Direct Computer Control Research Articles

Routine Monitoring DCC CMM using Laser Interferometer

Manufacturing deals with the high quality product due to the accuracy which produced by measuring machines. In other case, the performance of regular diagnostic of measuring machine should be maintained to aim confidence and reliability in the measurements result. One of the equipment that can reach high accuracy is Direct Computer Control Coordinate Measuring Machine (DCC CMM). The accuracy of DCC CMM is a critical factor that affects result of product measuring. Operator need the higher accuracy machine to maintain the DCC CMM Performance and the consequent of the machine should has better accuracy than the DCC CMM accuracy it self. One of that tool is laser interferometer which has better accuracy than DCC CMM specification and produce the data and can be analyzed for DCC CMM performance. The consistent performance of the DCC CMM is constrained by the errors that brought by the machine error that occurs on a periodic basis on the account of machine usage, machine age and operating temperature. DCC CMM accuracy was compensated and improved by identifying the machine condition. This condition also applicable for predict the machine errors.

Localization in Reverberation with Cochlear Implants

Users of bilateral cochlear implants (CIs) experience difficulties localizing sounds in reverberant rooms, even in rooms where normal-hearing listeners would hardly notice the reverberation. We measured the localization ability of seven bilateral CI users listening with their own devices in anechoic space and in a simulated reverberant room. To determine factors affecting performance in reverberant space we measured the sensitivity to interaural time differences (ITDs), interaural level differences (ILDs), and forward masking in the same participants using direct computer control of the electric stimulation in their CIs. Localization performance, quantified by the coefficient of determination r 2 and the root mean squared error, was significantly worse in the reverberant room than in anechoic conditions. Localization performance in the anechoic room, expressed as r 2, was best predicted by subject’s sensitivity to ILDs. However, the decrease in localization performance caused by reverberation was better predicted by the sensitivity to envelope ITDs measured on single electrode pairs, with a correlation coefficient of 0.92. The CI users who were highly sensitive to envelope ITDs also better maintained their localization ability in reverberant space. Results in the forward masking task added only marginally to the predictions of localization performance in both environments. The results indicate that envelope ITDs provided by CI processors support localization in reverberant space. Thus, methods that improve perceptual access to envelope ITDs could help improve localization with bilateral CIs in everyday listening situations.

Modeling CMM Dynamic Measuring Error Based on the 3B-Spline Orthogonal Projection Partial Least Squares

Abstract It’s difficult to predict the dynamic error for coordinate measurement machine (CMM) by analyzing the error sources, because they are very complicated and have unknown interaction. In this paper an innovative modeling method is proposed by integrating 3B spline (3BS) transformation and orthogonal projection partial least squares (OPPLS). Three dimensional coordinates and direct computer control (DCC) parameters including positioning velocity, approaching distance and contacting velocity are used as the original independent variables of the model. The nonlinear relationship between the original independent variables and the CMM dynamic measurement errors is worked out by 3B spline transform. Then the orthogonal projection is used to build a new explanatory matrix by eliminating the components which are irrelative to the dependent variables. Finally, the operation of partial least-squares regression can be used to reduce the dimension and estimate the model parameters. With the proposed modeling method the nonlinear relationship between the independent variables and the dynamic measurement errors can be worked out without analyzing the error sources and their interactions. Besides, the problem of multi-collinearity caused by too many explanatory variables can also be overcome. The experimental results show that the mean square error of 3BS-OPPLS model is smaller than the 3B spline-partial least squares (3BS-PLS) model without the orthogonal projection, and the prediction accuracy of the model is notably improved.

Enhancement of interaural level differences improves sound localization in bimodal hearing

Users of a cochlear implant together with a contralateral hearing aid-so-called bimodal listeners-have difficulties with localizing sound sources. This is mainly due to the distortion of interaural time and level difference cues (ITD and ILD), and limited ITD sensitivity. An algorithm is presented that enhances ILD cues. Horizontal plane sound-source localization performance of six bimodal listeners was evaluated in (1) a real sound field with their clinical devices, (2) in a virtual sound field, under direct computer control, and (3) in a virtual sound field with ILD enhancement. The results in the real sound field did not differ significantly from the results in the virtual field, and ILD enhancement improved localization performance by 4°-10° absolute error, relative to a mean absolute error of 28° in the condition without ILD enhancement.

Development of an automated servo-controlled direct shear apparatus applying a constant normal stiffness condition

Correct assessment of the shear strength of rock joints is essential for several rock-engineering projects. The shear behavior of rock joints is usually investigated in the laboratory using a direct shear apparatus, wherein the forces or stresses acting normal to the direction of shear displacement are maintained constant during the shear process. However, this apparatus may be quite inappropriate for situations in which the normal stress on the joint surfaces changes considerably during the shear process. In the present study, an automated servo-controlled direct shear apparatus and computer control system have been developed to automatically accommodate the change in normal stress with dilation under the constant normal stiffness (CNS) boundary condition. A new LabVIEW-based system is used to described the performance of instrument control, data acquisition and storage operations of the new apparatus. The results of the shear tests conducted using the artificially prepared joint specimens show that the normal stiffness has a significant influence on the mechanical behavior of joints during the shear process.

Speech perception, localization, and lateralization with bilateral cochlear implants.

Five bilateral cochlear implant users were tested for their localization abilities and speech understanding in noise, for both monaural and binaural listening conditions. They also participated in lateralization tasks to assess the impact of variations in interaural time delays (ITDs) and interaural level differences (ILDs) for electrical pulse trains under direct computer control. The localization task used pink noise bursts presented from an eight-loudspeaker array spanning an arc of approximately 108 degrees in front of the listeners at ear level (0-degree elevation). Subjects showed large benefits from bilateral device use compared to either side alone. Typical root-mean-square (rms) averaged errors across all eight loudspeakers in the array were about 10 degrees for bilateral device use and ranged from 20 degrees to 60 degrees using either ear alone. Speech reception thresholds (SRTs) were measured for sentences presented from directly in front of the listeners (0 degrees) in spectrally matching speech-weighted noise at either 0 degrees, +90 degrees or -90 degrees for four subjects out of five tested who could perform the task. For noise to either side, bilateral device use showed a substantial benefit over unilateral device use when noise was ipsilateral to the unilateral device. This was primarily because of monaural head-shadow effects, which resulted in robust SRT improvements (P<0.001) of about 4 to 5 dB when ipsilateral and contralateral noise positions were compared. The additional benefit of using both ears compared to the shadowed ear (i.e., binaural unmasking) was only 1 or 2 dB and less robust (P = 0.04). Results from the lateralization studies showed consistently good sensitivity to ILDs; better than the smallest level adjustment available in the implants (0.17 dB) for some subjects. Sensitivity to ITDs was moderate on the other hand, typically of the order of 100 micros. ITD sensitivity deteriorated rapidly when stimulation rates for unmodulated pulse-trains increased above a few hundred Hz but at 800 pps showed sensitivity comparable to 50-pps pulse-trains when a 50-Hz modulation was applied. In our opinion, these results clearly demonstrate important benefits are available from bilateral implantation, both for localizing sounds (in quiet) and for listening in noise when signal and noise sources are spatially separated. The data do indicate, however, that effects of interaural timing cues are weaker than those from interaural level cues and according to our psychophysical findings rely on the availability of low-rate information below a few hundred Hz.

Theoretical evaluation of asynchronous ac dielectricnanomotors

A design for an electric nanomotor driven by acelectric fields is presented and evaluated. The motor inducestorque by means of a rotating electric field, which induces adipole in the rotor; the interactions between field and dipoleare responsible for both the generation of torque and the repulsion of the rotor, which stabilizes its position withoutcontact and removes the need for bearings. The applied electricfield is generated by square-wave pulses, allowing the directcomputer control of the device without any digital-to-analoguerequirement; the amount of torque generated can be controlledprecisely by varying the number of clock cycles between digitalstate changes. The technology is scaleable, and a motorconsisting of a rotor 1 µm long and 100 nm diameter isshown to be capable of generating approximately10-15 N m-1, equivalent to a bacterial flagellarmotor.

Production of human natural killer cells for adoptive immunotherapy using a computer-controlled stirred-tank bioreactor.

Large-scale ex vivo expansion of human natural killer (NK) cells for adoptive immunotherapy requires assurance of good manufacturing practices. However, maximal expansion of NK is also desired to facilitate clinical trials with large numbers of IL-2-activated NK (ANK). A closed-system stirred-tank bioreactor is amenable to computer control of culture variables, thereby reducing the risk of contamination. We demonstrate that NK cultured in 250-ml spinner flasks expand 2.5-fold more than NK cultured in stationary tissue culture wells. We further show that during 33 days of culture, it is feasible to control the pH between 7.0 and 7.2 and the dissolved oxygen concentration at 40% of air saturation via direct on-line computer control in a 750-ml stirred-tank bioreactor. On-line measurement of optical density by a laser turbidity sensor, as a measure of cell concentration, correlated well with actual cell count data. NK expansion in the 750-ml bioreactor was 7-fold greater than in stationary tissue culture controls and 3-fold greater than in spinner flask controls. Consumption rates of glucose and oxygen and the production rate of lactate were measured and will be used to develop a nutrient feeding strategy to convert the batch reactor experiment into closed-system fed-batch or continuous flow modes. Computer-controlled stirred-tank bioreactors may facilitate clinical trials with high-purity ANK populations for adoptive immunotherapy.

Micro-Electro-Mechanics of Ionic Polymeric Gels As Electrically Controllable Artificial Muscles

Ionic polymeric gels are three-dimensional networks of cross-linked macromlecular polyelectrolytes that swell or shrink in aqueous solutions on addition of alkali or acids, respectively. Reversible dilation and contraction of the order of more than 1000 percent have been observed in our laboratory for polyacrylonitrile (PAN) fibers. Furthermore, it has been experimentally observed that swelling and shrinking of ionic gels can also be induced electrically. Thus, direct computer control of large expansions and contractions of ionic polymeric gels by means of a voltage gradient appears to be possible. These gels possess an ionic structure in the sense that they are generally composed of a number of fixed ions (polyions) pertaining to sites of various polymer cross-links and segments and mobile ions (counter ions or unbound ions) due to the presence of a solvent which is electrolytic. Electrically-induced dynamic deformation of ionic polymeric gels such as polyacrylic acid plus sodium acrylate cross-linked with bisacrylamide (PAAM), or poly(2-acrylamido-2-methylpropanesulfonic acid) or PAMPS or various combinations of chemically-doped polyacrylic acid plus polyvinyl alcohol (PAA-PVA) can be easily observed in our laboratory. Such deformations give rise to an internal molecular network structure with bound ions (polyions) and unbound or mobile ions (counterions) when submerged in an electrolytic liquid phase. In the presence of an electric field, these ionic polymeric networks undergo substantial contraction accompanied by exudation of the liquid phase contained within the network. Under these circumstances, there are generally four competing forces acting on such ionic networks: the rubber elasticity, the polymer-liquid viscous interactions due to the motion of the liquid phase, inertial effects due to the motion of the liquid through the ionic network, and the electrophoretic interactions. These forces collectively give rise to dynamic osmotic pressure and network deformation and subsequently determine the dynamic equilibrium of such charged networks. On the other hand there are situations in which a strip of such ionic polymeric gels undergoes bending in the presence of a transverse electric field with hardly any water exudation. Under these circumstances there are generally three competing forces acting on the gel polymer network: the rubber elasticity, the polymer-polymer affinity and the ion pressure. These forces collectively create the osmotic pressure which determines the equilibrium state of the gel. The competition between these forces changes the osmotic pressure and produces the volume change or deformation. Rubber elasticity tends to shrink the gel under tension and expand it under compression. Polymer-polymer affinity depends on the electrical attraction between the polymer and the solvent. Ion pressure is the force exerted by the motion of the cations or anions within the gel network. Ions enter the gel attracted by the opposite charges on the polymer chain while their random motions tend to expand the gel like an ionic (Fermionic) gas. Two mechanisms are presented for the reversible nonhomogeneous large deformations and in particular contraction/expansion with water exudation as well as bending of strips of ionic polymeric gels in the presence of an electric field. An analytical model is first presented for the dynamics of contraction of ionic polymeric gels with liquid exudation in the presence of an electrical field. The proposed model considers the dynamic balance between the internal forces during the contraction. These forces are assumed to be due to the viscous effects caused by the motion of the liquid, the inertial forces due to the motion of the liquid in and out of the network, and the electrophoretic forces due to the motion of the charged ions in the solvent as it exudes from the ionic polymeric gel network. The effects of rubber elasticity of the network as well as ion-ion interactions have been assumed negligible in this case compared with the inertial, viscous and electrophoretic effects. The governing equations, thus obtained are then solved exactly for the velocity of liquid exudation from within the network as a function of time and radial distance in cylindrical samples. The relative weight of the gel sample is then related to this velocity by an integral equation. This integral equation is then numerically solved to obtain a relationship between the amount of contraction as a function of time, electric field strength and other pertinent material and geometrical parameters. The results of the numerical simulations are compared with some experiment results on PAMPS contractile fibers and satisfactory agreements are observed. Next, the case of electrically-induced bending of strips of ionic polymeric gels is considered. Exact expressions are given relating the deformation characteristics of the gel to the electric field strength or voltage gradient, gel dimensions and other physical parameters such as the resistance and the capacitance of the gel strip. It is concluded that direct voltage control of such nonhomogeneous large deformations in ionic polymeric gels is possible.

Continuum electromechanics of ionic polymeric gels as artificial muscles for robotic applications

A continuum electromechanical theory is presented for the dynamic deformation of ionic polymeric gels in the presence of an imposed electric field. The proposed theory is based on some recent experimental results for the deformation of ionic polymeric gels and in particular polyacrylic acid plus sodium acrylate cross-linked with bisacrylamide (PAAM). The proposed model takes into account the electro-osmosis, electrophoresis and ionic diffusion of various species. It further considers the spatial distributions of cations and anions within the gel network before and after the application of an electric field. The model derives exact expressions relating the deformation characteristics of the gel as a function of electric field strength or voltage gradient, gel dimensions and gel physical parameters. Direct electrical and computer control of the expansion and contraction of these polymeric ionic gels is possible because ionic polymeric gels are electromechanical in nature.

A direct computer control concept for mammalian cell fermentation processes

In the last 10 years, new assignments and the special demands of mammalian cells to the culture conditions caused the development of complex small scale fermentation setups. The use of continuous fermentation and cell retention devices requires appropriate process control systems. An arrangement for control and data-acquisition of complex laboratory-scale bioreactors is presented. The fundamental idea was the usage of a standard personal computer, which is connected to pumps, valves and sensors via ADA-transformation. The possibility of free programming allowed the development of user-oriented software, especially designed for the far-reaching requirements of a university laboratory in the field of animal cell culture. Control of aeration, pumps, data-acquisition and data-storage are combined within one program, which allows the automation of standard operations like measurement of kLa- or OTR-values. Pump control algorithms for all common fermentation strategies (batch, fed batch, chemostat, perfusion) are included and can be selected any time during cultivation. Oxygen partial pressure and pH are controlled via direct digital control (ddc), providing simple adaption of control parameters and set points to current fermentation conditions.

Enhanced Industrial Bioprocess Monitoring through Artificial Neural Networks

This paper demonstrates some of the industrial benefits to be gained by having a representative bioprocess model in the form of an artificial neural network. On-line estimation of fermentation process conditions is one area where industrial benefits could be found. Data from two industrial bioprocesses are used to highlight artificial neural network application to provide operators with fermentation state information. The need to achieve high levels of estimation robustness in the face of process faults is critical. Rapid model development enables multiple estimation schemes to be formulated in order to enhance robustness. Again data from the industrial systems serve to demonstrate robust estimator performance when process instrumentation faults occur. Finally, with an accurate bioprocess model available, the system knowledge can be used for control design. That is operators could be advised to make feed changes (or direct computer control implemented) in order to regulate the bioprocess at its ‘optimal’ conditions.

Reactor Operations: The Role for Computers

Although computers are being applied to reactor operations assistance, there is, as yet, very little U.S. experience in direct computer control of reactors. Given the trend toward increasing computer applications, there is a clear need for a systems analysis approach to understanding their role. This paper discusses the potential for computers in reactor operations, the factors that support their introduction, and some of the barriers that exist to increased use. Of particular interest are opportunities for computer driven graphic displays to improve the safety and economics of reactor operations, and associated challenging human factor issues. A Mitre project which explores in a preliminary fashion the value of interactive displays of current reactor thermal conditions (power shape parameters) to control room staff is discussed by way of an illustration. The paper concludes with an identification of critical issues which must be resolved as computer aided decision making in support of safe nuclear power plant operations is developed.

Production section control by transport device with computer control

The paper presents results of research and achievements of the OBR Tekoma Poland in the field of direct computer control of devices and concerns the service of a production cell by control of the transport means included in it. The transport means—called UTM—is a “cran” with an industrial robot, coupled with a minicomputer by its control system and microprocessor system of the CAMAC type. The system is designed to serve a production cell of nest or division type by the following methods. 1. (a) Control of higher order according to requirements of the supersystem, i.e. executory planning, balancing of accounts and management. These functions are executed by computer. 2. (b) Control of lower order, i.e. inside the production cell, by assignment of task to particular stands, control of transport, compensation of interferences. It may be executed both by computer and microprocessor systems depending on the division of tasks adopted. The subject matter of the present paper comprises just the problems connected with internal control and particularly with division of tasks and operation of transport means. The system is very versatile, which enables one to use many methods of transport of goods (containers, pallets, as single items or portion of goods) as well as many ways of delivery (on a storage area, to the operation area of machine or robot). The system can be applied in almost all types of division as well as in small plants.

Two Dimensional Tracing and Measurement Using Touch Trigger Probes

Summary The coordinate measuring machine (CMM) has been an important advance in automating the inspection process. Future cost reductions in metrology and operating flexibility require that CMM's be operated using extensive software packages and direct computer control. A new level of automatic measurement has been developed using commercially available touch trigger probes as self-guiding feedback control sensors for part search and measurement data collection. In the scheme developed, a touch trigger probe provides sensory input into a microprocessor based, multi-axis control system that guides the probe along the contour of an unknown part. The microprocessor detects the instant when contact between the probe and the part is made, reads the coordinates of the probe, and calculates guidance commands and the point of contact in real time. This paper presents a discussion of the tracing control and measurement theory for determining points of contact on two-dimensional part geometries using a touch trigger probe.

Distributed Control Systems For Desalination

Historically, desalination applications have not utilized direct computer control due to the relative simplicity of the typical desalination control systems, the cost of direct computer control and the heretofore sophisticated operation and maintenance procedures required to implement a direct computer controlled system. As the size of desalination plants has increased for facilities in the Middle Eastern countries, the need for energy management and data acquisition have appeared in the form of ancillary computer systems in addition to the standard analog control system for the facility. The presentation will provide an overview of typical Distributed Control systems which have become more readily available in recent years. Emphasis is placed on the steps which have been taken by various manufacturers to simplify the implementation, operation and maintenance of currently available systems and the importance of monitoring significant process variables which affect operating efficiency and the physical condition of the plant.

Emission Computed Tomography Simulator

We have designed and built a system to simulate emission computed tomography (ECT) devices and measure physical parameters of the component parts in such systems. It consists of a heavy duty X, Y, Z, ? scanning table under computer control through CAMAC with modular NIM electronics for signal processing. The modular approach allows ready reconfigurations of detectors and lead shielding to test new design concepts. Direct computer control allows simulation of complex scanning motions and detector geometries by motion of the object rather than the detectors as well as ready capability in data analysis. A study is presented in which the simulator shows a significant increase in signal to noise ratio in a commercial tomograph by small changes in lead shield geometry.

Efficient Digital Computer Simulation of a Direct Digital Control Loop

Direct digital computer control applied to process plant constitutes a class of simulation problems for which the hybrid computer is a natural simulation tool. Interactive digital computing via graphics VDU's has lessened many of the advantages formerly enjoyed by hybrid computation, but the digital simulation of sampled-data systems has its own special problems to be overcome. In this paper, the simulation model used as an example, highlights the discontinuity problems of sampled-data systems, and different methods are compared for minimising the effect, of such discontinuities on the speed of numerical integration.

The digital control of D.C. power sources

Abstract The methods for controlling the voltage of D.C. power sources manually through a keyboard or directly from magnetic tape or direct computer control have been developed. Circuit operations of two different types of digitally controlled power supply, the series transistor and the SCR phase control, are discussed in detail and actual circuitry of both types have been implemented. Experimental results show the successful operation of these circuits.

Thyristor power source for magnetic field control via direct digital computer control

Electrical Engineering in JapanVolume 98, Issue 3 p. 90-97 Article Thyristor power source for magnetic field control via direct digital computer control Isao Takahashi, Isao Takahashi Technological University of NagaokaSearch for more papers by this author Isao Takahashi, Isao Takahashi Technological University of NagaokaSearch for more papers by this author First published: 1978 https://doi.org/10.1002/eej.4390980313AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume98, Issue31978Pages 90-97 RelatedInformation