The effects of high-pressure sintering on the critical current density J c in superconducting wires of (Ba 0.6 K 0.4 )Fe 2 As 2 and (Sr 0.6 K 0.4 )Fe 2 As 2 fabricated by the powder-in-tube technique were studied. The high-pressure sintering was conducted using the hot isostatic pressing (HIP) technique in a pressure up to 120 MPa. Local measurements on the magnetic induction distribution of the wire core in the critical state using magnetooptical imaging demonstrate that a uniform shielding current is flowing and intergranular couplings are very strong. Self-field J c up to 1 × 10 5 A/cm 2 is achieved in wires processed at 120 MPa and 700°C. A systematic measurement of J c in HIP-processed (Ba 0.6 K 0.4 )Fe 2 As 2 wires demonstrates that J c increases steadily with the pressure during the high-pressure sintering. On the other hand, the obtained J c depends sensitively on the temperature during the high-pressure sintering, and the duration of the high-pressure sintering also affects the value of J c .

High-quality single crystals of iron–platinum arsenides Ca10(PtnAs8)(Fe2−xPtxAs2)5 (n=3, 4) have been grown and their superconducting properties are characterized. The n=4 and n=3 compounds have Tc’s∼30K and 13K, respectively. Reflecting a modest anisotropy of the system, resistive transition for H//c-axis shows modest broadening in both systems. Magneto-optical imaging shows that superconductivity in both compounds is rather homogeneous, with the critical current density, Jc, ∼1×105A/cm2 at 5K under self-field. Proton irradiation up to 4×1016cm−2 into n=3 compound is found to have Tc suppression by ∼2K and Jc enhancement by a factor of three at low temperatures.

The critical current density, J c , in high-quality single crystals of iron-based superconductors (IBS) has reached larger than 10 5 A/cm 2 at 4.2 K. This large value of J c urged the development of potential superconducting wires or tapes based on IBS. We have fabricated superconducting wires and tapes of IBS using several techniques and made an extensive characterization by structural, transport, and magnetic measurements. The powder-in-tube method is used for (Ba, K)Fe 2 As 2 and Ba(Fe, Co) 2 As 2 wires and the diffusion method is used for FeSe tape. Intra- and inter-granular J c 's have been evaluated by direct transport and indirect magnetization measurements as well as using magneto-optical (MO) imaging. The intergranular J c 's at 4.2 K under self-field for (Ba, K)Fe 2 As 2 and Ba(Fe, Co) 2 As 2 wires and FeSe tapes are 1.3 × 10 4 A/cm 2 , 3.8 × 10 3 A/cm 2 , and 600 A/cm 2 , respectively. On the other hand, MO images have demonstrated that the intragranular J c is at least one order of magnitude larger than the intergranular J c , which is consistent with the magnetic evaluation.

The optical and vibrational properties of BaTi2O5 glass prepared by containerless processing were investigated. The refractive index was 2.15 and the Abbe number was 21.5, as measured by the focal method. The glass was transparent from 340 nm to 7.7 μm. From the Raman scattering spectrum, the maximum phonon energy was found to be 829 cm−1. Using these data, fundamental optical parameters such as the optical basicity, the average oscillator strength, and the optical band gap were estimated. These parameters suggest that BaTi2O5 glass is an attractive material with many potential applications such as lenses, windows, nonlinear optics, and phosphors; moreover, these parameters can guide future development of new titanate glass compositions with superior optical properties.

We introduce a concept of a real-world-oriented humanoid robot that can support humans' activities in daily life. In such environments, robots have to watch humans, understand their behavior, and support their daily life tasks. In particular, these robots must be capable of such real-world behavior as handling tableware and delivering daily commodities by hand. We developed a humanoid robot, HRP-2W, which has an upper body of HRP-2 [K. Kaneko, F. Kanehiro, S. Kajita, H. Hirukawa, T. Kawasaki, M. Hirata, K. Akachi, T. Isozumi, Humanoid Robot HRP-2, in: Proceedings of the 2004 IEEE International Conference on Robotics & Automation, 2004, pp. 1083-1090] and a wheel module instead of legs, as a research platform to fulfill this aim, We also developed basic software configuration in order to integrate our platform with other research groups. Through experiments, we demonstrated the feasibility of the humanoid robot platform and the potential of the software architecture. (C) 2008 Elsevier B.V. All rights reserved.

|We present an interactive manipulation path planner under development for providing high-level task-based control for humanoid robots. Using a graphical simulation environment, the software is designed to facilitate the automation of object grasping and manipulation tasks. A randomized path planner is used to directly search the free con guration space of the robot for a collision-free manipulation path. Experimental results are shown using a model of the dynamic humanoid \H6" robot in a virtual world.

This paper overviews a robotics project at the Expo 2005. The project consists of long term experimental evaluation of practical robots at the Expo site simulating the society in the future and short term demonstration of prototype robots. The long term evaluation can let robots advance from the demonstration level to the practical use one, and the short term demonstration from the single shot experiment level to the demonstration one.

This paper gives an overview of the humanoid robot ‘H7’, which was developed over several years as an experimental platform for walking, autonomous behaviour and human interaction research at the University of Tokyo. H7 was designed to be a human-sized robot capable of operating autonomously in indoor environments designed for humans. The hardware is relatively simple to operate and conduct research on, particularly with respect to the hierarchical design of its control architecture. We describe the overall design goals and methodology, along with a summary of its online walking capabilities, autonomous vision-based behaviours and automatic motion planning. We show experimental results obtained by implementations running within a simulation environment as well as on the actual robot hardware.

This paper proposes wave-shape pattern control method for whole-body deformable robots containing electroactive polymers. Mechanisms consisting of a typical electroactive polymer gel containing poly 2 -acrylamido -2- methylpropane sulfonic acid (PAMPS), named ‘gel robots’, have been designed, developed, and controlled experimentally. We faced a common problem called, the degrees-of-freedom problem, namely controlling many points on the gel surface with a small number of inputs. In order to solve the problem, we once reduced the number of inputs to one, and discovered that wave-shape pattern evolves for the beam-shaped gel even in a constant uniform electric field. This method makes use of the pattern formation. Wave-shaped gels with varying curvature are obtained by switching the polarity of a spatially uniform electric field. The method is verified through experiments which are carefully designed based on numerical simulations.

This paper addresses a method of constructing a control system that realizes desired absolute hand position trajectory while walking. Controlling hand position in the absolute coordinate system with short delay while walking is a important function for realizing such motions as visual feedback reaching while walking, walking using handrail, and opening doors while walking. Based on previously developed online walking control system, fast dynamically stable walking trajectory generation system that preserves designed hand trajectory in absolute coordinate system, and sensor feedback balance maintaining system that also preserves given hand position are developed. Then a torso transition planner that generates desired torso movement of every one step from the absolute hand trajectory is implemented. A hand position operation experiment with "3D mouse", a reaching experiment with visual feedback, and a guiding experiment using 6-axis force sensor at wrists are shown to demonstrate the performance of the system.

We propose a design of musculo-skeletal humanoid whose muscles can be easily added, removed, or re-arranged, which can be compared to the ability of growing up of a human’s (or an animal’s) body. This paper presents a design and development of the reconfigurable complex-body robot, and a method to build a system which can acquire the body information and can be used for realization of motions of human-like nonlinear musculo-skeletal robots. It shows that even reconfigurable complex-body robot’s motion can be achieved by a feedback modification method in conjunction with neural network. We did basic validation experiments by giving target postures one by one, measuring the realized postures, and comparing them with the target postures. We also carried out whole-body motion experiments using motion captured sequences using the presented system.

This paper describes an online system for footstep planning using a 3D map reconstructed by visual odometry. This system consists of two key components: 3D reconstruction via visual odometry from a stereo image sequence to obtain a dense local world model, and a footstep planner for biped robots using the reconstructed 3D map. Visual odometry is a method to connect 3D image sequences to obtain 6DOF camera motion and dense 3D environment information. The method described in this paper consists of three components: stereo depth map calculation, 3D flow calculation from tracking raw image features, and 6DOF camera motion estimation from RANSAC. Using the resulting 3D data, an optimal sequence of footstep locations is planned. The footstep planner is provided a height map of the terrain and a discrete set of possible footstep motions. The planner then evaluates footstep locations for viability using a collection of heuristic metrics designed to encode the relative safety, effort required, and overall motion complexity. Finally, we implemented this system on the humanoid robot H7. A local 3D map is reconstructed using visual odometry at about 10 Hz and the footstep planner replans at intervals of four steps. The robot walked across a floor, avoiding obstacles and reaching the goal.

This paper addresses a control system for the coordination of whole body motion with hand manipulation. The goal is to control the position of the hand and/or external force at the hand. Whole-body motion control is necessary for both maintaining balance and realizing a wide workspace. Turning a crank is selected as the manipulation task. We describe a control strategy for turning the crank. We present a torso position and posture control method for extending the workspace while maintaining balance. Furthermore we demonstrate a stable walking control system that operates concurrently with manipulation and enables further expansion of the workspace. Experiments on a full-size humanoid are presented to demonstrate the performance of the system.

This paper describes a 32 /spl times/ 32 matrix scan type high-speed pressure sensor for the feet of humanoid robots that has 1 kHz sampling rate. This sensor has matrix scan circuit. The matrix scan method has a problem of interference by bypass current. To resolve this problem, we suggest a novel method using a very thin conductive rubber. We adopted a very thin (0.6 mm) force sensing conductive rubber sheet for high speed sensing. Each sensing area is 4.2 /spl times/ 7.0 mm and can measure vertical force of approximately 0.25-20 N. Walking cycle of humanoid robot as well as human being is about 0.4-0.8 s and dual leg phase is about 0.1-0.15 s. The target of the sensor is biped walk stabilization so that high-speed input is important. Matrix scan type circuit is connected to sensor, and the system runs 1 kHz with 14 bit resolution at 4.2 /spl times/ 7.0 mm grid for 32 /spl times/ 32 points, and the sensor size is the same as humanoid robot foot 135 /spl times/ 228 mm, The system is running high-speed because of the very thin conductive rubber and simultaneous measurement. The sensor system, a novel scan method, and evaluation results are described.

In this paper, we describe the real-time and precise self collision detection system that does not reduce the number of polygons and checks more than 100 collision pairs in real-time by using AABB based collision detection libraries. Previous researches on collision detection of humanoid robots which reduce collision pairs or simplify a shape of a robot has disadvantages such as increasing the dangerousness or decreasing range of movement. However our self collision detection system uses detailed geometric model and collision pairs as many as possible. We have experimentally evaluated collision detection libraries on a real-time self collision detection application of a humanoid robot. This experiment suggests that AABBs based method is much faster than conventional OBBs based method. Finally, we demonstrated real-time collision detection and avoidance function that automatically stops entire motion if self collision occurs using HRP2 humanoid robot.

To operate in everyday environments, robots much accomplish complex tasks following often mbiguous and uncertain instructions, mainly through advanced inference or recognition. We focus on an intelligent human-robot interaction framework that reduces the burden of the user. Robots compensate for ambiguities by active sensing and dialogue control through questions and suggestions to users. Robots also use experience to reduce the user’s burden. We propose a criterion for ambiguity evaluation of user instructions, stochastic representation of personal experiences and a dialogue control model for accomplishing tasks in complex environments. We demonstrate the feasibility of our proposal in demonstrate experiment where a robot searches for an object in disorganized work space with ambiguous instructions.

Humanoid robotics hardware and control techniques have advanced rapidly during the last five years. Presently, several companies have announced the commercial availability of various humanoid robot prototypes. In order to improve the autonomy and overall functionality of these robots, reliable sensors, safety mechanisms, and general integrated software tools and techniques are needed. We believe that the development of practical motion planning algorithms and obstacle avoidance software for humanoid robots represents an important enabling technology. This paper gives an overview of some of our recent efforts to develop motion planning methods for humanoid robots for application tasks involving navigation, object grasping and manipulation, footstep placement, and dynamically-stable full-body motions. We show experimental results obtained by implementations running within a simulation environment as well as on actual humanoid robot hardware.