In the ultrasonic motors (USM), there are various driving principles such as a standing wave type, a traveling wave type, etc. Among them, the traveling wave type USM is applied in different devices at various situations, because its shape is like DC (direct current) motors. The control performance is reduction because of the dynamic characteristics of USM, which are greatly fluctuate, depending on the influence of nonlinearity via the friction, frictional heat caused by the driving principle, the magnitude of the load and driving conditions. Up to now, various control methods are proposed, and a lot of researches are conducted to control precision positioning, but a simple method to realize the high positioning performance is not proposed yet. In this research, it is offered a two-degrees-of-freedom control method. It introduces a simple adaptive algorithm which holds the loop gain as a constant value, assuming the steady-state gain is decreased as the reduction of the rotational speed of USM. The characteristic of this method is that the control performance can be compensated with only one gain adjustment. Its effectiveness is verified by experiment which uses USM.
In recent years, an increasing number of care recipients and a shortage of caregivers, by acceleration of declining birthrate and aging, are getting worse. From such social background, the application of the mechatronics technology was expected to reduce the burden on caregivers and the independence of the people requiring nursing care. Therefore, omni-directional moving system that operates intuitively by moving the centroid was developed by this research group. In this study, evaluated, the transient response characteristics and centroid acquisition accuracy of the centroid detection-type movement equipment were evaluated. In addition, the cancellation condition of the boarding standby state for safe boarding was considered. Assuming a load of 60 kg on this equipment, the servo system can be accurately controlled in the range of 2538 to 6345 rpm. At 60 kg load condition, the maximum error distance was only 49 mm. Therefore, the omni-directional mobile system can operate accurately. As the cancellation condition of the boarding standby state, the rest time is necessary to set to 2 sec or more. Moreover, when targeting senior citizens which have low dynamic balance, the rest time is necessary to set still time longer.
We introduce a method for firing nearly invisible, two-dimensional (2D) code on ceramic product surfaces and a 2D code-reader system, equipped with a smartphone and an ultraviolet (UV) light, to extract encoded character information (public and encrypted secret information). We created the nearly invisible 2D code to add character information to ceramic surfaces without impairing the ceramics’ colors and patterns as much as possible. When irradiated by UV light, the code is visible to the naked eye, emitting a pale-blue light. The 2D code-reader system uses a smartphone camera and a 2D code-recognition algorithm to extract character information from the 2D code reflected on the smartphone’s display. However, only smartphones that have access to digital keys can decrypt the encrypted secret information. We successfully fired this 2D code on ceramic surfaces and extracted public and secret information by using iOS and Android-based 2D code-reader system.
In this paper, we discuss injurious bird recognition system that we have developed. Among injurious bird, the damage of Plecoglossus altivelis and Oncorhynchus masou by Phalacrocorax carbo are especially large. In recent years, some researchers have been trying to automatically identify this injurious bird using a surveillance system. However, it was difficult to identify the Phalacrocorax carbo from images including background and other wild birds. Therefore, our research grope examined a method of identification using a convolutional neural network. In order to improve recognition accuracy, learning images were increased by realizing data augmentation of 3 stages. As a result of investigating about this effect, it was able to improve to about 80% of recognition rate.
The straight Darrieus type wind turbine, which is expected to use for dispersed power source in urban site, has low performance especially at low tip speed ratio. In this paper, we suggested new type inner rotor to increase the power coefficient over wide range of tip speed ratio. The new type inner rotor, called “Bach – Comma shaped rotor”, is consist of a combination with cylindrical outer shape and Bach type inner shape. The Bach type shape has straight part to gain more torque from the wind than the classical Savonius bucket. The outer cylindrical shape inhibit the flow separation on the blade and rise the power coefficient. It was verified that the “Bach – Comma shaped rotor” is valid for increase the power coefficient over wide range of tip speed ratio by performing both two-dimensional numerical simulations of flow and the torque measurement experiments under the wind-tunnel.