Wheel Track Research Articles

Triangular state stress and deformation analysis of deformable tracked wheel

The Variable Morphology Wheel-Track Mechanism (VMWTM) is an innovative mobile platform design designed to overcome the limitations of traditional track and wheel designs in different terrains and mission requirements. Based on the importance of the crawler wheel in the tracked vehicle, the vehicle transmission shaft transmits the power and torque of the power source to the crawler chassis, so the overall working performance of the vehicle depends to a certain extent on the performance of the crawler wheel. In-depth and detailed research on the structure of the track wheel module is an important issue in the current vehicle design and manufacturing work. Based on the relevant theories and technologies of the finite element method, this paper conducts in-depth analysis and design. Taking the whole crawler wheel mechanism and the key components as the analysis object, the basic research method is the finite element method. The working principle of the crawler wheel is analyzed, and the load calculation, stress characteristics and structural strength of the key components of the triangular crawler wheel module are deeply explored according to the technical requirements and actual working conditions.

High-silicon spring steel transformation to carbide-free bainitic (CFB) steel: a mechanical and tribological approach under rolling/sliding conditions

The present study concentrates on the development of carbide-free bainite steel and explores its tribological and mechanical characteristics using a newly devised disk-on-disk tribometer. The microstructure of the treated samples was examined through heat treatment at various holding temperatures (300, 350, and 400 °C) and durations (10, 20, and 30 min), along with isothermal transformation. The wear rate demonstrated significant sensitivity to holding duration, transformation temperature, phase fraction, and the stability of retained austenite. The microstructural analysis encompassed atomic force microscopy (AFM), FE-SEM, x-ray diffraction (XRD), and energy-dispersive x-ray spectroscopy (EDS). The study extensively investigated the robust correlation among mechanical properties, microstructure, wear behavior, and the presence of retained austenite (RA) and bainite volume fraction. The findings indicate that carbide-free bainite steel holds promise for replacing conventional railway wheel track steel in the steel industry. The structural property correlations have developed of high silicon steel, hardness reduced with increasing temperature and isothermal preserving time; resulting in a gradual increase in the wear rate of CFB steel. The salt bath soaking temperature of 350 °C with a period of 30 min was found to be the preeminent wear properties condition for CBF steel.

Enhancement of Microwave Heating Technology for Emulsified Asphalt Mixtures Using SiC-Fe3O4 Composite Material.

The application of microwave heating technology can significantly enhance the water evaporation rate of emulsified asphalt mixtures post paving. To improve the microwave absorption and curing performance of these mixtures, SiC-Fe3O4 composite material (SF) was incorporated. This addition aims to enhance the microwave absorption efficiency and accelerate the curing process of emulsified asphalt mixtures under microwave heating. This study begins with an analysis of the microwave absorption principles pertinent to emulsified asphalt mixtures. Subsequently, the microwave heating temperature fields of ordinary emulsified asphalt mixture (EAM), SiC emulsified asphalt mixture (S-EAM), Fe3O4 emulsified asphalt mixture (F-EAM), and SiC-Fe3O4 emulsified asphalt mixture (SF-EAM) were simulated using COMSOL Multiphysics finite element software (COMSOL 6.2). The early strength variations in SF-EAM under different microwave heating durations were then examined through adhesion tests, leading to the proposal of a microwave heat curing process for SF-EAM. Finally, the wear resistance, water damage resistance, rutting resistance, and skid resistance of SF-EAM post-microwave curing were evaluated through wet wheel wear tests, wheel track deformation tests, and road friction coefficient tests. The results indicate that the optimal microwave heating time is 90 s, with the microwave absorption performance of the materials ranked as follows: EAM, S-EAM, F-EAM, and SF-EAM, from lowest to highest. The road performance of SF-EAM complies with specification requirements, and its wear resistance, water damage resistance, and rutting resistance are notably improved after microwave heating.

Effect of High Polymer, Crumb Rubber, and Epoxy-Modified Asphalt Binders on Laboratory Performance of Open-Graded Friction Course Mixtures

Open-graded friction course (OGFC) is a thin asphalt mixture surface layer. It is gap-graded with a high percentage of coarse aggregates that are nearly uniform in size, resulting in a high percentage of interconnected air voids and asphalt binder, which provides improved skid resistance, visibility, and decreased pavement–tire noise. However, construction personnel at the Louisiana Department of Transportation and Development reported that conventional OGFC mixtures have durability issues and shorter service life, compared with thin asphalt mixture lifts. Hence, effects of different asphalt binder types on the performance of OGFC mixtures were evaluated. Five types of asphalt binder were utilized: conventional styrene-butadiene-styrene (SBS) asphalt binder PG 76-22M; high SBS content asphalt binder PG 88-28; diluted epoxy asphalt (EA) binder with two different dosages (25% and 50%); and a hybrid modified asphalt binder prepared with SBS and crumb rubber modifier PG 76-22G. The optimal aggregate structures were determined based on minimum required air voids and voids in coarse aggregate. Physical and mechanical tests were conducted to assess the performance of OGFC mixtures, including draindown, permeability, loaded wheel track, and Cantabro abrasion loss. Results indicate that OGFC mixtures incorporating diluted EA binder exhibited lower draindown values than mixtures containing PG 76-22M and PG 88-28. Moreover, mixtures with PG 88-28 and 50% EA binders demonstrated improved resistance to rutting. Mixtures with 50% EA and PG 88-28 binders demonstrated improved durability, compared with mixtures with PG 76-22M for unaged and aged conditioning, as measured by Cantabro abrasion loss values.

Integrated Control of a Wheel–Track Hybrid Vehicle Based on Adaptive Model Predictive Control

Integrated Control of a Wheel–Track Hybrid Vehicle Based on Adaptive Model Predictive Control

Enhancement of porous asphalt mixtures modified with various fibers and ethylene–vinyl acetate polymer

Porous asphalt mixture is conventional hot mix asphalt (HMA) with substantially decreased fines, which produces an open-graded mixture that enables the water to flow through an interconnected void space. Porous asphalt is a permeable system that has a lot of benefits. However, because of its open structure, the durability of this mixture decreases, and both its stability and resilient modulus are much lower compared to the dense conventional asphalt mixtures. Also, the high void percentage may lead to an increase in the draindown proportion. Fibers (cellulose or mineral) and polymer-modified binders are recommended for porous asphalt mixtures, especially in hot and moderate climates. The objective of this study is to improve the porous asphalt mixture's performance by using ethylene–vinyl acetate (EVA) polymer-modified bitumen. Two types of fibers (cellulose fibers and glass wool fibers) were used, separately to determine the control mixture. Four different proportions of EVA polymer were added to the bitumen (1%, 2%, 3%, and 4%) and Scanning Electron Microscopy (SEM) was used for better investigating of the bitumen microstructure, then The Marshall mix design was used to determine the optimum EVA content (OEC) for the porous asphalt mixture. Several performance tests were conducted to investigate the characteristics of the porous asphalt mixture, such as the infiltration rate, binder draindown, the wheel track and the cantabro abrasion tests. The findings of the study conclude that the addition of EVA polymer to the porous asphalt mixtures enhances the performance as it increases stability by 20.8% and the infiltration rate by 20.6%. It decreases binder draindown proportion by 33.3%, cantabro abrasion loss by 25.1% and the rut depth at 5,000 cycles and 10,000 cycles by 29.8% and 19.7%, respectively.

Research on the strain gauge mounting scheme of track wheel force measurement system based on high-speed wheel/rail relationship test rig

PurposeThis paper aims to analyze the stress and strain distribution on the track wheel web surface and study the optimal strain gauge location for force measurement system of the track wheel.Design/methodology/approachFinite element method was employed to analyze the stress and strain distribution on the track wheel web surface under varying wheel-rail forces. Locations with minimal coupling interference between vertical and lateral forces were identified as suitable for strain gauge installation.FindingsThe results show that due to the track wheel web’s unique curved shape and wheel-rail force loading mechanism, both tensile and compressive states exit on the surface of the web. When vertical force is applied, Mises stress and strain are relatively high near the inner radius of 710 mm and the outer radius of 1110 mm of the web. Under lateral force, high Mises stress and strain are observed near the radius of 670 mm on the inner and outer sides of the web. As the wheel-rail force application point shifts laterally toward the outer side, the Mises stress and strain near the inner radius of 710 mm of the web gradually decrease under vertical force while gradually increasing near the outer radius of 1110 mm of the web. Under lateral force, the Mises stress and strain on the surface of the web remain relatively unchanged regardless of the wheel-rail force application point. Based on the analysis of stress and strain on the surface of the web under different wheel-rail forces, the inner radius of 870 mm is recommended as the optimal mounting location of strain gauges for measuring vertical force, while the inner radius of 1143 mm is suitable for measuring lateral force.Originality/valueThe research findings provide valuable insights for determining optimal strain gauge locations and designing an effective track wheel force measurement system.

Traffic induced compaction and physical quality of grassland soil under different soil moisture deficits

Soil compaction is widely recognised as one of the key contributors to soil degradation in Europe. Information is needed for farmers and land managers to guide management decisions and prevent traffic-induced soil compaction. Predicted soil moisture deficit (SMD) from the hybrid SMD model may provide information on when soil conditions are suitable for machinery trafficking. The objective of this study was to investigate the relationship between soil water content and traffic induced soil compaction and if a predicted SMD threshold level could be identified, above which soils can be trafficked without significant soil compaction occurring. The study also evaluated the capacity of selected soil physical indicators such as soil bulk density and water stable aggregates to indicate soil physical degradation across a range of soil water contents. The experiment was carried out on grassland with moderately drained soil, located in Wexford, Ireland. Machinery trafficking of the soil with a tractor equipped with a fully loaded slurry tanker, was assessed in the field across the four seasons of the year. Traffic was imposed at target predicted SMD + 10 mm (relatively dry soil), 0 mm (relatively moist soil), and −10 mm (relatively wet soil). After each traffic event, samples were taken in the middle of the wheel track at three depths (0–10, 10–20 and 20–30 cm) to assess soil bulk density. Water aggregate stability was evaluated at the same three depths following the fourth traffic event. Results showed that when planning field machinery operations, especially repeated trafficking events, soil becomes prone to physical degradation when predicted SMD ≤ 0 mm. Traffic on soil at predicted SMD 0 mm (close to field capacity) lead to compaction after two traffic events. However, when predicted SMD was −10 mm, soil bulk density indicated no significant difference from the non-trafficked soil. When water-stable aggregates were measured on the predicted SMD 0 mm and −10 mm trafficked soils, it indicated physical degradation of soil. Hence, bulk density alone did not give an accurate indication of soil structural quality when soils where trafficked under relatively wet or saturated conditions (SMD −10 mm). These results indicate that avoiding machinery trafficking of grassland soils at predicted SMD ≤ 0 mm will help protect soil physical structure. On soils where multiple machinery operations are likely to occur over the year, trafficking when the predicted SMD > 0 mm is recommended to minimise loss of soil physical quality.

Capacity assessment of railway axle journal bearing addressing a localized rolling contact fatigue failure mechanism

Abstract A framework for assessing the capacity of railway axle journal bearings is presented after elaborating on the locale rolling contact fatigue (RCF) failure mechanism. Three phases are conducted, including the determination of bearing service loads, finite element analysis (FEA) on the localized RCF stresses of bearing components, and the life-related capacity assessment on the bearings and bearing components. Results prove that wheel-track (WT) contact forces inspected by an instrumented wheel set can be transferred into bearing service loads. Two-step FEA from the global wheel set to the local bearings is used to obtain localized RCF stresses at dangerous locations around the bearing contact regions. After determining the locations, a life-related capacity assessment is performed by evaluating equivalent RCF stresses and lives at the locations to determine the weakest bearing component. Typical practice is given in agreement with FEA. This method deals with the FEA of bearing structures, material cyclic stress-strain curves, and probabilistic RCF life curves. Therefore, this work greatly enhances the development of rail-bearing materials, innovative structures, and capacity assessment.

Evaluating the Properties of Improved Asphalt Material and Hot Mixture Asphalt by Adopting Rotational Viscosity Test and Wheel Track Test

Scientists and engineers are continually attempting to enhance the performance of asphalt pavements by altering the asphalt. Because of their natural compatibility with asphalt cement as well as their exceptional properties, polymers may offer an excellent opportunity for asphalt modification to extend service life and reduce early distress by enhancing the properties of hot-mix asphalt. This study aims to explain how the various polymers influence the properties of hot mix asphalt with a wet procedure using asphalt produced locally at the Al-Durah refinery and various polymers. Styrene-butadiene-styrene (SBS), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and (PVC+SBS) are examples of these polymers. Three and five per cent of the polymer are utilized for SBS, PTFE, and PVC, respectively. The asphalt cement ratio for (SBS+PVC) was 2.5% by weight at various blending times. The polymer asphalt mixtures are evaluated using Wheel Track tests and then compared to the conventional mixture. The modification of bitumen with polymers enhanced its conventional properties, such as viscosity. In addition, it was determined that the mechanical properties of HMA prepared with PMB samples, as measured by wheel track experiments, improved with increasing polymer contents.

A Review on the Evaluating the Influence of Employment Nano-Matekaolin and Additive Materials on the Improvement of Hot Mixture Asphalt Properties

In previous years, the world witnessed great urban development which increased interest in this aspect. To keep pace with this development, several things and new materials have been created to raise the standard of road construction. One of these things is the use of nanomaterials. Currently, the use of nanomaterials has become common to improve the asphalt mixtures which are used in the construction of flexible pavement because of the rise in traffic volumes and vehicles loads. This study deals with review of past related studies that improving the properties of asphalt mixtures through the use of nanometakaoline in the hot asphalt mixture in different proportions. Different proportions of nanometakaoline were used for the Hot Mixture Asphalt properties revised in these studies which were shown that the adding of nano-metakaoline led to improve the properties of Hot Mixture Asphalt to resist the traffic load and environmental effects. They used Marshall Test, indirect test, wheel track tests and others tests to exam the properties of improved Hot Mixture Asphalt and compared with the standard mixture (control).

Characterization of two types of modified sulphur pellets for sulphur-extended asphalt mixtures

The application of sulphur to partially replace traditional bituminous binder in asphalt mixture can offer attractive technical, economic and environmental advantages. Globally, Kazakhstan is the seventh largest producer of sulphur as this element is abundantly generated by many petroleum refining industries. This study concisely evaluates the performance of asphalt mixtures added with two types of modified sulphur pellets pivoting on laboratory and field investigations. Wheel track tests indicate a substantial reduction in rutting development for sulphur-extended asphalts (average final value ≈ 2 mm) compared to unmodified ones (average final value ≈ 7 mm). Further, uniaxial tension stress tests evaluating the durability at −20 °C, −30 °C, −40 °C document very similar results between modified and regular mixtures in terms of tensile strength and corresponding failure strain. Eventually, the construction of a pilot road surface stretch laid employing the sulphur-based pellets points at an approximate 5 % economic saving. Such promising experimental outcomes buttress the application suitability of sulphur-extended asphalt mixtures in Kazakhstan and encourage further thorough research in this direction.

Field performance validation of the Louisiana balanced asphalt mix design framework

The balanced mix design (BMD) approach was implemented by agencies to complement the volumetric mix design method. The BMD approach addresses typical pavement distresses using mechanical tests. This study aimed to validate the Hamburg Wheel Track (HWT) rut depth and Semi Circular Bend (SCB) critical strain-energy release rate (Jc) thresholds specified in the Louisiana BMD framework. Seven field projects, including 13 pavement sections with 8–18 service years, were evaluated. Field distress data showed that the maximum HWT rut depth and minimum SCB Jc thresholds are effective parameters for assessing rutting and cracking performance, respectively.

WheTLHLoc 4W: Small‐scale inspection ground mobile robot with two tracks, two rotating legs, and four wheels

AbstractWheTLHLoc 4W is the second version of a hybrid leg–wheel–track small‐scale ground mobile robot, developed for surveillance and inspection applications. It differs from its predecessor, WheTLHLoc 2W, in two main aspects: the number of wheels (four instead of two), and the new leg design. The overall size of the robot varies depending on the configuration: 500 × 420 × 140 mm (length × width × height) in tracked mode with lowered legs, 315 × 420 × 310 mm in tracked mode with raised legs, and 430 × 420 × 260 mm in wheeled mode. The robot is sufficiently small to explore narrow spaces, both indoors and outdoors, switching between wheeled locomotion on compact surfaces and tracked locomotion on irregular and yielding terrain. Due to its small length, the robot can stand on one tread of a stair. Nevertheless, it is capable of climbing stairs, and the step height limit has been augmented from 165 mm to 180 mm (+9.1%) with respect to the first version, keeping constant the robot overall size. This enhancement has been achieved through a mechanical redesign of the two rotating legs: each leg now features a pair of smaller wheels, actuated by the same actuator through a gear train, instead of a single larger wheel. The significant increase in the maximum step height expands the robot's capabilities for indoor environments, as stairs with a rise higher than 180 mm are extremely uncommon. The paper discusses the mechanical design of WheTLHLoc 4W, the trajectory planning for step/stair climbing, and provides an analytical comparison between the novel architecture and the first version in terms of stability against overturn and slippage. These analytical results are then experimentally verified. The findings demonstrate that the new leg design not only increases the maximum step height (+9.1%), but also reduces the minimum friction coefficient required for successful stair climbing (−19.1% for the maximum step).

Model-Based Analysis of the Accuracy of Tracking Control and Energy Efficiency of a Six-Wheeled Skid-Steered Robot

This article concerns the modeling and motion control of a mobile robot with six independently driven and non-steered wheels. The main research issue is analyzing the influence of the structure of the control system and wheel track on the control accuracy and energy efficiency during robot motion on horizontal paved ground. For this purpose, the kinematic relationships for the robot are discussed and a simplified dynamics model for control applications is developed. The robot’s dynamics model takes into account the most important phenomena of the wheel interaction with the paved ground, including slip. In addition, it is supplemented with a model of the robot’s drive units. Two versions of the control system were adopted for analysis, i.e., with the wheels’ controller only and additionally equipped with a pose controller. Simulation studies were carried out for the developed robot dynamics model and the analyzed versions of the control system in order to investigate the influence of the track width of the wheels and the structure of the control system on motion accuracy and energy efficiency. In order to quantitatively compare the results for the analyzed solutions, quality indices were introduced. The results of the simulation research indicate the influence of the track width of the wheels on the accuracy of motion when using the wheels’ controller, as well as its impact on energy efficiency. Moreover, they show that it is possible to significantly improve the accuracy of motion by using an additional pose controller, which allows limiting the impact of the non-optimal geometric parameters of the robot and the slip of the wheels on trajectory tracking errors. However, the addition of the pose controller does not significantly affect the energy efficiency during the robot’s motion, which may be even worse in this case.

WITHDRAWN: Investigating the Polymer Structure Effects on SBS-Modified Asphalt Binders under Short-Term Aging through the Artificial Neural Networks, Genetic Algorithms, and Fuzzy Logic

SBS-modified asphalt (SBSMA) exhibits complicated aging behavior in the weathering environment due to oxidation of the matrix asphalt, degradation of the SBS, and disruption of the SBS-asphalt relationship. The weathering process of SBS-modified asphalt has been studied extensively. However, most of this research has taken a broad, environmental approach. This research delved into the nuanced effects of aging on low polymer-modified asphalt (LPMA) compositions integrated with a rejuvenating agent (RA), leveraging advanced computational intelligence methodologies. The study uniquely employed fuzzy logic, Artificial Neural Networks (ANN), and genetic algorithms to forecast and analyze the performance dynamics of distinct asphalt mixtures. Five asphalt mixtures were examined: a PG 58-28 binder served as the foundational benchmark, while the subsequent four used modified PG 58-28 with different ratios of Ethylene Vinyl Acetate (EVA) and sesame oil (RA). Assessment methodologies comprised the Resilient Modulus Test, Wheel Track Test, Flow Time, Direct Tension, and Quarter-Circle Bend tests. The ANN framework was instrumental in predicting rutting and crack trajectories, while fuzzy logic facilitated understanding the intricate interplays between component ratios and resultant performance metrics. Genetic algorithms optimized the EVA and RA ratios for enhanced efficacy. Initial results demonstrated that the amalgamation of EVA and RA strengthened the overall lifespan and rutting resilience of the asphalt composites. Enhanced blends, optimized using the genetic algorithm, exhibited improved resistance to initial crack formations relative to the baseline. As the aging process advanced, the modified blend's resilience to recurrent stress-induced cracks experienced minor reductions but paralleled the foundational benchmark. A harmonized combination, pinpointed via the genetic algorithm containing 6.5% EVA and 6% RA, emerged as the most proficient in amplifying durability, resistance against deformations, and immediate crack resistance.

Performance evaluation of asphalt binders incorporating surface-modified diatomite and bio-oil: A value-added utilization of natural resource

To study the effect of surface-modified diatomite (SMD) on bio-asphalt performance, the asphalt binders incorporating SMD and bio-oil (SMDB) was prepared with different dosages. The high-temperature characteristics of SMDB were assessed by consistency test, viscosity test, and dynamic shear rheometer (DSR). Meanwhile, the low-temperature characteristics of SMDB were evaluated by bending beam rheometer (BBR) and ductility test. The compatibility of SMDB was assessed by a storage stability test and a Fluorescence microscope (FM). The adhesion and chemical composition of SMDB were analyzed using the sessile drop method and Fourier transform infrared (FTIR) spectroscopy, respectively. Finally, the moisture stability and high-temperature properties of the SMDB mixture were studied using the tensile strength ratio (TSR) test and wheel track test, respectively. The preliminary results of this work show that the addition of SMD increases the viscosity, softening point, fatigue index, and rutting factor of asphalt and reduces the penetration. It is found that SMD improves the anti-aging performance, adhesion performance, and high-temperature stability of SMDB. Although SMD has a negative effect on the low-temperature properties and fatigue resistance of asphalt, the characteristics of SMDB at low temperatures are still superior to those of virgin asphalt. SMD at low content had little effect on the fatigue resistance of the bio-asphalt. Moreover, it is found that SMD is better than the original diatomite in enhancing bio-asphalt properties more significantly. In addition, the blending among SMD, asphalt matrix, and bio-oil is the physical modification, and the mixture has excellent storage stability. Finally, the mixture property testing results indicate that SMD improves the rutting and moisture resistance of the SMDB mixture.

Study on the interlayer critical response of asphalt pavement with different paving methods based on cohesive zone model

ABSTRACT Different paving methods of asphalt layers are the important factors that affect the interlayer performance and mechanical response of asphalt pavement structure. In order to further analyse the influence of different paving methods on the mechanical properties of asphalt structural layers, four kinds of asphalt pavement with different paving methods were selected as the research objects, namely continuous paving, discontinuous paving (tack coat), discontinuous paving (tack coat + dust), discontinuous paving (no tack coat). Firstly, the interlayer adhesion of asphalt pavement with different paving methods was studied by using the cohesive zone model (CZM). Secondly, different braking modes were selected to apply loads on asphalt pavement to explore the changing law of mechanical response of asphalt pavement under different braking modes. The test results show that the asphalt pavement with continuous paving has the strongest resistance to interlayer adhesion failure, while the asphalt pavement with discontinuous paving (no tack coat) has the weakest resistance to interlayer adhesion failure. In the braking state, the interlayer adhesion of the leading edge of the wheel track on asphalt pavement is most likely to fail, while the trailing edge of the wheel track is most likely to produce the transverse crack.

Influence of Axle Weight and Frequency on the Tribological Properties of Laser-Repaired 316L Stainless Steel Coatings in Railway Wheel Tread Braking

The impact of the complex braking environment on the service performance of the repair fusion cladding was studied, which is of great significance to improve the ability of the train wheel track system to resist the extremely harsh environment. In this paper, a 316L stainless steel coating was prepared using laser fusion cladding repair technology for the local damage location of the train wheel tread. The MS-HT1000 high-temperature wear tester was used for the experiment. Then, the influence of different braking conditions on the friction and wear performance of the repaired specimens at room temperature and high temperature was analyzed. The results showed that the microstructure of the laser-repaired 316L stainless steel coating was dendritic and eutectic, and its physical phase was mainly composed of austenite, Fe-Cr, and carbides. The wear rate increases with the rise in the shaft weight load, indicating that the higher the contact load, the more severe the wear. In contrast, the influence of the friction coefficient in a room temperature environment is less variable. With an increase in the braking frequency, the wear of the specimen firstly rises and then decreases, and when the frequency is 1 Hz, the value of the wear rate at room temperature is the largest, and the wear surface appears as more peeling layers, and a large amount of wear debris is randomly distributed, which manifests as the wear mechanism being characterized by abrasive wear and adhesive wear. Therefore, different factors affect the wear level of the material differently, with the axle weight load having the greatest influence. The relevant results help to provide corresponding theoretical references for the optimization of parameters under the braking condition of the wheel tread, which ensures the normal operation of the braking system when driving.

Identification of wheel track in the wheat field

Agriculture machinery navigating along permanent traffic lanes in the farmland may avoid causing extensive soil compaction. However, the permanent traffic lanes are frequently covered up or eliminated by following tillage practices. It is necessary to identify the wheel tracks designed as permanent traffic lanes in order to ensure the agriculture machinery travels along the designated wheel tracks when cultivating the field. This study proposed an identification method of wheel tracks based on the morphological characteristics of wheel tracks and the environmental conditions around the wheel tracks in the wheat fields. The proposed method first utilized the maximum interclass variance to identify the contours of the main part of the wheel track and the shadow regions around the wheel track’s edges. The main part of the wheel tracks was then separated from interference pixels by moving the centerline of the main part of the wheel track, which was derived by skeleton algorithm and curve fitting, towards the right or left edge of the wheel track at a specific distance. In a morphological opening operation, specific linear and circular structural elements were used to segment the shadow regions along the edge of the wheel track. The remaining wheel track was finally recognized by computing the complement of the region identified. After achieving the segmentation of wheel tracks, many reference points near the outside of the wheel track edge in the original image were chosen as fiducial points for evaluating the differences between the actual value and the recognized wheel track edge. The evaluation was based on computing the root mean squared error (RMSE) and the mean absolute error (MAE) of coordinates of reference points and recognized wheel track edge. The results showed that the largest RMSE and MAE were 24.01 pixels (0.0045 m) and 17.32 pixels (0.0032 m), respectively. The low values of RMSE and MAE reveal that the accuracy of the algorithm developed in this study is high, and using this algorithm may segment the wheel track in the wheat field accurately.