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Technical Paper

Fault Detection Algorithm Design for Electro-Mechanical Brake

Electro-Mechanical Brake (EMB) systems can provide improved braking and stability functions such as ABS, EBD, TCS, ESC, BA, ACC, etc. For the implementation of the EMB systems, reliable and robust fault detection algorithm is required. In this study, a model-based fault detection algorithm is designed based on the analytical redundancy method in order to monitor possible faults in EMB systems. The performance of the proposed model-based fault detection algorithm is verified in simulations. The effectiveness of the proposed algorithm is demonstrated in various faulty cases.
Technical Paper

Effect of Air-Conditioning on Driving Range of Electric Vehicle for Various Driving Modes

Under the present effort to decrease of air pollution, Electric Vehicles (EVs) are appeared and developed. EVs are running by using electrical energy resource by supporting of battery packs. The effect of air-conditioning has proven to be a serious problem to the point of battery depleting. Thus in the present study, effects of air conditioning (i.e., cooling and heating) on driving range were studied for various driving modes including UDDS, HWFET, and NEDC. The result shows that EV energy efficiency is opposing the usual trend of internal combustion engine vehicle's fuel consumption in highway driving mode than urban driving mode. In highway mode, EV energy efficiency and driving range also decease than urban driving mode. This status was influenced on motor characteristic which torque decrease in high speed rotating conditions and highway driving mode consist of constant speed velocity so it couldn't use the regenerative braking system effectively.
Technical Paper

A Bistate Control of a Semiactive Automotive Suspension

The purpose of this paper is to develop and experimentally validate a practical and effective technique for the automatic regulation of a hydraulic semiactive vibration absorber (SAVA) for automobiles. The work relies on a consistent hydraulic model of the actuator dynamics that includes the effects of fluid compressibility and a nonlinear viscous loss characteristic. A bistate control algorithm is developed using a Lyapunov approach that seeks to dissipate the energy of the system. The performance of the proposed semiactive damper design on a quarter car model of an automobile suspension is established experimentally on a vibrating test stand. The work provides evidence that the inexpensive hardware design makes it possible to improve the ride and handling performance.
Technical Paper

Driving Posture Evaluation through Electroencephalographic Measurement and Digital Human Modeling

Drivers’ physical and physiological states change with prolonged driving. Driving for extended periods of time can lead to an increased risk of low back pain and other musculoskeletal disorders, caused by the discomfort of the seats. Static and dynamic are the two main categories must be considered within the seating development. The posture and orientation of the occupant are the important factors on static comfort. Driving posture measurement is essential for the evaluation of a driver workspace and improved seat comfort design. This study evaluated the comfortable driving posture through physiological and ergonomics measurements of an automotive premium driver seat. The physiological evaluation includes electroencephalographic (EEG) for brain waves, Biopac’s AcqKnowledge program, and subjective measurements on 32 healthy individuals. JACK simulation was used for the ergonomics evaluation, i.e., the magnitude of the spinal loads about lumbar vertebrae was estimated.
Technical Paper

Intention Aware Motion Planning with Model Predictive Control in Highway Merge Scenario

Human drivers navigate by continuously predicting the intent of road users and interacting with them. For safe autonomous driving, research about predicting future trajectory of vehicles and motion planning based on these predictions has drawn attention in recent years. Most of these studies, however, did not take into account driver’s intentions or any interdependence with other vehicles. In order to drive safely in real complex driving situations, it is essential to plan a path based on other driver’s intentions and simultaneously to estimate the intentions of other road user with different characteristics as human drivers do. We aim to tackle the above challenges on highway merge scenario where the intention of other road users should be understood. In this study, we propose an intention aware motion planning method using finite state machine and model predictive control without any vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communications.
Technical Paper

Development of an Injector Driver for Piezo Actuated Common Rail Injectors

In CRDI diesel engines, the piezo injector is gradually replacing the solenoid injector due to the quick response of the actuator. Operating performance of the injectors in the CRDI diesel engine has an influence on engine emissions. Therefore, accurate injector control is one of the most important parts of the CRDI engine control. The objective of this paper is the development of a piezo injector driver for CRDI diesel engines. Electrical characteristics of the piezo injector were analyzed. A control strategy for charging and discharging the actuator are proposed. The developed injector driver is verified by experiments under various fuel pressures, injection durations and driving circuit voltages.
Technical Paper

Sensor Fault Detection Algorithm for Continuous Damping Control(CDC) System

This paper presents a model based sensor fault detection and isolation algorithm for the vertical acceleration sensors of the Continuous Damping Control (CDC) system, installed on the sprung mass. Since sensor faults of CDC system have a critical influence on the ride performance as well as the vehicle stability, the sensor fault detection algorithm must be implemented into the overall CDC algorithm. In this paper, each vertical acceleration sensor installed on the sprung mass (two in the front corners and one in the rear) separately estimates the vertical acceleration of the center of gravity of the sprung mass. Then, the sensor fault is detected by cross-checking all three vertical acceleration estimates independently obtained by the each vertical acceleration sensor.
Technical Paper

Offset Compensation Algorithms for the Yaw Rate and Lateral Acceleration Sensors

The paper presents a new offset compensation method of a yaw rate sensor and a lateral acceleration sensor. It is necessary to compensate the offsets of the analog sensors, such as the yaw rate sensor and the lateral acceleration sensor, to acquire accurate signals. This paper proposes two different offset compensation algorithms, the sequential compensation method and the model based compensation method. Both algorithms are combined with the algorithm map depending on the vehicle driving status. The proposed algorithm is verified by the computer simulations.
Technical Paper

A Fault Detection Method for Electric Parking Brake (EPB) Systems with Sensorless Estimation Using Current Ripples

A fault detection method with parity equations is proposed in this paper. Due to low cost implementation, the velocity of a motor is not measurable in EPB systems. Therefore, residuals are not reliable with a low resolution encoder to estimate the motor velocity. In this paper, we propose a fault detection method with sensorless estimation using current ripples. The method estimates position and velocity of the motor by detecting periodical oscillations of the armature current caused by rotor slots. This method could estimate position and velocity of the motor with less computational effort than a state observer. Moreover, the method is less sensitive to motor parameters than model-based estimation methods. The effectiveness of this method is validated with experimental data. The simulation results show that various faults have their own residual patterns. Therefore, we could detect the fault by monitoring the residual signals.
Technical Paper

Software-in-the-Loop Simulation Environment Realization using Matlab/Simulink

This paper presents the Matlab/Simulink-based Software-in-the-Loop Simulation (SILS) tool which is the co-simulator for temporal and functional simulations of control systems. The temporal behavior of a control system is mainly dependent on the implemented software and hardware such as the real-time operating system, target CPU and communication protocol. In this research, the SILS components with temporal attributes are specified as tasks, task executions, real-time schedulers, and real-time networks. Methods for realizing these components in graphical block representations are investigated with Matlab/Simulink, which is the most commonly used tool for designing and simulating control algorithms in control engineering. These components are modeled in graphical blocks of Matlab/Simulink.
Technical Paper

Smart Automotive Switch™ (SAS) for Improved Automotive Electronic Control Systems

Electromechanical relays that are coupled with fuses have been used for controlling electrical loads in vehicles. In the past decade, semiconductor power switches have been developed for overcoming the physical limits of relays and fuses. Semiconductor power switches can not only replace relays and fuses but can also improve a system's reliability and efficiency. In this study, we introduce the Smart Automotive Switch (SAS), which is a smart high side power switch of Fairchild Korea semiconductor. Functional capabilities, such as power switching, protection and self-diagnosis of SASs are presented in case studies involving, for example, headlights, glow plugs, and fuel pump control systems. Through these experimental studies, the suitability of SASs is validated for designing improved automotive electronic control systems.
Technical Paper

Development of a Vehicle Electric Power Simulator for Optimizing the Electric Charging System

The electric power system of a modern vehicle has to supply enough electrical energy to numerous electrical and electronic systems. The electric power system of a vehicle consists of two major components: a generator and a battery. A detailed understanding of the characteristics of the electric power system, electrical load demands, and the driving environment such as road, season, and vehicle weight are required when the capacities of the generator and the battery are to be determined for a vehicle. In order to avoid the over/under design problem of the electric power system, an easy-to-use and inexpensive simulation program may be needed. In this study, a vehicle electric power simulator is developed. The simulator can be utilized to determine the optimized capacities of generators and batteries appropriately. To improve the flexibility and easy usage of the simulation program, the program is organized in modular structures, and is run on a PC.
Technical Paper

Atomization Characteristics of Common-rail Diesel Injector with Multi-hole

In this work, experimental and numerical study was performed to investigate the macroscopic spray structure and the spray characteristics of common rail type high-pressure injector with multi-hole. The global spray structure and microscopic characteristics of high-pressure diesel injector were investigated at various injection and ambient pressures. Spray developing process and spray tip penetration were obtained by spray visualization system, and the quantitative spray characteristics such as local Sauter mean diameter were measured by using phase Doppler particle analyzer. The numerical study was conducted to analyze the atomization characteristics of common-rail type injector at the same conditions with the experiment. In order to improve the prediction accuracy, the numerical analysis was modified using the hybrid breakup model that is composed of primary breakup and secondary breakup.
Technical Paper

A Sampling Period Decision for Robust Control of Distributed Control System using In-Vehicle Network

This paper presents a preliminary study of a sampling period decision for robust control of a distributed control system based on an in-vehicle network with three types of data (real-time synchronous data, real-time asynchronous data, and nonreal-time asynchronous data). The architecture of automotive systems is currently changing from a number of standalone electronic control units (ECUs) to a functionally integrated distributed system which is linked by a network. The control performance of the integrated networked control system can be changed by the characteristics of time delays among the application ECUs. A basic parameter for a scheduling method of the networked control systems, a maximum allowable delay bound is used, which guarantees stability of the networked control system, and it is derived from the characteristics of the given plant using presented theorems.
Technical Paper

The Design of a Controller for the Steer-by-Wire System Using the Hardware-In-the-Loop-Simulation System

In this study, a Steer-by-Wire (SBW) controller was developed using the Hardware-In-the-Loop-Simulation (HILS) system. The mechanism of the HILS system consists of a hydraulic actuator for a lateral force on the front tires in a real vehicle. There are two motors in the SBW system controlled by one Electronic Control Unit (ECU). One motor in the steering wheel is to improve the driver's steering feel and the other motor in the steering linkage is to improve the vehicle maneuverability. The SBW controller's availability was verified through a number of simulations on the HILS system. The SBW fail-safe logic was tested through various simulations of the hazard environment on the HILS system. Consequently, the control logic of the SBW system was developed easily and safely in a laboratory.
Technical Paper

Feedback Error Learning Neural Networks for Air-to-Fuel Ratio Control in SI Engines

A controller is introduced for air-to-fuel ratio management, and the control scheme is based on the feedback error learning method. The controller consists of neural networks with linear feedback controller. The neural networks are radial basis function network (RBFN) that are trained by using the feedback error learning method, and the air-to-fuel ratio is measured from the wide-band oxygen sensor. Because the RBFNs are trained by online manner, the controller has adaptation capability, accordingly do not require the calibration effort. The performance of the controller is examined through experiments in transient operation with the engine-dynamometer.
Technical Paper

Implementation-Conscious Rapid Control Prototyping Platform for Advanced Model-Based Engine Control

In the extremely cost-sensitive and competitive automotive industry, manufacturers and suppliers are constantly searching for means to reduce both time-to-market and development costs. As a kind of solution to satisfy these requirements, Rapid-control prototyping (RCP) has established itself as viable technology, albeit not everywhere yet. One big gap in the development process, however, is the transfer form RCP to a target implementation with all its limitations. This paper presents a new RCP platform, which aims to provide a consistent environment both at the RCP step and at the target code implementation step. To achieve this goal, the proposed prototyping system is designed very similar to the real production ECU as much as possible, and it supports all the features, which are needed in the RCP.
Technical Paper

Automotive ADAS Camera System Configuration Using Multi-Core Microcontroller

It has become an important trend to implement safety-related requirements in the road vehicles. Recent studies have shown that accidents, which occurred when drivers are not focused due to fatigue or distractions, can be predicted in advance when using safety features. Advanced Driver Assistance Systems (ADAS) are used to prevent this kind of situation. Currently, many major tiers are using a DSP chip for ADAS applications. This paper suggests the migration from a DSP configuration to a Microcontroller configuration for ADAS application, for example, using a 32bit Multi-core Microcontroller. In this paper, the following topics will be discussed. Firstly, this paper proposes and describes the system block diagram for ADAS configuration followed by the requirements of the ADAS system. Secondly, the paper discusses the current solutions using a DSP. Thirdly, the paper presents a system that is migrated to a Multi-core microcontroller.
Journal Article

Validation of a Seamless Development Process for Real-time ECUs using OSEK-OS Based SILS/RCP

An efficient development environments such as Software-in-the-Loop Simulation (SILS) and Rapid Control Prototyping (RCP) have been widely used to reduce the development time and cost of real-time ECUs. However, conventional SILS does not consider temporal behaviors caused by computation time, task scheduling, network-induced delays, and so on. As a result, the control performance of ECU is likely to be degraded after implementation. To overcome this problem, SILS/RCP which considers the temporal behaviors was suggested in the previous research. In this study, we validated the proposed SILS/RCP environments which are used to design an Electronic Stability Control (ESC) system which is one of the hard real-time control systems. The proposed SILS/RCP environments make it possible to realize ECUs in the early design phase by considering temporal behaviors.
Journal Article

Formal Design Process for FlexRay-Based Control Systems with Network Parameter Optimization

FlexRay is a deterministic and fault-tolerant in-vehicle network(IVN) protocol. It is expected to become a practical standard for automotive communication systems. According to the FlexRay protocol specifications, there are about 60 configurable parameters which should be determined in the design phases. The parameters increase the complexities of FlexRay-based control system development. In this study, we are suggesting a formal design process for FlexRay-based control systems, which is focused on network parameter optimization. We introduce design phases from functional system models to implementations. These phases present formal ways for task allocation, node assignment, network configuration, and implementations. In the network configuration phase, two FlexRay core parameters are selected to optimize network design. Optimal methods of the core parameters provide concise guide lines for optimal communication cycle length and optimal static slot length.