On a Development of Two Wheeled Vehicle Riding Simulator

<div class="section abstract"><div class="htmlview paragraph">The steering system of a 3-wheeler vehicle comprises a single column steering tube. The steering inclination at handle bar end is converted to wheel slip or inclination by the steering column. A compromise in either ride or handling is considered in the functional requirement of the 3-wheeler vehicle.</div><div class="htmlview paragraph">The 3- wheeler vehicle under study is designed for ride comfort and the handling levels are compromised. Variants of the vehicle under study are meant for public passenger transport requirements. Drivers' ride comfort is considered as the primary functional requirement during design and driver's steering fatigue is not given importance. For the comfort of driver, steering effort has to be less without compromise in handling characteristics. The driver of this type of vehicle drives the vehicle for 15-18 hours a day. Driver's feedback suggests high steering effort as a human fatigue failure mode and also a cause of shoulder pain.</div><div class="htmlview paragraph">In the present work, a DC motor assisted steering mechanism with an electronic control module has been designed. This improves the handling of the vehicle and reduces the static steering effort. Steering effort of the vehicle is experimentally determined in a test track for static maneuvering conditions. A look up table reference is used for programming the control module and to control the DC motor for various operating steering angle. The tests are also carried out in driver alone and gross vehicle weight conditions. The test results suggest reduce of steering effort levels for the vehicle studied.</div></div>

<div class="htmlview paragraph">This paper describes methods, based on applied mechanics and simplified operational analysis, for the evaluation of various vehicle concepts considered feasible for lunar surface exploration, and shows processes through which means of locomotion may be optimized. Although little is known of the physico-geometrical properties of the lunar surface which relate to vehicle mobility, by assuming a plausible spectrum of properties, valuable preliminary information can be derived with respect to the probable effectiveness of various feasible lunar vehicle concepts.</div> <div class="htmlview paragraph">Wheeled, tracked, screw-propelled, and walking vehicles are analyzed and their probable performances compared. Indications at the present time are that wheeled vehicles may probably best suit the purpose of lunar exploration.</div>

<div class="htmlview paragraph">SAND, mud, and snow can present obstacles to military vehicles which are almost as tough to negotiate as manmade traps. With proper vehicle design these former obstacles can be made to become insignificant.</div> <div class="htmlview paragraph">Cross-country operation is affected by two vehicle characteristics, flotation and traction. What is adequate flotation on one terrain is inadequate on another, and this same statement can be applied to traction. With track-laying vehicles, these factors are rather absolute, but with wheeled vehicles, inflation and tire stiffness may be important.</div> <div class="htmlview paragraph">One other important thing affecting wheeled vehicles is the number of wheels which are driving. Wherever the coefficient of traction is low it is imperative that every wheel contacting the ground be able to contribute its share of forward tractive effort.</div> <div class="htmlview paragraph">All these things add up to say that the only connection between the engine and the forward movement of a vehicle is the tires or tracks on which that vehicle rests, and it is for this reason that the principles of flotation and traction must be adhered to or cross-country operation may be impossible.</div>

<div class="section abstract"><div class="htmlview paragraph">The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity (it is defined as the distance traveled divided by the time elapsed), and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-toweight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical.</div><div class="htmlview paragraph">In this investigation we evaluate the effectiveness of the main methods of power distribution between the drive wheels of the multipurpose wheeled vehicles: disabling of drive axles, blocking of cross-axle and inter-axle differentials, a slowdown of slipping wheels.</div><div class="htmlview paragraph">It was revealed that the transmission of a promising multipurpose wheeled vehicle has to be modernized in the following ways: 1) all-wheel drive with the rational value of the gear ratio of inter-axle differential; 2) realization of the possibility of periodic shutdown of the drive axles when road conditions are good, or turning on the additional driving axles of the trailer when the road conditions require significant drive forces and torques; 3) providing of limited excess capacity of power unit by reducing the fuel supply or applying braking torque to the slipping wheels; 4) providing of rigid kinematic connection in the movement process with compensation of the kinematic mismatch by adjusting of air pressure in the tires.</div><div class="htmlview paragraph">At present, the effectiveness of the proposed methods of power distribution has been investigated in different extent. Thus, there arises the problem of the complex evaluation of the effectiveness of methods of the power distribution between the drive wheels of the multi-purpose wheeled vehicle. This investigation is devoted to this problem.</div></div>

<div class="htmlview paragraph">Recent years have seen an increased emphasis on producing automobiles with a ‘performance’ image, and a corresponding level of performance capability. Greatly increased engine power and cornering ability naturally lead to the need for increased braking capability. With more and more vehicle programs developing, validating and advertising their performance at the racetrack, the need arises for objective means of measuring brake performance and differentiating between brake system configurations under these driving conditions.</div> <div class="htmlview paragraph">One of the greatest challenges of measuring brake performance during racetrack driving conditions is coping with the wide range of braking conditions and driving styles incurred. Rapid brake applies and releases, and brake modulation make it very difficult to get a meaningful measure of brake output. Furthermore, a steadfast desire to maintain brake cooling airflow as design representative as possible, and to insure the safe operation of the test vehicle prevents the use of torque transducer wheels for directly measuring brake torque. Racetrack operation also prevents the use of any other sort of measuring device requiring the use of slip rings protruding from the center of the wheels of the test vehicle for this same reason.</div> <div class="htmlview paragraph">To address these issues, measurements were made of vehicle deceleration and brake system pressure over the course of multiple laps of a closed-loop racetrack. Vehicle deceleration was related to brake system pressure with a term called ‘Brake Hydraulic Pressure Deceleration Gain (BHPDG)’, or ‘Decel Gain’ (DG) for short. By examining how this relationship changed with brake lining temperature and over time, it was possible to detect and measure brake fade. Statistical analysis on these data allowed for data sets from different brake configurations to be compared.</div> <div class="htmlview paragraph">A method of measuring and representing apply system runout is also covered, as are methods of graphically representing the large quantity of data typically gathered during a race track event. Examples from multiple test vehicles are used to depict the occurrence of brake performance issues at the racetrack such as mechanical and temperature-related fade and apply system runout. Examples are also used to depict ‘good’ performance.</div>

<div class="htmlview paragraph">Fuel consumption depends on the automobile constructional parameters, speed and operational conditions. Since they determine the dynamic qualities as well, it is expedient to use that common dependency to find a complex solution of both problems.</div> <div class="htmlview paragraph">As it was stated in <i>Estimation of Dynamic Qualities of Undercarriage Machines</i> at ATT 2001 Conference and Exhibition in Barcelona, the assessment methods known up to now assume that the resistance with moving is a constant. The influence of loading and speed modes on the power losses is not taken into account.</div> <div class="htmlview paragraph">The paper presents methods of theoretical study on the economic qualities of a transport undercarriage machine considering the multi-factor influence of operational conditions.</div>

<div class="section abstract"><div class="htmlview paragraph">Pilot injections are normally used for the reduction of diesel engine emissions and combustion noise. Nonetheless, with a penalty on the indicated thermal efficiency. The cost is reduced by the minimization of the pilot mass, which on its counterpart increases the risk of pilot misfire. Pilot misfire can have a higher penalty on the indicated efficiency if it is not compensated adequately. This paper investigates how in-cycle closed-loop combustion control techniques can reduce the effects of pilot misfire events.</div><div class="htmlview paragraph">By closed-loop combustion control, pilot misfire can be detected and counteracted in-cycle. Two injection strategies are investigated. The first is the control of the main injection, the second includes an additional second pilot injection. Based on the in-cycle misfire diagnose, two architectures are investigated. The first uses a cycle-to-cycle controller to set the main injection under each scenario. The second is a fully in-cycle controller with feedback from predictive models. All the algorithms were tested experimentally in a Scania D13 engine.</div><div class="htmlview paragraph">The results confirmed that in-cycle closed-loop combustion control can effectively reduce the effects of pilot misfire. An error of +1.5CAD on the main SOC and −0.5bar IMEP on the engine load was reduced to 0±0.6CAD and 0±0.4bar IMEP using the cycle-to-cycle architecture. The predictive in-cycle control can further reduce the error of the main SOC to 0±0.4CAD and 0±0.2bar IMEP for the engine load. These two approaches had one degree of freedom, and therefore only one of the combustion timing parameters (SOC or CA50) was regulated successfully. With the additional degree of freedom of the second pilot injection, the misfire effects were not only reduced, but also fully counteracted.</div><div class="htmlview paragraph">The methods are limited by the time window where pilot misfire observability and controllability overlap. This is set by the injections’ separations and the respective ignition delays. The second pilot injection can be further improved by the regulation of its injection timing and duration. The results can enhance the nominal set-up optimization by including the in-cycle controllability and regulation performance in the constraints.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Vehicle dynamics encompasses a vehicle’s motion along three principal axes: longitudinal, lateral, and vertical. The vertical component is particularly susceptible to vibrational forces that can impair passenger comfort and overall performance, and the suspension system filters these vibrations. Engineers and designers conduct various studies to enhance quality and develop innovative designs in this context.</div><div class="htmlview paragraph">However, when it comes to military vehicles, this system is often treated as classified. Consequently, the proposed work aims to determine the parameters of this system for a wheeled military vehicle with four axles. To achieve this, a mathematical model is proposed utilizing the concepts of power flow and kinematic transformers through a modular system, intended to serve as the foundation for solving an inverse problem to identify these parameters.</div><div class="htmlview paragraph">This approach employs two stochastic methods, particle swarm optimization (PSO) and differential evolution (DE), and field tests to collect real data from the vehicle. Following the parameter estimation, a comparison between the numerical simulation and the actual dynamic behavior of the vehicle is proposed. Based on these tests, the system is analyzed under several proposed configurations.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Autonomous vehicles have the potential to provide mobility to individuals who experience transportation disadvantages due to the inability to drive as a result of physical, cognitive or visual limitations/impairments as well as able-bodied individuals with no/limited desire to drive. Individuals who do not have easy access to transportation have social, academic, health, and career disadvantages in comparison to their peers. Fully autonomous vehicles have the potential to offer mobility solutions to these individuals.</div><div class="htmlview paragraph">A user-centered design approach was utilized by a multidisciplinary team of engineers, human factors specialists, and designers to develop future vehicle features for a broad range of users. In-depth interviews and day-in-the-life experiences provided the team with an understanding of the needs and constraints of very different types of users including:<ul class="list disc"><li class="list-item"><div class="htmlview paragraph">a millennial with a visual impairment,</div></li><li class="list-item"><div class="htmlview paragraph">a professional in a major metropolitan area who does not want to drive yet needs to transport influential clients to meetings throughout the city,</div></li><li class="list-item"><div class="htmlview paragraph">a full-time working mom with 3 kids under the age of 12, and.</div></li><li class="list-item"><div class="htmlview paragraph">a designer who is a quadriplegic who lives as independently as possible while using a large motorized wheelchair.</div></li></ul></div><div class="htmlview paragraph">User preferences, needs, and wants are discussed for each user. Future autonomous vehicles will have vastly different metrics for user satisfaction than what exists today.</div></div>

<div class="htmlview paragraph">Cycle-resolved numerical and experimental analyses were carried out to study the dynamics of an automotive diesel injection system with a distributor-type pump during transient control phases. The investigation had the following main objectives: to assess a flexible and efficient simulation program of high-pressure fuel-injection systems in unsteady operating conditions; to examine the system response to rapid load or speed variations, regardless of the control device which may cause them. The program, based on a fast implicit numerical algorithm with second-order accuracy, was an extension of the computational code NAIS which had been previously developed and validated for stationary operating conditions. The experiments were made on a test bench usually used by industry to evaluate diesel injection equipment.</div> <div class="htmlview paragraph">A nonlinear system numerical model with two degrees of freedom, developed for the pump speed-governor, was set up and included in a library containing a variety of system component models so as to give a modular structure to the NAIS code. Comparison between computed and measured static characteristics of the governor was made in order to assess the model of this system component.</div> <div class="htmlview paragraph">Experimental tests were carried out by rapidly moving the pump control lever from its idle position to the full-load position at two constant pump speeds, in the low and high-speed range, respectively. During these transient operations pressure time-histories were gauged and simulated cycle-by-cycle in the pumping chamber and at the distribution-pipe ends. In-cycle fuel-injected quantities were also measured and computed. Results were compared and discussed.</div> <div class="htmlview paragraph">The dynamic system behavior under assigned transient load or speed phases was then theoretically analyzed by computing local-pressure, needle-lift and injection-rate time histories. Besides, experimental steady-state distributions of the injection rate and injection pressure, that is the pressure in the sac chamber, were compared to the simulation results during an acceleration phase at full load.</div>

<div class="htmlview paragraph">Submarining is a common cause of injury in severe frontal crashes. Furthermore, submarining protection may limit lap-belt designs, in that it restricts the range of usable lap-belt angles. Therefore a method to assess how close the occupant substitute is to submarining in a crash test is desirable.</div> <div class="htmlview paragraph">In this paper the hypothesis was that the maximum value of the angle, in the x-z plane, between the lap-belt and the pelvis during the time-period when the belt force exceeds 3 kN is a measure of the lap-belt slipping off the pelvis in a frontal impact. In order to obtain this angle with high precision, five mechanical sled-tests with the Hybrid-III dummy was transferred into MADYMO. In MADYMO belt slip over the dummy pelvis was modeled by means of two orthogonal, translational joints (i. e. joints with one-dimensional translation as their only degree of freedom) on the right and left Anterior Superior Iliac Spine (A.S.I.S., also called iliac crest wing) and thus bilateral and unilateral belt slip could be assessed.</div> <div class="htmlview paragraph">The results support the hypothesis. Thus a belt-to-pelvis angle of 11 degrees in the simulations corresponded to observed lap-belt slippage in the sled tests, whereas the lap-belt acted on the pelvic structures throughout those tests in which the belt-to-pelvis angle did not exceed eight degrees. Results from subsequent simulations point out belt-slack, velocity change (Δv), and initial knee angle as factors strongly related to the tendency for submarining.</div> <div class="htmlview paragraph">The conclusion is that the maximum belt-to-pelvis angle during the time-span when the lap-belt force exceeds 3 kN can be used to estimate the tendency for belt slip onto the abdomen and submarining in mathematical simulations of frontal impacts.</div>

<div class="htmlview paragraph">Emissions optimization, particularly for complex engines, relies on developing mathematical correlations or ‘Response Surface Models’ of engine outputs. There is a clear tradeoff between the complexity of the model and its usefulness for a range of optimization tasks.</div> <div class="htmlview paragraph">Several current SI engine management systems use a ‘Spark efficiency curve’ to elegantly describe the response of engine torque to spark advance using a prescribed characteristic line that is fitted to a spark sweep with only two degrees of freedom. This provides a powerful method of data reduction.</div> <div class="htmlview paragraph">A similar technique has been developed to characterize engine emissions data. A single efficiency curve with only two degrees of freedom can be used to accurately describe the response of, say, hydrocarbon emissions to spark over a wide range of engines and operating conditions. The technique offers similar data reduction advantages for engine management system developers and those optimizing engines using high DoF models. The form and application of the efficiency curves is discussed and examples of application to tasks such as engine emission optimization are discussed.</div>

<div class="htmlview paragraph">Electric Power-Assisted Steering (EPAS) is a new power steering technology that will define the future of vehicle steering. The assist of EPAS is the function of the steering wheel torque and vehicle velocity. The assist characteristic of EPAS is set by control software, which is one of the key issues of EPAS. The straight-line type assist characteristic has been used in some current EPAS products, but its influence on the steering maneuverability and road feel hasn't been explicitly studied in theory.</div> <div class="htmlview paragraph">In this paper, the straight-line type assist characteristic is analyzed theoretically. Then a whole vehicle dynamic model used to study the straight-line type assist characteristic is built with ADAMS/Car and validated with DCF (Driver Control Files) mode of ADAMS/Car. Based on the whole vehicle dynamic model, the straight-line type assist characteristic's influence on the steering maneuverability and road feel is investigated. Based on the driver's request for the ideal relationship between steering wheel torque and vehicle velocity, the vehicle speed proportional coefficient of the assist characteristic can be determined by making steering wheel torque at different vehicle lateral acceleration agree with the request of the driver at a certain velocity. The target of this paper is analyzing the influence of the straight-line type assist characteristic on the steering maneuverability and road feel, and studying how to apply simulation method to determine the straight-line type assist characteristic of EPAS, which will direct and benefit the adjustment of the assist characteristic during the road test.</div>

<div class="htmlview paragraph">This paper discusses the optimization of the traction ability of a four wheel vehicle, by reducing the friction between the wheels and the ground required to sustain the motion of the vehicle. As a consequence, this will lead to the safest driving, incurring minimum damage on the surface of the ground.</div> <div class="htmlview paragraph">A full optimization includes controlling the longitudinal (tractive) forces and the lateral forces. A control of the vertical reactions (vertical load transfer) is also considered. The control procedure is based on a “disruption motion” that is determined by a <i>geometric-static</i> analysis that does not require solving differential equations. This optimization is a viable basis for computed-torque control of electrically-driven vehicles (e.g. automated guided vehicles, electro-mobiles), and is suitable for the on-line control of any other type of vehicles.</div>

<div class="htmlview paragraph">The design of two new resilient band suspension systems are compared to show that one system is potentially superior over the other. The first design is loopwheel, developed for use on off-road military vehicles. The second design is track wheel, partially developed for use on wheelchairs.</div> <div class="htmlview paragraph">Full scale loopwheel models have demonstrated that a resilient band suspension provides much improved soft soil traction over a wheeled vehicle. Major deficiencies of this design are a high rolling resistance and a tendency to throw the band at the sprockets. These problems are not expected in a track wheel with a spring track. Moreover, a close comparison shows that track wheel has four major advantages over loopwheel; simple design (lower cost), carries more load, greater stability and lower rolling resistance.</div>