The purpose of this thesis is to, on Volvo Truck’s account, look at a new concept for the construction ingress used on construction vehicles which have a higher ground clearance than ordinary trucks. The high ground clearance makes it hard for the driver to reach the first instep and therefore a construction ingress is assembled below the stationary insteps. It is designed in a way that avoids damage if colliding with objects. The present construction ingress used is too expensive, too complex and a bit unsteady to climb on. There is also a new construction vehicle being developed and the old ingress might not fit the new truck. The concept generation is carried out using systematic concept development. There are many demands and requests for the ingress and these are summarized in a design criterion list. All wished-for properties can not be fulfilled for the simplest ingress designs since they conflict with each other, for example flexibility and stability. The concepts that are generated are evaluated and selected through different matrices until one concept is found to be the most promising. Different designs of this concept are discussed and one is chosen as the most suitable. The chosen concept design is already used by at least two competitors and that confirms its suitability. The detailed design presented is only a suggestion for a new construction ingress. Before manufacturing the design needs to be analysed more accurately and the strength, material and cost need to be optimized. The analyses made in the project only show that the design is realistic and that it is worth further work. The final design is promising since it is stable to use, consists of only a few simple parts and will be cheap to manufacture.

Local communities, individuals, visitors, and special interest groups are often called upon to participate in the decision making processes of the National Park Service (NPS). Cape Hatteras National Seashore (CAHA) engaged in a Negotiated Rulemaking process to create an Off Road Vehicle Management Rule. The rulemaking process involved park stakeholders working with the NPS as a Negotiated Rulemaking Advisory Committee with the goal of creating an Off Road Vehicle Management Rule for CAHA. This dissertation used Senecah's practical theory Trinity of Voice to evaluate CAHA's negotiated rulemaking process. Interviews with park staff and negotiated rulemaking participants provided information about the presence of the grammars of TOV in this decision making process. This dissertation described the affects of negotiated rulemaking on the perceptions of participants towards the park resources and management of the national seashore. The effect of the negotiated rulemaking process was an increase in the knowledge of participants about the decision making process employed by the NPS. In general, participants also developed a stronger relationship with park management. This research suggests critical dimensions for achieving widespread social legitimacy through meaningful public involvement in decision making.

<p>The purpose of this thesis is to, on Volvo Truck’s account, look at a new concept for the construction ingress used on construction vehicles which have a higher ground clearance than ordinary trucks. The high ground clearance makes it hard for the driver to reach the first instep and therefore a construction ingress is assembled below the stationary insteps. It is designed in a way that avoids damage if colliding with objects.</p><p>The present construction ingress used is too expensive, too complex and a bit unsteady to climb on. There is also a new construction vehicle being developed and the old ingress might not fit the new truck.</p><p>The concept generation is carried out using systematic concept development. There are many demands and requests for the ingress and these are summarized in a design criterion list. All wished-for properties can not be fulfilled for the simplest ingress designs since they conflict with each other, for example flexibility and stability.</p><p>The concepts that are generated are evaluated and selected through different matrices until one concept is found to be the most promising. Different designs of this concept are discussed and one is chosen as the most suitable. The chosen concept design is already used by at least two competitors and that confirms its suitability.</p><p>The detailed design presented is only a suggestion for a new construction ingress. Before manufacturing the design needs to be analysed more accurately and the strength, material and cost need to be optimized. The analyses made in the project only show that the design is realistic and that it is worth further work. The final design is promising since it is stable to use, consists of only a few simple parts and will be cheap to manufacture.</p>

Normal ageing is associated with decline in visual, cognitive, and physical functioning, with concurrent increases in the incidence of chronic medical conditions, including cognitive disorders. Determining when age-related changes have adversely affected a person’s ability to drive safely is a complex task, particularly when cognitive disorders such as mild cognitive impairment and dementia are present. The aim of this research was to assess the utility of a number of off-road measures in predicting Pass and Fail outcomes for older drivers on a blinded on-road driving assessment with a driving specialist occupational therapist and a driving instructor, which is considered the ‘gold standard’ measure of driving ability. The off-road measures included standardized cognitive tests, computerized sensory-motor & cognitive tests, medical conditions, and personality measures. The research project comprised three studies. In Study 1 (Healthy Older Drivers study), 60 drivers with no diagnosed cognitive disorder (‘cognitively-unimpaired’), aged 70-84 years (mean age 76.7, 50% male), completed standard cognitive tests, computerized sensory-motor and cognitive tests (SMCTests™), and measures of personality. Results were used to form classification models for on-road assessment Pass and Fail outcome. Sixteen participants failed the on-road assessment. A backwards stepwise binary logistic regression model selected a measure of executive function and a computerized measure of visuomotor planning and coordination as the best predictors. Following leave-one-out cross-validation, this model was estimated to correctly predict 60% of an independent group of cognitively-unimpaired older drivers into on-road Pass and Fail groups. In Study 2 (Healthy Driver Follow-up study), 56 participants from the Healthy Older Drivers study were followed for 24 months using annual telephone interviews to assess driving behaviour, driving attitudes, medical conditions, and the occurrence of crashes and receipt of traffic offences. Official data regarding crashes and traffic offences were also obtained. The aim was to determine whether either the on-road Pass/Fail classification or the off-road measures could predict subsequent crashes and offences. Failing the on-road assessment was not associated with higher crash or offence rates and there were only two baseline measures that predicted crashes or offences (i.e., distance driven at baseline testing and, paradoxically, a lower error score on a measure of visuomotor planning and coordination). However, drivers who reported more distress associated with their medical condition(s) were more likely to have had a crash or offence at 24 months. The outcomes of the Healthy Older Drivers and Healthy Driver Follow-up studies suggest that there is little value in off-road or on-road assessment of cognitively-unimpaired older drivers due to the weak relationship with future negative driving outcomes. However, distress associated with medical conditions may be a useful measure. Study 3 (Dementia and Driving study) recruited a sample of 60 driving assessment centre referrals with mild cognitive impairment or Alzheimer’s dementia. These participants, aged 58-92 years (mean age 77.9, 60% male), performed a computerized battery of sensory-motor and cognitive tests and a formal blinded on-road driving assessment. A backwards stepwise binary logistic regression model selected measures of reaction time and movement speed of the upper limbs, visuomotor planning and coordination, and sustained attention. Following leave-one-out cross-validation, this model was estimated to correctly predict 68% of an independent group of drivers with mild cognitive impairment and Alzheimer’s dementia into on-road Pass and Fail groups. A subsample of 32 participants completed additional standard cognitive tests and provided information on medical conditions. A binary logistic regression model in this subsample was formed which selected measures of verbal fluency, the presence of heart disease, and a comprehensive cognitive screen. Following leave-one-out crossvalidation, this model would be expected to correctly classify 75% of an independent group of drivers with mild cognitive impairment and Alzheimer’s dementia into on-road Pass and Fail groups. The three measures in this model could be performed in around 35-50 min in a primary health setting. It is concluded that off-road and on-road assessment of older drivers with no diagnosis of cognitive or neurological disorder is an inaccurate and inefficient use of driving assessment resources, both for the prediction of on-road driving performance and for predicting future crashes and traffic offences. The Dementia and Driving study found a model comprising three measures that could be performed in a primary health setting with reasonable accuracy for correctly classifying people with mild cognitive impairment and Alzheimer’s dementia who go on to Pass and Fail an on-road driving assessment.

Starting a few decades ago, the unmanned wheeled vehicle research has drawn lately more attention, especially for off-road environment. As the demand to use electric vehicles increased, the need to conceptualize the use of electrically driven vehicles in autonomous operations became a target. That is because in addition to the fact that they are more environmentally friendly, they are also easier to control. This also gives another reason to enhance further the energy economy of those unmanned electric vehicles. Off-road vehicles research was always challenging, but in the present work the nature of the off-road land is utilized to benefit from in order to enhance the energy consumption of those vehicles. An algorithm for energy consumption optimization for electrically driven unmanned wheeled vehicles is presented. The algorithm idea is based on the fact that in off-road conditions, when the vehicle passes a ditch or a hole, the kinetic energy gained while moving downhill could be utilized to reduce the energy consumption for moving uphill if the dimensions of the ditch/hole were known a distance ahead. Two manipulated variables are evaluated: the wheels DC motors supply voltage and the DC armature current. The developed algorithm is analysed and compared to the PID speed iii controller and to the open-loop control of DC motors. The developed predictive controller achieved encouraging results compared to the PID speed control and also compared to the open-loop control. Also, the use of the DC armature current as a manipulated variable showed more noticeable improvement over using the DC input voltage. Experimental work was carried out to validate the predictive control algorithm. A mobile robot with two DC motor driven wheels was deployed to overcome a ditch-like hindrance. The experimental results verified the simulation results. A parametric study for the predictive control is conducted. The effect of changing the downhill angle and the uphill angle as well as the size of the prediction horizon on the consumed electric energy by the DC motors is addressed. The simulation results showed that, when using the proposed approach, the larger the prediction horizon, the lower the energy consumption is.

Diss. (sammanfattning) Umeå : Univ., 2009. / Härtill 4 uppsatser.

abstract: Human recreation on rangelands may negatively impact wildlife populations. Among those activities, off-road vehicle (ORV) recreation carries the potential for broad ecological consequences. A study was undertaken to assess the impacts of ORV on rodents in Arizona Uplands Sonoran Desert. Between the months of February and September 2010, rodents were trapped at 6 ORV and 6 non-ORV sites in Tonto National Forest, AZ. I hypothesized that rodent abundance and species richness are negatively affected by ORV use. Rodent abundances were estimated using capture-mark-recapture methodology. Species richness was not correlated with ORV use. Although abundance of Peromyscus eremicus and Neotoma albigula declined as ORV use increased, abundance of Dipodomys merriami increased. Abundance of Chaetodipus baileyi was not correlated with ORV use. Other factors measured were percent ground cover, percent shrub cover, and species-specific shrub cover percentages. Total shrub cover, Opuntia spp., and Parkinsonia microphylla each decreased as ORV use increased. Results suggest that ORV use negatively affects rodent habitats in Arizona Uplands Sonoran Desert, leading to declining abundance in some species. Management strategies should mitigate ORV related habitat destruction to protect vulnerable populations. / Dissertation/Thesis / M.S. Applied Biological Sciences 2012

Die doel van die navorsing wat in hierdie verslag bespreek word, was om ondersoek in te stel na die omrolgedrag van veldvoertuie. Die studie is gedoen deur gebruik te maak van ʼn Land Rover Defender 110 sport nutsvoertuig as eksperimentele voertuig, en ADAMS View as sagteware pakket Die sogenaamde “vishoektoets” is met die basislynvoertuig uitgevoer. Daar is korrelasie verkry tussen die data wat tydens die toetse opgeneem is, en ʼn volledige drie-dimensionele model van die voertuig in ADAMS View. Die basislynsuspensie op die voertuig is vervolgens vervang met ʼn vier toestand semi-aktiewe hidropneumatiese suspensiestelsel of 4S4. Die toetse is herhaal, en korrelasie verkry tussen die toetsdata en die rekenaarmodel. Die rekenaarmodel, met die basislyn suspensiekarakteristieke vervang met die hidropneumatiese suspensiekarakteristieke, is teen hierdie toetsdata geverifieer. Die rekenaarmodel is na korrelasie gebruik om te bepaal watter veer- en demperstellings die effektiefste sal wees om omrol te voorkom. Verder is die model ook gebruik om die effek van rithoogteverlaging op omrolgeneigdheid te bepaal. Die hoeveelheid wat die wiele oplig, is as norm vir omrolgeneigdheid gebruik. Ander parameters, soos giersnelheid, rolsnelheid en rolhoek is ook ondersoek. Uit die studie is dit duidelik dat die 4S4, met die moontlikheid van verstelling aan rithoogte, sinvol aangewend kan word om omrolgeneigdheid te verminder. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2008. / Mechanical and Aeronautical Engineering / unrestricted

The designers of heavy, off-road vehicle suspension systems face unique challenges. The ride comfort versus handling compromise in these vehicles has been frequently investigated using mathematical optimisation. Further challenges exist due to the large variations in vehicle sprung mass. The suspension system must provide adequate isolation from road load inputs throughout its payload operating range. This is imperative if good vehicle structural life is to be ensured. A passive suspension system can only provide optimal isolation at a single payload. The designer of such a suspension system must therefore make a compromise between designing for a fully-laden or unladen payload state. This work deals with suspension optimisation for vehicle structural life. The work mainly addresses two questions: 1) What are the suspension characteristics required to ensure optimal isolation of the vehicle structure from road loads? and 2) If such optimal suspension characteristics can be found, how sensitive are they to changes in vehicle payload? The study aims to answer these questions by examining a Land Rover Defender 110 as case study. An experimentally validated mathematical model of the test vehicle is constructed for the use in sensitivity studies. Mathematical optimisation is performed using the model in order to find the suspension characteristics for optimal structural life of the vehicle under consideration. Sensitivity studies are conducted to determine the robustness of the optimal characteristics and their sensitivity to vehicle payload variation. Recommendations are made for suspension characteristic selection for optimal structural life. AFRIKAANS : Ontwerpers van swaar, veldvoertuig suspensie stelsels staar unieke uitdagings in die gesig. Die ritgemak teenoor hantering kompromie in hierdie voertuie is reeds telkemale ondersoek, ook met wiskundige optimering. Verdere uitdagings bestaan as gevolg van die groot veranderinge in geveerde massa by hierdie voertuie. Die suspensiestelsel moet gepaste isolasie van pad insette oor `n wye reeks van bedryfstoestande lewer. Dit is veral belangrik indien daar verseker wil word dat die voertuig goeie struktuurleeftyd het. `n Passiewe suspensiestelsel kan egter slegs optimale isolasie by `n enkele vragtoestand lewer. Die ontwerper van `n passiewe suspensie stelsel moet dus `n kompromie aangaan tussen ontwerp vir `n vol of leë vragtoestand. Hierdie studie handel oor suspensie optimering vir struktuur leeftyd. Die werk spreek hoofsaaklik twee vraagstukke aan: 1) Watter suspensie karakteristieke word benodig om die voertuig struktuur optimaal van padinsette te isoleer? en 2) Indien sulke optimale karakteristieke gevind kan word, wat is hulle sensitiwiteit vir veranderinge in voertuig vrag? Die studie mik om hierdie vraagstukke aan te spreek deur ondersoeke op `n Land Rover Defender 110 toetsvoertuig. `n Eksperimenteel gevalideerde, wiskundige model van die toetsvoertuig word saamgestel met die oog op sensitiwiteitstudies. Wiskundige optimering word met die model uitgevoer om sodoende die suspensie karakteristieke vir optimale struktuurleeftyd vir die betrokke toetsvoertuig te bepaal. Sensitiwiteitsanalises word gedoen om die robuustheid van die optimale karakteristieke, met betrekking tot veranderinge in voertuig vrag, vas te stel. Aanbevelings word gemaak oor die keuse van suspensie karakteristieke vir optimale struktuur leeftyd. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Mechanical and Aeronautical Engineering / unrestricted

The steering arrangement of a 6x6 off-road military vehicle was investigated, with the aim to determine if a variable steering ratio between the first and second steering axle of the vehicle will make an improvement in the steady and transient state handling of the vehicle. Low speed manoeuvring was evaluated, comparing the vehicle steering geometry with Ackerman geometry. For steady state handling, a bicycle model was developed, and constant radius simulations at various track radii, vehicle speeds and steering ratios (ratio between the first and second steering axle) was performed. For transient dynamic simulations, a mathematical model was developed that included a simple driver model to steer the vehicle through a single lane change, again at various speeds and steering ratios. The vehicle was instrumented, and actual constant radii tests, as well as single lane change tests were performed. The measurements enabled the comparison of simulated and measured results. Although basic mathematical models were used, acceptable correlation was obtained for both steady state and transient dynamic behaviour. The results indicated that for this specific vehicle geometry, where the centre of mass is above the second axle, no marked improvement would be obtained by implementing a variable ratio steering system. The mathematical model was changed to simulate a vehicle with longer wheelbase and different centre of mass. With the new geometry, theoretical slip angles (and therefore tire wear) reductions were more noticeable It was concluded that a variable ratio system between the front and second axle would not be an economically viable improvement for this vehicle, since the improvement achieved will not warrant the additional cost and complexity added to the vehicle. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / MEng / unrestricted