Naoaki Tsuda

Bilateral Macro–Micro Teleoperation Using Magnetic Levitation

This paper introduces a novel magnetic-haptic micromanipulation platform with promising potential for extensive biological and biomedical applications. The platform has three basic subsystems: a magnetic untethered microrobotic system, a haptic device, and a scaled bilateral teleoperation system. A mathematical force model of the magnetic propulsion mechanism is developed, and used to design PID controllers for magnetic actuation mechanism. A gain-switching position-position teleoperation scheme is employed for this haptic application. In experimental verifications, a human operator controls the motion of the microrobot via a master manipulator for dexterous micromanipulation tasks. The operator can feel force during microdomain tasks if the microrobot encounters a stiff environment. The effect of hard contact is fed back to the operators hand in a 20 mm × 20 mm × 30 mm working envelope of the proposed platform. Conducting several experiments under different conditions, rms of position tracking errors varied from 20 to 40 μm.

Instruction of arm motion for calligraphy using vibrotactile stimulations

Traditional craftsmanship should be handed on to the next generation. Introduction of mechatronics technologies has potential abilities for recording and replaying such craftsmanship. Up to now, there have been some trials to conserve the traditional craftsmanship. However, most of these trials have been aimed for only conservation. In this paper, the way of using brush in calligraphy is focused on as an example of traditional craftsmanship that requires proper motor skills. The authors proposed a method to instruct a masters calligraphic skill to an apprentice using vibrotactile stimulations. Four vibratory motors are attached on the surface of the apprentices hand, and these motors give vibrotactile feedback to the apprentice for correcting his/her inadequate motions. Here, it is expected that the vibratory motors work as an effective device for arm motion guidance. The apprentice moves the arm in the direction of an activated vibratory motor. In a pilot experiment with several subjects, the applicability of using vibrotactile stimulation was confirmed. In the following experiment, instructions of writing three kind of character were achieved by controlling the vibratory motors properly.

Visualization system of crutch walking based on internal sensors

Crutches are often used for rehabilitation of the injured. For safety of patients, it is important to measure and analyze how patients walk with crutches, and to instruct them in the early stage is necessary. Measurement of motion of a crutch usually requires several external sensors, for example a motion capturing system which consists of several cameras and a computer. This takes a great deal of effort. Therefore, the authors developed a system which measures the angle of a crutch and the angular velocity of a crutch. Based on these sensors, the motion of a crutch can be estimated without external sensors. Through experiment, the authors have confirmed that the developed system can estimate and visualize the motion of a crutch based on only internal sensors embedded in the crutch.

Motion simulator for a multi-degree-of-freedom magnetically levitated robot

Magnetically levitated robots can move without lubrication, they generally have advantages to the use in the various special environments such as in a dust-free room, in a vacuum, in a flammable atmosphere, and in vivo. Meanwhile, they have a disadvantage of small working volume corresponding to the allowable air gap between the levitated object and the electromagnets. In some cases, to construct a combination of a magnetically levitated robot and an external manipulation device which has a comparatively large working volume seems an effective way to expand the whole working volume. On that premise, we are developing an experimental system for collaborative work between a multi-degree-of-freedom (3-DOF) magnetically levitated robot and an external manipulation device. To make full use of the range of movement of the multi-degree-of-freedom magnetically levitated robot, we are also developing an simulator system of the robot in parallel. This paper presents the derivation and the configuration of the simulator system and the results of preliminary experiments and simulations which have been performed to evaluate the effectiveness of the simulator.

Development of Master-Slave System for Magnetic Levitation

Abstract Precise works and manipulating micro objects are afflictive for operators both mentally and physically. To execute these jobs smoothly without feeling wrongness, use of master-slave systems is preferable because position and force are able to be scaled up and down under the systems. In our study we develop a master-slave system whose slave robot is micro and levitated by magnetic forces. The distinction of the levitated robot is that it does not get any other contact forces from outside. Thus we introduce a method using an impedance model for constructing the master-slave system. We confirmed the effectiveness of the positioning control algorithm through experiments.

Simplified measurement and visualization tool for crutch walk training

The authors have been developing a crutch walk training system. In this research, there are two fundamental schemes: one is measuring the motions of a patient and crutches, and the other is analyzing these motions. These schemes are expected to be utilized in practical rehabilitation works. In the proposed system, a gyroscope was embedded into a crutch, and the angular velocity of the crutch was measured by it. The measured angular velocities were integrated into tilt angles of the crutch. In this process, the removal of integration error is considered not to be a negligible task. For this task, multiple sensors were used in the previous research. Another task is having patients present walking motions in an easily viewable manner based on the integrated crutchs tilt angle. A still image was presented to patients in the previous research. Therefore, to remove a complexity of multiple sensors and to introduce an intuitive presentation function instead of presenting a still image were required. In this paper, a simplified tool of measurement and visualization was proposed, and its usability was evaluated through experiment.

Double Pressure Presentation for Calligraphy Self-training

The goal of this research is to develop a self-training system of brushwork of calligraphy. In order to draw a well-shaped character, it is required to move the brush properly. In the developed system, the students brushwork is measured by Leapmotion sensor, and if the handwriting is not proper, the students wrist is stimulated. Not only when the brush goes out from the reference trajectory but also when the brush is expected to overrun the proper end-position during one horizontal stroke, the pressure presentation device stimulates the students wrist as an instruction of its handwriting. Experiments with three subjects were carried out, and it was confirmed that the developed system became a more effective device for self-training instruction of calligraphy.

Attending and Observing Robot for Crutch Users

Improper usages of crutches can cause a secondary accident like a falling. In this paper, an instruction robot for crutch walk training is introduced. This robot moves along a walking crutch user, and it measures his/her body parts motions. Based on the measurements, the robot provides advices to the crutch user for proper walk motions. As a result, the crutch user can review his/her own walk motions. It is expected that crutch walk training with this robot will improve the crutch user»s walk motions, and it will decrease the possibility of accidents.

Self-Training System of Calligraphy Brushwork

In this paper, we describe a self-training system of brushwork of calligraphy. For writing a well-shaped character, the brushwork should be controlled properly. In the developed system, the motion of the students brush is measured by Leapmotion sensor, and if the handwriting is not proper, the students wrist is stimulated by a pressure presentation device at the moment as an instruction of a handwriting. Although the mechanism of the developed pressure presentation device was so simple, it could induce the student to correct the handwriting. The developed system can be an effective instruction device for self-training of calligraphy.

Development of Measuring and Guiding Robot for Crutch Walk Training

Patients who are forced to use axillary crutches by sudden accidents usually use them temporally. Although the time period during which the patients require crutches is short, it is desirable that such patients are properly instructed on the proper method of using crutches when the patients start to use crutches. In this paper, a guiding robot for crutch beginners was developed. This robot mainly consists of the Roomba vacuum cleaner and the Kinect sensor. It was designed to move ahead of a crutch user by using the Roomba’s moving mechanism, and to measure the crutch user’s body parts motions by using the Kinect sensor, simultaneously. Some experiments were carried out, and it was confirmed that the developed robot can lead the walking crutch user with keeping a constant distance, and it can determine the before/after stride ratio of the crutch user. The before/after stride ratio will be efficient to evaluate the walk motion stability.