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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.

Magnetorheological (MR) fluid dampers are the most promising devices for practical vibration control applications because they have many advantages such as mechanical simplicity, high dynamic range, low power requirements, large force capacity and robustness. This paper aims to study the dynamical behavior of a linear MR fluid damper through experiments. Also, an efficient and simple model is developed to identify the damping force as a function of the damper velocity, acceleration and applied voltage to the magnetic coil, without using any complicated mathematical or differential equations, which will be very useful for large and complicated applications. The identified parameters of the MR damper are obtained using trial-and-error methodology. The validation is done using the dynamical behaviour of MR damper for both experimentation and simulation, by solving the modified Bouc-Wen (M B-W) model that can predict the dynamical behavior of MR dampers accurately.

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.

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.

Heavy trucks are becoming more common in use for international transportations, with longer highways and long driving hours contributing corresponding increases in driver's fatigue that is related to accidents. In this paper a detailed procedure is proposed to improve a highway truck seat. A dynamic model of an on-highway truck seat is simulated using Simulink toolbox in MATLAB. The seat suspension including the cushion is mounted on the cab floor of a half truck model and excited by a rapid excitation of step input. The seat suspension system controller is designed to improve the ride quality of the driver. Genetic Algorithms (GA) is used to obtain the coefficients of the control parameters. In addition, model outputs comparison of the proposed design to a conventional passive seat suspension using the maximum overshoot and the root mean square (RMS) values of both, the driver acceleration and the seat suspension working space.

In this paper, the performance tradeoffs in the design of electronically controlled suspension systems are theoretically studied. Using quarter car model, a new treatment procedure for the control laws is introduced using fully active suspension system with two control strategies. The first strategy is considered for vehicle vibration isolation due to random road excitation only. The second strategy is considered to perform a zero steady-state suspension deflection due to body vehicle attitude variation during maneuvering, braking and aerodynamics as well as vibration isolation due to random road excitation. The two strategies are achieved by using two different optimization techniques combined with PID (Proportional-Integral-Derivative) compensator. The first technique is based on Linear Quadratic Regulation (LQR) technique and the second technique is based on Genetic Algorithm (GA).

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.

Road humps are considered as one of the best design propositions to control running vehicle speeds, in many roads they are randomly installed depending on the resident's requirements. In this paper, Genetic Algorithm (GA) optimization technique is used to design an active suspension based on force cancellation concept when the vehicles crossing road humps. A longitudinal half vehicle model is used to represent passenger's car and truck models. These models are used to evaluate the performance of active suspension over the road speed humps. The force cancellation concept is employed to isolate the force between the sprung and unsprung mass. Virtual damper and skyhook damper concepts are also used for reducing the sprung mass acceleration and tire dynamic loads. GA is adopted to obtain the better coefficients of a virtual damper and a skyhook damper for its effective searching ability.

Vibration ride comfort of combat vehicles is essential subject because these vehicles operate at different environments. Improving the comfortability enables the solders to drive for a long time at critical situations with full activity. This paper looks at the ride performance of multi-axles combat vehicles driven at varies speeds over terrain profile. Three configurations of these vehicles, two axles, three axles and four-axles-vehicles, have been studied and compared. The results showed that at a wide range of speeds there is a significant improvement to be gained by using four axles over the three axles and two axles when emphasis is placed on the vehicle body vertical acceleration and dynamic tyre loads.

In this work, the active front steering control is studied using linear three degrees of freedom handling model incorporating the driver’s operation model and vehicle suspension derivatives. The active steering control strategy is based on the optimal control theory. In this design, the active front steering angle is determined based on minimizing all model state variables and full state feedback gains. The results are generated when the model is excited by random wind excitation, which was modeled as quasi-static approach with statistical properties taken from previous work, and presented in frequency domain as power spectral density as well as root mean square values in tables. Significant improvements are achieved for the vehicle handling characteristics using active front steering control in comparison with active four wheel steering and conventional two wheel steering.

In this paper, the Kalman filter algorithm is used to design a practical adaptive control strategy. The adaptation is intended to adjust the system operation according to the changes of road input. A moderate adaptive time of at least 3 seconds is used. Limit stops are added to prevent the increase in the wheel travel behind the specified limit. The active suspension feedback system is designed based on measuring only the suspension displacement. A gain scheduling adaptive scheme which consists of four sets of state feedback gains is designed. The estimation process of dynamic tyre deflection and other necessary state variables through the Kalman filter is illustrated. Among other things, this estimate is used to derive the gain scheduling adaptive scheme. The strategy is applied to a quarter car active suspension system. Results are generated at a constant speed on random road profiles.

One of the main causes of the torsional and bending fluctuations of the driveline is the angularity of the driveshaft and its universal joints. Most of the previous studies of the driveline vibrations have considered constant and equal angularities of these joints. However, the exact equality of the angularity is very difficult to maintain for ground vehicles under different ride vibration modes. This paper is concerned with the coupling between the driveline fluctuations and the ride vibrations of the rear drive vehicles. The coupled motions, which are; drive axle suspension deformation and vehicle body pitch angle and their derivatives, have been used to study the driveshaft and output shaft bending and torsional fluctuations. The results have showed that the fluctuations of the driveshaft due to the base angularity of the joints are superimposed by another fluctuation due to the bounce and pitch of the vehicle body.

In this paper, a continuously controlled semi-active suspension system is designed for trucks main suspension. Using a linearized seven degrees of freedom mathematical model equipped with hydraulic and hydro-pneumatic components, the optimal damping forces for truck front and rear suspensions are designed based on optimal control theory using Linear Quadratic Regulation (LQR) to improve the ride comfort and dynamic tyre loads. The practical limitation for the damping forces and the time lag for system controllable elements are taken into account. The results are generated considering the suspension components non-linearity and the model is excited by statistically random road. The frequency domain results as power spectral density and the root mean square values are compared with those obtained from conventional passive suspension system.