Search Results

This paper presents the design and evaluation of an emergency driving support (EDS) algorithm. The control objective is to assist driver's collision avoidance maneuver to overcome a hazardous situation. To support driver, electrically controllable chassis components such as motor driven power steering (MDPS) and differential braking and surrounding sensor systems such as radar and camera are used. The EDS algorithm is designed for 3 parts: monitoring, decision, and control. The proposed EDS algorithm recognizes a collision danger using minimum lateral acceleration to avoid collision and time-to-collision (TTC) and driver's intention using sensor systems. The control mode is determined using the indices from monitoring process and the collision avoidance trajectory is derived with trapezoidal acceleration profile (TAP).

This paper describes a driving control algorithm based on a skid steering for a Robotic Vehicle with Articulated Suspension (RVAS). The RVAS is a kind of unmanned ground vehicle based on a skid steering using independent in-wheel drive at each wheel. The driving control algorithm consists of four parts: a speed controller for following a desired speed, a lateral motion controller that computes a yaw moment input to track a desired yaw rate or a desired trajectory according to the control mode, a longitudinal tire force distribution algorithm that determines an optimal desired longitudinal tire force and a wheel torque controller that determines a wheel torque command at each wheel in order to keep the slip ratio at each wheel below a limit value as well as to track the desired tire force. The longitudinal and vertical tire force estimators are required for the optimal tire force distribution and wheel slip control.

This paper describes the safety test simulation of electrical shock of FCV (Fuel Cell Vehicles) on human. Since FCV operates with high voltage, it is very dangerous to touch on or near the conductive parts. It may hurt human even when conductive parts are surrounded by protectors such as barriers or enclosures. Also various modes of a vehicle, such as driving, idle and failure, can affect electrical shock. It is difficult to carry out field experiments about electrical shock for FCV because of many combinations which depend on the operating voltages and the modes of a vehicle. And electrical safety of FCV must be verified before the manufacturing process. These are the main purposes of this study. MATLAB Simulink is the tool to conduct the simulation. All of the electronic devices in an FCV and a human body were modeled to measure current through human body when human touches on FCV. We performed the simulation with respect to driving, idle and failure mode.

In this paper, we investigate a method to calculate the dynamic instability of a disc brake system and propose a criterion of design modification. To estimate dynamic instability, complex eigenvalue analysis is performed for a brake system and the contribution factor of each component to an unstable complex mode is calculated using complex MAC(Modal Assurance Criteria). From the contribution factors, the most influential component is determined so as to decouple the complex mode, and its geometry is modified in view of the strain energy distribution. Evaluation through noise dynamometer tests verifies the reduction of squeal noises, and this is in accordance with the results of complex eigenvalue analysis.

This paper presents a real-time vehicle powertrain simulator and a pseudo real-time multi-vehicle platoon simulator. The developed powertrain simulator simulates the complex vehicle powertrain dynamics, including detailed shifting transients, in the PC environment in real time. The driver input is provided using a throttle pedal interfaced using the game port. The processor requirements vary depending on the simulation options selected. In the basic version, this requirement is only approximately 20% of a 300 MHz Pentium II- based PC. For multi-vehicle platoon simulation, a network configuration is proposed. It links several individual powertrain simulations via the TCP/IP network. This network platoon simulation is also linked to a server which graphically displays the multi-vehicle platoon operation. In this network configuration, due to a random delay in data transfer the simulation time kernel is made to lag real time.

Compliance elements such as bushings of a suspension system play a crucial role in determining the ride and handling characteristics of the vehicle. In this research, a general procedure for the optimum design of compliance elements to meet various design targets is proposed. Based on the assumption that the displacements of elastokinematic behavior of a suspension system under external forces are very small, linearized elastokinematic equations in terms of infinitesimal displacements and joint reaction forces are derived. Directly differentiating the linear elastokinematic equations with respect to design variables associated with bushing stiffness, sensitivity equations are obtained. The design process for determining the bushing stiffness using sensitivity analysis and optimization technique is demonstrated.

In order to reduce PM (Particulate Matter) emitted from diesel vehicles, we have been developing the particulate trap system using a burner since 1993. This AEFR system (Active Exhaust Feeding Regeneration System) shows considerably low peak temperatures and temperature gradients in the filter during the regeneration process. The AEFR system used the engine exhaust gas partially for the regeneration of the ceramic wall flow filter. It controlled the bypass flow rate of the engine exhaust gas actively for the combustion rate control of filtrated PM. The temperature distributions and temperature gradients in the filter during the regeneration process varied widely according to the regeneration control schemes. Scheme III has shown the most desirable peak temperatures and temperature gradients in the filter during the regeneration processes with AEFR system.