A Quintic Spline Interpolator for Motion Command Generation of Computer-Controlled Machines

1994 ◽  
Vol 116 (1) ◽  
pp. 226-231 ◽  
Author(s):  
D. C. H. Yang ◽  
Fu-Chung Wang
Keyword(s):  
Quintic Spline ◽  
Motion Trajectories ◽  
Command Generation ◽  
Position Data ◽  
Data Points ◽  
On Line ◽  
Computer Controlled ◽  
Speed Accuracy ◽  
Linear Interpolator ◽  
Accuracy Speed

This paper presents a new method of motion command generation for computer controlled multi-axis machines. The method is based on a quintic spline interpolator (QSI) which generates motion commands to trace a set of desired discrete position data via a composite quintic spline (CQS). This CQS is nearly arc length parametrized and has second order continuous at the data points. Consequently, the generated motion trajectories are continuous in both velocity and acceleration throughout the motion. A quick motion command generation scheme is also developed. Compared to the existing linear interpolator (LI), the proposed method takes comparable execution time, but is superior in many other aspects, including position accuracy, speed smoothness, acceleration continuity, torque requirement, and jerk reduction. Compared to the existing cubic spline interpolator (CSI), the proposed method is able to maintain a similarly smooth composite profile, but better speed accuracy. On-line implementation of this interpolator is believed very promising.

A Quintic Spline Interpolator for Motion Command Generation of Computer-Controlled Machines

1992 ◽  
Author(s):  
D. C. H. Yang ◽  
Fu-Chung Wang
Keyword(s):  
Quintic Spline ◽  
Motion Trajectories ◽  
Command Generation ◽  
Position Data ◽  
Data Points ◽  
On Line ◽  
Computer Controlled ◽  
Speed Accuracy ◽  
Linear Interpolator ◽  
Accuracy Speed

Abstract This paper presents a new method of motion command generation for computer controlled multi-axis machines. The method is based on a quintic spline interpolator (QSI) which generates motion commands to trace a set of desired discrete position data via a composite quintic spline (CQS). This CQS is nearly arc length parametrized and has both tangents and curvatures continuous at the data points. Consequently, the generated motion trajectories are continuous in both velocity and acceleration throughout the motion. A quick motion command generation scheme is also developed. Compared to the existing linear interpolator (LI), the proposed method takes comparable execution time, but is superior in many other aspects, including position accuracy, speed smoothness, acceleration continuity, torque requirement and jerk reduction. Compared to the existing cubic spline interpolator (CSI), the proposed method is able to maintain a similarly smooth composite profile, but better speed accuracy. On-line implementation of this interpolator is believed very promising.

Cooperative activation in cardiac muscle: impact of sarcomere length

2002 ◽  
Vol 282 (3) ◽  
pp. H1055-H1062 ◽  
Author(s):  
David P. Dobesh ◽  
John P. Konhilas ◽  
Pieter P. de Tombe
Keyword(s):  
Sarcomere Length ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Significant Function ◽  
Cardiac Myofilament ◽  
Data Points ◽  
On Line ◽  
The Impact ◽  
Cooperative Activation ◽  
Force Relationship

This study was undertaken to determine the impact of sarcomere length (SL) on the level of cooperative activation of the cardiac myofilament at physiological [Mg2+]. Active force development was measured in skinned rat cardiac trabeculae as a function of free [Ca2+] at five SLs (1.85–2.25 μm; 1 mM free [Mg2+]; 15°C). Only muscle preparations with minimal force rundown during the entire protocol were included in the analysis (average 7.2 ± 1.7%). Median SL was measured by on-line computer video micrometry and controlled within 0.01 μm. Care was taken to ensure a sufficient number of data points in the steep portion of the [Ca2+]-force relationship at every SL to allow for accurate fit of the data to a modified Hill equation. Multiple linear regression analysis of the fit parameters revealed that both maximum, Ca2+-saturated force and Ca2+sensitivity were a significant function of SL ( P < 0.001), whereas the level of cooperativity did not depend on SL ( P = 0.2). Further analysis of the [Ca2+]-force relationships revealed a marked asymmetry that, also, was not affected by SL ( P = 0.2–0.6). Finally, we found that the level of cooperativity in isolated skinned myocardium was comparable to that reported for intact, nonskinned myocardium. Our results suggest that an increase in SL induces an increase in the Ca2+ responsiveness of the cardiac sarcomere without affecting the level of cooperativity.

Computer-Controlled X-Ray and Neutron Diffraction Experiments

1971 ◽  
Vol 15 ◽  
pp. 70-89
Author(s):  
Melvin H. Mueller
Keyword(s):  
High Speed ◽  
Storage Capacity ◽  
Time Sharing ◽  
Large Computer ◽  
X Ray ◽  
Magnetic Structures ◽  
On Line ◽  
Electronic Computers ◽  
Computer Controlled ◽  
Time Sharing System

The use of on-line computers for control and acquisition of data from x-ray and neutron diffractometers has continuously improved and expanded. Systems vary from a small 4K core computer to a time-sharing system with a medium or large computer. The choice of a single time-shared computer or an individual standalone system must be based on one's own particular environment. As large high-speed electronic computers became available, increasingly complex chemical and magnetic structures have been analysed and solved; this has created a demand for rapid, reliable, and versatile means of obtaining diffraction data. Since small computers have been developed at reduced cost and with increased storage capacity, they must be considered for use in diffraction experimentation. Therefore, in x-ray and neutron scattering, small computers are needed for data acquisition and large computers are needed for data analysis.

Computer Controlled X-Ray Diffraction Measurement of Residual Stress

1972 ◽  
Vol 16 ◽  
pp. 344-353 ◽  
Author(s):  
Carol J. Kelly ◽  
E. Eichen
Keyword(s):  
Residual Stress ◽  
Computer Control ◽  
Sample Surface ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intensity Measurements ◽  
On Line ◽  
Computer Controlled ◽  
The Difference

AbstractThe system to be described includes hardware and software for the on-line computer control of the X-ray diffraction measurement of residual stress. This determination involves accurately measuring the angles at which a back-reflection line is diffracted, first by diffracting planes parallel to the sample surface, and then by planes at an angle (ψ) to the sample surface. The residual stress is calculated from the difference in the two measured diffraetion angles. The procedure executed by the computer consists of locating the peaks, selecting three angles for collection of X-ray counts, correcting the measured counts, fitting the equi-angular intensity measurements to a three-point parabola, calculating the peak angles, calculating the residual stress from the measured angles and typing a report. This automation has eliminated the tedium of the manual X-ray data accumulation and of the residual stress calculation. The online control has also permitted improvements in the technique not practicable with the manually performed measurement of residual stress.

A Radioisotope On-Stream Analyzer for the Mining Industry

1977 ◽  
Vol 21 ◽  
pp. 193-205
Author(s):  
M. Hifetala ◽  
J. Viitanen
Keyword(s):  
Mining Industry ◽  
Sample Cell ◽  
Process Stream ◽  
X Ray ◽  
Radioisotope Source ◽  
Control Chemical ◽  
On Line ◽  
Fluorescence Radiation ◽  
Computer Controlled ◽  
Reference Samples

A distributed on-line analyzing system has been developed for automatic multielemental analysis of mineral slurries and solutions. The elements to be measured should be heavier than potassium. The system consists of measuring probes, a communication loop and a minicomputer with its peripherals. The measuring probe may either be directly immersed into the process stream or it is used with a sample cell in a by-line stream. Measuring probes are located at separate positions in the process. The measurement is based on X-ray fluorescence radiation which is excited with a sealed radioisotope source. The radiation is detected with a sealed high resolution proportional counter without filters. Spectrum stripping is based on reference samples which are measured in a computer controlled sequence in the same geometry as the sample. Thus possible instabilities in gain and resolution are under control. Chemical assays and slurry density are calculated from fluorescence and backscatter intensities. The minicomputer also controls the probes in the system and gives reports.

The Probot—an active robot for prostate resection

1997 ◽  
Vol 211 (4) ◽  
pp. 317-325 ◽  
Author(s):  
S J Harris ◽  
F Arambula-Cosio ◽  
Q Mei ◽  
R D Hibberd ◽  
B L Davies ◽  
...  
Keyword(s):  
Transurethral Resection ◽  
Human Subjects ◽  
Three Dimensional ◽  
Model Construction ◽  
Computer Interface ◽  
On Line ◽  
Computer Controlled ◽  
Line Imaging

As men age, their prostates can enlarge, causing urinary difficulty. Surgery to correct this [transurethral resection of the prostate (TURP)] is a skilled and time-consuming operation requiring many repetitive motions of a cutter. A robot has been developed to perform these motions, relieving the surgeon of much of the burden of surgery. This robot has been tried both in the laboratory and later on human subjects and has proved itself capable of performing prostate resection. The Probot system consists of on-line imaging and three-dimensional prostate model construction, an appropriate surgeon-computer interface, a counterbalanced mounting frame and a computer controlled robot.

Computer-controlled flow-injection analysis system for on-line determination of distribution ratios

1988 ◽  
Vol 60 (14) ◽  
pp. 1390-1393 ◽  
Author(s):  
Howard L. Nekimken ◽  
Barbara F. Smith ◽  
Gordon D. Jarvinen ◽  
E. J. Peterson ◽  
Marianne M. Jones
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Flow Injection Analysis System ◽  
On Line ◽  
Computer Controlled ◽  
Controlled Flow ◽  
Analysis System

An On-Line Spectrophotometer for Collection and Manipulation of Absorbance Spectra

1973 ◽  
Vol 27 (4) ◽  
pp. 279-284 ◽  
Author(s):  
Richard J. DeSa ◽  
John E. Wampler
Keyword(s):  
Wave Length ◽  
General Purpose ◽  
Wave Number ◽  
High Quality ◽  
Full Spectrum ◽  
Double Beam ◽  
Data Points ◽  
On Line ◽  
Recording Spectrophotometer ◽  
Factor Data

A uv-visible recording spectrophotometer has been developed which uses an on-line general purpose digital computer and the optical train of a conventional double beam recording spectrophotometer. The computer controls all functions of the instrument and permits the collection and manipulation of high quality absorption spectra without the use of electronic or optical correction devices. Spectra are represented by a series of up to 500 individual data points. Spectra can be manipulated in a variety of ways to meet particular experimental situations and can be displayed or plotted on an arbitrary absorbance scale. A spectrum can be added to, or substracted from, any other spectrum, differentiated, converted to log absorbance, or multiplied by an arbitrary factor. Data can be preserved on paper tape or presented graphically as a high quality labeled plot of variable size on either a wave-length or a wave number scale. The complete system can scan a full spectrum at a maximum rate of 30 nm/sec over any part of a range from 230 to 700 nm. Details of the system are presented with examples of its performance.

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