Smoking machine

A method and apparatus for automated smoking to replicate a predetermined draw profile of a smoking article is disclosed. In preferred embodiments, the smoking apparatus is digitally controlled and includes simulated flexible lips which are closed during puff phases of a recorded draw profile and which are open during smolder phases of a recorded draw profile. The apparatus can also include an automatically acting lighter and an improved control system for a human mimic smoking machine.

FIELD OF THE INVENTION 
The invention relates to an automated smoking method and apparatus, i.e., 
smoking article testing machine. More specifically, the invention relates 
to a smoking machine capable of accurately reproducing a predetermined 
draw profile of a smoking article, including non-repetitive and complex 
draw profiles such as human draw profiles of a cigarette. 
BACKGROUND OF THE INVENTION 
Smoking machines are used in connection with the tobacco industry to 
determine FTC tar and nicotine values of various cigarettes when smoked 
according to certain standard test conditions. The smoking machine 
provides for the collection of various substances contained in cigarette 
smoke. The substances are later fed to an analysis stage. 
It is sometimes desirable to determine the performance of various 
cigarettes when smoked according to non-standard conditions. In this 
regard, many commercially available smoking machines are meant to measure 
smoking for specific draw profiles and adjustment is difficult. Moreover, 
motor-driven multiport machines are often incapable of reproducing some 
extreme profiles due to the inability of large motors to change speeds 
rapidly enough. In the extreme case, it is sometimes desirable to 
replicate accurately the recorded draw profile of a human test subject. 
Actual human puff profiles represented by a recorded pressure differential 
as a function of time can be measured as a test subject smokes a 
cigarette. Essentially, the cigarette is smoked through a tube having a 
constriction at its intermediate point. The differential between the 
upstream and downstream pressure can be measured via transducers and this 
pressure differential recorded digitally as a function of time to provide 
a puff profile including puff phases wherein the cigarette is being 
inhaled, and pause or smolder phases wherein the cigarette is not being 
inhaled. 
Equipment for receiving the recorded puff profiles and simulating or 
mimicking the recorded human smoking behavior on a smoking machine has 
been described in SMOKING BEHAVIOR by Raymond E. Thornton, Churchill 
Livington Publishers, 1978, pp. 277-288. The puff profile is converted 
into an analog signal, which in turn, controls an analog valve between a 
vacuum chamber and a cigarette, the valves opening or closing more or less 
depending on the particular values of the recorded draw profile. 
U.S. Pat. No. 4,365,640 describes a smoking machine capable of simulating 
human smoking, based on a recorded draw profile by a different control 
scheme. A step motor controls the operation of a vacuum cylinder. The 
stepping motor is controlled by a control circuit which converts an analog 
signal corresponding to a human draw profile into control signals for the 
stepping motor. Valves located between the cigarette and vacuum cylinder 
are also controlled by the control circuit to allow smoke collected in the 
vacuum cylinder to be exhaled during the smolder phases of the draw 
profile. A valved bypass is located between the cigarettes and Cambridge 
filter pads which collect FTC tar and nicotine. During the puffing phase, 
these valves are closed so that smoke from the cigarettes passes through 
the filter pads and into the vacuum chamber. During the smolder phase, 
these valves are opened to communication with the atmosphere to simulate a 
condition in which the smoker takes the cigarette out of the mouth. The 
control circuit includes provision for a delay between the inhale cycle 
and the exhale cycle in order to allow more accurate reproduction of 
"double draw" puffs. D.E. No. 3236593 discloses a smoking machine having a 
movable element between the smoking article and the vacuum source. The 
magnitude of inhalation cycle can be controlled by positioning of the 
movable element or valve. 
The known programmable smoking machines such as those described above are 
dependent on motor speed changes for reproduction of a puff profile. 
Inertial, mechanical, electrical and magnetic resistance to speed changes 
result in inherent difficulties in accurately duplicating puff profiles, 
particularly with respect to rapidly changing portions thereof. In 
addition, known control systems for such smoking machines suffer various 
drawbacks, including ease of modification, accuracy of control and the 
like. Further, methods used by such machines to duplicate recorded draw 
profiles do not always accurately reproduce the physical smoking 
conditions of the recorded draw profile. In addition, use of some 
motor-driven systems involves inherent capacity or accuracy limitations in 
that the number of ports, i.e., the number of cigarettes which can be 
smoked simultaneously, must be limited or accuracy must be sacrificed. 
SUMMARY OF THE INVENTION 
The invention provides improved apparatus, control systems and methods for 
machine reproduction of predetermined draw profiles, including mimic of 
experimentally recorded draw profiles. 
In one aspect, the invention provides a smoking machine having a suction 
means for drawing smoke through a smoking article together with a control 
means for the suction means in which the control means includes: (i) 
storage for storing data representative of a predetermined draw profile of 
a smoking article which includes puff and smolder phases; and (ii) means 
for producing digital control signals for controlling the operation of the 
suction means to digitally mimic the predetermined draw profile. 
Advantageously, the suction means are piston and cylinder means and the 
apparatus includes means responsive to the digital control signals for 
positioning the piston at a predetermined location in the cylinder as 
dictated by each of the digital control signals. 
In another aspect, the invention provides a hydraulically actuated 
automated smoking machine, advantageously a multiport smoking machine. A 
hydraulic ram controls the piston movement of one or more ports on the 
single or multiport apparatus, respectively. Control means provide 
movement of the hydraulic ram according to a predetermined pattern. 
Modification of the system operation is easily effected, i.e., without 
cumbersome mechanical adjustment, simply by changing control signals which 
control the hydraulic ram. The hydraulic ram can readily supply sufficient 
power to actuate many smoking port piston and cylinder means. 
Additionally, movement of the hydraulic ram can readily be varied with 
minimal magnetic and electrical resistance. 
In addition, the invention provides a smoking machine for smoking a smoking 
article according to a predetermined draw profile, including puff and 
smolder phases, which includes control means, suction means responsive to 
the control means, and support means coupled to the suction means for 
supporting the smokable object. The support means includes simulated 
flexible lip means having closed and open configurations. In the closed 
configuration, the simulated lips grasp the smoking article's mouth end 
periphery in an airtight relationship. In the open configuration, the lips 
surround the smoking article's mouthend periphery in a non-airtight 
relationship. The lips are responsive to the control means for operation 
in the closed configuration during the puff phases of the predetermined 
draw profile and for operation in the open configuration during smolder 
phase of the recorded draw profile. 
Control embodiments of the invention are directed to a method and system 
for operating a smoking machine. The control system includes storage for 
storing data representative of a measured draw profile of a smoking 
article including puff and smolder phases. Suction signals are generated 
as a function of the puff phases of the draw profile. Wait signals are 
generated corresponding to a portion of the smolder phases. The system 
determines whether the length of a smolder phase is greater than a 
predetermined value and generates exhale, i.e., exhaust signals when 
smolder phase length exceeds the predetermined value. Open- and closed-to 
atmosphere signals, e.g., open lips and closed lips signals, are generated 
for the smolder and puff phases, respectively. Wait signals are generated 
for maintaining the smoking article in the closed to atmosphere 
configuration during a discrete time period after the end of each puff 
phase to allow for puff decay, that is, time for the moving smoke to reach 
substantial equilibrium or quiescence. 
In preferred embodiments of the invention wherein the inhaling means is a 
vacuum cylinder, i.e., piston and cylinder, controlled by a hydraulically 
operated ram, it has been found that the hydraulic system can readily and 
accurately reproduce rapid changes in puff profile. Other preferred 
aspects of the invention include automatically acting lighters for 
lighting cigarettes during operation of the smoking machine. The control 
system provides engagement of the automatic lighter with the smoking 
article during a plurality of lighting puffs according to information 
recorded in or derived from a measured draw profile. The control system 
can also provide abort signals causing termination of the smoking 
machine's operation when the system determines that the value of an inhale 
signal is greater than a predetermined value. For example, in a preferred 
embodiment an abort signal is generated when an inhale signal, 
representing a location for the piston in the vacuum cylinder, represents 
a location beyond the stroke of the piston within the vacuum cylinder. 
Preferably, the control of the smoking machine is carried out by a 
programmed computer.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Apparatus 
FIG. 1 is a top perspective view of a preferred apparatus embodiment of the 
invention. A single smoking position 1 is illustrated for simplicity. 
However, nine other smoking positions indicated by radial lines 3-19 are 
preferably included in the apparatus. In general, the system comprises a 
plurality of cigarette smoking positions 1, which is also shown in FIG. 3. 
The system is preferably controlled by a programmed computer 23 which 
connects to input output interface 25, which in turn is connected to relay 
and counter 27. A hydraulically operated ram 29 drives a plurality of 
vacuum cylinders 31. Hydraulic ram 29 is connected via hydraulic fluid 
line 33 and hydraulic fluid line 35 to computer controlled valve 37. Valve 
37 is connected to a pump means (not shown) via hydraulic input line 39 
and output line 41. 
With reference to FIG. 2, a smoking article, 41 is supported by support 
means 43 such that the mouthend of the smoking article is retained within 
flexible lip means 45. Cambridge filter pad holder 47 is located between 
the smoking article and electric solenoid three-way valve 49 which 
includes an exhaust port 51 and a communication channel 53 to vacuum 
cylinder 55, best shown in FIG. 3. With reference to FIG. 3, a 
pneumatically operated automatic lighter is connected via pneumatic supply 
and return lines 57 and 59, respectively to manifold 61 (FIG. 1). Lighter 
63 connects via electrical cable 65 to interface 25 (FIG. 1). A pneumatic 
piston 67 and cylinder 69 cooperate to cause lighter arm 71 to pivot about 
point 73 in the direction indicated by arrow 75 from the retracted 
position shown in FIG. 3 to an engagement position wherein the lighter 63 
is axially aligned with smoking article 41 as shown in FIG. 2. The 
automatic lighter is supported upon a support 77 which, in turn, is 
slidably mounted upon support 79. In the engagement position, i.e., when 
piston 67 is fully extended, support 77 can be moved in the direction 
indicated by arrow 80 manually or by automatic means so that lighter 63 
engages the tip of smoking article 41. Support 77 includes a spring-loaded 
friction device generally at the location indicated by arrow 81 so that 
when moved, support 77 will remain at the new location. This "sets" the 
lighter position so that it will automatically light the smoking article 
when the lighter receives "engage" and "lighter on" signals from the 
system control. 
FIGS. 4 and 4A illustrate the flexible simulated lips and support means 
according to the present invention. A tubular support 101 is lined with a 
flexible plastic liner 103 such that the ends 105 of the liner are rolled 
back over the ends 107 of tube 101. A pneumatic supply line 109 
communicates with the space 111 between the liner and the interior of the 
tubular support. At ambient air pressure, the flexible liner or lips 103 
grasps the mouthend 113 of the smoking article in an airtight 
relationship. When vacuum is applied via line 109, the flexible liner 
clings to the sides of the tubular support so that the mouthend of smoking 
article can communicate via air channels 121 with the surrounding 
atmosphere. Support retaining means 123 maintains smoking article within 
the flexible simulated lips while the flexible lips are in the open 
position as shown in FIG. 4A. Tubular support 101 including air supply 
line 109 is commercially available from Cigarette Components Limited, 
Flexible liner 109 is normally constructed from Penrose Surgical Drain 
Tubing. As used in the past, such supports and liners are used in 
connection with automatic smoking machines to open the lips prior to 
smoking of the smoking article and the lips remained closed throughout the 
smoking thereof. It will be recognized that by making the tubular support 
101 substantially larger, the lips can be caused to close, as shown in 
FIG. 4, via pressure supplied through line 109. 
With reference again to FIG. 1, the operation of pneumatic supply for the 
automatic lighter is controlled by electric valve 131 so that air is 
supplied via manifold 61 according to control signals sent to valve 131. 
Similarly, a second manifold and electric valve control pneumatic supply 
to the flexible lips according to predetermined control signals. 
FIG. 5 illustrates operation of the hydraulic system for operating vacuum 
cylinder 55. A plurality of vacuum cylinders 55 are connected to a fixedly 
mounted upper plate 133. The pistons of the vacuum cylinders 135 are 
connected to a slidably mounted lower plate 137 so that movement of the 
lower plate in turn moves the pistons within vacuum cylinders 55. The 
movement of the lower plate is controlled by hydraulic ram 29. Thus, when 
piston 139 of hydraulic ram 29 moves, lower plate 137, in turn, moves 
causing movement of piston 135 within vacuum cylinder 55. A potentiometer 
141 is connected via wire 143 with lower plate 137 for calibration of the 
stroke limits of hydraulic ram 29. 
SYSTEM OPERATION 
In the preferred embodiment, the apparatus of the invention is operated via 
a control system which stores a complete set of digital commands for 
replication of a predetermined draw profile. Each command advantageously 
includes (i) a positional command for the hydraulic ram; (ii) a command 
for puff valve 49 defining either an exhaust (open) or suction (closed) 
state; (iii) a command for automatic lips defining either an open or 
closed state and; (iv) two commands for the automatic lighter, one for the 
on or off state and one for the contact or retracted state. 
The commands thus define the state of the apparatus at periodic intervals 
of, e.g., 20-100 milliseconds. During the puff phase of a draw profile, 
the commands sent to the hydraulic ram define increasingly lower ram 
positions; the puff valve is closed; lips are closed and the lighter is 
off and retracted (unless the puff is a lighting puff). During smolder, 
the puff is normally exhausted. In this case, the ram is advantageously 
moved first to a position 1/2 the distance from a full upstroke and then 
to a position at full upstroke while the puff valve is open. This 
accomplishes rapid exhaust. In some instances, the control system 
determines that exhaust cannot be carried out in the allotted smolder 
time. In such case, the machine holds the puff during smolder and exhaust 
is simply skipped. During the next smolder, a double puff is then 
exhausted. 
Details of the system operation are set forth below, in the context of a 
preferred embodiment for "human mimic" operation. Those skilled in the art 
will recognize that the invention is however applicable to less complex 
operations, as for example, a programmable system for a plurality of 
predetermined draw profiles or for a system wherein a given puff profile 
can be varied by operator instructions to the control system. 
FIG. 6 illustrates a general overview of a preferred system operation which 
is conducted using a microcomputer. With reference to FIG. 6, a first step 
involves machine preparation, discussed in further detail later. A human 
data smoking file has been loaded into data storage means and is accessed 
in step 603. In step 605 the program indicates to the operator via CRT 
screen 24 (FIG. 1) that cigarettes are to be loaded and lighters adjusted. 
These steps can be performed automatically. In the apparatus shown in 
FIGS. 1-5, the cigarettes are loaded and the lighters adjusted manually. 
An operator loads individual smoking articles into the holders shown in 
FIGS. 4 and 4A, discussed previously. Lighters which are in the contact 
configuration shown in FIG. 2 are moved upon support 79 until the lighting 
coil of the lighter touches the lighting end of each smoking article. 
At this point, the control system will read the complete data file of the 
recorded draw profile, one datum point at a time, and will generate a 
complete set of machine operation commands, each comprising a 16 bit 
array, for each 40 millisecond interval of the recorded draw profile, as 
indicated in step 607. As indicated previously, a human draw profile 
consists of a sequence of pressure differential readings taken 
periodically, in this case, every 40 milliseconds. Prior to use in the 
control system discussed herein, the draw profile data are preferably 
converted into linear distances (centimeters) defining the instantaneous 
position of the piston within the smoking machines vacuum cylinder. Such 
conversion is discussed in greater detail hereinafter. It will be apparent 
to those skilled in the art that the data can be provided to computer 23 
in the form of 40 millisecond pressure differential readings and the 
conversion to piston positions carried out as a part of the control method 
of FIGS. 6-10. It will also be apparent that a complete set of commands 
may be input at this point where the commands have been previously 
determined. 
The human draw profile data which is input into the system consists of puff 
phases and smolder phases which are located between the puff phases. 
During the smolder phases, the recorded pressure differential will be 
zero. In the preferred method discussed herein, puff profile data file 
will consist of pressure differential readings for each 40 milliseconds of 
a puff phase while the smolder phase is indicated by both a zero character 
and time characters which, in turn, represent the duration of smolder 
phase. 
The commands generated in step 607 for each 40 millisecond datum point are 
advantageously 16 bit arrays. The first 12 bits of the 16 bit array are 
used for defining the position of the piston in the vacuum cylinder. Thus, 
the position can be any one of 4,096 positions (2.sup.12 positions). Of 
the remaining 4 bits, one bit is used for puff valve 49 and defines either 
an inhale or exhaust state. One bit is used for the valve controlling the 
lips and defines an opened or closed state. One bit is used for the valve 
controlling pneumatic supply to the automatic lighter and defines either a 
contact or retracted state. The final bit is used for electric supply to 
the lighter and defines either an on or off state. 
Following generation of the complete set of machine instructions in the 
form of 16-bit arrays, the arrays are fed to interface 25, one at a time 
every 40 milliseconds, until the recorded draw profile has been 
replicated. This is indicated in step 609. Thereafter, the control 
sequence is ended as indicated in bock 611. 
FIG. 7 illustrates in greater detail the initiation phase of that control 
sequence. The first step of the control sequence, step 701, involves 
initialization of all interfaces, the keyboard, printer, arrays and the 
restart flag. In step 703, a signal is sent to the human operator via CRT 
instructing the operator to calibrate stroke limits. The objective of this 
step is to calibrate voltage readings from potentiometer 141 with each of 
the 4,096 positions of piston 139 in hydraulic ram 29 and the calibration 
thereof to linear distance readings. Specifically, in step 703, lower 
plate 137 (FIG. 5) is first set by the computer at its uppermost location. 
The distance between upper plate 133 and lower plate 137 is determined 
automatically or manually and recorded. Thereupon, lower plate 137 is 
automatically moved to its lowermost position and the distance between 
upper plate 133 and lower plate 137 is measured and recorded. The computer 
then calculates the distance between the upper and lower stroke limits and 
determines the physical increment in centimeters for the 4,096 possible 
positions of the piston. This is then automatically correlated with 
readings from potentiometer 141 to determine the correspondence between 
millivolts and distance. It will be recognized that since lower plate 137 
is connected via piston rod 135 to the piston within vacuum cylinders, the 
correlation between volume changes within the vacuum cylinder 55 and 
linear position changes of lower plate 137 can now be correlated 
precisely. 
Step 705 is the restart point. As discussed in greater detail with 
reference to FIG. 10, at the end of the control sequence, new data can be 
input into the system for mimic of a new puff profile. When the system is 
restarted in this manner, steps 701 and 703 are bypassed and the system 
starts at step 705. 
In step 707, the operator is instructed to input constants for exhausts, 
puff decay and the desired number of lighting puffs. The exhaust constant 
represents the minimal time which is required by the system to exhaust a 
tobacco puff. This is determined experimentally and normally ranges from 
about 120 to about 520 milliseconds. The constant for puff decay 
represents the amount of time following movement of the piston within the 
vacuum cylinder for the system to reach a state of quiescence. In other 
words, as smoke is puled through a cigarette and into the vacuum cylinder, 
a certain amount of time, normally between about 40 and about 120 
milliseconds (depending on the system setup), is required for the smoke to 
reach a state of quiescence following passage of the smoke through the 
cigarette and into the system. This time period is referred to herein as 
puff decay. Both exhaust and puff decay constants can be input 
automatically. 
Also in step 707, the operator has the option to input the number of 
lighting puffs. During the lighting of a cigarette, at least the first and 
sometimes more puffs are lighting puffs wherein the cigarette is being 
lit. If this is observed manually, the number of lighting puffs can be 
input at step 707. Otherwise, the control system will automatically 
determine the number of lighting puffs as discussed later with regard to 
FIG. 9. 
In step 709, the system automatically initializes the input/output buffer 
and sets the error trap per step 711. The error trap set in step 711 
instructs the system to proceed to step 1015 (FIG. 10) when a null 
character is detected in an array. 
The system then proceeds to step 713 wherein the data file of a recorded 
draw profile is first opened. Thereupon, identification information is 
read from the file and the expected number of data points is determined. A 
data point counter is automatically set in the system so that the system 
will be able to properly identify the last datum, or end of data. 
In step 715, the operator is instructed via the CRT to insert cigarettes 
and adjust lighters. At this point, the smoking machine apparatus 
automatically adjusts the lips to their opened position so that cigarettes 
can be inserted and will adjust the lighters to their contact position so 
that they may be slidably adjusted upon support 79 (FIG. 3) until the 
lighter element is in contact with the end of smoking article 41 (FIG. 3). 
Step 715 is also the initiation point for a replicate command which is 
discussed with reference to FIG. 10. 
In step 717, the system examines the replicate flag and proceeds to the 
output phase of the program, FIG. 10, block 1000, if the replicate flag is 
set to one. Assuming that there is no replicate command and thus the 
replicate flag equals zero, the system proceeds on to step 719 wherein 
flags and counters are initialized to zero. The system preferably contains 
the following flags and counters: 
a flag to indicate whether or not all data have been read; 
a flag to indicate whether or not a given puff has been been exhausted; 
a flag to indicate whether or not the puff immediately prior to a given 
puff has been exhausted; 
a counter to determine the number of data points read; 
a counter to enumerate the command arrays stored within the computer 
memory; 
a counter to enumerate the beginning and/or end points of each puff 
contained within the data; 
a counter to enumerate the number of data points contained within all 
lighting puffs; and 
a counter to enumerate the number of puffs as each is processed. 
The system then proceeds to step 800 wherein in this instance the first 
datum point of the recorded draw profile is read by the system. In step 
801, the system determines whether the datum represents datum from a 
lighting puff. Assuming this datum is the first datum of the first puff 
and thus is a lighting puff, the system proceeds to step 803 wherein the 
lighting puff counter is automatically adjusted one point higher thus 
counting the number of lighting puff data. Thereupon, the system proceeds 
to step 805 wherein the total data counter is examined to determine 
whether this datum represents the last datum point. Since this is the 
first datum point, the answer is no and the system proceeds to step 807. 
In step 807, the system examines the datum to determine whether it 
represents the beginning of the first puff or the end of any puff. As 
indicated previously, at the end of any puff, there is a smolder phase 
which is indicated by the character zero. Likewise, the first character of 
the first puff is also zero. Thus, if the datum being examined in step 807 
is a zero, the answer will be yes. Assuming that this datum point is the 
first datum of the first puff, the datum is zero and the system proceeds 
to step 809. 
In step 809, the exhaust flag is examined. This flag is automatically set 
from zero to one when the system does not exhaust (holds its breath) 
between puffs. Since the exhaust flag was set at zero in step 719, the 
system proceeds to step 811 wherein the datum is examined to determine 
whether it represents the beginning of a first puff. In this instance, it 
does and the system then proceeds to step 813. 
In step 813, a complete array is generated for the single datum point. In 
this case, the array will be vacuum cylinder position zero, puff valve set 
to inhale state, lips in the closed state. The remaining two bits in the 
array are for the automatic lighter position and lighter heating element 
on or off. At this particular point, the array is always set to lighter 
retracted and element off. At a later point in the control program, step 
937 (FIG. 9), the system will automatically adjust the two bits for 
lighter position and lighter element for each of the lighting puff arrays. 
Following step 813, the system returns to step 800. In step 800, the system 
reads the second datum of the first lighting puff and proceeds to step 
801. Since this is still a lighting puff, the counter is adjusted in step 
803 and the system proceeds to step 805. This is not the end of the data 
and the system proceeds to step 807. 
In step 807, it is determined that the datum is neither the beginning of 
the first puff nor the end of any puff and the program proceeds to block 
815. The exhaust flag is set at zero so that the program proceeds to block 
817. In block 817, the datum is examined to determine whether there is 
sufficient stroke remaining upon the piston of the vacuum cylinder to 
proceed to the location indicated in the datum. If not, the program 
proceeds to step 819 wherein an abort command sends the program to a later 
phase discussed in FIG. 10. Assuming there is sufficient stroke remaining, 
the program proceeds to step 813 wherein a complete array is generated as 
discussed previously (cylinder position, vacuum cylinder valve in inhale 
state, lips closed, lighter retracted, lighter off). 
Blocks 821 and 823 are used when the exhaust flag is set at one. As 
discussed later with reference to FIG. 9, in those instances when there is 
not sufficient time to exhaust between puffs, the vacuum cylinder "holds 
its breath" and the exhaust flag is then set to one. In those instances, 
the portion of the array representing the position will have its basis 
adjusted as indicated in steps 821 and 823 to reflect that the starting 
point of the puff is not position zero. 
Still with reference to FIG. 8, data are continually read and arrays 
generated for each datum point of the first puff. When the datum point 
representing the end of the first puff is reached, i.e., when a zero is 
detected, the program proceeds from step 807 to step 809. Since the 
exhaust flag is still set at zero, the program proceeds to step 811 and 
from there to block 900, FIG. 9, since the datum does not represent the 
beginning of the first puff. 
With reference to FIG. 9, the datum representing the end of the first puff 
will be a zero. The next four data are time data which indicate when the 
puff ended and when the next puff begins. In the steps represented by 
block 900, the smolder time is calculated and converted into 40 
millisecond intervals. The program proceeds to step 901 wherein it 
determines whether there is sufficient time to conduct an exhaust cycle. 
An exhaust cycle consists of several parts. A first puff decay part, 
discussed previously, plus two 40 millisecond intervals for exhausting the 
vacuum cylinder in two steps; plus sufficient decay time to allow vacuum 
cylinder and valves to reach a state of quiescence following exhaust, 
i.e., exhaust decay. The time needed for exhaust (which is contained as a 
constant in memory storage) is compared in step 901 with the time 
calculated in step 900 to determine whether there is sufficient time for 
exhaust. Assuming there is not sufficient time for exhaust, the program 
then proceeds to step 903 wherein the exhaust flag is set to one, and the 
basis or position of the cylinder is recorded in memory. Additionally, in 
step 903 wait arrays are generated for the smolder cycle. Each wait array 
tells the vacuum cylinder piston to remain at the same location, however, 
two types of waits are generated. A first set of wait signals provide for 
the puff decay cycle. In these wait arrays, the lips remain closed and the 
vacuum cylinder valve remains in the inhale state. In this case (i.e., the 
puff will not be exhausted), the waits for the portion of the smolder 
cycle following the puff decay waits set the vacuum cylinder valve in the 
inhale configuration and sets the simulated lips in the closed 
configuration. The number of puff decay waits is determined by constants 
fed into the system earlier. The number of smolder waits is determined by 
the length of the smolder time in the recorded draw profile. Thereupon the 
program returns to FIG. 8 block 800 wherein a new datum representing a 
portion of a puff is read. The system then generates arrays for each datum 
point of this next puff in the previously discussed manner. 
Upon reaching the last datum point of this puff, the program again returns 
to block 900 and to block 901. Assuming there is sufficient time to 
exhaust, the program proceeds to step 905 wherein the exhaust flag is 
examined. Assuming the exhaust flag is one, the program proceeds to step 
907 wherein puff decay wait arrays are generated (same position as last 
position, vacuum cylinder valve in inhale state, lips closed.) The program 
then proceeds to step 909 wherein the exhaust flag is now reset to zero, 
and onto step 911. In step 911, a single array is generated for movement 
of the vacuum piston to a position one-half the distance to a full exhaust 
with puff valve in exhaust state and lips open. The program proceeds to 
step 913 and assuming there are more puffs in the stored draw profile, 
onto step 915. In step 915 an array is generated for the remainder of the 
exhaust stroke, and additionally exhaust decay waits are generated. The 
exhaust decay waits maintain the vacuum piston at its maximum up or closed 
position and maintain the vacuum cylinder valve in the exhaust state and 
the lips in the open state. The program proceeds to step 917 wherein 
another array is generated for the same position but with closed lips and 
vacuum cylinder valve in the inhale state. 
The arrays for completion of the exhaust cycle having been completed, the 
program returns to block 800 and proceeds through the cycle shown in FIG. 
8 until a complete set of arrays has been generated for the next puff 
cycle. Thereupon, the program reaches a datum representing a puff end and 
returns to block 900 and onto block 901. Assuming there is time for 
exhaust, the program proceeds to step 905. Since the exhaust flag is now 
set to zero, the program proceeds to step 919 wherein a single wait array 
is generated. The program then proceeds to step 921 wherein puff decay 
wait arrays are generated in the manner discussed earlier. 
The program then proceeds, as discussed previously, through steps 911, 913, 
915, 917 and back to block 800. The program then proceeds through the 
remaining puff and smolder cycles until it reaches the end of data at 
block 805 (FIG. 8). 
When the last datum point is reached, the control system proceeds to step 
923 (FIG. 9). In step 923, the end of data flag is set to a value of one, 
and the program proceeds to step 925. If the previous puff has not been 
exhausted, the basis position is adjusted in step 927 and the program 
proceeds to step 929. If insufficient stroke is remaining as determined in 
step 929, the program proceeds to the abort cycle indicated at block 931 
and otherwise proceeds to step 919 and on to steps 921, 911 and 913 
discussed previously. In step 913, the end of data flag is detected and 
the program proceeds to step 933 wherein an array for the remainder of the 
exhaust stroke is generated. The program then proceeds to step 935 wherein 
a null character is added as the final array. Thereupon, the program 
proceeds to step 937. In step 37, the lighting puff counter set in step 
803 is examined. The number of lighting puff data is determined by reading 
the counter. The arrays corresponding to each of those lighting puff data, 
together with the intervening smolder cycles (if there is more than one 
lighting puff) are adjusted. To each of these arrays are added 
instructions for the automatic lighter position bit and the automatic 
lighter on/off bit. These bits are adjusted to be set at lighter position 
in contact position and lighter on. 
In a preferred embodiment of the control system, step 937 includes a 
subroutine which automatically calculates the number of lighting puffs. 
This is accomplished by comparing the intervals between the first three 
puffs with an experimentally determined constant of 3000 milliseconds. If 
the inter-puff intervals are shorter than this time, the puffs are assumed 
to be lighting puffs and the arrays for lighter position and on/off are 
then adjusted. One, two or three (but no more than three) lighting puffs 
may thus automatically be selected. 
The program then proceeds to the output phase discussed with reference to 
FIG. 10. 
With reference to FIG. 10, the program proceeds to the output phase when a 
complete set of arrays for the recorded draw profile have been generated. 
In step 1000, a series of warning signals is activated indicating that the 
automatic smoking machine is about to be set in motion. The program 
proceeds to step 1001 wherein a signal is fed to interface 25 for 
retracting the lighters, closing simulated lips and again warning. The 
program proceeds to step 1003 wherein the system waits for the keystroke 
command "start" and again warns. 
Upon input of the start command, the program proceeds to step 1005 wherein 
a signal is sent to interface 25 for preheating of the lighters. The 
lighters are preheated for a period of about ten seconds and the program 
proceeds to step 1007 wherein the lighters are moved into contact with the 
cigarettes and the end of the cigarette is preheated for a period of about 
one second. Following preheating of the cigarettes, the program proceeds 
to step 1009 wherein the first datum in the array is output to interface 
25. The program proceeds to step 1011 wherein there is a wait of 40 
milliseconds. If datum does not consist of the null character, the program 
returns to step 1009 and outputs the second array. This cycle continues 
for the entire set of arrays representing the recorded draw profile data 
until the null character is detected at 1013. An attempt to transfer the 
null character to the output buffer causes an error condition to arise, 
and, thereupon, the program proceeds to step 1015. It will be recognized 
that each array will now carry instructions for cylinder position, puff 
valve, automatic lips, lighter position and lighter element. Operation of 
puff valve, automatic lips, lighter position and lighter element has been 
discussed previously. Piston position is controlled by valve 37 (FIG. 1) 
which allows sufficient hydraulic fluid to move into or out of hydraulic 
ram 29 during the 40 millisecond period for the ram piston to move from 
its existing position to the position dictated by the array. 
In step 1015, the 40 millisecond output timer is disabled and the error 
trap is likewise disabled. The program then proceeds to step 1017 wherein 
a report is generated. The report preferably contains the following data: 
the date and time of day, the data file name, the name (version) of the 
control program, the calibration factor, the program line number wherein 
the error condition arose, the error code number, the interface select 
code (identifies the I/O buffer), the expected and found number of puffs 
and additional information regarding the cigarette and flow measurement 
device used in the original puffing measurements. 
The program then proceeds to step 1019 wherein a warning is issued, and on 
to step 1021 wherein the lips are opened and the program waits while 
cigarette butts and Cambridge filter pads are removed for analysis. 
Thereupon, the keystroke command representing either continue, replicate, 
or stop is entered (step 1023) and the program continues to step 1025. If 
the continue stroke has been entered, the program returns to step 705 to 
begin a new recorded draw profile. 
If continue has not been input in step 1023, the program continues to step 
1027. If the command replicate was entered in step 1023, the program 
proceeds from step 1027 to step 1029 wherein the replicate flag is set to 
one and the program then returns to FIG. 7, block 715. 
If the replicate command has not been entered, the program proceeds to step 
1031 wherein a warning is issued that the system is about to turn off. In 
step 1033, the system is automatically shut down. 
The abort cycle is also indicated in FIG. 10. As indicated previously, when 
the data analysis and array generation portion of the program determines 
that there is insufficient stroke remaining in the vacuum cylinder to 
proceed to the necessary position, an abort command is entered. In this 
case, the program proceeds to step 1035 wherein the timer is disabled, the 
file is closed, and a warning issued. Thereupon, the program proceeds to 
step 1019 and through the remaining steps, discussed above. 
DATA ACQUISITION AND CONVERSION 
As indicated previously, the data is collected by monitoring a desired draw 
profile, preferably of a human, and recording digitally, pressure 
differentials. Advantageously, pressure differentials are recorded every 
40 milliseconds. If desirable, pressure differentials can be recorded 
every 20 milliseconds to more accurately determine the beginning of a 
puff. In the latter case, the datum representing the first puff datum and 
the remaining odd numbered data, i.e., data 1, 3, 5, 7 etc., are saved to 
generate the 40 millisecond draw profile. Even numbered data, i.e., data 
2, 4, 6, 8 etc., can be discarded, thus providing data recorded every 40 
milliseconds. The above recorded flow profiles represent 40 millisecond 
measurements of flow rate. These are readily converted to volume per 40 
milliseconds, i.e., flow rate times 40 milliseconds equals volume of puff 
in the 40 millisecond interval. Volume can then be converted into linear 
distances inside the vacuum cylinder since the internal diameter of the 
vacuum cylinder is known precisely. The resultant data can be used in the 
smoking machine of the invention. 
In a most advantageous embodiment of the invention, the data is corrected 
or massaged to minimize so-called dynamic error. As with any dynamic 
control system, there is an inherent machine distortion of the input 
signal which results in imperfectly reproduced puff profiles. For the 
apparatus of this invention, this error takes primarily the form of a time 
lag and subsequent amplitude reduction error in the response (output) 
signal. This dynamic error is due to the parts making up the apparatus. 
Specifically, the apparatus consists of many varied interacting 
components--electronics, pistons, pump, hoses, mechanical parts, etc. 
During operation, each component is subject to one or more disruptive, 
"dissipative forces". Pistons are slowed by friction; airflow in hoses is 
complicated by turbulence and dead volumes; electrical conductivity is 
hindered by heated circuits. All contribute to decreased efficiency of the 
machine's working parts. Moreover each movement of the piston is affected 
by the previous movement of the piston. 
Such dynamic error can be minimized or eliminated by the application of 
mathematical control theory. As will be recognized by those skilled in the 
art, control theory may be applied using either "classical" (Laplace 
domain) or "modern" (time domain) methodology. 
One preferred dynamic error correction system was developed based on the 
following. 
Using standard techniques of classical control theory (manipulations in 
Laplace domain) a massage of the measured human puff profiles was carried 
out to compensate for response error in the automated smoking apparatus. 
The mathematical procedure followed consisted of three primary steps. Each 
is described below. 
The first step consisted of determining the system transfer function. This 
was accomplished by measuring the response of the machine to input flow 
step functions of varying magnitude. To account for the great majority of 
human puff flow rates, a step function of magnitude 80 cc/sec was selected 
as the final standard. The resulting output flow curves were fit using 
standard nonlinear regression techniques (Statistical Library for HP9826 
and HP9836 Computers, Hewlett Packard, 1982) to a time domain response 
function containing two exponential terms. (Two exponential terms were 
found to yield sufficient fitting accuracy.) The resulting transfer 
function (second order) was then computed as 
EQU T(s)=N*[(As.sup.2 +Bs+C)/(s.sup.2 +Ds+E)] 
where N, A, B, C, D and E are simple functions of the fitting parameters. 
In the final realization of the massage algorithm, the parameters 
(especially "N") were varied freely by trial and error to test system 
sensitivity and to achieve a final optimal set for human profile 
reproduction. 
The second step of the procedure involved preliminary treatment of the 
human puff profile data to prepare it for control theoretic massage. This 
is accomplished in two stages. First, the original flow data is smoothed 
by a compound running-median/hanning routine (Velleman and Hoaglin) to 
remove excessive noise in the profile. Next, the smoothed profile is 
subjected to a Fourier series analysis (HP98821A BASIC Numerical Analysis 
Library For the HP9826 and HP9836 Computers) to provide a continuous, 
series representation of the discrete flow rate data. Approximating the 
profiles by accurate Fourier series makes possible an analytic solution to 
the fundamental equation relating input and output signals. 
Finally, combining the transfer function and series representations of puff 
data in the central control theory equation, provided the solution (in the 
Laplace domain) for that signal which produces the given human profile. 
Expression of the data in Fourier series form then allowed analytic 
inversion from the Laplace to time domains. The final form of the desired 
machine input signal is 
##EQU1## 
where a.sub.n and b.sub.n are Fourier series coefficients of the smoothed 
profile; r.sub.1, r.sub.2, C.sub.1, C.sub.2, C.sub.3, 1.sub.3, 1.sub.4, 
m.sub.3 and m.sub.4 are simple functions of the transfer function 
parameters; and x.sub.n is related to the period of the Fourier expansion. 
At any given time interval, this equation may be used to estimate the 
proper input flow rate (converted to voltages) that the smoking machine 
should receive to achieve a given output profile. 
The procedure outlined above makes use of several standard numerical 
software algorithme including smoothing, splines, regression and Fourier 
series analysis. While any reliable version of these routines should 
suffice, the inventors have employed with success the smoothing 
algorithims found in Applications, Basics and Computing of Exploratory 
Data Analysis (P. F. Velleman and D. C. Hoaglin, PWS Publishers, 1981); 
the cubic spline and Fourier series routines found in the HP98821A BASIC 
Numerical Analysis Library for the HP 9826 and HP 9836 Computers 
(Hewlett-Packard Company, 1982); and the nonlinear regression routine from 
the Statistical Library for the HP 9826 and 9836 Computers 
(Hewlett-Packard, 1982). 
Those skilled in the art will recognize that other analyzing or correcting 
systems can be employed for eliminating or minimizing to the desired level 
the inherent dynamic error. 
In order to verify accuracy of the method and apparatus of the invention, a 
cigarette was smoked in a manner to provide "extreme" puff profiles which 
are known to be difficult to mimic by machine. During the smoking, the 
flow rate of puffs was monitored and recorded in the aforedescribed 
manner. Thereafter, cigarettes were smoked by a human mimic smoking 
apparatus substantially in the same form shown in FIG. 1. In one instance, 
the recorded data were fed to the automatic smoking apparatus in 
uncorrected form. In a second instance, the data were corrected according 
to the above-described procedure and then transmitted to the automatic 
smoking machine. In both instances, the instantaneous flow volumes of the 
cigarette being smoked by the automatic smoking machine were monitored and 
recorded by inserting the flow rate measuring device between the burning 
cigarette and the automatic lips of the automatic smoking machine. FIG. 11 
graphically compares the single puff: (a) as smoked by a human; (b) when 
the recorded data are fed to the automatic smoking machine without prior 
correction; and (c) when the data are corrected according to the above 
described procedure before being fed to the automatic smoking machine. It 
can be seen that data correction substantially improves performance of the 
automatic smoking machine. When analyzed by a common least-squares error 
measure, the corrected data shown in FIG. 11 represents a 79% improvement 
over the non-corrected data when used for machine instructions. In a 
similar manner, other "extreme" puffs were generated and mimicked by the 
automatic smoking machine with and without data correction. Percent 
improvement of puff replication or mimicking ranged from 72% to 88%. 
Those skilled in the art will recognize that other data correction 
techniques may be used to improve replication or mimic of recorded puff 
profiles by the automatic smoking machine of the invention. 
The invention has been described in considerable detail with reference to 
preferred embodiments. However, variations and modifications can be 
effected within the spirit and scope of the invention as described in the 
foregoing specification and defined in the appended claims.