Slope Path Research Articles

Unmanned vehicle off-road path-planning method with comprehensive constraints on multiple environmental factors

ABSTRACT In complex off-road environments, different slopes, slope directions, and land types differently affect unmanned vehicle trafficability. Thus, we propose an unmanned vehicle off-road path-planning method with comprehensive constraints on multiple environmental factors. First, the influence of slope, aspect, and surface-coverage type on unmanned vehicle drivability was quantitatively evaluated, and the slope and land type influence layers were formed. Concurrently, a goal guidance layer was formed using the artificial potential field method. Second, the slope influence, land type influence, and goal guidance layers were used to quantitatively evaluate each grid’s pass cost value. Finally, the traditional A* algorithm, A* algorithm considering the impassable area, A* algorithm with comprehensive constraints, and Dijkstra algorithm with comprehensive constraints were used for path planning. The results show that the path slopes planned by A* algorithm with comprehensive constraints and Dijkstra algorithm with comprehensive constraints were smaller than those planned by A* algorithm and A* algorithm considering the impassable area; particularly, the length of the uphill path was shorter and the stability was better. The relevant research results provide methods and technical guidance for obtaining the shortest length, shortest time, and most stable and passable path in off-road environments.

Assessment of Park Paths and Trails for Physical Activity Promotion among Older Adults in Saudi Arabia: Feasibility and Future Directions.

A descriptive study design was used to assess five public parks in Riyadh, Saudi Arabia, from April to June 2022. Additionally, process, resource, and management assessments were also conducted. The PEAT was easy to use, but additions are recommended to increase relevance to older adults with chronic disease. Descriptive analyses revealed positive features, such as adequate lighting, but other features such as path slope were more variable. Study findings can guide the future use of the PEAT for older adult participants and inform environmental modifications.

Assessment of park paths and trails to promote physical accessibility among wheelchair users in Saudi Arabia.

Individuals with mobility disabilities are less likely to meet physical activity standards and are at greater risk of developing non-communicable chronic diseases at earlier ages. Public parks are an essential resource for participation in physical activity. However, environmental factors may limit the participation of wheelchair users. The objective of this study was to evaluate the feasibility of using the Path Environment Audit Tool (PEAT) and to explore the wheelchair accessibility of five public parks in Saudi Arabia through descriptive analysis. A descriptive study design was implemented to evaluate wheelchair accessibility features of five public parks in Riyadh, Saudi Arabia, and process, resource, and management assessments were conducted. Phone GPS-App Strava was used to track the segments and measure their distances. Audits in multiple parks using PEAT were time-consuming despite being user-friendly. The descriptive analysis of paths and trails across the five parks showed some positive features, such as adequate bollard/gate clearance, but the path slope and condition of the path surfaces were more variable. This study is the first to examine wheelchair accessibility in public parks in Saudi Arabia. Preliminary audits of paths/trials in five public parks revealed the strengths and weaknesses of accessibility and features that promote physical activity participation for wheelchair users. These findings can guide future use of PEAT in large-scale studies and inform environmental modifications.

Dual Independent Rotor Axial Flux Induction Motor for Electric Vehicle Applications

This article proposes a dual independent rotor axial flux induction motor (DIR-AFIM) with two degrees of freedom as a propulsion motor for an electric vehicle (EV). The performance of this motor in different operating conditions of the vehicle is discussed and investigated. This motor has two rotors that are mechanically independent of each other, providing driving force for the EV separately and enabling the removal of any mechanical or electrical differential. The propulsion motor can play the role of differential and also reduce the cost and complexity of the entire propulsion system in some extent. The finite element modeling of the proposed motor has been performed and the performance characteristics have been evaluated in three operating scenarios: flat path, sloped path, and turning path, taking into account the dynamics of the vehicle. Additionally, the accuracy of the simulations and modeling has been confirmed by performing some practical tests on the prototype machine. The results show that the simulations and measurements are in good agreement and the proposed propulsion system can be a suitable option for lightweight electric vehicles.

Reliability modeling of competing failure processes with multi‐stage degradation

AbstractIn this paper, reliability models of competing failure processes for the product subject to degradation and random shocks are established, which are accompanied by degradation path slope change caused by specific shock patterns. The two related failure modes are hard failure arising from different random shocks, and soft failure due to consecutive structure damage or combined with a sudden increment of degradation because of an identical random shock. In sophisticated equipment like aircraft engine systems, the degradation path of performance parameters is characterized by multi‐stages when the product is more prone to fatigue or accelerated aging, as a consequence of experienced shocks. This article analyzes five random shock patterns that can change the slope of the degradation path and studies an example to explain the application of proposed reliability models as well as the sensitivity analysis of parameters.

DEM-AIA: Asymmetric inclination-aware trajectory planner for off-road vehicles with digital elevation models

Planning safe and effective trajectories for off-road unmanned ground vehicles (UGV) is a critical Artificial Intelligence (AI) challenge that can benefit from recent advances in digital elevation models (DEM) for readily capturing accurate terrain geometry. Considering path slopes is crucial to preserve stability and assess terrain traversability at feasible speeds to optimize travel time, which is highly dependent on direction (i.e., pitch and roll). In this article, we propose a new DEM-based asymmetric inclination-aware (DEM-AIA) trajectory planner for ground vehicles. The planner is an any-angle variant of the A⋆ algorithm that computes pitch and roll estimations for each segment crossing cell triangles in the line-of-sight. Furthermore, we define a non-linear velocity constraints function that integrates information about tip-over safety limitations, maximum uphill and downhill slopes for the vehicle, and asymmetric modulation of nominal flat-ground velocity for all pitch and roll combinations. The planner produces a time sub-optimal trajectory with feasible speed references for each segment crossing a cell triangle. Moreover, we provide an extensive experimental analysis of inclination-aware performance on simulated and real-world DEMs as well as a comparison with state-of-the-art path planners adapted to travel-time optimization. An executable version of the planner with parameterizable variations is publicly available.

POL Reconstruction: a Necessity or an Accessory

The MCL is the knee ligament that is most commonly injured but is quite often neglected in terms of in-depth research and understanding. This is due to the belief in good healing abilities that there is a belief that MCL injuries are almost certain to be cured conservatively. Commonly, recurrent rupture after ACL reconstruction is due to neglect of MCL rupture. This prompted researchers and orthopedic sports surgeons to think about the importance of the MCL, initiate in-depth research on the MCL, and initiate repair of the ligament. Surgical indications include high-grade MCL injuries, valgus instability that persists on conservative therapy, and low-grade MCL injuries with other ligamentous injuries. The MCL consists of the superficial MCL (sMCL), deep MCL (dMCL) and the Posterior Oblique Ligament (POL).It stabilizes the medial of the knee against the valgus and rotation. The sMCL attachment to the femur covers the EM (Epicondyle Medial) and has a long attachment proximal to the tibia distally. The course of the dMCL has a sloping path from its attachment at the posterior distal of EM to the anterior distal of the proximal tibia. The posterior oblique ligament consists of three arms: the superficial, central (tibial), and capsular. The central arm is the largest and thickest part of the POL. The POL attachment to the medial condyle of the femur is somewhat more posterior and proximal than the EM or posterior and distal to the adductor tubercle, extending to the distal aspect of the semimembranosus tendon and is a thickening of the posterior medial capsule, with a distinct attachment to the medial meniscus. It is fused anteriorly with the sMCL but can be identified by the orientation of the fibers. The sMCL biomechanics found tension in the anterior aspect of the ligament when flexed about 90 degrees and externally rotated. In the posterior part of the sMCL, tension during full extension and internal rotation. The anterior part of the dMCL relaxes at 0-30 degrees and tension at an angle of 60 degrees to full flexion, while the posterior part of the dMCL relaxes more when flexed at 0-100 degrees. The POL is the posterior part of the MCL complex, which will be tensioned during Full Extension and internal rotation. The MCL complex is different in its response to changes in length to the extension, flexion, and knee rotation. The MCL is not isometric. The role of POL, which is quite prominent in the medial corner of the posterior knee, holds the movement of internal rotation, so this ligament is not accessory. Rupture of POL requires reconstruction to maintain the internal rotation stability of the knee joint. Furthermore, in performing reconstruction, the POL must be tightened and fixed in full knee extension and neutral rotation to reproduce its anatomical length and prevent over-tightening.

Possibilities for the Development of an Electric Hybrid Skidder Based on Energy Consumption Measurement in Real Terrain Conditions

Growing demand for forest machines that cost less to operate than current compared to traditional hydraulic and mechanical ones, along with regulatory pressures for lower emissions, is increasing manufacturers’ interest in developing electric and hybrid drives. While purely electric drives of forest machines meet a lot of bottlenecks (costs of the electric components, battery durability, duration of charging, access to the electrical grid, size of batteries that can ensure enough energy for 8 h working time), electric hybrid drives offer a favorable solution for the propulsion of forestry machinery in terms of lower fuel consumption and improved efficiency. Among all forest vehicles, specialized forest tractors (skidders), so far, have not been considered for forest vehicles with hybrid drive capabilities. A skidder is a forest-articulated self-propelled vehicle for pulling trees or parts of trees. In most countries in southern Europe, the use of skidders equipped with forest winches is the most common technique for timber extraction. The first goal of the research is to develop methods for measuring the energy consumption of skidders at different operating tasks and under different field conditions. Research was performed on the skidder Ecotrac 140V (from Croatian producer Hittner Ltd.) during timber extraction in mountainous terrains in Lika–Senj County. The skidder was equipped with a measuring device WIGO-E (Telematic Data collector) gateway with an integrated GPS system, which ensured data were collected from sensors and motor and stored in a computer via CANBUS and data transfer with GSM to Web platforms. Additionally, a fuel-flow meter was installed on the skidder. Data on fuel consumption (mL), position (traveling route), detection of winch work, engine rpm (min−1), engine torque (% of max), throttle position (%), and engine temperature were measured with a sampling frequency of 5 s. Furthermore, skidder load volumes per cycles and slopes of tractor paths were constantly measured. The paper shows the skidder’s energy consumption per day, work cycle, and individual work procedure with regard to the size of the load, the slope of the tractor path, and the direction of movement based on overlapping and merging all measurement data. Using mathematical and simulation models of the drive with defined operating cycles obtained by measurement, the possibilities of the hybrid drive and the dimensions of the elements of the hybrid drive (internal combustion engine, electric motor, batteries, control unit) were determined and are presented in this paper.

User Association in a Heterogeneous Vehicular Network With Roadside Units and Vehicle Relays

This letter investigates the behavior of users in a vehicular network where there are two types of transmitters—roadside units (RSUs) and vehicle relays. We address the unique network geometry of such a network by adapting the Cox point process, the double slope path loss, and the strongest average power user association. We derive the probability that users are associated with either RSUs or relays. The association formula explicitly quantifies the change of user association behavior when the heterogeneous vehicular network has two types of transmitters distinctive in their transmit powers and densities. Leveraging this letter, one can explore the potential and benefits of heterogeneous vehicular networks with RSUs and vehicle relays.

Capacited Vehicle Routing Problem with CO2 Emission Minimization Considering Path Slopes

This work presents the application of a CO2 emission estimation function for cargo vehicles on a Capacited Vehicle Routing Problems (CVRP) setting, considering route’s slopes variation. Comparisons were established with functions minimizing fuel consumption and route length in a case study about selective collection of recyclable waste at Sorocaba, state of São Paulo, Brazil. Routes with lower emissions have been achieved without significantly increasing fuel consumption or distance traveled.

MM-Wave HetNet in 5G and beyond Cellular Networks Reinforcement Learning Method to improve QoS and Exploiting Path Loss Model

This paper presents High density heterogeneous networks (HetNet) which are the most promising technology for the fifth generation (5G) cellular network. Since 5G will be available for a long time, previous generation networking systems will need customization and updates. We examine the merits and drawbacks of legacy and Q-Learning (QL)-based adaptive resource allocation systems. Furthermore, various comparisons between methods and schemes are made for the purpose of evaluating the solutions for future generation. Microwave macro cells are used to enable extra high capacity such as Long-Term Evolution (LTE), eNodeB (eNB), and Multimedia Communications Wireless technology (MC), in which they are most likely to be deployed. This paper also presents four scenarios for 5G mm-Wave implementation, including proposed system architectures. The WL algorithm allocates optimal power to the small cell base station (SBS) to satisfy the minimum necessary capacity of macro cell user equipment (MUEs) and small cell user equipment (SCUEs) in order to provide quality of service (QoS) (SUEs). The challenges with dense HetNet and the massive backhaul traffic they generate are discussed in this study. Finally, a core HetNet design based on clusters is aimed at reducing backhaul traffic. According to our findings, MM-wave HetNet and MEC can be useful in a wide range of applications, including ultra-high data rate and low latency communications in 5G and beyond. We also used the channel model simulator to examine the directional power delay profile with received signal power, path loss, and path loss exponent (PLE) for both LOS and NLOS using uniform linear array (ULA) 2X2 and 64x16 antenna configurations at 38 GHz and 73 GHz mmWave bands for both LOS and NLOS (NYUSIM). The simulation results show the performance of several path loss models in the mmWave and sub-6 GHz bands. The path loss in the close-in (CI) model at mmWave bands is higher than that of open space and two ray path loss models because it considers all shadowing and reflection effects between transmitter and receiver. We also compared the suggested method to existing models like Amiri, Su, Alsobhi, Iqbal, and greedy (non adaptive), and found that it not only enhanced MUE and SUE minimum capacities and reduced BT complexity, but it also established a new minimum QoS threshold. We also talked about 6G researches in the future. When compared to utilizing the dual slope route loss model alone in a hybrid heterogeneous network, our simulation findings show that decoupling is more visible when employing the dual slope path loss model, which enhances system performance in terms of coverage and data rate.

Satellite detection of snow avalanches using Sentinel-1 in a transitional snow climate

Snow avalanches endanger lives and infrastructure in mountainous regions worldwide. Consistent and accurate datasets of avalanche events are critical for improving hazard forecasting and understanding the spatial and temporal patterns of avalanche activity. Remote sensing-based identification of avalanche debris allow for the acquisition of continuous and spatially consistent avalanches datasets. This study utilizes expert manual interpretations of Sentinel-1 synthetic aperture radar (SAR) satellite backscatter images to identify avalanche debris and compares those detections against historical field records of observed avalanches in the transitional snow climates of Wyoming and Utah, USA. We explore and quantify the ability of an expert using Sentinel-1 (a SAR satellite) images to detect avalanche debris on a dataset comprised exclusively of dry slab avalanches. This research utilized four avalanche cycles with 258 field reported avalanches. Due to individual avalanches appearing in multiple overlapping Sentinel-1 images this resulted in 506 potential detections of avalanches in our SAR images, representing the possibility of multiple detections of a single avalanche event in different images. The overall probability of detection (POD) for avalanches large enough to destroy trees or bury a car (i.e., ≥D3 on the destructive size scale) was 65%. There was a significant variance in the POD among the 13 individual SAR image pairs considered (15–86%). Additionally, this study investigated the connection between successful avalanche detections and SAR-specific, topographic, and avalanche type variables. The most correlated variables with higher detection rates were avalanche path lengths, destructive size of the avalanche, incidence angles for the incoming microwaves, average path slope angle, and elapsed time between the avalanche and a Sentinel-1 satellite image acquisition. This study provides a quantification of the controlling variables in the likelihood of detecting avalanches using Sentinel-1 backscatter temporal change detection techniques, as specifically applied to a transitional snow climate.

Optimizing the Life-Cycle Path of Pension Premium Payments and the Pension Ambition in the Netherlands

We determine the optimal life-cycle path of pension premiums during the working ages and pension benefits during retirement, assuming that households can choose these freely. We calibrate the model on Dutch data. The optimization takes into account the fact that incomes generally rise during the working ages and that children are generally present in young households. Both features lead to an upward sloping path of optimal pension premium rates over the working life, while under the current pension system this is rather flat. The welfare gains from implementing the optimal pension system depend on the specification of the model, but can be sizable. A potentially lower return on pension assets in the future implies a further delay of optimal pension premiums during the working ages and a lower optimal pension benefit after retirement. Differentiating the path of pension premiums and benefits according to the level of educational attainment of the main income earner brings only small additional welfare gains compared to the situation in which pension premium rates are based on the average income profile in the Dutch economy.

A Study on the Effect of Features Obtained From Signal Segments on Classification Success

Successful classification depends on the selection of the distinctive features and the effective channel subset used in the classification. In this study, novel and practical methods are proposed for determining the distinctive features and detecting effective channel subsets in the multi channel classification systems such as EEG. Two different feature extraction methods are compared in the study. The first one is based on classical Wavelet transform and the second is our proposed approach which used the slope of signal segments. Feature vectors are generated from some signal properties such as the mean, standard deviation, numerical integral of the Wavelet coefficients for classical Wavelet transform based feature extraction method. For our proposed method, only the slopes of signal segments are used for the feature vectors. In the proposed Signal Path Slope (SPS) feature extraction method, differently from the classical Wavelet based method, a Savitzky Golay (S-G) filter with an optimal frame length is applied to the signal before segmentation to make the path of the signal more prominent in time domain. In this way, the distinctive classification features are extracted by using S-G filter. For channel selection, an iterative channel selection method based on the classification results which divide the dataset labelled dataset into two groups as % 90 pre-training and %10 pre-test data is proposed. The dataset provided as dataset-3 in BCI competition IV is used in this study. The feature vectors extracted by using the proposed methods are classified for each method with the Support Vector Machine classifier. The results are given comparatively and it is observed that our proposed method has less computational complexity and more successful classification than Wavelet based classical feature extraction methods. The highest classification accuracies of % 67.74 and % 49.27 for subject-1 and subject-2 respectively are obtained with a low dimensional feature vector by proposed SPS feature extraction method. The classification accuracies achieved in the study are increased by % 8.24 for subject-1 and % 14.97 for subject-2 when compared average of the competition results. The significant increase in the success for both subjects shows the consistency of the proposed methods. By this study, it is observed that there is a subject-specific signal pattern related to motor imagery tasks in the brain. This pattern distinctive features is successfully determined by using the proposed methods.

Centrifugal Compressor Polytropic Performance—Improved Rapid Calculation Results—Cubic Polynomial Methods

This paper presents a new improved approach to calculation of polytropic performance of centrifugal compressors. This rapid solution technique is based upon a constant efficiency, temperature-entropy polytropic path represented by cubic polynomials. New thermodynamic path slope constraints have been developed that yield highly accurate results while requiring fewer computing resources and reducing computing elapsed time. Applying this thermodynamically sound cubic polynomial model would improve accuracy and shorten compressor performance test duration at a vendor’s shop. A broad range of example case results verify the accuracy and ease of use of the method. The example cases confirm the cubic polynomial methods result in lower calculation uncertainty than other methods.

Justification of Parameters of a Robotic Platform for Strawberry Harvesting

One of the most important tasks when performing automated harvesting of berry and fruit crops in the field is the accurate determination of the fruits and berries boundaries using computer vision cameras in various climatic conditions. (Research purpose) The research purpose is in studying the conditions of work of the robotic harvesting platform, developing a method of berries picking and justifying the parameters of the robotic platform due to the conditions of work in the area of strawberry cultivation on the conventional technology with the distance between the ridges of 90 centimeters and a plant height of 40 centimeters. (Materials and methods) The article presents a theoretical calculation of the main design and technological indicators of the robotic platform. The article describes the electronic components and assemblies that the robotic platform is made of. Authors analyzed the technological parameters of plantings to justify the effectiveness of the robotic platform. (Results and discussion) The basic dimensions of the robotic platform is: the total weight should not exceed 4 kilograms, the required transport speed is of 2 meters per second, the speed during the technological operation is of 0.3 meters per second, the overcoming slope is at least 20 degrees. The parameters that ensure increased efficiency of the platform when harvesting strawberries is as follow: width is of 320 millimeters; height is of 300 millimeters; length is of 570 millimeters; ground clearance is of 80 mm; coefficient of reserve of traction force without a path slope is of 2.4; power of electric motors is of 16.4 watts; operating time is of 2.2 hours, operating speed ispositional, maximum speed is of 4 meters per second. (Conclusions) Authors have proposed the design of a platform for robotic picking of garden strawberry, which compares favorably with analogues in that it makes it possible to increase the efficiency of picing by using inexpensive components, high mobility and the ability to simultaneously work on the field of several dozen similar platforms. It was found that the low weight and small dimensions allow reducing the mechanical impact on the target object, preserving the appearance and quality characteristics of the strawberry crop.

Factors Affect Slipping of Automobiles

This paper presents analysis for the slipping phenomenon in automobiles; the parameters affects slipping of automobiles are discussed. An analytical equation is constructed to relate all factors affect slipping ratio. Some relations are predicted to show the factors affect the slipping in automobiles. It is found that the parameters affect slipping can be summarized as: radius of curvature of the curve, angle of the curve (slope), RPM of the tire, radius of the tire in addition to the nature of the road. It is found that: as the normal acceleration increases the slipping ratio decreases, as the RPM of the tire increase the slipping ratio increases and as the radius of the tire increases the slipping percent increases. It is obvious that as the path slope (tan θ) increases the slipping value decreases. It is noticed that: as the radius of curvature increase the slipping % decrease which is logic, since the slipping on straight dry path is nearly close to zero. Also it is noticed that: as the tire radius decreases the slipping % increases.

Uplink coverage probability and spectral efficiency for downlink uplink decoupled dense heterogeneous cellular network using multi-slope path loss model

Low powered node densification leading to dense and ultra dense heterogeneous networks is a feature of 5th generation cellular networks. With this densification, the nature of the link between the transmitter and receiver in the network requires even more accurate and reliable models. For performance analysis of such networks where the rates of signal loss over distance becomes a significant parameter, more accurate path loss models should be used when analyzing user equipment (UE) association probability, coverage probability and average spectral efficiency. In this paper, we have considered a two-tier dense heterogeneous cellular network incorporating downlink uplink decoupled technique and have derived generalized expressions for UE association probability, decoupled uplink coverage probability and decoupled uplink average spectral efficiency using multi-slope path loss model. This path loss model broadly incorporates the effects of physical environment on the distance-dependent path loss. For simulation purpose, we have compared network performance while considering single-slope and dual-slope path loss models. The derived analytical expressions have been validated through network simulations and found in good agreement. Through comparison, it has been found that the decoupled UE association probability and uplink coverage probability is higher when incorporating multi-slope path loss model as compared to single-slope path loss model while the decoupled uplink spectral efficiency is observed to be lower when incorporating dual slope path loss model.

Development of a new analytical water film depth (WFD) prediction model for asphalt pavement drainage evaluation

Pavement drainage Evaluation is conducive to reduce hydroplaning risk. Empirical Water Film Depth (WFD) models are low accuracy and have limited application scope. This study develops an analytical WFD model by simulating the dynamic of sheet flow. Based on the field data of 10 test sites the analytical model and two empirical models are applied for WFD prediction. Refer to the field measured WFD, correlation tests are applied, and the findings include: the intervening factors on WFDs are ranked as follows rainfall intensity, pavement permeability, flow path length, flow path slope, and texture depth; the proposed analytical model is more accurate than Gallaway model and PAVDRN model. The significance is twofold. First, accumulated rainwater is involved in WFD estimation. Second, the hazardous ponding location is identified, so that pavement engineers can take remedial measures to reduce potential hydroplaning.

Hydraulic system elaboration and simulation for single-drive light-load monorail locomotive in fully mechanized coal mining applications

To solve the problem of light-load material transportation at the top and bottom of fully mechanized mining face, a hydraulic control system for single-drive monorail light-duty locomotive was designed. The importance of proper clamping force is mainly introduced, and the clamping pressure and braking time are determined. The relationships between the average travelling speed of the locomotive under different loads, the load and slope path of the locomotive are obtained. The simulation path was designed according to the field operation, and the AMESIM software was used for modeling and simulation. The simulation results meet the technical and engineering requirements and briefly introduce the use of the rotary valve in the traction circuit and the clamping circuit.