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Background This randomized controlled trial evaluated the effect of radiofrequency ablation (RFA) of genicular nerve on muscle strength in osteoarthritis (OA) knee patients with chronic pain. Methodology Fifty-four patients with chronic knee OA, experiencing significant pain (visual numeric rating scale [VNRS] >50) and moderate to severe disease (Kellgren Lewis grade ≥2) were enrolled. Group 1 received RFA of genicular nerves of the affected knee while Group 2 received a sham procedure. The primary outcome was change in knee muscle strength evaluated using isokinetic peak torque (IPT) using IsoforceTM isokinetic dynamometer at 3 months. Secondary outcomes included changes in pain scores, function, perceived effect of the treatment and compliance to physiotherapy. Results At 3 months, significant difference was observed between IPT of flexor muscle at 60° and 180° between the treatment and the Sham control (P -value = .01). No significant difference was observed in the extensor muscle strength. Within-group analysis revealed a significant increase in the IPT values for both extension and flexion at 60°/sec and 180°/sec evident across various time intervals. Group1 consistently reported lower VNRS scores at all time points. Western Ontario and McMaster Universities Osteoarthritis Index scores of both groups were significantly different at all timepoints, with higher scores indicating reduced functionality in Group2. The Global Perceived Effect and compliance to physiotherapy were higher in Group1 patients at all times of follow up albeit decreasing trend in later periods. Conclusion Application of RFA to genicular nerves in chronic OA knee patients resulted in better pain relief, improved functionality, and increased muscle strength at extension and flexion at 3 months follow-up. Clinical Trial Registry of India — CTRI registration number CTRI/2020/05/025363. [ABSTRACT FROM AUTHOR]

The imperative need to advance the development of more efficient electric motors requires the meticulous measurement of small increments while minimizing the associated uncertainty in dynamometer tests. One of the key variables in such tests is the angular speed, which is typically obtained based on encoder measurements. This paper proposes a systematic measurement uncertainty assessment method based on the Guide to the Expression of Uncertainty for the two most widely used methods for angular speed measurement, namely, the frequency and period methods. In addition, the impact of the angular speed calculation method on the efficiency test uncertainty is assessed using an automatic test rig for electric motors. Our experimental results consider both steady-state and dynamic analyses. The results show that the period measurement method provides measurements with lower uncertainty for the encoders typically used in such test rigs, about 30 times less than the uncertainty determined for the frequency measurement method. Based on these results, the choice of a proper method can drastically decrease the angular speed uncertainty, and consequently the motor efficiency uncertainty, without increasing instrumentation cost.

The imperative need to advance the development of more efficient electric motors requires the meticulous measurement of small increments while minimizing the associated uncertainty in dynamometer tests. One of the key variables in such tests is the angular speed, which is typically obtained based on encoder measurements. This paper proposes a systematic measurement uncertainty assessment method based on the Guide to the Expression of Uncertainty for the two most widely used methods for angular speed measurement, namely, the frequency and period methods. In addition, the impact of the angular speed calculation method on the efficiency test uncertainty is assessed using an automatic test rig for electric motors. Our experimental results consider both steady-state and dynamic analyses. The results show that the period measurement method provides measurements with lower uncertainty for the encoders typically used in such test rigs, about 30 times less than the uncertainty determined for the frequency measurement method. Based on these results, the choice of a proper method can drastically decrease the angular speed uncertainty, and consequently the motor efficiency uncertainty, without increasing instrumentation cost. [ABSTRACT FROM AUTHOR]

Wheelchair ergometers are widely used in research, clinical practice, and sports environments. The majority of wheelchair ergometers are roller systems that allow for wheelchair propulsion in the personal wheelchair on one or two (instrumented) rollers. Oftentimes these systems are only statically calibrated. However, wheelchair propulsion is dynamic by nature, requiring a dynamic validation process. The aim of the current project was to present a low-cost portable system for the dynamic metrological verification of wheelchair roller ergometers, based on an instrumented reference wheel. The tangential force on the roller is determined, along with its uncertainty, from the reference wheel properties, and compared with the force measured by the ergometer. Uncertainty of this reference wheel system was found to be lower than the one of the ergometer used, indicating that this novel approach can be used for the metrological verification of ergometers. [ABSTRACT FROM AUTHOR]

Background and Purpose: Ankle muscle strength is an important criterion to consider and assess for return to play (RTP) after lateral ankle sprain (LAS). This study therefore focuses on the reported ankle muscle strength consideration for RTP by physicians and physiotherapists, both clinicians involved in RTP decisions, and how they assess it in daily practice. The primary aim is to compare reported clinical practice on ankle muscle strength evaluation between physicians and physiotherapists. Our secondary aims are: to assess the prevalence of use of qualitative versus quantitative assessment and; to determine if there are any differences in how clinicians with or without a Sports Medicine or Physiotherapy Education approach this assessment. Methods: A survey on RTP criteria after LAS was completed by 109 physicians in a previous study. A number of 103 physiotherapists completed the same survey. A comparison between clinicians' answers was realized and additional questions on ankle muscle strength were analysed. Results: Physiotherapists consider ankle strength for RTP more than physicians (p < 0.001). A large majority of physicians (93%) and physiotherapists (92%) reported assessing ankle strength manually and less than 10% use a dynamometer. Physicians and physiotherapists with Sports Medicine or Physiotherapy Education selected more quantitative assessment than those without (p < 0.001). Discussion: Despite being recognized as an important criterion, ankle muscle strength is not always part of the RTP criteria after LAS in daily practice. The dynamometers are scarcely used by physicians and physiotherapists, whereas it could accurately quantify ankle strength deficits. Sports Medicine or Physiotherapy Education increases the use of quantitative ankle strength assessments by clinicians. [ABSTRACT FROM AUTHOR]

Rod pumping systems typically require the analysis of dynamometer cards for fault diagnosis. While external instrumentation assists in obtaining these cards, it simultaneously raises monitoring costs and complexity. To address this issue, this paper introduces a parameter estimator that integrates the equivalent circuit model of an induction motor with the beam pumping unit model. We have compared the performance of two practical estimators, utilizing the terminal quantities of the driving motor as inputs. The results demonstrate surface dynamometer cards under varying operational conditions of the oil well. By augmenting the estimator’s input variables, the estimated cards align more closely with the actual ones. This practical application proposes an alternative method for acquiring the surface dynamometer card, which can function as a supplementary approach in fault diagnostics and contribute to informed maintenance decisions for the pumping unit.

A force transducer-based plate dynamometer for milling force measurements is presented in this paper. The main components of the designed dynamometer were described, and experimental modal analysis was carried out while considering the dynamometer as a 1DOF system. The values of the main components of the 1DOF systems such as mass, damping coefficient, and equivalent stiffness were identified, and the natural frequency for rings and dynamometer was calculated. The calculated natural frequencies of components were found in reacceptance FRF, obtained by modal analysis done with an impact hammer. A MATLAB simulation was done to validate the system using the transfer function based on the modal test. [ABSTRACT FROM AUTHOR]

The dynamometer card (DC) is crucial for the remote monitoring of the sucker rod pumping system (SRPS). However, the DC sensors have poor real-time performance and high maintenance costs leading to difficulties in obtaining datasets of the downhole working states from different oil wells. Moreover, the motor power curve is easy to obtain in real-time and can reflect the changes in pumping unit load. Thus, this paper proposed a novel hybrid model for indirect measurement DC based on measured motor power. Firstly, based on the mechanical model analysis of SRPS, the dataset is constructed by transforming the motor power and geometric parameters of the SRPS into the polished rod torque, the first-derivative of polished rod torque, the second-derivative polished rod torque, and the torque factor. These four parameters are merged as the inputs of the data-driven model. Subsequently, a data-driven model implements the particle swarm (PSO) algorithm to optimize the weights and thresholds of the Back Propagation (BP) neural network model, which was trained to predict DCs of three common working states. Finally, the proposed method is verified experimentally through the measured DC and motor power data. Both experimental and prediction results demonstrate the effectiveness of the proposed method for generating DC. The mean DC area relative error of the hybrid method proposed in this paper is 2.52%. [ABSTRACT FROM AUTHOR]

In performance tests, replacing humans with robotic drivers has many advantages, such as high efficiency and high security. To realize the vehicle speed tracking control with a robotic driver, this article proposes a novel deep reinforcement learning (DRL) approach based on deep deterministic policy gradient (DDPG). Specifically, the design of the approach includes state space, action space, reward function, and control algorithm. Then, to shorten the training time, the proposed approach utilizes the basic fundamental relationship between vehicle speed and pedal opening to intervene in network exploration. Furthermore, to solve speed fluctuations in low-speed sections, the replay buffer is optimized by adding weighted training samples. Experiments are conducted on fifteen cars, and results show that the proposed algorithm can effectively control the vehicle speed. Generally, it only needs three or four episodes of training to meet the requirements. Compared with the Segment-PID method, the proposed method has a smoother speed and fewer overbound times. Note to Practitioners—This article was motivated by the algorithm of deep reinforcement learning (DRL), which can be applied to automatic control including vehicle speed tracking control with a robotic driver. With the complexity, the delay of the vehicle model, and the dead zone of the pedal, it is difficult for existing classic control theories to achieve satisfactory vehicle speed tracking. This article analyzes the mathematical model based on the DRL theory and the vehicle dynamic model, then builds the speed tracking controller based on the deep deterministic policy gradient (DDPG) algorithm, and makes corresponding optimizations for the problems in the experiment. Through the control software integrated with the DDPG algorithm, the operator can easily realize the training and testing of the neural network, which greatly reduces the time and cost of vehicle testing and is of great significance to the emission certification of new vehicles. [ABSTRACT FROM AUTHOR]

Since a large amount of data can be obtained in the oil production process nowadays and the operation environment is increasingly complicated, it is necessary to research unsupervised and robust fault detection methods for improving safety. In this paper, an online Bayesian-based technique with a novel decision fusion algorithm is proposed for unsupervised fault detection in the pumping unit. First, a new strategy to detect the working condition of the pumping unit by dynamometer card as well as five process measured variables is proposed. To deal with high-dimension data and outliers in dynamometer card, a robust Douglas-Peucker algorithm is developed for obtaining compressed data. A chord ratio index evaluating deviation degree of observations is defined, which can be used for removing outliers during approximation. Two norms are introduced for choosing the threshold in the proposed Douglas-Peucker algorithm. Moreover, a Bayesian-based online change point detection model is attempted for detecting univariate faults in the pumping unit. A decision fusion method derived from Bayesian probability formula is proposed for fusing univariate fault detection results. At last, the power of the proposed method is evaluated by numerical simulations and a real oil production process. [ABSTRACT FROM AUTHOR]

In this article, a new approach for combustion engine test bed system identification is presented. Modern engine test beds are used to reduce development time by utilizing them for hardware-in-the-loop tests. For highly accurate and close-to-reality tests, model-based controllers are deployed, which rely on precise models of the test bed. Hereby, the main challenge is the unknown, cyclic disturbance of the engine due to compression and combustion of the air-fuel mixture. These disturbances also occur when the throttle is kept at zero and have a big impact on the measurements. Therefore, parameter estimation is strongly impeded. A method for dealing with these disturbances and embed them into the identification procedure in a two-step fashion is presented in this contribution. Further advantages of this new approach are that a physical model is obtained, but prior knowledge of parameters is not necessary. Moreover, disassembling of the test bed to perform separate parameter estimation is not needed and hence, the time consumption of the procedure is kept low. Experimental results on a 4-cylinder diesel engine test bed prove the feasibility and effectiveness of the proposed concepts. [ABSTRACT FROM AUTHOR]

The modern methodology for quantifying the quality of experimental data is uncertainty analysis. Current methods are reviewed with some examples primarily from naval hydrodynamics. The methods described apply to fluids engineering. The history of uncertainty analysis, U.S. and international standards on uncertainty analysis, verification and validation standards for computational fluid dynamics, and instrument calibration are discussed. One important result is that random loading in force calibration can produce a lower uncertainty estimate than sequential loading. Statistically, the calibration results for the slope and intercept are the same for the two methods in the example thrust calibration, but the uncertainty in random loading is a factor of three smaller than sequential loading. [ABSTRACT FROM AUTHOR]

This publication introduces the downhole dynamometer sensor technology for digitalizing sucker rod pumps’ downhole behavior. The presented field application enables insight into the sensor principles, data evaluation processes and highlights the value chain. Sucker rod pumps (SRP) are used worldwide since the last century. Nevertheless, the system is still prone to fail in certain situations. The lack of measured downhole data is a severe problem that significantly slows down the innovation process. The presented downhole dynamometer sensor measurement system can successfully fill this gap and provides valuable, requested information. Each downhole dynamometer sensor records the three-dimensional stress field, the movement characteristics, and the produced fluid temperature. The recorded data allow a critical evaluation of the rod string behavior. Rod string loading and movement, friction forces between rod guides and tubing, and volumetric parameters can be evaluated. The recordings of several sensors are linked together to provide a comprehensive picture of the sucker rod string condition. The field case data analysis has indicated severe wear at specific positions of the sucker rod string and shown a significant optimization potential of the system. This publication shows the significant optimization potential for the tested sucker rod pumping system to postpone the economic limit and increase the recovery factor. The novelty is the wealth of information obtained and the associated detailed evaluation possibilities. [ABSTRACT FROM AUTHOR]

Objectives. The purpose of the study is to develop dynamometric equipment for measuring the components of cutting forces when processing materials with an axial tool in a dynamic mode.Methods. The study is based on the application of electrical methods using piezoelectric and strain gauge transducers, whose main advantage is the ability to register and record fast-moving dynamic processes.Results. Based on an analysis of existing dynamometers, the necessity of developing a new modern dynamometer device, which would allow the oscillations of the cutting force components to be registered and recorded in dynamic mode, is justified. The advantages of using strain sensors for a dynamometer are described. An analysis of the selected dynamometer design indicated that the sensors for measuring the axial forces and torque are located on one elastic element, which affects the accuracy of their measurement due to their mutual influence. Therefore, it was necessary to place them on different elastic elements. The developed and manufactured dynamometric equipment for carrying out the research work in the field of axial tools for processing materials is presented. The relative measurement error is calculated.Conclusion. The dynamometric equipment makes it possible to record the periodic and quasiperiodic oscillations of two components of the cutting forces without distortion for various tapping, drilling and countersinking processes, occurring at a frequency of up to 1500 Hz in real time mode, and can be used to optimise the cutting parameters. Using the dynamometric equipment, it is possible to register the signals from up to 8 force sensors in real time, amplify signals, transform the signal from analogue to digital, visualise data and print out the results of experimental data. The equipment is suitable for use in research laboratories of machine-building enterprises, universities and other scientific institutions.

A magnetic resonance (MR) compatible ergometer has been developed to study contracting lower limb muscles during acquisition of MR spectroscopy data, a technique to noninvasively measure metabolic energy in muscle tissue. Current active and passive MR-compatible ergometer designs lack torque or velocity control to allow precise mechanical measurements during isotonic and isokinetic contractions; incorporating load and velocity controllers while maintaining MR-compatibility is the main challenge. Presented in this paper is the design and evaluation of an MR-compatible ergometer designed to control knee torque or velocity up to 420 N·m and 270 deg/s and is able to operate in a 3 Tesla magnetic field. The ergometer comprising of a passive component with no electronics or ferrous materials is located inside the bore of the scanner. The active component with the electronics and actuator located outside of the magnetic field in an adjacent room. The active components connect to the passive components via a cable that passes through the waveguide, a hole in the wall of the scanner room. System evaluations were performed and human subject evaluations were performed that measured the mechanical performance and show the mean percent errors below 9% in isotonic and 2% in isokinetic conditions. [ABSTRACT FROM AUTHOR]

Thrust testing units with a piezoelectric dynamometer have unique traits such as excessive stiffness, tremendous measurement accuracy, dynamic performance and no hysteresis. These are widely used in the applications requiring force/thrust measurements in the aerospace industry and high‐end tool condition monitoring. The performance of these units is necessary to be evaluated. In this study, an improved layout of six‐degree of freedom force/thrust measurement stand is proposed and analysed theoretically and experimentally. The measurement stand is a structural component to measure six components of force, such as axial force/thrust (FX, FY, and FZ) and other components (MX, MY, and MZ). Test stand consists of seven piezoelectric sensors in two sections. The front part consists of four piezoelectric force sensors, while the rear part consists of three sensors. The rear section is hexagonal, with three sensors mounted at 120°. The measurement stand can measure the principal force/thrust up to 50,000 N. A mathematical model is derived for every sensor against forces in all directions. To calibrate the stand, a calibration platform is designed and fabricated. The calibration platform can generate a range of forces/moments. Calibration experiments verifies that the measurement stand is fairly functional to measure variety of forces/moments with high repeatability. [ABSTRACT FROM AUTHOR]

This paper presents the methodological and technical aspects of the implementation of a hardware-in-the-loop experimental setup, suitable to simulate the dynamics of a floating system in wind tunnel experiments. The presented work is based on the specific application of a floating offshore wind turbine scale model, even if the approach holds also for floating systems in general, being subjected to the simultaneous action of wind and waves. The setup is based on a two degrees-of-freedom system, providing the motion of the floating system along surge and pitch. With reference to the implementation of the HIL test methodology the following topics are thoroughly analyzed: scaling issues, numerical issues, mechanical system characterization, force corrections, measurement, and signal processing. For each of these topics the methodological approach is presented, and the technical issues are described. A subset of results is then reported to show the effectiveness of such experimental apparatus, for different sea states: still water, regular, and irregular waves. [ABSTRACT FROM AUTHOR]