Intelligent manipulator system with nonsymmetric and redundant master-slave

Some work is so complicated and unsteady that it is not possible to use automatic robots, such as FA robots. In such a case, a teleoperated manipulation system is applied. In this research, the authors aim at a reduction in the operator's physical and mental burdens. An artificially intelligent manipulator system has been developed with nonsymmetric and redundant master-slave. This system has five features: (1) a polar coordinates master arm; (2) a highly operational articulated slave arm with 7 degrees of freedom; (3) a nonsymmetric configuration and different degrees of freedom master-slave control; (4) an expert system; and (5) a new master-slave control motion, which makes the operator's task easier with automatic force/position control. The system was experimentally produced and its performance tested and evaluated. A qualitative evaluation was carried out by conducting a comparative test on the conventional master-slave control and the new master-slave control. It was found to be effective in reducing operating time, as well as work-induced fatigue.     

A Comprehensive Approach for Estimating Hydraulic Quantities in a Multi-branched Estuarine System

Despite many previous investigations, there is no theoretically justifiable equation to determine the freshwater discharge, tidal velocity, and salinity in a complex estuary that contains several branches. In this study, the longitudinal distributions of freshwater and salinity concentration in multi-branched estuaries are investigated using a mathematical model, considering the energy balance by frictional head loss and the salt balance by diffusion and advection in a one-dimensional steady-state condition. We attempt to obtain the time-mean freshwater discharge rate quantitatively at a junction where the main flow separates into two branches. The salinity distribution along each branch is calculated by following the dispersion coefficient equation previously proposed for a single estuary. The salinity field is divided into the near-coast region and the upstream region, because in each segment the inland velocity varies according to the tidal flux. For computing the tidal velocity, we propose the Burgers equation and the Hoph-Cole transformation. The theoretical results obtained by these equations were found to be in good agreement with a set of observed data in the Red River estuary system.     

A framework for constructing databases for supervisory control systems

This paper presents a framework for constructing databases for supervisory control systems. The proposed framework utilizes a generation-based approach and object-oriented framework libraries. In this framework, a database is designed for the target system from a design template, and the software for the database system is generated from the database design. The generated database system includes a domain-specific object system and a diagram and plant data editor, which provides effective data input functions. © 1998 Scripta Technica, Electr Eng Jpn, 123(1): 32–42, 1998     

Complex structure of triangular graphene: electronic, magnetic and electromechanical properties

We have investigated electronic and magnetic properties of graphene nanodisks (nanosize triangular graphene) as well as electromechanical properties of graphene nanojunctions. Nanodisks are nanomagnets made of graphene, which are robust against perturbation such as impurities and lattice defects, where the ferromagnetic order is assured by Lieb's theorem. We can generate a spin current by spin filter, and manipulate it by a spin valve, a spin switch and other spintronic devices made of graphene nanodisks. We have analyzed nanodisk arrays, which have multi-degenerate perfect flat bands and are ferromagnet. By connecting two triangular graphene corners, we propose a nanomechanical switch and rotator, which can detect a tiny angle rotation by measuring currents between the two corners. By making use of the strain induced Peierls transition of zigzag nanoribbons, we also propose a nanomechanical stretch sensor, in which the conductance can be switched off by a nanometer scale stretching.     

Development of high water-content cutting fluids with a new concept: Fire prevention and environmental protection

Using water-insoluble cutting fluids, which are good in lubricity but easy to mist, always risks firing and environmental problems. On the other hand, the current water-soluble coolants fail to deliver sufficient lubricity to heavy cutting applications. This study has newly proposed and developed a high water-content cutting fluid, based upon a new concept of having high lubricity despite of its water-soluble nature. As compared to the commercialized water-insoluble cutting fluid, the new cutting fluids shows a better capability of preventing oil mist and is fully applicable into cutting of various metallic materials, particularly effective in cutting of S45C and SUS304. The study also reveals a fact that a sulfur-type extreme pressure agent is the key element to enhance the cutting performance at high temperature.     

A study of the electromagnetic vibration of a capacitor induction motor caused by time-harmonic voltages

In recent years, power source voltage waveform distortion has become noticeable, as electrical appliances with rectifier circuits have become widely used. Connecting capacitor inductor motor (CRM) to such distorted supply, or controlling CRM by simple controller with a switching device (such as triacs), harmonic voltage is supplied to CRM. In that case, CRM produces electromagnetic vibrations caused by not only the fundamental voltage but also time-harmonic voltages in the distorted voltage. In addition, CRM produces electromagnetic vibration due to backward magnetic fields. Thus, it is difficult to clarify a relationship between electromagnetic vibration of CRM and harmonic voltages. In this paper, the causes of the electromagnetic vibration of CRM operating under distorted wave supply voltage are discussed. First, a general equation of dominant electromagnetic force waves is shown considering not only forward magnetic fields but also backward magnetic fields. Using a general equation, causes of dominant electromagnetic vibration can be clarified. Next, by discussing in detail some examples of the dominant vibration, the relationship between the vibration and harmonic voltages becomes evident. Furthermore, the relationship between the vibration and backward magnetic field is clarified.     

Velocity and Concentration Fields in Uniform Flow with Coarse Sands

The vertical distributions of velocity and concentration for an open-channel flow mixed with coarse sands are investigated by using a mathematical model, taking account of the momentum transfer by the turbulent motion and the sediment mass balance by the diffusion and settling in a two-dimensional steady-state condition. An attempt is made here to obtain the horizontal time-mean velocity component and the sediment concentration quantitatively at a certain depth. An examination of measured velocity profiles plotted on semilogarithmic paper leads to the conclusion that the general characteristic of the flow is greatly affected by the increasing sediment load. The vertical distribution of the time-mean velocity is calculated by following the velocity gradient equation previously proposed. The concentration field is divided into the outer region and the inner region, since in each region the fall velocity varies according to the grain Reynolds number. For computing the concentration of suspended sediment, therefore, the writer proposes two formulas derived from Fick's diffusion equation. The theoretical results obtained by the velocity and concentration equations are found to be in good agreement with a set of experimental data, for the mean diameters of the sands ranged from 940 to 1,300 μm.     

Iterative reliability-based decoding in bandwidth efficient coding schemes

In this paper, we enhance and investigate the performance of some bandwidth efficient coding schemes with iteratively decodable structure and cycles in their graph representation. In particular, we deal with bit-interleaved coded modulation and transmit diversity, using low-density parity-check and turbo codes as component codes. Simulation results show that the suboptimality of iterative decoding for moderate length codes can be at least partially compensated. Hence they allow us to also measure partially this suboptimality.