36 research outputs found

    Sales and Title and the Proposed Code

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    Electric powertrain faults that could occur during normal driving can affect the dynamic behaviour of the vehicle and might result in significant course deviations. The severity depends both on the characteristics of the fault itself as well as on how sensitive the vehicle reacts to this type of fault. In this work, a sensitivity study is conducted on the effects of vehicle design parameters, such as geometries and tyre characteristics, and fault characteristics. The vehicle specifications are based on three different parameter sets representing a small city car, a medium-sized sedan and a large passenger car. The evaluation criteria cover the main motions of the vehicle, i.e. longitudinal velocity difference, lateral offset and side slip angle on the rear axle as indicator of the directional stability. A design of experiments approach is applied and the influence on the course deviation is analysed for each studied parameter separately and for all first order combinations. Vehicle parameters of high sensitivity have been found for each criterion. The mass factor is highly relevant for all three motions, while the additional factors wheel base, track width, yaw inertia and vehicle velocity are mainly influencing the lateral and the yaw motion. Changes in the tyre parameters are in general less significant than the vehicle parameters. Among the tyre parameters, the stiffness factor of the tyres on the rear axle has the major influence resulting in a reduction of the course deviation for a stiffer tyre. The fault amplitude is an important fault parameter, together with the fault starting gradient and number of wheels with fault. In this study, it was found that a larger vehicle representing a SUV is more sensitive to these types of faults. To conclude, the result of an electric powertrain fault can cause significant course deviations for all three vehicle types studied.QC 20140909</p

    Autonomous corner modules as an enabler for new vehicle chassis solutions

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    Demands for new functions and refined attributes in vehicle dynamics areleading to more complex and more expensive chassis design. To overcome this, there hasbeen increasing interest in a novel chassis design that could be reused in the developmentprocess for new vehicle platforms and mainly allow functions to be regulated by software.The Autonomous Corner Module (ACM) was invented at Volvo Car Corporation (VCC) in1998. The invention is based upon actively controlled functions and distributed actuation. Themain idea is that the ACM should enable individual control of the functions of each wheel;propulsion/braking, alignment/steering and vertical wheel load. This is done by using hubmotorsand by replacing the lower control arm of a suspension with two linear actuators,allowing them to control steering and camber simultaneously. Along with activespring/damper and wheel motors, these modules are able to individually control each wheel\u27ssteering, camber, suspension and spin velocity. This provides the opportunity to replacemechanical drive, braking, steering and suspension with distributed wheel functions which, inturn, enable new vehicle architecture and design.The aim of this paper is to present the vehicle dynamic potential of the ACM solution, bydescribing its possible uses and relating them to previous research findings. Associated worksuggests chassis solutions where different fractions of the functions of the ACM capabilityhave been used to achieve benefits in vehicle dynamics. For instance, ideas on how to useactive camber control have been presented. Other studies have reported well-knownadvantages, such as, good transient yaw control from in-wheel motor propulsion and stablechassis behaviour from four-wheel steering, when affected by side wind. However, thistechnology also presents challenges. One example is how to control the relatively largeunsprung mass that occurs due to the extra weight from the in-wheel motor. The negativeinfluence from this source can be reduced by using active control of vertical forces. Theimplementation of ACM, or similar technologies, requires a well-structured hierarchy andcontrol strategy. Associated work suggests methods for chassis control, where tyre forces canbe individually distributed from a vehicle path description. The associated workpredominately indicates that the ACM introduces new opportunities and shows itself to be apromising enabler for vehicle dynamic functions

    The Alaska Workers’ Compensation Law: Fact-Finding, Appellate Review, and the Presumption of Compensability

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    This paper presents a fault handling strategy for electric vehicles with in-wheel motors. The ap-plied control algorithm is based on tyre-force allocation. One complex tyre-force allocation meth-od, which requires non-linear optimization, as well as a simpler tyre force allocation method are developed and applied. A comparison between them is conducted and evaluated against a standard reference vehicle with an Electronic Stability Control (ESC) algorithm. The faults in consideration are electrical faults that can arise in in-wheel motors of permanent-magnet type. The results show for both tyre-force allocation methods an improved re-allocation after a severe fault and thus re-sults in an improved state trajectory recovery. Thereby the proposed fault handling strategy be-comes an important component to improve system dependability and secure vehicle safety.QC 20130611</p

    Energy efficient cornering using over-actuation

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    This work deals with utilisation of active steering and propulsion on individual wheels in order to improve a vehicle’s energy efficiency during a double lane change manoeuvre at moderate speeds. Through numerical optimisation, solutions have been found for how wheel steering angles and propulsion torques should be used in order to minimise the energy consumed by the vehicle travelling through the manoeuvre. The results show that, for the studied vehicle, the energy consumption due to cornering resistance can be reduced by approximately 10 % compared to a standard vehicle configuration. Based on the optimisation study, simplified algorithms to control wheel steering angles and propulsion torques that results in more energy efficient cornering are proposed. These algorithms are evaluated in a simulation study that includes a path tracking driver model. Based on a combined rear axle steering and torque vectoring control an improvement of 6-8 % of the energy consumption due to cornering was found. The results indicate that in order to improve energy efficiency for a vehicle driving in a non-safety-critical cornering situation the force distribution should be shifted towards the front wheels

    Оценка эффективности фармакотерапии и приверженности к лечению у пациентов с бронхиальной астмой с помощью онлайн-опросников

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    АСТМА БРОНХИАЛЬНАЯ /ЛЕК ТЕРЛЕГКИХ БОЛЕЗНИ ОБСТРУКТИВНЫЕКОМПЛАЕНС БОЛЬНОГО С РЕЖИМОМ ЛЕЧЕНИЯБОЛЬНОГО СОГЛАСИЕ С РЕЖИМОМ ЛЕЧЕНИЯБОЛЬНОГО ПОДЧИНЕНИЕ РЕЖИМУЛЕКАРСТВЕННАЯ ТЕРАПИЯФАРМАКОТЕРАПИЯАНКЕТИРОВАНИЕОНЛАЙН-ОПРОС

    Energy Efficiency Analyses of a Vehicle in Modal and Transient Driving Cycles including Longitudinal and Vertical Dynamics

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    The growing concerns about the environmental issues caused by vehicles and a strive forbetter fuel economy, urge the legislators to introduce conservative regulations on vehicletesting and homologation procedures. To have accurate evaluations, driving cycles thatcan sufficiently describe the vehicles’ conditions experienced during driving is a prerequisite.In current driving cycles there are still some issues which are disregarded. The aim ofthe presented work is to study the contribution of chassis and vehicle dynamics settings ontyre rolling loss in comparison with the original assumptions made in the NEDC, FTP andHWFET driving cycles. A half-car model including a semi-physical explicit tyre model tosimulate the rolling loss is proposed. For the chosen vehicle and tyre characteristics,depending on the specific chassis settings and considered driving cycle, considerable differenceup to 7% was observed between the energy consumption of the proposed- and conventionalapproach. The current work aims to provide the legislators with a betterinsight into the real effects of chassis and vehicle dynamics during the certification processto further improve the test related procedures required for homologation such as generationof road load curves. I.e., the aim is not to provide a new homologation process, sincethere are also other effects such as road roughness and tyre temperature that need to beconsidered. The results are also of interest for the vehicle manufacturers for further considerationsduring test preparation as well as in the development phase in order to reduce theenvironmental impacts.QC 20170529</p

    Modelling and experimental evaluation of driver behaviour during single wheel hub motor failures

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    A failure-sensitive driver model has been developed in the research study presented in this paper. The model is based on measurements of human responses to dierent failure conditions inuencing the vehicle directional stability in a moving-base driving simulator. The measurements were made in a previous experimental study where test subjects were exposed to three sudden failure conditions that required adequate corrective measures to maintain the vehicle control and regain the planned trajectory. A common driver model and a failure-sensitive driver model have been compared, and results for the latter agree well with the measured data. The proposed failure-sensitive driver model is capable of maintaining the vehicle control and regaining the planned trajectory similarly to the way in which humans achieved this during a wheel hub motor failure in one of the rear wheels.QC 20150520</p

    Evaluation of Combined Energy-Efficientand Stability Strategies Utilising DirectYaw Moment Control

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    For sustainability reasons it is important to reduce energyconsumption during driving. One contributionto energysavings is by AQ1using proper wheel torque distributions during manoeuvring. An activeenergy-efficient direct yaw moment control (DYC) for electric vehicleshas previously been proposed by the authors, taking the motor efficiencymap into consideration. The results show a potential for reduced energylosses during driving, but it might result in stabilityproblems duringsafety-critical maneuvres. In this work, consequences on stability dueto this proposed energy efficient DYC is explored. Also an approachcombining DYC both energy-efficiency and stability is proposed. Thesimulation results show that for the studied case the combination ofDYC for energy-efficiency and stability can have an potential to bothkeep the vehicle safe and save considerable percentage of energy duringboth non safety-critical and safety-critical driving manoeuvres.QC 20200224</p
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