Junichi Hino

Active suspension of passenger cars using linear and fuzzy-logic controls

Abstract This paper presents an active suspension system for passenger cars, using linear and fuzzy-logic controls. The model is described by a nonlinear system with four degrees of freedom, subject to irregular excitation from a road surface. The active control is the sum of two kinds of control. The former is obtained by vertical acceleration of the vehicle body as the principal source of control, and the latter is obtained by using fuzzy-logic control as the complementary control. In the derivation of fuzzy control rules, linear combinations of the vertical and rotary velocities and displacements of the vehicle body are denoted as the input variables. The simulation results indicate that the proposed active suspension system proves to be very effective in the vibration isolation of the vehicle body.

A finite element method prediction of the vibration of a bridge subjected to a moving vehicle load

Abstract This paper is concerned with the analysis of dynamic deflection and acceleration of a concrete bridge which is subjected to a moving vehicle load. The bridge, to be constructed across the River Brahmaputra in India, consists of 20 main spans, and each main span is assumed to be double cantilever type with a small suspended span. The moving vehicle is modeled as one degree of freedom. The deflections and accelerations at specific locations on the bridge when the vehicle moves at constant speed are analyzed by using the finite element method.

Vibration analysis of non-linear beams subjected to a moving load using the finite element method

This paper is concerned with the non-linear vibration of immovably supported variable beams, in which the geometric non-linearity due to the axial force generated by stretching the middle surface is taken into account. When the beam is subjected to a moving load, the dynamic deflections of the beam are computed by using a Galerkin finite element formulation, and the time differential terms are integrated by using the implicit direct integration method. Three types of approximations for solving the non-linear problem are considered, in the first of which both the longitudinal deflections and inertia are considered, with only the longitudinal deflections being considered, and in the second neither the longitudinal deflections nor inertia in the third. The results obtained by using these non-linear models are numerically compared with that obtained by the linear model.

Active suspension of motor coaches using skyhook damper and fuzzy logic control

Abstract This paper is concerned with an active suspension system for motor coaches, using a “skyhook” damper and fuzzy logic control. The model treated here is described by a nonlinear system with six degrees of freedom, subject to excitation from a road surface. The active control is assumed to be a sum of the skyhook damper and the fuzzy logic control, and the control is determined from the view-point of ride comfort, minimizing a given performance index. The simulation results indicate that the proposed active suspension performs effectively when compared with other forms of control.

Vibration analysis of a non-linear beam subjected to moving loads by using the galerkin method

Abstract This paper presents the analysis of dynamic deflections of a beam, including the effects of geometric non-linearity, subjected to moving vehicle loads. The beam is assumed to be elastic and simply supported with immovable ends and the vehicles are assumed to be single degree of freedom spring-mass-damper. With the vehicles moving on the beam from one end to the other, the dynamic reflections of the beam and vehicles are computed by using the Galerkin method. Thus the dynamic deflections are assumed to be a set of time functions multiplied by approximate functions, respectively, and the time functions are numerically computed by solving the non-linear differential equations by the Newmark-β method.

Random vibration of a non-linear beam subjected to a moving load: a finite element method analysis

This paper is concerned with the random vibration of non-linear beams with variable sectional areas subjected to a moving vehicle load. When the track on the beam is assumed to have such irregularities, the dynamic deflections of the beams as well as the moving vehicle vary in a random fashion. The irregularity of the beam in the forward direction of the vehicle is assumed to be a Gaussian random process, and is expressed by a first order linear differential equation with white noise excitation. The longitudinal and transverse deflections of the beam are formulated by using the Galerkin finite element method, and the time evolutions of the means and covariances of deflections of the beam as well as the vertical deflection of the vehicle are computed by using the linearization technique and the implicit direct integration method. Numerical results are presented to compute the dynamic deflections with the forward velocity of the vehicle as a parameter.

Construction of an active suspension system of a quarter car model using fuzzy reasoning based on single input rule modules

This paper presents the construction of an active suspension system for a quarter car model using fuzzy reasoning. The active control is obtained as a weighted sum of the defuzzificated values of the outputs in single input rule modules, and is generated by using a pneumatic actuator. The experimental result indicates that the proposed active control is more effective in the vibration isolation of the vehicle body than the skyhook damper and passive controls.

Active suspension system of a one-wheel car model using fuzzy reasoning and compensators

This paper is concerned with the construction of an active suspension for a one-wheel car model by using fuzzy reasoning. The experimental model is approximately described by a nonlinear system with two degrees of freedom subject to excitation from a road profile. The active control at the suspension location is designed by using fuzzy reasoning based on single input rule modules, and it is constructed by actuating a pneumatic actuator with dead time. The performance degradation of the active suspension system due to the dead time of the pneumatic actuator is improved by inserting two kinds of compensators. The experimental result shows that the active suspension system with the compensators more improves the control performance than that without compensator.

Active suspension of a half car model based on linear control with dynamic absorbers

This paper presents an active suspension system of a half car model based on linear control with dynamic absorbers. The model is described by a nonlinear four degrees of freedom system subject to irregular inputs from a road surface. The active control is composed of a weighted sum of acceleration, velocity and displacement of the vehicle body at front/rear suspension locations. The dynamic absorbers are added to the wheel axles in order to decrease the suspension and the tyre deflections. The simulation results indicate that the proposed active suspension is very effective in the vibration isolation.

Prediction of chatter in high-speed milling by means of fuzzy neural networks

This paper develops a new method for predicting chatter vibration in high-speed end milling using a fuzzy neural network model. Firstly, an experimental system is established. The system consists of an NC jig grinding machine with control device, a force sensor, a charge amplifier, and an FFT (fast Fourier transform) analyser. Over 10 groups of the typical experimental data are obtained under different milling tool wear states and cutting conditions. Then, because the experimental system is a nonlinear dynamic system with some fuzzy factors and too complicated to simplify it into an exact mathematical model, it is substituted by fuzzy neural networks, which are trained by using the above data. Lastly, for verifying the effectiveness of predicting self-excited chatter with the above model, some more experiments are performed. The comparison between the calculated and experimental results confirms that the method proposed in this paper could correctly predict the chatter vibration in high-speed milling. Therefore, the models of the method are reasonable and practical, and the accuracy is very high, which is significant for grasping the stable domain of high-speed milling in both theory and practice.