Component-based robot system design for grasping tasks

The paper presents a robot system design with highly reusable components for a component-based robot system for manipulation tasks. The robot system is designed based on the analysis of manipulation tasks using a unified modeling language use case diagram. For a service robot with locomotion and manipulation mechanisms, reusability of robot system components is improved by adopting the proposed design. Our structure consists of scenario, task, robot information management server, data analyzer, sensor hardware controller, skill, and motion hardware controller on a component-based robot system. Based on the proposed robot system, we implemented a component-based robot system and subsequently realized a grasping motion by a service robot.     

Control of chip flow with guide grooves for continuous chip disposal and chip-pulling turning

This paper presents a new chip control method with guide grooves formed on the rake face to realize continuous chip disposal and chip-pulling turning. Chips are conventionally broken using chip breakers during turning operations for disposal. However, chips of highly ductile materials or thin chips generated in finishing can not be broken easily. In order to prevent the chips from jamming up, the authors propose to continuously guide the chips away from the cutting point. Special tool tips were developed and tested for guiding the chip. Chip controllability and mechanics of the chip-guided cutting are discussed in the present research.     

Chatter Suppression with Ultrasonic Elliptical Vibration Based on Energy Principle

A new method is proposed to suppress chatter, in which the ultrasonic elliptical vibration is added on the cutting tool edge. It results in the fact that the rake face of tool is separated from the chip and the direction of the frictional force between the rake face and the chip is reversed in each cycle of elliptical vibration cutting. The experimental investigations show that the chatter can be suppressed effectively by adding ultrasonic elliptical vibration on the cutting tool edge. In order to make clear the reason of chatter suppression, the mechanism of chatter suppression is analyzed theoretically from the viewpoint of energy.     

Suppression of burrs in turning with ultrasonic elliptical vibration cutting

The approximate cutting force models in three-dimensional separating type ultrasonic elliptical vibration cutting are proposed in present paper. The theoretical models of the stresses of deformation zone on the workpiece edge in burr formation in ultrasonic elliptical vibration cutting are derived based on three-dimensional cutting model, and the reason for the burr being suppressed by applying ultrasonic elliptical vibration is clarified theoretically. Finally, the effect of ultrasonic elliptical vibration cutting on the burr is verified experimentally.     

Synthesis of multilayered composite nanotube heterostructure; SiC–SiO2, C–SiO2, and C–SiC–SiO2 nanotubes

Three types of composite nanotube heterostructures (two double-layered and one triple-layered structure) are synthesized by simple heat treatment, forming SiC–SiO₂, C–SiO₂, and C–SiC–SiO₂ composite coaxial nanotubes. These multilayered composite nanotubes consist of several components with different electrical properties, for example, metal, semiconductor, and insulator components. In particular, C–SiC–SiO₂ triple-layered nanotubes with metallic, semiconducting, and insulating layers are synthesized for the first time. These multilayered nanotubes can be expected to find applications in nanoscale heterostructure electronic and optical devices.     

Centrifuge model test on earthquake-induced differential settlement of foundation on cohesive ground

Dynamic centrifuge model test was conducted to study the earthquake-induced differential settlement of foundation on cohesive ground, and the influence of asymmetry of building was investigated. During the experiment, the overconsolidated kaolin clay ground with a three-dimensional asymmetrical structure model was shaken by a basically balanced input motion, and bender elements were used to measure shear wave velocities of model ground to reveal the soil fabric evolution during and after shaking. The test results show that, the total seismic settlement of foundation is composed of instantaneous and long-term post-earthquake settlements, and most of the differential settlement occurs immediately after the earthquake while the post-earthquake settlement is relatively uniform despite its large amplitude. The asymmetry of building affects the settlement behavior considerably. Compared with 1-or 2-dimensional structures, more evident differential settlement occurs under three-dimensional asymmetrical building during shaking, which accounts for one-half of the total seismic settlements and results in complex spatial tilting effects of foundation. Supported by the National Basic Research Program of China (“973” Project) (Grant No. 2007CB714203), the China Postdoctoral Science Foundation (Grant Nos. 20080430219, 20081476) and the Foundation for Seismological Researches, China Earthquake Administration (Grant No. 200808022)     

Proposal of ‘ImpEC (impact excitation cutting)’ for realization of high-flexibility and high-efficiency micro/nano surface texturing

In this paper, a novel micro/nano surface texturing method, namely ‘ImpEC (impact excitation cutting)’, is proposed. To machine micro/nano-textures, vibration cutting and fast tool servo have been utilized. However, the former one is limited to formation of periodical combination of sine waves since the resonance(s) of the cutting tool system is used, and the latter one is limited in terms of efficiency since it has conventionally been utilized within the bandwidth of the servo system, e.g. 3 kHz. Hence, conventional methods cannot realize high flexibility and high efficiency simultaneously. In the proposed ImpEC (impact excitation cutting), the frequencies higher than the resonant frequency are also used, and a series of impacts (pulses) are utilized to diminish the residual vibration. The proposed cutting method can create structures in a short time since the high frequency components are also used, and it can also realize high flexibility since a variety of texturing motions without residual vibrations can be triggered at any timing. The effectiveness of the proposed method is verified both analytically and experimentally.