Note: Descriptions are shown in the official language in which they were submitted.
CA 02588269 2007-05-09
METHOD AND APPARATUS FOR PATTERNED TURF CUTI'ING
This invention is in the field of turf mowing apparatuses and methods and more
panicularly ta a method and apparatus for automatically guiding a mower in
order to cut
a pattem into the turf of a field.
BACKGROUND
to Golf course, baseball fields and other sporting fields have large expanses
of lawn or turf
and it has become popular to cut these large areas into a pattern to provide a
more
professional appearing turf surface. In the simplest patterns, this pattemed
turf cutting
can consist of parallel stripes mowed into the lawn surface where the color of
the grass
alternates between adjacent stripes. More complex pattems involve checkerboard
and
0 diamond patterns and it is not uncommon to find even more complex cuts
involving
curves and other cuts.
These pattem.s appear as alternating colorcd "stripes" caused by the light
reflecting off of
the blades of the grass. When a blade of grass is bent away from a view, light
reflects off
20 the wide, lengthy part of the blade of grass, causing the blade of glass to
appear lighter in
color. Therefore, a stripe or row of mown grass that is bent away a viewer
will appear
lighter. When a blade of grass is bent towards a viewer, more of the tip of
the grass is
facing the viewer causing less reflective surface of the grass blade to be
facing the viewer
CA 02588269 2007-05-09
and the stripe of grass well appear darker to the viewer. Therefore, a stripe
or row of
mown grass that is bent towards a viewer will appear darker than a stripe or
row of mown
grass that is bent away from the viewer. By alternating the direction grass is
bent in
adjacent stripes or rows, the appearance of alternating stripes of lighter and
darker grass
can be achieved and this is what allows a person mowing the grass to create a
pattetn in
the mown turf.
To form these stripes or rows, lawn or turf is bent in a specific direction by
mowing it in
that direction. By alterrtating the direction that grass is mowed in, i.e. one
stripe mowed
io in a north direction and an adjacent stripe mowed in a south direction, the
appearance of
different colored stripes is achieved.
Mowers equipped with mower reels tend to bend the grass being cut in a single
direction
as a result of the operation of the cutting reel, however, it is also cornmon
for a mower to
be equipped with a lawn striper tool to further bend the stalks of grass in a
particular
direction. As opposed to a cutting blade that bends the grass stalks in
conjunction with
cutting the grass stalks, a lawn striper simply further bends the stalks of
grass towards the
ground enhancing the appears of striping in the grass surface.
While the principles and theory behind cutting a grass surface into a pattern
is well-
known, the implementation of it is hardly easy or straightforward. In theory,
all it
requires to cut a pattem into a field surface is to mow the field surface in
alternating
directions. However, in practice, it is much more complex and difficult than
this. Often,
CA 02588269 2007-05-09
highly expcrienced cutters are necessary to get the pattern just right and it
is typically
oniy exclusive or professional fields that presently use patterned turf
cutting, such as
major league baseball fields and upscale golf courses.
There are a number of reasons why pattemed turf cutting is presently not
conunon on
more sporting and other fields. While on smaller fields in may be easier to
achieve
relatively straight lines, when the cutting patterns are applied to relatively
large fields
such as golf courses and baseball fields it is quite difficult to keep the
lines straight
enough so that the lines do not appear wavy. While applying the pattern to a
large field
greatly enhances the appearance of the pattern, it creates some problems with
getting the
"stripes" or pattetn looking straight. Small deviations in a straight cutting
line will often
mar the whole effect and by a cutter who accidentally deviates from a straight
line can
often adversely affect the "profe,ssional" look of the pattem. In addition,
because an
operator of a mowcr tcnds to follow the lines of a prcvious cutting path,
small deviations
in a first path can cause serious deviations in later adjacent paths, where
the operator has
used the first path as a guide for cutting the adjacent paths. It takes a very
experienced
cutter to be able to drive a mower in a straight line in order to achieve the
pattem and
often the cutter must concentrate fairly intensely for long periods of time to
get the
pattern to appear straight because with such large mown turf surfaces evcn
relatively
2o small deviations can mar the overall effect of the pattern.
Additionally, when the patterns become more complex it is often hard for an
operator of a
mower to determine where exactly he or she is on the pattem. While from a
bird's eye
CA 02588269 2007-05-09
view or standing at one end of a field, it is easy to visualize the overall
cutting pattem in a
field, it is often quite difficult if not impossible for an operator of a
mower in the middle
of the field to figure out where in the pattern he or she is and where he or
she should go
frorn any given spot. This problem is exasperated by the fact that that bent
blades of
grass often do not appear as vivid in the midst of them as they do when
standing at a
distance. A person standing on a stripe will not be able to see the stripe as
easily as a
person standing further away. Often the pattern around the mowers is barely
visible to
the operator of the mower, if he or she is even able to see the pattern at
all. This requires
an experienced cutter to visualize the "design" or pattern in his or her mind
when cutting
the grass stnface and to he able to guide the mower based on the memorized
design. This
is why patterns such as stripes, checkerboard and diamond are the most
commonly seen
cutting patterns, with pattems involving curvcs and more intricate cuts
reserved for
special occasions.
SUNLMARY OF THE IIVVENTION
It is an object of the present invention to provide a systent and method that
overcomes
problems in the prior art.
The present invention comprises a system and method for directing a mower
along a
cutting path wherein the cutting path will result in a predetermined pattem to
be cut into
the surface of a field.
CA 02588269 2007-05-09
A control system is provided that is operative to store a cutting path in its
memory.
When the mower follows the cutting path to cut a field, a pattern is cut into
the field, such
as altemating stripes, checkerboard or diamonds. The mower begins cutting a
field at a
starting point on the cutting path and as the mower progresses along the
cutting path, the
control system will repeatedly determine the position of the mower and compare
the
mower's actual position to the desired cutting path. If the mower has deviated
from the
cutting path, the control system will transrnit a correction control signal.
The correction
control signal will depend on whether the mower has deviated to the right or
left of the
1o desired cutting path. If the if the mower has deviated to the right of the
desired cutting
path the correction control signal will indicate that the mower must be turned
left to once
again follow the desired cutting path, and vice versa.
In a first embodiment of the invention, the control system is operatively
connected to an
automatic steering system. When the control system determincs that the mower
is
deviating from the desired cutting path, the correction control signal is
transmitted to the
automatic steering system and the mower is automatically steered in the
direction
necessary for the mower to once again follow the desired cutting path.
In a second embodiment of the invention, the control system is operatively
connected to a
user display comprising a left indicator light and a right indicator light.
When the control
system detcnnines that the mower is deviating frorn the desired cutting path
to the iight
of the desired cutting path, a correction control signal is transmitted to the
user display
CA 02588269 2007-05-09
and the left indicator light is lit to indicate to the user that he or she
should manually turn
the mower to the left to regain the desired cutting path and vice versa.
As the mower progresses along the cutting path the control system will
continue to check
the actual position of the mower against the desircd cutting path and when the
cutting
path has been completed the mower will be fmished mowing the field.
In this manner, the cutting paths can be generated so that by the mower
following the
cutting path a pattern such as altemating stripes, checkerboard, diamonds or
even a more
i0 intricate design can be mowed into the surface of the field. Rather than
requiring the
operator of the mower to attempt to keep the overall design in his or her
memory and
figuring out what paths to follow with the mower, in the first embodiment of
the
invention, the mower can be automatically steered by the control system to
make the
desired pattem or in the second embodiment of the invention, the operator of
the mower
is simply by directed by the control system how to steer to result in the
desired pattern.
The operator does not need to be able to visualize or even plan the design in
his or her
head. Rather, the design is cut in the surface of a lawn at the direction of
the c.~ontrol
systern.
2o DESCRIPTION OF THE DRAWINC'S
While the invention is claimed in the concluding portions hereof, preferred
embodiments
are provided in the accompanying detailed description which may be best
understood in
CA 02588269 2007-05-09
conjunction with the accompanying diagrams where like parts in each of the
several
diagrams are labeled with like numbers, and where:
Fig. 1 is a perspective view of a mower, as is commonly known in the art;
Fig. 2 is a schematic illustration of a conventional hydrostatic drive system;
Fig. 3 is a schematic illustration of an automatic steering system for a mower
with
a hydrostatic drive, in accordance with a first embodiment of the present
invention;
Fig. 4 is a schematic illustration of the automatic steering system of Fig. 3,
incorporated into the hydrostatic drive system of Fig. 2;
Fig. 5 is a schematic illustration of a control system in accordance with the
present invention;
Fig. 6 is a flowchart of a software process for creating a cutting path for
use in
guiding a mower along the cutting path to cut a field into a desired pattern;
Fig. 7 is an illustration of a sample of a field map representing a fairway on
a golf
course for use in the process illustrated in Fig. 6;
CA 02588269 2007-05-09
Fig. 8A illustrates an altemating stripe pattem;
Fig. 8B illustrates a checkerboard pattem;
Fig. 8C illustrates a diamond pattern;
Fig. 9 is a diagram a cutting path overlaid on a portion of a field map of a
fairway
wherein following ehe cutting path with a mower will rcsult in a diamond
pattern;
Fig. 10 is a schematic illustration of a conventional computer system;
Fig. 11 is a flow chart of a cutting path process for mowing a field in a
specified
cutting pattern; and
Fig. 12 is an illustration of a user display in accordance with a second
embodiment of the present invention.
DETAILED DES(.'RIPTION OF THE ILLUSTRATED EMB4DIME'.~1TS
Fig. 1 is a perspective view of a mower that can be used to implement a system
and
method in accordance with the present invention. Mower 10 is a typical
commercial
grass mower for cutting the grass on the fairways of golf courses and
comprises: a
1
CA 02588269 2007-05-09
number of cutting reels 12; a left drive wheel 14; a right drive wheel 16;
operator's seat
11; and steering controls 70.
Cutting reels 12 cut the grass to a desired length. The mower 10 is driven by
left drive
wheel 14 and right drive wheel 16, which are hydrostatically steered and
driven by a
hydrostatic drive (not shown). An operator sitting in the operator's seat I1
has access to
the steering controls 70 and can steer the mower 10.
The Conventional Hydrostatic Steering System of a Commercial Mower
Fig. 2 is a schematic illustration of a conventional hydrostatic drive system,
such as the
hydrostatic drive system that would be incorporated into mower 10, in Fig. 1.
The
hydrostatic drive system 50 comprises: a right hydraulic motor 44; a left
hydraulic motor
42; a right drive conduit 34; a right return conduit 36; a left drive conduit
32; a left return
conduit 37; a valve block 55; a tank 60; a pump 65 and steering controls 70.
In typical operation of the hydrostatic drive system 50, hydraulic fluid from
the tank 60
will be pressurized by the pump 65 and the pressurized hydraulic fluid routed
to the valve
block 55. From the valve block 55, this pressurized hydraulic fluid is routed
through the
right drive conduit 34 to the right hydraulic motor 44 to drive a right drive
wheel 16, as
shown in Fig. 1, connected to the right hydraulic motor 44. From the right
hydraulic
motor 44, the hydraulic fluid is routed back to the routing valve 55 through a
right return
conduit 36. To drive a left drive wheel 14, as shown in Fig. 1, the
pressurized hydraulic
fluid is routed through the left drive conduit 32, by the valve block 55, to
the left
CA 02588269 2007-05-09
hydraulic motor 42. From the left hydraulic motor 42, the hydraulic fluid is
routed back
to the routing valve 155 through the left return conduit 37.
An operator controls the mower by entering inputs into the steering controls
70. The
steering controls 70 controls the distribution of the flow of the hydraulic
fluid by the
valve block 55, as commonly known in the art. Based on the operator's steering
inputs,
the vaive block 55 varies the flow of pressurized fluid to the right wheel
hydraulic motor
44 and the left wheel hydraulic motor 42. When an equal flow of hydraulic
fluid is
provided to the right wheel hydraulic motor 44 and the left wheel hydraulic
motor 42, the
mower will move in a straight direction of travel. By increasing the flow of
pressurized
hydraulic fluid to the right wheel hydraulic motor 44, so that more hydraulic
fluid is
flowing to the right wheel hydraulic motor 44 than the left wheel hydraulic
motor 42, the
right wheel of the mower is rotated faster than the left wheel causing the
mower to tum to
the left. Steering the mower to the right is accomplished by increasing the
flow of
13 pressurized hydraulic fluid to the left hydraulic motor 42 relative to the
right hydraulic
motor 44.
Alternatively, the mower can also be tumed by reducing the flow of hydraulic
flow to
either the right hydraulic motor 44 or the left hydraulic motor 42. For
example, the
mower can be turned left by left by reducing the aniount of hydraulic fluid
flowing to the
left wheel hydraulic motor 42 causing the right wheel to rotate faster
relative to the left
wheel and thereby causing the mower to turn left.
CA 02588269 2007-05-09
The Auto-steering Components of the Steering System
Fig. 3 schematically illustrates an automatic steering system 100 for a mower,
in
accordance with a first embodiment of the present invention wherein the mower
is
automatically steered by a control system 300 over part of a cutting path or
an entire
cutting path by means of control signals received from the control systern
300. The
steering system 100 comprises: a left diverting conduit 102, a left tee
connection 103; a
right diverting conduit 104, a right tee connection 105; a control circuit
110; and a return
conduit 120. Generally, although not necessarily, a right flowrate valve 112
and left
flowrate valve 114 can also be provided to allow the flowrate of hydraulic
flow in the
1o right diverting conduit 104 and left diverting conduit 102 to be adjusted.
Fig. 4 is a schematic illustration of the automatic steering system 100,
illustrated in Fig.
3, incorporated into the hydrostatic drive system 50, illustrated in Fig. 2.
The left
diverting conduit 102 is operative to contain a flow of hydraulic fluid and is
connected
into the left drive conduit 32, typically using the left tee connection 103,
such that the left
divening conduit 102 is operative to divert a portion of a flow of hydraulic
fluid out of or
away from the left drive conduit 32 so that the portion of the hydraulic fluid
that is
diverted by the left divert conduit 102 does not drive the left hydraulic
motor 42. The
right diverting conduit 104 is operative to contain a flow of hydraulic fluid
and is
connected into the right drive conduit 34, typically using the right tee
connection 105,
such that the right drive diverting conduit 104 is operative to divert a
portion of a flow of
hydraulic fluid out of or away from the right drive conduit 34 so that the
portion of the
CA 02588269 2007-05-09
hydraulic fluid that is diverted by the right divert conduit 104 does not
drive the right
hydraulic motor 44.
The control circuit 110 is typically an open center solenoid valve operative
to control the
flow of hydraulic fluid through the right diverting conduit 104 and the left
diverting
conduit 102. The control circuit 110, in response a control signal from a
control system
300, can open a flowpath and route a flow of hydraulic fluid through either
the right
diverting conduit 104 or left diverting conduit 102 to the return conduit 120
and back to
the tank 60. Although Figs. 2 and 3 show the control circuit 110 as being
connected to
to both the right divcrting conduit 104 and the left diverting conduit 102, it
would be
understood by a person skilled in the art that there could be a separate
control circuit 110
for each of the right diverting conduit 104 and left diverting conduit 102 and
that a single
control circuit does not necessarily have to be used to control the flow
through both Ihe
right diverting conduit 104 and left diverting conduit 102.
The control circuit 110 could comprise one or more valves that simple open or
shut a
flow path through the control circuit 110 to the return conduit 120 and the
control circuit
110 simply routes hydraulic fluid flow through either the right diverting
conduit 104 or
left diverting conduit 102, for a period of time, to control the steering of
the vehicle.
Optionally, if the control circuit 110 simply either stops all flow of
hydraulic fluid in the
right diverting conduit 104 and the left diverting conduit 102 or opens a
fluid flowpath
for the right diverting conduit 104 or left diverting conduit 102, the right
flowrate valve
112 and left flowrate valve 114 could be used to adjust the flowrate of
hydraulic fluid
CA 02588269 2007-05-09
through the right diverting conduit 104 and left diverting conduit 102 when a
flow path is
opened by the control circuit 110, thereby adjusting the turning rate caused
by the
steering system 100. The right flowrate valve 112 and left flowrate valve 114
are
adjustable flowrate valves that can be adjusted for a set flow rate.
Typically, the right
flowrate valve 112 and the left flowrate valve 114 are manually adjustable
needle valves
allowing the flowrates in the right diverting conduit 104 and the left
diverting conduit
102 to be adjusted.
Alternatively, the control circuit 110 could comprise a proportional valve
system and the
control circuit 110 could be operative to allow varying amounts of fluid flow
through the
right diverting conduit 104 and the left diverting conduit 102.
The steering system 100 of the present invcntion allows a control systeni 300
to steer a
vehicle with a hydrostatic drive, independent of steering inputs from an
operator of the
vehicle. By inducing hydraulic fluid flow through the right diverting conduit
104,
hydraulic fluid flow is diverted away from the right hydraulic motor 44. By
reducing the
flow of hydraulic fluid to the right hydraulic motor 44, the rotational speed
of a right
wheel 16, as shown in Fig. 1, being driven by the right hydraulic motor 44 is
reduced and
the mower wili turn towards the right. Altematively by inducing hydraulic
fluid flow
through the left diverting conduit 102, hydraulic fluid flow is diverted away
from the left
hydraulic motor 42, which will in tutn reduce the flow of hydraulic fluid to
the left
hydraulic motor 42 and cause the mower to turn to the left.
CA 02588269 2007-05-09
Hydraulic fluid routed through the right diverting conduit 102 or left
diverting conduit
104, by the control circuit 110, is passed back through the return line 120 to
the hydraulic
fluid tank 60 where it can be rcturned to the pump 65 and reused in the
hydrostatic drive
system 50. Again, although Figs. 2 and 3 illustrate a single control circuit
110 controlling
the flow of hydraulic fluid through the right diverting conduit 104 and the
left diverting
conduit 102, if a separate control circuit was provided for each of the right
diverting
conduit 104 and left diverting conduit 102, a separate return line connected
to each of the
right diverting conduit 4 and the left diverting conduit 102 and retuming to
the tank 60
could be used, so that the right diverting conduit 104 and the left diverting
conduit 102 do
not have to be in relatively close physical proximity and connected to a
signal eontral
circuit 110.
The Control System
Fig. 5 illustrates a control system 300 in accordance with the present
invention, that is
operative to determine when a mower is deviating from a desired cutting path
and
transmit correction control signals in response to the mower deviating from
the desired
cutting path. Control system 300 comprises: a processing unit 310, such as a
microprocessor; a GPS receiver 320, operative to determine a position based on
GPS
signais; a memory 330, for storage of data; and an input/output interface 340.
Generally,
althouglt not necessarily the control system 300 can also incorporate a
gyroscopic
position unit 350 that uses gyroscopes to determine a direction of travel.
While Fig. 5
illustrates a control system 300 that uses a GPS receiver 320 to determine the
position of
CA 02588269 2007-05-09
the vehicle, it is contemplated that the control system 300 could use any type
of method
for dctermining its position such as dead reckoning, beacon referencing, etc.
The control system 300 is operative to compare an actual position of a mower
against a
desired cutting path stored in the memory 330 of the control system and
transmit
correction signals from the input/output interface 340 when the mower has
deviated from
the desired cutting path. As the mowcr is in operation, the control system 300
will
repeatedly receive GPS signals using the GPS receiver 320 and determine the
position of
the mower. The processing unit 310 will compare the determined position of the
vehicle
-o with the desired cutting path, to determine if the mower is following the
cutting path or if
the mower has deviated from the cutting path. Additionally, if the control
system 300
comprises a gyroscopic position unit 350, the processing unit 310 will be able
to
determine the direction of travel of the mower and predict whether the
direction of travel
will cause the mower to leave the desired cutting path.
When the control system 300 determines that the mower has left the desired
cutting path,
the control system 300 transmits a correction control signal in order to alter
the direction
of travel of the mower. Upon the processing unit 310 determining that the
mower is not
on or is leaving the cutting path, the processing unit 310 will determine
which way the
mower has to be steered to either keep following the desired cutting path or
to get the
mower back on the cutting path, and the processing unit 310 will send a
correction
control signal through thc input/output interface 340.
CA 02588269 2007-05-09
In a first embodiment of the invention, the correction control signal is
transmitted to the
stecring system 100, of Fig. 3, in order to automatically steer the mower back
to the
desired cutting path. The correction control signal is transmitted by the
control system
300 to the steering system 100 and to the control circuit 110. Depending upon
whether
the control system 300 determines that the mower is deviating from a desired
cutting path
in either a right or left direction, the correction control signal transmitted
to the control
circuit 110 will open a flow path for either the right diverting conduit 102
or left diverting
conduit 102, causing the mower to turn to either the left or right
respectively.
The correction control signal transmitted from the control system 300 to the
control
circuit 110 is typically in the form of a voltage input. When the control
circuit 110
receives a voltage input from the control system 300, the control circuit
opens a flow path
and causes hydraulic fluid to flow through either the right diverting conduit
104 or left
diverting conduit 102, until the voltage input stops. The control system 300
turns the
t5 vehicle to the right by sending a control signal to the control circuit 110
to open a
flowpath for the right diverting conduit 104, causing the right diverting
conduit 104 to
route a portion of the hydraulic fluid flow away from the right hydraulic
motor 44 and
tums the vehicle to the left by sending a control signal to the control
circuit 110 to open a
flowpath for the left diverting conduit 102, causing the left diverting
conduit 102 to route
a portion of the hydraulic fluid flow away from the left hydraulic motor 42.
Whcn the control system comprises a valve system that is either open or shut
valves, the
rate of tuming can be altered by the sizing of the valve or valves in the
valve system.
CA 02588269 2007-05-09
Using a larger valve or valves will divert more hydraulic fluid flow away from
the
hydraulic motors causing the vehicle to turn faster when the valves are
opened.
Alternatively, the right flowrate valve 112 and left flowrate valve 114 can be
uscd to
adjust the flowrate in the right diverting conduit 104 and the left diverting
conduit 102
thereby altering the flowrate of hydraulic fluid flow way from the hydraulic
motor and
allowing the turning rate of the steering system 100 to be adjusted.
Altcrnativcly, control circuit 110 can comprise a proportional valve or valves
operative to
open various amounts in response to control signals from the control system
300. For
example, these control signals can be digital signals or analog signals
specifying the
degree of opening of the valve that is desired, whereby the amount the
proportional valve
opens will he based on the control signal from the control system 300. In this
manner,
the control system 300 would also be able to control the flowrate of hydraulic
fluid
through the right diverting conduit 104 and left diverting conduit 102 and in
turn the
turning rate of the vehicle. When the vehicle is oi>ly slightly deviating from
the desired
path, the control system 300 may only open the proportional valve or valves a
slight
amount to turn the vehicle slowly. Alternatively, if the vehicle is deviating
significantly
from the desired path, the control system 300 could open the proportional
valve or valves
a greater amount to cause the rate of turning of the vehicle to be greater.
In a second embodiment of the invention, the correction control signal will be
transmitted
to a user display 700, illustrated in Fig. 12. The user display 700 comprises
a left
indicator light 710 and a right indicator light 720. Depending upon whether
the control
CA 02588269 2007-05-09
system 300 determines that the mower is deviating from a desired cutting path
in either a
right or left direction, the correction control signal transmitted to the user
display 700 will
indicate to an operator which way to steer the mower, by lighting the left
indicator light
710 or right indicator light 720, respectively. The user will then steer the
mower in the
indicated direction.
Referring again to Fig. 5, the control system 300 will continue to detennine
the position
of the mower in relation to the cutting path as the mower turns and once t.he
mower has
moved back to the cutting path the control system 300 will stop sending a
control signal
to to get the mower once again following the cutting path. Typically, a small
correction
signal operative to turn the mower in the opposit.c direction is required,
when the mower
is once again on the cutting path, in order to straighten out the mower on the
cutting path.
The cutting path stored in memory 330 of the control system 300 determines the
path of
travel followed by the mower. In the first embodiment of the invention, the
mower can
be automatically steered, by the control system 300, along relatively straight
parts of the
cutting path. When a sharp corner is approached, the control system 300 can
indicate to a
user to turn and an operator then uses the steering controls 70 to change the
direction of
the mower. Once the mower is once again facing a relatively straight part of
the cutting
path, the control system 300 resumes automatically steering the mower.
Alternatively,
the control system 300 could be given complete control of the mower, with the
control
system 300 steering the mower along the entire desired cutting path 330,
including any
CA 02588269 2007-05-09
relatively sharp turns, with the operator only required to intervene and use
the steering
controls 70 in the event of an emergency.
Creating a Cutting Path
For the mower to mow a pattern into the turf of a field, the cutting path must
be created
that will result in the desired pattem. Fig. 6 is a flowchart of a software
process 400 for
creating a cutting path for use in guiding a mower along the cutting path to
cut a field into
a desired pattern. Process 400 comprises the steps of: starting 405; loading a
map of thc
field into memory 410; determining a pattern 420; determining the number of
mowers
t0 430; overlaying cutting path on the field map 440; and finishing 450.
The method starts 405 and a map of the field to be cut is loaded into memory
410. The
field map will be a map of the field to be cut in accurate scaled dimensions
and
displaying any impediments in the field. It can either be selected from a
number of pre-
existing field maps in memory or it can be created and loaded for the first
time. For
example, if the field to be cut is a baseball diamond, the field map will show
the
dimensions of the outfield to scale along with the start of the infield, the
pitchers mound,
etc. If the field to be cut is a hole of a golf course, the shape of the hole
will have the
shape fairway to scale and indicate the cart path, any hazards such as sand
traps, water
hazards, etc., the grcen and any trccs or shrubs that may appear on the
fairway.
CA 02588269 2007-05-09
Fig. 7 illustrates a sample of a field map 460 representing a fair way on a
golf course.
Field map 460 will he rendered to scale and will indicate the relative
dimensions of the
fair way 465, any water hazards 470, sand trap 475, shrubs 480 and the green
490.
Referring again to Fig. 6, the next step will be to determine a cutting
pattertt 420. For
example, alternating stripes, checkerboard pattem, diamond pattem, etc. could
be chosen,
as illustrated in Figs. 8A, 8B and 8C, respectively. If these relatively
simple designs are
chosen, the pattem could be applied to the field in a repetitive manner until
the entire
field was covered. Alternatively, if the design is a more complex pattern, it
may be
i o custom designed for a field.
Next, the number of mowers is determined 430. One mower alone can be used to
cut the
fields. Altematively, more than one mower could be used to achieve the same
result
quicker. Additionally, one mower may be used for cutting and a second mower
may be
used without cutting blades, with only a striper toot to bend the grass.
Finally, the ctrtting pattem will be overlaid on the file map 440. A cutting
paths to be
followed by the mower will be determined using the cutting width of the
inower, the
dimensions of the field to be cut, the desired pattern to be cut by the mower
and the
number of mowers to be used. If the pattem selected is a relatively simple
pattem such as
aiternating lines, checkerboard or diamonds, the pattetn can be repeatedly
overlaid on the
field map. However, if the design is more complex or non-repeating, it may
have to be
superimposed on the field map in a large open area and optionally a repetitive
pattern
CA 02588269 2007-05-09
used to fill in the edges. If more than one mower is used, the cutting paths
will be
divided and each mower will be given half of the cutting paths so that both of
the mowers
cut a complete pattetn when working in conjunction.
Fig. 9 illustrates a cutting path overlaid on a portion of a field map of a
fairway wherein
following the cutting path with a mower will result in a diamond pattem. The
cutting
path with make a first cutting path 485 diagonal across the length of the
fairway and a
second cutting path 490 going diagonal in the other direction across the
fairway. By
having a mower follow the first cutting path 485 and then the second cutting
path 490 a
to diamond pattern will be mowed into the fairway. Alternatively, a first
mower can be
programmed with the first cutting path 485 and a second mower can be
programmed with
the second cutting path 490. Together the first and second mowers cutting in
conjunction
will create a diamond pattetn in the mowed fairway.
Referring again to Fig. 6, once the process is completed, a field map of the
area to be cut
with the cutting paths overlaid on the field map will have been created and
the method
will finish 450.
In one embodiment of the invention, the software process 400 is run on the
control
system 300, as shown in Fig. 5. The steps of the process 400 and stored field
maps are
saved in memory 330 and are implemented by the processing unit 310. A user
will make
selections for the field map, number of mowers, cutting patterrt, etc. on a
display device
and interface device (not shown). This embodiment might be particularly useful
for such
CA 02588269 2007-05-09
fields as baseball fields or a golf course, where the field maps will not
change from time
to time or there is a finite number of field maps to choose from, such as an
18 hole golf
course and the cutting pattems applied to the ficlds are relatively simple and
can be
drawn over the existing field maps quite easily.
In an altemative embodiment, the process 400 is implemented on a conventional
computer system 500, schematically illustrated in Fig. 10. Conventional
computer
systcm 500 is suitable for supporting the operation of the process 400 of the
present
invention. The conventional computer system 500 typically comprises: a
processing unit
l0 503; a memory storage device 504; an input device 505; a display device
507; and a
program module 508.
The processing unit 503 can be any processing unit that is typically known in
the art with
the capacity to run the program and is operatively connected to the memory
storage
device 504 such as a local hard-disk, etc. The input device 505 can be any
suitable
device suitable for inputting data into the computer system 501, such as a
keyboard,
mouse or data port such as a network connection and is coupled to the
processing unit
503 and operative to allow the proccssing unit 503 to receive inforrnation
from the input
device 505. The display device 507 can be any suitable device coupled to the
processing
unit 503 and operative for displaying data. The program module 508 is stored
in the
memory storage device 504 and operative to provide instructions to processing
unit 503
to implement the process 400 and the processing unit 503 responsive to the
instructions
of the program module 508.
CA 02588269 2007-05-09
Although other intemal components of a computer system 501 are not
illustrated, those of
ordinary skill in the art will appreciate that many more components and
interconnections
between them are well known and can be used. As well the computer system 501
need
not be limited to only one computer system and may comprise a network of
connected
computer systems.
By using conventional computer systcm 500, a user would have more flexibility
to
generate more complex cutting pattetns and apply them to more custonvzed
fields, in
order to generate a cutting path. Once the cutting path has been generated and
stored, it
can be saved onto some transportable media and the saved cutting path can be
used in
control system 300 to have a mower follow the control path.
Directing a Mower to Mow a Pattern into the Turf of a Field
Fig. 11 is a flow chart of a cutting path process 600 for mowing a field in a
specified
cutting pattern. The process 600 comprises: starting 602; loading a cutting
path 605;
guiding the mower to a starting point 608; and repeatedly; determining the
position of the
cutter 610; comparing the position of the mower to the cutting path 620; and
transmitting
correction control signals to steer the mower if it deviating from the cutting
path 640.
The cutting process 600 will start 602 and a cutting path will be loaded 605
into the
memory 330 of the control system 300. The cutting path will be a cutting path
that has
been created using the proccss 400, illustrated in Fig. 6.
CA 02588269 2007-05-09
Once the cutting path has been loaded 605, a starting point for the control
path will be
determined and the user will be guided to a starting point 608. The starting
point will
correspond to a start of a cutting path on the field map.
The operator of the mower will then start the mower moving. As the mower is
moving,
the control system 300 will guide the mower along the cutting path, by
repeatedly
determining a position 610, comparing the position to the cutting path 620;
and
transmitting correction control signals to steer the mower if it is deviating
from its cutting
path 640.
For each of these repetitions, the position of the mower is determined 610.
Referring to
Fig. 5, the syst.em will repeatedly determine the posilion of the cutter 610.
The
processing unit 310 of the control system 300 collects position coordinates
for the
position of the control system 300 from the GPS receiver 320.
Referting again to Fig. 11, next, the coordinates of the mower will be
compared to the
cutting path. Referring to Fig. 5, the processing unit 3l0 of the control
system 300
compares the coordinates from the GPS receiver 320 to the cutting path stored
in the
memory 330.
Referring again to Fig. 11, whether or not the mower is on the cutting path
will be
determined and if the mower is following the cutting path, the method will
check to see
CA 02588269 2007-05-09
whether the cutting path is completed 635 and the process will once again
dctermine the
position of the mower and follow steps 620. 630, etc, if the cutting path has
not been
completed.
Alternatively, if at 630, it is determined that the mower is no longer on the
cutting path,
correction signals are transmitted 640 to steer the mower back to the cutting
path.
Referring to Fig. 5, when the control system 300 determines that the mower is
deviating
from the cutting path, the processing unit 310 determines which way the
vehicle hat to be
steered, based on the position of the mower in relation to the desired cutting
path, and the
processing unit 310 will send a control signal through the input/output
interface 340.
In the first embodiment of the invention, the mower, being used to mow the
field, is
equipped with the automatic steering system 100, illustrated in Fig. 3, and
the control
signal transmitted by the control system 300 to the steering system 100 will
be
transmitted to the control circuit 110 to automatically steer the mower in
absence of any
input from the operator using the operators controls 70. The control system
300 will
determine whether the mower is deviating from the cutting path in either a
right or left
direction and provide a corresponding control signal to the control circuit
110 to steer the
mower back to the cutting path. Based on the control signal, the control
circuit 110 will
open a flow path for either the right diverting conduit 102 or left diverting
conduit 102,
causing the mower to turn in the opposite direction back towards the cutting
path.
CA 02588269 2007-05-09
In the second embodiment of the invention, the control signal transmitted
through the
input/output interface 340 of the control system 300 will be transmitted to a
user display
700 as illustrated in Fig. 12 and used to light either a left indicator light
710 or a right
indicator light 720. If the control system 300 determines that mower is
deviating from
the cutting path by drifting to the right of the cutting path, the control
signal will activate
a left indicator light 710 on the user display 700 to indicate to a user to
manually turn the
mower to the left to return to the cutting path. If the control system 300
determines that
the mower is deviating to the left of the cutting path, the control signal
will activate a
right indicator light 720 on the user display to indicate to a uscr to
manually turn the
lo mower to the right to return to the cutting path.
Referring again to Fig. 11, as the mower is moving back to the cutting path,
the process
600 will continue to determine the position of the mower 610, compare the
coordinates to
the cutting path 620 and until the mower is back on the cutting path, the
control signal
i will continue to be transmitted 640. Once the mower has moved back to the
cutting path,
when the position of the mower is determined 6l0 and the positioned compared
to the
cutting path 620, the mower will be determined to be on the path 630 and the
control
signal will stop being transmitted.
2o As the mower progresses along the cutting path, steps 610, 620, 630, 635
(and when
required step 640) will continually be repeated until the mowcr has completed
the cutting
path, at which time the field will be cut and cutting process 600 will end
650.
CA 02588269 2007-05-09
Although a system of the present invention can easily be incorporated as
original
equipment, so that a mower could be manufactured with the control system 300
and,
optionally, the steering system 50, outlined herein. Alternatively, the
control system
could be provided as an aftermarket kit to be added to an existing mower.
The foregoing is considered as illustrativc only of the principles of the
invention.
Further, since numerous changes and modifications will readily occur to those
skilled in
the art, it is not desired to limit the invention to the exact construction
and operation
shown and described, and accordingly, all such suitable changes or
modifications in
io structure or operation which may be resorted to are intended to fall within
the scope of
the claimed invention.
