This paper describes a new fuzzy neural network (FNN) controller in which a Gaussian function is applied as an activation function, referred to here as a fuzzy Gaussian neural network (FGNN) controller. The learning architecture adopted is specialized so that we can tune the membership functions without using an expert's manipulated data. As an example of application, a tracking control problem for the speed and azimuth of a mobile robot driven by two independent wheels is solved using the FGNN controller. In order to facilitate the application of an FGNN controller to multi-input multi-output systems, we then propose a learning controller consisting of m FGNNs based on independent reasoning and a connection network, where m denotes the order of output of the control object. The effectiveness of the proposed method is illustrated using computer simulation.

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Recurrent neural networks have dynamic characteristics and can express functions which depend on time. We can apply the recurrent neural networks to robotic motions. For this purpose, it is necessary to determine interconnection weights of the network. Formerly, the learning algorithms based on gradient techniques were shown. However, it is difficult for the recurrent neural network to learn such functions while using previous approaches through time because of computing requirements and the limitation of memory. This paper presents a new learning scheme for recurrent neural networks by the genetic algorithm (GA). The GA is one of the search algorithms based on the evolution of creatures. For learning in the recurrent neural networks, the GA is applied to determine interconnection weights of the networks. The GA approach is compared with the back-propagation through time which is a famous learning algorithm for recurrent neural networks. Simulations illustrate the performance of the proposed approach.

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We present a new control method for an active mass damper. Conventionally, a pole assignment method and Linear Quadratic control theory are used for designing the controller of the active mass damper. However, these design methods are not convenient when output of the actuator and movement range of the damper mass is limited, because they cannot restrict any variable directly. Hence, we propose to determine the reference orbit of damper mass first, and control damper mass by a learning controller using the neural network. Our method can keep a mass damper with in a designated range. The performance of our method is better than that of LQ controller in settling time. To show the effectiveness of our method, we apply it to control of an active mass damper for an elastic arm which is a one-degree-of freedom structure. Moreover, we control the experimental system using a neuralnetwork which is learned in a simulation environment.

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In this paper, we discuss the application of the extended Kalman filter algorithm to the training of neural networks for pattern recognition and pattern formation. In neuron training, we use our acceleration technique, i. e. the VC technique, introduced in the first report. It is shown that the relationships between the dot pattern of the letter symbol and the binary code of the symbol are constructed effectively in both networks. Finally, it is also shown that pattern association from the incomplete pattern is realized by connecting the above two neural networks.

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Cooperative manipulation by autonomous intelligent robots have good potential for improving the ability of robotic manipulation and expanding the domains where the robot may be used. This paper focuses on the method for searching proper desired force of each robot based on local sensor feedback and heigh level communication. First, we propose the adaptive force direction control, which is useful for monitoring the state of force equilibrium, and describe the theoretical background of this control method. Second, we describe the strategy for searching proper desired force using proposed control method and heigh level communication. We also describe a control system architecture which is suitable for these operations. In this control system, each manipulator motion function, each sensor function and each message passing operation are programmed as primitive tasks which run in parallel. Third, we illustrate the usefulness of proposed method with some experiments of tumbling operation by two autonomous robots.

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This paper discusses the identification of unknown parameters, such as external force and contact points by adding such redundant non-active joints as detecting only torque to a hand. Multi-fingered hands tend to have an unstable grasp because of their many degrees of freedom. But the grasp can be readily stabilized by a method which allows one to set the three-dimensional internal stiffness at each fingertip. Thus, when an unknown object is grasped stably, it is considered that the grasp can be made more stable if unknown parameters can be identified using data obtained during the initial grasp. It is shown that unknown parameters can be identified by adding redundant non-active joints detecting only torques to a hand. Finally, it is illustrated by simple two- and three-dimensional examples that the proposed identification algorithm of the grasping parameters is valid.

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This paper deals with the problem of optimizing the behavior of a group robotic system, such as the Cellular Robotic System, in dynamic environments. The Cellular Robotic System (CEBOT) is an autonomous distributed robotic system composed of a large number of robotic units called "cells". Since the CEBOT is a group robotic system, cooperation and group organization are required for task execution. In this paper, We propose the concept of the "self-recognition" of the decision-making in the group behavior. To make a decision, each autonomous robot constructs an inner model based on the recognition of environment and the robots' state. If each robot behaves based on the inner model, which is constructed without consideration of the group behavior in the group system, deadlock problem will occur. Therefore, each robot is required to consider the influence of self-action on other robots and group system. The concept of the "self-recognition" is derived from consideration of this influence. We propose the learning and adaptation strategy for group behavior based on the concept of "self-recognition" and show its effectiveness through the simulation results.

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The robot navigation problem is becoming one of the most important Problems that must be solved as automated and flexible manufacturing techniques become more advanced. This problem arises when a simulated robot searches for an optimal path from a given starting position to a destination position while avoiding the obstacles for an arbitrary navigation task. In particular, the difficulties of this problem are compounded in a multiagent environment in which there are many robots, each having individual navigation tasks in the same navigation area concurrently. In this paper, a new approach to the autonomous solution of the robot navigation problem is proposed. To realize an autonomous robot navigation mechanism, we applied a classifier system. This is a machine learning system in which simple string rules are learned to improve the performance in an arbitrary environment. Thus, each agent has its individual classifier system and searches for an individual solution with interaction among agents. Based on the proposed method, a robot navigation system was constructed and numerical experiments were carried out. The results of these experiments demonstrate the usefulness of the proposed method.

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In this paper, we aim to solve the obstacle-avoidance problem using the vibrating potential method (VPM). The obstacle-avoidance problem is famous inthe field of a navigation of automatically guided vehicles (AGV). There are many kinds of behavior for a group of AGVs such as forward and backward movement, rotation, fission, fusion, avoidance of obstacles and passing through free-form narrow paths. Since these types of behavior are capable of changing according to the environmental surroundings of the AGVs or their goals, the problem can be described using three systems : "Obstacles, " "AGVs" and "Goals". For this problem, we use the VPM to obtain a strategy for achieving a goal for each AGV. In the VPM, an environment is constructed by means of a wave motion propagated from the obstacles, AGVs and goals. These subsystems of the obstacle-avoidance problem system interact with each other through the information from the detected wave motion from the environmental surroundings. Using a VPM, each AGV can decide upon its movement through detection of wave motion from the environment surroundings without specific problem-oriented programming. Furthermore, the movement of a group of AGVs is represented in computer simulations for such situation as approaching behavior for each goal, avoiding obstacles and fission and fusion behavior.

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Two methods have been developed for real-time identification and classification of the roughness patterns of road surfaces using the neural network. These methods are applicable to both semi active and active vibration controls of cars. Accelerations of the rear wheel axis with suspension are used as input data for real-time identification. A neural network based on the seven typical roughness patterns is used for real-time classification of actual road surfaces during driving. Validity and usefulness of these methods are verified by simulation.

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Quadruped walking animals can walk smoothly and they change their walking manner according to the walking speed. Since this motion is governed by the nerve center, it is automonous and natural. In this study we attempt to construct a new controller for walking robots, which realizes natural walking such as that of animals. The controller consists of a central rhythm generator and a distributed controller attached to each leg. The distributed controller can drive each leg automonously and synchronize it with the other legs. Moreover it automatically realizes a suitable gait according to the walking speed.

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The authors have investigated a parallel bicycle-type mobile robot which has a controlling arm and a working arm. In the previous papers, control methods for postural stabilization and several kinds of motion and experimental results for this vehicle were reported, in which basic movements including driving, standing up and falling down as well as use of working using the working arm were shown. However, the working capability was insufficient because the former working arm was constructed of only one link. In this study, a new type of vertical two-link working arm constituting of an overarm (first link), forearm (second link) and hand (gripper)was developed. A newly devised double-clutch mechanism is installed on the joint between the overarm and the forearm. It can be switched using wire actuators made of shape memory alloy (SMA). With the use of the clutch, rotation of the forearm and the hand is realized by switching the electric current provided for the wire actuators. Gripping motion of the hand is also attained by use of another SMA wire actuator. With the three kinds of wire actuator, we developed a lightweight working arm. This paper describes mechanisms of the working arm and motion control methods. Experimental results for motion using the working arm and postural stabilization of the robot by the controlling arm are also given. It is confirmed experimentally that the inverted pendulum-type mobile robot with the working arm developed in this study shows potential for use in the new automonous land vehicle.

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In this paper, we report dynamic characteristics of power assist circuits made with artificial muscle. This power assist circuit may be useful for handling human beings in hospitals. Previously, we presented a nonlinear dynamic model which describes the compressibility of air, and volumetric change characteristics of artificial muscle. In this paper, the linear model is derived from the nonlinear model using the linearization technique, and the effectiveness of the linear model is shown. Differences in the characteristics when the power assist circuit is driven by two different types of pneumatic servo valves are recognized. By experiments, servo valve flow rate characteristics are found to be quite important in system dynamics and system stability is improved by using a digital control algorithm. The characteristics of the power assist circuit are analyzed using the linear model. We found the pressure-flow gain for power assist circuits can be calculated by using this model.

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The development of an actuator system that is robust with varying load is strongly required. This paper proposes a basic and simple control method that makes it possible to obtain constant output characteristics from the actuator even when the load is changed. An actuator is considered to be an energy converter where input and output of energy consists of two variables, across variable and through variable, and the actuator is modeled to have a power source and internal impedance/admittance. If we can control the internal impedance/admittance to be zero, the whole of the power that is input will be fully output. Actually, we cannot change the internal impedance/admittance of the actuator itself, but applying this theory to the actuator control system, we can minimize the apparent internal impedance/admittance and make the output characteristics constant. The concrete implementation using a brushless dc-type DD motor is reported, and the effectiveness of this system is confirm by experiment and simulation.

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Robotic manipulators are generally controlled by individual articulation of each robot. Thus, robotic operations defined by working coordinates must be translated into articulation coordinates for each robot. This translation from working coordinates to articulation coordinates generally requires solution of inverse kinematics of the robot. However, the inverse kinematics of the robot sometimes cannot provide a solution due to its complexity. This paper shows a new method for controlling the robot using the solutions of repeated direct kinematics instead of inverse kinematics of the robot, and shows that the solution of repeated direct kinematics is equivalent to the solution of the inverse kinematics of the robot. Furthermore it is also shown experimentally that this method is applicable to the control of position and force of the robot.

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A simple torque sensor for a tendon-driven manipulator is proposed. The finger joint torque around a drive pulley is proportional to the tension difference on both ends of the pulley. With a coupling mechanism between tendons, this tension difference can be measured directly without detecting individual tendon tensions. The tension differential-type torque (T.D.T.) sensor is based on this idea and is useful for compensating for friction existing in the transmission system of the manipulator. However, so far, the T.D.T. sensor needs at least one tension pulley to support a driving tendon. This paper shows that it is possible to design a T.D.T. sensor without any tension pulley maintaing its basic principle. A torque sensor installation on the movable link makes it possible to eliminate the tension pulley and downsize it.

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Rationalization for a container yard is achieved through the automation of both container yard management and handling machines, in which the automation of container cranes, has developed to correspond to the so-called IVth-generation container crane. However, the automation of container cranes has been mainly achieved slmost only about antisway control up to this time. We have developed the total automation system which works under the scheduled handling order given from the upper level computer. The system has such functions as not only antisway control but also positioning control, optimum route control, container stacking profile recognition, and management of operation. This paper explains the automated container crane system within the total management system of a container yard, and also proposses our policy for this in the future.

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In this paper, we describe a new method for analyzing nonlinear vibrational properties of rubber using experimental results of a dynamic hysteresis characteristics test of rubber vibration isolators used in automobiles. This method was developed based on an equivalent linear system using the restoring force model of power function type. As a result of our studies, we are now able to determine the vibrational properties of rubber (dynamic spring constant and damping factor) in relation to frequency and amplitude of displacement. That is to say, we devised a theory of simulation that enables one to predict the vibrational properties of rubber using the area of the hysteresis loop and bone curve.

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Free vibration of string with time-varying length is analyzed. An equation of motion described by a partial differential equation cannot be solved by the method of variable separation. In the present paper the equation of motion of a string with a constant length is described by a partial integro-differential equation. Then, vibrations with a moving support acted upon by an unknown load are analyzed. From the condition that the displacement of the string at the support is zero, an integral equation of Volterra type of the first kind with respect to an unknown load is obtained. This integral equation is solved approximately and solutions of free vibrations are obtained.

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Free vibration of a string with time-varying length is analyzed. An equation of motion cannot be solved by the method of separation of the variables because the length of the string varies with time. New variables of position and time are introduced, and then the equation of motion which can be solved by the method using a hypergeometric differential equation is obtained. Exact solutions of free vibration are obtained by Laplace transformation.

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In this paper, we consider the characteristics of a nonlinear vibrating system, i. e., the van der Pol and Duffing equation, with a retarded argument under a harmonic exciting force. A numerical analytical procedure has been applied to analyze the characteristics in the subharmonic resonant region of the system. The system has been found to show quite complex charachteristics, e.g., many kinds of subharmonic oscillations, both symmetric and asymmetric subharmonic solutions, difurcations and nonperiodic solutions. Each of these subharmonics has shown isolated, island like response curves. With the use of numerical simulation, Poincare mapping, basin of attractions and chaotic phenomena, corresponding to nonperiodic solutions, have been obtained. The chaotic behavior appears in various frequency regions. These nonperiodic motions have been concluded to be chaotic because of the positive Lyapunov exponent. The route to chaos is via period doubling bifurcations.

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A new technique for dynamic system identification using a stochastic time series model such as the AR model or the ARMA model, is proposed and investigated. After demonstrating the advantage of these methods over former major identification methods based on FFT, this paper focuses on a double variate AR model method which can be developed to identify nonlinear dynamic systems. Here the dynamic characteristics are evaluated in the form of equivalently linearized system parameters. As a typical example, a simple nonlinear system having a bi-linear stiffness characteristic is adopted. Through numerical simulation for the model, the validity and applicability of the method to such a nonlinear system are examined.

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Vibration control of a pendulum is studied by actively changing the Vertical position of its hinge. The pendulum is hinged to a truck in a vertical linear way. The truck is moved vertically by means of a belt, two pulleys and a DC servomotor. The motions of the truck and pendulum are governed by a bilinear form of the state quantities. On the basis of control theory of the bilinear system, the motion of the pendulum is controlled and stopped quickly. The theoretical results agree well with the experimental ones, taking the friction of the hinge into consideration.

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This paper describes the new elasto-plastic damper, named the LED-rotary-type damper, This damper contains lead as an energy-absorbing material. The damping force is generated from the plastic shear deformation at the top of the projections arranged on the swing shaft. Then, experimental devices with the rated damping force of 4.9, 9.8, 14.7, and 98 kN were manufactured on trial and examined to elucidate the fundamental characteristics. In these results, this damper has favorable characteristics such as dependance on low velocity, relaxation and durability of the damping force. From this point of view, this damper is more suitable for use in vibration control in comparison with other elasto-plastic dampers.

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Recently, very fast motion has become necessary for mechatronic devices such as industrial robots and thus, an optimization method for the velocity driving pattern of the moving body is indispensable. We propose indexed sinusoidal curves as the driving curve θ and achieve reduction of the motion time by considering factors such as the motor torque-velocity characteristics. θ = θ_m sin^m(2πt/t_h) In this paper, the characteristics of indexed sisusoidal curves and the optimization method for the driving pattern are presented. Next, its application results for a single-joint mechanism are described and the effectiveness of this method is confirmed.

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To improve the riding comfort of a heavy duty truck, it has become popular to adopt a leaf spring with a low spring constant and low damping coefficient. Consequently, the brake-hop phenomena can be observed in heavy duty trucks. These phenomena are extraordinary vibrations of the unsprung mass of the suspension system under the application of a hard brake. Theoretical analyses are performed for obtaining the criteria for the brake-hop using a simple two degrees of freedom dynamic model with nonlinear frictional force. The obtained criteria show that the phenomena of the brake-hop are self-excited vibrations induced by the negative damping components of friction between tires and the road surface, and that they appear when the negative damping of the friction is greater than the positive damping of the suspension system. The analytical results are confirmed by the experiment with the use of an actual heavy duty truck.

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Pressure-conductive rubber has many excellent features such as high Flexibility, workability and ease in the fabrication of thin films. However this material shows hysteresis between pressure and resistance values. To date, this property has not been investigated in detail. In this paper, evaluation of pressure sensing characteristics of pressure-conductive rubber, including hysteresis, time response and creep effect, was carried out. A pressure loading instrument in which motion could be precisely controlled was constructed to test its characteristics experimentally. The hysteresis effect, that is caused by the stress-strain characteristics of the material, was experimentally clarified. An index for showing the degree of this hysteresis was proposed. As for the time response, a time lag of 0. 2 [ms] was observed. As for the creep effect, resistance of the rubber remained constant for a long time under constant loading.

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A step response relating displacement to light intensity in a bimorph-type optical actuator consisting of two sheets of PLZT elements is analyzed theoretically, and the experimental equations on the principal parameters included in the theoretical equation of the step response are derived from the fundamental experiment on the PLZT elements with various sizes. Comparing the analytical result with the experimental result of the step response of an optical actuator manufactured as a trial, the results show linear and first-order lag factor characteristics and agree well with each other with regard to the final value of the displacement. The time constant in the analysis shows a value 0.44 times as great as that in the experiment. The cause for this difference is discussed in detail. If this cause is taken into consideration, the dynamic characteristics of a bimorph-type optical actuator may be estimated exactly by the analytical result shown in this paper.

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This paper daels with the maximum output power of a trial piezoelectric pump as a first step in developing small-sized hydraulic actuators for robots and mechatronic devices, where the main parts of the pump are inlet . outlet valves, connective pipes between the valves and the pressure chambers, and a diaphragm driven by a multilayered piezoelectric element of 22 mm diameter, 55.5 mm length and 170 g mass. The experimental results show that the pumping power takes a maximum value when the driving frequency coincides with the resonant frequency of the working liquid in the pipes, and that the maximum pumping power is 34 W for the pipes with 300 Hz resonant frequency. On the other hand, theoretical consideration of optimal driving of the piezoelectric element indicates that the above pumping power is increased by 70% using appropriate resonant pipes and a pumping chamber of piston-cylinder type instead of the diaphragm.

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In order to manually operate a robot under an extreme environment or make a remote medical diagnosis from a distant place freely, tele-existence technology of a high order is desired. In particular, the visual system plays an important role. However, in head-mounted displays (HMD) up to the present, ones that are superior in quality of display have only a narrow field of view, while ones having a wide field of view are inferior in quality of display, and no sufficient HMD satisfying both requirements has yet been developed. In this study, we intended to extend the field of view of HMD without sacrificing good quality of display by setting a pair of monocular fields of view on both sides of a central binocular field of view in consideration of the information acceptance properties of the human visual system. As a result of observation by an experimental HMD of our own making, sufficient HMD properties were confirmed. This experimental HMD has a wide horizontal field of view of about 80°in contrast to about 30°for the existing HMD, as well as sufficient display quality, showing it to be a superior tele-existence visual system with good sense of actual attendance.

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In measurement using a laser, it is often necessary to determine the location and broadness of the light intensity distribution curve of the laser beam. A new method was proposed for determining the two-dimensional (2-D) location and broadness of the intensity distribution curve of a laser beam using the location of the main axis and standard deviation of the 2-D Gaussian function which was determined from measured intensities by the least squares method. The equations were derived for rapidly calculating the 2-D Gaussian function, together with the location of its main axis and standard deviation. As an example of the use of this method, the intensity distribution of a He-Ne laser beam was obtained with a CCD camera, and the 2-D Gaussian function, together with the location of its main axis and standard deviation, was determined from these equations.

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In response to the recent trend of increasing speed on railways, it is necessary to maintain good riding conditions and reduce lateral force. In this paper, a pendulum vehicle with guided steering device by Z-link, which transmit the relative yaw angle between the car body and bogie frame to the wheel set to improve steering ability, and with a car body tilt control system is modelled to provide nonlinearity at various springs and dampers. The effect of the device and system is studied by simulation of curving performance. The results show that good riding conditions are maintained and lateral force is reduced. In addition, the influence of lever length of the Z-link steering and longitudinal stiffness of the axle box, and the leverage ratio for well balanced reduction of lateral force are discussed.

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Digital control and robust stability are presented for stabilizing time-delay systems with saturated-type nonlinearity, using multirate sampled data analysis. First, a new digital controller for stabilization is proposed, which is more effective than the usual Smith method, and its characteristics is clarified. Second, the error function due to dead time alteration is derived, by which the robust stability condition is obtained in the discrete time-delay system. Finally, by applying the digital compensator based on this method to the electropneumatic valve positioner, it is confirmed through simulation studies that both the controller and its robust stability analysis are valid.

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This paper presents a model following control of robot manipulators with nonlinear joint flexibility, using a simple design procedure based on the Lie derivative. The nonlinear robot system will be linearized by means of nonlinear-state feedback and nonlinear-state transformation. The simulation results for 2-link manipulators show the validity of the design procedure and that the control errors can be suppressed to a smaller size than in the usual control method.

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In this paper, the following two control methods are proposed for path tracking control of robot manipulators : (1) digital control method based on the principle of movement of a nonlinear mechanical system : (2) preview control method utilizing future information of the desired trajectory to improve the tracking control performance of method (1). The features are (a) systematically derived digital control law, (b) disturbance terms that may be unknown if they are functions of position and velocity. Finally, the effectiveness of the proposed control methods is shown by simulation studies and experimental studies.

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In designing planar mechanisms, individual links constructing the mechanisms must be arranged separately on parallel planes to avoid mutual interference during a cycle of motion and the mechanisms have to be constructed in the smallest space possible. In this paper, as for planar eight-bar crank mechanisms with only revolute pairs, the layer arrangement with the minimum number of layers is determined taking the conditions of construction of mechanisms and the full rotation of pairs into consideration. Furthermore, the above-mentioned numbers are applied to classify the types of the eight-bar crank mechanisms which reveal the locations of moving planes of the links and pairs.

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This paper presents the trial formation of a variable-stiffness spring and its application to displacement control problems. The variable-stiffness spring is a coiled spring which can vary its spring constant on account of a mechanical system composed of a stepping motor, gears, trapezoidal screws, joints, and a circular plate. It is used as an actuating device of an intelligent adaptive beam. The results of the deflection control experiment of this beam subjected to static and dynamic loads are presented.

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A simulation model has been developed to estimate belt load by replacing the layout (L/O) around the engine synchronous drive belt and cam pulley with a simple vibration model based on the spring-mass system. Verification of the belt load generation mechanism was made between calculated and measured belt load values based upon DOHC engines with different number of cylinders. Another verification was made for the belt load generation mechanism in the SOHC engine with different initial belt tension value. This report describes the specifications of our simulation model and the results of verification.

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The design formulae for calculating the number of contact teeth in gear-type shaft coupling which has random pitch errors and their load capacity are proposed. Before derivation of the formulae, a theoretical analysis is conducted and the results are confirmed by numerical simulation using Gaussian random numbers which correspond to the pitch errors or the allowable stress of the material of gear-type shaft coupling. The formulae are obtained by means of regression analysis of the theoretical results in various cases.

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When hypoid gears are used in automobile rear axles, the gear axes are relatively displaced. The relative displacement of gear axes causes gear noise. In order to reduce gear noise, it is necessary to modify the tooth surfaces of the gears. In this paper, a method for cutting hypoid gears with modified tooth surfaces is proposed. In this method, the nongenerated ring gear is cut by a cutter in which each cutting edge is modified from the usual straight line to a circular arc with a large radius of curvature and the pinion is generated by a cutter with straight cutting edges as usual. Although an irregular tooth surface which does not mesh with the mating surface is apt to appear on the pinion tooth flank during manufacturing, with this method, the surface does not appear. The main procedure of this method is the determination of the machine settings for the Gleason hypoid generator. In order to confirm the validity of the method, a pair of hypoid gears was designed and manufactured using this method. As a result, the tooth bearing was acceptable and the appearance of the irregular tooth surface could be avoided.

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The measurement of transmission error of power transmission gears is a useful tool by developing quieter gear units. Precise measurement using the conventional system with rotary encoders is, however, considerably difficult, because of elastic deformation of the measuring apparatus and connecting members between gears and encoders. In order to solve this problem a new measuring system using laser optical units, which measure the peripheral speed flutters of the rotation of the pinion and gear or their chucking bodies, has been developed. Transmission errors are calculated by integrating the difference between the speed flutter of the pinion and that of the gear. During the basic performance test of this measuring setup, in which both optical units were installed on the peripheral surface of a single rotor, an excellent noise level of 0. 002% speed flutter was confirmed. In the application test for hypoid gears, the measured values of transmission error in the tooth mesh and its higher harmonic frequency components correspond sufficiently to the values obtained using the traditional vibration tester and to those using the single flank tester of rotary encoder type.

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Temperature dependence of the strength of commercial cutting wheels was examined using three- point bending tests. Fracture occurred inside the bond without exception. Bending strength depended not on the bond of the grain on the abrasive wheel but on the fraction of the bond. Increase in the grade abrasive and bonding grade of the wheel results in the increase in the volume fraction of the bond. Thus the bending strength of the wheel becomes high. The bending strength first decreases with temperature up to 100°C and then increases up to 160°C. Above 180°C, the strength decreases sharply. The change in strength with temperature might be attributed to the bridging phenomena and glass transformation of the bond.

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This paper examines a design method for kinematic accuracy of machine tools under the constraints on the required machining accuracy of the products to be machined. A mathematical model is proposed to represent relative motion between the tools and the workpieces which includes the kinematic errors of machine tools. The relation between the geometric errors of the product surfaces and the kinematic errors is analyzed and formulated for typical end milling processes. A design method is proposed to determine suitable values of kinematic accuracy by applying a nonlinear optimization method under the constraints on the geometric accuracy of the product surfaces to be machined.

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The basic construction of a SF₆ circuit breaker depends on the linkage system which should be made of strong and lightweight materials. For proper design, it is important to first understand the load characteristics, because an operating force with a steep wave front applies a complicated impact load on the linkage system due to factors such as elasticity, viscosity and play of joints. This paper presents practical methods to understand the load characteristics through the comparison of the simple models of spring-mass systems with the test results of three-phase gang operated breakers. A valuable design guide and cautions are presented. For example, excessive load is applied on the operating rod with the greatest elasticity of the three phase linkage systems, and equal elasticity of each phase linkage decreases the load.

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In layout design problems including blank nesting, the positions and directions of layout elements must be determined so as to minimize the total space. It is difficult and computationally time-consuming to find the optimal solution for such layout problems, because they include numerous underlying combinational conditions. In this paper, we develop an approach for optimal nesting by combining a genetic algorithm and a local minimization algorithm. In the approach, the genetic algorithm is used for handling combinations which are represented in the string, and the local minimization algorithm is used for determining the embodiment layout under fixed combinations so as to minimize the scrap space corresponding to the fitness value in the genetic algorithm. We also present an example for showing the effective nesting result produced by this approach.

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The job-shop scheduling problem is a well-known planning problem. The solution should incorporate production control. This paper aims at developing a new scheduling system based on the decentralized management approach to describing a mathematical model of the autonomic machines. Here, in order to develop a more generalized theory for the control of autonomic machines, the vibrating potential method (VPM) is introduced. The VPM is characterized by placement of each unit's potential function on its own harmonic wave as an axis. Each unit receives potential energy from the vibrating potential field (VPF) by convolution and determines its own strategy of motion independently. This paper proposes a new control method to be used in the field and discusses its application to the job-shop scheduling problem.

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