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Birds are agile in locomotion and able to move quickly and easily from one place to another. When a bird is on the ground, and a threat approaches, the bird will fly away and escape. An ornithopter robot provides advantages in energy saving, maneuverability, and crash safety. Most flapping robots require an operator or assistance to take off. The goal of this study is to enable self-takeoff from the ground. The developed robot can generate thrust to its body by exceeding its own weight using a simple flapping mechanism and lightweight design. The result of the takeoff experiment showed that the ornithopter robot was able to self-takeoff from the ground without assistance.

In recent years, force display systems that supports rehabilitation of paralyzed patients have been developed and the effectiveness has been clarified. Force displays are classified into passive type and active type. A passive-type system using brakes has less risk of harming a user compared with an active-type system using motors. Therefore, passivetype system is safe and low cost, and can be used at home. In this paper, we develop a planar 2-DOF passive-type force display system with redundant powder brakes whose characteristics are experimentally obtained. Four configurations of brakes are illustrated. The tracing experiments are conducted to clarify the difference of haptic performance of them.

In recent years, it becomes popular to use robots that clean houses. In the future, it is expected that various robots having arm are used at home. But the robot arms used in factories are large and heavy, so it is difficult to use them at home. In this study, an expansion and contraction mechanism, which has a capability of portability and easiness of put-away, have been proposed and the robot arm have been developed using it. The previous robot arm was manually expanded and contracted. In this paper, we improved the robot arm so that can automatically expand and contract and have a wide movable range.

This paper presents the novel capabilities of a quadruped robot by performing horizontal-vertical-horizontal movement transition through vertical ladder without handrailing supporter. To overcome the proposed problem, we propose a multi-behavior generation model using independent stepping and pose control in the quadruped robot. The model is able to generate appropriate behavior depending on external (3D point clouds) and internal sensors (ground touch sensor, and Inertial Measurement Unit). Posture condition, safe movement area, possible touchpoint, grasping possibility, and target movement are the information that is analyzed from the sensors. There are four options developed in behavior generation, which are, Approaching, Body Placing, Stepping, and Grasping behavior. In order to prove the effectiveness of the proposed algorithm, the model was implemented on the computer simulation and the real application. Before being applied in the real robot, the proposed model is optimized in the computer simulation. Then, the optimized parameter is used for applying in the real robot. As a result, the robot succeeded to move through the ladder without handrail from lower stair to upper stair. From the analysis, the body placing behavior is the most important strategy in the proposed case.

Most robots involved in vertical movement against gravitation require actuators large enough to support their own weight. To improve the inherent safety of such robots against the large actuators and reduce their energy consumption, numerous gravity compensation mechanisms (GCMs) have been proposed. Our previous study proposed a variable GCM (VGCM) that uses two types of springs and can adjust the compensation force. In this paper, a VGCM-based scissor lift (pantograph lift) that uses three springs and a smaller actuator is proposed. A prototype is designed and fabricated, and the performance of the prototype is evaluated experimentally. The results demonstrate that the developed scissor lift meets the design specifications. In addition, a load estimator is established based on the dynamic model of the scissor lift. A real-time self-adjustment method that automatically changes the compensation force is proposed, and its effectiveness is verified.

This chapter introduces a novel four-limbed robot, WAREC-1, that has advanced locomotion and manipulation capability with versatile locomotion styles. At disaster sites, there are various types of environments through which a robot must traverse, such as rough terrain filled with rubbles, narrow places, stairs, and vertical ladders. WAREC-1 moves in hazardous environments by transitioning among various locomotion styles, such as bipedal/quadrupedal walking, crawling, and ladder climbing. WAREC-1 has identically structured limbs with 28 degrees of freedom (DoF) in total with 7-DoFs in each limb. The robot is 1,690 mm tall when standing on two limbs, and weighs 155 kg. We developed three types of actuator units with hollow structures to pass the wiring inside the joints of WAREC-1, which enables the robot to move on rubble piles by creeping on its stomach. Main contributions of our research are following five topics: (1) Development of a four-limbed robot, WAREC-1. (2) Simultaneous localization and mapping (SLAM) using laser range sensor array. (3) Teleoperation system using past image records to generate a third-person view. (4) High-power and low-energy hand. (5) Lightweight master system for telemanipulation and an assist control system for improving the maneuverability of master-slave systems.

PurposeUnderwater robots are one of the effective solutions for underwater exploration. Fish's swimming motion is more effective and efficient than propeller screw propulsion which is more popular for underwater vehicles. So far, a lot of fish‐like robots that have several actuated joints have been developed. They realize arbitrary motion by controlling the joint angles simultaneously. On the other hand, using an elastic fin may reduce the number of actuated joints and the total energy consumption. The purpose of this paper is to develop a fish‐like robot driven by a single actuator with an elastic tail fin.Design/methodology/approachSince an elastic plate appropriately bends due to the interaction to the surrounding fluid, a robot with the elastic fin can swim smoothly even though it has only a single actuated joint. However, in order to improve the swimming performances, it is required to optimize the shape of fin (width, thickness, distribution, etc.). Although computational fluid dynamics technique is one of the methods to assess the effectiveness of a certain shape of fin, it may take longer to obtain the results. Therefore, in this study, a simplified simulator is constructed and a better shape of fin is explored.FindingsFour types of fin shape were prepared and the swimming experiments were conducted. The swimming velocity changed according to the frequency and the shape of fin. In order to find the optimal shape of fin, the simulator of five‐link model surrounded by fluid is constructed. The differences of velocity can be found according to the parameters of fin shape. The simulation showed the similar trend as the experiments although the absolute values of velocity did not correspond. It is thought that the developed simulator can estimate the relative performance of fins.Originality/valueMost fish robots that have been developed so far consist of rigid links and multi‐actuated joints, which can realize arbitrary motion by controlling the joint angles simultaneously. On the other hand, using an elastic plate as a tail fin may reduce the number of actuated joints and the total energy consumption although it is not easy to realize arbitrary attitude. In this paper, a fish‐like robot driven by a single actuator with an elastic tail fin was developed. This technique makes the mechanism of a fish‐like robot simple.

Traditionally, robots and humans work independently, isolated from each other for safety reasons. We developed a robot for use on the assembly line which works together with a human operator, assisting and augmenting the operator's skills. Because of its function, this robot is known as the “Car Window Installation Assist Robot” and is currently in use on the plant of Toyota Motor Corporation. In this paper, we propose a method to estimate human intent as well as a skill assist control method. Moreover, we present technology that enables safe human-robot cooperation, high product quality, and the cycle time of only 48 seconds.

Industrial robots have been widely used in factory automation. On the other hand, in the final assembly in automobile factories, many tasks are still completed by humans due to the difficulties and costs associated with automation. One example still requiring skilled human operators is the installation of the automobile window. The window installation assist robot we developed enables a single operator to install a window easily. The present study focuses on kinesthetic assistance including preliminary experiments and application to automobile window installation during car assembly demonstrating the effectiveness of our proposal.

This paper is concerned about a variable impedance control for human-machine cooperative positioning systems. The prospective profile is found from the dynamic equation and the properties of the operational profiles known as suitable ones. We propose a simple variable impedance control in which the damping coefficient is varied according to the operational force of human based on the above profile. The experiments of positioning tasks are examined and the effectiveness of the proposed method is shown. The properties on conventional methods are compared.

An isokinetic exercise is one of the training methods. Servomechanism using electric motor has been used for isoki netic exercise system. But, isokinetic exercises can be realized by using passive devices such as brakes or dampers. Since such passive systems are inherently safe, they are suitable for mechanical systems which are operated by hu man beings. In this study, we develop the brake using particle-type ER fluid. ER fluid is a fluid whose rheological characteristics can be controlled by electric field. ER brakes can response very quickly and have the characteristics like Coulomb friction. Then, we discuss the velocity control of ER brake system. Finally we confirmed the validity of the proposed method by control experiments.

We propose a robot arm using ultrasonic motors and demonstrate its characteristics such as high responsiveness and backdrivability, which are important characteristics in the view of the safety. The high responsiveness allows the robots to avoid collision against any objects and backdrivability makes the robots have compliance to unexpected actions of people. In this paper, we clarify the responsiveness and backdrivability of the ultrasonic motors experimentally. For the demonstration, we build a prototype robot arm having three joints which are all directly coupled to the output axis of the ultrasonic motors. In the experiments, the robot showed the responsiveness less than a few milliseconds, torque control such as if torsion spring model, and the backdrivability as a free joint. We discuss the safety control strategy using these characteristics‥

We have developed the robotic vehicle on water that moves by the rider's balance. Previously, due to the lack of stability of the vehicle, balancing skill was required for the rider. In general, the center of buoyancy of the floating body influences on the stability. Therefore, in this paper, the floating vehicle was modeled and the appropriate body shape and size that improves the stability was simulated. We developed the novel vehicle on water named MINAMO (Multidirectional INtuitive Aquatic MObility), which realized higher stability. In addition, in order to improve the maneuverability for the rider, a force plate is introduced as an interface and MINAMO realized the straight and whirl movement by the control of the rider weight shifting.

The development and simulation of robots that have athletic skill close to human beings is very much useful for testing and developing sport goods. This paper discusses the development and simulation of a tennis robot. The developed tennis robot has two joints controlled by a servolike human muscle, and its characteristics are satisfying and similar to a human. The simulation for the whole system including racket, ball and tennis robot is set up. The simulation results agree well with experimental results.

Semi-closed-loop control of a robot achieves only the control of the angular position of the motor, so it is not clear whether the end-effector is precisely positioned or not. Closed-loop control would improve positioning accuracy, but industrial robots which have elasticity in their driving systems might become unstable easily because of the noncollocated positional relationship between sensors and actuators. This study, which is aimed at realizing high-speed and high-precision closed-loop control, uses an intelligent electrorheological fluid (ER fluid). In the next section, a brief introduction is given with respect to two types of ER fluids and the development of ER dampers. Following this is a description of the experimental apparatus, which consists of an ER damper and a one-link robot arm. A discussion of its mathematical model follows. In addition, the effects of an ER damper to the resonance/antiresonance characteristics of 2-inertia systems are discussed. Next, the design of the hierarchical control system is discussed. Firstly, the design of the inner loop controller for motor velocity control is presented. As an outer loop controller, an H/sup /spl infin// controller is obtained by using a mixed sensitivity design method of robust control theory. Then it is shown that the ER damper makes the design of a high gain controller possible while maintaining robust stability. Finally, the effectiveness of the proposed control method is demonstrated by experiments.

PurposeA lot of unique transportation devices on the ground have been developed. On the other hand, on water, there are a few personal devices, which sometimes need paddling to get around. If the personal mobility that make it possible to move intuitively and quickly on water is realized, it will be useful for survey of rivers and ponds, rescue, amusement and so on. Therefore, in this study, an omnidirectional vehicle on water (O‐VOW) is proposed which is controlled according to information of the inclination based on a rider's balance.Design/methodology/approachA prototype of O‐VOW consists of a boarding part, three thrusters and a control unit. The control unit includes a three‐axes accelerometer, a microcomputer and batteries. The inclination of O‐VOW is calculated from the information given by the accelerometer. The control rule for O‐VOW is described in matrix form and is implemented into the microcomputer. The microcomputer commands three thrusters according to the inclination. The preliminary and riding tests are conducted on water.FindingsThe authors have developed a prototype of O‐VOW whose propulsion is controlled according to the inclination. The control scheme for O‐VOW was described in matrix form. The preliminary and riding tests are conducted on water and the effectiveness of O‐VOW was experimentally shown. O‐VOW can run, stop and adjust the course in all directions on water by the rider's balance.Originality/valueIn this paper, a novel transportation system that uses intuitive control on water has been developed. Since it moves in all directions, the rider can operate it even at a narrow channel without turning. It will assist in human activities such as survey, rescue, amusement in rivers, lakes, swimming pools and at sea.

In these days, patients and doctors in operation room are surrounded by many medical devices as resulting from recent advancement of medical technology. However, these cutting-edge medical devices are working independently and not collaborating with each other, even though the collaborations between these devices such as navigation systems and medical imaging devices are becoming very important for accomplishing complex surgical tasks (such as a tumor removal procedure while checking the tumor location in neurosurgery). On the other hand, several surgical robots have been commercialized, and are becoming common. However, these surgical robots are not open for collaborations with external medical devices in these days. A cutting-edge "intelligent surgical robot" will be possible in collaborating with surgical robots, various kinds of sensors, navigation system and so on. On the other hand, most of the academic software developments for surgical robots are "home-made" in their research institutions and not open to the public. Therefore, open source control software for surgical robots can be beneficial in this field. From these perspectives, we developed Open Core Control software for surgical robots to overcome these challenges.In general, control softwares have hardware dependencies based on actuators, sensors and various kinds of internal devices. Therefore, these control softwares cannot be used on different types of robots without modifications. However, the structure of the Open Core Control software can be reused for various types of robots by abstracting hardware dependent parts. In addition, network connectivity is crucial for collaboration between advanced medical devices. The OpenIGTLink is adopted in Interface class which plays a role to communicate with external medical devices. At the same time, it is essential to maintain the stable operation within the asynchronous data transactions through network. In the Open Core Control software, several techniques for this purpose were introduced. Virtual fixture is well known technique as a "force guide" for supporting operators to perform precise manipulation by using a master-slave robot. The virtual fixture for precise and safety surgery was implemented on the system to demonstrate an idea of high-level collaboration between a surgical robot and a navigation system. The extension of virtual fixture is not a part of the Open Core Control system, however, the function such as virtual fixture cannot be realized without a tight collaboration between cutting-edge medical devices. By using the virtual fixture, operators can pre-define an accessible area on the navigation system, and the area information can be transferred to the robot. In this manner, the surgical console generates the reflection force when the operator tries to get out from the pre-defined accessible area during surgery.The Open Core Control software was implemented on a surgical master-slave robot and stable operation was observed in a motion test. The tip of the surgical robot was displayed on a navigation system by connecting the surgical robot with a 3D position sensor through the OpenIGTLink. The accessible area was pre-defined before the operation, and the virtual fixture was displayed as a "force guide" on the surgical console. In addition, the system showed stable performance in a duration test with network disturbance.In this paper, a design of the Open Core Control software for surgical robots and the implementation of virtual fixture were described. The Open Core Control software was implemented on a surgical robot system and showed stable performance in high-level collaboration works. The Open Core Control software is developed to be a widely used platform of surgical robots. Safety issues are essential for control software of these complex medical devices. It is important to follow the global specifications such as a FDA requirement "General Principles of Software Validation" or IEC62304. For following these regulations, it is important to develop a self-test environment. Therefore, a test environment is now under development to test various interference in operation room such as a noise of electric knife by considering safety and test environment regulations such as ISO13849 and IEC60508. The Open Core Control software is currently being developed software in open-source manner and available on the Internet. A communization of software interface is becoming a major trend in this field. Based on this perspective, the Open Core Control software can be expected to bring contributions in this field.

This paper presents an approach for producing virtual fixture based on simulated plasticity, which can be used for assisting precise manual manipulations performed by human users through haptic interfaces. The fixture acts as a guide to help path-tracing tasks and as a wall for preventing a tool from entering a specified region, but the user can move against the fixture by intentionally producing a force larger than a predetermined yield force. The advantage of the proposed virtual fixture is that it is always passive and it acts as a hard fixture when the user's force is smaller than the yield force. The algorithm was demonstrated through experiments using an impedance-type haptic interface.

Human-machine cooperative systems have been proposed. Most of them consider carrying, positioning and assembling tasks. Precise tracking tasks are also required in factories. However, an assist system for tracking task has not been studied well. In this paper, we aim to realize the human-machine system that assists a tracking task. In order to achieve the goal, the virtual friction field is proposed. Isotropic and anisotropic friction fields are presented and they are applied to the rotating object which should be tracked. The tracking task experiments are carried out and it is shown that the virtual guide of the friction improves the tracking performance effectively.

Force information is often required for tele-operation systems and virtual reality. Conventional force displays are active systems with actuators. This, however, is inherently active, so that it may become a danger. Consequently, passive force display is an effective method for assuring safety. The authors developed a brake using ER (electrorheological) fluid and passive force display using ER brakes. They discuss two degree of freedom passive force display and basic control experiments.