Time-optimal path generation for continuous and quasi-continuous path control of industrial robots

For a given continuous path, the problem of designing a time-optimal time-parametrization is considered. First, algorithms are presented which, under rather mild assumptions, yield the exact solution within two computational steps consisting of a forward and a backward computation. Then, the problem of quasi-continuous robot motion is investigated in detail. An algorithm of the same type results, but the computational burden is considerably reduced by making appropriate use of the special structure of the problem. By this, on-line use becomes feasible.Work supported by Oesterreichischer Fonds zur Foerderung der wissenschaftlichen Forschung.     

Micromagnetic simulation of current-driven domain wall propagation

We develop a method to model the interaction of currents and domain walls in a standard micromagnetic simulator. The interaction of spin-polarized currents and localized magnetic moments can be described by a current-induced effective field, which superposes to other components of the effective magnetic field. Using our method, we examine domain wall propagation in ideal, rough-surfaced and notched domain walls.     

Long-Memory Errors in Time Series Regressions with a Unit Root

This paper is concerned with estimation and inference in univariate time series regression with a unit root when the error sequence exhibits long-range temporal dependence. We consider generating mechanisms for the unit root process which include models with or without a drift term and we study the limit behavior of least squares statistics in regression models without drift and trend, with drift but no time trend, and with drift and time trend. We derive the limit distribution and rate of convergence of the ordinary least squares (OLS) estimator of the unit root, the intercept and the time trend in the three regression models and for the two different data-generating processes. The limiting distributions for the OLS estimator differ from those obtained under the hypothesis of weakly dependent errors not only in terms of the limiting process involved but also in terms of functional form. Further, we characterize the asymptotic behavior of both the t statistics for testing the unit root hypothesis and the t statistic for the intercept and time trend coefficients. We find that t ratios either diverge to infinity or collapse to zero. The limiting behavior of Phillips's Z _α and Z _t semiparametric corrections is also analyzed and found to be similar to that of standard Dickey– Fuller tests. Our results indicate that misspecification of the temporal dependence features of the error sequence produces major effects on the asymptotic distribution of estimators and t ratios and suggest that alternative approaches might be more suited to testing for a unit root in time series regression.     

Solids motion in a conical frustum-shaped high shear mixer granulator

An experimental study has been carried out on the solids motion in a conical frustum-shaped vertical high shear mixer granulator by using the positron emission particle tracking (PEPT) technique. The mixer granulator has a vertical shaft attached to which are 4 sets of impellers at different elevations. The shaft is operated at 3, 6 and 12 Hz, which correspond to the top impeller tip speed of 2.1, 4.1 and 8.3 m/s. Particles are observed to circulate in both the horizontal and vertical directions. The period of horizontal circulation is short and is in the order of seconds, whereas that of the vertical circulation takes tens of seconds and often consists of lots of higher frequency fluctuations. There is a dominant solids motion in the tangential direction at all impeller speeds with the maximum tangential velocity 2.2-5.3 times that of the maximum axial and radial velocities. The maximum values of the three velocity components increase with increasing impeller speed, but the ratios of the maximum velocity to the tip speed decreases with increasing impeller speed, suggesting a rate-dependent behaviour. The particle flow pattern shows the presence of swirling flows at a position depending on the impeller speed. The results also suggest the existence of an optimal impeller speed that gives the best macroscopic mixing characterised by the vertical solids circulation.     

Motion‐blur characterization with simulation method for mobile LCDs

Abstract— A simulation method based on measured liquid‐crystal responses and human‐vision properties was proposed to characterize the motion blur of LCDs. A perceptual experiment was implemented to validate the simulation model within different viewing conditions by changing the visual angle. The results indicate that the smaller visual angle of the mobile display has no statistic significant effect on smooth‐pursuit eye tracking when perceiving a moving block on a screen. The calculation process of quantitative metric was presented based on the measured light behavior and the simulation model. In the end, the different motion‐blur reduction approaches were evaluated for mobile LCDs.     

Novel 120‐Hz TFT‐LCD motion‐blur‐reduction technology with integrated motion‐compensated frame‐interpolation timing controller

Abstract— Samsung has developed a high‐resolution full‐HD (1920 × 1080) 120‐Hz LCD‐TV panel using a novel pixel structure and a motion‐compensated frame‐interpolation (McFi) single‐chip solution. Our latest work includes launch of a 70‐in. full‐HD panel, the world's largest LCD TV in mass production, with a 120‐Hz frame rate. A serious problem involving the charging time margin has been completely overcome through the use of a new alternative 1G‐2D pixel structure and a new driving scheme. Compared with conventional dot‐inversion driving, our new dot‐inversion method, which is a spatial averaging technique, can save power because the column drivers are operated using vertical inversion driving. In addition, McFi, which merges individual ME/MC and timing‐controller (TCON) ICs and memories, has been developed and applied in a mass‐production product for the first time ever. The McFi solution provides 120‐Hz driving with the lowest possible system cost. Motion‐picture response time (MPRT) has been reduced from 1 5 to 8 msec. Moreover, for the case of 24‐Hz film source mode, motion judder has been completely eliminated. As a result, a lineup consisting of 40‐, 46‐, 52‐, 70‐, and 82‐in. LCD‐TV panels with high quality and manufacturability has been made possible.     

冗余度柔性杆机器人自身运动消减残余振动研究

冗余自由度常被用来实现机器人躲避障碍、避免奇异位形、增加灵活性以及优化某些动力学指标等目的。本文将冗余自由度用于消减柔性杆机器人的残余振动，通过优化选择最优的自身运动以达到减振目的，模拟结果表明，这一方法可以取得很好的效果。     

A technique for motion specification in computer animation

A technique is discussed for the interactive specification and real-time evaluation of the movements of geometrical objects with several degrees of freedom. The technique is a midway between a faithful simulation of the dynamics and kinematics of the object and completely free user control, and as such it is well suited for animated drawings, for example. The method works in two steps: first, the motion of a relevant subobject (the skeleton) is specified interactively in real time. Next, the entire object is deformed and oriented in space such as to match the form of the skeleton. Depending on the complexity of the object, this second step either takes place in real time, or as a batch process. Several forms of geometrical constraints, as well as stretching and squeezing, are supported.     

Design of a radiant “Strip” heater for simulating liquid fuel flows in flame spreading

In order to create and to study the effects of liquid surface motion, a radiant strip heater which consisted of a heated rod at the focal point of a parabolic mirror was designed. Several configurations were analyzed to determine the appropriate design for a heater and it was experimentally proven that a heater with eight heated rods placed in an encasement can provide a nearly uniform heat flux on a fuel surface with magnitude varying with vertical distance. Using a heat flux gauge at various horizontal locations at a specific vertical location, the ratio of measured heat flux between the center and the outer edge of the heater was found not to exceed 1.10.     

MCDC 2805型直流电机运动控制器的原理及应用

MCDC 2805型运动控制器是专为Faulhaber集团生产的直流微电机量身定作的。它由功能强大的16位微处理器和性能卓越的数字滤波器组成。文中介绍MCDC 2805的硬件结构、外型封装、RS-232串口的功能及RS-232串口的ASCII指令及其应用。