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Technical Paper

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

2009-04-20
2009-01-1042
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

Modeling of Vehicle Drum Brake for Contact Analysis Using Ansys

2012-09-17
2012-01-1810
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

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

2018-04-03
2018-01-1402
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.
Technical Paper

Optimized Proportional Integral Derivative Controller of Vehicle Active Suspension System Using Genetic Algorithm

2018-04-03
2018-01-1399
Proportional integral derivative (PID) control method is an effective, easy in implementation and famous control technique applied in several engineering systems. Also, Genetic Algorithm (GA) is a suitable approach for optimum searching problems in science, industrial and engineering applications. This paper presents the usage of GA for determining the optimal PID controller gains and their implementation in the active quarter-vehicle suspension system to achieve good ride comfort and vehicle stability levels. The GA is applied to solve a combined multi-objective (CMO) problem to tune PID controller gains of vehicle active suspension system for the first time. The active vehicle suspension system is modeled mathematically as a two degree-of-freedom mechanical system and simulated using Matlab/Simulink software.
Technical Paper

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

2019-04-02
2019-01-0172
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

Dynamic Lively Model to Utilize the Resources in a Vehicle

2006-04-03
2006-01-0521
The work presented here is to develop a monitoring life mathematical model to manage periodically the operations job orders of vehicle service station. This period is occasionally an hour, a day or a longer period than that, and is normally determined by the service manager. Model parameters are changeable over these periods due to dynamic movable situation of a vehicle markets. The objective function is to maximize the total income from vehicles service operations at all considered conventional model or with self expert prognostic system by taken into account least stop of vehicles, while keeping in mind the satisfying the customer demands and the service quality. The decision variables indicate the number of various technical operations to be performed for different types of vehicles.
Technical Paper

Performance of Active Suspension with Fuzzy Control

2009-05-13
2009-01-1614
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

Injection Characteristics of Rapeseed Methyl Ester versus Diesel Fuel in Pump-Line-Nozzle Injection System

2008-06-23
2008-01-1590
The transformation of rapeseed oil into methyl ester through the transestrification process normally produce biodiesel fuel with kinematic viscosity almost double that of the commercial diesel fuel. The bulk modulus of biodiesel is also higher than that for the conventional diesel fuel. In this paper, the effects of the two physical properties on the injection characteristics of Rapeseed Methyl Ester (RME) are discussed. The injection characteristics considered here were namely; nozzle chamber pressure, needle lift, and fuel injection rate. The mutual effects of engine speed and delivery pipe length were also analyzed. A previously developed computer model was used to simulate the injection process of the conventional pump-line-nozzle injection system. An explicit finite difference scheme was adopted to solve the unsteady flow equation within the delivery pipe.
Technical Paper

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

2006-10-31
2006-01-3586
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

Influence of Active Suspension Preview Control on the Vehicle Lateral Dynamics

2007-05-15
2007-01-2347
The dynamics of vehicles became one of the most important aspects for current developments of electronically controlled steering, suspension and traction/braking systems. However, most of the published research on vehicle maneuverability doesn't take into account the effect of the dynamic tire load and its variation on uneven roads. Clearly, it was stated that using a suitable active suspension system could reduce this dynamic tire load. This dynamic tire load is playing a vital role as it is the major link between the vertical and lateral forces exerted on the road, which affects the lateral dynamics of the vehicle. In this paper, a practical hydro-pneumatic limited bandwidth active suspension system with and without wheelbase preview control is used to study its influence on the vehicle stability in lateral direction. The model is a longitudinal half car with four degrees of freedom.
Technical Paper

Road Humps Design Improvement Using Genetic Algorithms

2009-04-20
2009-01-0466
The number of speed humps (sleeping policemen) has seen a global increase in the last decade. This paper addresses the geometric requirements of these humps using Genetic Algorithms optimization techniques to control the speed, stability, and ride feel of the traversing vehicles. The interaction between road hump profile and the modeled vehicles (passenger and a two-axle truck) are studied with a dynamic model. The shape of the proposed profile is described by numbers of amplitudes of harmonic functions. The extreme acceleration of the drivers’ seats of the vehicles traversing the hump is set as multiobjective function for the optimization process, taking into consideration the road-holding ability represented by the tire lift-off speed. The results show that hump geometry can be improved while fulfilling the requirements of speed control and vehicle dynamic responses.
Technical Paper

Dynamic Modeling of Vehicle Gearbox for Early Detection of Localized Tooth Defect

2008-10-07
2008-01-2630
Dynamic modeling of the gear vibration is a useful tool to study the vibration response of a geared system under various gear parameters and operating conditions. An improved understanding of vibration signal is required for early detection of incipient gear failure to achieve high reliability. However, the aim of this work is to make use of a 6-degree-of-freedom gear dynamic model including localized tooth defect for early detection of gear failure. The model consists of a gear pair, two shafts, two inertias representing load and prime mover and bearings. The model incorporates the effects of time-varying mesh stiffness and damping, backlash, excitation due to gear errors and modifications. The results indicate that the simulated signal shows that as the defect size increases the amplitude of the acceleration signal increases. The crest factor and kurtosis values of the simulated signal increase as the fault increases.
Technical Paper

The Importance of Vehicle Gear Tooth Meshing Stiffness in Gear Tooth Damage Quantification

2008-10-07
2008-01-2631
The early detection of incipient failure in a mechanical system is of great practical importance as it permits scheduled inspections without costly shutdowns and indicates the urgency and locations for repair before a system incurs catastrophic failure. However, in this work a new technique for processing vibration data to quantify the level of damage, cracks only, in a gear system. The technique consists of a nonlinear numerical optimization. The optimization uses a dynamic model of the gear mesh used in vehicle gearbox and forms an estimate of both time-varying and frequency-varying mesh stiffness that best corresponds to the given set of vibration data. The procedure developed in this study can be applied as a part of either an onboard machine health monitoring system or a health diagnostic system used in the regular maintenance.
Technical Paper

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

2006-10-31
2006-01-3515
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

2006-10-31
2006-01-3467
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

New Suspension Design for Heavy Duty Trucks: Design Considerations

2003-11-10
2003-01-3428
The present paper presents design considerations for a new tandem suspension system equipped with hydro-pneumatic components. The theory of the new suspension and its configuration were presented in a previously published SAE paper, [1]. In this design, most of the vertical motions were transformed into horizontal motions through two bell cranks. A hydraulic actuator is installed horizontally between the bell cranks and connected to an accumulator (gas spring) via a flow constriction (damper). Incorporating of hydro-pneumatic components in the new suspension system exhibits simple and applicable design. Moreover, further developments including active or semi-active vibration control systems, can be applied directly using the existing hydro-pneumatic components. Mathematical models are constructed to simulate the vehicle ride dynamics. Equations of motion are generated considering a conventional passive suspension (four springs tandem suspension) and the new designed suspension system.
Technical Paper

Theoretical and Numerical Analysis of Fibrous Composite C-Springs

2001-11-12
2001-01-2710
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.
Technical Paper

Aerodynamic Effects on Ride Comfort and Road Holding of Actively Suspended Vehicles

2002-07-09
2002-01-2205
This paper is concerned with the analysis of the performance of actively suspended vehicles when the effects of the aerodynamics are considered. The investigation is wholly theoretical and treats a half vehicle model, active suspension, through simulation of running at different speeds on a random-profile road. Using classical control laws, which do not account for aerodynamic effects, it is shown that starting from a vehicle speed of 35 m/s, ride comfort and road holding parameters significantly deteriorate. A method is introduced to modify the control strategy so that these effects can be taken into consideration. Various forms of control laws are presented, and conclusions are drawn to specify the benefits that could be achieved from this modified control strategy.
Technical Paper

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

2019-02-05
2019-01-5006
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

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

2014-04-01
2014-01-0864
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.
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