Enhanced path smoothing based on conjugate gradient descent for firefighting robots in petrochemical complexes*

The firefighting robot system (FFRS) comprises several autonomous robots that can be deployed to fire disasters in petrochemical complexes. For autonomous navigation, the path planner should consider the robot constraints and characteristics. Specifically, three requirements should be satisfied for a path to be suitable for the FFRS. First, the path must satisfy the maximum curvature constraint. Second, it must be smooth for robots to easily execute the trajectory. Third, it must allow reaching the target location in a specific heading. We propose a path planner that provides smooth paths, satisfy the maximum curvature constraint, and allows a suitable robot heading. The path smoother is based on the conjugate gradient descent, and three approaches are proposed for this path planner to meet all the FFRS requirements. The effectiveness of these approaches is qualitatively and quantitatively evaluated by examining the generated paths. Finally, the path planner is applied to an actual robot to verify the suitability of the generated paths for the FFRS, and planning is applied to another type of robot to demonstrate the wide applicability of the proposed planner.     

A Theory of Minimal 3D Point to 3D Plane Registration and Its Generalization

Registration of 3D data is a key problem in many applications in computer vision, computer graphics and robotics. This paper provides a family of minimal solutions for the 3D-to-3D registration problem in which the 3D data are represented as points and planes. Such scenarios occur frequently when a 3D sensor provides 3D points and our goal is to register them to a 3D object represented by a set of planes. In order to compute the 6 degrees-of-freedom transformation between the sensor and the object, we need at least six points on three or more planes. We systematically investigate and develop pose estimation algorithms for several configurations, including all minimal configurations, that arise from the distribution of points on planes. We also identify the degenerate configurations in such registrations. The underlying algebraic equations used in many registration problems are the same and we show that many 2D-to-3D and 3D-to-3D pose estimation/registration algorithms involving points, lines, and planes can be mapped to the proposed framework. We validate our theory in simulations as well as in three real-world applications: registration of a robotic arm with an object using a contact sensor, registration of planar city models with 3D point clouds obtained using multi-view reconstruction, and registration between depth maps generated by a Kinect sensor.     

Simulation on contact between the droplet and the slider at head-disk interface based on water-hammer pressure model

To understand the cause of read/write error due to lube accumulation, a model to simulate the slider’s response to the contact impact, which can occur between a lubricant droplet on the disk and a slider, was developed. The contact impact model is based on the water-hammer pressure model with an additional damping force, where the wave-shock pressure is assumed to function as the contact pressure, and the damping force defines the damping characteristics of the impact which are due to the lubricant’s high viscosity and squeeze between the droplet and slider contact area along the slider local velocity direction. The transient contact impact is dependent on lube droplet density, disk velocity, pitch angle of the slider, and contact area between the droplet and the slider. The measured read/write signal jump due to lube pickup can be explained by the simulation results. This modeling and simulation are helpful to us in understanding the read/write signal loss due to a lube droplet at head disk interface.     

Effects of polyglycerol esters of fatty acids and ethylene‐vinyl acetate co‐polymer on crystallization behavior of biodiesel

Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures.     

THE EXTRACTION OF NEPTUNIUM(V) BY METHYLTRIOCTYLAMMONIUM CHLORIDE AND 1-PHENYL-3-METHYL-4-BENZOYL-5-PYRAZOLONE

The synergistic effect of methyltrioctylammonium chloride (QCI) on the extraction of Np(V) by 1-phenyl-3-methyl-4-benzoyl-pyrazolone(HP) in benzene is studied over the pH range 2-6. This system extracts Np(V) better than any previously reported. The interaction of the extractants and monomer-dimer equilibria affect the distribution behavior of Np(V) in a complicated manner. Analysis of the results suggests that NpO₂ ⁺ (M⁺) is extracted as mixed dimers, (QMP₂QCl)_o and (QMP₂QP)_o.     

Observation of Magnetic Domain Structures of Magnetic Thin Films by the Lorentz Electron Microscopy

Inthisdecade,agreatmanyresearchworksonmulti-layeredmopeticthinfilmshavebeenreport6d,sincethemagneticmulti-layeredfilmsarethemosthopefulnovelmagneticmaterialsforthenextgenerationelectionicdevises,suchasgialmagneto-resiSbocesensorelemeds.hiordertOdevel...     

Grasp and Delivery for Moving Objects on Broken Lines

This paper studies the following variant of the Vehicle Routing Problem that we call the Grasp and Delivery for Moving Objects (GDMO) problem, motivated by robot navigation: The input to the problem consists of n products, each of which moves on a predefined path with a fixed constant speed, and a robot arm of capacity one. In each round, the robot arm grasps one product and then delivers it to the depot. The goal of the problem is to find a collection of tours such that the robot arm grasps and delivers as many products as possible. In this paper we prove the following results: (i) If the products move on broken lines with at least one bend, then the GDMO is MAXSNP-hard, and (ii) it can be approximated with ratio 2. However, (iii) if we impose the “straight line without bend” restriction on the motion of every product, then the GDMO becomes tractable. Y. Asahiro’s research was supported in part by Grant-in-Aid for Young Scientists 15700021, and Research on Priority Areas 16092223. E. Miyano’s research was supported in part by Grant-in-Aid for Research on Priority Areas 16092223. Presently, S. Shimoirisa is with the Software Development Engineering Department, Products Development Center, Retail Information Systems Company, Toshiba TEC Corporation.     

An investigation into the eigen-nature of cracked composite beams

It is known that the presence of cracks in composite structures introduces local flexibility associated with the changes in the dynamic characteristics of composite structures. However the nature and variations of the natural frequencies due to the presence of cracks, are still under discussion and analysis.

The present work introduces an attempt to study the variations in the eigen-nature of cracked composite beams due to different crack depths and locations. A numerical and experimental investigation has been made. The numerical finite element technique is utilized to compute the eigen pairs of laminated composite beams through several state of cracks. The model is based on elastic-plastic fracture mechanics techniques in order to consider the crack tip plasticity in the analysis. A finite element model has been developed to formulate the stiffness matrices for single edge cracked structural elements using transfer matrix theory. These matrices take into account the effects of axial, flexural and shear deformations due to crack presence. The present model has been applied to investigate the effects of state of crack, lamina code number, boundary condition on the dynamic behavior of composite beams.

The experimental tests and frequency response spectrums (FRS) is displayed on [FFT] analyzer. In experimental work the eigen pairs versus several state of cracks with various code number are measured using inductive hammering technique. The results show that the changes of the eigen parameters provide a proper indicator for detection and predication the current state of crack.