Wheel Radius Research Articles

Running performance analysis of a passenger coach with small-radius wheels in the diverging route of a turnout

Small-radius wheels are gradually introduced on special rail vehicles, such as double-decker coaches and piggyback wagons. It allows for a low-floor design and further increases the loading capacity of vehicles. From the perspective of vehicle dynamics, small-radius wheels have lower unsprung mass than the nominal wheels with a radius of 460 mm, and it could mitigate the wheel-rail dynamic interaction. Also, the contact patch size is reduced due to the increased curvature of the rolling contact circle, and they are more sensitive to changes in the track geometry than nominal wheels, especially in turnouts with discontinuous rail profiles. To investigate the dynamic response of small-radius wheels in a turnout, the Manchester Benchmark passenger coach with variable radius wheels and a left-hand turnout with a radius of 245 m are introduced in this work. The influence of wheel radii on the running performance, including the wheel-rail interaction and wheel damage behaviour, is investigated by numerical simulations. In addition, a sensitivity study is executed to evaluate the influence of unsprung mass and wheel flange friction on the performance of a vehicle whose wheel radius is 275 mm, and the potential remedy to mitigate high wheel wear is proposed.

Justification of the dibber drill machines wheel parameters under the condition of rotation uniformity

The article presents theoretical and experimental study results of rotation uniformity for seed drill wheel and possibilities of using wheeled dibber drills in the design of sowing machines. The main purpose of research is to obtain mathematical models of wheel dynamic model expressing the dependence of wheel sliding on the technological and design factors. The objectives were to determine rolling coefficients in order to use their numerical characteristics in the analysis of wheel dynamic model and in particularity, the axial load, wheel radius, parameters of the dibber drills wheel and speed of movement. Freely rotating wheels with a rim width of 170 mm and diameters of 524 mm and 712 mm were used in the experiments. Soil in the channel was brought close by properties to the soil prepared for sowing. Measurement of the driving force was made by strain gauge equipment at a wheel speed of 0.47 m/s. The optimal axial load at the masses of 35-55 kg and diameter in the range of 500-800 mm of thewheeled dibber drills was determined. It was proved, that wheel slip within 10-12% will assure the quality of sowing crops technological process execution at speeds up to 3 ms-1. Numerical values of wheel sliding coefficients are on average 58% lower for rolled soil than for loose soil for equal conditions.

Optimum Design of Stair-Climbing Robots Using Taguchi Method

Environmental issues like pollution are major threats to human health. Many systems are developed to reduce pollution. In this paper, an optimal mobile robot design to reduce pollution in Green supply chain management system. Green supply chain management involves as similating environmentally and economically feasible solutions into the supply chain life-cycle. Smartness, advanced technologies, and advanced networks are becoming pillars of a sustainable supply chain management system. At the same time, there is much change happening in the logistics industry. They are moving towards a new logistics model. In the new model, robotic logistics has a vital role. The reasons for this change are the rapid growth of the e-commerce business and the shortage of workers. The advantages of using robotic logistics are reduction in human errors, faster delivery speed, better customer satisfaction, more safety for workers, and high workforce adaptability. A robot with rocker-bogie suspension is a six-wheeled mobile platform that has a distinctive potential to keep all wheels on the ground continuously. It has been designed to traverse rough and uneven terrain by distributing the load over its wheels equally. However, there is a limitation to achieving high-speed mobility against vertical barriers. In this research, an optimal design of product delivery wheeled robots for a sustainable supply chain system is proposed to ensure higher adaptability and maximum stability during climbing staircases. The design parameters of the proposed robot are optimized using Taguchi Method. The aim is to get a smooth trajectory of the robot’s center-of-mass. The proposed approach realizes a robot with much-improved stability which can climb over heights more than the size of the wheel (i.e., 3 times the radius of wheels). The results reveal that the modified rocker-bogie system not only increases the stair-climbing capability but also thwarts instability due to overturning of a wheel of the robot.

ПОВЫШЕНИЕ ОПОРНЫХ СВОЙСТВ МНОГООПОРНОЙ МАШИНЫ «КУБАНЬ-ЛК1»

Considered Issues of increasing the reliability of the movement of the sprinkling machine (SM) on the example of "Kuban-LK1" were considered. Significant rutting leading to loss of patency due to increased rain intensity at the end of the SM (last bogies and cantilever) was noted, which ultimately leads to a decrease in machine performance. To eliminate this drawback, pneumatic tires with a profile width of 21.3 - 24 are installed on the outermost SM bogie, the rain intensity of which is 1.0 mm / min, and the length is 350 - 400 m, instead of serial tires 18.4 - 24. To eliminate this shortcoming, pneumatic tires with a profile width of 21.3 - 24 are installed on the extreme SM trolley, the rain intensity of which is 1.0 mm / min, and the length is 350 - 400 m, instead of serial tires 18.4 - 24. Modifications of SM with a length of 500 meters or more characterize increased intensity (ρ = 1.0-1.2 mm/min), and, accordingly, an increased value of surface water runoff, while the bearing capacity of the soil in the area of the last spans is up to 70 kPa. This determines the need to install wide-profile pneumatic tires with a profile width of 21.3 - 24 not on one, but on several last bogies. However, based on the high cost and weight indicators of pneumatic tires 21.3 - 24, according to theoretical and experimental studies, the authors recommend equipping the last SM bogies with pneumatic tires of a conventional profile 18.3 - 24 with a rigid flare, the radius of which is determined by reducing the wheel radius by an amount equal to the average depth of immersion of tires of a conventional profile, at the end of the irrigation season. The conducted experimental studies have shown that the installation of an expander on the pneumatic tires of the last bogies provided the indicators of the reference rutting ability, equivalent to those of the intermediate bogies.

Robot Path Estimation from Odometry Measurements: Loop Closure Based on Autocorrelation

The problem of estimating the Robot path when covering closed trajectories using only the wheels odometry information is met in indoor low-cost robotic applications. Random and systematic errors related to the measured angle accuracy, deviations from the desired path and wheel radius in robot turns, introduced significant errors in the process of estimating the actual path. In this paper the autocorrelation function is used for accurate estimation of the path periodicity and to reconstruct the robot path. Real-life experiments using a real robot showed minor differences between the estimated and the predicted path.

Efficient System Identification of a Two-Wheeled Robot (TWR) Using Feed-Forward Neural Networks

System identification of a Two-Wheeled Robot (TWR) through nonlinear dynamics is carried out in this paper using a data-driven approach. An Artificial Neural Network (ANN) is used as a kinematic estimator for predicting the TWR’s degree of movement in the directions of x and y and the angle of rotation Ψ along the z-axis by giving a set of input vectors in terms of linear velocity ‘V’ (i.e., generated through the angular velocity ‘ω’ of a DC motor). The DC motor rotates the TWR’s wheels that have a wheel radius of ‘r’. Training datasets are achieved via simulating nonlinear kinematics of the TWR in a MATLAB Simulink environment by varying the linear scale sets of ‘V’ and ‘(r ± ∆r)’. Perturbation of the TWR’s wheel radius at ∆r = 10% is introduced to cater to the robustness of the TWR wheel kinematics. A trained ANN accurately modeled the kinematics of the TWR. The performance indicators are regression analysis and mean square value, whose achieved values met the targeted values of 1 and 0.01, respectively.

Design of an Air Suction Wheel-Hole Single Seed Drill for a Wheat Plot Dibbler

Focusing on the problems of the poor filling ability and stability of the mechanical wheat seeder and the complicated structure of the pneumatic seeder, a special air suction wheel-hole single seed drill for remote controlled self-propelled single seed dibbler in wheat plots was designed in this paper. According to the agronomic requirements of precision seeding in wheat plots, the seeding wheel radius was set at 180 mm 16 suction holes. Using the discrete element simulation software EDEM to analyze the seed disturbance effect of different parameter designs, the thickness of seed suction ring was 16 mm, the height of seed suction mouth was 4.5 mm, and the diameter of seed suction cam was 12 mm. Through hydrodynamic simulation, the phase angle of the negative pressure chamber was 280 degrees, positive pressure chamber was 22 degrees, phase angle of the unpressurized interval zone was 20 degrees, thickness of the negative pressure chamber was 24.5 mm, diameter of transition pipe was 17.5 mm and length of the transition pipe was 14.5 mm. Based on the above design parameters, the samples were then processed and benchtop experiments carried out. The results showed that under the best operating parameters, the re-suction index was 0.82%, the leakage index was 6.67%, and the qualified index was 92.41%, which met the design requirements. This study could provide a reference for the design of single-seed dibbling technology in wheat plots.

Considerations for Achieving Equivalence between Hub- and Roller-Type Dynamometers for Vehicle Exhaust Emissions

Emissions from vehicles can be measured on the road or in laboratories using dynamometers that simulate the forces that a vehicle is subject to while driving on the road. In the light-duty vehicle regulations, only roller-type dynamometers are allowed. For hub-type dynamometers, due to the direct connection of the dynamometers to the wheel hubs, additional parameters that are used are rotational mass, dynamic wheel radius, and the tire force–slip relationship. Following up on an experimental study which showed that equivalent emission results can be achieved between roller- and hub-type dynamometers, this work presents and evaluates methods to determine parameters used by a hub-type dynamometer for mimicking roller-type dynamometer behavior. It also discusses methods to determine the parameters to simulate specific road conditions or when using only a hub-type dynamometer. The results show that using a constant dynamic radius for each wheel and a linear tire force–slip relationship is sufficient for emission measurement because typical errors in these parameters are practically negligible. A typical error in rotational mass results in a minor error in the determined forces during coast down, but the typical accuracy of this parameter is in parity with the difference allowed in the regulation. The final conclusion is that using the information already stated in the certificate of conformity (CoC) of the vehicle (for the coast down), and reasonably set parameters for wheel dynamic radius and the tire slip–force relationship, hub-type dynamometers should yield equivalent results to roller-type dynamometers.

Autonomous Bikebot Control for Crossing Obstacles With Assistive Leg Impulsive Actuation

As a single-track mobile platform, bikebot (i.e., bicycle-based robot) has attractive capability to navigate through narrow, off-road terrain with high speed. However, running crossing step-like obstacles creates challenges for intrinsically unstable, underactuated bikebots. This article presents a novel autonomous bikebot control with two assistive legs to navigate crossing obstacles. The proposed design integrates the external/internal convertible form-based motion control with leg-assisted impulse actuation. The leg–terrain interaction generates impulsive torques to help maintain navigation and balance when running across obstacles. The control performance is analyzed and guaranteed. The experimental results confirm that under the control design, the bikebot can smoothly run crossing multiple step-like obstacles with heights more than one-third of the wheel radius. The comparison results demonstrate the superior performance than those under only the velocity and steering control without leg assistive actuation.

Critical delay as a measure for the difficulty of frontal plane balancing on rolling balance board

The relation between balancing performance on rolling balance board and reaction time is investigated. Ten young healthy adults performed balancing trials on a rolling balance board with different wheel radius R and stance widths d in the frontal plane. A 2- and a 3-degree-of-freedom models subject to delayed state feedback with a single lumped reaction delay were created in order to describe hip and hip–lumbar strategies. The critical delays of the underlying models, for which state feedback stabilization is still possible, were determined. This critical delay is a good measure of the difficulty of the balancing task: the smaller the critical delay, the more difficult the balancing task. Subjects’ response time to visual stimuli correlates with the critical delay of the models, therefore, it can be used as an indirect indicator for balancing skill. Hip–lumbar strategy was found to be superior to pure hip strategy in the sense that it allows larger reaction delay. Overall, rolling balance board is a simple and convenient tool to assess human’s balancing skill. The difficulty of the task can be tuned by employing different wheel radius with different stance widths while it can be measured by a single number: the critical delay of the underlying model. Improvement in balancing skill therefore can easily be monitored during balance therapy and physical rehabilitation.

Experimental Comparison of Hub- and Roller-Type Chassis Dynamometers for Vehicle Exhaust Emissions

The emissions of vehicles are measured in laboratories with roller-type chassis dynamometers, which simulate road driving resistances. Hub-coupled dynamometers, which are not included in the regulations for emission measurements, are commonly used for research and development purposes, for example, to assess powertrain capabilities, simulate on-road trips, and calibrate the control of individual wheels. As they do not need particular infrastructure and offer a wider range of applications, they could be a more economical alternative, especially if they could also be used for emission measurements for the type approval of vehicles. Nevertheless, the two types have not been directly compared in the literature, and, thus, their equivalency, especially regarding emission measurements, is not known. In this study, the emissions of a diesel and a gasoline plug-in vehicle were compared using the same analytical equipment and by switching only the roller and hub dynamometers. The diesel vehicle was further tested on a second roller-type dynamometer with the same driver and a second driver. The results of the two dynamometer types were very close, even though the repeatability of the measurements was very narrow. The main message of this work is that hub-type dynamometers can be used interchangeably with roller-type dynamometers. The points that need to be addressed, such as the determination of dynamic wheel radius and tire slip level, are also discussed.

The results of analysis of traction dynamics and stability of planetary rover’s motion for determination of special wheel chassis’ boundary design parameters

The analysis of the influence of the design parameters of the rover chassis on the traction dynamics, as well as the static and dynamic stability is presented. The analysis was carried out on the basis of the design parameters of the following rovers: Lunokhod-1, LRV, Sojourner, Spirit and Opportunity, as well as Curiosity. The results of the analysis of the influence of the radius and width of the rover wheel on the specific thrust coefficient are presented. An approach has been formed for determining the permissible displacement of the center of gravity of the rover in the longitudinal direction, which provides static stability. The choice of the formula for determining the maximum permissible speed of movement of automatic research planetary rovers has been substantiated. A number of recommendations have been drawn up for working out the design of the rover at the early stages of design. Boundary values of the rover wheel width, depending on the wheel radius, are proposed. The influence of the load on a separate wheeled propulsion unit on the specific thrust coefficient has been determined.

Simulation Analysis and Experimental Study of Piezoelectric Power Generation Device Based on Shape Memory Alloy Drive.

In order to solve the problem of waste heat collection from energy consumption, a thermal energy generation device combining shape memory alloy and piezoelectric materials has been designed. The shape memory alloy is heated and deformed to drive the drive wheel continuously, and the impact wheel is deformed against the piezoelectric cantilever beam during the rotation of the drive wheel to generate electricity. In this paper, the impact force generated by the impact wheel and the output voltage of the piezoelectric cantilever beam during the rotation process are given. Finally, the experimental test shows that the larger the radius of the drive wheel, the lower the impact force of the wheel and the lower the output voltage of the piezoelectric cantilever beam; the larger the diameter of the shape memory alloy wire, the higher the impact force of the wheel and the higher the output voltage of the piezoelectric cantilever beam; the more teeth of the drive wheel, the higher the impact frequency of the piezoelectric cantilever beam and the higher the output voltage. The maximum output voltage of the thermoelectric converter is 14.2 V, when the drive wheel radius is 13 mm, the shape memory alloy wire diameter is 1 mm and the number of impact wheel teeth is 6. The new structural design provides a new structural model for waste heat recovery and thermal energy generation technology. The new structural design provides a new approach and idea for waste heat recovery and thermal energy generation technology.

Wheel fault diagnosis model based on multichannel attention and supervised contrastive learning

As wheels are important components of train operation, diagnosing and predicting wheel faults are essential to ensure the reliability of rail transit. Currently, the existing studies always separately deal with two main types of wheel faults, namely wheel radius difference and wheel flat, even though they are both reflected by wheel radius changes. Moreover, traditional diagnostic methods, such as mechanical methods or a combination of data analysis methods, have limited abilities to efficiently extract data features. Deep learning models have become useful tools to automatically learn features from raw vibration signals. However, research on improving the feature-learning capabilities of models under noise interference to yield higher wheel diagnostic accuracies has not yet been conducted. In this paper, a unified training framework with the same model architecture and loss function is established for two homologous wheel faults. After selecting deep residual networks (ResNets) as the backbone network to build the model, we add the squeeze and excitation (SE) module based on a multichannel attention mechanism to the backbone network to learn the global relationships among feature channels. Then the influence of noise interference features is reduced while the extraction of useful information features is enhanced, leading to the improved feature-learning ability of ResNet. To further obtain effective feature representation using the model, we introduce supervised contrastive loss (SCL) on the basis of ResNet + SE to enlarge the feature distances of different fault classes through a comparison between positive and negative examples under label supervision to obtain a better class differentiation and higher diagnostic accuracy. We also complete a regression task to predict the fault degrees of wheel radius difference and wheel flat without changing the network architecture. The extensive experimental results show that the proposed model has a high accuracy in diagnosing and predicting two types of wheel faults.

Kinematics and dynamics of an incomplete circular wheel drive of an agricultural tractor

The disadvantage of wheeled tractors is soil compaction, slipping due to limited traction, low tangential force. Experimental studies of a tractor with incomplete circular wheel mover on stubble, sand and virgin snow showed an increase in cross-country ability, a decrease in skidding, an increase in traction, and an increase in productivity. The purpose of the study is to develop a methodology for kinematic and dynamic analysis of incompletely rounded wheel propellers with a built-in differential. The equation of motion of the wheel is obtained on the basis of two-stage overcoming by the wheel of a single threshold obstacle taking into account the longitudinal and radial stiffness of the tire, its deformation, air resistance in the tire. The main influence is provided by translational speed, wheel radius and radial stiffness, the moment of inertia of the wheel and the shoulder of the application of mass. Planetary gearbox proposed in which the shaft of the driving satellite is a bearing, while the radius of the gear is an order of magnitude smaller than the radius of the wheel. The direction of improvement of wheel mover, increasing their traction properties is justified.

Exploration of polar crane geometric parameters with the use of modern geodetic electronic gauges

The paper presents recent explorations of polar crane parameters with the use of the latest geodetic electronic gauges, instead of conventional devices recommended by normative documents for measuring instruments. A set of basic geometric conditions for polar cranes was specified with required precision, namely: convergence of diagonals at the specified points, inside rolling radius of the wheels, lateral sliding of the wheels, longitudinal sliding of the wheels, position of wheels at a given radius, position of wheels at a given diameter, rolling radius of virtual wheels in small balancers, transverse slippage of bridge virtual wheels in small balancers. All basic parameters are shown not to surpass theoretical (design) parameters. The findings illustrate that the main operational characteristics of the polar crane explored herewith are permissible.

Scene wheels: Measuring perception and memory of real-world scenes with a continuous stimulus space

Abstract Precisely characterizing mental representations of visual experiences requires careful control of experimental stimuli. Recent work leveraging such stimulus control has led to important insights; however, these findings are constrained to simple visual properties like colour and line orientation. There remains a critical methodological barrier to characterizing perceptual and mnemonic representations of realistic visual experiences. Here, we introduce a novel method to systematically control visual properties of natural scene stimuli. Using generative adversarial networks (GAN), a state-of-art deep learning technique for creating highly realistic synthetic images, we generated scene wheels in which continuously changing visual properties smoothly transition between meaningful realistic scenes. To validate the efficacy of scene wheels, we conducted two behavioral experiments that assess perceptual and mnemonic representations attained from the scene wheels. In the perceptual validation experiment, we tested whether the continuous transition of scene images along the wheel is reflected in human perceptual similarity judgment. The perceived similarity of the scene images correspondingly decreased as distances between the images increase on the wheel. In the memory experiment, participants reconstructed to-be-remembered scenes from the scene wheels. Reconstruction errors for these scenes resemble error distributions observed in prior studies using simple stimulus properties. Importantly, perceptual similarity judgment and memory precision varied systematically with scene wheel radius. These findings suggest our novel approach offers a window into the mental representations of naturalistic visual experiences.

On-machine precision truing of ultrathin arc-shaped diamond wheels for grinding aspherical microstructure arrays

Precision grinding with ultrathin arc-shaped diamond (UAD) grinding wheels provides a satisfactory solution for the fabrication of high-quality microstructures on tungsten carbide (WC) molds. However, ultrathin grinding wheels are difficult to be trued, due to the limited small grinding wheel profile. In this paper, an on-machine truing method for ultrathin arc-shaped diamond grinding wheels is proposed. First, a model of the three-axis linkage controlling truing for the diamond grinding wheel was introduced. Then, the effects of the setting and measurement errors of the grinding wheel on the profile radius were theoretically analyzed. A mathematical model of the error was developed. Furthermore, an aspherical microstructure array of tungsten carbide was ground by the trued diamond grinding wheel. The experimental results demonstrated that the expected arc radius of the grinding wheel could be achieved and the binderless tungsten carbide mold could be ground efficiently and precisely. The profile error of the grinding wheel (diameter of 23 mm, thickness of 0.38 mm) reached 8.5 μm. An aspherical microstructure array surface of tungsten carbide with a form accuracy of 15 μm was obtained by grinding with the trued diamond grinding wheel without additional compensation.

An investigation on the effective performance area of the electric bicycle with variable key input parameters

In this paper, we will present the effect of a key input parameter on the motion dynamics, electricity consumption, and timing required for velocity and battery voltage to reach stable status. From the results, the researcher can optimize the effective performance area through analysis of the motor torque, velocity, moving distance, and battery voltage. To achieve this goal, a simulation model was established through MATLAB Simulink software to investigate motion and electricity consumption characteristics. Besides that, to support research results an experiment was conducted on the real road test. The research found that the EB mass increases from 21 kg to 43 kg, electric consumption increased by 0.53%, time to reach stable voltage increased from 14.93 to 18.53 s, and time to reach stable velocity increased from 23.3 to 24.53 s. When the transmission ratio increased from 2.18 to 3.43, electricity consumption increased by 0.54%, and time to reach stable voltage decreased from 17.3 to 14.9 s, and time to reach stable velocity decreased from 16.13 to 13.73 s. Following decrease in the EB's wheel radius from 0.42 m to 0.3 m, electricity consumption decreased by 0.13%, time to reach stable voltage increased from 16.1 to 18.5 s, time to reach stable velocity decreased from 17.5 to 16.1 s. When the frontal area increased from 0.423 m2 to 1.623 m2, electricity consumption increased by 0.14%, and the time to reach stable voltage decreased from 17.3 to 14.9 s, time to reach stable velocity decreased from 14.9 to 12.5 s. When the slope ratio increased from 0% to 0.82%, electricity consumption increased by 0.08%, time to reach stable voltage increased from 18.5 to 19.7 s, and time to reach stable velocity increased from 14.9 to 16.1 s.

Scene wheels: Measuring perception and memory of real-world scenes with a continuous stimulus space.

Precisely characterizing mental representations of visual experiences requires careful control of experimental stimuli. Recent work leveraging such stimulus control has led to important insights; however, these findings are constrained to simple visual properties like color and line orientation. There remains a critical methodological barrier to characterizing perceptual and mnemonic representations of realistic visual experiences. Here, we introduce a novel method to systematically control visual properties of natural scene stimuli. Using generative adversarial networks (GANs), a state-of-the-art deep learning technique for creating highly realistic synthetic images, we generated scene wheels in which continuously changing visual properties smoothly transition between meaningful realistic scenes. To validate the efficacy of scene wheels, we conducted two behavioral experiments that assess perceptual and mnemonic representations attained from the scene wheels. In the perceptual validation experiment, we tested whether the continuous transition of scene images along the wheel is reflected in human perceptual similarity judgment. The perceived similarity of the scene images correspondingly decreased as distances between the images increase on the wheel. In the memory experiment, participants reconstructed to-be-remembered scenes from the scene wheels. Reconstruction errors for these scenes resemble error distributions observed in prior studies using simple stimulus properties. Importantly, perceptual similarity judgment and memory precision varied systematically with scene wheel radius. These findings suggest our novel approach offers a window into the mental representations of naturalistic visual experiences.