Traction Force Research Articles

Retinal hemorrhages and damages from tractional forces associated with infantile abusive head trauma evaluated by wide-field fundus photography

We evaluated the distribution and types of retinal hemorrhages (RHs) and other damages in eyes with abusive head trauma (AHT). This retrospective, consecutive case series of AHT and non-AHT conditions involved 54 children with AHT, 43 children with head bruises, and 49 children with blunt eye trauma, each of non-AHT supported by reliable witness accounts. RHs and other damage were evaluated using ophthalmoscopy and wide-field fundus photography. A variety of RH types and other damage were identified in the AHT group but not in the non-AHT group. RHs in AHT extended from the posterior pole to the far periphery in 77% of eyes and on/near the veins in 86% and arteries in 85%, most of which were in the far periphery. Retinoschisis, white-dot lesions, and retinal folds were seen even in the far periphery. RHs on/near the veins and arteries, retinoschisis, and retinal folds suggest a traumatic mechanism of the tractional force of the vitreous that is attached to the entire retinal surface. Identifying the distribution and arterio and venous origins of RHs is a key factor in determining the association with trauma. Thus, wide-field fundus photography is useful to record and evaluate the origin of the RHs and other retinal damage.

Application of a group of ground-based robotic means as a modular means of evacuation of equipment

The possibilities of improving the means of evacuation of general and special purpose vehicles on a wheeled and tracked platform have reached technological limits. The prospects for further development of evacuation facilities are associated with their construction on a modular principle. A group of ground-based robotic means, generally heterogeneous, can be used as evacuation vehicle modules. In relation to a group of homogeneous robotic means, a method has been developed for calculating the required number of them to achieve the necessary trac-tion force, taking into account the significant variability of possible physical-geographical and road-ground condi-tions. The obtained results of mathematical modeling allow us to conclude about the high efficiency of the use of modular means of evacuation of equipment.

Contributions of the Abductor Muscles to Rotational and Distractive Stability of the Hip in a Biomechanical Cadaveric Model.

The gluteus minimus (GMin) and gluteus medius (GMed) are important dynamic stabilizers of the hip, but quantitative data on their biomechanical roles in stabilizing the hip are currently lacking. To (1) establish a reproducible biomechanical cadaveric model of the hip abductor complex and (2) characterize the effects of loading the GMin and GMed on extraneous femoral rotation and distraction. Controlled laboratory study. A total of 10 hemipelvises were tested in 4 muscle loading states: (1) unloaded, (2) the GMin loaded, (3) the GMed loaded, and (4) both the GMin and GMed loaded. Muscle loads were applied via cables, pulleys, and weights attached to the tendons to replicate the anatomic lines of action. Specimens were tested under internal rotation; external rotation; and axial traction forces at 0°, 15°, 30°, 60°, and 90° of hip flexion. When loaded together, the GMin and GMed reduced internal rotation motion at all hip flexion angles (P < .05) except 60° and reduced external rotation motion at all hip flexion angles (P < .05) except 0°. Likewise, when both the GMin and GMed were loaded, femoral distraction was decreased at all angles of hip flexion (P < .05). The results of this study demonstrated that the GMin and GMed provide stability against rotational torques and distractive forces and that the amount of contribution depends on the degree of hip flexion. Improved understanding of the roles of the GMin and GMed in preventing rotational and distractive instability of the hip will better guide treatment of hip pathologies and optimize nonoperative and operative therapies.

Anatomic Popliteus Tendon and Tibiofibular Joint Reconstructions

Background: The popliteus tendon is a primary stabilizer of external knee rotation and has been described as the “fifth ligament of the knee.” Injuries involving the posterolateral corner of the knee commonly involve the popliteus tendon; isolated injury to the popliteus tendon is relatively rare and usually involves a rotatory injury mechanism and symptoms of instability and pain. In this patient, there was a concomitant injury to the proximal tibiofibular joint. Indications: Popliteus tendon reconstruction is indicated for patients with abnormal external rotation on examination and symptoms of pain and instability. Proximal tibiofibular joint reconstruction is indicated for patients with instability of the tibiofibular joint. Technique Description: Preoperative examination under anesthesia is essential to determine the extent of external rotation and assess for additional posterolateral pathology. The popliteus tendon procedure begins with a meticulous common peroneal nerve neurolysis to minimize nerve irritation and decrease the risk of a postoperative foot drop. Semitendinosus and gracilis graft harvest is performed with at least 16 cm of graft length followed by tunnel reaming of the popliteus tendon femoral attachment and tibia tunnel identification and reaming. The femoral attachment of the popliteus tendon is secured, and the semitendinosus graft is anatomically oriented along the native path and passed from posterior to anterior through the femoral tunnel. The gracilis graft for anatomic proximal tibiofibular joint reconstruction requires an anterior to posterior tunnel through the fibular head. Finally, both grafts are secured in the tibial tunnel with the application of an anterior traction force. Results: A cadaveric study by LaPrade et al reported that an anatomic popliteus tendon reconstruction with a semitendinosus autograft significantly reduced external rotation laxity compared with the sectioned state. In addition, popliteus tendon reconstruction resulted in significantly decreased varus laxity, anterior tibial translation, and internal rotation. Discussion: This is a technique that effectively restores external rotation knee stability utilizing an anatomically oriented reconstruction of the popliteus tendon and tibiofibular joint. The popliteus tendon serves as a primary stabilizer to external rotation and facilitates static function of the knee. The proximal tibiofibular joint reconstruction restores the function of the posterior proximal tibiofibular joint ligaments. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Reducing Operation Emissions and Improving Work Efficiency Using a Pure Electric Wheel Drive Tractor

In response to the problems of excessive greenhouse-gas and particulate emissions and the low traction efficiency of conventional diesel tractors in the field, a purely electric wheel-side drive tractor was studied, including an electric motor drive system, a battery ballast system, and an electro–hydraulic suspension system. This paper develops a dynamics model of an electric tractor-ploughing unit under complex soil conditions, leading to the proposal of an active control method for drive wheel torque and a joint control method for the traction force of the suspension system and the front- and rear-axle loads of a tractor. Finally, the tractor is prototyped and assembled, and ploughing tests are carried out. The ploughing results show that the active torque-distribution control method proposed in this study reduces the tractor slip by 14.83% and increases the traction efficiency by 10.28% compared with the average torque-distribution mode. Compared with the conventional traction control mode, the joint control method for traction and ballast proposed in this paper results in a 3.7% increase in traction efficiency, a 15.05% decrease in slip, and a 4.9% reduction in total drive motor energy consumption. This study will help to improve the operation quality and traction efficiency of electric tractors in complex soil conditions.

Adaptive-SMO-Based Traction Force Fluctuation Suppression Strategy Considering Suspension System for High-Speed Maglev Train

The excitation pole of the long stator linear synchronous motor (LSLSM) used to drive the high-speed maglev train is also used as the suspension electro-magnet, which makes the adjustment of the suspension system affect the excitation flux linkage of the motor when the train is running at high speed, resulting in significant non-periodic traction force fluctuations. This paper proposes a traction force fluctuation suppression strategy based on the flux linkage observation. First, based on the mathematical model of the LSLSM in double feed (DF) mode, the voltage equation based on the new extended back-EMF (NEEMF) is derived, which is less sensitive to the changes of parameters, load current, and speed, so that the flux linkage can be estimated more accurately. Then, to meet the high dynamic requirements of flux linkage observation at high speed, a sliding mode flux linkage observer (SMFO) is designed and a design method of the adaptive sliding mode gain is proposed to achieve fast convergence of the system. Finally, the stator reference current required to suppress the traction force fluctuation is calculated. Hardware-in-the-loop (HIL) expe-riments verify the effectiveness of the strategy.

Optimization of the Transmission Ratio by Fuel Consumption

Introduction. The issues of ensuring optimal fuel consumption modes are the subject of constant research in the field of vehicle operation. Works in the field of reducing fuel consumption in most cases are devoted to the study of the design of power units, transmission or aerodynamic features of the body of cars. At the same time, the issues of determining the optimal laws of control of unsteady movement from the point of view of the synthesis of algorithms for controlling the movement of a car have not been considered. To optimize the transmission ratio of cars with unsteady movement, the authors of the work carried out analytical calculations to simplify the synthesis of motion control algorithms, which in turn allowed reducing fuel consumption. The aim of the work was to determine the optimal transmission ratio, which allowed solving the problem of synthesizing vehicle control to reduce fuel consumption.Materials and Methods. The synthesis of algorithms for controlling the movement of a car considered in the work was based on the application of the needle variation of L.S. Pontryagin to invariant features of the real movement. An analytical method was used to estimate energy efficiency of vehicle performance, which was based on determination of optimal transmission ratio of motor vehicles taking into account minimum fuel consumption. The presented method took into account the amount of torque transmitted from the engine crankshaft to the transmission elements, which, depending on the engine power, was realized in the form of traction force on the wheels of the car.Results. The law of optimal change in the transmission gear ratio during acceleration of the car in a minimum time was built. The problem of determining the optimal transmission ratio of the vehicle in the case of driving the vehicle at a constant speed and constant fuel supply and in the case of accelerating the vehicle to a given speed at a constant fuel supply, when the condition ε = const was met, was solved. The result of the considered case of applying the optimal law of change in the transmission gear ratio was the minimization of fuel consumption under restrictions on acceleration (traction force) and speed of the car.Discussion and Conclusion. The use by the authors of the analytical method for determining the transmission ratio of a car, as well as the use of this method in practical calculations for a car with given characteristics, showed the possibility of solving the problem of synthesizing vehicle control using a mathematical apparatus. This was confirmed by the built graphical dependence based on the results of the calculations. The considered cases of movement made it possible to determine the analytical dependencies of the optimal transmission ratio and the speed of the car. The initial data obtained by analytical relationships are applicable for cars with a mixed control mode.

Determining conditions for providing maximum traction efficiency of tractor as part of a soil tillage unit

This study aims to investigate the operation of a tractor as part of the tillage unit on the basis of analysis of its interaction with the supporting surface and the correlation between the mass of the tractor and tool. The classic approach to determining the efficiency factor does not take into account the extensive system of power take-off shafts and the extent of their use in combined tillage units. To solve the related problem, a mathematical apparatus was built in the study, which makes it possible to determine the rational ratio between the traction force of a tractor and the mass of the tillage unit. Underlying the methodological basis of the work is the generalization and analysis of the study of traction indicators of the tractor as part of the tillage unit. Empirical models of unit operation were constructed by employing the basic principles of the system approach and analysis of technical systems. When improving the methodology of research using the method of partial accelerations and our devised procedures, it was possible to significantly reduce the time without compromising the quality of results. The maximum traction efficiency for John Deere 8R series tractors as part of the tillage unit was determined, ηTmax=0.719, as well as the conditions for its provision. The traction efficiency for tractors with wheel formula 4K2, mass Gim=6–10 t, with power consumption from 60 % to 80 % was determined; it is 0.58–0.64. The results of the study make it possible to obtain a new solution to the scientific problem of ensuring the maximum traction efficiency of the tractor as part of the tillage unit, based on the rational ratio between the traction force of the tractor and the weight of the machine-tractor unit. The proposed system approach could be used to justify the layout of units and recommendations regarding their modes of operation in the case of instability of operating mass and traction force

Lamellar macular hole in highly myopic eyes and insights into its development, evolution, and treatment: a mini-review.

Lamellar macular holes (LMHs) are a manifestation of myopic tractional maculopathy (MTM). Owing to the complex and multidirectional traction force in the elongated eyeball, the clinical features, development, evolution, and treatment algorithms of LMH in highly myopic eyes may differ from those of idiopathic LMH or MTM in general. This review aimed to specifically explore the LMHs in highly myopic eyes. Several developmental processes of LMH and their association with macular retinoschisis have been demonstrated, with the tractional component identified in all processes. Epiretinal proliferation was more prevalent and more extensive in LMHs in highly myopic eyes than in idiopathic LMHs. LMHs in highly myopic eyes may remain stable or progress to foveal detachment and full-thickness macular hole with or without retinal detachment. The predictive factors associated with disease progression were summarized to facilitate monitoring and guide surgical intervention. The treatment of LMHs in highly myopic eyes was based on an algorithm for treating myopic tractional maculopathy, including gas tamponade, pars plana vitrectomy, macular buckling, and a combination of vitrectomy and macular buckling. New internal limiting membrane (ILM) manipulation techniques such as fovea-sparing ILM peeling or fovea-sparing ILM peeling combined with ILM flap insertion could reduce the risk of developing iatrogenic full-thickness macular holes postoperatively. Further research should focus on the treatment of LMH in highly myopic eyes.

Quantitative characterization of tumor cell traction force on extracellular matrix by hydrogel microsphere stress sensor.

Cell traction force (CTF) is a kind of active force that is a cell senses external environment and actively applies to the contact matrix which is currently a representative stress in cell-extracellular matrix (ECM) interaction. Studying the distribution and variation of CTF during cell-ECM interaction help to explain the impact of physical factors on cell behaviors from the perspective of mechanobiology. However, most of the strategies of characterizing CTF are still limited by the measurement needs in three-dimensional (3D), quantitative characteristics and in vivo condition. Microsphere stress sensor (MSS) as a new type of technology is capable of realizing the quantitative characterization of CTF in 3D and in vivo. Herein, we employed microfluidic platform to design and fabricate MSS which possesses adjustable fluorescent performances, physical properties, and size ranges for better applicable to different cells (3T3, A549). Focusing on the common tumor cells behaviors (adhesion, spreading, and migration) in the process of metastasis, we chose SH-SY5Y as the representative research object in this work. We calculated CTF with the profile and distribution to demonstrate that the normal and shear stress can determined different cell behaviors. Additionally, CTF can also regulate cell adhesion, spreading, and migration in different cell states. Based on this method, the quantitative characterization of CFT of health and disease cells can be achieved, which further help to study and explore the potential mechanism of cell-ECM interaction.

High Dynamic Range Probing of Single-Molecule Mechanical Force Transitions at Cell-Matrix Adhesion Bonds by a Plasmonic Tension Nanosensor.

Mechanical signals in animal tissues are complex and rapidly changed, and how the force transduction emerges from the single-cell adhesion bonds remains unclear. DNA-based molecular tension sensors (MTS), albeit successful in cellular force probing, were restricted by their detection range and temporal resolution. Here, we introduced a plasmonic tension nanosensor (PTNS) to make straight progress toward these shortcomings. Contrary to the fluorescence-based MTS that only has specific force response thresholds, PTNS enabled the continuous and reversible force measurement from 1.1 to 48 pN with millisecond temporal resolution. We used the PTNS to visualize the high dynamic range single-molecule force transitions at cell-matrix adhesions during adhesion formation and migration. Time-resolved force traces revealed that the lifetime and duration of stepwise force transitions of molecular clutches are strongly modulated by the traction force through filamentous actin. The force probing technique is sensitive, fast, and robust and constitutes a potential tool for single-molecule and single-cell biophysics.

Metamodeling on uncertainty quantification in the behavior of the tire/road interaction of vehicles

In recent years, the automotive industry has been developing applied research to meet customer’s needs; considering safety, vehicle comfort and energetic efficiency. In particular, automotive tires have a prominent position in this research area, ensuring good vehicle handling, comfort and safety. In the vehicle dynamics performance, excellent gripping and reduced rolling resistance in the tires are crucial to maximize the energetic efficiency in a reliable way. However, to ensure such a level of reliability in vehicle operation, the inherent uncertainties of tires, as well as other factors subject to variability must be taken into account in the vehicle design. In this way, the present paper analyzes in detail the effect of variations in some parameters such as ambient temperature, ground conditions, vertical load, speed and tire inflation on the analysis of vehicle dynamics. A Metamodeling approach associated with the Monte Carlo Simulation was employed to develop the mathematical models to analyze the effect of uncertain parameters on the tire rolling resistance; traction, centripetal and lateral forces, using experimental data from the literature, in the longitudinal and lateral vehicle dynamics. Therefore, the present research brings as an innovation an integrated approach to the input parameters of the system with the rolling resistance through the developed metamodels. There was a substantial variability of up to 15% both up and down in the Maximum Traction Force of a vehicle in response to variations in the vehicle’s weight and the coefficient of tire rolling resistance. In contrast, the Lateral Force exhibited a greater variability, with a 25 downward and 10% upward variation associated with the weight and friction coefficient variability of the vehicle. Further investigations into the sensitivity analysis highlight the significant influence of the friction coefficient and temperature on the Traction Forces of the vehicle.

The improvement and retention of skills in shoulder dystocia management with the use of high-fidelity simulation: The SAFE (SimulAtion high-FidElity) study

BackgroundShoulder dystocia is a relatively uncommon but serious childbirth-related emergency. AimTo explore the improvement and retention of skills in shoulder dystocia management through high-fidelity simulation training. MethodsThe SAFE (SimulAtion high-FidElity) study was a prospective cohort study that utilised a high-fidelity birth simulator. Registered midwives and final year midwifery students were invited to participate in a one-day workshop at 6-monthly intervals. There was a 30-minute initial assessment, a 30-minute theoretical and hands-on training, and a 30-minute post-training assessment on shoulder dystocia management. Pre-training and post-training values for the predetermined outcomes were compared. In each workshop we assessed the proportion of successful simulated births, the performance of manoeuvres to manage shoulder dystocia, the head-to-body birth time, the fetal head traction force, the quality of communication, the perception of time-to-birth, and the self-reported confidence levels. FindingsThe baseline workshop recruited 101 participants that demonstrated a significant increase in the proportion of successful simulated births (8.9% vs 93.1%), and a two-fold to three-fold increase in the score of manoeuvres, communication, and confidence after training. Those with low pre-training levels of competency and confidence improved the most post-training at baseline. There was a retention of manoeuvres, communication skills and confidence at 6 months. There was no reduction in fetal head traction force over time. Those being proficient before initial training retained and performed best at the 6-month follow-up. ConclusionThe SAFE study found a significant improvement in skills and confidence after the initial high-fidelity simulation training that were retained after 6 months.

Удосконалення методики визначення нормативів тягових властивостей автомобіля skoda fabia при стендовому діагностуванні

As you know, the main output parameters characterizing the state of the power unit are the power and torque values. These parameters determine the dynamic qualities of the car, and can also affect fuel consumption and the level of harmful emissions.&#x0D; The above parameters are checked using traction roller stands. Such stands allow you to reproduce real speed and load modes. Usually, the traction force on the drive wheels is measured on the stands. It is then easy to calculate the power at a given test speed. Traction force is determined, on the one hand, by the output torque of the engine, on the other hand, by mechanical losses in the transmission. In turn, the moment is determined by the perfection of the combustion process, the complete use of the energy of combustion products, and mechanical losses in the engine itself.&#x0D; When there is no reliable, experimentally obtained external speed characteristic of an internal combustion engine, Leiderman's formula is usually used for its approximate construction.&#x0D; This technique gives a satisfactory approximation of the dependence of power on revolutions. However, the moment curve is noticeably different from the experimental one. due to the fact that it uses only one experimental point - the maximum power and the corresponding revolutions. Therefore, a refined method of building the external speed characteristic using the example of the SKODA FABIA car is proposed using additional equations that specify the values of the empirical coefficients A, B, C.&#x0D; On the basis of the refined external speed characteristics of the engine, the revolutions of the crankshaft are converted into speed, and a graph of the permissible traction force against the speed is drawn according to the derived formula. Standards for diagnostic parameters of the power unit in acceleration mode under partial load are also defined.&#x0D; The proposed method of registering engine diagnostic parameters to determine their normative values provides an individual approach to diagnosing the technical condition of cars.

A modified motor-clutch model reveals that neuronal growth cones respond faster to soft substrates.

Neuronal growth cones sense a variety of cues including chemical and mechanical ones to establish functional connections during nervous system development. Substrate-cytoskeletal coupling is an established model for adhesion-mediated growth cone advance; however, the detailed molecular and biophysical mechanisms underlying the mechanosensing and mechanotransduction process remain unclear. Here, we adapted a motor-clutch model to better understand the changes in clutch and cytoskeletal dynamics, traction forces, and substrate deformation when a growth cone interacts with adhesive substrates of different stiffnesses. Model parameters were optimized using experimental data from Aplysia growth cones probed with force-calibrated glass microneedles. We included a reinforcement mechanism at both motor and clutch level. Furthermore, we added a threshold for retrograde F-actin flow that indicates when the growth cone is strongly coupled to the substrate. Our modeling results are in strong agreement with experimental data with respect to the substrate deformation and the latency time after which substrate-cytoskeletal coupling is strong enough for the growth cone to advance. Our simulations show that it takes the shortest time to achieve strong coupling when substrate stiffness was low at 4 pN/nm. Taken together, these results suggest that Aplysia growth cones respond faster and more efficiently to soft than stiff substrates.

Теоретичні засади використання триланкових автопоїздів для виконанні перевезень вантажів

Today, in the EU countries, three-link road trains of various layout schemes are used for freight transportation, in particular semi-trailer, trailer on a rolling cart and «B-Dauble» type, which helps increase the efficiency of the transportation process. The total weight of such road trains is the same and is at the level of 60 tons, and the length is up to 26 m. The satisfactory maneuverability of a three-link road train is expressed in the ability to fit it into all the turns found on the traffic routes and to maneuver (make turns and, if necessary, move reversing) at the loading and unloading points. Therefore, the comparative evaluation of the considered three-link road trains was carried out according to maneuverability.&#x0D; Among the existing maneuverability indicators for road trains, the overall traffic lane (GSR) and the ability to move in reverse are the most important. The trajectories of the links of the road train, which determine the GSR, are obtained by solving the differential equations of motion for the road train of the «B-Double» type with all controlled axles, on the basis of which all other layout schemes are considered, during the circular motion of the road train. At the same time, it was established that only a three-link «B-double» type road train with a three-axle non-steerable first semi-trailer and a steerable second semi-trailer with a drive on its rear axle meets the requirements of Directive 2002/7/EC regarding maneuverability. Therefore, among the considered road trains, this type of road train may become promising. It has been established that the stable movement of the road train in reverse without assembling the links can be achieved by transferring the traction force to the rear steered axle of the semi-trailer. The necessary power of the engine installed on the rear axle of the semi-trailer was determined, provided the road train moves along a curved path, which was 65 kW. In the case of using the power method of turning the wheels of the rear axle of the semi-trailer, such engines must be located on each of the wheels. The necessary torque difference on the wheels of the axle of the semi-trailer, which corresponds to the angle of rotation of its steered wheels, is determined, under the condition of movement when moving along a curve of a given radius. Thus, at a fixed turning speed of v = 2 m/s when moving along curves of a small radius, the difference in torques on the axle of the semi-trailer should vary within 370–1050 Nm, which are provided by the adopted motor-wheels.

Discrete network models of endothelial cells and their interactions with the substrate

Endothelial cell monolayers line the inner surfaces of blood and lymphatic vessels. They are continuously exposed to different mechanical loads, which may trigger mechanobiological signals and hence play a role in both physiological and pathological processes. Computer-based mechanical models of cells contribute to a better understanding of the relation between cell-scale loads and cues and the mechanical state of the hosting tissue. However, the confluency of the endothelial monolayer complicates these approaches since the intercellular cross-talk needs to be accounted for in addition to the cytoskeletal mechanics of the individual cells themselves. As a consequence, the computational approach must be able to efficiently model a large number of cells and their interaction. Here, we simulate cytoskeletal mechanics by means of molecular dynamics software, generally suitable to deal with large, locally interacting systems. Methods were developed to generate models of single cells and large monolayers with hundreds of cells. The single-cell model was considered for a comparison with experimental data. To this end, we simulated cell interactions with a continuous, deformable substrate, and computationally replicated multistep traction force microscopy experiments on endothelial cells. The results indicate that cell discrete network models are able to capture relevant features of the mechanical behaviour and are thus well-suited to investigate the mechanics of the large cytoskeletal network of individual cells and cell monolayers.

Adaptive robust control with slipping parameters estimation based on intelligent learning for wheeled mobile robot

The widespread use of wheeled mobile robots (WMRs) in many fields has created new challenges. A critical issue is wheel slip, which, if not accurately determined and controlled, causes instability and deviation from the robot’s path. In this paper, an intelligent approach for estimating the longitudinal and lateral slip of wheels is proposed that can effectively compensate for the negative effects of slippage. The proposed algorithm relies on three regression networks to estimate the longitudinal slip ratio of the right and left wheels and sideslip angle on terrains with different friction coefficients. The datasets collected during tests on different surfaces with various maneuvers are used to train the artificial neural networks (ANNs). A developed dynamic model of a WMR considering wheel slip and modified traction force is presented. The adaptive robust controller, based on sliding mode control (SMC), is introduced to deal with the problems related to slipping, unknown uncertainties, and disturbances. The simulation results demonstrate that the presented controller has better performance than SMC in handling external disturbances and uncertainties, which leads to reduction in tracking error and faster convergence to zero. The proposed controller with an intelligent slip estimator, has been applied to a four-wheel mobile robot to demonstrate its effectiveness and feasibility. The high accuracy of slip estimation in the mentioned intelligent algorithm has resulted in the presented method being on average 26% more effective in reducing the tracking error than the control method without slip compensation in each test for circular trajectory.

Математическая модель для проектирования линейных асинхронных электродвигателей и ее программная реализация

Mathematical models are the main tool for the layout design of linear asynchronous electric motors. Existing design models of linear asynchronous electric motors assume that the device is powered from a source of multiphase symmetrical positive sequence current, which excludes from consideration the asymmetry of the inductor phase currents and the associated reduction in traction force. This approach is not flexible enough, since the operation of linear asynchronous electric motors in a wide range of movement speeds assumes a functional relationship between the current asymmetry coefficient and the movement speed. The study developed a mathematical model for design purposes that implements the functional relationship between the current asymmetry coefficient and the speed of movement. The mathematical model represents 13 linear equations linking geometric dimensions, current loads, electromagnetic field characteristics and mechanical forces with the speed of the secondary element of the electric motor. The current load of an electric motor has a variable degree of ellipticity depending on the speed of movement. An algorithmic study of the mathematical model was carried out and corresponding software modeling tools were developed. The proposed program algorithm, containing two subroutines, is implemented using the Maple symbolic computing software package. In order to expand the range of users, the software model is additionally implemented in C++. In this case, the functional dependence of the asymmetry coefficient of the exciting current wave on the speed of movement is implemented in the form of an iterative procedure for the case of connecting the winding of the linear asynchronous electric motors inductor to a source of symmetrical three-phase voltage according to the “triangle” circuit. Using the example of a three-phase linear asynchronous electric motors, the electromagnetic and mechanical characteristics of the electric motor were simulated. It was stated that the influence of current asymmetry on the mechanical characteristics of the linear asynchronous electric motors is small and is expressed in the region of high speeds. This makes it possible, in design tasks for the layout of an electric motor, to use models that involve powering the linear asynchronous electric motors from a symmetrical current source or to introduce a fixed asymmetry coefficient into them.

Determination of the Performance Characteristics of a Traction Battery in an Electric Vehicle

Electric vehicles are the most innovative and promising area of the automotive industry. The efficiency of a traction battery is an important factor in the performance of an electric vehicle. This paper presents a mathematical model of an electric truck, including modules for the traction battery to determine the depth of battery discharge during the operation of the electric truck, a traction electric system for the electric truck and a system for calculating traction forces on the shaft in electric motors. As a result of the modelling, the charging and discharging currents of an accumulator battery in a real cycle of movement in peak and nominal modes of operation in electric motors and at different voltages of the accumulator battery are determined. A functional scheme of a generalized model of the electric vehicle traction electrical equipment system is developed. An experimental battery charge degree, torques of asynchronous electric motors, temperature of electric motors and inverters, battery voltage and the speed of electric motors have been measured and analysed. The developed complex mathematical model of an electric vehicle including a traction battery, two inverters and two asynchronous electric motors integrated into an electric portal bridge allowed us to obtain and study the load parameters of the battery in real driving cycles. Data were verified by comparing simulation results with the data obtained during driving.