Fused Ultrasound And Electromyography-Driven Neuromuscular Model To Improve Plantarflexion Moment Prediction Across Walking Speeds

Background: Improving the prediction ability of a human-machine interface (HMI) is critical to accomplish a bio-inspired or model-based control strategy for rehabilitation interventions, which are of increased interest to assist limb function post neurological injuries. A fundamental role of the HMI is to accurately predict human intent by mapping signals from a mechanical sensor or surface electromyography (sEMG) sensor. These sensors are limited to measuring the resulting limb force or movement or the neural signal evoking the force. As the intermediate mapping in the HMI also depends on muscle contractility, a motivation exists to include architectural features of the muscle as surrogates of dynamic muscle movement, thus further improving the HMI's prediction accuracy. Objective: The purpose of this study is to investigate a non-invasive sEMG and ultrasound (US) imaging-driven Hill-type neuromuscular model (HNM) for net ankle joint plantarflexion moment prediction. We hypothesize that the fusion of signals from sEMG and US imaging results in a more accurate net plantarflexion moment prediction than sole sEMG or US imaging. Methods: Ten young non-disabled participants walked on a treadmill at speeds of 0.50, 0.75, 1.00, 1.25, and 1.50 m/s. The proposed HNM consists of two muscle-tendon units. The muscle activation for each unit was calculated as a weighted summation of the normalized sEMG signal and normalized muscle thickness signal from US imaging. The HNM calibration was performed under both single-speed mode and inter-speed mode, and then the calibrated HNM was validated across all walking speeds. Results: On average, the normalized moment prediction root mean square error was reduced by 14.58 % (p = 0.012) and 36.79 % (p < 0.001) with the proposed HNM when compared to sEMG-driven and US imaging-driven HNMs, respectively. Also, the calibrated models with data from the inter-speed mode were more robust than those from single-speed modes for the moment prediction.Conclusions: The proposed sEMG-US imaging-driven HNM can significantly improve the net plantarflexion moment prediction accuracy across multiple walking speeds. The findings imply that the proposed HNM can be potentially used in bio-inspired control strategies for rehabilitative devices due to its superior prediction.

Sensorless Speed Contorl of Doubly-Fed Induction Machine Using Reactive Power Based MRAS

A sensorless speed control method for doubly-fed induction machine (DFIM) operating with constant frequency but in variable speed mode is presented in this project work. The control method is based on rotor speed estimation technique by a reactive power model reference adaptive system (MRAS) observer. The presented technique does not depend on any kind of flux evaluation and also independent to the resistance variation of either stator or rotor. The MRAS observer has a capacity for speed catching operation. PI controller is designed and also optimized using algorithm for better dynamic behaviour of the machine. MATLAB Simulink model and the simulation results are shown to check the effectiveness of the observer and also of the controller.

INCREASING THE COMFORTABILITY OF THE VEHICLE DURING ACCELERATION BY IMPROVING THE DESIGN AND CONTROL METHODS OF THE MOTOR-TRANSMISSION UNIT

The derivative of acceleration with respect to time is used to evaluate and ensure driving comfort during acceleration and deceleration. Frequent and rapid changes in acceleration means frequent and rapid deformation, which can lead to the destruction of the load. The article proposes to minimize the amount of acceleration due to the rational choice of transmission ratios in intermediate gears and the law of changing the engine torque. The use of continuously variable transmissions allows you to solve the problem by choosing a rational law for changing the gear ratio of the transmission. The method of selection at the stage of car design of the maximum effective engine power and transmission ratio in top gear is proposed, taking into account the improved formula for calculating the aerodynamic resistance to motion. The required laws of change in the efficiency of the torque and engine power have been determined. The use of a continuously variable transmission allows the engine to operate at a constant high-speed mode and provides control over the acceleration of the car by changing the fuel supply. It is determined that the engine power expended on the movement with the adjustment of the acceleration of the car will be less than with unregulated acceleration if the exponent at the speed of the car, obtained experimentally, is less than one. Keywords: car; comfort; continuously variable transmission; motor-transmission unit; power; overclocking; aerodynamic resistance; gear ratio

Optimization of international road transportation of cargoes in the management of enterprises of agricultural sector and road transport enterprises

To enhance the efficiency of management of enterprises in the agricultural sector, it is necessary to improve logistic processes of delivery of livestock and crop production in the implementation of international road transportation. Delivery of cargo "just in time" is very important, so transportation time planning is relevant and allows reducing costs. The process of planning the delivery of perishable goods was described. The spread of the required time is presented for transportation with a varied degree of stochasticity. It was found that the specifics of customs clearance affect the availability of a certain minimum time required for such a procedure. The time of customs clearance of cargo and delay time affect the deadline for cargo registration in international road transportation. The widest spread of time is observed by the procedure of customs clearance of cargoes that takes from 12 to 25 hours, and the probability of customs clearance is only 0.435. Accordingly, this affects a decrease in indicators of "just in time" delivery. The functional dependence of the probability of transit time not exceeding the planned time was compared, depending on the data of the specified route. Based on probabilistic analysis, the possibility of unplanned deviations from the estimated terms of each stage was taken into account and the optimal set of time intervals, which allow obtaining the optimal probability of "just in time" delivery, was proposed. The total cargo delivery time does not change. The recommendations on formulating the requirements for road transport enterprises were given. Namely, to strengthen the requirements for the time of cargo transit. These requirements include the average speed of motion, the choice of appropriate transport, planning the route in terms of the speed mode of highways, etc.

Influence of the circumferential speed of the spiked cylinders on the efficiency of cleaning raw cotton

The article examines the dependence of the speed of rotation of the spiked cylinder of the machine for cleaning the raw cotton from fine impurities on the cleaning efficiency of the machine by different varieties. In addition, the article plotted the speed of rotation of the spiked cylinder as a function of mechanical damage to the seed. Based on experimental studies, the operation of the machine for cleaning cotton raw materials from fine contaminants is based. Experimental studies on raw cotton of medium and fine fiber varieties of hand and machine cotton picking on the value of constant and differentiated peripheral speeds of cylinders fully confirmed the theoretical conclusions. It is recommended to use a differentiated high-speed mode of rotation of the spiked cylinders: When cleaning medium-staple cotton - 10:11:12 m/sec, when cleaning fine-stapled cotton - 9:10:11 m/sec.

Domestic Retrofit Assessment of the Heat Pump System Considering the Impact of Heat Supply Temperature and Operating Mode of Control—A Case Study

In this study, performance assessment of the variable speed compressor-based air source heat pump (ASHP) system as a domestic retrofit technology instead of fossil fuel-based heating technologies for the 1900s Mid terraced house is investigated. The assessment was conducted considering operating mode of control and heat supply temperature impact of the system. In the literature, ASHP system experimental development with variable speed mode (VSM) of control in comparison to fixed speed mode (FSM) of control at low to medium and high heat supply temperature in the context of UK was found with very limited number of studies, but without considering retrofit application. The focus of the earlier studies was on the individual components and performance improvement. The designed heat pump (HP), developed, and tested at constant heat load, simulating the real domestic heat demand under the controlled laboratory conditions and numerical modeling is utilized for the analysis purposes. The HP performance, energy demand, carbon emissions, and cost varies significantly due to changing heat supply temperature (35 °C, 45 °C, and 55 °C), control mode and accordingly the carbon emission and cost savings are achieved. The oil and gas boilers ranges from conventional to highly efficient type and evaluated in terms of annual running cost, energy consumptions, and carbon emissions in comparison with the HP system. Additionally, a comparative study with the existing retrofitted very high temperature ASHP inside the house is conducted. The developed HP at 55 °C could not defeat the very high heat supply temperature HP system (75 °C supply temperature) in performance and cost savings but become attractive at low supply temperature (35 °C). The HP system in VSM at low heat supply temperature instead of gas boiler (90% efficiency) could cut the annual carbon emissions by 59% but with additional 6% running cost for the Mid terraced test house in Belfast climatic conditions.

Design and verification of slip rate control system for straight line travel of high clearance self-propelled sprayer

A slip rate control system aimed at improving the working efficiency and driving stability of a high clearance sprayer was developed. First, the two-pump, two-anti-slip control (ASC) valve, four-motor “X” drive scheme hydraulic slip rate control system was designed, and a mathematical model of the system as well as a vehicle dynamics model were established. The system includes a slip rate control strategy, a proportional-integral-derivative control method and a fuzzy adaptive proportional-integral-derivative sprayer control method. To verify the performance of the system, a simulation model was developed using MATLAB/Simulink, and the performance of the two control methods were compared. Additionally, an actual vehicle test platform was built based on 3WPG-3000 high clearance self-propelled sprayer independently developed by the research group. The simulation results revealed that when a wheel slipped, the slip rate control system was able to control the wheel slip rate and keep it within the threshold value of 0.1, thus meeting the operating requirements of the sprayer. The field test results revealed that in field operations with a low adhesion coefficient, the system was able to maintain a nearly unchanged wheel speed in both fixed speed mode and variable speed mode, maintaining a slip rate below the target of 0.1 “when in a straight running mode” in both cases. Altogether, the results of the simulation and field test verify the stability, accuracy, and practicability of the system.

Study of the Quality of Barley Cleaning with Indented Cylinder from Grain Impurities

Results of the study on the separation of crushed barley grains from the grain mixture along the length of the cell surface of indented cylinder, depending on the initial impurity concentration (Zi), the speed mode of the indented cylinder (n) and the lifting angle of the upper edge of the front wall of the output tray (γn) relative to the horizon, are presented. The theoretical steadily decreasing trend in the intensity of the impurity component separation has been experimentally confirmed. The fact that crushed barley grains are a difficult-to-separate impurity has been established. When n increases, the intensity of impurity separation increases dramatically. The γn angle increases the dependence of the process dynamics on the speed mode. At γn =55°, the increase of n from 40 to 50 rpm increases the intensity of impurity separation from the grain mixture by 6.44 times. A decrease in the value of γn and an increase in the speed mode of operation lead to an increase in process losses. An increase in the initial contamination of the grain mixture under other equal operating conditions of the indented cylinder leads to a proportional increase in its residual contamination.

Advanced Control Method of 5-Phase Dual Concentrated Winding PMSM for Inverter Integrated In-Wheel Motor

This paper presents some techniques for driving novel 5 phase dual winding PMSM (Permanent Magnet Synchronous Motor) for the in-wheel motor. The motor realizes winding change over characteristics that can expand driving area from high-torque mode to high-speed mode due to the dual winding construction. However, the dual winding structure makes a high-current ripple due to high coupling between windings. The paper proposes some control methods to reduce the current ripple, including inverter career ripple. The paper also presents harmonics current injection, such as the 3rd harmonics current injection method, to reduce the torque ripple and generate higher torque.

Dynamics and Quality of Trieur Separation of Millet Seeds from Barley

Представлены результаты исследований физико-механических свойств компонентов зерносмеси, динамики и качества выделения примеси из неё в зависимости от скоростного режима работы триера (n) и угла подъёма верхней кромки передней стенки выводного лотка (γn). Подтверждён лавинообразный характер выделения проса из ячменя в первых интервалах времени измерений за счёт эффекта динамической сегрегации примеси в циркулирующих слоях зерносмеси. Положительный вектор сегрегации проса (вниз – к ячеистой поверхности) объясняется значительной его насыпной плотностью, гладкой поверхностью – угол естественного откоса составляет 20,3° (в 1,8 раза меньше, чем у ячменя), компактными размерами зерновок и их округлой формой. Установлена высокая степень влияния на интенсивность выделения примеси скоростного режима – при приросте n на 12,5% (от 40 до 45 об/мин) выделенная масса примеси в первом интервале времени измерений (tи = 5 с) увеличилась на 125%. При γn= 35° степень выделения примеси (и остаточная засорённость) обеспечиваются на высоком уровне стандартной длиной ячеистого цилиндра (l = 2,2 м) во всём диапазоне скоростного режима работы стенда n = 40…55 об/мин. С ростом γn до 45º сужается диапазон скоростного режима работы по качественным показателям до n = 45…55 об/мин, а при γn= 55º качество работы обеспечивается только при n = 50…55 об/мин. При γn= 45…50º и n = 50…55 об/мин 100%-ное выделение примеси обеспечивается за 30…35 с смещения сегмента зерносмеси по длине ячеистого цилиндра. При этом его рабочая длина используется лишь на 55…64%. Технологические потери на всех исследуемых режимах работы не превышают 0,3% и носят случайный характер, что объясняется неопределённостью условий выброса зерновок ячменя ячеями. The research results of physical and mechanical properties of grain mixture components, dynamics and quality of impurity extraction from it are presented depending on the speed mode of operation of the trieur (n) and the lifting angle of the upper edge of the front wall of the lead tray (γn). Avalanche-like character of millet separation from barley in the first intervals of measurement time is confirmed due to effect of dynamic segregation of impurity in circulating layers of grain mixture. The positive vector of millet segregation (down to the cellular surface) is explained by its significant poured density, a smooth surface – the angle of friction is 20.3° (1.8 times less than that of barley), compact bruchid sizes and their rounded shape. A high degree of influence on the rate mode impurity release intensity was established – at an increase of n by 12.5% (from 40 to 45 rpm), the extracted impurity mass in the first measurement time interval (tи = 5 s) increased by 125%. At γn = 35°, the degree of impurity release (and residual content of impurities) is provided at a high level by the standard length of the cellular cylinder (l = 2.2 m) in the entire range of the speed mode of the bench n = 40...55 rpm. With an increase in γn to 45º the range of the high-speed mode of operation is narrowed to n = 45...55 rpm, and at γn = 55º the quality of operation is ensured only at n = 50...55 rpm. At γn = 45...50° and n = 50...55 rpm 100% impurity release is ensured by 30...35 second with displacement of the grain mixture segment along the length of the cellular cylinder. At the same time, its working length is used only on 55...64%. Technological losses in all investigated modes of operation do not exceed 0.3% and are random in nature, which is explained by the uncertainty of the conditions for the release of barley bruchids by cells.