A review is presented of the one-parameter, nonsmooth bifurcations that occur in a variety of continuous-time piecewise-smooth dynamical systems. Motivated by applications, a pragmatic approach is taken to defining a discontinuity-induced bifurcation (DIB) as a nontrivial interaction of a limit set with respect to a codimension-one discontinuity boundary in phase space. Only DIBs that are local are considered, that is, bifurcations involving equilibria or a single point of boundary interaction along a limit cycle for flows. Three classes of systems are considered, involving either state jumps, jumps in the vector field, or jumps in some derivative of the vector field. A rich array of dynamics are revealed, involving the sudden creation or disappearance of attractors, jumps to chaos, bifurcation diagrams with sharp corners, and cascades of period adding. For each kind of bifurcation identified, where possible, a kind of “normal form” or discontinuity mapping (DM) is given, together with a canonical example and an application. The goal is always to explain dynamics that may be observed in simulations of systems which include friction oscillators, impact oscillators, DC-DC converters, and problems in control theory.

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Bifurcations in Nonsmooth Dynamical Systems

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Dynamics and bifurcations of nonsmooth systems: A survey

The implementations of fuel cells (FCs) in the vehicle industry have gained great attention for the last few decades owing to simple utilization, silent operation, high efficiency and modular structure. Technological advancements show that the use of FCs in electric vehicles (EVs) will increase rapidly and cause a revolution, and will be an alternative to traditional vehicles in the future. Commercial vehicles, projects and research show that work is underway to ensure that FCEVs have sufficient performance advances for their daily transportation needs. However, the lack of a detailed study that will shed light on researchers working in this field is obvious. It aims to provide a comprehensive scientific publication on the current status and future expectations to engineers and researchers interested in this field. In the current study, numerous studies have been examined in detail and added as supplementary to the bibliography. In this context, FCEVs are classified under headings of configurations, systems components, control/management, technical challenges, marketing and future aspects. First of all, FC types and electric motors are discussed in terms of their application areas, characteristic properties and operating conditions. Power converters, which are voltage regulation and motor drive topologies used in FCEVs, are detailed according to the structural frequency of use, structure, and complexity. In the next sections, control issues for converters and technical challenges are branched for FCEVs. In final section, the current status and future aspects are reported using a large number of marketing and target data.

A review and research on fuel cell electric vehicles: Topologies, power electronic converters, energy management methods, technical challenges, marketing and future aspects

Electronic stability control (ESC) is an evolution of antilock brake technology designed to help drivers maintain control of their vehicles in high-speed or sudden maneuvers and on slippery roads. Manufacturers first began equipping vehicles with ESC in the mid 1990s in Europe, and the technology appeared in other markets several years later. The wider proliferation of ESC across the vehicle fleet has allowed evaluation of its effects in real world crashes in many countries, including Japan, Germany, Sweden, France, Great Britain, and the United States. Studies have examined crash effects on different roadways, using differing analytic methods, different crash severities, and different make/model vehicles including both cars and SUVs. This paper provides a summary of those findings. Most studies find that ESC is highly effective in reducing single-vehicle crashes in cars and SUVs. Fatal single-vehicle crashes involving cars are reduced by about 30-50 percent and SUVs by 50-70 percent. Fatal rollover crashes are estimated to be about 70-90 percent lower with ESC regardless of vehicle type. A number of studies find improved effectiveness in reducing crashes when road conditions are slippery. There is little or no effect of ESC in all multi-vehicle crashes; however, there is a 17-38 percent reduction in more serious, fatal multi-vehicle crashes. Given the extraordinary benefits of ESC in preventing crashes, the implementation of ESC should be accelerated to include the full range of vehicles in both developed and developing markets.

The effectivness of electronic stability control in reducing real world crashes: a literature review

Chaos in brake squeal noise

By definition, chaotic vibrations arise from nonlinear deterministic physical systems or non-random differential or difference equations. In numerous engineering systems there exist nonlinearities ...

Nonlinear dynamics of parts in engineering systems

A method is presented for controlling the persistence of a local attractor near a grazing periodic trajectory in a piecewise smooth dynamical system in the presence of discontinuous jumps in the state associated with intersections with system discontinuities. In particular, it is shown that a discrete, linear feedback strategy may be employed to retain the existence of an attractor near the grazing trajectory, such that the deviation of the attractor from the grazing trajectory goes to zero as the system parameters approach those corresponding to grazing contact. The implementation relies on a local analysis of the near-grazing dynamics using the concept of discontinuity mappings. Numerical results are presented for a linear and a nonlinear oscillator.

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Control of near-grazing dynamics in impact oscillators

Fault-tolerant vehicle design is an emerging inter-disciplinary research domain, which is of increased importance due to the electrification of automotive systems. The goal of fault-tolerant systems is to handle occuring faults under operational condition and enable the driver to get to a safe stop. This paper presents results from an extended survey on fault-tolerant vehicle design. It aims to provide a holistic view on the fault-tolerant aspects of a vehicular system. An overview of fault-tolerant systems in general and their design premises is given as well as the specific aspects related to automotive applications. The paper highlights recent and prospective development of vehicle motion control with integrated chassis control and passive and active fault-tolerant control. Also, fault detection and diagnosis methods are briefly described. The shift on control level of vehicles will be accompanied by basic structural changes within the network architecture. Control architecture as well as communication protocols and topologies are adapted to comply with the electrified automotive systems. Finally, the role of regulations and international standardization to enable fault-tolerant vehicle design is taken into consideration.

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Survey on fault-tolerant vehicle design

The growing concerns about the environmental issues caused by vehicles and a strive for better fuel economy, urge the legislators to introduce conservative regulations on vehicle testing and homologation procedures. To have accurate evaluations, driving cycles that can 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 of the presented work is to study the contribution of chassis and vehicle dynamics settings on tyre rolling loss in comparison with the original assumptions made in the NEDC, FTP and HWFET driving cycles. A half-car model including a semi-physical explicit tyre model to simulate the rolling loss is proposed. For the chosen vehicle and tyre characteristics, depending on the specific chassis settings and considered driving cycle, considerable difference up to 7% was observed between the energy consumption of the proposed- and conventional approach. The current work aims to provide the legislators with a better insight into the real effects of chassis and vehicle dynamics during the certification process to further improve the test related procedures required for homologation such as generation of road load curves. I.e., the aim is not to provide a new homologation process, since there are also other effects such as road roughness and tyre temperature that need to be considered. The results are also of interest for the vehicle manufacturers for further considerations during test preparation as well as in the development phase in order to reduce the environmental impacts.

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Energy efficiency analyses of a vehicle in modal and transient driving cycles including longitudinal and vertical dynamics

For at least 50 years, the interest in understanding and reducing the rolling resistance of pneumatic tyres has been growing. This interest is driven by the need to reduce vehicle fuel consumption ...

Jenny Jerrelind

Papers

Nonlinear dynamics of parts in engineering systems

Control of near-grazing dynamics in impact oscillators

Survey on fault-tolerant vehicle design

Energy efficiency analyses of a vehicle in modal and transient driving cycles including longitudinal and vertical dynamics

Rolling resistance and its relation to operating conditions: A literature review: