A hydraulic drive system can generate a large force and is impact resistant. Thus, robots that utilize hydraulic drive systems have been developed for use in disaster areas. In a hydraulic drive system, it is necessary to design the motion of the robot within the capacity of the pump unit, but it is generally difficult to predict the required flow rate and pressure. Especially for hydraulically driven legged robots, the periodic significant changes in the required flow rate and pressure can make it difficult to select a pump and design the leg operation within pump capacity. Therefore, most operations are not designed in full consideration of the characteristics of the pump. By designing the operation of the robot considering the characteristics of the pump, improvements in energy efficiency and working speed can be expected. In this study, we theoretically derive the relationship between the leg motion of the hydraulic leg robot and the required pressure and flow rate. Based on the results, a method for designing the operation considering the characteristics of the pump is proposed, and its validity is experimentally confirmed.

Ionic polymer-metal composites (IPMC) actuators are popular because they can be driven at a low voltage, possess excellent responsiveness, and can perform soft motions similar to that of living creatures. Conventional IPMC soft robots are manufactured by cutting and assembling IPMC sheets. However, using this conventional process to stably manufacture three-dimensional (3D)-shaped soft robots is difficult. To mitigate this problem, we propose a new method for fabricating 3D IPMC actuators in which several surface electrodes are separately fabricated from a single ion-exchange membrane. We refer to our proposal as the simultaneous 3D forming and patterning (SFP) method. Unlike the conventional IPMC fabrication process, the SFP method requires only one step to fix the ion-exchange membrane to contact masks. First, we briefly describe IPMC actuators, before introducing the proposed SFP method in detail. Next, we describe our investigations of the patterning resolution for the surface electrode using the proposed method. We fabricated two soft robot prototypes using the proposed method. The first robot is a starfish-type soft robot. Its surface electrode can be patterned in a plane using the proposed method, and independent driving is possible by applying voltage individually to the divided electrodes. The second prototype is a sea anemone-type soft robot, wherein surface electrodes can be patterned on a 3D curved surface to form a 3D shape.

Among the various pneumatic actuators, thin McKibben muscles are particularly attractive owing to their high performance in terms of high contraction ratio, high flexibility, and productivity. One of the challenges for thin McKibben muscles and other pneumatic actuators is the fact that they generally need air hoses and air sources like compressors. This necessarily leads to bulky systems. To solve this problem, we propose and study a new approach to driving pneumatic actuators that exploits electrolysis/synthesis of water by a polymer electrolyte fuel cell (PEFC). This method could in-principle have high applicability to thin McKibben muscles. However, one challenge must still be addressed for the realization of an electrically driven thin McKibben muscle: the development of a tube-shaped soft PEFC. This paper proposes an electrically driven thin McKibben muscle with a tube-shaped soft PEFC realized through a flowing non-electrolytic plating method. First, the proposed thin McKibben muscle is briefly described. Then, a novel method for plating a tube-shaped soft PEFC using reflux is introduced, and its fundamental operation is tested. After the evaluation of the PEFC, we report a prototype realization of the proposed thin McKibben muscle. The developed prototype has a length of over 170 mm, a diameter of 4 mm, and high flexibility for bending. Finally, we elaborate on a driving experiment through which fundamental characteristics were experimentally evaluated. The prototype thin McKibben muscle succeeded in electrically controlling contraction and expansion motion with a flexible and bendable structure.

As a part of our research on several different types of Giacometti robots, a 20-m-long, considerably light, and simple robot arm, referred to as the Giacometti arm, is developed in this study. Even though the Giacometti arm is not suitable for precise positioning, rapid motion, and high load capacity, which are the aspects most conventional robots focus on, it is designed for extremely specific purposes such as the inspection of otherwise unreachable regions using a small camera at the arm's tip. In addition, it is designed to be essentially safe even if it falls down or hits an object. This aspect is realized using helium-filled balloon bodies and thin pneumatic muscles. In this paper, we designed new Giacometti arm which is 20-m-long, weighs 940 g, and has 20 degrees of freedom. To realize this long arm, we derived a kinematic model of the 20-m-long Giacometti arm, factoring in the air resistance. We verified the model using the arm, and its utility was confirmed at a mock-up facility.

An octopus arm has no rigid structure, it is mostly composed of muscles aligned in various directions and the nerves. The muscles are roughly aligned in three directions, and by driving the muscles selectively, the octopus arm can perform multiple functions such as the contracting, bending, torsion and stiffness alteration. This study aims at the development of a new flexible robotic arm using thin McKibben actuators mimicking the muscle structure of an octopus arm. The McKibben actuator is a well-known pneumatic artificial muscle, and we have developed extremely thin McKibben actuators by using a braiding machine. In this paper, configuration of the flexible arm is proposed. The developed mechanism consists of thirty two thin McKibben actuators arranged in three directions, axial, radial and oblique, imitating the muscle structure of an actual octopus arm. The fundamental motion of the flexible arm is investigated experimentally. The proposed mechanism performs bending, contracting, torsion movements and stiffness alteration like an octopus arm.

Compressors and air hoses limit the mobility of mobile robots and the use of pneumatic actuators such that small pneumatic actuators, which can be driven without compressors, are strongly desired. We have been developing a new hose-free pneumatic actuator based on reversible gas/liquid chemical reactions. This novel pneumatic actuator neither requires compressors nor air hoses for its source of power because its pressure source is in the actuator itself. In this paper, we present a way to estimate gas generation speed from both theoretical and experimental aspects. We also present a new untethered soft robot, which has this actuator located internally. This robot has three hands and can move them up in 16 s and down in 35 s.

The crank wheel mechanism, consisting of a wheel mechanism and parallel links connected to each wheel, achieved high mobility and efficiency because it has both wheels and legs in a simple structure. However, each prior model of crank wheel mechanism has had shortcomings such as mass oscillation or fragile structure. In this paper, we propose a novel crank wheel mechanism, the “Eccentric Crank Rover”(ECR), which is an enhanced crank wheel mechanism with eccentric wheels. The eccentric wheels increase the under-body clearance, and change the body trajectory from straight to trochoid curve, which has the same shape as the crank legs but opposite phase trajectory. Thus, the body itself acts as a “second” crank leg. We experimentally confirmed higher step climbability, larger clearance, and lower cost of transport than other models such as normal wheel model, eccentric wheel model, and crank wheel model without eccentric wheel.

An amphibious all terrain mobile robot is required for disaster response tasks. In this paper, we propose “R-Crank”, which has a simple four wheels driving configuration with crank links, connecting to ipsilateral front and rear wheels so as to form parallel four-bar linkage systems. The crank links act as legs because their trajectory with respect to the ground become trochoid curve, which is commonly used as leg trajectories for a legged robot. These links achieve high terrain adaptability while maintaining simple structure of the wheeled robot. We developed a prototype model and carried out basic experiments. The robot achieved to climb 0.3 m of a step(76.9% of the wheel diameter), stairs and a snowy slope. In addition, we propose amphibious structure of crank links by installing multiple rigid paddles. The propulsive force generated by the crank links was measured and empirically derived the optimum parameters by using a small-sized experimental apparatus. Finally the robot equipped with the amphibious crank links achieved propulsion on water at 0.13 m/s. We also verified that the robot achieved going up and into water through stairs.

Generally, wheel mechanisms are inferior to a tracked or walking mechanism in terms of step climbability or traversability in rough terrain; however, they are superior in terms of energy efficiency, structural simplicity, and carrying capacity. This paper proposes a new wheel mechanism, the swing-grouser wheel, which can climb high steps (especially in low friction environments) and has high energy efficiency. In addition, the swing-grouser wheel can climb regardless of the body inclination. Its merits are compared to the results of prior studies. Furthermore, the performance of the swing-grouser wheel was confirmed using a real device experiment and a 2D physics simulation, and improved using a full search of the parameters of the swing-grouser wheel. As a result, one improved parameter resulted in climbing at over 68% of the wheel diameter in a low friction environment; additionally, the energy efficiency was better than that of the previous model.

Pneumatic actuators have been widely utilized in industrial robots and in welfare apparatuses, for example with their advantages of light weight, low cost, safety, and high compliance. However, driving them needs not only the air supply line from compressor but also many electrical lines from controller to valve, making the pneumatic drive system complicated. This research proposes a new control method for the deletion of electrical control lines in pneumatic mechatronics. This method needs two technical challenges; acoustic communication system and power supply device for each local module. First, we explain the outline of a multiplex pneumatic actuator drive method. Secondly, acoustic communication system using a microcomputer (PSoC) is shown, where carrier frequency is optimized with a basic experiment. Thirdly, the design of a power supply device is shown with experimental results. Finally, a multiplex pneumatic actuator drive method is constructed with the acoustic communication system and power supply device. This prototype system works very well to show the great potential of this proposed control method. It controls successfully three pneumatic cylinders independently which are connected with an air supply line of 10[m].

In recent years, Japanese society has been aging, engendering a labor shortage of young workers. For a robot that is often in contact with people and which must provide safety and flexibility in nursing and welfare, the development of a soft, lightweight, and compact actuator has been sought. Particularly robots that are intended for use in the field of medical care and welfare should be safe when functioning around humans because they often come into contact with people. Therefore, a tendon-driven balloon actuator (balloon actuator) has been developed for a robot hand to be used in such environments. For this study, we developed a stroke control system for a balloon actuator using a predictive functional control (PFC). Predictive functional control is one model based on a predictive control (MPC) scheme, which predicts the future outputs of the actual plant over the prediction horizon and computes the control effort over the control horizon at every sampling instance. This paper reports the PFC control performance of the balloon actuator. We compared the control performance for the actuator with that of a PFC and PID control system.

The aim of this research is to realize a functional adhesive robot skin with integrated micro suction cups, which has two new functions involving adaptive adhesion to rough/curved surfaces and anisotropic adhesion. This skin can be applied to various robot mechanisms such as robot hands, wall climbing robot feet and so on. In this report, the robot skins have been successfully developed to realize the higher adaptive adhesion by modifying materials and integration density of suction cups. The suction cups on 10mm × 10mm area realize the adhesion to surfaces with 145μm RMS roughness and with gap of 900μm in height.

This study aims at development of a multi-directional bending mechanism with thin and long body driven by fluidic rubber actuators. Generally bending mechanisms with fluidic rubber actuators can have advantages of smooth and continuous motion, however because of their low stiffness it is difficult to generate high output force. To solve this problem, we have proposed a novel bending mechanism combined with contracting and extending rubber actuators. By bundling rubber actuators with different types, the developed bending mechanism can have the high stiffness. In this report, optimized extending and contracting rubber actuators are made basis on a McKibben actuator, then they are combined to be the bending mechanism. Experimentally stiffness of the mechanism is measured and is compared with a bending mechanism bundled with same motion type actuators. Resulting high stiffness can be recognized by the proposed mechanism. Additionally, a very long bending mechanism, which is 7m in length, is developed and its motion is demonstrated.

The goal of this research is to develop a functional adhesive robot skin with micro suction cups, which realizes two new functions: adaptive adhesion to rough/curved surfaces and anisotropic adhesion. Both functions are realized by integration of asymmetric micro cups. This skin can be applied to various robot mechanisms such as robot hands, wall-climbing robot feet and so on as a kind of robot skins. This paper especially reports the concept of this adhesive robot skin and its fundamental characteristics. The experiments show the developed skin realizes novel characteristics, high adhesion even on rough surface and anisotropic adhesion.

Intelligent Pneumatic Actuators (IPA) is a new generation of actuator for Research and Development (R&D). The purpose of this paper is to present the System Identification (SI) technique and procedure for the IPA system. System identification is used to obtain the mathematical model (transfer function) of the IPA system from the measured experimental data. Flow for the SI procedure starts with experimental setup, model structure selection, model estimation, model validation and finally testing with basic controller to prove the operation of IPA system. Auto Regressive with Exogenous Input (ARX) model is chosen as model structure of the system. Based on the input and output data of the system (model validation), best fit criterion and correlation analysis of the residual is analyzed to determine the adequate model to represent the IPA system. The result from SI model shows linear discrete model in order to obtain a discrete transfer function for the IPA system.

There are many big challenges for manipulation in ultimate temperature environments. Examples of these are in material sciences and industries. For example, steel industries desire new methods for direct handling of materials in temperature higher than 1000 degree Celsius while material scientists desire new method for handling specimen in helium temperature, where higher-quality analysis can be carried out with very low thermal noises. However, conventional actuators don't work in such environments because of their low thermo-stability and more essential reason of the loss of the magnetic and piezoelectric properties of actuator materials. It us well known that magnetism and piezoelectricity completely disappear in temperature higher than Curie-Point, for example. This report proposes a new working principle of actuators for the uses in very wide temperature range. It is driven by volume change associated with phase transition of working fluid. We propose the principle of this actuator and show the possibilities of the actuator design including the possible selections of temperature-resistant materials and working fluids in various temperatures. In addition, as the first step of this research, we designs the first prototype actuator, working successfully at 180 degree Celsius utilizing liquid-vapor transition of water and the basic experiments results, which shows the great possibility of this actuator.

Recently, colonoscopy has become much more important with increasing number of colonic diseases. However, the inspection time depends on the doctor's skill strongly. In this research, we aim at development of a tube type rubber pneumatic actuator for assisting insertion of a large intestine endoscope. This actuator can be wound around endoscopes in a spiral configuration. In previous paper, two types of actuator were developed and some experiments were conducted. However, there were drawbacks, one actuator could not generate enough output, and the other one was difficult to mount on endoscopes. In this paper, novel actuator has been designed by non-linear FEM (Finite Element Method) to realize high mountability and drivability. The actuator is configured with three air chambers, and by applying pneumatic pressure to each chamber in proper sequence, elliptical motion of the actuator has been confirmed by non-linear FEM analysis and experiments using motion capture system. Moreover the self propelling velocity and the traction force have been increased compared to previous actuators and effectiveness of this actuator has been confirmed from the phantom experiments.

Our research group has investigated various kinds of soft mechanisms for many years. Through these researches, several soft rubber actuators driven pneumatically have been developed. The typical one is FMA (Flexible Microactuator), which realizes continuous bending motions like a human finger. In addition, we are recently interested in several novel functions appeared on soft mechanism surfaces such as repellency, hydrophily, friction, structural color, and adhesiveness, which are realized with micro scale soft structures fabricated on the surfaces. We believe novel additional functions can be realized by utilizing the deformability of the soft structures. In this paper, micro grating structures made from silicone rubber are reported. Because of its elastic property, it can realize changing structural color. The experimental results show that beautiful color change can be observed. We fabricate a soft micro grating structure on FMA and confirm the appearance of structural color, which changes in following FMA's motion. This color change indicates distributed information of the strain of FMA, which may be used for servo control of FMA in the future.

We have developed a hydraulic McKibben artificial muscle which realizes great force density approximately ten times larger than the other conventional actuators. In this paper, we have applied this muscle to a power robot hand. The hand finger consists of metal links and the muscles. The contraction of the muscles generates the bending motion of the fingers. This hand has large holding capacity and shape adaptability to grasp objects. The experiments show that maximum holding force of the hand is 5000N. It can hold three types of different shaped objects; cylindrical objects of φ 267mm and φ 165mm in diameter and a square cross section of width 200mm in side. This hand can be applied to various applications, for example rescue robots in disaster area and forestry industry.

Colonoscopy is an important medical action to detect disorders like colon cancer. However generally it is difficult to insert a scope into the colon, because the colon is flexible and complex shape. This study aims at development of an actuator which can add propelling ability to a colonoscope. We focused on rubber pneumatic actuators, because advantages of them, for example, high compliance, low cost, water proof, and so on, agree with the required properties of medical devices. In previous paper, we designed a novel rubber actuator consisting multi air chambers by using nonlinear FEM (finite element method). In this research, we fabricated the actuator employing the design; whose cross section is about 5mm × 5mm and length is over 100m, by extrusion molding method successfully. The deformation characteristics of the actuator were clarified by a motion capture system. As a result, elliptic trajectory which leads propelling motion was confirmed. In addition, transportation of a dummy scope was achieved by winding two actuators.

Pneumatic actuators have several advantages such as light weight, safety, low cost and high compliance. They have been used in many areas such as industrial robots, rehabilitation tools, haptic devices, and medical/welfare robots. Pneumatic actuators are generally used in multi-DOF pneumatic system and have complicated systems that include a compressor, air tubes, and pneumatic valves with electrical wires. This research proposes a new control method for a multiplex pneumatic transmission constructed with special resonant valves and driven independently with air vibration in air supply tube without electrical wires. The control method simplifies the driving system and is effective for pneumatic systems having many degrees of freedom. In this paper, the development of a prototype model of the resonant valve is described. In addition, two control methods, which are a superimposing method and a time-sharing method for multi-valve control, are proposed and evaluated. Independent control of four pneumatic cylinders is realized.

In medical and biotechnology fields, soft devices are required because of their high safety from low mechanical impedance. FMA (Flexible Microactuator) is one of the typical soft actuators. It consists of fiber-reinforced rubber structure with multi air chambers and realizes bending motion pneumatically. It has been applied to robot hands, robot legs and so on. High potential of FMA has been confirmed by many experiments reported in several papers. However in fabrication process of the actuator, it is difficult to embed the reinforced fiber in the rubber structure. In this study, we aim at development of a fiber less FMA realizing quite large motion, which can be said curling motion, and a soft hand using the actuators. We design the actuator without fiber using nonlinear FEM (Finite Element Method) and derived efficient shape. The actuator is fabricated through micro rubber casting process including micro machining process for molds, micro vacuum rubber molding process and rubber bonding process with surface improvement by excimer light. Basic driving experiments of the actuator showed that it realized curling motion which agreed well with FEM results. And the actuator could grasp a fish egg without breaking. Additionally, we made a soft hand consisting of three curling actuators. This hand also could be manufactured by simple casting process. The developed hand works opening and closing motions well.

The goal of this research is to realize a new type of physical human-machine interface. In this research, Active Polyhedron can treat virtual three dimensional continuums having many force output points. Active 80-faced Polyhedron can treat virtual objects that are more complex than Active Icosahedron which was previously developed. Towards realizing the overall hardware parts, 120 pieces of new and compact intelligent pneumatic cylinder with length measurement and communication function are designed and constructed. Communication and control system to control input-output data between PC and 120 cylinders was confirmed. Three experiments were carried out, which are position control of the cylinder, shape input experiments and spring motion experiments. In the shape input experiments, inputting shape information of the Active 80-faced Polyhedron to PC is realized. On the other hand, the spring motion experiments establish the stiffness function by changing stiffness coefficient of each intelligent cylinder where the operator can feel its difference. Both experimental results show the effectiveness of the Active Polyhedron for a new human machine interface.

The final goal of this work is the development of functional rubber sheets with micro rubber structure such as friction free, adhesion, and impact adsorption rubbers, etc. In the previous report, we reported a micro rubber structure realizing flexible passive walking with 3 v-shaped units consisting of 4 legs to achieve very low friction. In this second report, we show the miniaturization and integration of this structure to realize a rubber sheet with 64 legs by micro rubber molding process using stereo lithography method. The prototype is designed and fabricated, and tested. Under some conditions, the 64 legged rubber sheet realizes flexible passive walking on a sloping road successfully.

A low-profile micro ultrasonic motor has been designed and fabricated. This motor has two sector shaped vibrators. The vibrators generate elliptical motion by the 1stlongitudinal mode and 2ndbending mode. They are supported by planar elastic structure that combined with preload mechanism. Three types of preload systems were designed and evaluated. The thickness of one type was 0.6 mm. These vibrators have been oscillated around 340 kHz. The maximum rotation speed was 2.4 x 103rpm and the maximum starting torque was 98.8 muNm when the applied voltage was 20 Vp-p.

The final goal of this research is to develop functional rubber structures such as friction free rubber, adherent rubber, and shock/ noise absorption rubber, which will work as a flexible rubber robot body, a soft robot skin and a sole of foot. This paper reports the first step of this research on a micro rubber structure realizing multi-legged passive walking, which shows a great potential of realizing friction free or self walking rubber with micro rubber legs. A prototype of the micro rubber structure with many passive legs are designed, fabricated, and tested. The rubber successfully realizes passive walking on a sloping road.

This paper shows a new design and prototyping method for a bending pneumatic rubber actuator and its application to a soft-bodied manta swimming robot. The design is based on optimal design using non-linear finite element method, in which geometrical and material non-linearity are considered and fabrication process is based on a rapid and efficient prototyping system using a CAD/CAM based rubber molding process. In this paper, the characteristics of several possible actuators are analyzed and evaluated to lead to an optimal actuator design. The actuator works very well with smooth and soft motion. The manta swimming robot in which the developed actuators are embedded is also designed based on non-linear finite element method. The developed manta swimming robot is made only of rubber and it swims in water smoothly as if it was a living fish. The experimental results of the manta robot motion show that good agreement with those of analytical results.

The aim of this research is to evaluate the driving performance of a cylindrical micro ultrasonic motor which has a casing diameter of 1.8 mm. The micro ultrasonic motor is driven by a cylindrical piezoelectric vibrator, which has a diameter of 0.8 mm. We evaluated the driving performance of the cylindrical piezoelectric vibrator when two different types of rotors were used and two different vibration modes were oscillated. When the frequency and the applied voltage were 314.5 kHz and 30 Vp-p, the maximum revolution speed and the starting torque were 9.6times103rpm and 5.5 muNm, respectively.

A new pneumatic linear actuator made of a thin flexible rubber is developed for locomotion in narrow paces. The actuator is named “tetra chamber actuator”. This new actuator has an ability of object transportation and locomotion. The actuator was designed based on non-linear FEM analysis considering geometrical and material nonlinearity, fabricated and evaluated. The working principle of this actuator is based on a traveling elastic deformation wave drive and the actuator was designed to generate large track of the deformation and to have an ability of bidirectional propelling. The actuator shape was designed in detail using nonlinear FEM analysis and was fabricated by CAD/CAM system based on the results of analysis. The prototype is 107#x00D7;10mm in size. The experiments were made about its basic characteristics and object transportation ability. The prototype generates the motion about six times larger than that of conventional similar actuators to show its great potential.

Recently, a variety of soft actuators have been developed. However, applicable sensors such as potentiometers and optical encoders generally have high stiffness. Therefore, a soft actuator loses its compliance when these sensors are used with the actuator. Thus, in this research, we have developed a flexible displacement sensor that can keep the compliance of a soft actuator. The fabricated flexible displacement sensor is composed of piezoelectric polymer, conductive paste and base rubber. Piezoelectric polymer: poly(vinylidene fluoride- trifluoroethylene) [P(VDF/TrFE)] was used for the detection of displacement and conductive paste was used for electrodes. An intelligent FMA (flexible microactuator) was developed by attaching these sensors. Displacement of the intelligent FMA and the sensor output voltage were compared, and sensing features were evaluated. Furthermore, servo control of the intelligent FMA using the sensor was performed. As a result, high positioning accuracy was verified.

Recently, a variety of soft actuators have been developed. However, applicable sensors such as potentiometers and optical encoders generally have high stiffness and when they are used in a soft actuator, the actuator loses its compliance. To solve this problem, a flexible displacement sensor has been developed. This sensor was fabricated by depositing a conductive paste onto a rubber seat. Paste injection was utilized in the fabrication process of the sensor, and precise control of thickness, width and pattern of the conductive film and deposition onto a curved surface was realized by this system. Firstly, an experiment on a flat-type flexible displacement sensor was conducted to evaluate and improve the sensor. The experimental results showed sufficient linearity and detecting range. Then, an intelligent FMA (Flexible Microactuator) was fabricated by depositing the conductive paste onto the surface of an FMA. A servo control system for the intelligent FMA was set up, and high positioning accuracy was confirmed by a servo driving experiment.�

The goal of this research is to develop a new type of haptic interface termed "active polyhedron", which realizes a physical human-machine interaction with virtual continuum objects in PCs. Active polyhedrons are polyhedron-shaped linkage mechanisms. In this paper, we deal with an active icosahedron consisting of 30 intelligent cylinders, which were specially developed for this purpose. In previous reports, the mechanism and kinematics of an active icosahedron and a simple force-presentation method using on/off pneumatic valves were given. In this report, a new force-presentation pneumatic-control system using pressure-control valves, which allows a highly accurate force presentation capable of handling complex continuum objects, and a new force-presentation algorithm, which applies to an apex of the polyhedron are described. These were applied to the active icosahedron. The experimental results showed that the active icosahedron was successful in realizing physical human-machine interaction, with which operators could change the shape, feel and compliance of virtual objects in a PC as if they actually touched them

Inserting an endoscope into colon requires very technical procedure and it is difficult in some cases even for experienced doctors. Although active colonoscopes have been researched, these instruments are still in the development stage. Mechanisms for this application are required to be soft enough not to injure the colon wall and being deformable enough to adapt to the curves of the colon. In addition, the mechanisms must generate distributed force adequate for traveling. These requirements are difficult to be satisfied using conventional mechanisms and actuators. We have designed and developed two types of new driving mechanism using pneumatic rubber actuators and made their feasibility tests. One mechanism is "thin tube wave generator": introducing pulse pneumatic flows to a thin rubber tube causes traveling deformation waves on the tube surface, which drives an object placed on the tube. The other mechanism is "round bubbler": a rubber tube which has four chambers in it is wound around the colonoscope to cause traveling deformation waves on the scope surface by sending pneumatic pressures to each chamber sequentially. In this paper, first, we discuss the driving mechanisms, pneumatic control systems, and basic characteristics of these two mechanisms. Then, based on the basic experimental discussions, we fabricated special rubber mechanisms to fit around a conventional colonoscope, and conducted insertion experiments using an intestinum model and an existing colonoscope under various conditions. The experimental results are very promising

We developed rescue robots and tools that are driven by hydraulic actuators. They are small-sized, have simple mechanisms, and are suitable for heavy-duty rescue operations. This report shows the results of field tests carried out to verify the possibility of the two rescue robots we developed; we named them the Jack Robot and the Cutter Robot. We classified disaster situations into three categories: collapsed house cases, collapsed building rubble cases, and traffic accidents. We used the two robots in test situations that simulated these three disaster scenarios. As part of the experimental results, we found that there is a great potential for the use of these high-powered small rescue robots in disaster areas.

The aim of this study is to develop an intelligent McKibben actuator with an integrated soft displacement sensor inside, so that displacement of this actuator can be controlled without having any extra devices attached. In addition, the high compliance which is a positive feature of the McKibben actuator is still conserved. This paper consists of four main parts. First of all, different types of soft displacement sensors made out of rubber were composed, and tested for their functional characteristics. Secondly, the intelligent McKibben actuator was developed with the soft displacement sensor incorporated within. Then, experiments of the position servo control with a single intelligent McKibben actuator were carried out. At last a robot arm mechanism was designed with two intelligent McKibben actuators, and those experimental results showed a great potential for its future applications.

A new type of stepping motor, named electric nutation motor was developed. The aim of this research is to develop a new stepping motor with high torque. Based on the magnetic field analysis using finite element method, theoretical value of the electromagnetic force was obtained. Magnetic path was designed and optimized. The force of the electromagnet was 60 N with the current of 0.3 A. The motor was found to have the maximum torque of 0.64 N/spl middot/m, the maximum speed of 4.3 rpm, and positioning accuracy of 1,248 step/rev.

In this paper, we propose a new type of haptic interface, named active link mechanism. This device realizes physical man-machine interaction (PMI) between machines and persons. Two prototypes were developed to demonstrate the potential of the active link mechanisms. Developed interface devices are an active tetrahedron and an active icosahedron. Nine-DOF micro spherical joints and pressure control pneumatic cylinders were developed to realize the active tetrahedron, while fifteen-DOF micro spherical joints and intelligent pneumatic cylinders were developed for the active icosahedron. The tetrahedron successfully realizes "virtual touch"; the operators feel actions, forces, and shapes of the virtual objects in PC and also move and deform them. Real time PMI is realized by building the developed devices into MSC.Visual-Nastran4D. MSC.VisuaI-Nastran4D is a mechanism analysis software, which can make motion analysis in real time. The active icosahedron also realized dynamic interaction with virtual objects in PC, showing the potential of the devices as a haptic interface.

The purpose of this research is to realize a small robot which can negotiate pipes whose diameter varies widely during the robot's course. A new in-pipe locomotion mechanism named "snaking drive" is proposed in this paper and its potential and fundamental characteristics are shown with experimental data of the prototype model. First, in the sections 2 to 5, the basic traveling characteristics of the snaking drive mechanism are discussed: a theoretical formula of the fundamental characteristics and control algorithm are derived, the motions of the robot are simulated on a PC, and the prototype model was designed, developed, and tested. Next, in the sections 6 and 7, additional control algorithms for the front link are derived. They are necessary for steering at T-branches and L-bends of pipes, and also for camera view stabilization. Their performances are also shown by software simulation and experiments. The prototype robots moved in pipes whose diameter varies between 55 mm to 331 mm with the maximum speed of 22 mm/s. The paper also shows that the prototype negotiates T-branches and L-bends of pipes with inspection capability through a camera mounted on the robot.

A new type of pneumatic stepping motor, named pneumatic nutation motor, was developed. This motor achieves stepping positioning of 720 steps/rotation without any electrical devices or sensors mounted on the servo mechanisms. This makes the motor possible to be used under hazardous conditions such as in water and in strong magnetic fields where conventional electromagnetic motors cannot be used. The motor torque is so big that the motor can be used as a direct motor. In this report, the driving principle and design of this motor are presented. Its characteristics are analyzed experimentally and theoretically. The motors were applied to a parallel linkage mechanism with six degrees of freedom. The mechanism shows that the pneumatic nutation motors can be used as a direct servo motor for robot mechanisms.

A direct-drive stepping motor based on a new principle is reported. The features of the motor include: 1) high torque (4-20 times higher than that of the same-sized conventional electric motors); 2) high stepping resolution; 3) light weight; and 4) simple structure. The motors are suitable for robots in new applications such as microrobots and human-care robots. The mechanism and theoretical analysis for the motor are presented. Two models, which are designed for pipe-inspection microrobots and for human-care robots are shown respectively.

A new, pneumatic rubber actuator, named bubbler, realizing linear motion has been designed, developed and tested. The bubbler consists of a silicone rubber slab, and its inside is divided into twelve chambers each having a square cross section. If pressure is applied to successive chambers sequentially, the surface of the bubbler produces a linear traveling wave. It can be used for a mobile robot base or for a conveyor. Experimental results are very promising. The walking speed of the prototype, 63 mm/spl times/60 mm/spl times/9 mm in size, was found to be 3.6 mm/s and the load-to-weight ratio in the order of 40:1. A demonstration board using two bubblers works as a mobile robot base realizing forward/backward and steering motions.

A flexible microactuator (FMA) driven by an electropneumatic (or electrohydraulic) system has been developed. The FMA has three degrees of freedom, pitch, yaw, and stretch, and these are suitable movements for miniature robotic mechanisms such as fingers, arms, or legs. The construction is of fiber-reinforced rubber, and the mechanism is very simple. Gentle miniature robots with no conventional links can be designed using this design. The FMA's basic characteristics and its applications to certain robot mechanisms are presented. Serially connected FMAs act as a miniature robot manipulator. The kinematics and control algorithm for this type of robot are presented. FMAs combined in parallel act as a multifingered robot hand, with each FMA representing a finger. An algorithm for the cooperative control of such FMAs, the stable region for holding, and its performance are presented.>