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This study designs an adaptive integrated control. The control system includes two strategies of individual optimal linear quadratic regulator: one to improve vehicle maneuverability and another to improve vehicle stability. The integration is based on the vehicle dynamic variables in the phase plane. The controller can adapt itself by changing gains and integration law as vehicle mass and road friction change. The proper gains and integration law are determined for four special conditions: dry road-curb weight, dry road-gross weight, wet road-curb weight, and wet road-gross weight. These conditions are then expanded for every value of vehicle mass and road friction through fuzzy logic and Sugeno estimator. Simulation results show that considerable improvements are achieved in vehicle dynamic performance through the adaptive integrated control system. [ABSTRACT FROM AUTHOR]

The problem of controlling a string of vehicles moving in one dimension is considered so that they all follow a lead vehicle with constant time headway spacing between successive vehicles. Due to realistic design and execution, the negative effect of the tracking lag parameter and time delay is taken into account. By applying an acceleration feedforward, the distance error of each vehicle will be independent of the behavior of other vehicles. As a result, the vehicle is better able to track a desired trajectory, which improves the string stability. Cluster treatment of characteristic roots (CTCR) paradigm is utilized to reveal the stabilizing parametric regions in the domain of the time delay to render the stability of closed loop system. The string stability analysis is performed to evaluate the disturbance attenuation. Finally, an example of multiple vehicle platoon control is presented, which demonstrates the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Directional response and roll stability characteristics of a partly filled tractor semi-trailer vehicle, with cylindrical tank, under different parameters and conditions are investigated. The effective parameters and conditions in the stability of a tractor semi-trailer carrying liquid can be considered as filled volume, kinematic viscosity of liquid cargo and vehicle steering input. The dynamic interaction of liquid cargo with the tractor semi-trailer vehicle is evaluated by integrating a dynamic slosh model of the partly filled tank with five-degrees-offreedom of a tractor semi-trailer tank model. The dynamic fluid slosh within the tank is modeled using three-dimensional Navier-Stokes equations, coupled with the volume-of-fluid equations and analyzed using FLUENT software. The coupled tank-vehicle model is subsequently analyzed to determine the roll stability characteristics for different conditions and maneuvers. The results show effects of parameter variations on roll stability of the vehicle carrying liquid and also fluid's behavior in interaction with a vehicle's dynamics. [ABSTRACT FROM AUTHOR]

Road roughness is a broad term that incorporates everything from potholes and cracks to the random deviations that exist in a profile. To build a roughness index, road irregularities need to be measured first. Existing methods of gauging the roughness are based either on visual inspections or using one of a limited number of instrumented vehicles that can take physical measurements of the road irregularities. This paper more specifically focuses on the estimation of a road profile (i.e., along the 'wheel track'). This paper proposes a solution to the road profile estimation using a wavelet neural network (WNN) approach. The method incorporates a WNN which is trained using the data obtained from a 7-DOF vehicle dynamic model in the MATLAB Simulink software to approximate road profiles via the accelerations picked up from the vehicle. In this paper, a novel WNN, multi-input and multi-output feed forward wavelet neural network is constructed. In the hidden layer, wavelet basis functions are used as activate function instead of the sigmoid function of feed forward network. The training formulas based on BP algorithm are mathematically derived and a training algorithm is presented. The study investigates the estimation capability of wavelet neural networks through comparison between some estimated and real road profiles in the form of actual road roughness. [ABSTRACT FROM AUTHOR]

In this paper, an accurate and simple model of a satellite with two flexible solar panels for three-dimensional dynamic studies is proposed and compared with other models. In the proposed model, each solar panel is assumed to be rigid and attached to the satellite body via a simple hinge, a torsional spring, and a torsional damper. Kane’s method is utilized to derive the equations of motion. The model of flexible satellite with the assumption of Euler-Bernoulli beam for the solar panels, generally used in the literature, has been introduced for comparison. A comprehensive model of flexible satellite, considering solar panels as flexible and finite element panels, has been provided in ADAMS environment as a reference when comparing the two mentioned models. The Euler-Bernoulli model does not appropriately simulate the three-dimensional motion of satellite. Conversely, the hinged, rigid-panel model proposed in this paper provides suitable results in both two- and three-dimensional maneuvers. [ABSTRACT FROM AUTHOR]

The improvement of a vehicle body structure under the constraint of noise, vibration and harshness (NVH) behavior is investigated by using design of experiments (DOE) method. First, car body geometry is modeled in CATIA and meshed in HYPERMESH software. Then, a modal analysis between 0–50 Hz is done by MSC NASTRAN. A frequency map of the body is extracted and compared with a reference map to identify shortcomings. By using factorial and response surface Methods (RSM), optimization of the NVH performance is accomplished. An algorithm is proposed to improve the car NVH behavior. At last, in order to verify the present algorithm, forced vibration is analyzed under real road inputs for the model before and after improvement. [ABSTRACT FROM AUTHOR]