High-Speed Acoustic Network for Seafloor Geodetic Observation Robot System

The Delta robot system is widely used in high speed (4 cycles/s at 25-200-25 mm) pick-and-place process in production line. Some industrial applications include photo-voltaic (PV), food process, and electronic assembly, and so on. The energy saving and system cost are two critical parameters for designing the next generation of pick-and-place system. To achieve these goals, a light-weight moving structure with sufficient strength to overcome the excited vibration will be one of the solutions. In this paper, an asymmetric arm design is proposed and fabricated to gain the benefit of strength-to-weight. The asymmetric arm is designed by reinforcing a specific direction and is validated the vibration suppression capability both by simulation and experiment. A position controller that is derived from the kinematic model of Delta robot is utilized to manipulate the robot under a forward-backward motion with a polynomial trajectory with 200 mm displacement. The residual vibration, then, was measured after the forward-backward motion to compare the settling performance between symmetric- and asymmetric-arms on the Delta robot system, respectively. The results conclude as following: (1) The asymmetric arms perform slightly worse (0.03 sec more in settling time) than symmetric arm but there is 15% weight reducing comparing to symmetric arm. (2) Both energy saving and system cost reducing would be achieved by utilizing actuators with lower power consumption and fabrication on carbon fiber arms with mass customization.

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Routine seafloor geodetic observation around Japan

Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat No 04EX869) UT-04 ◽

10.1109/ut.2004.1405619 ◽

2005 ◽

Cited By ~ 1

Author(s):

M. Mochizuki ◽

M. Fujita ◽

M. Sato ◽

Z. Yoshida ◽

T. Yabuki ◽

...

Keyword(s):

Geodetic Observation ◽

Seafloor Geodetic Observation

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Crustal Deformation Detection Capability Associated With a Fault Slip on the Interplate Boundary in the Gnss-a Seafloor Geodetic Observation Array (SGO-A), Provided By Japan Coast Guard

10.21203/rs.3.rs-783404/v1 ◽

2021 ◽

Author(s):

Yusuke Yokota ◽

Tadashi Ishikawa ◽

Sun-ichi Watanabe ◽

Yuto Nakamura

Keyword(s):

Standard Deviation ◽

Crustal Deformation ◽

Deformation Rate ◽

Coast Guard ◽

Detection Sensitivity ◽

Japan Trench ◽

Detection Capability ◽

Geodetic Observation ◽

Seafloor Geodetic Observation ◽

Slip Event

Abstract The GNSS-A technique is an observation method that can detect seafloor crustal deformations with centimeter level accuracy. The GNSS-A seafloor geodetic observation array operated by the Japan Coast Guard, called SGO-A, has been constructed near the Japan Islands along the Nankai Trough and the Japan Trench. This observation array has detected several earthquakes’ displacements and episodic slow crustal deformation. To compare the detection results of SGO-A with other observation networks and expand the SGO-A distribution, it is necessary to correctly understand its detection capability. In this paper, the capabilities of current GNSS-A (frequency: f = 4–6 times/year, position accuracy: σ (standard deviation) = 1.5 cm) to detect a crustal deformation rate only, an event only, and crustal deformation rate and event together were arranged by numerical simulations. Results suggested the following features: when it is known that there is no event, the 95% confidence level (CL) for the estimation of crustal deformation rate with 4-year observation is about 0.5–0.8 cm/year; when the deformation rate is known, a signal of about 3.0 cm can be detected by observations of about 4 times before and after the event. When the deformation rate and the event are detected together, to keep the false positive low (about 0.05), the false negative becomes high (about 0.2–0.7 for detecting a signal of 4.5–6.0 cm). The determined rate and event variations are approximately 1.8 cm/year (95%CL) and 1.5 cm (standard deviation), respectively. We also examined the detection capability for higher frequency and accuracy, to examine how the detection capability improves by technological advancements in the future. Additionally, we calculated the spatial range of event detectability using the determined values of detection sensitivity. Each seafloor site can detect a slip event larger than 0.1 m scale within about 50 km radius. A subseafloor slip event smaller than about 1 m at the distance of 100 km or more from the land can often be detected only on the seafloor observation array.

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Motion Generation for a Sword-Fighting Robot Based on Quick Detection of Opposite Player’s Initial Motions

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2015.p0543 ◽

2015 ◽

Vol 27 (5) ◽

pp. 543-551 ◽

Cited By ~ 4

Author(s):

Akio Namiki ◽

◽

Fumiyasu Takahashi

Keyword(s):

Least Squares ◽

High Speed ◽

Least Squares Method ◽

Vision System ◽

Experimental Results ◽

Change Points ◽

Motion Generation ◽

Robot System ◽

The Moment ◽

Human Player

<div class=""abs_img""> <img src=""[disp_template_path]/JRM/abst-image/00270005/11.jpg"" width=""300"" /> Defensive motion against attack</div> In this paper, we discuss how to generate defensive motions for a sword-fighting robot based on quick detection of the opposite player’s initial motions. Our sword-fighting robot system, which has a stereo high-speed vision system, recognizes both the position of a human player and that of the sword grasped by the robot’s hand. Further, it detects the moment when the human player initiates a move using ChangeFinder, which is a method of detecting change points. Next, using least squares method, it predicts the possible trajectories of the sword of the human player from the moment when the attack starts. Finally, it judges the type of the attack and generates an appropriate defensive motion. The effectiveness of the proposed algorithm is verified by experimental results. </span>

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