Masao Miyagi

Mobile robot system to aid the daily life for bedridden persons

The number of old-aged people in the population is increasing in Japan, the problem of caring for bedridden patients will increasingly become a social problem. We are trying to solve this problem by developing a small mobile robot system for bedridden patients. The purpose of this system is to pick up and place a small object somewhere inside the room semi-automatically. This mobile robot consists of a manipulator, visual sensor unit and mobile unit. This system gives information about the surrounding to the patient through the camera and monitor. When the patient directs a target object on the monitor, the system measures the 3-dimensional location of it, the mobile unit then approaches the object and the manipulator picks it up and carries it back to the patient. This system is controlled by the image information and also by the human operator (the patient) through an image based interface.

Quantification of skin aging by three-dimensional measurement of skin surface contour

In order to quantify the skin aging, the skin surface contours for 72 male subjects from in his 20s to in his 60s were measured three-dimensionally and analyzed by 2D Fourier transform method. The measuring part of the body was the back of the hand. Results of the 3D measurements showed that the pattern composed of longitudinal, oblique, and transverse ridges on the skin surface changed with age. Results of the 2D Fourier analysis of skin surface contours showed that the skin surface contours of young male subjects included much of high spatial frequency components while the skin surface contours of aged male subjects included low spatial frequency components mainly. The aging parameter for 72 male subjects, which expressed the skin aging quantitatively, was calculated by summing up the Fourier coefficients within a specified area on the X-Y spatial frequency plane. The aging parameter decreased with age. However the aging parameter showed wide scattering. The wide scattering of the aging parameter can be removed by applying the high pass digital filter to the skin surface contours.

Measuring method of three-dimensional position and orientation of a moving object for medical robots

A measuring method of 3-D position and orientation of a moving object has been developed, which employed a 2-D position measuring instrument (with only one camera) and three light points attached to the moving object. In order to increase the accuracy of the 3-D measurement, the positions of pupils of the optical system for the 2-D position measuring instrument were introduced to derive the theoretical equations, and the geometrical relation between three light points in the object space was determined experimentally using the 2-D position measuring instrument before conducting 3-D measurements. Based on the principle of our measuring method, static 3-D measurements were conducted. The results showed that the maximum measurement errors of the X, Y, and Z coordinates of three light points were 0.05 mm, 0.1 mm, and 3 mm respectively within the measuring range from Z=-360 mm to 2=-760 mm. The accuracy of the measurement will be increased to the resolution of the 2-D position measuring instrument by improving the experimental apparatus and method.

Development of the system to teach the bedsore prevention method for wheelchair users

In this study, we are developing the system to teach bedsores prevention method for wheelchair users. This system can measure the distribution of pressure by the sensor sheet when a wheelchair user sits on it, and show the measured result on the monitor by the color image. Therefore, wheelchair users are able to learn the bedsores prevention method under recognizing their distributions of pressure with the therapist. We measured pressure distribution and got differences between SCI people and AB people using this system, and we confirmed that it is important to measure pressure distributions and this system is useful to use when therapist teach the bedsore prevention method to wheelchair users.