Tendon-driven mechanisms have gained prominence in a range of applications, including soft robots, exoskeletons, and prosthetic devices. These mechanism use flexible tendons or cables to transmit force and control joint movement. As the popularity of these mechanisms grows, there is an increasing demand for solutions to enhance stability and safety. The use of brakes is a well-known solution, but existing models are difficult to customize for small soft robots. In this paper, we present a one-way shape memory alloy-based compact brake for tendon-driven mechanisms. The proposed soft brake featured a thin design and was tailored for seamless integration within a tendon-driven mechanism. In addition, the use of the one-way shape memory alloys enabled the design of the brakes that are both compact and powerful. This brake is expected to be widely used in miniaturized tendon-driven robots.

The seismic responses of traffic light poles are investigated using a finite element analysis. Among the traffic light poles, single- and bi-directional traffic light poles are considered since such poles are frequently installed on vehicle roads. For a more detailed investigation, three different lengths of the mast arm are considered for each directional pole. For a time-history analysis, six actual and two artificial earthquakes are considered and applied to each direction of the poles (x and y) to investigate which direction input provides more significant responses due to the unsymmetrical structural shape. Herein, the x and y directions are respectively parallel and perpendicular based on the single mast pole case. From the analysis results, the average maximum displacement response is developed with the x-direction input case for both types of light poles. Also, the bi-directional traffic light poles show a 13% larger response than the single-directional traffic light poles. Even though the y-direction input case produces a smaller response, the response difference between the single- and bi-directional light poles considerably increases by about 60%. The average maximum acceleration responses are almost similar for both types of light poles.

This research proposes an optimal flushing operation technique in an effort to prevent secondary water pollutions and accidents in aged pipes, and to improve the cleaning effect of unidirectional flushing. Water flow directions were analyzed using EPANET 2.0, while flushing and air scouring experiments in forward and reverse directions were performed in the field. In 42 experiments, average residual chlorine concentration and turbidity were improved after cleaning compared to before cleaning. It was found that even when the same cleaning method was used, further improvement of cleaning effect was possible by applying air injection and reverse direction cleaning techniques. By means of one-way ANOVA(Analysis of variance), it was also possible to statistically verify the need of actively utilizing air injection and reverse direction cleaning. Based on correlation between turbidity and TSS, the total amount of suspended solids removal was estimated for 874 flushing operations and 194 air scouring operations. The result showed that air scouring used more discharge water than flushing by an average of 4.9 m3 yet with larger amounts of suspended solids removal by an average of 145.9 g. The result of analysis on turbidity values from 887 flushing operations showed low cleaning effect of unidirectional flushing for the pipes with diameters over 300 mm. In addition, the turbidity values measured during cleaning showed an increasing tendency as pipe age increased. The methodology and results of this research are expected to contribute to the efficient maintenance and improvement of water quality in water distribution networks. Follow-up research involving the measurement of water quality at regular time intervals during cleaning would allow a more accurate comparison of discharge water quality characteristics and cleaning effects between different cleaning methods. To this end, it is considered necessary to develop a standardized manual that can be used in the field and to provide relevant trainings.

Three-dimensional motion analysis systems and force plates are used for gait phase detection and ground reaction force(GRF) or ground reaction moment(GRM) data collection. But force plates as measurement systems are restricted to laboratory environments and have limitations for abnormal walking with foot dragging. Therefore the methods were proposed to compute the GRM from the kinematic data of three-dimensional motion analysis systems. Gait phase detection with kinematic data using foot velocity algorithm(FVA) was performed. The validity of gait phase detection was obtained comparing with the results of force plates. A gait model with 7 segments was composed to compute GRM. The results of gait model with kinematic data were compared with those of force plates. The result of the vertical direction is similar. But anterior-posterior direction and lateral direction show similar tendency with some gaps.

At modern mechanical and automotive industry, the material with light weight proceeds in order to thr environmental issue and high performance. Machine part is fastened with numbers of bolts and nuts. Generally, the metal part at mechanical structure is fastened with bolt and nut through puncturing. But it is difficult to puncture at CFRP with the property of fiber structure like the general metal. In this study, the fracture behavior is investigated by the hole and crack at the plate of the unidirectional CFRP due to ply angle. The thickness of plate is 2 mm. Two laminates with the varied ply angles are layered and eight plies are made. The hole is placed at the center of plate and the cracks with the length of 2 mm are generated on both left and right sides from the hole. The finite element program of ANSYS is carried out in order to analyze the CFRP with fiber layer. As analysis, the maximum reaction force and equivalent stress are investigated due the angle of ply. The reaction force in case of the stacking angle of 90° is shown to be greatest among all specimens.

Particulate matters in a water distribution system are main causes of turbidity and discoloration of tap water. They could be removed by conventional or uni-directional flushing in a water distribution system. The behaviors and required flow velocity of particles are not well known for their flushing. A model water main and hydrant were made from transparent acrylic pipe of 30mm and 16mm in diameter, respectively. We analyzed the effect of flushing velocity, particle density, and particle diameter. We found that the existence of break-though velocities at which particles begin to be removed, and which are affected by their physical properties. The removal efficiencies seemed to be influenced by resuspension capabilities related to their upward movement from the bottom. Heavy particles like scale were hard to remove through upflow hydrant because the falling velocity, calculated using Stokes’ law, was higher. Particle removal efficiencies of upward hydrant and downward drain showed minor differences. Additionally, the length between hydrant and control valve affected flushing efficiency because the particulate matters were trapped in this space by inertia and recirculating flow.