Due to the ageing and the decreasing birth rate in Japanese society, an important problem of providing nursing care for the elderly has occurred. Therefore, it is strongly desired to develop a wearable actuator to use in nursing care or rehabilitation. The purpose of this study is to develop a high-power flexible actuator with a displacement sensor which can be used in supporting a bathing. In our previous study, we proposed and tested a rubber artificial muscle with the inner diameter sensor. The inner diameter sensor consists of two electric circuit boards with two photo reflectors. Two boards are bonded together to contract the inner diameter sensor. The sensor also has a doughnutshaped bulkhead to keep a seal. The sensor is inserted into the tube of the artificial muscle. The senor is set at the end of tube. This sensor can be expected to estimate the axial direction displacement of the rubber artificial muscle, because the relation between the inner diameter and the axial directional displacement of the muscle has a strong correlation. However, if the external bending force is applied to the end of the muscle, the inner diameter sensor cannot hold at the center position of the tube. Therefore, the sensor cannot measure the inner diameter exactly. In this study, the improvement of the inner diameter sensor was executed. The improved sensor has 4 photo reflectors on the two electric circuit boards to compensate the measuring error. The position control was also carried out by using the actuator with the built-in inner diameter sensor. As a result, the axial direction displacement of the muscle could be estimated well by the tested inner diameter sensor, and a relatively good position control performance was obtained.

In designing and manufacturing such robotic and mechatronic systems, the engineers need a wide range of knowledge that includes electronics, mechanical engineering and information engineering. The purpose of this education is for students to give active learning for robotics and mechatronic techniques such as embedded controllers, motor driver circuits, sensors and to create structural drawings. To realize this goal, “an interest in creation” of student is regarded as an important educational method. In this paper, a systematic educational method for robotics and mechatronics education using “their interest” was introduced. The method is to hold robot competitions every year between 1st and 3rd year students as a regular part of the curriculum. To confirm the educational effect of this curriculum, the result of the Rescue Robot Contest that students participated were introduced. In addition, the educational curriculum was award as a good engineering education from Japanese Society for Engineering Education. As a result, it can be confirmed that the robot competition is a useful method to make students study more actively robotics and mechatronics technology by themselves.

The actuators for such a wearable device need to be flexible so as not to injure the body. The purpose of our study is to develop a flexible and lightweight actuator and a compact control device that can be safe and light enough to be attached to the human body. In this study, we proposed and tested a new type of flexible potentiometer using nylon string coated with carbon. As a result, we found that the tested sensor that can detect the displacement of the McKibben actuator so as not to lose the flexibility of the actuator

Due to the recent ageing and decreasing birthrate of the Japanese society, providing nursing care for the elderly has become very crucial. As a result, it is necessary to develop wearable systems to aid in nursing care. To realize such a system, we require not only wearable soft actuators, but also a compact and flexible control valve that can drive a soft actuator such as a pneumatic artificial muscle. The purpose of our study is to develop a flexible, lightweight and compact control valve which can be safely attached to the human body. In this study, we proposed and tested a new type of control valve. The valve consists of a vibration motor and a check valve that is made of a steel ball and an orifice in a flexible tube. The operating principle of the valve is as follows. The valve is normally closed as a function of the check valve. When vibration is applied, the inner ball in the check valve moves and the valve opens. By giving continuous vibration, the valve can be kept open. As a result, we find that the valve can control a larger flow rate relative to its weight and size. As an application of the tested valve, we apply the control device to a wearable actuator in the form of a McKibben artificial muscle.