We present a novel application of the MEMS technology to a non-contact gripper using arrayed spiral air flows, aimed at the mitigation of flow-induced vibration of levitated objects. For robot end-effector dealing with fragile objects such as silicon wafers and solar panels, we employ an air flow-based gripping technique with continuous air-blowing, which would enable damage-free handling without contamination. We design the gripper based on the concept of distributed forcing with arrayed spiral-flow chambers and open holes. In this study, we design and fabricate MEMS-based grippers in a size of 5 inch square. It is shown that the attraction force is successfully obtained by the negative pressure of a spiral flow in each chamber, and that open holes play an important role in eliminating the interaction between the neighboring chambers.

View full abstract

Recently, rescue robots to search disaster sites are actively developed. In order to reduce the risk of the secondary disaster, information collection should be safely and quickly realized in the polluted environment stricken by the NBC terrorism. Therefore, remote control of rescue robots for the information collection is very important. A current remote control interface for rescue robots most commonly used is a gamepad. However, there are some problems, such as the complexity of the control technique, the guarantee of a steady place for setting up a monitor display, etc. The aim of this study is to develop a portable and easily controllable GUI by using a touch panel. The usability of the GUI is veri ed by comparing the GUI with a gamepad in a testing environment.

View full abstract

We have proposed Flexible Mono-tread mobile Track (FMT) as a mobile mechanism for hazardous environment such as disaster area. FMT has only one track which can flex in three dimension. Generally speaking, one has to teleoperate robots under invisible condition. In order to operate the robots skillfully, it is necessary to detect not only condition around the robots and its position but also posture of the robots at any time. Flexed posture of FMT decides turning radius and direction, it is very important to know its posture, accordingly. FMT has a vertebral structure composed of vertebrae as rigid body and intervertebral disks made by flexible devices such as rubber cylinder and spring. Since the intervertebral disks flex in three dimension, it is not easy for traditional sensors such as potentiometers, rotary encoders and range finders to measure its deformation. The purpose of the paper, therefore, is to measure flexed posture of FMT using a new flexible displacement sensor. We prove that the flexed posture of FMT with five intervertebral disks can be detected through experiment.

View full abstract

As for the robot used in a disaster and the terrorism spot, it can be steered remoteness from the safe area where were several hundred meter distant, but there are many cases that it acts with a rescue team, and supports various work from around. In such situation, it loses a unit power that member alone is cut only for the operation of the robot, and it is a problem on work efficiency. Therefore we have studied on a method using hand signals to steer the robot only with one hand so that one member could perform the operation of the robot and other work in parallel. In this study, we produced a cheap user interface to input hand signals, and investigated the optimum hand signals pattern by operating a robot in the virtual space with a software "Virtual Battle Space2" using serious game technology.

View full abstract

As for the robot used in a disaster and the terrorism spot, it can be steered remoteness from the safe area where were several hundred meter distant, but there are many cases that it acts with a rescue team, and supports various work from around. In such situation, it loses a unit power that member alone is cut only for the operation of the robot, and it is a problem on work efficiency. Therefore we studied on a method using hand signals to steer the robot only with one hand so that one member could perform the operation of the robot and other work in parallel. In this study, we produced a cheap user interface to input hand signals, and confirmed it was more effective than the steering wheel for operating a robot in the virtual space with a software "Virtual Battle Space2" using serious game technology.

View full abstract

Captive balloon systems named InfoBalloon have been developed for collecting and distributing disaster information. This paper proposes a method for making an image archive with direction and time information. And also an idea for searching and showing image information for users is discussed. Information about direction is put by data which is estimated using quaternion rotation and SIFT matching on a virtual sphere centered on a pan-tilt camera. To classify images, the sphere is subdivided and each image is set out. Image searching is processed using the classified images. Search range is set by user and images in the range are shown. And also we will propose a method for estimating oscillation of InfoBalloon using the gap of the specified value and the value which is estimated.

View full abstract

This paper describes a method for removing of obstacles in the images by multiple cameras. Acquiring information of remote location is needed to operate robots in a remote location. For example, an image by camera is effective in remote control. However, there is a problem that images from camera on front of FMT are hindered by the FMT's crawler. To use them as image for control, removal of crawler in the images is necessary. The proposed method generates the images without crawler by multiple cameras and image processing. Then the method uses edge and difference between some images to detect crawler. We confirmed the availability of the proposed method by experiments.

View full abstract

In recent years, some tracked mobile robots have been developed that run over irregular terrain with remote control. They have a number of DOF to improve their mobility and are capable of cross stairs and steps. However, their remote operations are complicated, because they are controlled by operators using a control pad such as used in computer games or toys. So, we propose an intuitive remote control system, using the conventional master- slave operation for a novel crawler robot "KUROGANE". KUROGANE consists of a typical crawler, plus a human-like upper body. We operate it by means of a wearable remote controller. Thus, the KUROGANE has achieved the ability to crawl swiftly over rough terrain.

View full abstract

Passive mechanism, which runs through uneven terrain and steps with a simple operation, can make it possible to simplify its operation procedure. This study examines the running ability of Rescue Robot BLUE-R2 using passive mechanism. BLUE-R2 cannot climb stairs without a crawler unit operation by the operation driver. In order to improve this mobility, we placed center of gravity to the front part of robot by inversing a back crawler unit. This change made it possible for the robot to climb stairs. Moreover, we have found that the robot climbed stairs more efficiently by installing a elastic between the crawlers and making them follow each other. These results indicate that the position of center of gravity and the movement between crawlers are crucial factors to mobility improvement of a rescue robot with passive mechanism.

View full abstract

For tracked vehicles with "sub-crawler" moving over rough terrain,it is important to control the contact force between sub-crawler and environment(Soft-contact-system). However,there are some problem to achieve Soft-contact-system. For example , we have to estimate friction torque come from gear reducer to estimate the contact force. In this paper, the authors propose a Soft-contact-system and solve some problem.

View full abstract

The rescue operation of the avalanche victims is accompanied with the second disaster risk. In this study, we are aimed for the development of the rescue robot to search for the avalanche victims. In late years the person climbing the snowy mountains carries wireless communication device called an avalanche beacon. We created the mobile robot to move on the snow and the receiver to receive information from the avalanche beacon and tested evaluation experiments. This paper describes the details of the rescue robot and suggests the method to estimate relative position between the robot and the victim.

View full abstract

We have been researching on an information gathering robot. Before a rescue team enters to save the people who encountered the damage in a disaster and the terrorism spot safely, this robot searches for a safe course for the rescue team, dangerous equipments and the victim. We have developed a small light weight and portable robot which can enter narrow space. This robot has a wheel mechanism driven by each friction of which a transmission is simple. In this study, we confirmed the maneuver performance of one robot on various ground, and propose a coupling of multiple robots to improve that performance more.

View full abstract

We have been researching on an information gathering robot. Before a rescue team enters to save the people who encountered the damage in a disaster and the terrorism spot safely, this robot searches for a safe course for the rescue team, dangerous equipments and the victim. In this report, we propose a small, light weight and portable robot which can enter narrow space. This robot has extendable spiny wheels of which diameter be able to change from 0. 12[m] to 0.24[m] to adapt rough terrain. We produced a prototype of this robot and confirmed the motion of this mechanism experimentally.

View full abstract

Many rescue robots moving in disaster area are obtaining trust because of using device of high performance. However, the robot system become costly and complex because of using it. On the other hand, there is a system design to make the sensor become independent as a disposable possible unit. There is a spheroidal sensor system that governs the sensor in a small case. The spheroidal sensor case, disposable and the jump movement are possible. The goal of this research is to give the spheroidal sensor unit simple hopping mechanism and to spread range of diffusion of the sensor unit. This paper describes caoncept of the sensor unit system and production of small hopping spheroidal sensor unit.

View full abstract

A sarin gas incident occurred in the Tokyo subway system on March 20, 1995. This fatal gas attack caused sicknesses to many passengers. Since the disaster broke out under the ground, the main job of rescue personnel was to transport victims on stretchers to a first-aid station on the ground. So, we research and development the rescue support stretcher robot for a heavy casualty disaster in underground areas or at stations can be handled in a quick, effective manner. The stretcher robot is expected to help firefighters achieve efficient rescue operations. In this paper, we introduce the rescue support stretcher system for going up and down the stairs. And, we propose the technique of vibration suppression. Finally, we examined the effectiveness of the robot by the experiment.

View full abstract

In order to develop available rescue devices, it is necessary to make them run in various types of rubble and evaluate their mobility statistically. However, the evaluation under collapsed houses in real world is not enough. Therefore, our research group has enabled to create a lot of piles of virtual rubble model by physical simulation and to get their quantitative characters by methods based on geometric models. This study has established a method to structure internal working space for rescue devices as a path network. In addition, this study suggests a method to evaluate largeness of inside space through which rescue devices can access from outside space of rubble with Gareki-space Migratory Difficulty Index.

View full abstract

At the time of earthquake, it is important to obtain information on the internal structure when we carry out a rescue operation. For example, position of free space and fragile part in the collapsed houses. However, it is difficult to know the internal structure from external information alone. Therefore, this study aims to establish of a method for estimating the internal structure of collapsed houses. This study suggests an evaluation method with the living space deformation using Space Deformation Index. Space Deformation Index is evaluation index to evaluate compression or/and deformation of the living space, based on the analysis of the digital rubble model.

View full abstract

This study discusses the search and rescue mobile robot which is aimed to go through narrow and curving routes and pipes inside the collapsed houses. This robot is inspired by the action of the octopus drawing out its arms. Since it uses the part of the arm that was drawn out as support for its advancing motion, it is expected to carry a camera without depending on the size of pipes. To realize this action, this robot is composed of a flat tube and a slider named Λ-drive. In Λ-drive the tube is bent, forming a buckling point on it, which helps to cut off the fluid passage in order to provide the driving force to the slider when pressurizing one side of the tube. Finally, it is experimentally verified through experiments that this robot is able to go through some narrow and curving pipes.

View full abstract

Recently, the large earthquake has occurred. In order to find and save victims even one, many researches and developments of the rescue robot have been done. In such studies, most of the rescue robot used the electric actuator for travelling. In those cases, there is a possibility of getting an electric shock because of electricity. Comparing with electric actuators, the pneumatic actuators and devices can make the robot stronger against the electric shock and physical shock. In this study, we aim to develop the search type rescue robot with flexible structure. We propose two types of robot. First, we propose and test a light-weight and compact search type rescue robot using the flexible pneumatic cylinder. We also propose and test the robot using a pneumatic motor and the long stroke type artificial rubber muscles. This paper describes the structure and the principle of operation of the tested robots.

View full abstract

In this study, a new method of steering for the burrowing inspector is proposed, which is aimed to move into the soil on its own and inspect survivors more efficiently. The burrowing inspector is useful at landslide disaster sites, which occur after earthquakes, heavy rain, and accidents. The proposed propulsion method is inspired in the movement of a mole, which advances efficiently by pushing aside the soil with the shoveling motion. However, previous method of steering was not effective in some cases, and it was only for 2-dimensional steering. To solve these problems, characteristics of the steering are verified through additional basic experiments. Then, a new method of steering is proposed, and its efficiency is verified through experiments. Moreover, a method of 3-dimensional steering is proposed, which makes it possible to steer without using an additional pneumatic motor.

View full abstract

This paper proposes a new type of mobile method called Fluid Ropeway aiming to collect information in dangerous buildings as rapidly and safely as possible. The device to realize it is mainly composed of a flexible flat tube and a gondola probe, which is driven by fluid power using buckling phenomenon of the tube. The big advantage is the gondola has possibility of traversing rocky terrain where wheel types and crawler ones are hard to cross over, because it can go forward by the driving force not against the ground but against the tube.

View full abstract

This research consists of the development of a casting-type adhesive object to aid rescue operations inside dangerous buildings. In past research, an inspecting method called fluid ropeway is proposed. In order to move the inspector smoothly, it is necessary to fix the tube in a high position. Inspired in an octopus sucker, this adhesive object absorbs easily to the wall or ceiling by sticking, and a stable adhesive force is produced through application of negative pressure in the sealed space by the object. This composed of sticky elastomer in its outer surface, and in the inside there are small cylinders in order to create a negative pressure by suction of air and internal volume expansion. The experiments show the effectiveness of adhesion to the wall or ceiling using the casting device and also of inspection using fluid ropeway.

View full abstract

We have been proposing a gathering method for disaster area information by launching deployment of sensor node. The paper describes a mechanism controlling a cable length that unreels by launching of wired sensor node. The cable is wound on a reel that a powder brake and a rotary encoder are mounted on its rotation shaft. The cable length is measured by rotary encoder, and is adjusted by putting a break on the rotation shaft by the powder break. In the evaluation of the mechanism, we measured the length of cable connecting sensor node by free fall experiment. Then, an experiment confirmed that the proposed mechanism could control the length of a cable.

View full abstract

The authors have been developing an information-gathering system using mobile robots and WSNs (Wireless Sensor Networks) in underground spaces in post-disaster environments. In our system, mobile robots carry wireless sensor nodes (SN) and deploy them into the environment. This paper describes a design of deployment interval of SNs for WSN construction to improve fault tolerance of SNs. SNs are deployed to ensure communication performance of throughput for teleoperation of rescue robot via WSN in underground spaces. If some SNs are in failure, communication path is reconstructed to maintain end-to-end throughput of WSN. Experimental results using a proposed method are presented.

View full abstract

In Teleoperation, operator mainly control a robot based on images obtained from cameras mounted on the robot. Therefore, it is important to provide remote information in understandable shape for the users, if we consider efficiency and safety. We have been developing environmental awareness by using omni-directional camera. Since robot runs rough terrain, the images from the mounted camera are not stable. These unstable images will make the operator difficult to understand the surrounding information. In this paper, we propose Omni-directional image stabilization method to improve environmental awareness in Teleoperation.

View full abstract

Tracked vehicle with sub-tracks has high driving performance on rubble. However, navigator cannot observe position in contact with the rubble and crawler using camera and inertial sensor mounted on the tracked vehicle. Therefore, tracked vehicle was losing a balance on rubble and sub-tracks applied overload to motor when it stacked on rubble. In this paper, we propose the way to measure the force applied to the drive system at cannot mount contact sensor and the contact position cannot observe by camera using the dynamics of the robot and the inertial sensor information. By using the proposed method, we will be able to estimate the state of tracked vehicle that it stuck on the rubble and it run upon rubble and steps.

View full abstract

Several small subsurface explorers have been developed in order to reveal the origin of a planet and scientific investigation. These explorers couldn't excavate deep due to the effect of the earth's pressure for the wall holding downward movement. Hence we have developed a novel planetary subsurface explorer robot with propulsion and excavation units based on an actual earthworm. This paper first describes the movement of peristaltic crawling and the concept of our subsurface explorer robot. Next we develop a prototype of excavator with a propulsion unit based on peristaltic crawling and with an excavation mechanism based on an earth auger. Excavation experiments are successfully conducted using the excavator and at lighter weights. It is confirmed that the excavator can begin boring from a launcher, and in case of excavator of 1/6 of its own weight.

View full abstract

Methods of underground installation of some geophysical sensors such as seismometers and heat flow sensors are required for future lunar and planetary exploration. On the Moon, the installation below several tens centimeters makes these sensors able to survive during the night without any thermally shielded mechanism. On the other hand, methods of driving piles into the regolith would help robots to operate, because it is very difficult to obtain enough reaction force in the regolith which is powdery and soft. In 2008, we proposed a new mechanism we called "Self-Turning Screw Mechanism (STSM) which uses reactive torque of a wheel for drilling into the regolith. In this paper, we report the concept of the STSM, the design of our recent prototype and the result of experiment. The length, diameter, and weight of the prototype are 364.6mm, 80mm, and about 2.5kg respectively. In the latest test, the prototype could drill at a depth of 648mm into flyash sand which simulates the lunar regolith. This result proved applicability of the mechanism to autonomous drilling system in the future landing missions.

View full abstract

A screw locomotion principle is one of the potential methods for traveling on sandy terrain. Its interactive mechanics for surface locomotion, however, remains to be elucidated. This paper discusses interaction modeling between a helical screw propulsion unit and soil. The new interaction model is established based upon soil mechanics. The validity of the model is also evaluated by comparison of labotratory tests.

View full abstract

Supposing a space mission of setting monitoring devices at suitable positions on the moon, we discuss how to apply a casting manipulation to the mission. This paper addresses a mechanism of a casting manipulator system and control method to launch a penetrator to the desired position. First, we classify launching methods, and focus on a method by using rotation of a boom. We then propose the mechanism that keeps a posture of the penetrator equipped at the tip of the boom constant for the absolute coordinate system during its rotation. This mechanism prevents the wire which connects the penetrator and the robot's base from winding the boom. Analyzing a position error of landing point caused by delay of releasing the penetrator, we propose the motion control of the boom to reduce the error. Finally, we develop the system and verify the effectiveness of the proposed method.

View full abstract

The authors have developed a construction robot for retaining walls to protect a moon base from radioactive rays and heat. Our robot builds the walls in less material, by stacking sandbags which wrapped regolith in fiber sheet. A concept of this robot system is described in this paper. And the geometry of the lunar sandbag wall is designed based on the stability analysis of the wall and the static mechanics of the sandbag.

View full abstract

In future planetary exploration missions, planetary robots are required to traverse over very rough terrain. On the lunar surface and Mars surface, there are covered with loose soil. The mechanism, which occurs stacks, is not yet clear. Mobility performance of rover change by the wheel forms. However, the research is very few that focus on wheel forms. Therefore, this paper investigates the kinematics behavior of planetary rovers with loose soil traction mechanism from the standpoint that wheel forms about wheel size, wheel with or without lug. Wheel with lug increase mobility performance than without. Moreover, from running experiments when radius of the wheel becoming large, the mobility performance of wheel increases

View full abstract

Mobile robots play an important part in planetary or volcano exploration. However, their fields are covered with loose soil. Therefore, wheels of the robots may slip and, in the worst case scenario, they get stuck into the weak soil. To deal with this problem, spoked wheels that have long spokes radially may have a good performance to traverse on such loose soil. In this study, we developed a mobile robot with spoked wheels and conducted experiments using the robot with different spoke parameters in various environments. In this paper, we first explain the mobile robot with spoked wheels and the experiments using the robot. Furthermore, we introduce an improved version of the robot with spoked wheels on the basis of the evaluation in the experiments.

View full abstract

Lunar and planetary explorations have been increasingly planned across the world where mobility on the planetary/lunar surface is needed. In this paper we propose a new type of very small rover - typically with the weight of less than 2kg. Several new ideas are proposed: simplified locomotion mechanism with elastic wheels and passive suspension system for investigating a hole connected to a lunar lava tube. Moreover, we carried out the ruing experiment using loose soil with slope and step. From results, we conclude mobile about proposed mobile rovers.

View full abstract

Unmanned mobile robots for surface exploration of the moon have been extensively studied and developed. A lunar rover is expected to travel safely in wide area and explore in detail. This paper focuses on the rover mobility on such sandy terrain as lunar surface. This paper deals with dynamic sinkage of lunar rovers. Because of parameter of lunar surface is nonconstant, it is difficult to estimate dynamic sinkage by calculating. We need to get contacting angle between wheel and loose soil on line. Therefore, we develop a sensing wheel with tactile sensors that enable a getting contact angle and estimating dynamic sinkage. In this paper, we introduce the system of a sensing wheel and describe the conclusion using experimental results.

View full abstract

We developed a new type 3-wheeled lunar rover Tri-Star IV. This rover has two arms which rotate around horizontal axis and have a wheel with its end. With these arms, Tri-Star IV can expand from storage posture, return from stuck situation and adapt to a slope or rough terrain. We also developed a new wheel for the moon surface which is constructed with spring spoke and canvas. Through experiments, we confirmed the wheel's performance on the sand is greater than the normal wheel. In this paper, the new rover Tri-Star IV and wheel are explained and the field experiment at Nakatajima-sakyu on 9/3/2011 is reported.

View full abstract

This paper studies the use of ultra-sonic motors in application for lunar or planetary exploration. Space missions require a light and small actuator with low power consumption. Ultra-sonic motor is one of promising candidates for space use. Some space environment tests are conducted for investigating the performance of USM.

View full abstract

The mobile robot is using landmark its the position, in order to acquire the environmental data efficiently. To use landmark effevtively for other systems, it is important that robustness tracking of landmarks. However those system has much calculation cost and it cannot tracking after the frame out. In addition the case of initial landmark extraction, also the condition is necessary for choosing time cost and the object which is easy to tracking securely. In this paper,proposed landmark tracking method, which is using self position which estimated Visual Odometry, and auto extraction system of initial landmark.

View full abstract

An autonomous rover that is used as planetary exploration or rescue should work in unknown environment. Therefore, the rover needs to adapt to a new environment and should have to change its moving form. Therefore, a rover needs to judge situations around it, and should select the best action autonomously. This study aims at creating a rover which gets the best motion strategy for the environment or the action to recover from a stacked situation autonomously by using legs and wheels. For the adaptation method, we use a Reinforcement Learning scheme. To investigate availability of rover and to see the effect of learning, this study prepared virtual situations to escape from irregular ground as the experiments. As a result, the effectiveness of the method was shown. However, the result shows that the parameter largely effects over learning speed and the quality of solutions.

View full abstract

When the planetary exploration rover is operated actually, there are human errors and problems of communication time delay and measurement error. These problems debase efficiency of the remote control and safety of autonomous. So we have proposed tele-driving system with command path compensation algorithm. In this paper, Command Path Compensation algorithm is introduced, to clarify the issues for measurement error by simulation. To solve the issues, we proposed landmark measurement system applying Particle Filter, and we done implementation and measurement experiment. In addition, we compared conventional system with new system by simulation to verify the effectiveness of new system.

View full abstract

Space Elevator has been attracting attention as an alternative means of transport in rocket technology. In this study, we developed a prototype Space Elevator Climber, and compared the characteristics of single and multi-climber(consists of connected several actual climber). We also developed an indoor experimental system for Spase Elevator Climber to avoid the disturdance of wind,etc.

View full abstract

This paper describes motion analysis of a tethered pico-satellite. Its attitude and translation are controlled by a reaction wheel utilizing tether tension and by tether tension, respectively. A reaction wheel is actuated based on feedback information of angular velocity, and tether tension is controlled by torque transmission device. Especially, two tension control strategies were experimented. One is keeping constant tension, and the other is active tension control. The microgravity experiments by parabolic flight of an airplane were performed, in order to evaluate the controls. It is noted that attitude of the tethered body performed rotational vibration and it was damped by the reaction wheel control. Also, difference of keeping constant tension and active tension control was confirmed.

View full abstract

The number of pace debris in orbits keeps increasing year after year and it is becoming difficult to fly safely in space. In order to fly safely, it is inadequate to use ordinary techniques for reducing or defending space debris. In the near future, it is inevitably necessary to establish a systematic method of removing space debris. In this report we propose a new method of a removing system of space debris.

View full abstract

In order to develop space robotic technologies, the feasibility and reliability of space robot systems have to be verified by repetitive operation tests. However it is hard to verify that in orbit because of costs and safety. Hybrid motion simulation is one of the effective ways to simulate under micro-gravity condition on the earth. However, simulating a continuous contact such a capturing a floating object by a hybrid motion simulation, there is a problem that the kinetic energy of a target increases. This paper presents that the energy increase is caused by dead-band processing to force/torque data. Two compensation methods for dead band are proposed. And a single-axis collision experiments is carried out. The presented compensations successfully suppress the energy increase.

View full abstract

In orbital work like a capturing a target in space, a safety must be guaranteed at all times. In order to capture a target automatically, it is essential to figure out the behavior of target after contact. At first, we clarify the dangerous condition of contact by analyzing the behavior. The goal of this study is to propose the way of safe caputuring with consideration for the condition. This paper describes the capturing simulator for analyzing the behavior of target, especially the mission for capturing H-II Transfer Vehicle(HTV) by Space Station Remote Manipulator System(SSRMS).

View full abstract

A hybrid motion simulator which simulate orbital operations is known for a characteristic problem that the kinetic energy of the system increases during contact and collision because of delay times. To solve this problem, Osaki proposed a compensation of delay time that realizes a variable coefficient of restitution, and applied this compensation with translational motion of one axis. This paper verifies whether a compensation with translational motion and rotational motion of six axis is effective by experiments. Additionally, it proposes a method for improving accuracy of compensation. After that, experiments are conducted to evaluate the proposed compensation with the axis that has not acted effectively compensation.

View full abstract

The final goal of this study is to develop a buoyancy control device for underwater robot utilizing phase change of material. A conventional underwater robot and submarine adjust buoyancy by discarding a set of iron balls or seawater in other place, which is harmful to the environment. Therefore, we proposed new buoyancy control method utilizing phase change of material. In this paper, we report the improvement of the buoyancy control device that utilizes expansion and contraction of metal bellows, which we proposed in the previous paper. Paraffin wax filled in the device was cooled by peltier devices and heated by them and a nichrome wire, resulting in volume change. We designed a new device with a new mechanism to reduce the mass of the device and to improve the insulation characteristic and the heating speed of the device. As a result, the mass of the new device is two sevenths that of the previous one. Also we confirmed that the new device has high insulation characteristics compared with the previous one.

View full abstract

A fish-like aquatic robot, which has a smart-tailfin driven by electric-driven SMA-actuator, is introduced. The tailfin consists of a flexible polypropylene sheet with two fiber-like SMAs pasted on the both surface of the sheet. Control of a displacement of the fin is tried by measuring the change of the electric resistance of SMAs due to their deformation. Outlines of the structure and mechanism of the robot are introduced, and the experimental results by a prototype robot are shown.

View full abstract

In this study, we have developed a fish-like robot with elastic fin, which is actuated only a single actuator. Since an elastic fin appropriately bends due to the interaction to the surrounding fluid, the robot can swim smoothly even though it has only a single actuator. For higher swimming performance, we developed a fish-like robot which has half size compared with conventional one, and evaluate its swimming performance.

View full abstract

We have developed an attitude control system for a human-sized underwater robot with dual-arm, based on shifting the center of buoyancy with respect to the center of gravity. Shifting of the center of buoyancy is accomplished by two float blocks that are able to move independently. In this paper, we discuss an algorithm for calculating control inputs of positions of the moving floats.

View full abstract