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ABSTRACT: In this paper, we propose a novel closed loop elastic structure which can generate snap-through buckling with bending and distortion. The proposed mechanical closed loop structure consists of two rotary shafts and a belt-shaped elastic material which two ends are connected to one active rotary shaft and one free joint type shaft, respectively. Driving the active rotary shaft continuously, we can obtain impulsive motion by using snap-through buckling repeatedly. The change of the driving torque and the angular momentum generated snap-through buckling are shown by numerical simulations. From these results, it is shown that an offset parameter of the proposed structure is useful for generating impulsive turning motions of the compact swimming robot. The proposed mechanism is applied to a compact swimming robot which can turn impulsively at a maximum rate of 135 deg/s underwater.
Robotics and Automation (ICRA), 2011 IEEE International Conference on; 06/2011
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ABSTRACT: In this video, we propose the robotic jerboa which is a compact bipedal kick-and-slide robot powered by unidirectional impulse force generators. The robotic jerboa moves fast not only running forward but also turning right and left by kicking and sliding on the ground repeatedly. The robotic jerboa kicks toward the direction which the horizontal component is large by its legs in order to jump forward effectively. The robotic jerboa is composed as its legs are protruded out of the side of its body respectively for realization of the quick turning. We show that the palm-top size robotic jerboa whose weight is of only 70[g] achieves the velocity of 1.5[m/s] and the turning angular velocity of 11.5[rad/s] instantaneously.
Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on; 11/2010
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ABSTRACT: In this paper, we propose a robotic catapult based on closed elastica utilizing bending and twisting deformation of an elastic strip. By using snap-through buckling generated from not only bend but also twist of thin rectangle elastic strip, impulsive forces can be generated repeatedly by the frequency of 3[Hz] without changing added torque directions. The compact jumping robot based on the proposed robotic catapult can leap over 950[mm] away. In addition, by setting the parameters appropriately to make the best use of generating impulsive forces with high frequency, it can perform repeated low-altitude jumping motions with about 1.06[m/s] velocity including quick step of about 0.152[s].
Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on; 11/2010
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ABSTRACT: In this paper, we propose a compact kick-and-bounce mobile robot powered by unidirectional impulse force generators. The unidirectional impulse force generator is a simple mechanical device for generating high-frequency impulse forces toward a certain direction unilaterally utilizing snap-through bucklings. The proposed kick-and-bounce robot has a pair of the unidirectional impulse force generators as the muscles of its biped legs. The robot moves forward rapidly by the repetition of the kicks and bounces to the ground. We show that the developed palm-top mobile robot whose weight is of only 67 [g] achieves the velocity of 0.8 [m/s] instantaneously.
Intelligent Robots and Systems, 2009. IROS 2009. IEEE/RSJ International Conference on; 11/2009
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ABSTRACT: In this paper, in order to provide with an inexpensive solution to efficient bio-manipulation under microscope, we propose a macro-micro tele-operation system based on body image embedding. It is known in neuroscience that we could feel our body image for the object which is not our own body in certain conditions. Our idea is to utilize the body image illusion for generating high immersive feelings in bio-manipulation under microscope, instead of aiming at the perfect transparency, the conventional target of tele-manipulation system, which is difficult to attain. Our proposed system has two additional components as well as the conventional system where micro manipulators hydraulically connected to joysticks or dials handled by an operator are used for fine bio-manipulation under a microscope. The one component is for the body position/orientation consistency between proprioception and vision. In this component, due to appropriate use of a camera for a microscope, a visual display, mirrors and tiny dummy hands, an operator can see the magnified visual image of the tiny dummy hands similar to his/her own hands in shape at the position and orientation where he/she feel them proprioceptively. The other component is for the contact consistency between touch and vision. In this component, the contact between a tool grasped by an operator's hands and a manipulated object observed by eyes should coincide to the contact felt by his/her hand skin. To do this, haptic stimulators such as piezo actuators are activated at the timing of contact which is detected, for example, by the vision processing from the microscopic images.
Micro-NanoMechatronics and Human Science, 2008. MHS 2008. International Symposium on; 12/2008
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ABSTRACT: In this paper, we propose a new robotic catapult with a high stiffness endpoint. The conventional robotic catapults based on the closed elastica are robotic elements for generating impulsive motions by utilizing the snap-through buckling. In a typical robotic catapult, the two ends of an elastic strip are fixed to a free joint and an active joint, respectively. Here we found that by adding only the high stiffness at the free joint, compared to the conventional type, more elastic energy can be stored and release surely without loss of a characteristic of generating impulsive motion repeatedly. By utilizing the high stiffness endpoint, we develop a faster impulsive swimming robot than the conventional one.
Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on; 10/2008
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ABSTRACT: In this paper, we propose a new asymmetric robotic catapult based on the closed elastica. The conventional robotic catapults based on the closed elastica which the authors developed are the robotic elements for generating impulsive motions by utilizing a snap-through buckling. In a typical closed elastica, the two ends of an elastic strip are fixed to a passive rotational joint and an active rotational joint, respectively. Here we found that by adding only a range limitation to the passive rotational joint, compared to the conventional type, the deforming shape of the elastic strip becomes more complicated and 40% more elastic energy can be stored. Using this modification, we can develop a compact jumping robot which is able to leap over 700[mm] away and 200[mm] high.
Robotics and Automation, 2008. ICRA 2008. IEEE International Conference on; 06/2008
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ABSTRACT: In this paper, we propose jumping robots catapulted by the closed elastica which the authors developed as a robotic element for generating impulsive motions by utilizing the snap-through buckling. We show that one of our robots, which is about the size of 170 x 90 x 50 [mm], leaps 700[mm] away and 200[mm] high. We also show a legged jumping robot which pushes the ground impulsively by its leg attached to the closed elastica.
Micro-NanoMechatronics and Human Science, 2007. MHS '07. International Symposium on; 12/2007
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ABSTRACT: Two types of robotic catapults based on the closed elastica are proposed as robotic elements for generating impulsive motions. To obtain impulsive motions, these catapults utilize the snap-through buckling of an elastic material induced by applying driving torques to the ends of the elastic strip. In this paper, we show the effectiveness of the various types of the robotic catapults based on the kinematics and statics of a serial- chain approximation model. The numerical simulations show that these catapults can increase the elastic energy necessary for impulsive motions even if the driving torques decrease.
Intelligent Robots and Systems, 2007. IROS 2007. IEEE/RSJ International Conference on; 12/2007
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ABSTRACT: In this paper, we propose the impact manipulation of a string-like hyper-flexible robot where an impact force is applied to a given target point. The proposed impact manipulation law consists of three phases; the feedforward and feedback swing phases, and the positioning phase, based on the information on the estimated angular velocity at the connecting point between the hyper-flexible body and the actuator. First, in the feedforward swing phase, we apply sinusoidal horizontal motion generated by a linear actuator to one end of the manipulator. Next, we switch to the feedback swing phase where the estimated angular velocity at the connecting point between the hyper-flexible body and the actuator is utilized to obtain stably large swing motion of the manipulator. Finally, in the positioning phase, we bring the actuator to the target position after waiting for the timing judged from the angular velocity information so as not to damp the obtained large swing until the impact. Experimental results are shown to verify the effectiveness of the proposed impact manipulation law.
Advanced intelligent mechatronics, 2007 ieee/asme international conference on; 10/2007
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ABSTRACT: Modeling of friction force is cumbersome because of its discontinuity at zero velocity. This paper presents a set of discrete-time friction models for the purpose of haptic rendering and virtual environment construction. These models allow friction to be treated as an admittance-type or impedance-type element of a virtual environment. They are derived from implicit Euler integration of Coulomb-like discontinuous friction and linear mass-spring-damper dynamics, and have closed-form expressions. They include rate-dependent friction laws, and their extension to multidimensional cases is easy in most practical cases. The validity of the models is demonstrated through numerical examples and implementation experiments
IEEE Transactions on Robotics 01/2007; · 2.54 Impact Factor
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ABSTRACT: Here we show a tactile sensing for human-centered robotics. One is a multi-fingered hand system for telepresence based on the tactile information. The soft finger with the built-in compact tactile sensor is discussed from a biomimetic viewpoint. Another is a tactile enhancing tool that operates not only as a disturbance filter, but also, supposedly, as a magnifier of surface undulation. A simple physics is utilized to generate the enhancing effect.
Sensors, 2006. 5th IEEE Conference on; 11/2006
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H. Mochiyama
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ABSTRACT: In this paper, the theoretical foundation of robotic systems with hyper-flexible bodies with one-dimensional topological structure such as hyper-flexible manipulators is provided. Based on the rigorous kinematics and dynamics of hyper-flexible bodies, we can find the essential knowledge on the system.
Micro-NanoMechatronics and Human Science, 2005 IEEE International Symposium on; 12/2005
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ABSTRACT: 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.
Intelligent Robots and Systems, 2005. (IROS 2005). 2005 IEEE/RSJ International Conference on; 09/2005
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ABSTRACT: Friction force is cumbersome in numerical simulations due to its discontinuity at zero velocity. Fixed-step simulation techniques are especially desirable for control purposes, such as haptic friction rendering and friction compensation. Previous techniques have difficulties especially in numerical robustness and extensibility to multidimensional cases. This paper proposes two discrete-time friction models that can be used in fixed-step simulations. They can be used in multidimensional space, and can capture arbitrary velocity-dependent friction phenomena. The first one is a discrete-time discontinuous model. This model determines the friction force so that the velocity reaches zero in finite time by using the values of the mass and the timestep size. The second one is a discrete-time continuous model, which is a serial coupling of the discontinuous model and a linear viscoelastic element. This model is useful for haptic rendering because it is formulated as a velocity-input, force-output system. The second model can be extended into a more sophisticated friction model, which exhibits a hysteresis behavior in the presliding regime. Results of numerical simulations and an experiment are presented.
Intelligent Robots and Systems, 2005. (IROS 2005). 2005 IEEE/RSJ International Conference on; 09/2005
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ABSTRACT: In this paper, we provide a perspective of touch technology. Two illustrative examples are shown here to explain the potential of touch technology. One is TouchLens, a new type of haptic devices different from tactile sensors and displays. Through this haptic device by our hand we can perceive geometric information of tiny bumps and holes that are difficult to be detected by our bare hand. TouchLens is not only useful for inspections in manufacturing but also attractive as a fun haptic tool by which everyone can understand the power of haptic technology easily. The other relates to a haptic illusion called the velvet hand illusion in which we can feel an illusory surface with strange velvety, slippery or oily texture when we lightly rub a wire mesh of hexagonal pattern between our hands, keeping our hands pressed gently together. We found that moving line stimuli were also effective for eliciting the velvet hand illusion. The observed illusory phenomena caused by a variety of moving line stimuli allow us to see the underlying mechanism of human tactile information processing. Because the obtained illusory sensation is very impressive, it is expected that the illusion can be utilized as a main effect of a new type of haptic display.
Advanced Robotics and its Social Impacts, 2005. IEEE Workshop on; 07/2005
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ABSTRACT: In this paper, we report some observations related to a haptic illusion called the velvet hand illusion (VHI) in which we can feel a strange velvety sensation when we lightly rub a wire mesh of hexagonal pattern between our hands, keeping our hands pressed gently together. Moving line stimuli are used to find the conditions for eliciting the illusion in order to understand its mechanism deeply.
Eurohaptics Conference, 2005 and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2005. World Haptics 2005. First Joint; 04/2005
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ABSTRACT: Here we show a touch-enhancing tool that operates not only as a disturbance filter, but also, supposedly, as a magnifier of surface undulation. This tool, which we named "TouchLens," is composed of a sheet and numerous pins regularly arranged on one side of the sheet, having no electronic or mechatronic components. The most promising application of TouchLens is its use in inspection of sheet metals to detect small deflection defects and skill transfer in automobile industry.
Robotics and Automation, 2004. TExCRA '04. First IEEE Technical Exhibition Based Conference on; 12/2004
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ABSTRACT: This paper introduces a device for enhancing tactile perception of surface undulation. This device, which we call a "tactile contact lens," is composed of a sheet and numerous pins arranged on one side of the sheet. Our experimental results show that a small bump on a surface can be detected more accurately through this device than by bare finger and than through a flat sheet. A mathematical analysis of this phenomenon suggests two causes of this phenomenon. One cause is a lever-like behavior of the pins, which converts the local inclination of the object surface into the tangential displacement on the skin surface. The second cause is the spatial aliasing effect resulting from the discrete contact, by which the temporal change in the skin surface displacement is efficiently transduced into the temporal change in the skin tissue strain. The result of the analysis is discussed in relation to other sensitivity-enhancing materials, tactile sensing mechanisms, and tactile/haptic display devices.
Sensors, 2004. Proceedings of IEEE; 11/2004
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ABSTRACT: This paper proposes a sensor mechanism that detects temporal changes in shear strain. It is composed of a deformable capsule, viscous fluid filled in the capsule, single or multiple cantilevers projecting into the capsule, and strain gage(s) attached to the cantilever(s). When the capsule is being deformed, the cantilever receives bending force from the fluid. The mechanical adaptation function prevents mechanical damage to the strain gages and the saturation of the signal. We intend to use this sensor for a sheet metal inspection process in the automobile industry to detect surface deflection defects on the metal surfaces.
Sensors, 2004. Proceedings of IEEE; 11/2004
