U.S. patent number 3,646,890 [Application Number 04/880,582] was granted by the patent office on 1972-03-07 for means for controlling automatically moved vehicle.
This patent grant is currently assigned to Clark Equipment Company. Invention is credited to James H. Snyder.
United States Patent |
3,646,890 |
Snyder |
March 7, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
MEANS FOR CONTROLLING AUTOMATICALLY MOVED VEHICLE
Abstract
A material unit handling and storage system has a stacking
vehicle movable within an aisle between loading stations at each
column of bins. The location of the vehicle within the aisle is
sensed by a group of magnetically activated switches on the vehicle
that respond to coded magnetic strips placed adjacent each station.
A pulse clock and pulse counter system provide correlated pulses
and information on the location of the vehicle and the selected
destination for the vehicle is stored in count coincident detectors
that produce an output upon the occurrence of the pulses
corresponding to the location and destination. The difference in
time of the occurrence of the pulses provides information to a
driving control means that moves the vehicle in the desired
direction at high, intermediate and low speeds as it nears its
destination and at a fine positioning speed when it arrives at its
destination.
Inventors: |
Snyder; James H. (Battle Creek,
MI) |
Assignee: |
Clark Equipment Company
(N/A)
|
Family
ID: |
25376588 |
Appl.
No.: |
04/880,582 |
Filed: |
November 28, 1969 |
Current U.S.
Class: |
104/307; 318/603;
414/273; 700/77; 700/228 |
Current CPC
Class: |
B65G
1/0421 (20130101); G05B 19/291 (20130101) |
Current International
Class: |
B65G
1/04 (20060101); G05B 19/19 (20060101); G05B
19/29 (20060101); G05b 019/00 () |
Field of
Search: |
;214/16.42 ;307/231
;328/48,49 ;104/88 ;318/601,603 ;235/150.2,24 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: La Point; Arthur L.
Assistant Examiner: Libman; George H.
Claims
I claim:
1. A vehicle control system having a vehicle movable to a plurality
of stations along a selected path, a driving means for moving the
vehicle, and a means for controlling the driving means, said means
for controlling comprising:
a designation means for producing a unique designation signal for
each respective station,
a pulse means for producing groups of pulses correlated by sequence
of occurrence to sequence of position of the stations,
said pulse means comprising a pulse generator means for producing a
continuous series of pulses, and a counting means adapted to
receive the pulses for producing the defined groups of pulses
correlated by sequence of occurrence to the sequence of position of
the stations,
a location means responsive to the groups of pulses and responsive
to the unique designation signals for producing a location signal
pulse indicating the station at which the vehicle is located,
said location means comprises a location sensing means connected to
the vehicle and adapted to respond to the destination means at the
station at which the vehicle is located for producing a vehicle
location signal indicating the location of the vehicle at said
station, and a location indicating means correlated to and
responsive to the pulse means output and the vehicle location
signal for producing the location signal pulse upon the occurrence
of the counting means pulse corresponding to the station indicated
by said vehicle location signal,
a destination means responsive to the groups of pulses for
producing a destination signal pulse indicating the station
selected as the vehicle destination, and
a control means responsive to the location signal pulse and the
destination signal pulse for controlling the driving means to move
the vehicle.
2. A vehicle control system according to claim 1 wherein said
destination means comprises a destination signal means for
producing a destination signal indicating the selected vehicle
destination, and a destination indicating means correlated to and
responsive to the counting means pulses and to the destination
signal for producing the destination signal pulse.
3. A vehicle control system according to claim 2 wherein said
control means comprises a direction means responsive to the
sequence of occurrence of the location signal pulse and the
destination signal pulse for controlling the driving means to move
the vehicle in the direction corresponding to the sequence of
occurrence of said signal pulses and thereby in the direction
toward the station selected as the destination station.
4. A vehicle control system according to claim 3 wherein said
control means comprises an interval sensing means for counting the
number of interval pulses occurring between the occurrence of the
location signal pulse and the occurrence of the destination pulse
and for controlling the driving means to move the vehicle at a
higher selected velocity when the number of said interval pulses is
greater than a selected number and to move the vehicle at a lower
selected velocity when the number of interval pulses is equal to or
fewer than said selected number.
5. A vehicle control system according to claim 4 also comprising a
destination sensing means responsive to the simultaneous occurrence
of the location signal pulse and the destination signal pulse for
indicating the location of the vehicle at the selected vehicle
destination.
6. A vehicle control system according to claim 1 wherein said
control means comprises an interval sensing means for counting the
number of interval pulses occurring between the occurrence of the
location signal pulse and the occurrence of the destination pulse
and for controlling the driving means to move the vehicle at a
higher selected velocity when the number of said interval pulses is
greater than a selected number and to move the vehicle at a lower
selected velocity when the number of interval pulses is equal to or
fewer than said selected number.
7. A vehicle control system according to claim 1 wherein said
control means comprises an interval sensing means for counting the
number of interval pulses indicating the number of stations between
the vehicle location and the vehicle destination occurring between
the occurrence of said two signal pulses and for controlling the
driving means to move the vehicle at a high selected velocity when
the number of said interval pulses is greater than a first selected
number, to move the vehicle at an intermediate selected velocity
when the number of interval pulses is equal to or fewer than said
first selected number and greater than a second selected number,
and to move the vehicle at a low selected velocity when the number
of interval pulses is equal to or fewer than said second selected
number.
8. A vehicle control system having a vehicle movable to a plurality
of stations along a selected path, a driving means for moving the
vehicle, and a means for controlling the driving means, said means
for controlling comprising:
a designation means for producing a unique designation signal for
each respective station,
a pulse means for producing groups of pulses correlated by sequence
of occurrence to sequence of position of the stations,
a master pulse generator means for producing a continuous series of
pulses located in the main control center,
a slave pulse generator means for producing a continuous series of
pulses located in the remote control center,
a main counting means located in the main control center adapted to
receive pulses from the master pulse generator for producing
defined groups of pulses correlated by sequence of occurrence to
the sequence of position of the stations,
a remote counting means located in the remote control center
adapted to receive the pulses from the slave pulse generator,
a synchronizing means located for synchronizing outputs of the
first and second counting means,
a location means responsive to the groups of pulses and responsive
to the unique designation signals for producing a location signal
pulse indicating the station at which the vehicle is located,
a destination means responsive to the group of pulses for producing
a designation signal pulse indicating the station selected as the
vehicle's designation, and
a control means responsive to the location signal pulse and a
destination signal pulse for controlling the driving means to move
the vehicle.
9. A vehicle control system according to claim 8 wherein said
designation means comprises magnetic devices at each respective
station positioned to produce coded magnetic fields unique to each
respective station.
10. A vehicle control system according to claim 9 wherein said
pulse means comprises a multivibrator producing a continuous series
of pulses; and a digital counter connected to receive the pulses
and to produce an output defining said pulses in repeating groups
of pulses starting with a selected start pulse with the pulses of
said groups of pulses individually corresponding to respective
stations.
11. A vehicle control system according to claim 10 wherein said
location means comprises a sensing device having groups of
magnetically responsive reed switches mounted on the vehicle
adapted to respond to the designation device magnetic fields at the
stations when the vehicle is at a respective station to produce a
vehicle location signal indicating the position of the vehicle at
said respective station; and a coincidence counter detector
connected to receive the digital counter output and the vehicle
location signal for producing a location signal pulse upon the
occurrence of the pulse corresponding to the station indicated by
said vehicle location signal.
12. A vehicle control system according to claim 11 wherein said
destination means comprises a second coincidence counter connected
to receive the digital counter output and to receive an input
indicating a station selected as the vehicle destination.
13. A vehicle control system according to claim 12 wherein said
control means comprises:
a switching circuit responsive to a first occurring location signal
pulse to produce an output of one polarity and to a first occurring
destination signal pulse to produce an output of another
polarity;
a means responsive to the polarity of the control signal to control
the driving means to move the vehicle in one direction with one
polarity and the other direction with the other polarity;
a ripple counter connected to count the number of interval pulses
occurring between the occurrence of the first occurring signal
pulse and the second occurring signal pulse; and
means responsive to the ripple counter output for controlling the
driving means to move the vehicle at a higher selected velocity
when the number of said interval pulses is greater than a selected
number and to move the vehicle at a lower selected velocity when
the number of interval pulses in equal to or fewer than the
selected number.
14. A vehicle control system according to claim 13 wherein said
destination means also comprises a centering magnet located to
provide a final positioning signal; and said system also comprises
an AND gate connected to receive the signal pulses to produce an
output when said signal pulses are simultaneous, and means
responsive to the AND gate output for controlling the driving means
from the centering magnet to center the vehicle at its destination
station.
15. A vehicle control system having a vehicle movable to a
plurality of stations along a selected path, a driving means for
moving the vehicle, and a means for controlling the driving means,
said means for controlling comprising:
a designation means at each station for producing a unique
designation pulse group signal for each respective station,
a pulse means for producing defined groups of pulses correlated by
sequence of occurrence to sequence of position of the stations with
at least of said pulses respectively corresponding to said
stations,
a location means responsive to the groups of pulses and responsive
to the unique designation signals for producing a location signal
pulse upon the occurrence of the pulse group signal corresponding
to said station thereby indicating the station at which the vehicle
is located;
a destination means responsive to the groups of pulses for
producing a destination signal pulse upon the occurrence of the
pulse group signal corresponding to a selected vehicle destination
station thereby indicating the destination station of the vehicle;
and
a control means responsive to the location signal pulse and the
destination signal pulse for controlling the driving means to move
the vehicle at a selected velocity in the direction toward the
station selected as the destination station.
16. A vehicle control system according to claim 15 wherein said
pulse means comprises a pulse generating device producing a
continuous series of pulses; and a counting means adapted to
receive the pulses for grouping the pulses into defined repetitive
groups correlated by sequence of occurrence to the sequence of
position of the stations with each of said stations corresponding
to one of said pulses of each of said groups.
17. A vehicle control system according to claim 16 wherein said
location means comprises a location sensing means connected to the
vehicle and adapted to respond to the designation signal at the
station at which the vehicle is located for producing a vehicle
location signal indicating the location of the vehicle at said
respective station; and a location indicating means correlated to
and responsive to the counting means pulses and the vehicle
location signal for producing the location signal pulse upon the
occurrence of the counting means pulse corresponding to the station
indicated by said vehicle location signal.
18. A vehicle control system according to claim 17 wherein said
destination means comprises a means for producing a destination
signal indicating the selected vehicle destination, and a
destination indicating means correlated to and responsive to the
counting means pulses and the destination signal for producing the
destination signal pulse upon the occurrence of the counting means
pulse corresponding to the selected vehicle destination.
19. A vehicle control system according to claim 18 wherein said
control means comprises a direction means responsive to the
sequence of occurrence of the location signal pulse and the
destination signal pulse for controlling the driving means to move
the vehicle in the direction corresponding to the sequence of
occurrence of said two signal pulses and thereby in the direction
toward the station selected as the destination station.
20. A vehicle control system according to claim 19 wherein said
control means comprises an interval sensing means for counting the
number of interval pulses occurring between the occurrence of the
location signal pulse and the occurrence of the destination pulse
and for controlling the driving means to move the vehicle at a
higher selected velocity when the number of said interval pulses is
greater than a selected number and to move the vehicle at a lower
selected velocity when the number of interval pulses is equal to or
fewer than said selected number.
21. A vehicle control system according to claim 19 wherein said
control means comprises an interval sensing means adapted to count
the number of interval pulses indicating the number of stations
between the vehicle location and the vehicle destination occurring
between the occurrence of the first of the location signal pulse or
the destination pulse for controlling the driving means to move the
vehicle at a high selected velocity when the number of said
interval pulses is greater than a first selected number, to move
the vehicle at an intermediate selected velocity when the number of
interval pulses is equal to or fewer than said first selected
number and greater than a second selected number, and to move the
vehicle at a low selected velocity when the number of interval
pulses is equal to or fewer than said second selected number.
22. A vehicle control system according to claim 20 also comprising
a destination sensing means responsive to the simultaneous
occurrence of the location signal pulse and the destination signal
pulse for indicating that the vehicle is at the selected
destination station.
23. A vehicle control system according to claim 15 wherein said
location means comprises a location sensing means connected to the
vehicle and adapted to respond to the unique designation signal at
the station at which the vehicle is located for producing a vehicle
location signal indicating the location of the vehicle at said
respective station; and a location indicating means correlated to
and responsive to the pulse means pulses and the vehicle location
signal for producing a location signal pulse upon the occurrence of
the pulse means pulse corresponding to the station indicated by
said vehicle location signal.
24. A vehicle control system according to claim 15 wherein said
destination means comprises a means for producing a destination
signal indicating the selected vehicle destination; and a
destination indicating means correlated to and responsive to the
pulse means pulses and the destination signal for producing the
destination signal pulse upon the occurrence of the pulse means
pulse corresponding to the selected vehicle destination.
25. A vehicle control system according to claim 15 wherein said
control means comprises a direction means responsive to the
sequence of occurrence of the location signal pulse and the
destination signal pulse for controlling the driving means to move
the vehicle in the direction corresponding to the sequence of
occurrence of said signal pulses and thereby in the direction
toward the station selected as the destination station.
26. A vehicle control system according to claim 15 wherein said
control means comprises an interval sensing means adapted to count
the number of interval pulses occurring between the occurrence of
the location signal pulse and the occurrence of the destination
pulse for controlling the driving means to move the vehicle at a
higher selected velocity when the number of said interval pulses is
greater than a selected number and to move the vehicle at a lower
selected velocity when the number of interval pulses is equal to or
fewer than said selected number.
27. A vehicle control system according to claim 15 wherein said
control means comprises an interval sensing means adapted to count
the number of interval pulses indicating the number of stations
between the vehicle location and the vehicle destination occurring
between the occurrence of the two signal pulses for controlling the
driving means to move the vehicle at a high selected velocity when
the number of said interval pulses is greater than a first selected
number, to move the vehicle at an intermediate selected velocity
when the number of interval pulses is equal to or fewer than said
first selected number and greater than a second selected number,
and to move the vehicle at a low selected velocity when the number
of interval pulses is equal to or fewer than said second selected
number.
28. A vehicle control system according to claim 15 also comprising
a destination sensing means responsive to the simultaneous
occurrence of the location signal pulse and the destination signal
pulse for indicating the location of the vehicle at the selected
destination station.
29. A vehicle control system having a vehicle movable to a
plurality of stations along a selected path comprising:
a driving means for moving the vehicle along the path and for
stopping the vehicle at selected stations,
a designation means for producing a unique designation signal for
each respective station,
a remote control center and a main control center with only one of
said centers located on the vehicle,
a master pulse generating device producing a continuous series of
pulses located in the main control center,
a slave pulse generating device producing a continuous series of
pulses located in the remote control center,
a main counting circuit located in the main control center adapted
to receive pulses from the master generating device and to define
the pulses in groups of pulses correlated by sequence of occurrence
to the sequence of position of the stations,
a remote counting circuit located in the remote control center
adapted to receive the pulses from the slave pulse generating
device,
a synchronizing means located in the main control center for
synchronizing the outputs of the main and remote counting
circuit,
a location means on the vehicle responsive to the designation
signal at the station at which the vehicle is located and to the
main counting circuit pulses for producing a location signal pulse
upon the occurrence of the pulse corresponding to said station
thereby indicating the location of the vehicle at said respective
station;
a destination means for producing a destination signal pulse upon
the occurrence of the pulse corresponding to the selected vehicle
destination thereby indicating the selected vehicle destination,
and
a direction means responsive to the location signal pulse and the
destination signal pulse for controlling the driving means to move
the vehicle in the direction corresponding to the sequence of
occurrence of said two signal pulses and thereby in the direction
toward the station selected as the destination station, whereby
said vehicle is moved by said driving means to said destination
location.
30. A vehicle control system according to claim 29 wherein said
designation means comprises coded groupings of magnets at each
station; and said location means comprises a sensing device located
on the vehicle adapted to respond to the coded magnet group at the
station at which the vehicle is located for producing a unique
vehicle location signal in response to said coded magnet group; and
a count coincidence detector located on the vehicle and responsive
to the main counting circuit pulses and the vehicle location signal
for producing the location signal pulse upon the occurrence of the
pulse corresponding to said station.
31. A vehicle control system according to claim 29 wherein said
control means comprises a switching circuit responsive to the
sequence of occurrence of the signal pulses to provide a power
source of one polarity if the location signal pulse occurs first
and of the other polarity if the destination signal pulse occurs
first; means responsive to the polarity of the source to control
the direction of movement of the vehicle in response to said
polarity; a pulse counter adapted to count the number of interval
pulses occurring between the occurrence of the signal pulses to
produce one output when the number of said interval pulses is
greater than a selected number and to produce another output when
the number of interval pulses is equal to or less than said
selected number; and means responsive to the pulse counter outputs
to control the driving means to move the vehicle at one velocity in
response to one of said pulse counter outputs and at another
velocity in response to the other of said pulse counter outputs.
Description
This invention relates to control systems for vehicles
automatically movable to selected destinations, particularly to
control systems for material handling vehicles in material unit
handling and storage systems.
In material handling and storage systems that store material units
in bins arranged in columns and rows, stacking vehicles that travel
on tracks within the aisle between the columns of bins are often
used to transfer material units into and out of the bins. The
stacking vehicle typically has an elevator with a laterally movable
platform adapted to pick up and deposit individual material units
in the bins and at the receiving and depositing home station. A
vehicle position sensing system of some type provides information
for controlling movement of the vehicle within the aisle and may
use electrical, mechanical magnetic or other sensing devices on the
vehicle that sense coded signal devices located adjacent
corresponding bin column locations.
With this invention, a vehicle control system is provided that
enables moving the vehicle at various speeds between stations and
that provides for automatically maintaining positive control of the
vehicle and information of its location and destination at all
times. The system continually keeps track of the location of the
vehicle and its destination and is moved at a speed depending on
its distance from its destination. The system uses a remote control
arrangement having a simple data link between the stationary and
the movable portion of the system.
Objects and advantages of this invention will be apparent from the
following detailed description.
FIG. 1 is a simplified end view of a material unit handling and
storage system embodying this invention having a load storage
structure and a stacking vehicle movable within the aisle formed by
the storage structure;
FIG. 2 is a top view of a portion of the system shown in FIG. 1
more clearly showing the location of sensing device groups
according to this invention;
FIG. 3 is a schematic drawing of a portion of the logic control
system for controlling the movement of the vehicle;
FIG. 4 is a schematic drawing of another portion of the logic
control system; and
FIG. 5 is a schematic representation of the relationship of the
sensing devices on the stacking vehicle and the coded magnetic
strips at the bin locations or stations.
FIG. 6 is a time sequence showing of the output of the
multivibrator, the counters, and certain of the logic elements.
Referring to FIGS. 1 and 2, a material unit storage and handling
system comprises a load storage structure 10, a stacking vehicle
11, a driving means 13 for moving the stacking vehicle, and a means
for controlling the driving means as shown in all the figures. Load
storage structure 10 comprises bin assemblies, such as a bin
assembly 15 and a bin assembly 16, forming an aisle 20 and bin
columns or loading stations 22A through 22F. Bin assemblies 15 and
16 are similarly constructed with vertical support posts 24 and
lattice 26 strenghtening and supporting the vertical posts and with
horizontal beams 27 forming the base of each of the bins for
receiving the material units. Stacking vehicle 11 is movable to
plurality of stations 22A through 22F along a selected path defined
by aisle 20 and tracks 28 and has a vertically and laterally
movable elevator 30 adapted to move material units, such as a
material unit 31, into and out of the bins formed by bin assemblies
15 and 16. Stacking vehicle 11 rides within aisle 26 on wheels 32
and tracks 28 and has a base structure 33 and a superstructure 35
for carrying elevator 30.
The driving means for moving the stacking vehicle may be of any
known type and may comprise a drive assembly 40, shown in
simplified form, having a motor 41 mounted on base structure 33 of
the vehicle and connected to drive an axle 42 and wheels 32 over
tracks 28 through a power coupling assembly 43. Power for motor 41
is obtained from an electrical power source (not shown) through a
connecting device 45 connected to the power source through a
connecting channel 46 in any known manner.
The means for controlling the driving means comprises a designation
means for producing a unique designation signal for each respective
station, a pulse means for producing groups of pulses, a location
means for producing vehicle location signal pulses, a destination
means for producing destination signal pulses, and a control means
for controlling the driving means to move the vehicle in a selected
direction.
The designation means comprises a signal device at each station,
such as coded magnetic assemblies or devices 48A through 48F, as
schematically shown in FIG. 5 and partially shown in FIG. 2, each
adjacent a respective station and each producing a unique
designation signal correlated to the respective adjacent bin
columns or station. Each of coded devices 48A through 48F comprises
a location coded magnetic strip such as magnetic strips 50A through
50F that correlate to adjacent stations 22A through 22F,
respectively, as shown in FIGS. 2 and 5, strobe magnets 52, one at
each station, that are used to indicate that the vehicle is at a
station and that location information is available, and centering
magnets 54, one at each station, that are part of a fine
positioning means for stopping the vehicle accurately at its
destination.
Referring to FIG. 3, the pulse means comprises a pulse generator
means for producing a continuous series of pulses and a counting
means for producing the defined groups of pulses by grouping the
pulse generator means pulses. The number of pulses in each defined
group is equal to or greater than the number of vehicle stations so
that there is a pulse for every station. Therefore, at least some
of the pulses each respectively correspond to a respective
station.
The pulse generator means may comprise multivibrators 61 and 62,
with a remote control center, designated by dotted block 60, with
multivibrator 61 as a master pulsing device, and multivibrator 62
as a slave pulsing device. Remote control center 60 would typically
be stationary with most of the rest of the system as shown located
on the vehicle to enable the use of only two data links along
conductors 64 and 65. The system components are placed at
convenient places on the vehicle as in a cabinet 12 as shown in
FIGS. 1 and 2, with appropriate conductors (not shown) to the
various parts of the control system, and to connecting device 45.
Data link conductors 64 and 65 carry information coupled along with
power through connecting device 45 and connecting channel 46. The
pulses from multivibrators 61 and 62 are respectively applied to
the counting means that comprises a master counter 67 and a slave
counter 68 which receive the pulses and define the pulses as groups
that are correlated by sequence of occurrence to the sequence of
position of the stations in any known manner, typically with a
digital unit counter and a periodic starting pulse when a counter
is "filled."
The outputs of the counters are applied to a synchronizing circuit
69 of any known type that compares the phase relationship of the
pulses and the starting pulse to control slave counter 67 and
possibly slave multivibrator 61 to insure synchronization at the
start of each group of pulses and for the pulses of both counters.
A single multivibrator and a single counter can be used if a simple
data link is not desired.
The location means comprises a location sensing means for producing
a vehicle location signal and a location indicating means for
producing the location signal pulses upon the occurrence of the
counter output pulse corresponding to the station at which the
vehicle is located. The location sensing means includes a switch
group 70 mounted on switch assembly 71 on vehicle 11, as shown in
FIGS. 1 and 5, that is in a position to respond to the magnetic
coded signals of the designation means as the vehicle moves along
its path. Switch group 70 comprises reed switches 72 or similar
devices responsive to the magnetic signals to selectively close in
response to the coded magnets 50A through 50F to produce a signal
indicating the vehicle location. The information from switches 72
is manipulated in any known manner to provide an appropriate input
signal 75 (FIG. 3). A reed switch 76 responds to strobe magnets 52
to provide an input for a logic control circuit along line 72A.
The location indicating means comprises a count coincidence
detector 78 that receives the input signal from input 75 and
produces an output along line 79. Coincidence detector 78 is a
device of any known type that produces a digital signal at the
particular pulse in a group of pulses that in this embodiment
corresponds to the appropriately coded input signal pulse
indicating the vehicle location. The location indicating means and
the location sensing means, therefore, respond to the designation
devices at the station at which the vehicle is located either while
moving or not moving, to produce the vehicle location signal that
indicates the location of the vehicle. The location signal is
correlated to the counting means output in count coincidence
detector 78 to produce the location signal pulse upon the
occurrence of the counter output pulse corresponding to the station
indicated by the vehicle location signal.
Similarly, the destination means comprises a means for producing a
destination signal that includes an input, shown diagrammatically
as input 85, for indicating the selected vehicle destination from
punch processing card systems, manipulation of switches, or other
similar known devices; and a destination indicating means that
includes a count coincidence detector 88 that receives the groups
of pulses from counter 67 and produces a digital signal at the
pulse corresponding to the selected destination in the same manner
as the location means. Coincidence detector 88 produces the
destination signal pulse upon the occurrence of the output pulse
corresponding to the station selected as the vehicle destination
along line 65.
Accordingly, the location signal pulse from coincidence detector 78
is applied along line 79 and the destination signal pulse from
coincidence detector 88 is applied along line 65 to the control
means. The control means comprises a driving control means 80 (FIG.
4) of any known type, as, for example, an electrical servo system
that controls drive assembly 40, to move the vehicle in the
direction towards the station selected as the destination station
and at the velocity determined by the distance from the destination
station in response to the two signal pulses. The control means
also comprises a direction indicating means responsive to the
sequence of occurrence of the signal pulses, which indicates the
direction the vehicle must move, and controls the driving means
through driving control means 80 to move the vehicle in the
direction corresponding to the sequence of occurrence; and an
interval-sensing means for controlling the driving means through
driving control means 80 to move the vehicle at selected
velocities.
The direction indicating means, FIG. 3, comprises a first flip-flop
circuit 101 and a second flip-flop circuit 102 that are set by the
signal pulses along lines 79 and 65 from coincidence detectors 78
and 88, and a polarity control circuit 105 having a relay 106 and a
relay 107. Depending on which coincidence detector output occurs
first, which is correlated to the time relationship of the pulses,
one of the particular flip-flops is set to produce an output at its
upper output terminal 01 101A or 102A and thereby energize either
relay 106 which has a winding 106W and a normally open contact 106A
or relay 107 which has a winding 107W and a normally open contact
107A. The contacts are connected in a circuit having a power source
109 with a positive terminal 110 and a negative terminal 111, and
depending upon which of the contacts closes first, apply a
potential of a selected polarity either through a resistor 113 or a
resistor 114 indicating the direction that the vehicle is to move.
This output is applied along a line 115 to the driving control
means which controls the driving means accordingly and moves the
vehicle in the appropriate direction.
The interval sensing means also receives the two signal pulses
along lines 79 and 65 and comprises flip-flop circuits 101 and 102,
AND-gates 117 and 118 connected to receive the outputs of flip-flop
circuits 101 and 102; an OR gate connected to receive the outputs
of AND gates 117 and 118; and AND-gate 120 connected to receive the
pulses from multivibrator 62, an input along line 82 from any
source indicating that the system has been energized, and strobe
input 72A from strobe switch 76 which senses strobe magnet 52
indicating that the vehicle is adjacent a location and therefore in
a position to sense coded magnets 50A through 50F; a ripple counter
125; and a speed selection circuit 127 (FIG. 4) that provides the
input signals to the driving control means to control the vehicle
speed.
Ripple counter 125 is of any known type and in this embodiment has
three counting circuits 130, 134, and 138 each of which has AND
gate circuits 131, 135 and 139, respectively, and flip-flop
circuits 132, 136 and 140, respectively. The flip-flop circuits
change state upon receiving a set or counting input at an input
terminal C and produce an output at terminals 133, 137 and 141 only
when this terminal is switched from an "on" state to an "off"
state. This output pulse is sent to the AND gate of the following
counting circuit and it performs a counting function. The flip-flop
circuits are reset by an input to their R terminals. Ripple counter
125 also comprises six AND gates 151 through 156. An inverter 145
provides an input to AND gate 131 of initial counting circuit 130
from AND gate 156. Ripple counter 125 thereby provides three
different output conditions at lines 160, 161 and 162 that are used
to indicate a high, intermediate and low speed requirement for
movement of the vehicle.
The control means also comprises a destination sensing means for
producing a destination output signal that comprises an AND gate
159 that receives the signal pulses from coincidence detectors 78
and 88 along lines 79 and 65, respectively. Upon simultaneous
occurrence of the location signal pulse and the destination
indication pulse, an output is produced along line 163.
This output is applied to the speed selection circuit to control
the final movement of the vehicle in response to a fine positioning
means 198 for stopping and positioning the vehicle at its
destination that comprises centering magnets 54 and a centering
switch 77 that responds to the magnets to finally position the
vehicle at the destination and may be of any type that produces an
appropriate signal to enable a servo system or similar system as
driving control means 80 to accurately stop and position the
vehicle.
The speed selection circuit (FIG. 4) receives inputs along
conductors 160, 161, and 162 from ripple counter 125 and along
conductor 163 from AND-gate 159 and applies this input into a logic
component group having OR-gates 170, 171, 172 and 173; flip-flop
circuits 176 and 177 responsive to the OR gate outputs; and AND
gates 180, 181, 182 and 183 having outputs along lines 190, 191,
192, and 193, respectively. A power set input 165 is also provided
to the OR gates to reset the flip-flop circuits to a position
turning on AND-gate 183 to produce an output at conductor 193 to
the driving control means to cause movement of the vehicle at the
very slow fine positioning velocity.
In the operation of the system, vehicle 11 is moved from station to
station as required to transfer material units. Upon the
determination that the vehicle should move from its present station
to a destination station, the system is activated by selecting a
destination for the vehicle and by applying an energization or "go"
input 82 to AND-gate 120 (FIG. 3). Multivibrator pulse generators
61 and 62 and counters 67 and 68 produce the defined groups of
pulses that are correlated to the physical location of the stations
available to the stacking vehicle. If the vehicle is at a station
as is typically the case, strobe input 72A is also applied to
AND-gate 120. If no strobe input is present, interlocking switching
circuits (not shown) would energize power reset line 165 in speed
selection circuit 127 (FIG. 4) and operate the vehicle at very slow
velocity until a station was reached at which time the vehicle
location would be "known" to the system. Coincidence detectors 78
and 88 produce the signal pulse outputs which indicate the
direction of vehicle movement. The occurrence of the first counting
pulse for each of the defined groups of pulses and the pulses are
synchronized by synchronizing circuit 69 by controlling slave
multivibrator 62 and slave counter 68. The coincidence detector
signal pulses are received by flip-flop circuits 101 and 102 which
are reset at the beginning or end of each cycle or group of pulses
by a reset signal from counter 68 along a line 66. The setting of
one of the flip-flop circuits energizes relay 106 or 107 closing
either contact 106A or 107A to provide a polarity output to driving
control means 80 along line 115 that causes vehicle movement in the
direction towards the destination station.
The setting of one of flip-flop circuits 101 or 102 also activates
AND-gate 117 or AND-gate 118. Counting circuit 130 of ripple
counter 125 then receives a signal from OR gate 119 along a line
131B and from AND-gate 120 along a line 131A at each pulse if a
strobe signal is present along line 72A and an energization signal
along line 82. AND-gate 131 of counting circuit 136 also receives
an input signal along a line 131C through inverter 145 because
AND-gate 156 of ripple counter 125 does not have an output at this
time. The counting circuits of the ripple counter are automatically
reset at the beginning of each group of pulses by the reset pulse
received along line 66. The ripple counter receives pulses and
counts the pulses during the interval between the two signal pulses
until the second of flip-flop circuits 101 or 102 is set which
turns off AND-gate 117 or 118, whichever is on, and thereby turns
off OR-gate 119. The counting of the pulses ends with one AND gate
of AND-gates 151 through 156 turned on. With one, two or three
interval pulses AND gate 151, 152, or 153 is turned on to produce a
signal along line 162, with four or five interval pulses AND gate
154 or 155 is turned on to produce a signal along line 161, and
with six or more interval pulses AND-gate 156 is turned on to
produce a signal along line 160 which also is an input to inverter
145. The input to inverter 145 upon the count of the sixth pulse
inactivates ripple counter 125 because the output of inverter 145
turns off AND gate 131 of counting circuit 130. The counting
repeats for each counting cycle as long as a strobe signal is
present and information is always updated at each intermediate
station as the vehicle moves toward a destination station.
When the vehicle arrives at its destination, the two signal pulses
occur along lines 79 and 65 simultaneously to turn on AND-gate 159
and to produce the fine positioning output along line 163. The
inputs are applied along lines 160, 161, 162 and 163 to speed
selection circuit 127 (FIG. 4). The input along line 160 is a high
speed signal that turns on OR gates 170 and 172 to set flip-flop
circuits 176 and 177 to turn on AND-gate 180 and provide a high
speed signal along line 190 to driving control means 80. The input
along line 161 is an intermediate speed signal that turns on OR
gates 170 and 173 to set flip-flop circuit 176 and reset flip-flop
circuit 177 to turn on AND-gate 181 and provide an intermediate
speed output along line 191 to driving control means 80. The input
along line 162 is a slow speed signal that turns on OR gates 171
and 172 to reset flip-flop circuit 176 and set flip-flop circuit
177 to turn on AND-gate 182 and provide a slow speed signal along
line 192 to driving control means 80. Any speed selected continues
until a change of input occurs to change the conditions of the
flip-flop circuits. The input along line 163 is a fine positioning
speed signal that turns on OR gates 171 and 172 and resets
flip-flop circuits 176 and 177 to turn on AND-gate 183 and provide
a fine positioning speed signal along line 193 to driving control
means 80 and driving control means 80 then is responsive to the
output of fine positioning means 198 obtained from centering switch
77 to stop the vehicle at the selected location.
SIMULTANEOUS TIME SEQUENCE ELECTRICAL OUTPUTS
FIG. 6 is a plot of the signals at the various points indicated by
letters on FIG. 3. In this chart, time sequence is plotted
horizontally, while the simultaneous signals at various parts of
the circuit are shown vertically. The letter designations at the
left of the chart correspond to the lettered points shown in FIG.
3. In the preferred form of this circuit, the multivibrator signal
has a frequency of 100 kilohertz, and the counters each have 11
output conductors and can count up to 256 in binary numbers. In
other words, the counters count to 256 almost 400 times per second.
For illustrative purposes, and to maintain simplicity, chart 6
illustrates counters with four output conductors capable of
counting up to 16 in binary numbers.
Referring to FIGS. 3 and 6, 61 is a free-running master
multivibrator, while 62 is a slave multivibrator synchronized with
the master multivibrator 61 by means of a reset pulse generated at
the end of each counting sequence through the synchronizing circuit
69. The output of 61 and 62 are, for all practical purposes,
identical and is indicated as A in both FIGS. 3 and 6. In the
illustration at the top of FIG. 6, A is shown as a repeating pulse
with 16 pulses to a counting cycle (as mentioned above, the actual
preferred form has 256 pulses to this cycle). The pulse output from
61 is fed into a master binary counter 67, while the pulse output
from 62 is fed into a similar counter shown as slave counter 68.
The outputs of these two counters are identical, and is shown in
both FIGS. 3 and 6 as B. For illustrative purposes, we have shown
four conductors which permit counting to 16 in binary numbers. They
are labeled B1, B2, B3, and B4 in FIG. 6. These counters count up
through 16 and are then reset and start counting over again. They
each comprise a group of flip-flop circuits so arranged that they
are indexed by each pulse from the multivibrator. Referring to FIG.
6, pulse 1 causes current to flow in B1; pulse 2 carries current to
flow in B2, but not in B1; pulse 3 causes current to flow in both
B1 and B2; pulse 4 causes current to flow in B3, but not in any of
the other conductors. This continues as shown in FIG. 6 in such a
manner that the voltage or current in these conductors creates
binary number groups. Referring to FIG. 3, 75 schematically
indicates the pickup 71 and is actuated by individual stationary
arrays 48A, 48B, 48C, 48D, 48E, 48F, etc. The switching array on 71
"reads" the magnetic array 48A, etc., located at each bin location
so as to provide an electrical output in the conductors leading
from 75 to 78 which may be read as a binary number. Here again, for
illustrative purposes, we have indicated a four wire system which,
with various combinations of energization, can be read as a binary
number up to 16. (In the preferred embodiment, we use eleven
conductors which may be read by various combinations of voltage to
binary numbers up to 256.) For simplicity in illustrating, we show
four conductors which, by various combinations of voltages, may
read binary numbers up to 16. In other words, in such a simplified
version used for illustrative purposes, the bin position address
would be numbered from 1 to 16. To illustrate this, we have assumed
that the stacker is presently at position 4. In this position, we
would, of course, have an electrical voltage in conductor C3, and
no voltage in the other conductors, C1, C2 and C4. The output from
75 is compared with the output from 68. As the counter 68 counts in
binary numbers up to 16, there would be coincidence between the
conductors energized by 68 and those energized by 75 at the number
4. Referring to FIG. 3, the output from 78 through the conductor 79
is shown at B. Referring to FIG. 6, the sequence of voltages at D
is shown to be zero except at No. 4 where a pulse appears each time
the slave counter 68 counts through four in its cycle.
Referring again to FIG. 3, 85 is a schematic showing of the
destination indicator. The output of this indicator is in binary
code, and for illustrative purposes, we have indicated four
conductors so that it is possible to introduce a destination
command from 1 up to 16. For illustrative purposes, we have
indicated a command of position address 8 and referring to FIG. 6,
this shows electric voltage E4, but in none of the other
conductors. Here again, as described in connection with 68 and 78,
the same comparing of binary numbers in the form of voltages is
accomplished. Here, the master counter 67 again counts from 1 to 16
as energized by the pulses from the multivibrator 61. In FIG. 6,
the output of the multivibrator is shown as the A signal and the
output of the master counter 67 is shown as signals B1, B2, B3, and
B4. The output of the destination command indicator 85 is shown as
E1, E2, E3, and E4, with E4 energized, thereby indicating by binary
number the destination address 8. Here again, when there is
coincidence or matching between the signal from 85 and the signal
from 67, a pulse is generated by 88 which is fed out through the
line 65 as the signal F. Referring to FIG. 6, there is an
indication that no signal is generated at F except at the point
8.
The pulse D coming through line 79 energizes the flip-flop circuit
102 to turn it on and thus a DC signal G is generated in 102A
starting at pulse 4 and continuing through the cycle of counting
until a reset pulse is generated in 66 to reset the flip-flop
circuit 102. The signal output G is, therefore, zero until count 4,
and then is a positive signal through the remainder of the counting
sequence.
The pulse F in line 65, from the detector 88, likewise triggers the
flip-flop circuit 101 by energizing the set terminals to generate
the signal H which starts at the pulse 8 of the multivibrator and
continues through the counting sequence until the reset pulse at
the end of the sequence energizes terminal R of the flip-flop
circuit 101.
The direction signal I in the line 115 is controlled by switches
106A and 107A which, in turn, are controlled by the direction
control switch shown generally as 105 and including 106 and 107.
The selection of the switch to be closed, and thereby the selection
of the polarity of the signal is determined by the sequence of
occurrence of the signals H and G. In the signal sequence shown in
FIG. 6, the signal G appears first and, therefore, the switch 107A
will be closed and signal I will be a positive signal, which
through the control system, tells the stacker to proceed from
position 4 toward position 8.
Once switch 107A is closed, any signal from H is ineffective to
close 106A and 107A remains closed until a signal appears in which
signal H appears in the cycle previous to signal G. When H appears
before G does, then switch 107A is opened and switch 106A is
closed, thus giving the power drive a negative signal which drives
the stacker toward lower numbered bin addresses.
Gates 117 and 118, being "AND" gates, with 119 an "OR" gate, a
signal J appears when there is a signal H in the line 101A and not
a signal in 102A, or vice versa. Therefore, the signal J appears
when there are pulses between position No. 4 and position No. 8 in
our illustration (FIG. 6). The circuit 125 counts the number of
pulses received from the slave multivibrator 62 while a signal is
appearing at J in line 131B. If over six pulses appear, a signal is
generated in line 160 to drive the stacker at high speed. The gate
154 is energized if there are four pulses, and the gate 155
energized if there are five pulses. Therefore, if either four or
five pulses appear during the time a signal J is impressed in the
line 131B, a stacker is controlled on intermediate speed through
the line 161. Likewise, the gate 153 is energized by three pulses,
152 by 2 pulses, and 151 by one pulse. Therefore, if either one,
two or three pulses appear while there is a signal J in 131B, the
stacker is driven at low speed. As will be seen by FIG. 6, the
number of pulses generated during this interval indicates the
number of bins between present position and command position. The
stacker starts to slow down at five bin positions away from command
position and goes into low speed at three bins away from
destination. When the signal D and signal F appear at the same
time, this indicates the stacker is at command position and the
final positioning is accomplished through energization of the line
163 with lines 160, 161, and 162 being deenergized.
While this specification contains a written description of the
invention and the manner and process of making and using it and
sets forth the best mode contemplated of carrying out my invention,
there are many variations, combinations, alterations and
modifications of the invention that can be made within the spirit
of the invention and the scope of the appended claims.
* * * * *