This paper presents the geometrical data for the human femoral shaft. Geometrical properties of the cross section from 13 sites along the bone length (from 20-80% in 5% increments) on each of 31 femoral shafts were calculated by using a digitizing unit and on-line microcomputer. More than 400 cross sections were analyzed in terms of L (circumference), A (gross cortical area), IX (area moment of inertia about the medio-lateral axis), IY (area moment of inertia about the antero-posterior axis), I1 (major principal moment of inertia), I2 (minor principal moment of inertia), IP (polar moment of inertia), PA (orientation of the major principal axis), and SI (section index). SI is a newly defined index: [numerical formula], which represents the deviation of mass distribution of cortical bone in the cross section or the flatness. The results indicate some general tendencies of the change in geometrical properties as a function of the position along the shaft, although there can be found considerable variability in quantity. (1) IY tapers distally in the middle third of the shaft, while IX remains constant along the length of the shaft. Different patterns of the change in the area moments of inertia about the antero-posterior and medio-lateral axes as a function of the section level are expected to correspond to the "structure of uniform strength", if one accepts Pauwels' simplified equilibrium model of lower limb bones in the frontal and sagittal planes; change of IY and IX is similar to that of the bending moments in the two planes. As a result, however, the marginal bending stress inferred in the frontal plane by Pauwels turns out to be incorrect because of the "structure of uniform strength". (2) There exists torsion of the shaft in most of the femurs examined in this study. SI indicates strong flatness at the subtrochanteric region and distal end of the shaft. The variance of PA becomes mimimal at the same regions. These findings suggest local morphological directivities which may involve mechanical significances related to torsion of the femoral neck and rotation of the knee joint. (3) Sex and agerelated differences of the properties normalized by the whole length of the femur were also discussed.

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Normally, arthrodesis is indicated if only an ankle joint is destroyed. However if there are pathological changes in the neighboring joints, it is desirable to preserve joint functions and an artificial ankle joint replacement is indicated in many cases. We made models of the lateral views of ankle joints and performed a comparative investigation of (1) deformations and (2) major and minor principal stresses by means of the finite element method by inferring (1) physiological conditions, (2) conditions immediately after replacement with an artificial ceramic joint, which we developed, without cement, (3) conditions of fusion between the ceramic and the bone a few months after the replacement, and positions of a lower leg (4) standing on one leg medially, (5) inclined posteriorly and (6) inclined anteriorly. The NASTRAN program was used in the analysis and membrane and rod elements were used for element divisions. A tibial component of an artificial joint was loaded mainly on the anterior cortical bone of the tibia and on the posterior cancellous and cortical bone. A component of a talus having a stem in the center replaced a joint surface. The physiological stress distribution was similar to the travecular course. Immediately after replacement with an artificial joint, there was a large amount of stress in the ceramic, but compressive stress was found between the ceramic and the bone. After fusion between the artificial joint and the bone, stress distributions changed to approximately the same conditions as the physiological conditions. These results were investigated comparatively with clinical results.

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Kinematic and kinetic measurement have been performed in rehabilitation and orthopaedic field. However, the most important feasibility of engineering in those fields may be to provid any method by which invisible physical conditions related with disabilities or diseases can be revealed. From the clinical point of view, the conditions can be magnitude of forces exerted on the joints and the muscles, stress value of bones and so on. A mathematical and mechanical model must be constructed to calculatethose values because they cannot be measured directly. And these days, there are several reports about such models. We also made a Neutonian mechanical model in which a human body was modified into five links and each joint moment and joint force was calculated from it. Different from the existing human body, muscle contraction necessary to provide powers was assumed to work so as only to output the moment in the model. A part of the model equations is as follows (see text about definitions); about leg force equilibrium [numerical formula](horizontal)[numerical formula](vertical) and about moment [numerical formula] We analysed level walking('W'), ascending('AS') and descending('DS') stairs (16cm height) and going-up('GU') and -down('GD') platform (42cm height) on a 33-year-old healthy male. Several parameters such as location of segments' mass centers and weights were derived from Dempster's method. Acceleration of the mass centers and angular acceleration of joints were calculated from Selspot data. On the other hand, floor-reaction-force ('FRF') and so-called zero moment point were measured by using handmade instrumented shoes in which commercially available gym shoes with eight miniature load cells in their soles were used. And to get reliable results, each waveform of 10 to 20 movement cycles was normalized in its time scale and averaged. After that procedure, the normalized data were input into the mathematical model. Results about the 'FRF': patterns of 'W' and 'AS' and 'DS' were similar and had two peaks. And maximum peak values were 120, 123 and 142 (% of weight), respectively. Maximum values of 'GU' and 'GD' were 112 and 138 (% of weight) each. About the joint force: patterns of joint forces in each movement were almost identical with each 'FRF' pattern and their maximum values decreased compared with the 'FRF' joint by joint. This may have occured because muscle forces were assumed to play no role on the joint forces. About the moment: different from the force patterns, moment patterns were unique in each movement and each joint. For example, peak value of knee moment in 'W' were +100 and 0(Nm), those in 'AS' and 'DS' were 40 and -10(Nm) and 50 and -25(Nm).

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Valid criteria of gait evaluation have been required in clinical practice. The method for evaluation must be objective and simple although human gait is inherently complex and many parameters are tangled with each other. In order to find a solution to this problem, a new evaluation method has been developed. The gait records of 211 cases of patients with hip diseases have been measured. The measurements of five gait parameters, namely, angular displacement for joint of lower extremities, floor reaction forces, trajectory for point of force application, gait duration time, and step length, are performed using a minicomputer. Gait data are normalized, numerized and summarized in synthetic values by principal component analysis. As a result, two principal components which reveal 'general walking ability' and 'balance between the symmetry and the activity' are obtained. A patient's factor score for these principal components are in good agreement with his or her clinical situation. Gait characteristics caused by the extent of the lesion and the method of treatment procedure could be compared on a scale using factor scores. Gait data are averaged among the patients of similar factor scores and compared with each other. Some characteristics of the gait of patients for each treatment procedure, such as conservative treatment, total hip replacement, and hip fusion, are clarified. Further, the joint moments of stance phase due to the floor reaction force are calculated for some patients. The results give the following information: 1) For the conservative treatment, Walking patterns are affected by the pain, the leg-length discrepancy and the range of the motion of joints. 2) Patients with total hip replacement walk at a slow speed but with good symmetry while the patients with hip fusion walk at a high speed but with prominent unbalance. 3) The moment of the hip joint is large for patients with serious lesions but is reduced by operation.

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The studies of human locomotion have been well documented and analyzed by many investigators. However, most of them deal with the normal and pathological gaits of the adult and there has been very little literature pertaining comprehensive analysis of infant locomotion from a biomechanical aspect. This report concerns with the level walking of the infant of 3 and 4 years of age as compared with that of the juvenile and the adult. The experimental method for simultaneous recording of the kinematic and dynamic data consisted of cinematography and force platform having a three-dimensional force-transducer. Using the data obtained from these methods, the simulation was carried out by a two-dimensional mathematical model. Thus joint moments, joint reactions, muscular forces, transmitted forces at joints and generated power were estimated. It was clarified that while some variables were identical to adult values, the propulsive mechanism as well as the angle, moment and transmitted force at the knee joint and the generated power in the infant was different from those of the adult. The comparison with non-human primate bipedal walking indicates that the locomotion of the infant may be placed between the human type and the non-human primate type, although it is much nearer to the human type.

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Nine men and nine women walked on a level platform at various speeds. The force components of the foot in the vertical, sagittal and transverse directions, vertical displacements of points on the body in the saggital plane, and the angular movements of the lower limb joints in the saggital plane were measured simultaneously. The correlations between the speed and many other measurements were calculated. The variations of the measurements were shown and discussed concerning with the speed.

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The foot is composed of approximately thirty bones and several ligaments, and its size and shape are deformed by the force applied while walking. Deformation is not only an important factor of the fitness of the foot to the shoe, but also the cause of many problems concerning both elements. In this study, we attempted to measure the dynamic change of the foot-size and the force applied while walking. The foot-length and the foot-width were measured by a newly developed light displacement sensor using strain gages. The footheight and the whole motion of the foot were measured by the 16mm cine-film analysis system. The force applied to the heel, the medial fore part and the lateral fore part of the foot were measured independently by a special designed three-parted force plate. Each plate is capable of measuring the three components of the floor reaction force and the center of application. Further, in order to know the pressure distribution of the foot in the shoe, small and thin pressure gages were fixed on the heel and on the side part and the sole part of the big toe and the little toe. Using these measuring instruments and a microcomputer, we composed a total measuring system for shoe-walking. The experimental results from nine subjects show that the average length chage of arch chords is about 10 to 15mm during normal level walking, but that the tarsalia part is little deformed at any stage of walking. According to the characteristic of foot deformation, the foot structure can be simplified by three rigid link models such as the big toe link, other toes link and the heel link which is connected at the ankle joint. The pointed ends of these links correspond to the base of transverse and the longitudinal arch of the foot. From the mathematical link model and the measured data, we calculated the muscle and the ligament forces of arch support. And also, comparing barefoot-walking with shoe-walking, we discussed the reasonable design of the shoe. Consequently, the following results were obtained. (1) The maximum deformation of the foot during the normal level walking is almost 16mm at the medial longitudinal arch. (2) The maximum percent is 15% at the foot-height. (3) The big toe is always flexed while walking, like a grasping motion. (4) The long planter ligament exerts about 30% of arch-support force. (5) The suitable heel-height decreases the muscle load while walking. (6) The height of pressure at the medial fore part of the foot effects comfort in shoe-walking. (7) The rolling motion of the foot decreases with shoe-walking. Especially the application point of the floor reaction force to shoes with flexible soles moves straight and smooth like a wheel.

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The incessant sway of the point of application of the floor reaction even in the most comfortable standing posture is well recognized and has been studied by various methods. Research results are expressed in static terms rather than in dynamics: an average and standard deviation of the sway trajectory for a certain time period are often studied, but as to the dynamics only the frequency analysis is carried out to give some idea of its unsteadiness. In this paper we applied the autoregressive modeling technique to the experimental data obtained by force plate for various conditions; standing normally or on one leg with eyes open/closed. The characteristics estimated by the model were compared with corresponding measured values with respect to the distribution of swaying speed and power spectrum to show the validity of the model. An affirmative result was obtained for each of three standing conditions. The result, also, showed that the variance of the random noise introduced in the modeling process corresponded well to the violence of the sway. The subjects included not only cerebral palsy children but also normal adults standing normally or standing on a single leg with eyes closed to study various standing conditions.

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For the past hundred years cutaneous displays have been suggested for many purposes, including sensory feedback for remote manipulators and prosthetic limbs, sensory aids for the deaf and the blind, control and navigational displays for astronauts and aviators, and so on. Electrocutaneous stimulation using electric pulse trains is one of the most effective cutaneous displays. This paper deals with the human operator's characteristics in compensatory manual tracking system including an electrocutaneous display. Firstly, an electrocutaneous manual compensatory tracking system which consists of a random noise generator, a low-pass filter, a multichannel stimulator, a stimulus pulse energy controller, an isolator and a computer was constructed. Secondly the human operator's characteristics under several parameter situations in a compensatory tracking system, i.e., display transformation method, display gain, and pulse frequency, was estimated from the RMS values of the control errors and the transfer functions of human operators. Thirdly differences between human operator's control performance in various cutaneous and visual tracking displays were discussed. As a result, the optimal condition for the electrocutaneous display in a tracking control system was presented and human operator's control performance in an electrocutaneous manual tracking system was found to be as good as that with vibrotactile display though inferior to that mith visual display.

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In various muscular dystrophies, the surface electromyography and the motor control phenomena were recorded in the compensatory tracking or the voluntary contraction of the Biceps Brachii on each patient. At this tracking experiment, the flexive force was used as the controlled value, and the sine waves of 0.1, 0.4, 0.8 and 1.2Hz were applied for the command value. From these tracking data, the transfer function was computed for the motor control with feedback and feed forward functions on the closed loop. At various kinds of muscle voluntary contractions, which were practiced on the conditions of MVC (Maximal Voluntary Contraction), fast and slow contraction, and motor trackings, myoelectric signals were transformed with Fourier transform into the EMG Power Spectra. The integrated EMG and Mean Power Frequency (MPE) were estimated by the mini-computer. From the results of two experiments, the following items were summarized. 1) In the tracking motion, the control function of the low-pass filter has been shown as the same results in both groups of healthy (HG) and muscular dystrophy patients (MDG). The breaking frequency points and the gain cut-off coefficient of MDG are estimated at lower values than these of HG. 2) The control function of phase adaptation has suddenly decreased from the command value to the slower lag degree of the mean of -101.6, when the command was applied at 0.8 and 1.2Hz. 3) In various voluntary contractions with many levels of force, it is important that a significant linear regressive relation ship has been found between the force level and the integrated EMG (IEMG). The ratio of IEMG/Force in MDG was found to be the low slope, while the ratio in HG was, inversely, the high slope. MDG's muscles were assumed to contract with slow twitch fibers only. 4) In comparision with the EMG Spectra of MPF between HG and MDG, a significant difference was seen in the conditions of optimal tracking activities, fast or slow contraction, and MVC. The high frequency of HG and low frequency of MDG were remarkedly present in MPF in various contractions of their muscles. 5) According to our results, phasic motor units and fast twitch muscle fibers were characterized to be disactivated in the histology of MDG with the progress of the muscular dystrophy.

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Many studies related to human sensation have been made from the point of view of engineering, medical science and psychology. The problem of the quantification of sensation is of great importance and cannot be ignored, although only a few papers on this subject have appeared. This study shows the relationship between the recognition of shape and the electromyogram (EMG) generated in humans on the surface of the extensor carpi radialis muscle. In order to observe the corresponding EMG, the subject was placed inside a shielded room with Ag-AgCl electrodes located at two points on his skin. The two electrodes were spaced 50mm apart, but variation of the separation in the range 5-10mm had no effect on the EMG. Three spectral peaks (100, 160, 250Hz) for the response were obtained for each shape (Sphere, Tetrahedron, Cube). The frequencies corresponding with the peak spectral values in the response are the same, and are independent of the shapes. And from these experimental results, it was confirmed that our theoretical results were valid. Recognition of shape can therefore be quantified as an EMG spectral variation.

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The purpose of this study is to investigate the differences in the lateral dominances among various collegiate athletes by means of a questionnaire survey and motor performance tests. The subjects for this study were members of fifteen sport clubs, 165 male athletes majoring in physical education at the University of Tsukuba, aged 18-23 years. The survey was made of 25 items and 15 items concerning the laterality of the arm and leg. They were tested in ten morphological and motor skill tests; 1) difference of bi-acromion height, 2) weight distribution of left and right feet, 3) grip strength, 4) arm flexion strength, 5) tapping, 6) target accuracy test, 7) leg strength, 8) foot tapping, 9) picking up a pencil and 10) one-foot balance with eyes closed. The results were as follows: (1) The right shoulder of collegiate athletes had a general tendency to slope downward. The overweight tendency of the right foot was found in high jumpers and handball players, but a tendency to overweight of the left foot was observed in rugby and soccer players. (2) As for the grip strength, arm flexion strength, tapping and target accuracy test, throwers and tennis players showed superiority in the right hand, but rugby players did not show significant superiority. (3) In the case of right foot preference, leg strength, foot tapping, picking up a pencil and one foot balance with eyes closed, judoists and throwers showed more superiority than long distance runners. (4) In the case of left foot preference, leg strength of gymnasts showed superiority, but throwers showed superiority in foot tapping. As for picking up a pencil, long distance runners showed superiority in the left foot, but judoists and tennis players showed the reverse tendency.

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It is of great interest to study control laws which produce speech sounds using a large number of muscles to move articulatory organs in precise order. There are many kinds of works on this problem in the linguistic, medical and engineering fields. However, our knowledge is still so small and restricted that we need many years to accumulate data and to organize them in a satisfactory manner. The estimation of the articulatory motion from speech waves is one of the important techniques to be developed in the research of speech production. In this paper, two problems are discussed in the analyses of articulatory movements which use speech production model. First, an adaptation scheme adjusting the articulatory model for each speaker is presented, which is necessary to improve the accuracy of the estimation. The estimated results are compared with the data observed by an X-ray microbeam system, and it is shown that a simple method which uses a linear transform of the base vector to modify the model using a set of speech sounds for 5 vowels, is very effective for the improvement of the estimation accuracy. Second, an extension of the estimation for consonants is presented. For voiceless fricative consonants, a noise source exists in the middle of the vocal tract and the acoustic characteristics of these consonants are mainly determined by the vocal tract configuration between the constriction made by the tongue and the lips. We tried to determine the vocal tract shape of these consonants by the spectral matching between real speech and the synthesized one from the model. Four parameters are used to determine the area function of the vocal tract. Estimation of the area function is tested through the simulation. Studying the distribution of the spectral error for various area functions, it is confirmed that the stable convergence is always assured. And further, the application of the method to real speech waves shows hopeful consequences.

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A measurement system for the three-dimensional position using "SELSPOT" is shown, which has many advantages over the methods with photographs, movies, or other devices, with respect to its on-line measurement, easy operation, fast sampling, fast data processing, and high accuracy. This is important in view of the application that the display of the analyzed data is required soon after the measurement, such as the experiment of sports physiology and rehabilitation. The system is constructed with a measurement subsystem and an analyzing subsystem. The measurement subsystem is constructed with the dual two-dimensional measurement device which is named "SELSPOT", a communication and timing controller, microcomputer for the filing of the data, and external memory devices. The analyzing subsystem is constructed with the random scan type graphic display with the light pen and ten-keyboard for the interactive analysis, the line printer for the numerical data, and the x-y plotter for the hard copy of the screen. This paper proposes a precise method with which the three-dimensional position is calculated from the dual two-dimensional data. This method defines it as the generalized inverse of the characteristic equation on the camera and the detective device, or the middle point of the segment which determines the minimum length of the two principle rays. By the analysis of the detective device and the lens system, the three factors of the following measurement errors and the methods of their compensation is considered: the non-linearity of the position sensitive detector with the distance between the camera and the LED, the interference of the lightning in the experiment room, and the distortion of the lens. On the other hand, this paper also proposes a new method for camera setting which causes the least error in the calculated data. In the results, the worst accuracy is ±0.4% with error compensation, and ±2.0% without the compensation, respectively. In addition, as the software of the analyzing subsystem realizes the interactive processing and the sufficient function, the period for the display and analysis of the three-dimensional movement is shortened.

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An objective estimation of the working ability of the disabled is one of the consecutive studies necessary for their return to social life. These studies are being carried on in the rehabilitation centers in the health care system. As an independent ADL is essential to the recovery of an individual life without help, so an independence in working environment is a requirement for independent social life. The true object of health care is to make the disabled join social activities. To promote the employment of the disabled, it is essential to estimate accurately their individual ability, judge their individual aptitude and prepare a training program aimed at the utmost development of their latent possibilities. Ultimately it is important to find suitable jobs for them. In oder to evaluate the working ability of the disabled, a computerized pegboard was made for the purpose of a synthetic evaluation of their ability of motion, perception and judgement, and a training evaluation program was prepared. It was applied to more than ten cases of cerebral apoplexy and revealed that there is a difference between the cases with each test, and that an improvement of working efficiency is recognized with each test, etc. A comparison between the measured values and the standard time, an estimate of each individual's ultimate working efficiency to be achieved and each person's adaptability to industrial environment were also examined. The evaluation method of the working ability is, in principle, applicable to various types of disabled persons and those in advanced age. This method is effective for an objective estimation of the synthetic abilites of such man-machine systems as artificial hands.

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We have developed a transfer aid system (named TS-1) for the severely handicapped person. In this transfer aid system two electric motors are used as lifting and traveling power sources, and magnetic powder clutch mechanism as lifting power transmission system. The transmitting torque through the magnetic powder clutch is proportinal to the quantity of current supplied to the magnetic powder. When this system starts to lift the load up and down, the quantity of current to the magnetic powder is controlled to increase or decrease gradually. Consequently, using such a clutch mechanism, the transfer aid system can lift the patient up and down very smoothly. Moreover, the torque for lifting is automatically balanced against the weight of the load. Consequently, when a helper lifts the patient up and down using this system, he can perform the task under the state of nongravitation, as it were. We set up the transfer aid system at the house of a patient with a high spinal cord injury (level C5), and contrived the operation switches, hanger and slings for him so that he could use them himself. As a result, he was able to transfer himself from bed to wheelchair and vice versa without the help of others. In addition, he had been trying to put on and take off his clothes by himself, and was able to take his trousers and underpants off using the transfer aid system and other self-help devices. This system was very useful for helpers, too. By using this system when giving the patient a bath, the burden of helpers has been greatly lightened.

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We have developed three new types of wheelchairs, each of which has an original lift mechanism for the object of use. One is an electric wheelchair for a person with muscular dystrophy or quadriplegia. It can vary the height of the seat by its newly developed lift mechanism from the floor level to a level of 50cm by a couple of switch buttons. At the same time, the mechanism can control the seat from a lifting to a reclining position or vice versa by a single toggle switch. The second is also an electric wheelchair for a person with muscular dystrophy or paraplegia with poor muscular strength. It has two masts along which the seat moves smoothly up and down from the floor level to one limited by the mast height. The last one is a hand-operated wheelchair for a person with paraplegia or lower who has had him limbs amputated. It can control the seat level from floor to the mast height by a light lever handle. These are now practically used and appreciated by the handicapped.

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The pneumatic unit used at the knee joint of the above-knee prosthesis is conceived to be effective for swing-phase control. The check valve and needle valve in the piston/cylinder mechanism, of the unit act as a resistance adjuster or a shock absorber during various phases of the swing action. This provides considerable improvement in stability in walking as well as in maintenance and reliability. The Hyogo Rehabilitation Center (HRC) has developed a pneumatic swing-control above-knee prosthesis, and the authors are working on its sophistication by making use of the adjustability of the needle valve. To provide the basic behavior of the prosthesis with the unit, the mathematical model is built for the unit and the prosthetic system taking account of the mechanical interactions in detail. The adjustment of the needle valve is shown to be considerably sensitive to the response of the prosthesis. In order to verify the theoretical results, a walk-pattern simulator is developed, which provides the whole walking phase kinematics in both stance and swing by servo-mechanisms applied to the above-knee swing and the leg swing elements. The arbitrary inputs to the above-knee motion, including the measured walk-patterns, are fed into a minicomputer. The simulations using the walk-patterns of the above-knee swing of non-patients and amputees are presented for various values of cadence and valve adjustment. It can be easily noticed that a sophistication of the function of this kind of prosthesis can be made by controlling the valve adjustment sequentially to attain a better motion of the leg during the swing phase. In order to see the validity of this idea, an optimum control problem is formulated to the valve adjustment under the criterion that the leg motion generated by measured above-knee data should be close to the desired values. The optimal valve adjustment sequences obtained are shown to be effective and suggest that the plan to make the pneumatic swing-phase control above-knee prosthesis into a sophisticated version is within our reach from the practical point of view.

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There are many designs of friction lock knees which resist the tendency of the knee to flex by a braking action during the stance phase. These knees are good for elderly or feeble amputees, but might interfere with the gait of young and active above-knee amputees, because knee flexion should begin late in the stance phase. He also will not be able to "jack-knife" down stairs and may have difficulty supporting his weight on the prosthesis while lowering himself to a sitting position. Therefore, we need prescription criteria for selection of the knee mechanism. Before preparing the criteria, we need to know the following details-mechanical characteristics of the knees, the gait pattern of the above-knee amputees and the results of the actual use of the knees of above-knee amputees. 1. Physical testing of friction lock knees A testing device which measures the relation between the load and brake moment of the knee mechanism was made. The knees used in the study were Bock 3 R 15 Knee, Bock 3 P 23 Knee, LAPOC Friction Lock Knee and Kolman Safety Knee. All knees except 3 R 15 showed remarkabe constant friction when the weight-bearing brake was adjusted to a sufficiently high level. 2. Pylon study with simulated prosthesis A potentiometer was mounted on the prosthetic knee joint. Tape switches were attached on the sole of both shoes. Strain gauges were attached on the pylon for detecting axial load and knee moment. "Incomplete" knee collapse of the simulated prosthesis was recorded both when the person walked on a leveled floor without a friction lock with reduced alignment stability and when on descending ramps without a friction lock with regular alignment stability. The friction lock knee prevented an "incomplete" knee collapse in both cases above and a substantial level of knee moment was simultaneously recorded, which indicates the working of the friction lock knee.

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In this paper, static motions of multijointed fingers are analyzed, and cooperative control procedures for fingers to locate an object at a desired position and in a desired orientation precisely are proposed. In the analyses, each fingertip is assumed to have a ball-like form and cooperative motions are classified into the next three types according to the fingers used. 1) two fingers of Fm and Fm, 2) two fingers of Fm and Ff, 3) one finger of Fm, where Fm means the finger which has an ability to control both the position of its fingertip and the orientation of its most distal link, and Ff means the finger which has an ability to control only its position. Cooperative motions of two fingers which generate simultaneous finger operation are considered only in the situation when the relative positions of the grasping fingers and the grasped object are maintained as in the initial state. Control procedures resulting from the analyses are applied to a versatile multijointed finger system having a short-range finding sensor at its palm area. Experimental results of such manual tasks as tilting a board, picking up a nut on a floor, attaching the nut to a screw, and its turning have shown that the procedures are useful in performing an autonomous precise handling of an object. It is also shown that the sensor becomes effective for tracing the object from movement while the task goes on.

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In order to control functionally the many degrees of freedom of the artificial multi-finger system, electrostatic clutches which are different from any existing control method, were developed and used in our study. The general properties of the clutch were measured and investigated from the points of view of induced torque, response time of the torque and stability through the cylindrical type of the clutch. As a result, the clutch was controllable with as wide a range as 8.7kg・cm and with satisfactory rapidity of response. As for the stability of the clutch, some kinds of electrodes, such as S 45 C, brass, A 2017 (aruminium), copper gilded, through analysis, were ionized and soluted into the medium, but this resulted in the decrease in the stability of the clutch. In the case of the platinum-gilded electrode, which has a slight ionization tendency, the stability of the clutch was highly improved. The electrostatic clutches, though not superior to other types of clutching with respect to rapidity in response and stability, have a simple disc structure, which makes the driving element smaller and then capable of giving the system more output. Besides, in this study, the control system of induced force using electrostatic clutches were developed and investigated. As a result, it was confirmed that the force was controllable with small error.

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It is essential to find a low-energy consumption system for developing a self-sufficient working robot. "Self-contained working robot" means a robot which has no external energy supply, such as electrical power or communication data. The biggest problem of this kind of "self-contained working robot" is the selection of the energy source. Recently a prototype of a patient care robot has been developed as an example of a "self-contained working robot". Although a combustion engine might be the most powerful energy source for locomotive machines, it cannot be used for the patient care robot since its noise and exhaust gas are not be allowed inside a hospital. Batteries for automobiles can be the cheapest and the most convenient energy sources. In the newly developed patient care robot MELKONG, only two automobile batteries are used as an energy supply to the five motors; one is for a pump of the hydraulic system of the manipulators, the other four are for the driving and steering of the vehicle. This paper shows the new energy saving hydraulic system without any special hydraulic parts. The control unit is composed of the two micro-computer systems. Each consists of an Intersil's 12-bit CMOS micro-processor, ADs, DAs, and DIOs, and all of them are made of CMOS LSIs. The total electricity consumption of this on-board micro-computer resulted in only two watts.

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This paper describes a newly developed method for the automatic traveling of a vehicle. In the methodology of measuring a postural angle of the vehicle, two kinds of parameters of feature extraction are adopted, and these are obtained by the projection of marks which are attached on the surface of road along the route. One is the angle detection value which is calculated by the ratio of Ax to Ap. The Ax represents the maximum width of the projective pattern in the direction of the X axis. The Ap represents the distance between the point on the X axis at which the projective pattern has the largest height in the direction of the Y axis and the smallest value of the projection on the X axis. Another is the pattern-classification value which is calculated by the ratio of the area Aa and the product of the largest width Ax multiplied by the largest height Ay of the projective pattern. The vehicle system can travel from a starting position to a desired destination by applying the proposed method. The route is automatically selected by the system. The route selection is executed by the consideration of three kinds of estimative functions. The first is the distance between a temporary place at an intersection and the destination. The second is a freedom at an intersection. The third is priority, which shows straight, left turn and right turn at an intersection. For a vehicle to start from a starting position and reach a desired destination, 11 kinds of control modes and 16 kinds of marks are considered. Each mark has a different shape and posesses characterized travel functions. The self-decision making capability of the method is compared with that of the human obtained from some examples of the experiments, and the results show characteristics similar to the human capability. The algorithms are written by FORTRAN LANGUAGE occupied about 8K words. The decision making time at each intersection is about 0.1 second and is available in on-line processing.

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The Mechanical Engineering Laboratory started a six-year project of Guide Dog Robot, which we call MELDOG after our laboratory, in the fiscal year of 1977. This project researches fundamental control and communication problems of a man-machine system, i.e. (1) how the robot guides itself by using landmarks set in the town and an organized map of the landmarks and how a blind traveller follows the robot (control of a man-machine system) and (2) how the blind person can find obstacles making use of the visual and ultrasonic sensors on board the robot (obstacle detection by man-machine cooperation). In previous reports a method for guiding a robot vehicle using discrete landmarks (white painted lines on the streets with a length of 2m and a width of 0.15m) and an organized map on the connection of landmarks stored in the memory of the robot was proposed, and its feasibility was demonstrated by both computer simulation and an outdoor experiment with the test hardware MELDOG MARK II. The robot traveled from one landmark to another, setting its steering angle at the value previously stored in the memory of the robot. When it reached a landmark, it adjusted its orientation and position by following the mark using the landmark sensors. Because of this adjustment of position and orientation at each landmark, course error was cancelled at each landmark. It was necessary, however, to set landmarks every ten meters to ensure the guidance of the robot. In order to make the robot travel longer without using the landmarks set on the road, it is necessary for the robot to use natural scenery as an auxiliary landmark. In this report, a method of course control of a travel robot using a direction-controlled visual sensor is proposed, and its feasibility is demonstrated by both simulation study and preliminary experiments with the test hardware. The direction-controlled visual sensor is a micro-computer-controlled CCD camera with a posture-controlled mirror attached, all mounted on a turntable. The mirror is controlled so that the robot can see far and near, and the turntable is controlled so that it can see forward, to the left and right side. The robot detects the edge of the street using the direction-controlled visual sensor, and the course of the travel robot is controlled by the algorithm proposed by using the information about the street.

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In this laboratory, we accomplished static walking in 1972 by biped walking machine WL-5, which is a subsystem of WABOT-1. Since 1973, we have studied biped walking aiming at the accomplishment of man-type smooth walking by a machine model. This time, reproducible "quasi dynamic walking" (the walking in which the trajectory of the center of gravity is stabilized at least once in a stable region during a walking cycle) could be realized by biped walking machine WL-9DR. Its gait is the balance-beam-type quasi dynamic walking on a disturbance-free flat floor; its walking speed is about 9 seconds per step, its stride is about 45cm. The machine model is a man-like biped walking machine with 5 degrees of freedom for each leg, totaling 10 degrees of freedom. Its height is about 1m. and its total weight is about 40.7kg. Each joint is driven by an electro-hydraulic servo system and is controlled by the computer system centering around 16-bit CPU Z8000. The control method is a program control which is designed to continuously feed a previously established preset walking pattern to the machine model. In this paper, we propose a quasi dynamic walking control method with the following two major points. 1) To establish a preset walking pattern, by regarding the machine model as an inverted pendulum model, and analyzing its gait throughout one walking cycle on a phase plane which is composed of the angle of the center of gravity and angular velocity of the center of gravity. 2) To reduce the lag in the system and to improve its follow-up capability, by using the corrected preset walking pattern which is established through the convolution of the reverse transfer characteristics of the system into the preset walking pattern established through analysis and experiments. The experiments by the machine model proves the validity of this control method.

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