Shujiro Dohta

Development of small sized multi-port pressure control valve for wearable actuator

Recently, a virtual reality system and a power assisted system are paid much attention and are researched actively. In such a control system, an actuator and a driving device, such as a control valve, are mounted on the human body. Therefore, the actuator and driving system should be compact, lightweight and flexible so as not to impose an excessive load and not to injure the human body. The purpose of our study is to develop a wearable and compact driving system that uses a flexible and lightweight actuator, which can be safe enough to be attached to the human body. We proposed and tested new types of flexible pneumatic actuators that can be used even if the actuator is deformed by external force. In this study, we proposed and developed a multi-port pressure control valve, which can drive many wearable actuators at the same time to reduce the weight of the control valve for multi-degrees of freedom of motion.

Development of Tetrahedral Type Rehabilitation Device Using Flexible Pneumatic Actuators

Rehabilitation devices help to recover physical ability of patients. This study aims to develop a home rehabilitation device which can be safe to use while patients are holding it by hands. In the previous study, as a portable rehabilitation device, the flexible spherical actuator that was able to give motions to patients while handling it was developed. The device can give rehabilitation motion for upper limb by only changing the relative position of patient’s hands. However, the tested device cannot give absolute position for hands for rehabilitation of shoulders. In this study, we aim to develop a low-cost and simple home rehabilitation device for shoulder that can change absolute position of the device. In this paper, to realize position change of the flexible spherical actuator, the development of a tetrahedral type rehabilitation device using extension type flexible pneumatic actuators is described. The construction and the operating principle of the tested device is also described. The attitude control using the tested device and an embedded controller is also carried out. As a result, it can be confirmed that the absolute position of the object can trace the desired coordinate relatively well. 

Improvement of a Pneumatic Control Valve with Self-Holding Function

The purpose of this study is to develop a small-sized, lightweight and low-cost control valve with low energy consumption and to apply it to the assistive system. We have developed some control valves; a tiny on/off valve using a vibration motor, and an on/off valve with self-holding function. We have also proposed and tested the digital servo valve with self-holding function using permanent magnets and a small-sized servo motor. In this paper, in order to improve the valve, an analytical model of the digital servo valve is proposed. And the simulated results by using the analytical model and identified parameters were compared with the experimental results. Then, the improved digital servo valve was designed based on the calculated results and tested. As a result, we realized the digital servo valve that can control the flow rate more precisely while maintaining its volume and weight compared with the previous valve. As an application of the improved valve, a position control system of rubber artificial muscle was built and the position control was performed successfully.

Development of the Manipulator for Special Environment

Recent years, image diagnosis of non-reliability has been rapidly developed, some of which it is possible to acquire the image of the time series. It is necessary to fix by, for example subjects or the shooting object is gripped by the MRI internally, within the MRI gantry is unable to use the common actuator for the strong magnetic field. In this study, the pneumatic bending actuator manipulator for magnetic resonance imaging (MRI), a noninvasive medical diagnostic imaging technique, was evaluated for a posture holder and a flow phantom experiment apparatus.

0709 Development and Application of Flexible Pneumatic Cylinder with Linear Encoder

The wearable actuator needs to be flexible so as not to injure the human body. We aim to develop a flexible and lightweight actuator which can be safe enough to be attached to the human body. We have proposed new types of flexible pneumatic actuators that can be used even if the actuator is deformed by external forces. We also tested a robot arm using the tested flexible pneumatic cylinders. In the next step, the actuator should be able to measure its displacement to realize the higher control performance. The purpose of this study is to develop the displacement sensor for the flexible actuator and to combine it with the actuator. In this paper, we develop a flexible linear encoder that can measure the displacement of the flexible pneumatic cylinder using four photo-reflectors. They can detect the state of bending tube to compensate the sensor output even if the tube is bent. In addition, we develop a flexible pneumatic cylinder with a built-in linear encoder. As a result, we confirm that the tested cylinder can be realized even if the cylinder tube is affected by the disturbance while driving.

1007 Development of a Search Type Rescue Robot Driven by Pneumatic Actuator

Recently, the large earthquake including Hanshin-Awaji (Kobe) Earthquake has occurred. A lot of lives have been lost due to these earthquakes. In order to find and save victims even one, many researches and developments of the rescue robot have been done. In such studies, most of the rescue robot used the electric actuator for travelling. In those cases, there is a possibility of getting an electric shock because of electricity. Comparing with electric actuators, the pneumatic and flexible actuators and devices can make the robot stronger against the electric shock and physical shock. In this study, we aim to develop the search type rescue robot with flexible structure. We propose two types of robot. First, we propose and test a lightweight and compact search type rescue robot using the flexible pneumatic cylinder and crawler unit. Second, we propose and test the rescue robot using a pneumatic motor and the long stroke type artificial rubber muscles. This paper describes the structure, the principle of operation and the performance of the tested robots.