assess reliability of Electronic Push/Pull Dynamometer in the measurement of the knee flexion and extension at 90° and 60° on a new constructed chair. The aims of the author: To assess reliability of Electronic Push/Pull Dynamometer in the measurement of the knee flexion and extension at 90° and 60° on a new constructed chair. Design: A test-retest reliability study. Subjects: One hundred healthy students male and female (mean age, 21y). Methods: Maximum isometric strength of the quadriceps and hamstring muscle groups was measured using the EPPD were recorded at 60° and 90° for 3 trials on 2 occasions. Reliability was assessed with the Intraclass correlation coefficient (ICC), mean and standard deviation (SD) of measurements, and smallest real differences were calculated for the maximum and for the mean and work of the 3 repetitions. Results: Mean strength ranged from 50.44 kg for knee flexion to 55.76 kg for knee extension 50.44 kg to 61.98 kg at 90° hip flexion. Test-retest reliability Intraclass correlation coefficients (ICCs) ranged from 0.85 to 0.99. ICCs for test-retest reliability ranged from 0.780 to 0.998. Conclusions: The results of the reliability study indicate that the EPPD in reliable dynamometer to use in determining lower limb muscle force production. It can be used to measure disease progression and to evaluate changes in knee extension and flexion strength at the individual patient level.

Soft measurement model on torque of alternating current electrical dynamometer including copper loss and iron loss

Alternating current electrical dynamometer is a common device to measure the torque of engines, such as the gasoline engine. In order to solve the problems such as high cost, high energy consumption and complicated measurement system which exists in the direct measurement on the torque of alternating current electrical dynamometer, copper loss and iron loss are taken as two key factors and a soft-sensing model on the torque of alternating current electrical dynamometer is established using the fuzzy least square support vector machine (FLS-SVM). Then, the FLS-SVM parameters such as penalty factor and kernel parameter are optimized by adaptive genetic algorithm, torque soft-sensing is investigated in the alternating current electrical dynamometer, as well as the energy feedback efficiency and energy consumption during the measurement phase of a gasoline engine loading continual test is obtained. The results show that the minimum soft-sensing error of torque is about 0.0018, and it fluctuates within a range from -0.3 to 0.3 N·m. FLS-SVM soft-sensing method can increase by 1.6% power generation feedback compared with direct measurement, and it can save 500 kJ fuel consumption in the gasoline engine loading continual test. Therefore, the estimation accuracy of the soft measurement model on the torque of alternating current electrical dynamometer including copper loss and iron loss is high and this indirect measurement method can be feasible to reduce production cost of the alternating current electrical dynamometer and energy consumption during the torque measurement phase of a gasoline engine, replacing the direct method of torque measurement.

Design and Manufacture of a Mobile Dynamometer

DIT has competed for a number of years in the Formula Student competition with petrol engine propelled vehicles.Dynamometer testing on these engines was traditionally outsourced.In2017/2018a decision was made to commence the design of an electric vehicle.Access to a suitable dynamometer for regular testing became more important than ever in order to fully characterise the electric motors the gearbox combinations and optimise the performance of the formula student electric vehicle.This paper deals with the design and manufacture and component selection for a mobile dynamometer that can accurately simulate racetrack conditions and apply typical loading cycles to a motor producing torque,power and speed values from a typical drivetrain.The dynamometer described uses a particle brake to apply the loads,a datum M425torque transducer to measure torque and a National Instruments LabVIEW interface to display and store data during testing.Safety is of vital importance and this paper describes the high-safety standards applied during the design and manufacture phase.With the implementation of an electronic control circuit,motor characteristics charts are produced,analysed and utilised for calibration and benchmarking for future motor test runs.Aim:Design&Manufacture of a mobile dynamometer unit to produce torque,speed and power values from the drive train of a motor.

压电式多维力传感器研究

针对传统压电测力仪有效测试区域有限、在不同测试位置输出结果不一致、扭矩值获取繁琐的等问题,基于传感器布置方式及石英晶片切型的特点,提出一种采用正八边形晶片的多维力传感器。在理论分析的基础上,通过计算仿真验证了正八边形晶片的设计合理性。对研制的多维力传感器进行了标定实验,标定结果显示:各传感器切向灵敏度高、各向线性及重复性好、向间干扰小,具有良好的测试性能。

内燃机试验对曲轴轴心轨迹影响的研究

内燃机台架试验时需要与测试设备连接,其中连接时的对中精度和连接方式直接影响试验质量。本文研究了不同对中精度对内燃机轴心轨迹的影响,确定了对中精度控制范围,通过试验过程振动与转速的对应关系测量,确认保养和连接方式影响,为内燃机开发试验过程的对中精度、保养和连接方案制定提供了参考依据。研究表明:对中精度超过0.5mm时可能会引起轴心轨迹偏离;试验过程定期保养可减少对中劣化的影响;高速内燃机应监测主轴承的振动情况,根据测量结果制定连接方案。

基于HSA-SVR的压电式车削测力仪多维力解耦

文中针对压电式多维力测力仪向间干扰大,制约测量精度的问题,分析了向间干扰对测力仪测量精度的影响,提出了一种基于支持向量回归机(SVR)的非线性解耦算法。利用混合模拟退火算法(HSA)对SVR进行参数寻优,对比并分析了HSA-SVR和线性最小二乘解耦法(LS)的解耦性能,证明经该方法解耦后向间干扰最大为0.526%,非线性误差最大为0.214%,HSA-SVR具有更好的非线性解耦效果。

基于小波变换的锚杆锚索测力仪设计

针对井下存在的电磁干扰,会对测力仪采集到的运放端的电压信号存在较大的干扰,进而对传感器测得的压力值准确性产生影响的问题;设计了基于小波变换的锚杆锚索测力仪。以国产HC32L176单片机作为主控芯片,对运放端的电压信号进行AD采集;选用合适的小波基函数、分解层数、阈值规则及阈值函数,对含噪信号进行分解,滤除不同层的高频成分,再对信号重构,得到去噪后的信号。Matlab仿真与实际测试结果表明:小波变换可以对采集的电压信号实现很好去噪,提高了锚杆锚索测力仪的可靠性与稳定性。

运动模型式飞行器气动力参数测试系统研究

为了对飞行器进行气动布局、飞行性能评估,提出了一种运动模型式气动力参数测量方法,并研制了一套运动模型式测试系统,通过运动模型来模拟飞行器在空气中的运动,其构造主要包含载具、测试支架、六分量天平、风速测量模块、数据采集模块、控制模块、便携计算机等部分;该类测试系统在某些特定工况下能准确模拟飞行器的飞行状态,对流场参数和模型所受载荷进行实时测量,预测各运动状态下飞行器的气动特性;通过数值模拟分析和风洞试验对车载试验数据进行了对比验证,结果表明,该测试系统能够准确获得模型的气动力特性数据;该系统具有一定的拓展性和通用性,可使用火箭橇等其他载具开展高速运动模型式气动力参数测量试验。

压电力传感器信号处理与采集系统设计

为解决旋转式压电测力仪电荷信号的处理和传输难题,设计了一套基于压电力传感器的信号处理与采集系统。设计基于ADA4530-1的信号调理电路实现传感器输出电荷信号的转换放大,基于STM32实现模数转换,采用蓝牙模块实现信号的无线传输,搭建基于LabVIEW的上位机软件进行力信号的采集。利用标准压电传感器对信号处理与采集系统进行实验测试,结果表明:信号调理电路模块的测量误差在0.2%以下,无线传输功能正常,上位机软件能够实时采集力信号数据,相对误差在0.5%以下,能够满足使用需求。

厚板搅拌摩擦焊多维动态压电测力仪研究

针对18mm厚2219铝合金搅拌摩擦焊过程焊接力变化范围大、速度快,导致难以准确测量的问题,设计了一种大量程四支点压电测力仪,主向100kN、侧向8 kN。经理论推导发现测力仪上板厚度及跨距是影响传感器输出的主要因素,利用有限元仿真对二者进行参数化分析,在满足现有测力单元量程基础上确定了其合理取值。最后对测力仪进行了静态标定、动态冲击实验,结果表明:测力仪线性度误差小于0.62%、向间干扰小于0.65%,固有频率大于1000Hz,达到了焊接过程跨尺度多维力测试精度要求。

男子赛艇运动员血浆代谢组学特征研究

为探究男子赛艇运动员的血浆代谢组学特征,采用高效化学同位素标记LC-MS技术对12名男子赛艇运动员测功仪2000m全力划前后的血浆差异代谢物和代谢通路进行分析。应用三层级代谢物鉴定方法对代谢物进行结构鉴定,结合主成分分析(PCA)、偏最小二乘法判别分析(PLS-DA)和火山图分析等筛选出差异代谢物,并将差异代谢物进行可视化聚类分析、KEGG注释与代谢通路分析。结果显示:男子赛艇运动员测功仪2000m运动后检测到423种可信度较高的代谢物,与运动前相比共筛选出26种差异代谢物发生了显著变化,其中17种显著升高(VIP>1,FC>1.5,P<0.05),9种显著降低(VIP>1,FC<0.67,P<0.05)。差异代谢物主要富集于牛磺酸和次牛磺酸代谢、泛酸盐和辅酶A生物合成、嘌呤代谢、嘧啶代谢和柠檬酸循环等生物代谢通路,其中,影响最大的是牛磺酸和次牛磺酸代谢。结论:男子赛艇运动员测功仪2000m运动前后血浆代谢组学特征发生了显著变化,抗坏血酸、半胱氨和3-亚砜-L-丙氨酸等多种氧化应激产物显著影响着赛艇运动员的运动表现,研究建议可将抗坏血酸作为赛艇运动员比赛或训练前后的重要营养补给,以提高运动能力和延缓疲劳造成的应激反应。

Investigation of performance and emission characteristics using ethanol-blended gasoline fuel as a flex-fuel in two-wheeler vehicle mounted on a chassis dynamometer

This study investigated the performance and emissions of flex fuels in a 110-cc BS6-compliant fuel-injected two-wheeler without ethanol adaptation adjustments.The tests were carried out under controlled conditions on a chassis dynamometer at 1000,2000 and 3000 r.p.m.using ethanol blends from 10%ethanol(E10)to 85%ethanol(E85).Parameters examined included brake power(BP)output,brake-specific fuel consumption(BSFC),peak in-cylinder pressure and exhaust temperature.Emissions,including carbon monoxide(CO),hydrocarbons(HC),nitrogen oxide(NOx)and unregulated emissions,were also assessed.As the percentages of the ethanol blend increased from E10 to E85,there was a noticeable improvement in power output.At 1000 r.p.m.,the BP ranged from 2.4 to 4.6 kW for different blends.The BSFC and the peak in-cylinder pressure followed a similar pattern,indicating enhanced performance and fuel efficiency with higher ethanol concentrations.Interestingly,using E85 at 1000 r.p.m.resulted in a significant 41.08%reduction in exhaust temperature compared with E10,although this difference decreased with higher blend percentages.Furthermore,replacing E10 with E85 at 1000 r.p.m.reduced CO and HC emissions by 9.17%and 38.34%,respectively.In contrast,NOx emissions increased at all r.p.m.levels with higher-ethanol blends,peaking at a 415 parts per million increase at 3000 r.p.m.However,unregulated emissions decreased significantly with increased r.p.m.and ethanol content.In summary,the use of flex-fuel blends in a two-wheeler resulted in a modest increase in BP output,improved fuel efficiency and lower CO and HC emissions.These findings are vital for optimizing ethanol blend utilization in two-wheeler engines under low-load conditions,considering both performance and environmental aspects.

Working condition recognition of sucker rod pumping system based on 4-segment time-frequency signature matrix and deep learning

High-precision and real-time diagnosis of sucker rod pumping system(SRPS)is important for quickly mastering oil well operations.Deep learning-based method for classifying the dynamometer card(DC)of oil wells is an efficient diagnosis method.However,the input of the DC as a two-dimensional image into the deep learning framework suffers from low feature utilization and high computational effort.Additionally,different SRPSs in an oil field have various system parameters,and the same SRPS generates different DCs at different moments.Thus,there is heterogeneity in field data,which can dramatically impair the diagnostic accuracy.To solve the above problems,a working condition recognition method based on 4-segment time-frequency signature matrix(4S-TFSM)and deep learning is presented in this paper.First,the 4-segment time-frequency signature(4S-TFS)method that can reduce the computing power requirements is proposed for feature extraction of DC data.Subsequently,the 4S-TFSM is constructed by relative normalization and matrix calculation to synthesize the features of multiple data and solve the problem of data heterogeneity.Finally,a convolutional neural network(CNN),one of the deep learning frameworks,is used to determine the functioning conditions based on the 4S-TFSM.Experiments on field data verify that the proposed diagnostic method based on 4S-TFSM and CNN(4S-TFSM-CNN)can significantly improve the accuracy of working condition recognition with lower computational cost.To the best of our knowledge,this is the first work to discuss the effect of data heterogeneity on the working condition recognition performance of SRPS.

Low-condensation diesel use contributes to winter haze in cold regions of China

The application of low-condensation diesel in cold regions with extremely low ambient temperatures(−14 to−29°C)has enabled the operation of diesel vehicles.Still,it may contribute to heavy haze pollution in cold regions during winter.Here we examine pollutant emissions from low-condensation diesel in China.We measure the emissions of elemental carbon(EC),organic carbon(OC),and elements,including heavy metals such as arsenic(As).Our results show that low-condensation diesel increased EC and OC emissions by 2.5 and 2.6 times compared to normal diesel fuel,respectively.Indicators of vehicular sources,including EC,As,lead(Pb),cadmium(Cd),chromium(Cr),nickel(Ni),and manganese(Mn),increased by approximately 20.2-162.5%when using low-condensation diesel.Seasonal variation of vehicular source indicators,observed at road site ambient environments revealed the enhancement of PM2.5 pollution by the application of low-condensation diesel in winter.These findings suggest that−35#diesel,a low-cetane index diesel,may enhance air pollution in winter,according to a dynamometer test conducted in laboratory.It raises questions about whether higher emissions are released if−35#diesel is applied to running vehicles in real-world cold ambient environments.

Handgrip strength in type 2 diabetics and nondiabetics:A comparative cross-sectional study among adults in rural Mysore

Objectives:The objective of this study is to assess the handgrip strength(HGS)in patients with type 2 diabetes,compare it with nondiabetes age-matched individuals,and assess the correlation between diabetic status and HGS among diabetic patients.Materials and Methods:A community-based cross-sectional study was conducted in rural Mysore,India,for 4 months.Fifty-eight clinically diagnosed type 2 diabetics and 58 nondiabetics participated in the study.The handheld dynamometer was used to test the HGS of all subjects in their dominant hand.Independent t-test was used to analyze the differences in HGS between patients with and without diabetes.Results:The mean dynamometer reading among diabetics was 19.08±7.51,whereas that in nondiabetics was 27.474±13.11.There was a significant difference in HGSs between diabetics and nondiabetics(P<0.01).Conclusion:Decreased muscle strength and quality in the upper extremities are associated with type 2 diabetes and can lead to functional and physical limitations.Diabetic patients’HGS should be evaluated promptly to identify any disabilities and plan for appropriate therapy.

孔面积变化对孔盘式水力测功器影响的数值分析

为了探究静转子孔面积变化对孔盘式水力测功器性能的影响,利用数值计算的方法,对现有孔盘式水力测功器在不同孔面积条件下的内部流动过程进行分析,得到水力测功器腔室内部的流场和温度场,对比水力测功器进出口温差、流量、扭矩以及吸收功率等参数的变化。结果显示:静转子孔面积的增加会导致水力测功器进出口温差的增大,且大致呈线性关系,而流量的变化幅度较小,维持在20%以内。扭矩与吸收功率随孔面积增加而增大,且增大幅度逐渐减小,孔面积变化的影响不断减弱。