The prospect of driverless cars wide-scale deployment is imminent owing to the advances in robotics, computational power, communications, and sensor technologies. This promises highway fatality reductions and improvements in traffic and fuel efficiency. Our understanding of the effects arising from commuting in autonomous cars is still limited. The novel concept of the loss of driver controllability is introduced here. It requires a reassessment of vehicle's comfort criteria. In this review paper, traditional comfort measures are examined and autonomous passenger awareness factors are proposed. We categorize path-planning methods in light of the offered factors. The objective of the review presented in this article is to highlight the gap in path planning from a passenger comfort perspective and propose some research solutions. It is expected that this investigation will generate more research interest and bring innovative solutions into this field.

In the Passenger Seat: Investigating Ride Comfort Measures in Autonomous Cars

Linear Systems, Random Data, Spectra Zero-Memory Nonlinear Systems Bilinear and Trilinear Systems Nonlinear System Input/Output Relationships Square-Law and Cubic Nonlinear Systems Statistical Errors in Nonlinear Estimates Parallel Linear and Nonlinear Systems.

Nonlinear System Analysis and Identification from Random Data

The need for more efficient and renewable means of transport makes the development of hybrid electric vehicles (HEVs) an important topic for both automobile manufacturers and academic researchers. Noise, vibration, and harshness (NVH) of a vehicle are important factors for vehicle users and essential for successful commercialization of this vehicle type. This paper is a compact state-of-the-art review of both NVH characteristics and relevant suppression methods for HEVs. The NVH-related problems are categorized into three categories: engine, powertrain, motor-related. A detailed overview of each category/problem-type is provided, the NVH-suppression methods for different types of HEVs are introduced, and their respective advantages discussed. In addition, emerging developments and ideas for future improvements are summarized. As a result, the paper should be particularly helpful for researchers, who are interested in the development of high-performance HEVs that can provide both substantially improved ride-comfort and reduced energy-consumption.

Noise and vibration suppression in hybrid electric vehicles: State of the art and challenges

Vehicle noise, vibration and harshness (NVH) is an important vehicle attribute. It is usually among the top five attributes in terms of its priority in the design of any vehicle type. Like other attributes of safety, performance, dynamics and fuel economy, this attribute has to be considered closely in the design process. This manuscript presents an overview of automotive NVH engineering. It classifies the interior noise into powertrain-related NVH, road- and tyre-related NVH and wind-related NVH. This paper also discusses brake- and chassis-related NVH, squeak and rattle and electromechanical-related NVH. In addition, the paper addresses exterior NVH, frequently described as drive-by NVH. The phenomenon is divided into usual or expected NVH and unusual or unexpected NVH. The paper provides a review of some of the recent literature in the field of automotive NVH.

Overview of automotive noise and vibration

Vehicle noise, vibration and harshness (NVH) is usually among the top five attributes in terms of its priority in the design of automotive vehicles. Its priority in other types of vehicles (e.g., aerospace) is also important. Like other attributes of safety, performance, dynamics, fuel economy, NVH has to be considered closely in the design process. This manuscript presents a summary of recent research in the general area of NVH with an emphasis in the automotive field. It follows up on a previous review and classifies the phenomena by the main sources of NVH into powertrain, road and tyre, wind and other NVH. The last includes brake and chassis, squeak and rattle, electromechanical NVH, exterior (or drive-by) NVH and others. The paper provides a review of some of the recent literature in this field.

Recent Research on Vehicle Noise and Vibration

Experimental characterization and analysis of wet belt friction and the vibro-acoustic behavior

This paper presents a model to characterise V-ribbed belt (Micro-VTM) noise in accessory belt drive system (ABDS), or front-end accessory drive (FEAD) of automotive engines. It has been known that radial friction-induced vibrations generate belt misalignment noise and tangential friction-induced vibrations relates to belt slip noise. In this study, these two kinds of vibrations are found essentially different, and they are formulated mathematically by using forced vibration equation and self-excited vibration equation respectively. The formulations are consistent with conventional experimental results. A series of new tests were run to assess the properties of the belt noise using industry standard test rigs. The test results are agreeable with the results derived directly from the formulations. The proposed model is expected to provide accessory drive designers with insight into the issues associated with improving the overall noise performance of ABDS system.

A model and experimental investigation of belt noise in automotive accessory belt drive system

This paper presents an investigation of V-ribbed belt (Micro-V TM ) wet friction and friction-induced slip noise in Accessory Belt Drive Systems (ABDS). A set of experiments was conducted by using an industry standard test rig and a standard material friction tester. A theoretical analysis and model are presented to elaborate the results. The tribological property of the interface is characterised to be unsteady mixed lubrication with water, which possesses the feature of negative slope of friction with velocity. The friction-induced dynamic instability and noises are also investigated. It is shown that the noise is directly associated with the negative slope of the friction-velocity curve.

Wet belt friction-induced dynamic instability and noise in Automotive Accessory Belt Drive Systems

This paper presents the nonlinear characteristics of typical automotive seat cushion structure. As discussed in an earlier paper by the authors (Pang et al., 2004), the experimental transfer functions between the seat butt and the seat track vary with changes in the excitation levels. Both the magnitudes and frequencies of the transfer functions shift to smaller values as the excitation increases. Two nonlinear models are established to reveal this nonlinear phenomenon in the automotive seats. One of the models is combined with the ISO linear human body model to form a nonlinear seat-human body model. The simulated transfer functions between the head and the seat track, between the body and the seat track, and between the seat butt and the seat track are correlated with experimental results. The models proposed here are intended to help engineers optimise the ride quality of the vehicle.

Gang Sheng

Papers

Overview of automotive noise and vibration

Experimental characterization and analysis of wet belt friction and the vibro-acoustic behavior

A model and experimental investigation of belt noise in automotive accessory belt drive system

Wet belt friction-induced dynamic instability and noise in Automotive Accessory Belt Drive Systems

Nonlinear seat cushion and human body model