Abstract
〈Vol.8 No.4(2015.7)〉

 

Titles
[Special Iuue on The 19th Robotics Symposia]

 

■ Study on Geotechnical Tests with a Lunar Subsurface Explorer Robot using a Peristaltic Crawling Mechanism

Chuo University・Asuka MIZUSHINA, Hayato OMORI, Hiroyuki KITAMOTO,
Taro NAKAMURA, Hisashi OSUMI, and JAXA・Takashi KUBOTA

Recently, planetary investigations have accumulated basic data through various aerospace explorations. However, the investigations of underground such as moonquakes, heat, and conditions of the soil have not revealed much. Therefore, we have developed a novel, small planetary subsurface excavation robot that uses the peristaltic crawling of an earthworm as its underground propulsion method. In this study, we focused on two types of geotechnical tests: pressure meter and shearing tests using the excavation robot. These tests were conducted by measuring displacement and force in the radial and vertical directions, inside the soil, using the excavation robot’s own hardware system. This
paper describes these geotechnical tests, which used the propulsion unit of the robot and measured the soil parameters, e.g., internal friction angle, adhesibility, and elastic constant. From the experiments, we evaluated and discussed results by comparing with reference data. We confirmed that the propulsion unit could measure the soil parameters and propel itself underground at the same time.

 

■ Development of Wearable Training Device with Multiple Degrees of Freedom: Wearable Parallel-Link Measuring Device

Utsunomiya University・Yudai KITANO, and Kazutaka YOKOTA

The authors propose a wrist joint motion measuring device that can be applied to training devices. In this study, the authors described developed a wrist motion measurement method that uses wearable parallel-link mechanisms to continuously measure hand motion in exercise. The proposed method is non-invasive and has a simple mechanism that uses compact linear encoders. The equipment is attached to the human hand and lower arm via a glove and belts. In experiments, the palmar flexion, dorsal flexion, radial flexion, and ulnar flexion motions of 12 subjects were measured, and the results obtained were compared with those from previous anatomical studies. The validity of the proposed method was demonstrated by the results of the experiments.

 

■ Development of a Peristaltic Crawling Inspection Robot for Half-Inch Pipes Using Pneumatic Artificial Muscles

Chuo University・Tatsuya KISHI, Megumi IKEUCHI, and Taro NAKAMURA

This paper describes the development of an in-pipe inspection robot for use in half-inch pipes. Half-inch pipes are commonly used in factories and residences, and in-pipe inspection is essential for preventing accidents caused by burst pipes or corrosion. In-pipe inspection is currently endoscopically conducted; however,endoscopes cannot be inserted into pipes that are more than 15 m long or that have complex shapes, such as elbows. Therefore, various in-pipe inspection robots have been developed, though very few can travel inside half-inch pipes, and none can pass through a 90? elbow. Moreover, no study reports in-pipe robots making long-distance runs within half-inch pipes. The authors have developed a peristaltic crawling inspection robot with pneumatic artificial muscles for use in half-inch pipes; they seek to enable the robot to pass through a 90? elbow and have studied the robot’s ability to travel long distances of more than 15 m.

 

■ Real-Time Projection Mapping Using High-Frame-Rate Structured Light 3D Vision

Hiroshima Universtiy・Jun CHEN,Takashi YAMAMOTO,
Tadayoshi AOYAMA, Takeshi TAKAKI and Idaku ISHII

In this paper, we report on the development of a projection-mapping system that can project RGB light patterns that are enhanced for three-dimensional (3-D) scenes using a graphics processing unit (GPU) based high-frame-rate (HFR) vision system synchronized with HFR projectors. Our system can acquire 512×512 depth-images in real time at 500 fps. The depth-images processing is accelerated by installing a GPU board for parallel processing of a gray-code structured light method using infrared (IR) light patterns projected from an IR projector. Using the computed depth-images, suitable RGB light patterns to be projected are generated in real time for enhanced application tasks. They are projected from an RGB projector as augmented information onto a 3-D scene with pixel-wise correspondence even when the 3-D scene is time-varied. Experimental results obtained from enhanced application tasks for time-varying  3-D scenes such as (1) depth-based color mapping, (2)augmented reality (AR) spirit level and (3) AR wrist watch confirm the efficacy of our system.

 

■ Evaluation of the Effect of Revising the Estimation Procedure of Uncertainty in Dioxin Analysis

Environmental Science Research Niigata・Nobuhiro OYANAGI

Procedure for estimating uncertainty in the analysis of dioxins was revised, and differences in the results obtained between the former and revised procedures were investigated. In the former procedure, uncertainty was estimated from fluctuations in the actual sample data such as the recovery rate of the sampling spike (for a gas sample), duplicate sampling (for a water sample), and replicate tests (for a soil/ash sample). As such, the former procedure differed depending on the sample medium. In the revised procedure, we estimated uncertainty according to a bottom-up approach. Theuncertainty determined in a gas sample and an ash sample using the revised procedure tended to be larger than thatobtained by the former procedure. In a water sample, the uncertainty determined using the revised procedure was smaller than that obtained using the former procedure in low concentration range. These results suggest that (1) the uncertainty using the bottom-up approach may become larger than the actual variation when the maximum estimate of an uncertainty factor is assigned (in this study, the variation in the peak area ratio from GC/MS measurements), and that (2) differences in uncertainty determined by different estimation methods readily occur, particularly in the low concentration range.

 

■ Metalic Surface Inspection Using Lateral Wave Microwave Techniques

JFE Steel Corpration・Junichi YOTSUJI, and
Johns Hopkins University・James B. SPICER

Electromagnetic wave techniques have been used extensively for materials characterization. For techniques that use propagating waves,there are actually three modes for electromagnetic wave transmission from the source to the receiver: direct waves, reflected waves and lateral waves (also known as surface waves).  An interesting characteristic of lateral waves is that they propagate along the boundary between two different materials with the interaction being confined to the boundary region. In this work, the use of lateral waves for remote and non-contacting sensing is considered with an emphasis on characterization of metallic surfaces. The interaction of these waves with near-surface micro-structural features such as cracks or voids is considered showing that lateral waves can be used to detect these features using microwave-based techniques.  While the lateral field strength is small compared to other modes, it is shown that this field is sufficiently large to be useful for crack detection purposes. Experiments on stainless steel plates with slit type defects show model system results for the detection of surface breaking defects using this lateral wave method.

 

■ Formation Control with Collision Avoidance for a Multi-UAV System Using Decentralized MPC and Consensus-Based Control

Keio University・Yasuhiro KURIKI and Toru NAMERIKAWA

IIn this paper, we propose a cooperative formation control strategy with collision-avoidance capability for a multi-unmanned aerial vehicle (UAV) system using decentralized model predictive control (MPC) and consensus-based control. Consensus-based control algorithms are applied for formation flying in three-dimensional space. However, UAVs where these formation control algorithms are applied have not the ability to avoid collisions. Decentralized model predictive control (MPC) is applied to generate control inputs for formation flying with collision-avoidance capability. Using decentralized MPC, each UAV plans only its own action to track the trajectory specified by the formation control algorithm within the feasible regions satisfying collision-avoidance. We show how the optimization problems with coupled constraints such as collision-avoidance can be solved by each decoupled UAV in parallel with the other UAVs so that the decisions independently taken by each UAV can ensure consistency in coupled constraints of collision-avoidance. The computation time is also taken into account because it is a crucial factor to apply MPC to actual UAVs. Finally, the proposed approach is validated by some simulations.

 

■ Hierarchical Decentralized Controller Synthesis for Heterogeneous Multi-Agent Dynamical Systems by LQR

Hanoi University of Science and Technology・Dinh-Hoa NGUYEN and
The University of Tokyo Shinji HARA

This paper is concerned with systematic ways of designing hierarchicaldecentralized controllers for heterogeneous multi-agent dynamical systems. Given a bunch of indepen dent agents or subsystems with a class of information networks, our aim is to propose a systematic design procedure for hierarchical decentralized controllers, where each subsystem cooperatively interacts with each other as well as controls it locally to achieve both the local and global goals in some senses.It is shown that employing the LQR (Linear Quadratic Regulator) method with properly chosen weighting matrices in the performance index, both the local and global objectives can be achieved by the desired hierarchical decentralized structure which fits to the given information network. The effectiveness of the proposed design method is confirmed through an illustrative example and its application to a velocity consensus problem in vehicle platoons.