United States Patent 6,240,435
Sibeykin May 29, 2001
Method and device of determination of an input signal which changes in time
Abstract
A method of determination an input signal changed in time and its integral value has the steps of integrating an input signal to a given value of an integration result for a final point, and performing calculations also for a plurality of intermediate points.
Inventors: Sibeykin; Sergei (Brooklyn, NY)
Appl. No.: 084340
Filed: May 26, 1998
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Current U.S. Class: 708/444 ; 702/142
Current International Class:
G05B
23/02 (20060101)
Field of Search: 708/200,433,444,290
702/141,142,144,146,147
References Cited
U.S.
Patent Documents
4030038 June 1977 Daniel et al.
5031134 July 1991 Kaplan et al.
5490067 February 1996 Teguri et al.
5790442 August 1998 Ninomiya et al.
Primary Examiner: Ngo; Chuong Dinh
Attorney, Agent or Firm: Zborovsky;
I.
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Claims
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What is claimed is:
1. A device for determination an input signal which changes in time and at its
integral value containing n reference signals, comprising a multi-position
switch through which the reference signals and the input signal are supplied to
a convertor analog-frequency, a key, a counter; a unit of registration of
reference signals; a memory unit; an arithmetic-logical unit; a register of
expected integral value of the input signal; a digital comparator; arranged so
that outputs of the counter are connected to inputs of the memory unit and unit
of registration of the reference signals, outputs of the memory unit and the
unit of registration of reference signals are connected to inputs of the
arithmetic logical unit, digital outputs of the arithmetic logical units are
connected with input of the memory block and the register of expected integral
value of input signal, control outputs of the arithmetic logical unit are
connected with control inputs of the key and multi-position switch, inputs of
the digital comparator are connected to outputs of the counter and the register
of the expected integral value of input signal, in which the arithmetic logical
unit write a code equal to a sum of products of every time interval and
frequency of the convertor analog-frequency, corresponding to the reference
signal wherein the every time interval are obtained from an n equation system
in accordance with power m in which a left part of each equation in a sum of
products of the time interval T.sub.1 by the corresponding reference signal in
the power m and a right side of each equation is a product of time of determination
of the input signal by its initial moment of the power m, when, wherein m
changes from one equation to another equation in a sequence 0, 1, . . . n-1 and
the digital comparator fixes reaching by an integral value or the input signal
of a value which is equal to a sum of the products of the time interval by the
corresponding value of the reference signal.
2. A method of determination an input signal changed in time and its integrated
value, comprising the steps of integrating to the given magnitude n reference
signals which have a same nature as the input signal, the times interval of the
reference signals are determined from conditions of equality the product time
of determination of an input signal by its initial moment power m=0,1 . . . n-1
and the sum of products the time interval of a every reference signal by its
value in a power m; integrating an actual input signal over time; and
determining the reaching of a given magnitude by an integrated value of the
input signal by coincidence of a result of the integrating of n reference
signals and a result of the integrating of the actual input signal.
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Description
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BACKGROUND
OF THE INVENTION
Sensors convert nonelectrical physical or chemical quantities into electrical
signals. The behavior of semiconductor sensor devices is modeled, under a
series of assumptions, by a system of nonlinear partial differential equations
and associated boundary and input value conditions. For such sensors, it is
essential to solve numerically at least some of the equations in order to
obtain a meaningful result describing environmental conditions encountered by
the sensor. Mechanical sensors also suffer from some of the same issues
relating to nonlinearity and associated boundary and initial value
considerations.
When the desired result is determined by the integration of sensor output over
time, errors of bias scale, and nonlinearity occur. Mathematical algorithms are
used to improve the accuracy of the result by correcting for such errors of
bias, scale and nonlinearity.
The present invention relates to methods and devices of determination of an
input signal which changes in time as well as of its integral value.
Methods are known of the above mentioned general type and disclosed for example
in Inventor's Certificates of the USSR 1,453,418 and 1,541,635. In accordance
with the method and device disclosed in these references, integration is
performed to a given value of the integration result. This objective is
presented for example in inertia systems of targeting, for turning off an
engine when a rocket reaches a desired speed Vr. The input signal in
this case is an acceleration which is measured by accelerometer, and its
inaccuracies are a main source of error of the system as a whole. The device
includes a convertor 1 for a frequency of pulse sequence, a frequency
multiplier 2, an integrator or pulse counter 3, a source of reference signals
4, keys 5 and a control device 7. A code corresponding to a desired value of
speed is introduced into the pulse counter by integration of reference signals
(accelerations) during a time corresponding time interval. The values of the
reference signals can be obtained by turning a sensitivity axis of the
accelerometer relative to a local vertical. Then, during measurements of the
input signal which is the acceleration during a flight, an inverse integration
is performed. In other words, the pulses from the convertor, multiplied many
times by the frequency multiplier are deducted in the counter from the code
obtained during the time of direct integration when the counter was operating
for addition of the reference signals. A system of equations was used to
determine the reference signals and time intervals. The nature of change of the
input signal was approximately known beforehand, and therefore an initial
moment of the input signal was calculated. Zeroing of the pulse counter is a
signal that the speed reached the desired value. The above described method has
a high accuracy. However, it has some disadvantages, namely the fact that the
high accuracy is guaranteed in only one point and not along the whole scale of
speed changes. This values must be known in order to determine of the location
of a rocket. The known method and device are not always technically
implementable since it is necessary that one reference signal is greater and
the other is smaller than an average value of the input signal. However, the
acceleration can reach a few g while on the ground during giving of the
reference signals not always there is a standard of acceleration more than 1 g.
SUMMARY OF THE INVENTION
Accordingly, it is an object of present invention to provide a method and
device which eliminates the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent
hereinafter, one feature of present invention resides, briefly stated, in a
method of determination of an input signal changing in time, in which
conversions which were performed for a final point in accordance with a known
algorithm disclosed in the prior art, is also performed for final point tn
for intermediate t1, t2, tk in accordance with
a modified algorithm, so that it is possible to use not reference signals which
are required by change curve of a changing acceleration, but reference signals
which are available or in other words can be less than 1 g. The desired
movement parameters are determined during the flight, and therefore a deviation
of the acceleration curve from an expected acceleration curve does not reduce
the accuracy.
In accordance with another feature of the present invention the device is
provided with means for performing the above mentioned conversions for
intermediate points as well.
The novel features which are considered as characteristic for the present
invention are set forth in particular in the appended claims. The invention
itself, however, both as to its construction and its method of operation,
together with additional objects and advantages thereof, will be best
understood from the following description of specific embodiments when read in
connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view showing a device for determination of an input signal which
changes in time in accordance with known method;
FIG. 2 shows a linear increase in input signals and an adjustment in the
reference signals using the known method;
FIG. 3 graphically shows a changing speed over time where:
curve 1--actual speed
curve 2--reading of speed without correction
curve 3--reading of the speed using the known method, where the reference
signals are introduced for the moment in time (tn);
