Downhill Slope Research Articles

Peak Oxygen Uptake is Slope Dependent: Insights from Ground Reaction Forces and Muscle Oxygenation in Trained Male Runners

BackgroundThe aim of this study is to explore the effect of treadmill slope on ground reaction forces and local muscle oxygenation as putative limiting factors of peak oxygen uptake in graded maximal incremental running tests. Thirteen trained male runners completed five maximal incremental running tests on treadmill at − 15%, − 7.5%, 0%, 7.5% and 15% slopes while cardiorespiratory and local muscle oxygenation responses as well as ground reaction forces were continuously recorded. Blood lactate concentration and isometric knee extensor torque were measured before and after each test.ResultsPeak oxygen uptake was lower at − 15% slope compared to all other conditions (from − 10 to − 17% lower, p < 0.001), with no difference between − 7.5 and + 15% slope. Maximal heart rate and ventilation values were reached in all conditions. The negative external mechanical work increased from steep uphill to steep downhill slopes (from 6 to 92% of total external work) but was not correlated with the peak oxygen uptake reduction. Local muscle oxygenation remained higher in − 15% slope compared to level running (p = 0.003).ConclusionsSimilar peak oxygen uptake can be reached in downhill running up to − 7.5% slope. At more severe downhill slopes (i.e., − 15%), greater negative muscle work and limited local muscle deoxygenation occurred, even in subjects familiarized to downhill running, presumably preventing the achievement of similar to other condition’s peak oxygen uptake.Key PointsTrained male runners can reach like level running V̇O2peak at moderate but not at severe negative slope.Negative external mechanical work increases with increasing negative slope.At maximal intensity Vastus Lateralis muscle oxygenation is higher in steep negative slope.Knee extensor isometric muscle torque is preserved after maximal level and uphill running, but reduced after downhill running, despite lower blood lactate.Progressive reduction of V̇O2 at maximal effort with increasing negative slope might be related to the metabolic consequences of increased lower limb negative external work (i.e., eccentric muscle actions).

Painful distortions: people with painful knee osteoarthritis have biased visuospatial perception of the environment.

Visuospatial perception is thought to be adaptive-ie, hills are perceived as steeper when capacity is low, or threat is high-guiding appropriate interaction with the environment. Pain (bodily threat) may similarly modulate visuospatial perception, with the extent of modulation influenced by threat magnitude (pain intensity, fear) and associated with behaviour (physical activity). We compared visuospatial perception of the environment between 50 people with painful knee osteoarthritis and 50 age-/sex-matched pain-free control participants using 3 virtual reality tasks (uphill steepness estimation, downhill steepness estimation, and a distance-on-hill measure), exploring associations between visuospatial perception, clinical characteristics (pain intensity, state and trait fear), and behaviour (wrist-worn accelerometry) within a larger knee osteoarthritis group (n = 85). People with knee osteoarthritis overestimated uphill (F 1,485 = 19.4, P < 0.001) and downhill (F 1,480 = 32.3, P < 0.001) steepness more so than pain-free controls, but the groups did not differ for distance-on-hill measures (U = 1273, P = 0.61). There was also a significant group x steepness interaction for the downhill steepness task (F 4,480 = 3.11, P = 0.02). Heightened overestimation in people with knee osteoarthritis relative to pain-free controls increased as downhill slopes became steeper. Results were unchanged in a replication analysis using all knee osteoarthritis participants (n = 85), except the downhill steepness interaction was no longer significant. In people with knee osteoarthritis, higher state fear was associated with greater over-estimation of downhill slope steepness (rho = 0.69, P < 0.001), and greater visuospatial overestimation (distance-on-hill) was associated with lower physical activity levels (rho = -0.22, P = 0.045). These findings suggest that chronic pain may shift perception of the environment in line with protection, with overestimation heightened when threat is greater (steeper hills, more fearful), although impact on real-world behaviour is uncertain.

The contribution of lower-limb joint quasi-stiffness to theoretical leg stiffness during level, uphill and downhill running at different speeds.

Humans change joint quasi-stiffness (k joint) and leg stiffness (kleg) when running at different speeds on level ground and during uphill and downhill running. These mechanical properties can inform device designs for running such as footwear, exoskeletons and prostheses. We measured kinetics and kinematics from 17 runners (10 M; 7 F) at three speeds on 0°, ±2°, ±4° and ±6° slopes. We calculated ankle and knee k joint, the quotient of change in joint moment and angular displacement, and theoretical leg stiffness (klegT) based on the joint external moment arms and k joint. Runners increased k ankle at faster speeds (p < 0.01). Runners increased and decreased the ankle and knee contributions to klegT, respectively, by 2.89% per 1° steeper uphill slope (p < 0.01) during the first half of stance. Runners decreased and increased ankle and knee joint contributions to klegT, respectively, by 3.68% during the first half and 0.86% during the second half of stance per 1° steeper downhill slope (p < 0.01). Thus, biomimetic devices require stiffer k ankle for faster speeds, and greater ankle contributions and greater knee contributions to klegT during the first half of stance for steeper uphill and downhill slopes, respectively.

A Multi-Agent Driving-Simulation Approach for Characterizing Hazardous Vehicle Interactions between Autonomous Vehicles and Manual Vehicles

The advent of autonomous vehicles (AVs) in the traffic stream is expected to innovatively prevent crashes resulting from human errors in manually driven vehicles (MVs). However, substantial safety benefits due to AVs are not achievable quickly because the mixed-traffic conditions in which AVs and MVs coexist in the current road infrastructure will continue for a considerably long period of time. The purpose of this study is to develop a methodology to evaluate the driving safety of mixed car-following situations between AVs and MVs on freeways based on a multi-agent driving-simulation (MADS) technique. Evaluation results were used to answer the question ‘What road condition would make the mixed car-following situations hazardous?’ Three safety indicators, including the acceleration noise, the standard deviation of the lane position, and the headway, were used to characterize the maneuvering behavior of the mixed car-following pairs in terms of driving safety. It was found that the inter-vehicle safety of mixed pairs was poor when they drove on a road section with a horizontal curve length of 1000 m and downhill slope of 1% or 3%. A set of road sections were identified, using the proposed evaluation method, as hazardous conditions for mixed car-following pairs consisting of AVs and MVs. The outcome of this study will be useful for supporting the establishment of safer road environments and developing novel V2X-based trafficsafetyinformation content that enables the enhancement of mixed-traffic safety.

Pedestrian dynamics on slopes: Empirical analysis of level, uphill, and downhill walking

Pedestrian safety on inclined walking facilities merits greater attention than that on level surfaces. Crowd accidents and domino effects are more likely to occur on slope walkways, especially at high crowd densities, as in the tragic case of the 2022 Itaewon Halloween crowd crush in South Korea. However, experimental investigations of the pedestrian dynamics on slopes with varying inclinations are scarce. In this study, a controlled experiment involving 48 participants was conducted to investigate the differences in pedestrian movement characteristics during level, uphill, and downhill slope walking. A wide range of slope inclinations was considered, namely 0°, 3°, 7°, 12°, 17°, and 22°. The results demonstrated that walking speeds uphill are lower than those on flat terrains, and uphill speeds decrease with increasing inclination. In contrast, increased slope inclinations do not always correspond to reduced downhill speeds. Notably, at inclinations of 3° and 7°, the downhill speed exceeds that of level walking, suggesting that a mild downhill slope can facilitate faster movement. Compared with downhill walking, pedestrians exhibit more lateral motion and significantly lower speeds (p < 0.01) when walking uphill at the same inclination. However, the average flow rate during downhill walking is lower than those observed on flat ground and uphill terrain. This difference may be attributable to the lower pedestrian density during downhill walking to reduce the likelihood of falling. These findings can enhance the understanding of pedestrian dynamics on ramps and have significant implications for the design of safer inclined walking facilities and prevention of potential disasters on such walkways.

Stability and safety analysis of mixed traffic flow considering network function degradation and platoon driving on the road with a slope

Considering the influence of slope sections and random degradation of the communication function of cooperative adaptive cruise control vehicles and the effect of the cooperative adaptive cruise control vehicle group driving, a linear stability criterion for heterogeneous traffic flow composed of cooperative adaptive cruise control vehicles and humanly-driven vehicles on slopes is derived, and a parameter sensitivity analysis is carried out. On this foundation, the safety of traffic flow on two-lane roads up and down hills is simulated while considering the lane-changing behavior of automobiles. The stability study shows increased cooperative adaptive cruise control vehicle penetration and uphill gradient will help improve traffic flow stability. In contrast, the increase in the downhill slope will intensify the transmission amplitude of the disturbance. When vehicle starting sensitivity is 2.5, and the gradient is 60, the minimum cooperative adaptive cruise control vehicle penetration required for mixed traffic flow to maintain stability on a downhill at any initial equilibrium speed is 85%, and the minimum penetration required on an uphill is 73%, and this proportion decreases with the increase in the uphill gradient and increases with the rise in the downhill slope. According to the safety study, increasing cooperative adaptive cruise control vehicle penetration and implementing lane-changing rules will improve traffic flow safety. Compared with the straight section, under the same conditions, the traffic flow safety of the uphill section is the best, and the safety of the downhill section is poor, which is consistent with the stability analysis results. This study is of great significance for future traffic control strategies for mountain roads.

A multi-level analysis on the causes of train-pedestrian collisions in Southwest China 2011–2020

Collisions between trains and pedestrians are the primary cause of railway casualties. However, there remains a lack of comprehensive understanding regarding the underlying causes of this phenomenon. This study employs a multi-level approach to investigate the factors associated with the occurrence and severity of train-pedestrian collisions. The investigation is based on 2160 independent cases that occurred in southwest China from 2011 to 2020. Multiple contributing factors related to the victim, train, track, and socio-economic status of the surrounding district were examined, utilizing information from various sources. At the county level, several risk factors were identified in predicting the occurrence rate. These factors include higher population density and a greater number of normal-speed stations. However, the presence of high-speed train stations did not exhibit any significant impact. Additionally, the study found that regulations pertaining to protective fences were highly effective in reducing the occurrence rate. Regarding the prediction of collision severity, certain factors were found to increase the death rate. These factors include young men as victims, engaging in lying down or crossing behaviors, higher train speeds, gentle downhill slopes, lower education levels, and a higher proportion of the labor force. These findings emphasize the necessity of adopting a comprehensive perspective when examining the causes of train-pedestrian collisions. Furthermore, it underscores the significance of considering the notable differences between rapidly developing countries such as China and developed countries. Based on our findings, we also provide corresponding policy suggestions.

Influence of walkway slope on single-file pedestrian flow dynamics: Results from an experimental study

Sloping walkways are common pedestrian traffic facilities in modern cities, especially, in some cities located in mountainous terrain, such as Hong Kong, and Zurich. Compared with level walkways, sloping walkways may lead to the decrease in pedestrian flow efficiency, and are more prone to trigger crowd disasters at extreme crowd densities, for example, recent crowd stampede event in Itaewon, South Korea, did happen on a narrow ramp with an extreme crowd density. Therefore, it is important to study pedestrian flow dynamics on ramps. In this paper, we conducted single-file pedestrian flow experiments in 0°, 3°, 5°, 7°, 9°, 12°, 17°, 22°, 27° uphill and downhill conditions, and analyzed contrastively the influence of walkway slope on pedestrian flow dynamics. Our main findings are as follows. (i) Pedestrian flow efficiency is the highest in 7° downhill condition, indicating that a small downhill slope is advantageous to pedestrian flowing. (ii) Whether it is uphill or downhill, the ramp steeper than 7° will significantly decrease pedestrian flow efficiency, therefore is disadvantageous to pedestrian flowing. (iii) For a ramp, uphill and downhill pedestrian flow efficiencies are not equal. Downhill pedestrian flow efficiency is always larger than uphill pedestrian flow efficiency. These findings provide important guidance for the design of sloping walkways and the safety management of pedestrian crowds on sloping walkways.

Research on Speed Control Methods and Energy-Saving for High-Voltage Transmission Line Inspection Robots along Cable Downhill

To ensure the safe operation of high-voltage transmission line inspection robots during downhill descents without power and extend their range after a single charge, this paper proposes an energy-saving speed control method for the inspection robot’s walking wheel motor on downhill slopes by integrating feedback braking and fuzzy PID control. By combining the parameter equation of the overhead catenary line and the structural characteristics of the overhead transmission line, this paper analyzes the relationship between the driving torque of the inspection robot’s wheels and the horizontal displacement along the transmission ground wire before and after descending. Based on this analysis, a speed control and energy recovery scheme is developed for the inspection robot, which combines front-wheel feedback braking with rear-wheel regenerative braking. The fuzzy PID method is utilized to adjust the PWM duty cycle to achieve energy-efficient speed control of the inspection robot’s rear walking wheels. Additionally, to improve the energy density and specific power of the robot’s energy storage unit, a composite power source consisting of lithium batteries and supercapacitors is employed to recover energy from the front walking wheels through feedback braking. The combined simulation results indicate that, compared to fuzzy control and PID control, fuzzy PID control better regulates the robot’s speed under varying slopes, wind resistance, and cable roughness. A downhill speed control system for the inspection of the robot’s walking wheel motor was designed, and its effectiveness was validated through simulated high-voltage line experiments. The fuzzy PID control was demonstrated to effectively maintain the rear walking wheel speed within the targeted range during downhill descents. When descending along a fixed 30° angle cable, the fuzzy PID control resulted in an increase of 5.28% and 14.26% in the state of charge (SOC) of the supercapacitor compared to PID control and fuzzy control, respectively. Moreover, when descending along fixed angle cables of 10°, 20°, and 30°, as well as a variable angle cable ranging from 30° to 0°, the SOC of the supercapacitor increased by 17.55%, 26.25%, 38.45%, and 31.29%, respectively. This demonstrates the effective absorption of regenerative braking energy during the robot’s downhill movement.

An observational study comparing ormeloxifene with evening primrose oil for benign breast diseases

Background: Fibroadenosis, popularly termed aberrations of normal development and involution (ANDI), is by far the most common female breast presentation to a surgeon. ANDI accounts for the most common breast lumps in women &lt;30 years of age. Mastalgia, a significant spectrum of ANDI, is usually classified as (1) cyclical mastalgia (more common) and (2) non-cyclical mastalgia. Breast nodularity, the other spectrum of ANDI may either present as a predominant feature or coexist with mastalgia. Aims and Objectives: The aims of this study were to comparatively study ormeloxifene and evening primrose oil with respect to regression of fibroadenosis and mastalgia and evaluate their side effects. Materials and Methods: This prospective study was conducted in the Department of General Surgery of Calcutta National Medical College and Hospital, Kolkata from February 15th, 2021 to February 14th, 2022, after obtaining prior Institutional Ethical Committee Clearance. Two hundred and eighty patients were equally divided into two groups of 140 in each and screened for inclusion in this study. Results: At the start of treatment, Group A (Ormeloxifene) presented with a mean visual analog scale (VAS) score value of 5.71, while patients of Group B presented with a similar mean VAS score value of 5. Group B recorded a VAS score of 4.50 at the end of the 6th month, while Group A recorded a significant downhill slope of negligible mean VAS score value of 0.80 at the of the 6th month. In breast nodularity gradings too, Group A showed significant down staging of grades returning, 95% confidence interval at the end of 6th month as 1.144, while 2.280 was recorded for Group B. Conclusion: Benign breast disease is a common presenting problem in females of reproductive age. Ormeloxifene can be a better alternative to evening primrose oil in both cyclical and non-cyclical types of mastalgia. Larger trials are however required, to finally conclude on.

Changes in Distance between a Wearable Robotic Exoskeleton User and Four-Wheeled Walker during Gait in Level and Slope Conditions: Implications for Fall Prevention Systems

When walking with wearable robotic exoskeletons (WRE) in people with spinal cord injury, the distance between the user and the walker is one of the most important perspectives for ensuring safety. The purpose of this study was to clarify the distance between WRE users and four-wheeled walkers (4WW) while walking on level and sloping surfaces. To eliminate the effects of variation in neurological conditions, 12 healthy subjects participated. All participants ambulated using the WRE and the 4WW on level and sloping surfaces. The outcomes were the mean distances between the WRE users and the 4WWs in the level and slope conditions. To examine the influence of uphill and downhill slopes on distance, comparisons were conducted between the uphill or downhill conditions and the respective transitional periods. In the uphill condition, the mean distances were significantly greater than that in the level condition. Conversely, the mean distance moving downhill was significantly shorter than that in the level condition. Changes in the distance between the WRE user and the 4WW might increase the risk of falling forward on an uphill slope and backward on a downhill slope. This study’s results will assist in developing a new feedback system to prevent falls.

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.

Study on Emission Characteristics of Heavy Duty Diesel Vehicle in Plateau Environment

In order to understand the emission characteristics of National VI heavy-duty diesel vehicles on long slopes under full load in plateau environment, an N3 heavy-duty diesel vehicle was tested on actual road emissions to study the instantaneous emissions of pollutants from heavy-duty diesel vehicles on long uphill and downhill slopes and compare their emission factors. The results show that the engine exhaust temperature decreases with the decrease of altitude. When heavy diesel vehicles are going uphill, with the increase of road slope, NOx emissions show a downward trend and PN emissions show an upward trend. However, when heavy diesel vehicles go downhill, with the decrease of road slope, NOx emissions show an increasing trend and PN emissions show a decreasing trend. When heavy diesel vehicles go uphill, the pollutant emission is worse than that when they go downhill.

Effects of powered versus passive-elastic ankle foot prostheses on leg muscle activity during level, uphill and downhill walking.

People with transtibial amputation (TTA) using passive-elastic prostheses have greater leg muscle activity and metabolic cost during level-ground and sloped walking than non-amputees. Use of a stance-phase powered (BiOM) versus passive-elastic prosthesis reduces metabolic cost for people with TTA during level-ground, +3° and +6° walking. Metabolic cost is associated with muscle activity, which may provide insight into differences between prostheses. We measured affected leg (AL) and unaffected leg (UL) muscle activity from ten people with TTA (6 males, 4 females) walking at 1.25 m s-1 on a dual-belt force-measuring treadmill at 0°, ±3°, ±6° and ±9° using their own passive-elastic and the BiOM prosthesis. We compared stride average integrated EMG (iEMG), peak EMG and muscle activity burst duration. Use of the BiOM increased UL lateral gastrocnemius iEMG on downhill slopes and AL biceps femoris on +6° and +9° slopes, and decreased UL rectus femoris on uphill slopes, UL vastus lateralis on +6° and +9°, and soleus and tibialis anterior on a +9° slope compared to a passive-elastic prosthesis. Differences in leg muscle activity for people with TTA using a passive-elastic versus stance-phase powered prosthesis do not clearly explain differences in metabolic cost during walking on level ground and slopes.

Enhancement of Composting Methods in Solid Waste Management

The most pressing problem faced by any city center in India nowadays is Municipal Solid Waste Management (MSWM). Rapid urbanization and converting life have caused the era of massive amounts of garbage and waste within the city regions, so much so, over the last few years, just the managing this Municipal Solid Waste (MSW) has assumed the share of a primary organizational, economic and environmental task. Despite MSWM being a chief task of the local governments, normally accounting for a massive part of the municipal budget - about 20% to 50%, the Urban Local Bodies (ULBS) are not able to offer effective services. Most of the ULBs do now not even have dependable MSW generation estimates. Unfortunate fallout of rapid urbanization without good enough infrastructure backup is that during all Indian cities/cities, disposal of waste is carried out indiscriminately, main to stray animal menace, clogged drains and unfold of diseases. The procedure of collection, transportation, and disposal of MSW is not complete in a maximum of the towns/cities with rubbish thousands final unattended till the severity reaches unmanageable proportions. Also, the high organic content material of Indian MSW, compounded through the recent, and humid tropical weather results in the rapid decomposition of the uncollected waste and is an ever-present health risk. Municipal waste that is improperly disposed of has a severe and dangerous effect on a wide range of areas. Along with waste discarded close to rivers, lakes, and streams, trash dumped in the street or in open areas poses a threat to public health. Delivers contaminated water. When the trash is burned outside instead of being properly disposed of, pollutants are produced and hazardous gases are released into the atmosphere. Throwing no biodegradable items down open drains causes them to enter the sewer system, blocking pipes and harming the infrastructure. The risks associated with the disposal of untreated medical and commercial waste are increased by the release of pathogens and poisonous substances, which represent a serious threat not only to human life but also to that of plants and animals. The effects of trash thrown in the area go beyond just being an eyesore; entire landscapes are destroyed, and certain habitats for flora and fauna are lost. All of these issues are commonplace in India, where tremendous portions of strong waste remain uncollected within the streets, along side primary roads, in empty plots of land, on downhill slopes, and in illegal dumps.

Spatial variation in bicycling risk based on crowdsourced safety data

Bicycling‐related injury data are difficult to obtain from official reports, which capture only about 20% of crashes and often lack coordinates, injury outcomes, and narratives needed for understanding where and why incidents occurred. Crowdsourced data on bicycling safety provides new opportunities for the study of bicycling injury and risk. Our goal was to quantify factors that influence the spatial variation in unsafe bicycling across a city, based on self‐reports of bicycling incidents. To meet this goal, we leveraged BikeMaps.org, a global tool for reporting bicycling safety incidents, drawing on data from Metro Vancouver. We summarized incident conditions that led to injury, developed a model to identify predictors of injury using random forest regression, and mapped bicycling incident hot spots. Our results demonstrate that injuries from bicycling incidents are associated with older and younger bicyclists, downhill slopes, parked cars, recreation and weekend rides, falls, and single bicycle incidents with infrastructure, roads, and railroads. The broad range of incidents reported to BikeMaps.org allows us to add evidence that falls and single bicycle collisions are major causes of injury. Also, we demonstrate the value of attributing safety hot spots with contextual details to identify infrastructure interventions that can reduce injury for bicyclists.

Walking on Mild Slopes and Altering Arm Swing Each Induce Specific Strategies in Healthy Young Adults.

Slopes are present in everyday environments and require specific postural strategies for successful navigation; different arm strategies may be used to manage external perturbations while walking. It has yet to be determined what impact arm swing has on postural strategies and gait stability during sloped walking. We investigated the potentially interacting effects of surface slope and arm motion on gait stability and postural strategies in healthy young adults. We tested 15 healthy adults, using the CAREN-Extended system to simulate a rolling-hills environment which imparted both incline (uphill) and decline (downhill) slopes (± 3°). This protocol was completed under three imposed arm swing conditions: held, normal, active. Spatiotemporal gait parameters, mediolateral margin of stability, and postural kinematics in anteroposterior (AP), mediolateral (ML), and vertical (VT) directions were assessed. Main effects of conditions and interactions were evaluated by 2-way repeated measures analysis of variance. Our results showed no interactions between arm swing and slope; however, we found main effects of arm swing and main effects of slope. As expected, uphill and downhill sections of the rolling-hills yielded opposite stepping and postural strategies compared to level walking, and active and held arm swings led to opposite postural strategies compared to normal arm swing. Arm swing effects were consistent across slope conditions. Walking with arms held decreased gait speed, indicating a level of caution, but maintained stability comparable to that of walking with normal arm swing. Active arm swing increased both step width variability and ML-MoS during downhill sections. Alternately, ML-MoS was larger with increased step width and double support time during uphill sections compared to level, which demonstrates that distinct base of support strategies are used to manage arm swing compared to slope. The variability of the rolling-hills also required proactive base of support changes despite the mild slopes to maintain balance.

Experimental Investigation on Traction, Mobility, and Energy Usage of a Tracked Autonomous Ground Vehicle on a Sloped Soil Bin

HighlightsLaying the groundwork for AGV mobility models for high slope terrain operations.AGV drawbar pull performance was evaluated on a level terrain, uphill, and downhill slopes up to 18° on a soil bin.AGV generates the optimum power efficiency with enough drawbar pull to perform a range of agricultural operations on uphill and downhill slopes up to 18°.Explored the suitability and established the boundary conditions of small size ground vehicles on the high slope farming.Generated sloped traction data would empower the multi-AGV system on sloped terrain.Abstract. Excessive steepness of grasslands, hills, or uneven terrain presents difficulties for farming with large conventional equipment. Therefore, a fleet of Autonomous Ground Vehicles (AGV) is proposed to perform primary agricultural operations on high sloped hills or terrain. However, it is imperative to understand how an individual AGV functions on sloping terrain under varying load and speed. Hence, this study aims to investigate the traction, mobility, and energy consumption characteristics of AGV on a sloped soil bin environment. A drawbar pull performance of the prototype AGV was evaluated on a level terrain and variable slope of 10° and 18°, both uphill and downhill, at varying drawbar pull (P) and AGV speed. The AGV’s performance metrics include power efficiency (PE), travel reduction (TR), and power number (PN) which relates to AGV’s traction, mobility, and energy usage, respectively. The AGV generated drawbar pull equivalent to its weight only on downhill run for reduced PE. On a level terrain (0°), the peak PE was 0.20 and was found to be 108.3% and 328.6% higher on 10° and 18° downhill run than uphill with 55.5% and 133% increase in drawbar pull, respectively. Both applied drawbar pull and uphill operation caused the AGV’s TR. The TR, corresponding to a peak PE, increased from 10% to 30%, respectively, on 0° and both 10° and 18° uphill. The optimum values of power number ranged from 2 to 4. The AGV delivers the optimum PE and generates enough drawbar pull with an optimum TR to perform a range of agricultural operations on a slope up to 18°. This study explored the suitability and established the boundary conditions of small size ground vehicles for high-sloped farming. Besides this, the study also aims to generate an AGV’s slope traction database to optimize its control variables, design optimization, and develop a mobility model for sloped terrain. Keywords: Drawbar pull, Ground vehicle, Multi-AGV fleet, Power efficiency, Slope, Travel reduction.

Design, Fabrication, and Experimental Investigation of Screw Auger Type Feed Mechanism for a Robotic Wheat Drill

Highlights An auger-type feed mechanism was designed for a robotic wheat drill, and a laboratory investigation was carried out. To avoid seed blockage, the recommended screw auger pitch must be at least 150% of the maximum seed dimension. The performance of the feed mechanism was influenced by auger speed, vibration, and slope. This study delivered a bulk feed mechanism for wheat drilling, which can be easily scaled and adopted by small autonomous vehicles or mobile robots. Abstract. Cultivating the arable, highly sloped hills and uneven terrain is challenging and unsafe with large agricultural machines. Therefore, a fleet of small autonomous ground vehicles (AGVs) was proposed to farm sloped or uneven terrain. The fleets need a robotic grain drill to operate on varying slopes, and the success of the fleet depends on the performance of the robotic seeder or grain drill. The feed mechanism is the heart of the seeder, and its design and performance influence the plant population and crop yield. In this study, we designed and fabricated an auger-type feed mechanism for robotic wheat drilling. Feed mechanisms with augers having three different pitches were developed as per the ASABE standards. The developed feed mechanism was investigated in a laboratory setup for flow rate and flow uniformity in accordance with ISO standards. The predictor variables were auger type (pitch), auger rotational speed, vibration, and slope. The auger flow rate for flat slopes was a linear function of auger speed and varied from 30 g/min to 170 g/min. The coefficient of variation (CV) for the flow rate ranged from 2% to 10%. The CV was within acceptable limits, which was an excellent indicator of the bulk feed mechanism's flow uniformity. The performance of the feed mechanism was influenced by vibration and slope. However, the auger flow rate remained constant for vibration frequencies of 0, 6, and 14 Hz, suggesting that the feed mechanism was vibration-proof and could tolerate the vibration frequency up to 14 Hz. The flat, downhill (descending), and uphill (ascending) slope levels did not affect the feed mechanism performance. However, the side slopes (right and left slope) significantly affected the feed mechanism flow rate but did not affect the flow uniformity. The study also developed a feed mechanism for a sloped-ground prototype seeder, which can be easily scaled and adopted by small autonomous vehicles or mobile robots. Keywords: Flow rate, Flow uniformity, Multi-robot, Robotic seed drill, Screw auger, Seed rate.

GIS-based multi-criteria modelling of flood risk susceptibility in Port Louis, Mauritius: Towards resilient flood management

Economic growth and population expansion in Mauritius have driven unprecedented rates of development. Most notably, increased urbanization of flood-prone regions has exacerbated challenges around resilience and vulnerability to recurrent flooding. We implement a multi-criteria model consisting of a physical-oriented, a social-oriented and an economic-oriented scenario to identify highly vulnerable sites to flooding in the capital city, Port Louis. Social, technical, economic and legal perspectives are incorporated to propose comprehensive flood management strategies. The aim is to minimize the physical impacts of floods while also addressing the broader social and economic risks. Location-based flood management strategies are thereafter proposed to increase the resilience of the city to flooding. Measures include, inter alia, the construction of an underground stormwater storage tank at Champ de Mars, establishment of flood refugee camps at Vallée Pitot and Cité La Cure, reviewing building regulations and urban planning, replacement of the Caudan Underpass by an Overhead Bridge, green renaturing of rivers in downstream areas, construction of a retention pond on the downhill slope of the mountain at Bell Village, and the setting up of a diversion tunnel linking St Louis River to Grand River North West. The approach adopted will allow an understanding of the geography of flooding in Port Louis and support management decisions for limiting its impacts.