Refine Your Search

Search Results

Viewing 1 to 12 of 12
Technical Paper

Vibration Control of an Active Seat Suspension System Integrated Pregnant Woman Body Model

Proportional-integral-derivative (PID) controller is effective, popular and cost effective for a lot of scientific and engineering applications. In this paper, PID and fuzzy-self-tuning PID (FSTPID) controllers are applied to improve the performance of an active seat suspension system to enhance the pregnant woman comfort. The equations of motion of thirteen-degrees-of-freedom (13-DOF) active seat suspension system incorporating pregnant woman body model are derived and simulated. PID gains are tuned and estimated using genetic algorithm (GA) to formulate GA PID controller. In FSTPID, fuzzy logic technique is used to tune PID controller gains by selecting appropriate fuzzy rules using Matlab/Simulink software. Both controlled active seat suspension systems are compared with a passive seat suspension. Suspension performance is evaluated under bump and random road excitations in order to verify the success of the proposed controllers.
Technical Paper

Application of a Preview Control with an MR Damper Model Using Genetic Algorithm in Semi-Active Automobile Suspension

A non-linear mathematical model of a semi-active (2DOF) vehicle suspension using a magnetorheological (MR) damper with information concerning the road profile ahead of the vehicle is proposed in this paper. The semi-active vibration control system using an MR damper consists of two nested controllers: a system controller and a damper controller. The fuzzy logic technique is used to design the system controller based on both the dynamic responses of the suspension and the Padé approximation algorithm method of a preview control to evaluate the desired damping force. In addition, look-ahead preview of the excitations resulting from road irregularities is used to quickly mitigate the effect of the control system time delay on the damper response.
Technical Paper

Vibration Control of Active Vehicle Suspension System Using Optimized Fuzzy-PID

In this paper, a fuzzy-PID controller is applied in a half vehicle active suspension system to enhance vibration levels of vehicle chassis and passenger seat. The fuzzy-PID controller consists of fuzzy and PID connecting in a series manner, the fuzzy output is considered as the PID input. Genetic Algorithm (GA) is selected to tune controller parameters to obtain optimal values that minimize the objective function. The equations of motion of five-degrees-of-freedom active half-vehicle suspension system are derived and simulated using Matlab/Simulink software. Double bumps and random road excitations are used to study the performance of suspension systems including bounce and pitch motion. The performance of the active suspension system using optimized fuzzy-PID controller is compared with conventional passive to show the efficiency of the proposed active suspension system.
Journal Article

Analysis of Vehicle Lateral Dynamics due to Variable Wind Gusts

This study presents a practical theoretical method to judge the aerodynamic response of buses in the early design stage based on both aerodynamic and design parameters. A constant longitudinal velocity 2-DOF vehicle lateral dynamics model is used to investigate the lateral response of a bus under nine different wind gusts excitations. An appropriate 3-D CFD simulation model of the bus shape results is integrated with carefully chosen design parameters data of a real bus chassis and body to obtain vehicle lateral dynamic response to the prescribed excitations. Vehicle model validity is carried out then, the 2-DOF vehicle lateral dynamics model has been executed in MATLAB Simulink environment with the selected data. Simulation represents the vehicle in a straight ahead path then entered a gusting wind section of the track with a fixed steering wheel. Vehicle response includes lateral deviation (LD), lateral acceleration (LA), yaw angle (YA) and yaw rate (YR).
Technical Paper

On The Integration of Actively Controlled Longitudinal/Lateral Dynamics Chassis Systems

Integral Control strategy for vehicle chassis systems had been of great interest for vehicle designers in the last decade. This paper represents the interaction of longitudinal control and lateral control. In other words the traction control system and handling control system. Definitely, tire properties are playing a vital role in such interaction as it is responsible for the generated forces in both directions. A seven degrees of freedom half vehicle model is derived and used to investigate this interaction. The vehicle body is represented as a rigid body with three degrees of freedom, lateral and longitudinal, and yaw motions. The other four degrees are the two rotation motion of the front wheel and the rear wheel. This two motions for each wheel are spin motion and the steering motion. The traction controller is designed to modulate engine torque through adjusting the throttle angle of the engine upon utilized adhesion condition at the driving road wheels.
Technical Paper

Modeling of Vehicle Drum Brake for Contact Analysis Using Ansys

A non-contact analysis of a drum brake based on three-dimensional Finite Element analysis using Ansys is presented. The effect of drum-lining interface stiffness and line pressure on the interface contact is examined. The modal analysis of the vehicle drum brake is also studied to get the natural frequency and instability of the drum. It is shown that the unsymmetric modal analysis is efficient enough to solve this linear problem after transforming the non-linear behaviour of the contact between the drum and the lining to a linear behavior. A linear element which is used in the modal analysis is transferred to non-linear elements which are Targe170 and Conta173 that represent the drum and lining to study the contact analysis. The contact analysis problems are highly non-linear and require significant computer resources to solve it, however, the contact problem give two significant difficulties.
Technical Paper

Performance of Active Suspension with Fuzzy Control

Vehicle suspension along with tires and steering linkages is designed for safe vehicle control and to be free of irritating vibrations. Therefore the suspension system designs are a compromise between ride softness and handing ability. However, this work is concerned with a theoretical investigation into the ride behavior of actively suspended vehicles. It is based on using fuzzy logic control (FLC) to implement a new sort of active suspension system. Comparisons between the behavior of active suspension system with FLC with those obtained from active systems with linear control theory (LQR), ideal skyhook system and the conventional passive suspension systems. Results are introduced in such a way to predict the benefits that could be achieved from fuzzy logic system over other competing systems. Furthermore, a controller is designed and made by using results of FLC system, theoretical inputs are used to examine the validity of this controller.
Technical Paper

Interaction of Vehicle Ride Vibration Control with Lateral Stability Using Active Rear Wheel Steering

In this work the effects of vehicle vertical vibrations on the tires/road cornering forces, and then consequently on vehicle lateral dynamics are studied. This is achieved through a ride model and a handling model linked together by a non-linear tire model. The ride model is a half vehicle with four degrees of freedom (bounce and pitch motions for vehicle body and two bounce motions for the two axles). The front and rear suspension are a hydro-pneumatic slow-active systems with 6 Hz cut-off frequency designed based on linear optimal control theory. Vehicle lateral dynamics is modeled as two degrees (yaw and lateral motions) incorporating a driver model. An optimal rear wheel steering control in addition to the front steering is considered in the vehicle model to represent a Four Wheel Steering (4WS) system. The tire non-linearity is represented by the Magic Formula tire model.
Technical Paper

Hybrid Shape Optimization and Failure Analysis of Laminated Fibrous Composite E-Springs for Vehicle Suspension

A hybrid search optimization is presented in order to optimize hybrid laminated fibrous composite E-springs for vehicle suspension systems. This optimization is conducted with both of the geometrical configuration and laminate structure of the E-spring. A genetic algorithm along with a hill-climbing random-walk approach are used through a developed NURBS-based technique in order to conduct this optimization. A mathematical-modeling-based mid-ware technology is introduced in order to fully automate the optimization process through linking the run engines of mathematical modeling and finite element analysis from within the mathematical modeling engine. A hybrid approach of the inter-laminar shear stress and Tsai-Wu criteria is first implemented in order to identify failure indices of the resulting optimum shape and laminate structure.
Technical Paper

Experimental Investigation and Hybrid Failure Analysis of Micro-Composite E-Springs for Vehicle Suspension Systems

E-spring is a recent innovation in vehicle suspension springs. Its behavior and characteristics are investigated experimentally and verified numerically. The mechanical and frequency-response-based properties of E-springs are investigated experimentally at both of the structural and constitutional levels. Thermoplastic-based and thermoset-based fibrous composite structures of the E-springs are modified at micro-scale with various additives and consequently they are compared. The experimental results reveal that additives of micrometer-sized particles of mineral clay to an ISO-phthalic polyester resin of the composite E-spring can demonstrate distinguished characteristics. A hybrid approach of the inter-laminar shear stress and Tsai-Wu criteria is implemented in order to identify failure indices numerically at the utmost level of loading and verify the experimental results.
Technical Paper

On the Analysis of Drum Brake Squeal Using Finite Element Methods Technique

Many basic studies were conducted to discover the main reason for squeal occurrence in both disc and drum brake systems. As, it is well-known that the squealed brake system is more effective than the non-squealed brake system and it is also a common discomfort. So, cancellation of the squeal is not preferable, however, elimination of the brake squeal is a favorable. An approach to study the drum brake squeal is presented based mainly on the Finite Element Method (FEM) representation. The brake system model is based also on the model information extracted from finite element models for individual brake components. This finite element method (FEM) was used to predict the mode shape and natural frequency of the brake system after appropriate verification of FEM.
Technical Paper

Theoretical and Numerical Analysis of Fibrous Composite C-Springs

During the last few decades, fibrous composite materials have been diversified and replaced some traditional metallic materials. These materials provide high strength to weight ratio together with high environmental corrosion resistance. One of the basic engineering applications, which have been attracted by the properties of these composites, is the automotive engineering. In this paper, the authors manipulated the composite C-compression springs as a new trend of vehicle suspension system instead of coil or leaf springs. This type of springs can be safely and efficiently implemented in the vehicles' suspension systems and most probably be used in the new suspension design proposed earlier by one of the authors. Previous work on this context had shown a quality nature and economical technology in the use of composite springs in transportation and/or industrial applications.