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The automotive industry’s journey towards fully autonomous vehicles brings more and more vehicle control systems. Additionally, the reliability and robustness of all these systems must be guaranteed for all road and weather conditions before release into the market. However, the ever-increasing number of such control systems, in combination with the number of road and weather conditions, makes it unfeasible to test all scenarios in real life. Thus, the performance and robustness of these systems needs to be proven virtually, via vehicle simulations. The key challenge for performing such a range of simulations is that the tire performance is significantly affected by the road/weather conditions. An end user must therefore have access to the corresponding tire models. The current solution is to test tires under all road surfaces and operating conditions and then derive a set of model parameters from measurements.

This paper proposes a simplified method to make the flux table considering the magnetic flux variation of the IPMSM (Interior Permanent Magnet Synchronous Machine) caused by temperature change in vehicle traction applications. Nowadays, normally an IPMSM with a rare-earth magnet is used for HEV traction applications. But because the flux density of the magnet varies with temperature, the optimal operating points, such as MTPA (Maximum Torque Per Ampere) and MTPV (Maximum Torque Per Voltage) of the motor drift according to temperature change. Those operating points can be expressed in a lookup table, that is, a flux table obtained by off-line experiment, which produces the DQ-axis current command with respect to the torque and flux reference. To reflect this temperature dependence in control, usually flux tables are generated at high, medium and low temperatures. Conventionally, all the three tables are constructed by experiment, which takes a great deal of time.

When two identical brakes are simultaneously tested on a vehicle chassis dynamometer, very often the left hand brake is found to squeal more or less than the right hand brake, all at different frequencies. This study was performed to develop some understanding of this puzzling phenomenon. It is found that as the wear rate difference between the inner pad and the outer pad increases, low frequency (caliper and knuckle) squeals occur more and more, and as the differential wear becomes larger and larger, high frequency (disc) squeals occur less and less, finally disappearing all together. Discs and calipers are found to affect the differential pad wear, in turn affecting brake squeal generation.

The effects of pad properties and thermal coning of discs on high speed judder were investigated using dynamometer and vehicle tests. The friction materials of different thermal conductivities were manufactured and the discs were design-modified to control the thermal coning during braking under high speed conditions. Brake Torque Variation(BTV) was measured to evaluate the judder propensity in the dynamometer tests and the vibration on steering wheel and brake pedal was measured in the vehicle tests. The results showed that the increase of thermal conductivity of pad could not affect the judder propensity during high speed braking below 350°C of disc temperature, however better disc design reduced judder propensity due to the lower thermal deformation. Moreover, the increase of pad compressibility can reduce judder propensity due to the increase of damping capacity.

EMB (Electro-Mechanical Brake) which converts electrical motor power to brake clamping force at each wheel is a system that has been investigated and developed by various automotive part suppliers through the years. In particular, as the number of electrically powered vehicles, such as hybrid electric vehicles, electric vehicles and fuel cell electric vehicles, has expanded, the EMB has received increased interest due to its fast response that is much suited for effective cooperative control with regenerative braking. However, issues such as cost competitiveness, reliability and regulations need to be solved for commercialization [1-2]. A new concept, the hybrid Electro-Mechanical Brake (hEMB) is characterized by a dual piston structure linked by hydraulics inside of the caliper. It is possible to reduce the required motor power and increase the level of emergency back-up braking through the amplification effect of the dual piston mechanism [3].

The development trend of new vehicles is to shorten the development period, diversify the models, and produce small amounts compared to the past. The current development process of braking systems is difficult to meet recent development trends, and it is more difficult to shorten the development period in the verification process that requires actual products. In this paper, we developed a 1-D Simulation of AMESim, MATLAB/Simulink Co-Simulation model of Hyundai Mobis iMEB(Integrated Mobis Electronic Brake) system for eco-friendly vehicles. If hydraulic braking is applied more than the tire grip force during braking, tire slip occurs, and if the rear wheel is locked before the front wheel, stability is lost, so it is advantageous to decide design parameter of brake system to make the front wheel first locked in consideration of design parameters of each vehicle.

Ar plasma treatment was carried out to reduce the sheet resistance of indium tin oxide (ITO) thin films. To verify how the concentration of oxygen vacancies in the film increased with the Ar plasma treatment time, cumulative and continuous plasma treatments were conducted. In addition, to improve the transmittance and reduced the sheet resistance the PDMS layer was as a stamp on the surface of ITO. The oxidation of the PDMS stamp appears to be a key factor to improve the characteristics of ITO thin film. Furthermore, an indium-tin-oxide (ITO) thin film with approximately 50 nm thickness was successfully synthesized on glass substrates by using a fully aqueous sol-gel process. The annealing temperature and argon plasma treatment time appear to be key factors in reducing resistivity and increasing the transmittance of the thin film.

A series of experiments and computational analysis were carried out on the flow around a bluff body. Some non-streamlined ground vehicles, buildings and pipelines near to the ground could encounter very dangerous situations because of the unsteady wind loading caused by the periodic vortex shedding behind the bluff body. A two-dimensional bluff body model was used to simulate flow in the wake region. Spectral analysis of the velocity profiles in the underbody region was also used to examine the influence of the underbody flow in the wake region. By using a flow visualization technique, the critical gap height and the separation line on the ground were investigated for various gap heights and boundary layer thicknesses. Additionally, the 2-D Incompressible Navier-Stokes equation with an ε - SST (Strain Shear Stress Transport) turbulence model was used for comparison with experimental results.

The history of the brake system for the passenger vehicles is no shorter than that of the automobile itself. With the long history, its performance, efficiency and reliability have been dramatically improved and as a result, even leading brake system suppliers now find it very difficult to come up with breakthrough ideas for further optimization of the current brake systems. In addition, as the powertrain of the vehicles has also been improved, the requirements of the brake system have become much more severe than before, leading to a trend of increasing the system size and weight especially for the parts belong to unsprung mass. In the case of high-end vehicles, the system was further optimized using expensive materials such as ceramic, carbon-fiber, etc. However, most normal vehicles have been developed without any significant changes in the existing systems. This decade-long trend of developing braking parts has seen a big change “electrification of the vehicle”.

The integrated control system of Electronic Stability Control (ESC) and Motor-Driven Power Steering (MDPS) improves vehicle performance and extends functions via CAN network without any hardware modification. Although the ESC and MDPS integrated system does not improve vehicle behavior directly, it can inspire drivers to steer to the right direction by changing steering torque assistance characteristics. There are two different ways to control both ESC and MDPS systems: Top-down and Parallel control mode. First, the Top-down control mode, which is already widely used on the market, imposes ESC on the additional functions of ESC+MDPS integrated system. On the contrary, the Parallel control mode distributes the functions to ESC and MDPS, therefore each system does their own role and cooperates on special events. In this study, the parallel control mode controller is proposed and compared with the Top-down control mode.

This paper describes an investigation into multi-core processing architecture for implementation of a Unified Chassis Control (UCC) algorithm. The multi-core architecture is suggested to reduce the operating load and maximization of the reliability to improve of the UCC system performance. For the purpose of this study, the proposed multi-core architecture supports distributed control with analytical and physical redundancy capabilities. In this paper, the UCC algorithm embedded in electronic control unit (ECU) is comprised of three parts; a supervisor, a main controller, and fault detection/ isolation/ tolerance control (FDI/FTC). An ECU is configured by three processors, and a control area network (CAN) is also implemented for hardware-in-the-loop (HILS) evaluation. Two types of multi-core architectures such as distributed processing, and triple voting are implemented to investigate the performance and reliability.

Recently, there’s a massive flow of change in the automotive industry with the coming era of electric vehicles and self-driving (autonomous) vehicles. The automotive braking system field is not an exception for the change and there are not only lots of new systems being developed but also demands for researches for optimizations of conventional brake systems fitting to the newly appeared systems such as E-Booster and Electric Motor Brake (EMB) Caliper. Taking the Electric Motor Brake Caliper for example, it is considered as a very important and useful system for autonomous vehicles because the motor actuator of the caliper is much easier to control with ECUs compared to the conventional hydraulic pressure system. However, easy of control is not the only thing that excites brake system engineers.

ABS assembly is supported by the mounting bracket which is installed at the body inside engine room. Such feature of the mounting bracket requires consideration of durability performance under the dynamic random loads imposed by engine excitation. So, modal parameters, such as natural frequencies and mode shapes, of ABS assembly and its bracket should be considered when evaluating the fatigue life. Therefore, fatigue analyses and experiments of ABS assembly and its bracket were performed in the frequency domain rather than the time domain. After that, analysis results were compared and correlated with experimental results, and the analysis method was updated to improve analysis accuracy.

The current braking system of a vehicle includes a parking braking system, which consists of a Motor on Caliper (MOC) that generates hydraulic main braking and electric parking braking through a caliper structure. When designing the MOC braking system, it is important to consider an analytical model that can predict the performance of the parking clamping force and the torque generated between the disk and caliper interactions. However, in previous designs, system predictions were often based on simplified structural calculations or incomplete Finite Element Method (FEM) analysis. In this paper, a study was conducted to predict the system performance using Multi-flexible Body Dynamics (MFBD) analysis. Firstly, a kinematic model (MBD) was developed for the Electric Parking Brake (EPB) system currently used in mass-produced vehicles. And the MBD model which based on kinematics was the initial model for this study.

Many automotive companies have recently introduced Virtual Product Development (VPD) techniques. The VPD helps engineers to reduce the number of design changes, speed up development time and improve product quality by utilizing CAE early in the design cycle before prototypes are ever created. In the VPD environment, however, simulation engineers inevitably perform a large number of analyses due to a number of design changes and validations of performance and reliability. In effect, the engineers have to follow many steps of analysis processes when using various kinds of simulation applications, which may require repetitious manual works such that it is easy to make mistakes. In an effort to solve these problems, automation software incorporating various types of analysis processes for automotive suspension components, DAAS (Durability Analysis Automation System) has been developed.

In-vehicle driving tests for evaluating performance of vehicle control devices are often time-consuming, expensive, and not reproducible. Using hardware-in-the-loop simulation scheme, actual control devices can be easily tested in real time in a closed loop with a virtual vehicle. This advantage has made HILS systems popular as testbench lately in automotive industries. This paper describes a PC-based HILS system for ABS that has been developed in Matlab environment with real-time rapid prototyping tools. Also presented in this paper is a semi-empirical vehicle dynamic model that has been designed to account for kinematic and compliant characteristics of the suspension system from rig tests.

Future technology trends of commercial vehicle steering components can be divided into three types. Environment-friendly technologies for environment-related regulations such as reducing emissions and improving fuel efficiency, and technology for driving convenience using electric steering control systems, and safety technology to protect drivers, passengers, nearby vehicles and pedestrians. Heavy duty commercial vehicles require a high-power steering system that used engine-driven hydraulic pump systems (generally used min 120bar, 17Liter/min) compared to passenger cars. In recent technical trend, In order to improve fuel efficiency and realize autonomous driving technology, we designed EHPS and Motor driven electric control actuator with the same structure as C-EPS.

There have been many kinds of simplifications and limitations in evaluating the thermal performance of disc brake when using the analytic technologies which were established before. But now new technology of virtual test with several advanced analytic techniques was developed to evaluate the thermal performance without any possibility of great errors that used to happen for the earlier time-consuming analyses. As a result, it was estimated that the new virtual test technology could afford to replace the physical dynamo test since the reliability of virtual test technology was reasonably verified with the existing data measured in dynamo test.

It is widely believed or speculated that higher pad compressibility leads to reduced brake squeal and that caliper design can affect brake squeal. After encountering anecdotal contradictory cases, this investigation was undertaken to systematically generate basic data and clarify the beliefs or speculations. In order to adjust pad compressibility, it is common to modify pad molding temperatures, pressures and times, which in addition to changing the compressibility, changes friction coefficient and physical properties of the pad at the same time. In order to separate these two effects, NAO disc pads were prepared under the same molding conditions while using different thicknesses of the underlayer to achieve different compressibilities, thus changing the compressibility only without changing the friction coefficient and physical properties of the pad.

This paper describes a lateral disturbance estimator for an application to a Motor Driven Power Steering (MDPS)-based driving assistant system. A vehicle motion can be disturbed laterally by wind force or load from bank angle acting on the vehicle in the lateral direction. An MDPS-based driving assistant system can be used to reduce steering effort of a human driver in a driving situation with lateral disturbance. In designing the MDPS-based driving assistant system, the lateral wind disturbance should be estimated to determine an assistant torque. An estimator for the vehicle lateral disturbance estimation has been developed. The proposed estimator consists of two parts: a tire self-aligning torque estimator and the lateral disturbance estimator. The lateral disturbance estimator has been designed on the basis of a 2-DOF bicycle model with available sensor signals from the MDPS module. A numerical simulation has been conducted in order to evaluate the proposed estimator.