Viewer,converter and preprocessor for smart machining process using an industrial robot

In this paper, viewer and converter softwares are presented for smart machining process using an industrial robot. The viewers for NC, CLS, DXF and STL files illustrate their surface representation with normal direction vectors. For example, the DXF is a data format developed by Autodesk to realize data interoperability among different makers’ CAD systems. The STL means Stereolithography which is a file format proposed by 3D Systems and recently is supported by many design tools and CAD/CAM softwares. In addition, the converters for DXF and STL files generate the corresponding CLS files with normal direction vectors for machining. Further, the proposed preprocessor allows the developed machining robot to work based on information included in STL files. The convenience and user-friendliness of the proposed integrated system are confirmed through experiments of viewing, converting and machining.     

Biodegradable polymers based on renewable resources. VI. Synthesis and biodegradability of poly(ester carbonate)s containing 1,4:3,6‐dianhydro‐D‐glucitol and sebacic acid units

Poly(ester carbonate)s with different compositions were synthesized by bulk polycondensation of 1,4:3,6‐dianhydro‐D ‐glucitol with diphenyl sebacate and diphenyl carbonate in the presence of zinc acetate as a catalyst. Most of the poly(ester carbonate)s as well as the corresponding polycarbonate were amorphous, except the poly(ester carbonate) with a small carbonate content and the corresponding polyester, which are semicrystalline. All these poly(ester carbonate)s are soluble in chloroform, pyridine, dimethylformamide, dimethyl sulfoxide, and N,N‐dimethylacetamide. Soil burial degradation tests, biochemical oxygen demand (BOD) measurements in an activated sludge, and enzymatic degradation tests indicated that these poly(ester carbonate)s are potentially biodegradable. The biodegradability was found to be maximum for the poly(ester carbonate)s with carbonate contents of 10–20 mol % and to decrease markedly for the poly(ester carbonate)s with the carbonate content above 50 mol %. The biodegradability of the poly(ester carbonate)s is discussed in terms of the crystallinity, glass transition temperature, and surface hydrophobicity of the polymer films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 872–880, 2002     

A discontinuous exponential stabilization law for an underactuated X4-AUV

In this paper, stabilization of a class of second-order nonholonomic systems for an underactuated X4-AUV is investigated. We present a model of the underactuated X4-AUV with six degrees of freedom (DOF) and four control inputs. Then, the system is written in a control-affine form by applying a partial linearization technique, and a dynamic controller based on Astolfi’s discontinuous control is derived to stabilize all states of the system to the desired equilibrium point exponentially. The present approach does not necessitate the conversion of the system model into a “chained form”, and thus does not rely on any special transformation techniques to obtain a canonical form. A simulation is conducted to demonstrate the effectiveness of the proposed controller.     

Weighted Homo-Lumo Energy Separations for the Polyene References of Fullerenes with Up to 100 Carbon Atoms

Abstract

The T value represents the HOMO-LUMO energy separation of a ?-electronic system weighted with the number of conjugated atoms. We found that this value is kept almost constant for the polyene references defined graph-theoretically for isolated-pentagon isomers of fullerenes with up to 100 carbon atoms. on this numerical basis, the T value can safely be considered as a realistic index of kinetic stability or chemical inertness for all fullerenes without abutting pentagons.     

Time‐harmonic electromagnetic field analysis in multisphere model by Gumerov's method of two scalar potentials

Time‐harmonic electromagnetic fields in multisphere models were calculated by the method of two scalar potentials proposed by Gumerov. The analyzed models were an eccentric two‐sphere model and a ten‐sphere model including the brain core and a pair of eyeballs. The applied fields were a plane wave and a dipole magnetic field, and the frequency was 1.8 or 2.0 GHz. The truncation degree p of the multipole and local expansion had values of up to 170 to 200. The peak power density on the x–y plane and the absorbed power in each tissue almost monotonically converged as p increased. These results demonstrate the usefulness of Gumerov's method. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(2): 1–10, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002–eej.21224     

Distributed parameter modeling and finite-frequency loop-shaping of electromagnetic molding machine

We derive a mathematical model for an electromagnet inside a molding machine, and propose a novel loop-shaping method of the proportional–integral (PI) controller design for the system based on the generalized KYP (GKYP) lemma. The behavior of the molding machine is difficult to capture by using finite-dimensional models owing to eddy currents spatially distributed throughout the electromagnet. To analyze fundamental properties of the system both theoretically and experimentally, we first derive a mathematical model of the machine in terms of a partial differential equation (PDE). An analysis using the PDE model shows that a low-dimensional approximation performed by standard spatial discretization results in a spillover effect, which makes the behavior of the closed-loop system oscillatory. Then, to develop an easily tunable and implementable control system, we propose a novel loop-shaping method for PI control on the basis of the GKYP lemma. In this control system design, we use multiple low-dimensional models, which work simultaneously in specified finite frequency ranges. The proposed method successfully suppresses the spillover effect despite the use of low-dimensional approximants. Finally, we show the efficiency of the proposed control design method through numerical and experimental verification and discuss a performance limitation of the PI control.     

Gas Release of SiC Implanted with Deuterium or Helium

Helium (He⁺) or Deuterium (D₂⁺) (20 keV) was implanted into polycrystalline β-SiC with an ion dose of 7.2 × 10²¹ (D or He)/m². The implanted specimens were heated at a heating rate of 10 or 20 K/min from room temperature to 1373 K, and the thermal release spectroscopic data were obtained. A sharp peak appeared at approximately 1270 K in the case of He release, and here the activation energy was estimated to be approximately 4.4 eV. Two overlapped peaks appeared at approximately 900 and 1200 K in the case of D₂ release. The shapes of spectra showed strong dependence on the heating rate.     

Fabrication of Monodispersed Barium Titanate Nanoparticles with Narrow Size Distribution

Pulsed laser ablation (PLA) was used to prepare nanoparticles of barium titanate (BaTiO₃). PLA using a titanium-rich Ba–Ti–O ceramic target in oxygen ambience at 400 Pa and following online annealing at 1073 K enabled the production of BaTiO₃ nanoparticles (BTNPs) with a perovskite structure having nearly stoichiometric composition. These nanoparticles were directly introduced into a differential mobility analyzer for size classification, leading to the production of monodispersed and nonagglomerated BTNPs with an average particle size of 13.5 nm. The size distribution of the size-classified BTNPs was found to be reasonably narrow with a geometric standard deviation of 1.07.     

High-performance object tracking and fixation with an online neural estimator.

Vision-based target tracking and fixation to keep objects that move in three dimensions in view is important for many tasks in several fields including intelligent transportation systems and robotics. Much of the visual control literature has focused on the kinematics of visual control and ignored a number of significant dynamic control issues that limit performance. In line with this, this paper presents a neural network (NN)-based binocular tracking scheme for high-performance target tracking and fixation with minimum sensory information. The procedure allows the designer to take into account the physical (Lagrangian dynamics) properties of the vision system in the control law. The design objective is to synthesize a binocular tracking controller that explicitly takes the systems dynamics into account, yet needs no knowledge of dynamic nonlinearities and joint velocity sensory information. The combined neurocontroller-observer scheme can guarantee the uniform ultimate bounds of the tracking, observer, and NN weight estimation errors under fairly general conditions on the controller-observer gains. The controller is tested and verified via simulation tests in the presence of severe target motion changes.