Introduction to Simulator (Part 2)
HITACHI Analog-Hybrid Computer
Technical Information Series No.10
INTRODUCTION TO SIMULATOR
‘Part 2)
1969
Hitachi, Ltd.
rinted in
Japan
Pipe Network Simulator
In order to study new planning, improvement and supplying method of water supply pipe
and gas pipe, it is desirable that the relation among the pressure within the pipe, the amount
of flow, etc. can be readily analysed. For such a purpose, the pipe network simulator is
made. In the calculation of pressure within the pipe network and the flow, the numerical
integration method based on repetitive calculations were made. This calculation which was
done by the digital computer can also be called simulation, but in this article, an explana-
tion on exclusive simulation in which direct simulation is employed will be given.
As for the direct simulation simulator, an electrical circuit identical to the pipe network
is prepared and the current is made to correspond to the flow and the voltage is made to cor-
respond to the pressure difference. There are the following advantages in comparison with
the numerical integration.
(1) The calculation speed is fast. Calculations which obtain the stationary condition of the
current and pressure can be obtained at once. The response of each portion in relation
with the changes in load and supply conditions with the elapse of time can be found easily.
(2) The simulated circuit network is connected in the same layout (phasewise) with the actual
pipe network, so the setting of problems can be done intuitively.
(3) Since the solutions appear in parallel on the meters, the overall flow and pressure dis-
tribution can be seen at a glance. In case pilot lamps are used as the pipe elements, in
place where the loss is great, the lamps will shine brightly. Therefore, such places
can be identified at once.
(4) It is economical (Of course this depends a great deal on the precision and the scale of the
machine). From the various points mentioned above, such simulators are more suitable
if the person who uses the simulators performs various trials while observing the results,
then conducts the optimum designing, or makes the optimum supplying program.
On the other hand,
(1) Ifthe system which you wish to simulate becomes large, the simulator will also become
large, proportionally.
(2) It lacks flexibility, Needless to say, it cannot be used for purposes other than calculations
for pipe networks. Furthermore, even in case it is applied for the calculation of pipe
networks, if the accuracy or scale exceeds the limits even slightly, the problem can no
songer be analvsed.
In accition to tne above, even if the assumption is changed slightly, it will become very
aiificult to anaivse,
The above points are given as defects. In case of the digital computer, the advantages and
disadvantages are reversed. Besides the abovementioned types, hybrid systems are also
considered.
3-1. Principle of the Pipe Network
The relation between the amount of flow Q and the pressure difference H of the flow pass-
ing through the pipe can be expressed as follows:
A oO (27)
‘Sometimes for H the difference between the squares of the pressures is taken) Although n varies
according to the equations in most cases, 1.85 or 2 are used. k, is a constant which is deter-
mined by experiments. For instance, in case n= 1.85 is used for the water pipes, William-
Hagen's equation shown below is used.
ky =10.666C7185 E487 g ee teen eee (28)
where
Flow Coefficient
Diameter of Pipe
Length of Pipe
SOQ
On the other hand, as it is well known, the following re.aticn exists between the current and
the voltage in the electrical circuit network.
Ez Ro ee ee ene (29) oon
If the resistance changes with the amount of current, tne voltages at bpotn ends of the resist- fle
ance will be non-linear function of the electrical current. [fa #2113)... "on-linear resistance ne
is used, the following relation can be satisfied a.
|< (30) in
and this will be similar to the relation which exist
difference (or the difference in the squares of the pre
Biv Tum? of tiow,
Furthermore, no matter which intersection of the ftanen, there is no acculula- m
tion of the water or gas that the flowed in. Trereicr, Ra get rs amowill be zero. In
electrical circuit networks, the same equation anulie itor tir oon fis Law. The difference
that lies between the electrical circuits ang tie tite 2 wits is 11.41 ine Tormer requires a
return route. However, as shownin Fiz. 2¢, _ Pipe resistance
if the outside pressure (or standard dressur-!
of the portion used is made to corresnons wit:
the ground potential, and if the pressure -: [ oo—
the fluid is made to correspond with the el tr - |
motive force, one to one correspoingence can >: ‘ poN
made completely with electrical circuits.
\
IN N
-.2.. Simulation of Pipe Network
3.2. Operational Element of Pipe Network 13
In the abovementioned way, in order to mainta~ ue * “+ 2s rrespondence, the matter
which will become a problem from the practica. Sin intis ssatcts use for the abovementioned
non-linear resistance. As shown below, various ~materia-.+ are uses. fl:
(1) The Method Using Lamps
According to Mclloy's method which showed the first oractical success for pipe network
simulation, uses tungsten filament lamps for the Dive : s. In this method, the
change in resistance owing to temperature rise is uti: cst of each element is low, and
there is further advantage that a rough idea of the press an be obtained by observing the
brightness intensity of the lamps, as mentioned above. : ‘sacvantage of this method is that
the non-linearity is based on the physical property of the -amno. Thus, adjustments can not be
made and the accuracy will be limited. Furthermore, is necessary to prepare beforehand,
various kinds of lamps which will correspond to all sorts of pine network elements,
(2) The Method in which Two Terminal Function Generators are Used
Diode Function Generators in analog computers either combine the broken line character-
istics of the diode, and give an arbitrary non-linear characteristic between the input and output,
or based on the same concept, resistance of two terminal circuit can be made to be set as an
arbitrary function of the voltage at both ends.
mae
Fic, 21 shows this principle.
=e diode is biased in the normal direction by the battery, the state of continuity is maintained,
and the circulating current flows in the direction of the diagram. Ifthe E for the battery of
the reverse direction is determined adequately,
there will be no voltage difference between
terminal 1 and terminal 2, and they will act
merely as a resistance in case of outside circuits.
In case the voltage which is added to terminals 1
and 2 from the outside becomes large, each time
it exceeds the battery voltage, the diode connected
to that battery will enter a non-continuity state and
the total resistance will become high.
In actual practice, alternating currents are recti-
fied and used in place of the battery. Thus, itis
necessary to maintain high precision by employing
a power source stabilized by feed back, Further-
more, since this is a power sources which are
insulated for direct current shall be used,
Fig. 22 shows an example of two terminal function
Fig. 21. Example of Two Terminal
Function Generator
generator using transistors. At this time,
the saturation characteristics shown by the transistors as illustrated in Fig. 23 are utilized to
maintain the relation shown in Equation (30).
6 ’
+ _
Fig, 22. Two Terminal Function
Generator Employing
Transistor Circuit
(3) In Case Function Generators
of 4 Terminals are Used
Current
Voltage
Fig. 23. Characteristics of
Fig. 22
Fig. 24 shows a pipe network simulator used for alternating current. The current i which
flows through the pipe network is detected by current transformer, rectified, and made into
a voltage which is proportional to the current. A non-linear characteristic is formed from
this by the function generator SC which can be used for normal analog computers. Subs equent-
ly, it is modulated, shaped, then fed back to the original branch by transformer T.
A
A
lI >Re
p<] | mop
: |
El<
y
ex;
Ay 2
wo
Fy
Fig. 24, Block Diagram of Pipe Element Using
4 Terminal Function Generator
-3-
Fig. 25 shows the circuit of such function generators. All diodes used are zener diodes.
In this circuit, the voltage of D1 to Dn is too
high, and in order to lower this Eb and Dp are
connected in reverse. If suitable Zener volt-
ages are obtained, this may be omitted. As
for the method in which function generators of
(2) and (3) are used, even if battery voltage or
Zener voltage is constant, by making the re-
sistance variable, the current and the voltage
characteristics can be adjusted arbitrarily.
Furthermore, by increasing the number of
parallel circuits, the required accuracy can
be obtained. However, there is the disadvan-
tage of the circuits getting too large.
Besides the pipe network elements, load, pump
and tanks can also be connected like the actual Fig, 25. Circuit Drawing of the SC
system. The load can be simulated by the Portion (Function Generator)
resistance or constant current device. Snownin Fig, 24,
Simulation made by resistances is directly
analogues to the opening of the faucet being
fixed, and the outflow will change in accordance with the changes in pressure at both ends.
Simulation made by the constant current device is directly analogues to the user adjusting the
opening of a faucet in accordance with the amount of flow.
From the abovementioned standpoint, the latter is used a great deal. In addition to the above,
by inserting function generators having the same pressure flow characteristics as the pump,
tank, and valves at their respective positions, the pipe network containing such items can be
analysed,
The abovementioned simulators are normally used for simulation of constant state, and
mathematically speaking, it is similar to obtaining the solution of a non-linear algebraic equa-
tion, Even in case of what is called dynamic simulation, if the conditions change together with
time, in other words, in case the coefficient and constant terms of the algebraic equation
changes with time, in most cases calculations to see how the solutions follow, are made.
Problems of transient conditions in their true sense can be analysed by combining capacitors
with the abovementioned static operating elements. In such a case, good frequency character-
istics are required for the pipe network elements, and the No.2 method is the preferable
method.
As for the simulators for this type that are manufactured in Japan, those having variable func-
tional forms have several tens of pipe elements. The functional forms can be changed arbit-
rarily according to the problem. This simulators using lamps have several thousands of
lamps prepared, and suitable types are selected according to the problem.
4. Voice Simulator
Needless to say, the most natural and convenient method of exchanging information among
human beings is to emit voice and talk, and to listen to what is spoken. As a means to com-
municate between distant people, the telephone is much more conveneient than a letter or
telegrams.
Not only is it faster but the content is much more abundant,
The intention and information can be transferred much easier. Even between the computer
and the human being if information can be exchanged directly by voice, the work will be much
faster and the computer will be easier to use. The utilization value will not doubt rise con-
siderably.
Not only computers but also the other machines and equipment will increase efficiency con-
siderably if they can understand what the human being say, and also respond to it. The con-
venience in this case is beyond our imagination. Of course, there have been some machines
which can talk.
If the same sentence is to be repeated, the tape recorder can record and reproduce the voice.
If you wish to change the sentence from time to time, you can break up the sentence into
elements and combine them adequately.
In case we are informed of wrong telephone numbers or given time service over the phone, it
does not mean that a nice young lady is talking at the other end of the phone,
"The time now is....,.. " ‘That number has changed .......... Please re-dial.'' The
dotted line portion is changed, and it is a recorded tape that is giving the information.
As for more complex usage, tne sentence is broken up into words,
then the words are reassemb-ec again to form sentences and
reproduced.
In case of the stock excne
in New York, if the security dealer who
stocx value of a certain machine com-
oa 2 taiking computer by dialling
culine voice will answer
is outside wishes to know
pany, he can get the intor:
a specified number. For instance a
Vocal tract
back "........ Machineries, Onen! Quotation 83, Highest Price
85, Lowest Price 82, Turnover 7000. In order to really utilize
voice as a means for conveying intormation instead of the system
Vocal chords
.r, the voice emit-
“, and complicated Trachea
which is like cutting takes anc putting *
ting mechanism should be controlled by
voices should be synthesized. Fig. 26
In order to accomplish this, the mecranismr trem which voice is ,
emitted, and the elements whicn compos xe checked, Asa
synthesizing method basec on ia: nvbric computer
system in which the analogous avnin nvioe is contrecled by the computer output is
considered to be the common sense concent,
As for the analogous synthesizing device, there is the sp. otrum analog system (Up to quite
recently, this was called the terminal analog svst vith. VOCODER system is included
in this) which simulates the sound as a pnenomreron a? cantiguration analog system (This
used to be called the vocal tract analog) which simulates +h: ization movement of the
mouth by tracing back to the physiology and physics of v
The spectrum characteristics of the voice wave nave been
if necessary, it can be measured directly and confirmed. T
possess is abundant, and a lot of quantitative analysis cata »
hardware is also comparatively simple in case of tne spectrum an
it is more economical.
On the other hand, the research work on vocalizing organs anc vr
chiefly based on the personal views and personal observations o:
result, most descriptions are qualitative descriptions, and with
sighted research work, objective and quantitative observations b2as
movies have just begun. At present, we still lack knowledge anda
more, as for the configuration analog method, it is very complicaty¢ as mentioned later, and
there are still many technological difficulties. Therefore, the orice is very high.
However, if we take up the problem of making laws for the synthesis, it will be more sub-
stantial (i.e. The description of law will be more simple, and there will be less exceptions, )
to go back to the cause or vocal movement rather than to think in the dimension of spectrum
characteristics or phenomenon, In addition to the above, judging from the ability of synthesiz-
ing continuous vocal sounds, it may be said that the configuration analog system which has
limitations necessarily imposed on vocal waves owing to the utterance of the human beings set
into the operation of the synthesizing device, has a higher potential capacity.
Voice emitting
mechanism,
Stem,
<8 great Gial in the past and
ore, the knowledge that we
aren accumulated, The
< svstem. Consequently,
~oca. specialists. Asa
exception of a few fore-
>on X ray or X ray
itative data. Further-
(a) Spectrum Analog System
The research on synthesis based on the laws of spectrum analog system is being done at
various places in Japan such as Tohoku University, NHK General Technological Labs, Oki
Electric Co., and Tokyo University.
Among such research works, the work of Ilolmes of Great Britain on the Joint Speech Research
Unit has shown quite a success by concluding it in the form of a law,
As a synthesizing equipment, parallel spectrum analog as that shown in Fig. 27 was used, and
control was performed on the following nine parameters,
FE : Basic frequency of voiced sound source.
Ss : Selection of whether the sound is voiced or unvoiced.
BR, EB, Fi : Formant frequency from No.1 to No. 3
Ai, Az, As : Intensity of each formant component.
A: Intensity of high frequency energy.
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As an example of synthesis, "A bird in the hand is worth two in the bush" was shown in the
following three steps.
(i) The values of all control parameters
were extracted as a result of analys-
ing the live human voice, and control
and synthesis was done accordingly. Amplitude Frequency | 5
c/s
>ontrol control
(ii) The continuing time of each syllable i !
100 ~
:. a ¥ 1000
which greatly influences the natural- P,
eel :
a, oH 700 ~
F, 2400
ness, and the pitch frequency F. of
the vowel portion have been controlled
by the results obtained from the analysis +
of the live human voice. Only the con-
trol of the formant characteristics was A; I \
done in accordance with the calculations | a4 thon oOut
based on the law. A P ;
+ Fy
in accordance with the law. Although _
it is quite natural that the quaity of the - | — BPE
synthesized voice will drop in the order Nowe o + 0
of (i) (ii) and (iii), the meaning of (iii)
was quite understandable. However, it
was recognized that the naturalness was Fig. 27. Composition Drawing of
lacking. Synthesizing Unit for JSRU
(iii) The control of all parameters were done Pulse L of oo a4 3500
|
| |
F
(b) Configuration Analog System
The research work based on the configuration analog system is also being done in Japan
at the Electro Technical Lab., Meiji University, ete. Tne recent results obtained at
I are quite remarkable.
ce block diagram is shown in
The external view of the equipment is shownin Fig, 2:5, a
Fig. 29. If we give a brief explanation of the principle, +
The channel from the glottis to the lins is consiceres a
length of about 17 cm. This is simulated by seventeen
areas anda length of 1 cm each. According to the soi
sound for each round tube can be expressed by the fo-lowin
posed by an analog computing circuit shown in Fig. 30.
Read ‘distribute
MT
. ; Fig. 29 Configuration Analo
Fig. 28 Voice Synthesizing Unit ° System °
(Configuration Analog System)
an na
To
Um-il-lm o 7 Am Pm
2
m m pe*
mt m-1
where
Volume speed of air inside of the cvlinder
Sound pressure
Length of the cylinder (cm)
Density of air (g/cm)
Speed of sound (cm/sec)
Cross Section of Cylinder (cm?)
povUrycd
The cross section A will have to be controlled in
accordance with place and time, (Actually, this
is controlled by the area ratio.) The multiplier
will perform D-A conversion at the same time it
conducts multiplication. However, in order to
prevent the flick caused by the digital control Fig. 30. Basic Block Diagram
signals, the multiplier is designed for a smoother
characteristic against control signals.
5. Simulator in Relation with Medicine
It has been known from olden times that living bodies are gatherings of complex control
systems which is composed of multi-feed back loop. However, the analvsis of the system
was quite qualitative. Together with the development of the centro. theory, quantitative
analysis was begun from very simple feedback loops.
Since the control loop of the living bodies contain a number of ~ sinear elements, simula-
tion is indispensable for their analysis. The development o: simulators is being advanced for
nerve cells and certain functions of the organs.
At first, the purpose of developing such simulators was for cbtaining an auxiliary means for
studying physiology, but now some are being studied for the ceve_-opment of control equipments
for living bodies, and for engineering means. As simulators [cr living bodies, there are vari-
ous kinds such as nerve system, respiratory circulating svstem, metabolism are exactly the
same as those used for chemistry, they will be omitted mere, anc explanations shall be given
on nerve system and respiratory circulating system.
d-1. Simulator of the Nerve System
The nerve cell which composes the nerve system is composed of tne cell body, dendrite,
and axon. The axon is also called the nerve fiber, and ths end of it i= branched. The branched
portion is called synopsis and it connects with another cel body or dendrite of other nerve cells.
The information transmission of such nerve cells can be detected Dendrite
from the outside as electrical impulses. Thus signal input from
other nerve cells to the synopsis, and its relation witn the ceil
output, the signal transmission characteristics inside of nerve
fibers, etc., have been made clear, and simulators have been
proposed. In the following paragraphs examples of simulators
are shown by discriminating the former as nerve cells and the
latter as nerve fibers.
3-1-1. Cimulators for Nerve Cells
The nerve cell receives the output of other cells as input,
via the Synopsis. There are two types of inputs. One which will
excite the cell and cause output (i.e. exciting input), and another
.niehn is reverse and which has suppressive effects, Over ten
uitferent properties between the output and input have been made Fig.31 Nerve Cell
-7-
clear, Since it is very difficult to develop a simulator which can satisfy all of the conditions
simultaneously, simulators possessing the major properties have been developed.
For instance, Harmon of the Bell Telephone Labs. assumed the following properties, and
developed a simulator illustrated in Fig, 52.
(i) In case a stimulus exceeding a certain
limit is given within a limitec time,
the cell will be excited anc sen¢ our
pulsive output. No matter now long
stimulus below a certain .evel is
the cell will not become excite:
limit value will change asa
the elapsed excitation o: the cell.
(ii) In case the cells become excited, no
matter how large the stimulus is, tne
cell will not become excited Tor about
2-3 m sec as if the threshold value
has become infinite (This period if
called the period of non-response. )
(iii) In case two or more stimuli less than
the threshold value is given to one cell,
those stimuli will be added, and if the (b) Model Circuit of Nerve Cell
sum of the stimuli exceed the limit value,
the cell will be excited, Fig. 32 Simulator for Nerve Cell.
(iv) In case the suppressive synopsis is stimulated, even if the exciting synopsis is stimul-
ated at the same time, the cell will not be excited. As shown in Fig. (a) of the block
diagram, in order to obtain properties (i) and (iii) an incomplete integrator is used, and
feedback is employed for obtaining (ii). Furthermore, suppressive input is given to
obtain property (iv).
5-1-2. Nerve Fiber Simulator
The nerve fibers which transmit the output of ceils have attracted the attention of
people engaged in engineering since they possess an idealistic electrical pulse transmission
system for forming waves.
There is an excellent mathematical model of Hodgikin-Huxley for this transmission character-
istic, and Nagumo et. al. have proposed a simulator using tunnel diode as shown in Fig. 33 by
studying the above mentioned mathematical model. As shown in Fig. 34, this transmission
system has an excellent wave forming property in which the amplitude and pulse width can be
made identical. Besides the above, a large number of simulators have been proposed, but
they will be omitted here. o- t t $ °
5-2, Simulator of the Circulating System
oq Kw ©
The circulating system which is composed 7 ) +}
of the heart to send out blood, large and small
arteries, capillary tubes and veins with the
circulation of blood, metabolism of components Fig. 33 Simulator of Nerve Fiber
within the blood, and their control system. For
instance, as a Simulator for circulating dynamics, | f \
Mcleod developed one which is shown in Fig. 36.
For instance the heart is composed of left and /~— fo——~
right arteria and ventricles of the heart, and the —~
blood circulates in the order of right atrium, —— 0
right ventricle, lung, left atrium, arteries, viens, o™ @ 4 we
and right atrium. Thus, it can be expressed by the ~ I™.
block diagram shown in Fig. 35(a). The valves ~
shown in the diagram are valves to prevent backflow, Fig. 34 Output of Simulator
-8-
&*
.-
omy weg
wm
BY,
the
and they are quite indispensable.
However, on account of this, blood flow resistance will
form. The thickness of the heart muscles for the left ventricle and the right ventricle are
thicker than those of the arteria, and the compliance increase of decreases in proportion to
Thus, an electrical equivalent circuit shown in Fig. (b) can be made.
the volume.
right atrium left atrium Pr Ppa
Uright un, left
ventricle c 8 P erericle C
7 1/c
Trigeminal lung arteries Cowled : tv Er Ver pe ‘pa
Valve Valve Valve Arteries
(wv) (mv) Valve L/Rto 1/Rpa
(PV) arteries (AV) Vr Vpa
and Viens
rr “Close for atrial defect !
pecs 08)— = a
1 Pa
|
Riu Row Rps Raw Rav |
| i}
/
Cr ie T Cps Ct ~ 1/Cs (26) 1/ Sun 1/Ca Vel
; | V a? Rme
AW LS Or: , d
Py
Cc + Ge rtih
lo
Fig. 35 Simulation of the
Circulating System
Fig. 36 Simulation Circuit Diagram
of the Circulating System
Fig. 36 shows the abovementioned equivalent circuit simulated on an analog computer.
The responses of various circulating system diseases are being studied by employing this
simulator. Therefore, various functons corresponding to the various diseases are added as
shown by the dotted lines in Fig. 36.
Although there are various proposals for the control system of the circulating system also,
in this article, the writer would like to show a nerve control simulator versus heart beat
which was reported by Gardner.
In other words, heart beats originate at a portion called the trunk nodule located on the right
atrium, and the rate of stimulus is controlled by the sympathetic nerve and the vagus which
gives the input. In order to find this transmission characteristic, Gardner stimulated each
nerve of a dog and investigated the response. As a result he found that the heart beat can be
given by the following equations.
HR, + GCs )f1
HR= ———————
G(s) = CAe"TS(1+t3s)*#I/C 1+ tys)C1t+ts5s)
H(s) = BC1lt+t ys )*#*/CI+T2s8)
where
HR =: Heart beat at the time when there is no stimulus.
f,, f2: Stimulus frequency of sympathetic nerve system and the vagus system.
A, B: Non linear characteristic shown in Fig. 37.
x This term will become effective only when 60
In case the abovementioned transmission characteristics are
the stimulus frequency of the nerve system
has increased.
A (S beats/min )
simulated, relations shown in Fig. 38 can be obtained.
Although the response of this simulator is not complete, it
is very interesting because it suggests the research trend
in the future, and by the development of such independent
Simulators, the analysis of even more complex phenomenon
can be made possible.
-9-
ovat f, =15%
ou
f=)
“A”Right
sympathetic
i=]
“B” Right vagus}* —
ww
So Ss
10
0 5 10 15 20 20
frorfs(%)
Fig. 37 Static Characteristics
of Heart Beat Control
System
5.3, Simulator of the Respiratory System
The simulation of the respiratory system also consists of the intake of oxygen into the
blood, and discharging of carbon dioxide (i.e. gas exchange function), breathing dynamics of
the lung, and the control system for
the above. As an example, an ex-
planation will be made on the respi-
ratory dynamics system proposed by “-B
Yoshimoto, et. al. Function
generator
In other words, the exchange of gas
is done between the lungs and the fi
outside air via the bronchial tube S P
agus
and branch. Consequently, the [ie | Sympa thetic (
ay “ A HR, +G(S)fy
pressure of the lungs will balance vende Lead t Lead ts R=
with the inside pressure of the chest fh yon
. “A” n AA
which surrounds the lungs and the A Pt 1
: : Delay Function , :
compression force of the lungs owing tape [] generator
to its elasticity. Furthermore, the
amount of gas that will be exchanged
will be determined by the inside
pressure of the lungs and the imped- Fig. 38 Simulator of Heat Beat Control
ance of the bronchial tube and branch.
On the other hand, since it is clear that the compression force of the lungs based on their
elasticity and the impedance of the bronchial tubes are non-linear. The simulator shown in
Fig, 39 was developed under the assumption that the admittance will be proportional to the
difference between the bronchial tube branch and the inside pressure of the chest.
As shown in the drawing, this simulator consists of the left lung, right lung and the bronchial
tube,
In accordance with the change in
chest pressure caused by the
stimulus from the respiratory
control center, the change of
inside pressure in the lungs will
occur. As a result, the gas L
exchange flow amount can be d r [; sacha) tbe
obtained as an output of the ad- \ Pressure
(\——~.
mittance determining portion of O, | <br
ube
Inside pressure of the chest left lung
Inside pressure of the lung exchahge gas
left lung
<[}
All exchange gas
Insige pressure
the bronchial branch which is othe bret
determined by the Summer A and h—_—*]
the Multiplier M.
The integrated value of this
exchange gas flow will change the
lung volume and return the
inside pressure of the lungs to
the original level.
By improving this simulator
slightly, a simulator which com-
bines the breathing number and
control system are also developed. Fig. 39 Simulators for the Respiratory System
Simulators for gas exchanging
functions are also developed by Grodin but this matter will be omitted here.
NP
yy
<J]] Right lung
Right lung
Inside pressure of the lung exchange gas
Inside pressure of the chest.
9.4. Other Simulators
Besides the above mentioned simulators, there are various other simulators such as
body temperature controlling system, osmotic pressure adjustment svstem for the kidneys,
and the blood sugar controlling system.
Owing to the limit in space, such matters will be omitted. Since the functions to be simulated
in the living bodies are non-linear, the simulator is becoming an even more important tool
for the analysis of such phenomena.
A great development can be anticipated for the future of simulators.
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