Takakazu Ishimatsu

Modeling of a stair-climbing wheelchair mechanism with high single-step capability

In the field of providing mobility for the elderly and disabled, the aspect of dealing with stairs continues largely unresolved. This paper focuses on presenting the development of a stair-climbing wheelchair mechanism with high single-step capability. The mechanism is based on front and rear wheel clusters connected to the base (chair) via powered linkages so as to permit both autonomous stair ascent and descent in the forward direction, and high single-step functionality for such as direct entry to and from a van. Primary considerations were inherent stability, provision of a mechanism that is physically no larger than a standard powered wheelchair, aesthetics, and being based on readily available low-cost components.

Computer interface to use head and eyeball movement for handicapped people

In this paper we propose a computer interface device for handicapped people. Input signals of the interface device are movements of eyeballs and head of the handicapped. The movements of the eyeballs and head are detected by an image processing system. One feature of our system is that the operator is not obliged to wear any burdensome device like glasses and a helmet. The sensing performance of the image processing of the eyeballs and head is evaluated through experiments. Experimental results reveal the applicability of our system.

Muscle stiffness sensor to control an assistance device for the disabled

An innovative sensor has been developed as a man–machine interface to control an assistance device for people with disabilities. This sensor is applied to a mechanical glove that has a grasping function, and its usefulness is demonstrated through experiments. The sensor is attached to the operator’s skin and detects noninvasively how much the muscle under the sensor has stiffened.

Asparagus harvesting robot coordinated with 3-D vision sensor

We are developing an automated asparagus harvesting robot to support manual labor works. Our robot is composed of a 3-D vision sensor, a robotic arm and a drive mechanism on the agricultural land. The 3-D vision sensor measures the cross-section of the asparagus and determines the target asparagus. The robotic arm grasps the asparagus and cut the stem. By using the drive mechanism on the agricultural land our robot can navigate along the asparagus cultivation furrow. Experimental results in the greenhouse reveal the applicability of our robot.

Chewing number is related to incremental increases in body weight from 20 years of age in Japanese middle‐aged adults

BACKGROUND Eating habits are associated with both current obesity and incremental increases in body weight from young adulthood, but no study has focused on chewing number during meals among community residents. OBJECTIVE This study focused on the relationship between chewing number and incremental increases in body weight from 20 years of age. METHODS A total of 93 persons aged 35-61 years participated. The subjects were asked to set the device and record their chewing number during each meal on a particular day. They were also asked whether their body weight had increased by 10 kg or more since they were 20 years old. RESULTS The body weight of 28 subjects (30%) had increased more than 10 kg since the age of 20 years. Total chewing number showed a relationship with such body weight increases. The odds ratio of weight increments of more than 10 kg for the lowest tertile group was 4.6 [95% confidence interval (CI), 1.3-16.2] relative to the highest tertile group (Model 1). The odds ratio of weight increments for the lowest tertile group increased to 6.3 (95% CI, 1.6-25.4) in Model 2 and to 9.1 (95% CI, 1.7-49.8) in Model 3. CONCLUSION Although this study was limited because it did not consider all risk factors, categorical chewing number was related independently to body weight increments of more than 10 kg from 20 years of age.

Rapid Generation of Surface Dimples Using End Milling

Rapid Generation of Surface Dimples using End Milling Shinichi KOGUSU, Takakazu ISHIMATSU and Yasuhiko OGIYA Structured surfaces on metal are often employed to enhance lubricating features, reduce the hydrodynamic drag force along wings and also decorate the metal surfaces for architectural ornament. It is important to note that even single movements of a ball-end mill parallel to the metal surface generate the indented surface on the metal surface based on the cutting condition. In this paper a technique to determine the cutting condition to generate the desired dimpled surface is proposed. The design specifications of the dimpled surface are the width of the dimples and the spacing between the dimples. The proposed technique was successfully used to decorate metal surfaces.

Auto-navigation of a wheelchair

This paper presents an autonomous wheelchair system with the capability of self-localization and obstacle avoidance. In our system, the ceiling lights are chosen as landmarks to realize the self-localization of the wheelchair, and a laser range-finder is used for obstacle avoidance. First the approaches of landmark recognition and selflocalization for the wheelchair are proposed. Then the principle of obstacle avoidance using a laser range-finder is described. Finally, the total system of the wheelchair is introduced and a navigational experiment is described. Experimental results indicate the effectiveness of our system.

Unbalance compensation of magnetic bearings

In a rotational machine, unbalance of the rotor is formidable since it causes resonance synchronized with the rotation of the rotor. In order to suppress this unfavorable vibration, an active vibration control system, which accommodates changes of rotor dynamics is desired. In this paper we propose a vibration control system using active magnetic bearings to cope with a sudden sinusoidal disturbance, which simulates a turbine blade loss. Experimental results reveal that our vibration control system is effective enough to suppress the whirling motion of the rotor caused by a sudden disturbance.<<ETX>>

Computer interface device for handicapped people using head movement

In this paper we propose a computer interface device for physically handicapped people, which enables the operator to communicate with the computer without typing on the computer keyboard. Input signals of the interface device are movement of the head. The movement of the head is used as a positioning signal of the computer cursor on the computer monitor. The system is realized on one field programmable gate array (FPGA) in order to realize the system in a compact body. Using this interface device, we built an environmental control system and also a word processing system. Experimental results reveal the applicability of our system to physically handicapped people.

3-D measurement of moving particles by circular image shifting

A new approach to the three-dimensional (3-D) measurement of position and velocity of moving particles is introduced. A single TV camera with an apparatus to add circular shift to the image enables us to record the 3-D movement of particles as spiral streaks on a single image. Every shape of the spiral streak on the image plane is related to the position and the velocity of the individual particle. The information about 3-D movement of particles is extracted from the image using an image processing technique. We applied the technique to the measurement of the 3-D water-flow field seeded with tracer particles in a test tank and obtained satisfactory results.