Conventional knee supporters generally reduce knee pain by restricting joint movement. In other words, there were no mechanical knee supporters that functioned powerfully. Considering this problem, we first devised a device in which a spring is inserted into the double structure of the cylinder and piston, and a braking action is applied to the piston. This mechanism retracts when the knee angle exceeds a certain level. Next, the knee and the device were modeled, and the dynamic characteristics of the device were investigated to find effective elements for knee shock absorption. Although various skeletal and muscular structures have been studied for the knee section, we kept the configuration as simple as possible to find effective elements for the device. A shock-absorbing circuit was devised, and air was used as the working fluid to facilitate smooth knee motion except during shock. Increasing the spring constant effectively reduced the knee load.
Conventional ergonomics utilizes second-order control systems and three-dimensional models, but their complexity makes them unsuitable for practical development. In this paper, a simple mechanism for lifting objects by temporarily setting the load to zero was devised by applying basic techniques of kobujutsu (Japanese ancient martial arts). The accuracy of this mechanism was confirmed by simulation and experiment. This mechanism reveals that the speed of reflection of signals by the brain is important to essentially increase the output of human muscles, enabling efficient and simple movements. It is suggested that the method of lifting objects revealed in this paper is not limited to martial arts and other sports fields but could be applied to a wide range of fields such as nursing care and agricultural work. The development and evaluation of the simple object lifting technique demonstrated in this paper is expected to activate and improve the motor skills of the public and have a positive impact on health maintenance activities.
Trawling is one of the most common fishing methods used by small vessels. This method requires the vessel to operate at a constant low speed because the depth of the trawl must be kept constant. In addition, the operation is often conducted by a small number of people, who must simultaneously maneuver the vessel and fish, making automation desirable. To develop this device, a mathematical model of the vessel was created based on data collected from actual operation of the vessel, and simulations were conducted to determine what type of control system would be suitable. As a result, it was possible to grasp effective control methods, effects of disturbances such as tides and waves, and how to deal with effective parts to improve response.
Most of the fishing currently practiced in Japan is done by small vessels with a small number of fishermen (one or two). One of the most common fishing methods is longline fishing. However, this method requires the vessel to operate at a constant low speed because the depth of the hook must be kept constant while adjusting the speed of the fishing boat to the tidal current. In addition, because the vessel must maneuver and fish at the same time, automation is desired. Thus, we propose a robotic system that can control the depth of the trap at a constant depth even when the speed of the vessel and the current change, and that can successfully fish without the need for skilled fishermen. Fishing can be conducted regardless of the speed of the vessel, whereas currently it is controlled by the speed of the vessel and the tidal current. Therefore, it may contribute to proposing new fishing methods as well as the existing ones. This can contribute to the shortage of successors to the fishing industry and to the revitalization of the fishing industry.
Abstract. Orono-shima Island is a remote Island in the Tsushima Strait, it is 4.3km around. Since ancient times, it has been a landmark when crossing from the Korean Peninsula to Japanese archipelago via Tsushima Island and Iki Island. However, large-scale ruins and burial mounds are not known on Orono-shima Island until now. During my four years on the island, the author walked all over the island for terrain survey. As a result, the author discovered a topography like keyhole tomb which is a characteristic Japanese burial mound, on the northern cape of the island. It could be up to 150m in size, one of the largest around Kyusyu Island. There is no burial mound comparable to this on a remote island in Japan. Therefore, we created a 3D image using a drone Laser surveying of this terrain and we compared the results with another keyhole tomb. In addition, we analyzed the image of infrared radiation of Orono-shima Island took by Landsat8. In conclusion, it was speculated that this topography was the prototype of the oldest type of keyhole cairn tomb in Japan. The topography of the northern part of Orono-shima could be regaining the missing link between the cairn on the Korean Peninsula of the first century and the oldest type of keyhole cairn tomb in Japan of the third century.
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