Hidenori Ishihara

Micro resonator using electromagnetic actuator for tactile display

This paper proposes a tactile display for presenting the moving or the shearing direction to the skin of a human finger. We consider stimulating tactile sense by vibration and the development of a tactile feedback system. The proposed vibro-tactile stimulator employs a number of vibrating pins to provide a ticking sensation to the human operators skin. We used micro resonators driven by electromagnetic force to vibrating pins. We performed an experiment to present vibro-tactile stimulation using a single micro resonator, and confirmed the ability to perform vibro-tactile stimulation. Next we arrayed the micro resonators in a matrix state and constructed the tactile display. We made a tactile feedback experiment using this display. From the experimental results, it was made clear that the tactile display had the ability to present much information to a human finger.

Design and experimental evaluation of a teleoperated haptic robot–assisted catheter operating system

Minimally invasive surgery and therapy is popularly used both for diagnosis and for surgery. Teleoperation, a promising surgery, is used to protect the surgeon from X-ray radiation as well as to address the problem of lacking experienced surgeons in remote rural areas. However, surgery success ratio should be considered because the surgeon was separated from the patient remotely. A most effective addressing method to improve success ratio is design of a haptic interface as a master console, which can provide the “immersive” operation to the surgeon. In this study, a haptic catheter operation system for teleoperation through exploiting magnetorheological fluids is proposed to solve the safety problem. The haptic sensation is provided by varying the viscosity of the magnetorheological fluids by adjusting the magnetic field, which is dependent on the force measured in the slave manipulator. Therefore, three parts of the haptic interface were designed and fabricated: magnetic field, magnetorheological fluids container and haptic performance calibration mechanism. Some preliminary experiments have been done to verify the effectiveness of this kind of haptic interface. Experimental results illustrated that the designed haptic catheter operation system can be used for teleoperation and for training the surgeon for the non-experience.

Design and performance evaluation of an amphibious spherical robot

This paper presents an amphibious spherical robot that consists of a sealed upper hemispheroid, two quarter spherical shells, and a plastic circular plate. It has a plastic shelf for carrying the micro-robots, and four actuating units for movement. Each unit is composed of a water-jet propeller and two servomotors, each of which can rotate 90? in the horizontal and vertical directions. The robot is capable of motion on land, as well as underwater. The robot is capable of three walking gaits; therefore, we describe experiments on various terrains to evaluate the walking motion performance, including stability and velocity. Additionally, plenty of underwater experiments are conducted to evaluate the underwater performance, containing horizontal and vertical motions, and to verify the fixture and deployment mechanism for the micro-robot. We describe an amphibious spherical robot, which is capable of motion on land, as well as underwater.The amphibious robot has two actuation systems: a quadruped walking actuation system and a water-jet actuation system.The amphibious robot can move with a relatively high velocity and for a relatively long period of time on land and underwater.The amphibious robot can carry the micro-robot, which is used as a manipulator underwater.

Safety Operation Consciousness Realization of a MR Fluids-Based Novel Haptic Interface for Teleoperated Catheter Minimally Invasive Neurosurgery

In catheter minimally invasive neurosurgery (CMINS), catheter tip collision with the blood vessel detection during the surgery practice is important. Moreover, successful CMINS is dependent on the discrimination of collision by a skilled surgeon in direct operation. However, in the context of teleoperated scenario, the surgeon was physically separated. Therefore, the lack of haptic sensation is a major challenge for a telesurgery scenario. A human operator-centered haptic interface is adopted to address this problem. In this paper, a teleoperated robotic-assisted surgery and psychophysics-based safety operation consciousness theory was presented. Moreover, a human operator-centered haptic interface design concept is first introduced into actuator choice and design. A semiactive haptic interface was designed and fabricated through taking full advantage of MR fluids. Furthermore, a mechanical model (force/torque model) was established. In addition, in case of no collision, transparency of a teleoperated system was realized; in case of collision, psychophysics-based collision discrimination control scheme was first presented to provide safety operation consciousness. Experiments demonstrate the usability of the designed haptic interface and correctness of the safety operation consciousness control scheme.

Basic studies on wet adhesion system for wall climbing robots

This paper reports a vacuum-based wet adhesion system for wall climbing robots. In this adhesion system, a suction cup adheres on a wet surface. The problems addressed are an adherability on a rough surface, which is comes from the seal action of a liquid, and low friction between suction cup and adhered rough and smooth surfaces which is comes form lubricating action of a liquid. Generally, it is difficult that a vacuumed suction cup adheres on rough surface such concrete plate and hardly slidable. In this paper, the adhesion force and friction when a suction cup adheres on smooth glass plate and concrete plate are measured and compared wet condition with dry condition. The experiment result showed that a viscosity is important at the sealing performance of adhesion on rough surface. The silicon oil of a viscosity of 5000cSt allows a suction cup to adhere on concrete surface. In this condition it comes up to the adhesion force when a suction cup adheres on smooth glass with dry condition.

Mechanisms and basic properties of window cleaning robot

In this paper, we propose a lightweight small robot for window cleaning, which is developed for practical use in life environment. The moving mechanism is made up of 2 drive wheels and a suction cup, which are jointed around a shaft. By this mechanism the robot moves to any directions along the vertical window. First, we introduce the adsorption and locomotion mechanisms of window cleaning robot. Next, we show the design of First Prototype and then report the mobility of it. Then we analyze the adsorption and locomotion mechanisms and illustrate the design of Second Prototype based on these analyses.

Control of the distributed autonomous robotic system based on the biologically inspired immunological architecture

In this paper, we propose a new algorithm to control a distributed autonomous robotic system under dynamically changing environment based on immunological interaction between robots. Our algorithm can organize the robot population for dynamically changing multiple works. At first, we designed a control architecture for a multiple robotic system based on B-cell (which is main agent of immune system) interaction. Immune system has various kinds of B-cells, and B-cell interaction can organize its population balance against dynamically changing environment. We set the analogy between distributed autonomous robotic system and biological immune system. We verified the performance of our algorithm by computer simulation. As a simulation example there is considered the transportation of multiple objects to multiple locations against a deadline, with time-varying demand.

Comparison of sEMG-Based Feature Extraction and Motion Classification Methods for Upper-Limb Movement

The surface electromyography (sEMG) technique is proposed for muscle activation detection and intuitive control of prostheses or robot arms. Motion recognition is widely used to map sEMG signals to the target motions. One of the main factors preventing the implementation of this kind of method for real-time applications is the unsatisfactory motion recognition rate and time consumption. The purpose of this paper is to compare eight combinations of four feature extraction methods (Root Mean Square (RMS), Detrended Fluctuation Analysis (DFA), Weight Peaks (WP), and Muscular Model (MM)) and two classifiers (Neural Networks (NN) and Support Vector Machine (SVM)), for the task of mapping sEMG signals to eight upper-limb motions, to find out the relation between these methods and propose a proper combination to solve this issue. Seven subjects participated in the experiment and six muscles of the upper-limb were selected to record sEMG signals. The experimental results showed that NN classifier obtained the highest recognition accuracy rate (88.7%) during the training process while SVM performed better in real-time experiments (85.9%). For time consumption, SVM took less time than NN during the training process but needed more time for real-time computation. Among the four feature extraction methods, WP had the highest recognition rate for the training process (97.7%) while MM performed the best during real-time tests (94.3%). The combination of MM and NN is recommended for strict real-time applications while a combination of MM and SVM will be more suitable when time consumption is not a key requirement.

Design of a Novel Telerehabilitation System with a Force-Sensing Mechanism

Many stroke patients are expected to rehabilitate at home, which limits their access to proper rehabilitation equipment, treatment, or assessment by therapists. We have developed a novel telerehabilitation system that incorporates a human-upper-limb-like device and an exoskeleton device. The system is designed to provide the feeling of real therapist–patient contact via telerehabilitation. We applied the principle of a series elastic actuator to both the master and slave devices. On the master side, the therapist can operate the device in a rehabilitation center. When performing passive training, the master device can detect the therapist’s motion while controlling the deflection of elastic elements to near-zero, and the patient can receive the motion via the exoskeleton device. When performing active training, the design of the force-sensing mechanism in the master device can detect the assisting force added by the therapist. The force-sensing mechanism also allows force detection with an angle sensor. Patients’ safety is guaranteed by monitoring the motor’s current from the exoskeleton device. To compensate for any possible time delay or data loss, a torque-limiter mechanism was also designed in the exoskeleton device for patients’ safety. Finally, we successfully performed a system performance test for passive training with transmission control protocol/internet protocol communication.

New PZT actuator using piezoelectric thin film on parallel plate structure

The parallel beam structure and the hydrothermal method have many significant features. Combining these features, we made a PZT microactuator by the hydrothermal method on the parallel beam structure. The basic properties of the prototype are investigated. We propose applications of this actuator: the multi degrees of freedom actuator, G-sensor, and vibration gyroscope. Finally, we measured the relationship between output-voltage and rotation.