Order Lag System Research Articles

1P2-J06 視覚誘導性身体動揺の2次遅れ系モデリングにおけるパラメータ同定手法の構築とモデル検証

The physical movements called visually induced postural sway are occurred when humans get visual stimuli. In this study, modeling and the model parameters identification in this phenomenon using second order lag system have been discussed. Based on the results of time- frequency analysis of actual human behaviors, identification procedure of these parameters are considered from the viewpoint of the relations of several characteristics of human behavior and model; Gain and the maximum postural sway, natural angular frequency and the frequency component contributed to induction by visual stimuli, damping coefficient and the decreasing of postural sway after. As the results validity of second order lag model using identification procedure has been confirmed.

Measurement and analysis of the shape recovery process of each erythrocyte for estimation of its deformability using the microchannel technique: the influence of the softness of the cell membrane and viscosity of the hemoglobin solution inside the cell

This study tried to evaluate the deformability of each erythrocyte by measuring the time constant of shape recovery just after the erythrocytes left the microchannels. We fabricated a microchannel array with a 5μm-square, 100μm-long cross-section on a PDMS sheet. Three different kinds of blood samples were prepared—healthy erythrocytes as a control, artificially membrane-hardened erythrocytes and artificial hemoglobin solution-diluted erythrocytes—to investigate the influence of erythrocyte's mechanical property changes on the time constant of shape recovery. These shape recovery processes were modeled and analyzed by a standard liner solid model. As a result, the temporal variation of the compressive strain of all erythrocytes showed exponential decay with time elapsed like a first order lag system, so the time constant of shape recovery could be calculated from the semi-logarithmic relaxation curve. The stiffer the cell membrane was using glutaraldehyde, the shorter the time constant for relaxation became compared to healthy erythrocytes. The diluted hemoglobin erythrocytes snapped back quicker than healthy ones. In addition, the time constant of healthy blood drawn from females was clearly shorter than that collected from males. However, the time constant of fully hemoglobin substituted erythrocytes was not affected by gender difference. These results indicate that there is not a significant difference in the stiffness of healthy cell membranes regardless of individual and gender differences. On the other hand, the viscosity of the hemoglobin solution inside the cell is one of the significant factors affecting the time constant. Therefore, these results suggest that the deformability of individual erythrocytes can be quantitated by the time constant for relaxation measured by microchannel techniques.

Guidance Synthesis to Control Impact Angle and Time

A new guidance synthesis for anti-ship missiles to control impact angle and impact time is proposed in this paper. The flight vehicle is assumed as a 1st order lag system to consider more practical system. The proposed guidance synthesis enhances the survivability of anti-ship missiles because multiple anti-ship missiles with the proposed synthesis can hit the target simultaneously. The control input to satisfy constraints of zero miss distance and impact angle, and the feedforward bias control input to control impact time constitute the guidance law. The former is from trajectory shaping guidance, the latter is from neural network. And particle swarm optimization method is introduced to furnish reference input and output for learning in neural network. The performance of the proposed synthesis in the accuracy of impact time and angle is validated by numerical examples.

COMMAND GUIDANCE SYSTEMS SIMULATION : AIRFRAME ANALYSIS

A complete six-degrees of freedom flight simulation model for anti-aircraft command guided missile system is developed. A computer code that solves the model is constructed with BORLANDC. Modular concept is considered in the code development. The non-linear differential equations that describe the model are solved by Runge-kutta 4 method. The integration step is chosen small enough that the numerical errors are negligible. The aerodynamic non-linear coefficients that describe the missile airframe are calculated by the aid of standard NASA curves. The missile is roll angle stabilized throughout the flight. It is controlled in the lateral planes via two pairs of rear control fins. The pitch and yaw control channels are identical except for constant gravity bias added to the pitch channel. The missile airframe is deeply investigated. The step response of the airframe to unit step fin deflection is obtained. The results indicate that the airframe can be accurately represented by a second order lag system. The weathercock natural frequency and the damping coefficient are obtained by transforming the time-domain data to the frequency domain by the Fast Fourier Transform. The obtained results show that the missile airframe is heavily underdamped. As well, the airframe bandwidth increases by increasing the missile speed. Doubling the missile speed fairly doubles the weathercock frequency at the expense of aerodynamic damping coefficient reduction.

力支持制御される被衝突体を含む振動系の繰返し衝突動作 フォロアが１次遅れ系の場合

Vibration with collision has widely utilized on industrial techniques, especially in the fields of impulsive working, impact machining and parts assembly, because its generated impact force has impulsive property, the very high peak and a short impact time. Hence, a tool can easily work with very high level of the force in the working, and parts can be given a positioning of the high accurate resolution to the specified position by the force which can be easily over the maximum friction force and can't move only the short distance according to the short impact time. The impact is generated between an impacter of one degree of freedom vibratory system and the impact follower of the first order lag system with a mass and a damper. The paper deals analytically with characteristics of a steady-state repetitive impact motion which has the period agreed with one of a harmonic excitation force for many industrial utilities. The impulse, impact intensity is proportional to the pressure force level required to support the follower. In the specified condition, the modal of the impacter approaches that of an impact system having a rigidly fixed follower, a wall.

Improvement of Control Performances for Low-Dimensional Number of Fuzzy Labelings. (Using Fuzzy Control Simulator).

Recently fuzzy control has been recognized to be of great usefulness in many engineering fields. However, the adjustment of fuzzy control parameters such as control rules, membership functions has been carried out by trial and error, and the definite design method of fuzzy control systems has not been established yet. In this paper, the influences of fuzzy inference methods on control performances have been examined by the simulations of a first order lag system with dead time. Moreover, the improvement of control performances in case of low-dimensional number of fuzzy labelings has been tried. Main results are as follows : (1)When the number of fuzzy labelings is low-dimension such as 3×3 divisions, control performances are dependent on fuzzy inference methods. Therefore, in case of low-dimensional number of fuzzy labelings, the selection of fuzzy inference methods is important. (2) Even in case of low-dimensional number of fuzzy labelings such as 3×3 divisions, by using the simple method of changing the height of the consequent membership function ZO, the non-linear characteristic of a fuzzy controller can be tuned and its control performances can be improved.

Model Following Control of Hybrid 4WD Vehicles

This paper presents a method to design a rear wheel torque control system for hybrid four wheel drive vehicles (H4WD) and the results of its construction to an experimental vehicle. In the H4WD the front wheels are driven by an engine and the rear wheels are independently driven by two motors. The rear wheel torque control system employs a model following approach in which the yaw rate of the vehicle is controlled to track a reference yaw rate. The reference yaw rate is produced from a yaw rate reference model, a first order lag system which has a steering angle as the input signal. From results of computer simulations and experiments, this control system has been found to decrease the deflection of the vehicle due to lateral force disturbance such as lateral wind gusts. It also improves both the stahility and the controllability of the vehicle.

High speed and accurate computing method for the simulation of laminar transient flow in rectangular duct by characteristics method.

The frequency-dependent friction in transient laminar pipe flow is given by the convolution of the weighting function with the past velocity changes. But in the case of a rectangular duct, it is difficult to obtain the weighting function because of a very slow convergence. In this paper, the fundamental formula of the instantaneous wall shear stress is developed into a series on the Laplace region, so that the weighting function is estimated very easily. And an accurate and efficient approximation to reduce the computation time is developed for simulating the frequency-dependent friction in the method of characteristics. This method consists of approximating the weighting function as as sum of the impulse responses of a first order lag system. By this new method, the water-hammer phenomena can be calculated precisely with little computation time. The validity of this method is certified by comparison with the experimental result.

LOAD-SENSING DYNAMICS OF APRESSURE-COMPENSATED VARIABLE DISPLACEMENT VANE PUMP

The present report deals with an analysis of a pressure-compensated variable displacement vane pump regarded as a load-compensating control system. On the basis of experimental data of an article on the market, the effective transfer function of he mechanical system can be reduced to a form of 1st order lag system. Furthermore including the pressure surge in actual circuits due to the sudden change of the oad flow into the analysis, it becomes clear that the entire transfer function of the mechanical and hydraulic system has a form of phase lead system. The theoretical solution of the step response of the output pressure is similar to the experimental data. After the consideration of effective parameters in the entire system based on he above results, several guides for parameter design are to improve the load-sensing function and to optimize its step response.

試験信号を用いた適応制御装置

This paper presents a method for self-adjusting the parameters of a control system using a sinusoidal test signal. In this method, the frequency of the test signal is automatically adjusted to have 180° phase lag in the control loop, and the proportional sensitivity of the controller is adjusted to keep the gain of the test signal constant at this frequency. The integral and derivative time of the controller are also adjusted to have a fixed relation to this frequency.This system has two self-adjusting loops, each for adjusting frequency of the test signal and for adjusting proportional sensitivity of the controller. The dynamic behaviors of these loops are equivalent to that of the first order lag system, and the increase in the speed of response of the loop is obtained by increasing the amplitude of the test signal.The dynamic error in the parameter adjustment in this system depends on the spectral density of the process noise at the frequency of the test signal. For detecting the signal component in the control system output which contains the signal and noise, a simple demodulation technique which cross-correlate the sign of this output with a known sinusoidal signal, is proposed in this paper. It is shown that by the introduction of this technique, the dynamic characteristics of the self-adjusting loops are improved.Experimental results of this method applied to a flow control system are also shown.