Masayoshi Hashima

Satellite berthing experiment with a two-armed space robot

To study autonomous control of a space robot, the authors developed their Advanced Space Robot Testbed with Redundant Arms (ASTRA). Berthing a satellite moving in space is a difficult and dangerous task when done manually. This paper describes a robot which berthed a mockup satellite moving and rotating in zero gravity. Features of the robot include autonomous approach to a moving target satellite using visual satellite motion estimation, using real-time visual tracking control to track satellite handles with two robot arms, and grasping the satellite handles with minimum mechanical shock using a flexible wrist mechanism and impedance control. The authors ran their satellite berthing experiment on the ASTRA to check its performance.<<ETX>>

Localization and obstacle detection for robots for carrying food trays

This paper discusses a practical system which, when incorporated in an autonomous mobile robot moving indoors, can determine the position of the robot and detect obstacles so that the robot can navigate appropriately. We have developed new real-time, reliable techniques using correlation operations to achieve vision-based localization and obstacle detection. These techniques include a landmark detection technique that assures stable detection even under variable brightness and an obstacle measurement technique that combines obstacle region segmentation with stereo vision. Our experiments have proven that these techniques can make the necessary measurements in 100 ms, assure stable measurement in environments of varying brightness, and are sufficient for mobile robots.

A Thin-plate CAD Mesh Model Splitting Approach Based on Fitting Primitives

Extracting structural information from mesh models is crucial for Simulation Driven Design (SDD) in industrial applications. Focusing on thin-plate CAD mesh models (the most commonly used parts in electronic products such as PCs, mobile phones and so on), we present an algorithm based on primitive fitting for segmenting thin-plate CAD mesh models into parts of three different types, two of which are extruding surfaces and the other is a lateral surface. This method can be used for solid model reconstruction in the SDD process. Our approach involves two steps. First, a completely automatic method for accurate primitive fitting on CAD meshes is proposed based on the hierarchical primitive fitting framework. In the second step, a novel procedure is proposed for splitting thin-plate CAD mesh models by detecting parallel extruding surfaces and lateral surfaces. The method presented here has been proved to work smoothly in applications of real product design.

A stereo vision system for position measurement and recognition in an autonomous robotic system for carrying food trays

This paper describes a practical stereo vision system for position measurement and recognition in an autonomous food-tray-carrying robot. Our food tray carrying robot delivers and collects food trays in medical care facilities. The vision system must position and recognize tables and trays for the robot to manipulate the trays. We developed edge detecting techniques for the measurement of target objects that vary in terms of brightness using correlation operations. We fabricated a compact environmental perception unit using a real-time image correlation processor (the color tracking vision) and had it installed on the food carrying robot. Tray delivery and collection experiments in simulated environment show that the unit can position the tables and the food trays accurately enough to manipulate the trays in varying degrees of brightness (60 to 7200 1x) using video images from a pair of stereo cameras installed on the gripper of the manipulator.

Interactive Thermo-Fluid Simulation by Using Reduced Order Models

We present a new finite difference-based thermo-fluid simulation method by using reduced order models. Reduced order modeling technique is to project a high dimensional problem onto a lower dimensional subspace and then solve the problem in the reduced subspace. We solve the incompressible Navier-Stokes equations and the heat equation in their respective subspaces and join the two equations by projecting the advection term onto the joint reduced space. Our algorithm allows for fast thermo-fluid simulation of the large-scale computational models at a fraction of computational load. Our method shows more than one thousand times faster speed than usual mesh-based fluid simulation, while maintaining acceptable engineering accuracy. The real-time feature of our method enables interactive user interfaces for, e.g., assessing an immediate thermal field change in response to consecutive control of air-conditioning equipment in a data center.Copyright

Real-Time Deformation Simulation and a Design Support System for Wire Harnesses

The layout design for the wire harnesses cannot be performed until a mechanical prototype is completed because of the necessity to determine the route and length in consideration of deformation. This paper proposes a real-time wire harness deformation simulation method that works together with a mechanism, and a design support system that allows virtual verification of wire harness layout using a 3-D product model. Real-time deformation simulation includes mechanical simulation calculating kinematics and harness shape simulation using a Bezier curve. The design support system allows interactive verification of exact length, maximum curvature and collision by simulating the behavior of a mechanism and a wire harness.Copyright

Design and Manufacturing Methodology for Mechanical Systems Using Virtual Product Simulator

In mechanical systems development, it is well known that verification tests covering all aspects of mechanics, software, and hardware cannot be performed until a working prototype of the product is completed. As a result, serious flaws may be not discovered until the final stages of development, resulting in delays and extra work, mainly on the embedded software (known as firmware). We propose a new design and manufacturing methodology for mechanical systems that is based on a 3D real-time simulator, called “VPS” (Virtual Product Simulator). This simulator enables the development of virtual mechanical models on computers, allowing engineers to work on the model without seeing the actual device. It provides more time to thoroughly test the whole system, thereby, making the development process more efficient.Copyright

Image Compression for Remote Desktop for Engineering Cloud

With the development of the cloud computing, many services that provide a desktop environment over a network are coming into widespread use. In recent years, the demand that globalized product developments and cost reductions is increasing. This leads to a growing demand for using these services in product design and development activities, a challenge in this situation is to make 3D-CAD and CAE software available over remote desktop services of the cloud, namely Engineering Cloud. In this paper, we propose a lossy image compression method for 3D-CAD and CAE software at high compression ratio. This method extracts constant gradients by a frequency transform, which exploits the nature as artificial images in that the local variations in pixel value are constant. We demonstrate that this method achieves a 1.4 times improvement in compression ratio as compared with conventional JPEG. We also apply this method to a remote desktop system, which demonstrates that the bandwidth is reduced by 43% of JPEG case.

A Design System for 3D Bending Shape of Flexible Printed Circuit in Electronics Devices

ABSTRACTFlexible Printed Circuits (FPCs) are often used in electronics devices. It is made on a thin elastic film which is bent in the devices and mounted on circuit boards. In this paper, a system to estimate the 3D bending shape of the FPC is proposed. A 3D path of the central curve of the FPC is first designed to connect the end connectors and then its surface is generated from this curve and the 2D diagram of the FPC. We propose a method based on rectifying developable surfaces to generate the surface. A new method for preserving the curve length is also described. The prototype software is developed to demonstrate some simple design examples.

A Mass-Spring Model Approach for Interactive Simulation of Wire Harnesses

We present a method to simulate wire harnesses interactively, without ignoring physical accurateness. Our method relies on a mass-spring model, which is widely used in such areas as cloth simulation and hair simulation. Although a mass-spring model gives shapes of flexible objects with small computational cost, a considerable disparity of bending and stretching spring coefficients gives rise to serious instabilities of the differential equation to be solved. To solve this problem, we adopted a combination of successive leapfrog integrations and final fast projection to satisfy inextensibility. We applied this technique to simulate 3D industrial product models equipped with 20 to 30 wire harnesses and obtained a good operational response with the required physical accuracy.Copyright