This paper describes synchronization of two self-excited vibratory machines with local velocity feedback. In vibration transportation by decentralized vibratory machines, the resonance frequency of a vibratory machine varies with the movement of a work. Self-excited vibration by positive velocity feedback follows the resonance frequency change automatically in individual machine. The frequency difference of two vibratory machines stops transportation and makes large noise. The synchronization control has the feedback loop of the average of velocities in two vibratory machines. For small gain in synchronization control, local control has positive velocity feedback, and self-excited vibration is generated in resonance frequency. For large gain, local control has negative velocity feedback to suppress forced vibration by synchronization control, and then two vibratory machines vibrate in the same frequency. Synchronization of two vibratory machines realizes quiet and smooth transportation.

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There are a lot of nonlinear phenomena in the world, and it is confirmed that the chaos is contained in the nonlinear vibration. In this study, the vibration model, which mechanical spring is set on pepnendicular to the moving direction, has been proposed. This model is described by mass, damping constant, nonlinear restoring force. The goveirning equation of this model is nonlinear, like Duffing equation. Numerical calculations were performed and the effect of k_m, which shows the strength of nonlinear elastic force, on the motion of system has been investigated by the bifurcation diagram, time series, Poincare map and power spectra.

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In this paper, bifurcation phenomenon of rocking of a rectangular parallelepiped block is dealt with. Since the locking is typical nonlinear vibration, the equations of motion are solved numerically and bifurcation diagrams, fixed points and invariant curves, regions of attraction and bifurcation-set are obtained. It is seen that the period-doubling bifurcation, the transcritical bifurcation and the saddle-node bifurcation exist.

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This paper describes an approximate structural optimization method by using the Kriging method and an optimization method using gradient components of an objective function. The Kriging method requires an assumption on semivariogram model, an approximated surface can be generated without an assumption on an order of base function for approximation. In this paper, Gauss model is assumed as a semivariogram. The proposed method consists of two main processes. 0ne is a space approximation process by the Kriging method, and another is an optimization process. In the proposed method, a gradient component on an approximated surface is obtained analytically by using an assumed semivariogram. Some numerical examples are illustrated to evaluate an applicability of the Kriging method to a structural optimization. And to illustrate effectiveness of the proposed method, two structural optimization problems are solved by using the proposed method. Numerical results show effectiveness and validity of the proposed method.

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A basic research is being carried out on transport of particles and particle size classification in electrostatic traveling field. A particle conveyor consisting of parallel electrodes was constructed and four-phase traveling electrostatic wave was applied to the electrodes to transport particles on the conveyer. The following were clarified by the experiment : (1) Particles were transported almost linearly with time. A transport rate was also linear with applied voltage but a threshold existed due to adhesion force. (2) The direction of particle transport did not always coincide with that of the traveling wave but partially changed depending on the frequency of the traveling wave, the particle diameter, and the electric field. Particles were vibrated but not transported under high frequency field. (3) Particles were efficiently transported under conditions of low frequency, high voltage, and the application of rectangular wave. (4) Particles were classified with size under the voltage application of appropriate frequency.

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In the present paper, the analytical treatments of dynamic behavior of beams on a viscoelastic foundation subjected to axial force and moving loads under spring and damping are shown by using of transfer matrix method to determine the natural frequencies and mode shapes of the beams. Dynamic responses of a single-span, simply supported uniform beam subjected to axial force and a moving load with constant velocity were studied. The results of the present paper were compared with the exact solution. It was found that good agreement was achieved. The accuracy, dynamic responses of multispan beams are illustrated through several numerical results by using of the transfer matrix method.

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Elastic impacts of two spheres are treated by Hertz's theory of impact. However, plastic deformation arises due to impact in general. The severity of impact is generally characterized by Coefficient of Restitution. Present paper intends to investigate the effects of plastic deformation on the Coefficient of Restitution in direct central impact of two equivalent spheres. At first, the solutions for the impacts of two equivalent spheres obtained from Finite Element analyses and those from Hertz's theory of impact were compared. Then the experiments of direct central impact of two spheres were conducted for bearing steel balls (JIS SUJ 2). The steel balls were impacted by pendulum motions. Tensile tests were conducted for bar type test pieces to obtain the mechanical properties of SUJ 2. The test pieces and the spheres were annealed under same condition before the experiments. Coefficients of Restitution obtained from the experiments and from Finite Element Method were compared. And the coefficients of restitution and the duration of impact were presented as a function of the relative impact velocities.

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Constraints appeared most commonly as actuator bounds on control variables and/or physical limits on state variables, are inherent characteristics in almost all practical control systems. Violations of such constraints drastically degrade system performances and in worst cases lead to instability. In order to escape the performance degradation as much as possible, colorful control approaches for such systems with state and/or control constraints have been well studied in recent years. This paper verifies the control approaches, an off-line reference management technique and a static and a dynamic anti-windup control, for such linear constrained systems. To this goal, we practically identify a mathematical model of a RC helicopter by frequency response method, design a controller by loop shaping design procedure and construct a real closed loop system with the RC helicopter. In practice control, we apply each control approaches to its yawing tracking control problem. At last, we show results gained from the approaches and discuss effectiveness and validity of each approaches.

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Since the circular velocity bias system enables the 3-D measurement for multiple points from a single image, the system is suitable for the measurement of unsteady phenomena such as particle movement in water flow. In this paper practical improvement of velocity bias system using multi spot laser is introduced. Using the multi spot laser, effective calibration method is established and the accurate measurement can be realized by considering the parameter of the each laser spot. The measurement of a moving surface such as a free surface of water is introduced for one of the applications of circular velocity bias system. This measurement can be realized by utilizing the peculiarity of our system and multi spot laser. Experiments show the feasibility of our method.

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This paper investigates the use of four-wheel-steering system for the control of vehicle, in the context of automatic lane-keeping. Four-wheel-steering system provides two independent control inputs which can much enhance handling and stability, thus it is expected that such system can also provide satisfactory lane-keeping performance. Here, lateral deviation of front and rear virtual points are proposed to be state variables in control system design procedure instead of lateral deviation at center of gravity and yaw deviation. As a result, decoupling of lateral and yaw motion control can be realized during lane-keeping maneuver. Finally, simulations in straight and curved lane-keeping are conducted to investigate the validity of the proposed control system.

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The guaranteed cost control problem of the decentralized robust control for large-scale interconnected delay systems with the norm-bounded time-varying parameter uncertainties and a given quadratic cost function is considered. Sufficient conditions for the existence of guaranteed cost controllers are given in terms of linear matrix inequality (LMI). It is shown that the decentralized local state feedback controllers can be obtained by solving the LMI.

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In the present paper, we examine the Model Feedback Control System. Since the Model Feedback Control System is simple, the ModeI Feedback ControI System has been applied to many applications such as the trajectory control of robot manipulator, level control of serially connected tanks and so on. Since the control structure of the ModeI Feedback Control System has constrained, it is likely that the Model Feedback Control System can not represent all of stabilizing controllers for the plant. Nothing has been reported whether or not, the ModeI Feedback Control System can represent all of stabilizing controllers. The purpose of the present paper is to give a solution to the question whether or not, all of stabilizing controllers for the plant are written as the Model Feedback Control structure. Since Model Feedback Control System is applied to many minimum phase systems, in the present paper, we especially clarify the relationship between the ModeI Feedback Control System and the parametrization of all stabilizing controllers for the minimum phase system. First, the relationship between the Model Feedback Control system and the parametrization by Glaria and Goodwin is clarified. Next, for the strictly proper system, the relationship between the Model Feedback Control System and the parametrization by Yamada and Moki is presented. Simple design method of the Model Feedback ControI System to specify control characteristics is shown.

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A large number of tactile ground surface indicators for sight disables are constructed on sidewalks in Japan. These indicators have many protuberances, so sight disables can detect them. However, these protuberances could be an extra barrier for people who do not use those indicators. The purpose of this study is to investigate the effect of tactile ground surface indicators to human gait. Especially toe clearance to avoid tripping. Subjects were 9 young male with normal vision. Those subjects were asked to walk through the path with three different surfaces ; a warning indicators constructed path, a leading indicators constructed path, and a no indicators constructed path. Measurements were carried out using a VICON 3D tracking system and 8 force plates. When they walked through the paths with either indicators, minimum toe clearances was significantly increased for most of the subjects. We also found hip moments are the most common cause to increase minimum toe clearances.

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This paper describes the method used to design the basic control algorithm of a lane-keeping support system that is intended to assist the driver's steering action. Lane-keeping control has been designed with steering torque as the control input without providing a minor loop for the steering angle. This approach was taken in order to achieve an optimum balance of lane-keeping control, ease of steering intervention by the driver. The servo control system was designed on the basis of H₂ control theory. Robustness against disturbances, vehicle nonlinearity and parameter variation was confirmed by μ-analysis.

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We propose the Pl controller combined with neural network to position control of USM. The PI controller can control even if the control objects is strange. However, in case of the control object is nonlinear or time varying system, Pl controller cannot carry out precise control. This proposed method, the Pl controller is used as main, and NN rectifies the portion which cannot be compensated by Pl controller. Weights of NN are adjusted by back propagation method so that control error may be minimized. And drive frequency is selected by two values to realize high-speed position control. The effectiveness of proposed design method is confirmed by experiments using the existent USM.

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Semisolid forming for Al-Al₃Ni functionally graded material (FGM) is investigated to detect the optimum operating temperature which can optimize the microstructure of the material. Because it is difficult to identify the optimum operating temperature of Al-Al₃Ni FGM billet when it is set in a container. One of the idea is an application of a wavelet analysis to detect the transition temperature of Al-Al₃Ni FGM billet from solid to semi-solid state. Haar's wavelet function is applied for its simplicity compared with Daubechies' wavelet function. An online wavelet analysis system using Haar's wavelet function is developed and a semisolid forming system to produce an FGM cup is constructed. The system successfully detects a discontinuity of deformation of Al-Al₃Ni FGM with temperature increase under a constant applied load. The idea was confirmed to be suitable from the micro structural observation of formed cup, because the formed cup under the optimum condition was found to have a refined microstructure of Al-Al₃Ni system, which is expected to improve the mechanical properties.

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In this paper, we propose a control system design method in consideration of actuator saturation. By using the hyperbolic tangential function as a saturation description, we introduce both the time derivative of control input and the anti-windup control structure with feedback of the error between the input and the output of the saturation function. Furthermore, we formulate a linear parameter-varying system to design the gain-scheduled controller. The effectiveness of our proposed method is verified by carrying out experiments of positioning control for a cart and inverted pendulum system.

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System identification of a motorcycle by Computer-Aided Dynamics Analysis is introduced to design a control system for the attitude stabilization. The identified model can be reduced to the coupled mode system between the roll mode and the front-steering mode. We design the gainscheduled front-steering control system using the roll angle as the feedback signal, which is according to the varying parameter of motorcycle velocity. It is verified from simulation results that the motorcycle attitude against disturbances is stabilized by the gain-scheduled controller at the wide range velocity.

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In the first report, we described the state estimation observer in the frequency domain. In this paper, a disturbance estimation observer is newly proposed also based on the frequency domain and the structure condition for its design is derived through error analysis. This disturbance observer can be directly and easily constructed from the plant transfer function by applying a diophantine equation with estimation error dynamics depending on input/output disturbance frequency characteristics. The proposed method is applicable to estimate not only input disturbances but also output disturbances. Further, it can also deal with a sinusoidal disturbance. A design example is presented in which the new approach has a good estimation performance for various types of disturbances.

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In this paper, we present a new servo system to solve the visual servo control problem for 3DOF manipulator using fixed stereovision configuration. In order to accurately and quickly move the end-effector to the static/moving target on 3D-space, we propose a new position-based visual servoing method. 0ne method is a servo system that uses the position of the endeffector by position sensor, it is effective for the high-speed tracking. The other method is a servo system that uses the position of the endeffector by vision sensor, it is effective for the accurate positioning. And, we apply the proposed servo system to the experimental system that consists of an off-the-shelf CCD camera, which has high resolution. As a result, experiments have shown that it decreases steady-state deviation for a static and moving target on 3D-space without deteriorating the tracking performance. And they also have shown that it is independent of errors in lens radial distortion and the declination between camera coordinate and manipulator coordinate.

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In this paper, a problem of trajectory planning for a mobile manipulator with stability considerations is presented. We derive the dynamics of the mobile manipulator considering it as the combined system of the manipulator and the mobile platform. As a measure for the system stability, a ZMP criterion is used. The planning problem is formulated as an optimal control problem with some constraints. To solve the problem, we use a hierarchical gradient method which synthesizes the gradient function in a hierarchical manner based on the order of priority. The simulation results of the 2-link planar nonholonomic mobile manipulator are given to show the effectiveness of the proposed algorithm.

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The dynamic motion simulator for mechanisms with a tree structure has been developed. Elements of an inertia matrix giving linear equations of joint accelerations is composed of bilinear forms of joint screws and the summation of the inertia binors of links. lt is clarified that the summation of the inertia binors of the ijth element can be determined by the links located in the upper part of both the ith and ith joints. The recursive computation algorithm for determining the inertia matrix is derived by utilizing the inverse of the incident matrix of the mechanism.

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Magnetorheoloeical (MR) fluids are materials that change their rheological behavior by an applied magnetic field. They have been attracted as functional fluids that can improve properties of mechanical systems. We have developed an actuator using MR fluid. In the previous paper, a design method of MR-fluid actuator was proposed by using magnetic circuit theory. The basic experiments were carried out and the static properties that agreed well with the design were obtained. However, the transient response that wasn't considered in the design phase was not so fast. In this paper, we investigate the dynamics of the MR-fluid actuator and aim to improve the response. The transient magnetic analysis is examined in consideration of the eddy current. Two approaches are proposed to improve the response. Finally, we realize a much faster MR-fluid actuator.

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Because of low cost and accurate transfer characteristic, timing belt drives are widely used in servo systems such as industrial robots and office automation equipments. ln the servo systems, high performances are required for high productivity and quality of goods. High stiffness of drive system is expected in timing belt drives. We propose a method to estimate the torsional stiffness of the belt drive by using tensile experimental results. First, the torsoinal stiffness is analytically derived from shaft load and tensile stiffness when the driving and driven pulleys have the same radii. Next, in the case of different radii (reduction system), the relation between the shaft load and the torsional stiffness is analyzed by the same approach. Finally, tensile and torsional experiments are carried out. lt is confirmed that the analized results are in good agreement with the experimental results.

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In our previous work, we developed a compact 6-DOF haptic interface. The haptic interface contains a modified DELTA parallel-link positioning mechanism. A stiffness of the modified DELTA mechanism is affected by elastic deformations of both parts and bearings. Therefore, to design such a parallel mechanism, we should analyze structural stiffness of a parallel mechanism, including elastic deformation of both parts and bearings. Then, we have proposed an analysis method of structural stiffness for a parallel mechanism. ln this paper, we design a modified DELTA mechanism with a suitable stiffness, using our stiffness analysis method.

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Orbicularis oris superior (OOS), orbicularis oris inferior (OOI), levator anguli oris (LAO), depressor anguli oris (DAO), and mentalis (Ment) are considered as typical perioral muscles that contribute to the force and pressure occurence in and around lip aperture. This study presents the experimental and analytical results that show correlationships between eledrical muscle activities and mechanical parameters on bilabial closing force, puckering force, POM (perioral muscle) value and so forth. Besides, zero-lag correlation coefficients between rectified and smoothed SEMG signals of LAO and DAO was constantly higher than other muscle combinations including OOS-OOI combination considered to be most closely related with lip movement. Among lip tasks, prominently high correlation between LAO and DAO was shown when subjects tried to close their lip bilabially at principally distal part. Consequently authors succeeded to prove the great importance of the coordination between LAO and DAO for producing bilabial consonants, drinking and eating, pooling saliva in oral cavity, and others, while the applicability of POM meter to myofunctional therapy is obscured.

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A low noise gear without lubrication is presented, which is made of COPNA material involving Graphite. The noise between steel gear and the present gear is investigated experimentally. The experiment is also performed to the gear mechanism using ordinary plastic gears. It is clarified that the noise from the gears is small as compared with ordinary plastic gears without lubrication. Especially, the noise of the present gear is significantly small when the gear is rotated under a load. The mechanism of noise suppression in our gear is investigated.

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Gear coupling is composed of one hub and one sleeve. The hub of gear coupling is external gear that has barrel shape and the sleeve is internal gear. External gear of barrel shape is called as pinion in this paper. In the research process of tooth contact of gear coupling, authors measured the tooth profile of pinion and found that tooth profile possibly has deviation of helix angle and pressure angle. We guess that this might be theoretical deviation caused on hob cutting, because pinion in gear coupling has barrel shape. This paper analyses theoretically the profile of gear coupling-pinion, then fits the 3-D measuring data to the theoretical profile. The results show that deviations of helix angle and pressure angle of the pinion almost correspond to the theoretical deviation of hob cutting.

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There are great advantages in dry hobbing not only for friendliness on the environment, but also for increasing processing speed, productivity and for decreasing manufacturing cost. Dry hobbing, however, often causes failures of cutting edge of hob or problems about the surface quality of tooth flank of manufactured gear, which have not been of problem in case of hobbing with cutting oil. Pinching and crushing of generated chips between cutting edge of hob and tooth flank is considered to be a major cause for those problems. In this report, a simulation method of trace of each cutting edge of hob relative to gear blank is developed. This simulation makes it possible to calculate the clearance between cutting edge of hob and tooth flank of gear blank. The thickness and form of generated chip and its movement on rake surface of hob tooth can be clarified. This achieves easy understanding of those values during bobbing process. Probability of pinching of chips between cutting edges of hob and tooth flank can be evaluated by position and width of clearance, chip thickness and direction of chip movement, which contributes to successful dry hobbing.

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The simulation program developed in the former report that calculates the clearance between cutting edge of hob and tooth flank of gear blank is applied to some practical industrial problems of dry hob cutting, i.e. chipping failure of cutting edge of carbide hob and bad coarse surface finish of hobbed tooth flank of product gears. The output of the simulation explains the mechanism of such actual failures in detail. The "Distance of Single Edge Cutting" of a hob tooth is proposed to be an index of pinching and crushing of chips intruded into the clearance between hob cutting edge and tooth flank of gear blank. Influencing factors on it is investigated and the bases for finding countermeasures are shown. This method has been applied to some practical cases of problem in mass-production of automotive gears, and good result was confirmed.

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Because the crosshead-pin bearing for large size two-stroke diesel engines oscillates within a small angle at a low speed and is always subject to a high downward load, the hydrodynamic oil film is very thin. The recent tendency to raise the engine power using compact engines continues to increase the lubrication severity of the bearing. It is thus very important to improve the load carrying capacity of the bearing. In the present study, calculations were carried out to clarify the lubrication characteristics for the crosshead-pin bearing with a very low clearance ratio and wedge geometry incorporated oil-grooves. Reducing the bearing clearance ratio is advantageous for enhancing squeeze action on the entirety of the bearing pads, thereby decreasing the oil film pressure. However, this also has a negative aspect of reducing wedge action, causing the oil film thickness to decrease. Even when the clearance ratio becomes very low, incorporating a wedge geometry on both sides of the oil-grooves is an effective means to improve wedge action, and thereby to increase the oil film thickness without a significant raise in the oil film pressure.

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In the 1st report, the Elrod's cavitation algorithm was modified and applied to the mass conserving elastohydrodynamic lubrication, EHL, theory with a simple model of oil flow in an oil passage. In the 2nd report, the feature of the mass conserving EHL with oil passage was shown in comparison with the conventional EHL. In this report, the oil flow rate to a con-rod big-end bearing of an experimental engine was measured using a hot film anemometer under many operating conditions. The experimental results were compared with the theoretical calculations using the mass conserving EHL with oil passage. The theoretical cycle averaged oil flow rates to con-rod big-end bearing qualitatively agreed with the experimental ones.

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A gear test and a two-cylinder test were carried out under non-lubricating condition in high vacuum to investigate the friction and wear behaviors of electroless Ni based alloy plated gears in vacuum. The gear test results were compared with the two-cylinder test results. Three kinds of electroless Ni based alloy platings and two kinds of composite platings with dispersed particles were employed here. In case of the Ni-P alloy plated gear with dispersed PTEE particles, the wear was almost uniform along the tooth profile and the fluctuation of the dynamic load was small. In cases of the Ni-B alloy plating, the Ni-P-B alloy plating and the Ni-P alloy plating with dispersed BN particles, the wear of the gear pairs was large, while the wear of the cylinders was rather small. Though the wear in the two-cylinder test was much smaller than that in the gear test, the average friction coefficients in both the two tests were almost the same with each other.

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Automatic prediction of contact between a grinding wheel and a workpiece has been required from production engineers. The appearance of a trailing flow of grinding fluid, which passes through the clearance between the grinding wheel and the workpiece, will change from transparent to white as the clearance decreases. Since the reflected intensity of diffused laser beam from the trailing flow will depend on the degree of transparency of grinding fluid, the intensity change can be used for the estimation of the clearance and the prediction of contact. Firstly, the effects of grinding wheel peripheral speed, grain volume percentage, grain size and grinding fluid flow rate on the intensity of the defused laser beam are investigated experimentally. As a results, higher wheel speed, lower grain volume percentage, larger grain size and higher flow rate causes higher intensity. Secondly, the estimation of the clearance using the diffused laser detection and the prediction of contact between the grinding wheel and the work piece are demonstrated. An automatic wheel-approach system using the prediction system has been satisfactory developed.

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An attempt to develop a surface texturing technique that allows the production of a fine and uniform textured ground surface was carried out by grinding with ultrasonic longitudinal vibration. In addition, on-machine truing of a newly developed thick-electroplated tool was conducted in order to increase the tool life by diminishing the tool run-out. Profile grinding with the vibration was carried out on a work surface inclined at 45 degrees using a spherical electroplated tool. The feed was adjusted such that the feed rate per single grit was equal to that of the wavelength of the longitudinal vibration. The phase control of the longitudinal vibration was effected by adjusting the tool-path length to generate systematic microindentation patterns. It was verified by grinding tests that a fine and systematic indentation pattern similar to that of sand blasting and etching patterns could be derived by profile grinding. In addition, the tool life of the thick-electroplated tool was increased to be over 10 times longer than that of the conventional electroplated tool by diminishing the tool run-out.

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Shaving is a type of precision shearing method to eliminate fractured surfaces. Its mechanism is known to consist of shearing and cutting, but the conditions for why shaving occurs are still unclear. In this study, we investigated the conditions in which shaving occurs for three cases ; only cutting, only shearing, and in the case of cutting followed by shearing. We also studied the conditions for the shaving mechanism to change when cutting and shearing are mixed. First we compared the cutting force and shearing force, and established the hypothesis of mechanism that lead to smaller force necessary for continuing the work has priority. We also compared the cutting force through experiments, and the shearing force by Maeda's thin layer shearing theory, and studied the hypothesis from the magnitude relation of the two. To confirm the legitimacy of the hypothesis, we also studied the working mechanism by observing the direction of strain hardening around the shaved surface and material deformation. The conditions for which shaving occurs by this working mechanism predicted from the machining force agrreed relatively well with the observation results of atrain hardening and material deformation.

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Recently, some kinds of laser machines have often been used for a special machining. Generally, it has been thought that static stiffness is unnecessary for these machines, because laser machining never generate relative machining force between a laser torch and a work, and the laser elements are very light. Therefore, dynamic stiffness in these machines also became low, and waiting time after the movement of the table is long. Hence, some countermeasures of the structural vibration are necessary for improving availability of the laser machine. In this paper, a vibration countermeasure has been proposed. At first, vibration properties of conventional laser machine was investigated using FEM simulation. Next, damping ratio of the structure was improved by the powder composite damper. It is concluded from the results that ; (1) The number of natural frequency on low frequency territory decreased and the compliance became small. (2) The logarithmic decrement of the structure became big.

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Some kinds of singular dynamic phenomena were observed in a pin-to-plate gas discharge system. (1) One was vibration of the pin electrode perpendicular to the plate electrode observed at the transition from the dark discharge and the positive corona discharge due to the streamer corona when the axial stiffness of a support of the pin electrode was low. Similar vibration was observed in the negative corona discharge due to Trichel pulse and instability of the negative corona. Both vibrations were the forced vibration due to pulsative or fluctuating electrostatic force caused by ionic wind at corona discharging. (2) Another axial vibration was observed at spark discharge for the softly supported pin electrode. The applied voltage was transiently decreased and then relaxed after the occurrence of the spark discharge and alternative force was induced due to alternative ionic wind. Thus a large forced vibration coupled with the intermittent spark discharge took place. (3) Lateral whirling of the pin electrode was observed at corona discharging when the pin electrode was extremely fine. Whirling frequency was increased with the increase of the applied voltage. Axial repulsive force due to the ionic wind was the cause of the whirling.

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Demands of medical implants such as artificial hones increase as an aged society is coming. A medical implant can be substituted for original tissue only when it satisfies both mechanical properties and biocompatibility. Since such material is not found in nature, hybrid materials are promising and have been developed. In the previous paper, coatings of hydroxyapatite (HA) were deposited on titanium substrate by graded plasma spraying, but the properties of obtained coatings were inferior to those of bone. In this paper, two successive processes were conducted as a grounding of spraying. First stage is a formation of titanium compound which is processed chemically to titanium by NaOH and have high adhesive strength to both titanium and HA. Second stage is HA coatings self-deposited by dipping titanium in Ringer's solution. On these films, 50 μm thickness coating of HA was carried out by plasma spraying in vacuum chamber. It was clarified through the observation of self-deposited surface with SEM and AFM that increase of self-deposit time resulted in improvement of adhesive strength. Self-deposited surface becomes rough in microscopic order but keeps smoothness in mesoscopic, when self-deposited particles of HA grow and cover over the substrate surface. Such surface is easy to bond the sprayed particles by anchor effect as well as chemical affinity and results in increase in adhesive strength.

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