Large Wheel Research Articles

A Study on Wheel Sinkage and Rolling Resistance with variations in wheel geometry for Plain and Lugged wheels on TRI -1 Soil Simulant

Wheel-soil Interaction studies are gaining momentum in the field of Terramechanics, but the basis is Terzaghi’s bearing capacity equation. For the current study, on a lunar soil simulant TRI – 1, two plain rigid wheels are considered, i.e., small wheel (dia. of 210 mm and width of 50 mm) and large wheel (dia. 160 mm and width 32 mm). Also, different number of lugs (N = 8, 12, 16) with various lug heights (h = 5 mm, 10 mm, 15 mm) are used. In this paper, the variation of wheel sinkages from experiments obtained for various wheel weights are examined and presented. The parameter, Coefficient of rolling resistance (CRR) is determined for various cases. Hence, rolling resistance was determined and examined from the obtained CRR for all cases. Among the cases examined, the large wheel with weight 67.44 N for plain wheels and weight 67.85 N for lugged wheel (no. of lugs = 16, and height of lugs = 5 mm) registered better mobility. Similarly, for small wheel with weight 52.189 N for plain wheel and weight 52.481 N for lugged wheel (no. of lugs = 16, and height of lugs = 5 mm) registered better mobility, a lesser rolling resistance for these cases.

A novel Lap-MRF method for large aperture mirrors

A novel magnetorheological finishing (MRF) method, which is named Lap-MRF, is proposed in this paper. The magnetorheological fluid (MR fluid) in the polishing zones can be renewed continuously so that the determinacy is ensured. A lap, instead of a large polishing wheel, is used to expand the polishing area, which improves the material removal rate largely. Lap-MRF uses flexible MR fluid as polishing pad to match the surface well. Moreover, the polishing pad executes planetary motion so as to obtain smooth surface. In this paper, the principle of Lap-MRF and the theoretical model of material removal rate are presented. Using the finite element analysis method, the permanent magnet unit is simulated and a multi-parameter optimization is conducted to improve the performance of Lap-MRF. Finally, a series of polishing experiments and simulation process are carried out. For K9 sample, the volume removal rate is up to 0.76 mm3/min and its relative change rate is less than 5.5%. For silicon modification layer sample, the surface roughness is improved to 0.788 nm RMS (root mean square) from 1.610 nm RMS. There is no deep pit and the polishing ripple is not apparent on the surface. For Φ1000 mm flat mirror, the convergence efficiency of simulation process is up to 97.2%. These results verify the validity of the proposed method, which makes Lap-MRF to be a promising finishing technology for large aperture mirrors.

TECHNOLOGY OF REPAIR AND RESTORATION OF LARGE-MODULAR GOLDEN GEAR WHEELS BY HIGH-SPEED WOOD PROCESSING

The subject of the research in the article are topical issues related to the development of technology for the repair and restoration of large-sized gears of drives of walking excavators, ore-grinding mills, ball mills. The goal is to develop a new technology for repairing and repairing large-sized gears with a module (m = 12-65 mm). The task is to obtain a guaranteed quality of restoration of gear rims after repair with high-performance machining of large wheels operating in an aggressive abrasive environment. The method of intermittent rolling with the use of disk non-modular cutters is proposed (the dimensions of the mill do not depend on the module of the treated teeth), equipped with ceramic plates and special milling calipers. The method of intermittent rolling is used on gear-grinding and gear grinding machines and has the advantage that at the time of the working stroke of the tool the workpiece is either stationary or makes a slight turn, i.e. The treatment proceeds in comparison with the running-in method, under more stringent conditions. Results of implementation. Two new directions were adopted for the implementation of the new high-speed dental processing technology. The first was the development of simple special milling calipers mounted on the chamfering machines of MAAG (Switzerland). The second accounted for the extremely small number of factories that had MAAG machines, and therefore envisaged the development, manufacture and introduction of special milling calipers to widely used vertically hobbing machines. The introduction of a new technology for repairing and rebuilding toothed wheels during the finishing of hardened wheels with the use of a gear-cutting machine was carried out in production conditions when machining the wheels of a pseudo-planetary gearbox with the following characteristics: m = 28 mm; ; ; ; b = 400; ; steel 34ХМЮАА; HRC 48 ... 54. In comparison with the process of gear grinding, in which tensile stresses are created in the surface layer of the part, the blade treatment is most favorable. Compressive stresses increase wear resistance of parts, contractual and flexural strength of gears. Conclusions. The industrial introduction of new technology of blade machining of repair and restored large-sized gear wheels makes it possible to reduce the labor intensity of a finishing operation 3-4 times, and also eliminates the need to purchase expensive and low-performance gear grinding machines for import. In this case, the surface quality of the teeth is higher than in the case of gear grinding, because Excludes defects such as burns, microcracks.

On the overriding issue of train front end collision in rail vehicle dynamics

ABSTRACTA three-dimensional dynamic model of crashed vehicles coupled with moving tracks is developed to research the dynamic behaviour of the train front end collision on tangent tracks. The three-dimensional dynamic model consists of a crashed vehicle model, moving track models, a simple wheel–rail contact model, a velocity-based coupler model and the model of energy absorption and anti-climbing devices. The vector method dealing with the nonlinear wheel–rail geometry is put forward in the paper. The developed model is applicable in the scope that central collisions occur on tangent tracks at low speeds. The examples of the vehicle impacting with a rigid wall and the train front end collision are carried out to obtain the dynamic responses of vehicles. The overriding issue is studied on the basis of the wheel rise in train collisions. The results show that the second bogie of the first colliding vehicle possesses the maximal wheel rise. The wheel rise increases with the increase of vehicles. However, the number of vehicles has tiny influence on the overriding in train collisions at low speeds. On the contrary, the impact speed has significant influence on the overriding in train collisions. The wheel rise increases rapidly if the impact speed is close to the critical speed of overriding. The large wheel rise is principally generated by the great coupler force related to the rigid impact in the axial direction.

Invocations of the Driver Assists

Invocations of the Driver Assists

Reply to Giannakos, K. Comment on: Toughness of Railroad Concrete Crossties with Holes and Web Openings. Infrastructures 2017, 2, 3

This paper responds to the discussion [1] by Dr. K. Giannakos over our technical note [2].[...]

Numerical Design and Analysis of the Tractive Performance of Large Off-road Wheels Driving on Dry Sands by DEM

Aimed at the typical condition of large off-road wheels operating on dry sands, in which the sand apparently gets discontinuous and rutted by lugged wheels with larger load, the numerical test for tractive performance is designed and analyzed by discrete element method. It is indicated from the analysis that: Off-road wheels equipped with paralleled lugs show the superiorly tractive performance, especially in aspects of adhesion and tractive force, while V-shaped lugs come second. Types of lugs have little relationship with the sinkage and the efficiency coefficients, which closely reach the maximum in range of 20%-30% of slip. Nonetheless, lugged wheels’ performance universally precedes a smooth one’s.

Innovation to Improve Competitiveness of SMES of Leather Bags Combined with Batik and Tenun in Malang City

Some problems faced by micro-small-medium enterprises (SMEs) of leather bags combined with batik and tenun (Indonesian weave) in Malang become the concern of this paper. In producing products, some enterprises still use simple technology. The products, therefore, have low quality which influences their competitiveness in market. In addition, there is no finance access to bank to increase their business scale. In order to solve the problems and give total solution, technology and capital aids are offered to the enterprises. As well as intermediate technology which is in the form of roll press machine and sewing assembling machine with a large wheel provided to make the products neater and stronger, training on simple business transaction recording is applied to prevent a problem regarding finance access to bank. Keywords : Innovation, Competitiveness of SMEs, Intermediate Technology

An approach on wheel position and orientation calculation for helical broaching tool sharpening

Helical chip gullets play a crucial role in the performance of broaching tool. Well-sharpened helical rake flanks, which require accuracy of rake angle, smoothness of rake flank, and the safety of operators, are significantly to maintain its broaching performance. In this study, a wheel orientation and position calculating approach was developed to the resharpen of helical rake flank by a ring-like grind wheel. With modeling the process requirements of helical rake flank sharpening as the constraints like single side contacting and desired rotation direction of grinding wheel, the enveloping theory-based contact curve identification helped the wheel orientation calculation approximate to a nonlinear searching problem for easily addressing by Newton-Raphson method. Then, the analyses of contact curves with different wheel orientations and a ground helical rake flank proofed the sharpening process requirement was satisfied, and the examined results of rake angle for both ground rake flank and simulated bars verified the accuracy of the presented approach. At last, optimal grinding wheel setup that has taken larger wheel size and practicable orientation was suggested based on the relationship analysis among wheel radiuses and orientations.

Use of Rubber Mats to Improve the Deformation and Degradation Behavior of Rail Ballast under Cyclic Loading

AbstractThe deterioration of a rail track due to large dynamic wheel loads is inevitable over the years and leads to frequent, high-cost maintenance. This problem is more critical in isolated rail ...

Tyre modelling for an autonomous articulated wheel loader conducting a V-shape loading cycle simulation

Virtual product developments (VPDs) tools have a great effect on reducing the cost of development, which explains the considerable amount of attention they received lately from researchers. In this work, two different VPD tyre models, restricted fully non-linear and enhanced non-linear transient models, are tested through modelling and simulation. A detailed multibody mechanical system model of a large wheel loader conducting a V-shape loading cycle was used to test the performance differences between the two transient tyre models. VPD simulations show that both tyre models enable the operator (controller) to drive the machine tracking the desired path; however, the enhanced non-linear tyre model shows larger deviation and less operator comfort when compared with the restricted non-linear transient tyre model. Results also show the ability of the restricted tyre model to produce higher forces and moment to keep the machine on track.

Tyre modelling for an autonomous articulated wheel loader conducting a V-shape loading cycle simulation

Virtual product developments (VPDs) tools have a great effect on reducing the cost of development, which explains the considerable amount of attention they received lately from researchers. In this work, two different VPD tyre models, restricted fully non-linear and enhanced non-linear transient models, are tested through modelling and simulation. A detailed multibody mechanical system model of a large wheel loader conducting a V-shape loading cycle was used to test the performance differences between the two transient tyre models. VPD simulations show that both tyre models enable the operator (controller) to drive the machine tracking the desired path; however, the enhanced non-linear tyre model shows larger deviation and less operator comfort when compared with the restricted non-linear transient tyre model. Results also show the ability of the restricted tyre model to produce higher forces and moment to keep the machine on track.

Study on Drive System of Hybrid Tree Harvester.

Hybrid tree harvester with a 60 kW diesel engine combined with a battery pile could be a “green” forest harvesting and transportation system. With the new design, the diesel engine maintains a constant engine speed, keeping fuel consumption low while charging the batteries that drive the forwarder. As an additional energy saving method, the electric motors work as generators to charge the battery pile when the vehicle moves downhill. The vehicle is equipped with six large wheels providing high clearance over uneven terrain while reducing ground pressure. Each wheel is driven via a hub gear by its own alternating current motor, and each of the three wheel pairs can be steered independently. The combination of the diesel engine and six electric motors provides plenty of power for heavy lifting and pulling. The main component parameters of the drive system are calculated and optimized with a set of dynamics and simulated with AVL Cruise software. The results provide practical insights for the fuel tree harvester and are helpful to reduce the structure and size of the tree harvester. Advantage Environment provides information about existing and future products designed to reduce environmental impacts.

Experimental and simulation studies on a novel gravity based passive tracking system for a linear solar concentrating collector

A novel gravity based passive solar tracking mechanism; suitable to a linear solar concentrating collector has been conceptualized, developed, simulated, analyzed and tested experimentally. Attempt has been made to minimize the tracking load and error by controlling in dripping rate or filling rate of liquid in the gravity system. The identified key influencing design parameters in the proposed mechanism are sprocket wheel radius, spring stiffness and tracking radius. Large sprocket wheel, low stiff spring and small tracking radius minimizes the tracking loads. The recommended sprocket wheel radius and tracking wheel radius are 125 mm and 60 mm respectively. The simulation studies are validated with the experimental results. Practically obtained collector’s incidence angle is compared with the minimum required (theoretical) incidence and found a satisfactory match. The improvement in thermal efficiency of the collector with the proposed tracking mechanism has been highlighted by comparing the efficiency of intermittent tracking collector.

Gyro-based odometry associated with steering characteristics for wheeled mobile robot in rough terrain

Mobile robot used for planetary exploration performs several scientific missions over long distance travel and needs to have a high degree of autonomous mobility system because the communication delay from the Earth impedes its direct teleoperation. Localization of a mobile robot is of particular importance on the autonomous mobility. Classical localization methods such as wheel/visual odometry have been widely investigated and demonstrated, but they possess a well-known trade-off between computational cost and localization accuracy. This paper proposes an accurate gyro-based odometry method for a wheeled mobile robot in rough terrain. The robot in rough terrain is often subject to large wheel slip or vehicle sideslip related with its steering maneuver, and those slips degrade the localization accuracy. The basic approach of the proposed method is to exploit odometry data for the robot distance traveled as well as gyroscope data for the robot heading calculation; however each data-set is weighted in accordance with steering characteristics of a robot in rough terrain. The usefulness of the proposed method is examined through field experiments using a wheeled mobile robot testbed in Martian analog site. The experimental result confirms that the proposed method accurately estimates the robot trajectory.

능동 합성개구레이더위성의 다섯 개 반작용휠 운용방법

위성의 자세제어 및 기동을 위해서는 네 개의 반작용휠을 피라미드 형태로 배치하여 사용하는 것이 일반적이다. 하지만 위성의 관성모멘트가 크거나 사용할 수 있는 반작용휠의 용량이 작은 경우에는 다섯 개의 반작용휠을 사용하는 것을 생각해볼 수 있다. 이 경우, 반작용휠 배치부터 운용방법까지 여러 가지 문제를 다시 고려해야 한다. 능동합성개구레이더 위성은 관측 각도 변화를 위해서 롤축 방향으로 빠른 기동이 요구된다. 본 논문에서는 합성개구레이더 위성의 롤축 방향 기동성능 향상을 위하여 다섯 개의 반작용휠을 배치하는 경우, 이를 운용하는 방법을 연구해본다. For satellite attitude control and maneuver, normally four reaction wheels are used through pyramid configuration. However, if satellite's moment of inertia is large or available reaction wheels' capability is small, we can consider using five reaction wheels. In this case, we should think the arrangement of wheels and their operation method. Active SAR satellite requires high agile maneuver about roll axis to achieve looking angle change. In this research, we study the operation method of five reaction wheels configuration for fast roll maneuver.

Merlin’s ‘invalid or gouty chair’ and the origin of the self-propelled wheelchair

Wheelchairs are a major advance in enabling independence for people with walking difficulties. The first self-propelled wheelchair has been attributed to John Joseph Merlin, the 'ingenious mechanick', in the early 19th century and his 'gouty chair' is exhibited at Kenwood House. Research would suggest that comparable chairs existed in France as early as 1751 and the French Revolutionary, Georges Couthon, used one to get around Paris. A later design, also attributed to Merlin, the invalid wheelchair, features large wheels with outer hoops for the occupant to grasp and this is the true ancestor of the modern wheelchair.

Concept of Inflatable Outer Wheel Rover for Exploration of Lunar and Planetary Holes and Subsurface Caverns

Three huge vertical holes have been found on the Moon and their scientific explorations are planned by the UZUME (Unprecedented Zipangu (Japan) Underworld of the Moon Exploration) Project. For such explorations, a rover with large wheels is preferred for climbing over bumps. However, the exhaust materials from landers or rovers should be avoided to prevent contamination of the terrain. This paper proposes a rover with inflatable tubes that function as outer wheels. A prototype with one degree of freedom was built. The inflatable wheel was 1000 mm in diameter and 400 mm in width, and weighed 2.0 kg. A small cart, which was used as a weight, was moved on the torus to revolute the rover. Each cart weighed 0.5 kg. The performance of the rover was tested and compared with the calculated results. The climbable step height and slope angle were statistically calculated and were independent of gravity. The climbable step height and slope angle were 15 mm and 9°, and they almost agreed with the calculated results.

Comparison of the inertial properties and forces required to initiate movement for three gait trainers

ABSTRACTThe purpose of this study was to evaluate the inertial properties and forces required to initiate movement on two different surfaces in a sample of three commonly prescribed gait trainers. Tests were conducted in a laboratory setting to compare the Prime Engineering KidWalk, Rifton Pacer, and Snug Seat Mustang with and without a weighted anthropometric test dummy configured to the weight and proportions of a 4-year-old child. The Pacer was the lightest and the KidWalk the heaviest while footprints of the three gait trainers were similar. Weight was borne fairly evenly on the four casters of the Pacer and Mustang while 85% of the weight was borne on the large wheels of the mid-wheel drive KidWalk. These differences in frame style, wheel, and caster style and overall mass impact inertial properties and forces required to initiate movement. Test results suggest that initiation forces on tile were equivalent for the Pacer and KidWalk while the Mustang had the highest initiation force. Initiation forces on carpet were lowest for the KidWalk and highest for the Mustang. This initial study of inertia and movement initiation forces may provide added information for clinicians to consider when selecting a gait trainer for their clients.

Investigation on cornering brake stability of a heavy-duty vehicle based on a nonlinear three-directional coupled model

A nonlinear three-directional coupled lumped parameters (TCLP) model is proposed for a heavy-duty vehicle to investigate the longitudinal, lateral and vertical dynamics of vehicles simultaneously. The nonlinear property of suspension damping is described by a fitted exponent model from experimental data. The nonlinear tire forces in different directions are modeled by the nonlinear Gim model and the vertical single dot contact model with square nonlinearity. The system responses are calculated by numerical integration and compared with the Functional Virtual Prototyping (FVP) model and the test data, so as to verify the validity of this new vehicle model. With Lateral-Load Transfer Ratio (LTR) and yaw rate as evaluation indexes, the influences of system parameters on cornering brake stability are analyzed. The critical vehicle speed table is also obtained. The study shows that high vehicle running speed, large front wheel steering angle, large tire cornering stiffness or small braking moment is harmful to yaw stability and roll stability. Road surface frictional coefficient mainly influences yaw stability, and vertical tire stiffness and road surface roughness mainly influence roll stability.