Showing papers in "Journal of the Society of Instrument and Control Engineers in 1979"

Non-Contact Rotational Speed Measurement and Integrated Spatial Filter Detector

Abstract: A new method is described for non-contact rotational speed measurement. It utilizes the natural irregularity of the surface pattern on a rotating object. The method employs an optical system and a spatial filter. The spatial filter is a radial array of photo-sensors having equal angular pitches. With this arrangement of photo-sensors, the filter acts as a narrow-bandpass spatial filter which generates a narrowband random signal whose center-frequency is proportional to the rotational speed. First, the spatial frequency characteristics of the spatial filter are analytically examined in the polar co-ordinate system. Next, a practical configuration of the measuring system is presented. In the measuring system, the spatial filter is realized by using a silicon solar cell of which the surface is etched to form the specially designed pattern. The experimental results showed that our method gave excellent characteristics in terms of accuracy, resolution and measuring range. Furthermore, the effects of measuring conditions are examined and evaluated, among which the effect of nonalignment between the center axis of spatial filter and the center axis of the projected image of the rotating object is not neglisible. It turnes out that this offcenter effect can be reduced if the parameters of the spatial filter pattern and the method of the center-frequency measurement are properly selected. 1. ま え が き

Basic Study on Discriminability of Mental Location of Electrocutaneous Phantom Sensation

Abstract: In this paper, in order to develop the spatial electrocutaneous communication system with minimum size of hardware, fundamental experiments were performed to provide with various locations on the skin a continuously variable sensation by utilizing the phantom sensation. Two sets of electrodes were located on the skin just above the biceps brachii and stimuli were presented to each electrodes either simultaneously or with time delay. The effect of relative magnitudes and time delay on the phantom sensation was experimentally studied. The following results were obtained. (1) The magnitude-difference cue was found more distinct than the temporal-difference cue. The phantom sensation caused by a magnitudedifference cue becomes less clear as the energy level becomes high (above 40 erg/channel), and as the interval of pulse stimuli becomes short (under 50ms). (2) The relation between the mental location of the relative magnitude phantom sensation and the ratio of the magnitude of stimuli E0/E1, in which E0 and E1 are the energy levels of stimuli simultaneously presented to adjacent locations respectively, is linear, and does not depend on the stimulus energy level (E0+E1) except in the vicinity of each electrode, where the relation depends on the energy level. (3) The just noticeable difference (jnd) of mental location has a maximum value at the central position between the two electrodes and a minimum value at the neighborhoods of the electrodes. The maximum information transmission rate calculated from jnd of mental location depends on the distance d between the two electrodes and ranges from 2.0 to 3.0 bits for d between 50 and 150mm. (4) The advantages of employing the technique of the phantom sensation are that it can reduce the number of electrodes required for spatial electrocutaneous stimulation and also that it can distribute stimuli more densely without the restriction of electrode sizes.

Prehension and Handling of Objects by Robot Hands with Redundant Fingers

Abstract: This paper describes the handling of objects by artificial fingers, when they include some extra fingers which are not always needed in a simple gripping. Firstly, the number of controllable finger forces and the handling forces to manipulate objects are compared, and the redundancy of the finger control system is defined. Next when the redundant fingers are contained, there exists some freedom to select the finger forces which generate the same handling force. We derive the optimal solution of finger forces by using pseudo inverse matrices. Finally, the experiments verify the theoretical results and the utility of the redundant fingers to handle objects.

On Bounds for the Solution to the Discrete Lyapunov Matrix Equation

Abstract: た だ し, A,Q∈Rn×n, Qは 正 定 対称 行 列, Aは 正 則 か つ|λi(A)|<1と す る. の 解 行 列Pの 適 当 な 尺度 に よ る “木 き さ”の 限 界 を, Q,Aな ど の “大 き さ” に よ り評 価 した もの で あ る. 連続 形 の リア プ ノ フ方程 式 に関 し て は, 同 様 の 趣 旨 の 報 告 がす で に い くつ か公 表 さ れて い る1)~5). 本 報 告 の 目 的 は, 離 散形 方 程 式 に対 して も連 続 形 方 程 式 に 対 す る結 果 と並 行 した 評 価 式 を得 て お くこ とに あ る. 以 下 で は, P,Qの 固 有 根 を順 に そ れ ぞ れ, 0<α1≦ ...≦ αn, 0<β1≦... ≦βnと し, 行 列X∈Rn×n(Cn×n)に 対 し て ||X||.で,・=1,2,∞な どの 適 当 な 行 列 ノ ル ム を 示 し, μ(X)を||X||. よ り 導 か れ た 行 列 メ ジ ャ ー7)と して u.[X]を 次 式 の よ うに定 め る. μ.[X]=max{-μ.(-X),-μ(X)} ま た, 行 列Aの ス ペ ク トル 半 径 を ρ(A)で 表 わ せ ば, ρ(A)<1で あ る.

Multivariable Control of Cold Tandem Mill

Abstract: The main function of the control system of a tandem cold-rolling mill is to produce the strip with a prescribed thickness accuracy and to maintain the interstand tensions within a a reasonable range in the rolling operation, against disturbances such as the mill input thickness, the stand set-up error, the drift of ingoing strip hardness, the coefficient of friction and so on. In a conventional control scheme, the output thickness is controlled by adjusting the screw position, while the interstand tension is controlled by updating the roll speed. Since the output thickness is strongly coupled with interstand tension, it is natural to consider that the integration of thickness control and tension control will result in a better control performance. In this paper we demonstrate an integrated control scheme for output thickness and interstand tension using the modern state-space approach. A state-space model for 5-stand coldrolling mill is derived and an optimal feedback control law is calculated for this model, incorporated with an integral action to eliminate the tension off-set. The output thickness of the preceding stand is employed as a feedforward signal to update the screw position of each stand. Simulation results are exhibited in comparison with that of a conventional control scheme. It is concluded that our system demonstrates a better control performance over the conventional one. Moreover it suggests an approach for shape control by adjusting weighting matrices of the performance index.

Synthesis of the Longitudinal Control System of a Fully Submerged Hydrofoil Craft with an Auto-Pilot

Abstract: Speaking of a fully submerged hydrofoil craft, all the hydrofoils attached to the foilstruts of the craft body are fully submerged in the water, so that the disturbing wave forces acting on the hydrofoils are very small in their foilborne cruising compared with the forces on the surface piercing hydrofoils. Therefore, the fully submerged hydrofoil craft gives us a very comfortable riding. On the other hand, the hydrofoils have little to do with stabilizing the height above the water surface and the attitudes of the craft and hence, an autopilot system is needed to stabilize the height and the attitude of the craft. In the present paper, a synthesis method for the longitudinal control system of a fully submerged hydrofoil test craft with an autopilot is described. The test craft (displacement: 4.3 tons) has two flaps attached to the port and starboard fore foils and one flap to the after foil, The height and the attitude (pitch angle) of the craft are affected by the variation of each flap angle. Therefore, the dynamics of the longitudinal motion of the craft are described as a coupled system, which has two controllers (fore and after flaps) and two controlled quantities (the height and the pitchattitude of the craft). The longitudinal control system including the craft dynamics and the autopilot consists of a height control loop and a pitchattitude control loop. These two control loops are coupled together through the craft dynamics. The longitudinal control system is roughly studied first, assuming the system could be separated into two decoupled loops, and then studied strictly as a coupled system. By this method, it has been shown that the synthesis for the longitudinal control system of the fully submerged hydrofoil craft could be done efficiently, and also that the calculated results of this method coincide well with those of the sea-trials by the test craft.

Realization Theory of Discrete Time Systems

Abstract: In this paper, the general realization problem of discrete time systems including nonlinear, time-varying, and infinite dimensional systems is discussed. The general realization problem is stated as follows.“Given a black-box whose input values and output values belong to arbitrary different sets U and Y respectively, find a“Mathematical Model”of the black-box which fits to the input-output data.” Our“Mathematical Model”in this paper is a dynamical system. The definition of the