CA3013859A1 - Controlling a positioning system for an agricultural implement - Google Patents

Abstract

A method and apparatus for controlling positioning of an agricultural implement is disclosed. The agricultural implement is mounted on a propulsion unit having a positioning system for positioning the agricultural implement. The apparatus includes a controller operably configured to receive a position signal from at least one position sensor, the position signal representing a position of the agricultural implement relative to the ground, the position sensor and the controller each being disposed on the agricultural implement. While a difference between the position of the agricultural implement and a desired position of the agricultural implement is greater than a threshold difference, the controller is further operably configured to produce and transmit an output signal to the positioning system of the propulsion unit, the output signal having a control state that alternates successively between an active time during which the output signal causes the positioning system to move the agricultural implement towards the desired position, and an inactive time during which the output signal causes the positioning system to discontinue movement of the agricultural implement. The active time and inactive time are selected based on a positioning response time of the positioning system and are operable to permit the agricultural implement to settle in a non-transient position during the inactive time while receiving the position signal from the at least one position sensor representing an updated current position of the agricultural implement.

Description

CONTROLLING A POSITIONING SYSTEM FOR AN AGRICULTURAL IMPLEMENT
BACKGROUND
1. Field This invention relates to positioning systems for agricultural implements and more particularly to conditioning or producing control signals for controlling a positioning system for an agricultural implement and/or producing position signals representing positioning of the agricultural implement.

2. Description of Related Art An agricultural implement such as a harvesting header on a combine/power-unit or a spray boom on a power unit may be driven across a field. During use, it may be desirable to control a position of the agricultural implement relative to the power unit or propulsion unit and thereby control a position of the implement relative to the ground or to crops on the field. Accurate control of the position of the agricultural implement may result in higher crop yields for harvesting and improved efficiency in spraying, for example.
Some agricultural control systems may sense a height or separation distance of the implement above the ground and produce control signals for causing a positioning system to move the implement relative to the propulsion unit, based on the sensed height.
However, when a positioning system receives a control signal and is directed to move the implement, there may be a response time before the positioning system is able to cause the implement to reach a fixed or generally non-transient position. Some agricultural control systems may not take into account the response time when producing the control signals for controlling the implement position.
Further, agricultural control systems may sense the position of the implement periodically.
Some control systems do not sense positioning frequently enough such that the control signals they produce can maintain accurate control of the implement. Accordingly, some agricultural control systems are constantly causing the agricultural implement to overshoot a desired setpoint position which may result in constant "hunting".

Further, some sensing systems may not be configured to sense changes in the ground at an intermediate position on the agricultural implement.
SUMMARY
In accordance with another disclosed aspect there is provided an apparatus for controlling positioning of an agricultural implement, the agricultural implement being mounted on a propulsion unit having a positioning system for positioning the agricultural implement. The apparatus includes a controller operably configured to receive a position signal from at least one position sensor, the position signal representing a position of the agricultural implement relative to the ground, the position sensor and the controller each being disposed on the agricultural implement. While a difference between the position of the agricultural implement and a desired position of the agricultural implement is greater than a threshold difference, the controller is further operably configured to produce and transmit an output signal to the positioning system of the propulsion unit, the output signal having a control state that alternates successively between an active time during which the output signal causes the positioning system to move the agricultural implement towards the desired position, and an inactive time during which the output signal causes the positioning system to discontinue movement of the agricultural implement.
The active time and inactive time are selected based on a positioning response time of the positioning system and are operable to permit the agricultural implement to settle in a non-transient position during the inactive time while receiving the position signal from the at least one position sensor representing an updated current position of the agricultural implement.
The controller may be operably configured to produce and transmit an output signal to the positioning system by transmitting an output signal over a vehicle communications bus implemented on the propulsion unit.
The apparatus may include a display disposed on the propulsion unit and in communication with the vehicle communications bus for displaying operating information associated with the controller on the agricultural implement, and the display may be operably configured to receive the output signal from the controller and to produce command signals for controlling the positioning system.

-3-The propulsion unit may include a controller operable to control functions of the propulsion unit and the controller on the propulsion unit may be operably configured to receive the output signals from the controller on the header for updating operating information associated with the agricultural implement.
The controller on the propulsion unit may be operably configured to receive operator input associated with controlling positioning of the agricultural implement and to transmit the operator input to the controller on the agricultural implement.
In accordance with one disclosed aspect there is provided a method for controlling positioning of an agricultural implement, the agricultural implement being mounted on a propulsion unit having a positioning system for positioning the agricultural implement. The method involves receiving a position signal from at least one position sensor at a controller, the position signal representing a position of the agricultural implement relative to the ground, the position sensor and the controller each being disposed on the agricultural implement. The method also involves, while a difference between the position of the agricultural implement and a desired position of the agricultural implement is greater than a threshold difference, causing the controller to produce and transmit an output signal to the positioning system of the propulsion unit, the output signal having a control state that alternates successively between an active time during which the output signal causes the positioning system to move the agricultural implement towards the desired position, and an inactive time during which the output signal causes the positioning system to discontinue movement of the agricultural implement. The active time and inactive time are selected based on a positioning response time of the positioning system and are operable to permit the agricultural implement to settle in a non-transient position during the inactive time while receiving the position signal from the at least one position sensor representing an updated current position of the agricultural implement.
Causing the controller to produce and transmit an output signal to the positioning system may involve causing the controller to transmit an output signal over a vehicle communications bus implemented on the propulsion unit.
Operating information associated with the controller on the agricultural implement may be

-4-displayed on a display disposed on the propulsion unit and in communication with the vehicle communications bus, and may further involve causing the display to receive the output signal from the controller and to produce command signals for controlling the positioning system.
The propulsion unit may include a controller operable to control functions of the propulsion unit and the method may further involve causing the controller on the propulsion unit to receive the output signals from the controller on the header for updating operating information.
The method may involve receiving operator input at the controller on the propulsion unit associated with controlling positioning of the agricultural implement and transmitting the operator input to the controller on the agricultural implement.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate embodiments of the invention, Figure 1 is a perspective view of an agricultural apparatus including a system for controlling movement of an agricultural implement according to one embodiment of the invention;
Figure 2 is a schematic view of the system of Figure 1 according to one embodiment;
Figure 3 is a schematic view of the system of Figure 1 according to one embodiment;
Figure 4 is a side view of the apparatus of Figure 1;
Figure 5 is a schematic view of a processor circuit for implementing a conditioner included in the system of Figure 1;
Figure 6A is a representation of an exemplary portion of a lift control signal;
Figure 6B is a representation of an exemplary portion of a drop control signal;

-5-Figure 7 is a flowchart depicting blocks of code for directing the conditioner shown in Figure to facilitate signal conditioning;
5 Figure 8 is a flowchart depicting sub-blocks of code included in the blocks of code shown in Figure 7;
Figure 9 is a representation of an exemplary controller signal record used by the processor circuit of Figure 5;
Figure 10 is a flowchart depicting sub-blocks of code included in the blocks of code shown in Figure 7 Figure 11A is a representation of an exemplary portion of a conditioned lift control signal;
Figure 11B is a representation of an exemplary portion of a conditioned drop control signal;
Figure 12 is a representation of an exemplary signal time record used by the processor circuit of Figure 5;
Figure 13 is a schematic view of portion of the system of Figure 1 according to one embodiment;
Figure 14 is a flowchart depicting blocks of code for directing the conditioner shown in Figure 5 to facilitate time length determining;
Figure 15 is a representation of an exemplary system information record used by the processor circuit of Figure 5;
Figure 16 is a flowchart depicting sub-blocks of code included in the blocks of code shown in Figure 14;

-6-Figure 17 is a representation of an exemplary controller time length record used by the processor circuit of Figure 5;
Figure 18 is a flowchart depicting blocks of code for directing the conditioner shown in Figure 5 to facilitate continuous control override;
Figure 19 is a flowchart depicting sub-blocks of code included in the blocks of code shown in Figure 18;
Figure 20 is a representation of an exemplary threshold time record used by the processor circuit of Figure 5;
Figure 21 is a schematic view of a system for controlling movement of an agricultural implement according to one embodiment of the invention;
Figure 22 is a schematic view of a processor circuit for implementing a controller/conditioner included in the system of Figure 21;
Figure 23 is a flowchart depicting blocks of code for directing the controller/conditioner shown in Figure 22 to facilitate signal producing;
Figure 24 is a representation of an exemplary sensed height record used by the processor circuit of Figure 22;
Figure 25 is a representation of an exemplary desired height record used by the processor circuit of Figure 22;
Figure 26 is a schematic view of a system for controlling movement of an agricultural implement according to one embodiment of the invention;
Figure 27 is a perspective view of an agricultural apparatus including the system of Figure 26;

-7-Figure 28 is a schematic view of a processor circuit for implementing a modifier included in the system of Figure 26;
Figure 29 is a flowchart depicting blocks of code for directing the modifier shown in Figure 28 to facilitate position signal modifying;
Figure 30 is a representation of an exemplary position record used by the processor circuit of Figure 28;
Figure 31 is a representation of an exemplary representative position record used by the processor circuit of Figure 28;
Figure 32 is a representation of an exemplary representative position record used by the processor circuit of Figure 28;
Figure 33 is a perspective view of an agricultural apparatus in accordance with another disclosed embodiment;
Figure 34 is a block diagram of a control system for controlling the agricultural apparatus shown in Figure 33;
Figure 35 is a schematic view of a processor circuit for implementing a header controller shown in Figure 33 and Figure 34; and Figure 36 is a flowchart depicting blocks of code for directing the processor circuit shown in Figure 35 to control positioning of an agricultural implement associated with the agricultural apparatus shown in Figure 33.
DETAILED DESCRIPTION
Referring to Figure 1, an agricultural apparatus in accordance with one embodiment is shown at 30. In the embodiment shown, the agricultural apparatus 30 is an agricultural combine harvester including a header 12, which acts as an agricultural implement, mounted to a

-8-propulsion and processing unit 14 (hereinafter referred to as a "propulsion unit"), which acts as a frame.
In various embodiments, the header 12 is configured to harvest crop material from crops growing in a field while the apparatus 30 is driven across the field by the propulsion unit 14.
The header 12 is configured to collect the crop material and transfer the crop material to the propulsion unit 14 which may be configured to process the crop material.
In various embodiments, the header 12 may be able to efficiently harvest the crop material when the header 12 is kept at a constant height or separation distance close to the ground, without striking the ground. As the apparatus 30 travels over the ground, the ground may have inconsistencies and undulations and therefore in order to keep the header 12 at a constant height relative to the ground, in various embodiments, the apparatus has a sensor system 16 to sense changes in the ground, which may act as a reference surface. The apparatus 30 then controls a position of the header 12 relative to the propulsion unit 14 to maintain the header at a constant or desired height above the reference surface.
Referring to Figure 2, to control the position of the header 12, the apparatus 30 shown in Figure 1 includes a system 10 for controlling movement of the agricultural implement relative to the frame. The system 10 includes a controller system 11 including the sensor system 16, a controller 18, and a positioning system 22. The controller system 11 may be a known controller system such as supplied by a manufacturer of the apparatus for controlling movement of the agricultural implement.
Referring to Figure 2, the sensor system 16 is configured to sense a position of the agricultural implement and to transmit position signals representing the sensed position to the controller 18. The controller 18 receives the position signals representing the sensed position and compares the sensed position to a desired position to determine a difference.
The controller 18 then produces control signals, based on the difference. The controller 18 is configured to transmit the control signals to the positioning system 22 which may control hydraulic actuators, for example to cause movement of the agricultural implement towards a desired position relative to the frame. While the embodiments herein are described with reference to hydraulic

-9-actuators, in some embodiments other types of actuators such as electrical actuators may be employed to cause movement of the agricultural implement.
The positioning system 22 has a positioning response time for causing the agricultural implement to respond to the control signals. In cases where the positioning system has a positioning response time that results in excessive movement or "hunting" for the desired position, according to the teachings herein the system 10 is provided with a signal conditioner 20, which is configured to condition the control signals transmitted by the controller 18 and normally received by the positioning system 22. The conditioner 20 is configured to intercept the control signals transmitted by the controller 18 and to transmit conditioned control signals or output signals to the positioning system 22 instead of the control signals, in response to the control signals transmitted by the controller 18.
The conditioned control signals may represent a plurality of active times during which the positioning system 22 is instructed to move the agricultural implement towards a desired position and a plurality of inactive times during which the positioning system 22 is instructed not to move, with each active time being followed by a respective one of the inactive times. In some embodiments the conditioner 20 may be configured to cause the inactive times to be sufficiently long to permit the agricultural implement to settle into a fixed position due to the positioning response time of the positioning system 22. In some embodiments, the agricultural implement may be considered to be in a fixed position when the agricultural implement is generally non-transient or when the agricultural implement would not substantially change its general position, given further time.
In some embodiments, an oscillating agricultural implement may be considered to have settled into a fixed position.
Referring back to Figure 1, the system 10 of Figure 2 is mounted on the apparatus 30. In the embodiment shown, the sensor system 16 includes left, and right sensors 32 and 36 located at first and second locations on left and right ends respectively of the header 12.
Referring to Figures 1 and 3, the sensors 32 and 36 are configured to send left and right position signals 40 and 44 representing left and right sensed positions or heights of respective locations on the header 12 relative to the ground to the controller 18. In some embodiments, the sensors

-10-32 and 36 may each include a sensing arm or paddle (shown at 33 and 37 in Figure 1) and a Hall Effect sensor configured to sense a rotational angle of the sensing arm.
In various embodiments the left and right position signals 40 and 44 may be electrical signals which have a voltage level representing a sensed position or height measured by their respective sensor. For example, the voltage level of the left and right position signals 40 and 44 may be between a low voltage level and a high voltage level, with a low voltage level representing 0% of a maximum sensed height and high voltage level representing 100% of the maximum sensed height. For example, in some embodiments, the low voltage level may be about 1 Volt and the high voltage level may be about 4 Volts. However, in various other embodiments, the high and low voltage levels of the left and right position signals 40 and 44 may be other voltage levels.
In the embodiment shown, the sensors 32 and 36 have a minimum sensed height of about 0 inches and a maximum sensed height of about 18 inches. However, in various embodiments, the sensors 32 and 36 may sense other ranges of heights.
In various embodiments, the sensors 32 and 36 may transmit the left and right position signals 40 and 44 to the controller 18 using electrical wires, for example, coupled to a respective one of the sensors 32 and 36 at one end and to the controller 18 at another end.
Referring still to Figure 3, in various embodiments, the controller 18 may be configured to receive or sample the left and right position signals 40 and 44 representing the left and right sensed heights of the header 12. In some embodiments, the controller 18 may be configured to sample the position signals periodically, such as once every about 320 ms, for example. The controller 18 is configured to compare each of the left and right sensed heights with desired left and right heights respectively to determine differences between the sensed heights and the desired heights. In some embodiments, the controller 18 may be configured to receive signals representing the desired left and right heights from memory and/or via an I/O
interface of the controller 18, for example. The desired heights may be about 2", for example.

-11-The controller 18 may, based on the differences between the sensed heights and the desired heights, produce lift and drop control signals 46 and 48 for causing the positioning system 22 to move the header 12 towards the desired heights.
For example, in some embodiments, the controller 18 may be configured to determine a left difference between the left sensed height and the left desired height and to determine a right difference between the right sensed height and the right desired height. When at least one of the left and right differences represents a sensed height that is less than a desired height and has an absolute value that is greater than a threshold difference, the controller 18 may produce the lift and drop control signals 46 and 48 such that, if the control signals were transmitted to the positioning system 22, the control signals would cause the positioning system 22 to cause the header 12 to be raised relative to the propulsion unit 14 shown in Figure 1. If neither of the left and right differences represents a sensed height that is less than a desired height and has an absolute value that is greater than the threshold difference and at least one of the left and right differences represents a sensed height that is greater than a desired height and has an absolute value that is greater than a threshold difference, the controller 18 may produce the lift and drop control signals 46 and 48 such that, if the control signals were transmitted to the positioning system 22, the control signals would cause the positioning system 22 to drop (i.e. lower) the header 12 relative to the propulsion unit 14 shown in Figure 1. If the left and right differences are both within a threshold range, the controller 18 may produce the lift and drop control signals 46 and 48 to cause the positioning system 22 to not change the height of the header 12 relative to the propulsion unit 14 shown in Figure 1.
As discussed above, the controller 18 may be configurable to transmit the lift and drop control signals 46 and 48 directly to the positioning system 22 but, in the embodiment shown in Figure 3, the conditioner 20 is configured to intercept the lift and drop control signals 46 and 48.
Referring to Figure 3, the conditioner 20 is configured to intercept the lift and drop control signals 46 and 48 produced by the controller 18 and to produce and transmit conditioned lift and drop control or output signals 50 and 52 to the positioning system 22 instead of the control signals. The conditioned lift and drop output signals 50 and 52 represent a plurality of active times during which the positioning system 22 is instructed to move the header

12 shown in Figure 1 towards the desired position and a plurality of inactive times during which the positioning system 22 is instructed not to move, with each active time being followed by a respective one of the plurality of inactive times. In various embodiments the conditioner 20 may be configured to cause the inactive times to be sufficiently long to permit the header 12 shown in Figure 1 to settle into a fixed position due to a positioning response time of the positioning system 22.
In various embodiments, by causing each active time to be followed by a respective inactive time wherein the positioning system is allowed to settle into a fixed position, the conditioner 20 may allow the controller 18 to sample the left and right position signals 40 and 44 and thus sense heights during a time when the header 12 is generally non-transient or has reached a fixed position. In various embodiments, this non-transient height sensing may facilitate more accurate height sensing and thus better control of the position of the header 12 than would be provided by simply transmitting the lift and drop control signals directly from the controller to the positioning system.
Referring to Figure 3, the positioning system 22 is configured to receive the conditioned lift and drop output signals 50 and 52 from the conditioner 20 and to cause hydraulic actuators to move the header 12 shown in Figure 1 in accordance with the conditioned output signals.
Figure 4 shows a side view of the apparatus 30 without the header 12 attached, showing elements of the positioning system 22, in accordance with one embodiment.
Referring to Figure 4, the positioning system 22 includes a feeder house 60 pivotally connected to the propulsion unit 14 at pivot point 62. The positioning system 22 also includes a height controlling hydraulic system including a height-controlling hydraulic cylinder 64 connected at one end to the feeder house 60 and at the other end to the propulsion unit 14. The height controlling hydraulic system may include a "lift" valve, such as, for example, a solenoid controlled valve which may be controlled using the conditioned lift output signal 50 and a "drop" valve, such as, for example, a solenoid controlled valve, which may be controlled using the conditioned drop output signal 52.
When the lift valve is opened and the drop valve is closed, the height-controlling hydraulic cylinder 64 extends. Conversely, when the lift valve is closed and the drop valve is opened, the height-controlling hydraulic cylinder 64 retracts.

-13-The header 12 shown in Figure 1 is mounted to a front portion 66 of the feeder house 60 shown in Figure 4. Extension of the height-controlling hydraulic cylinder 64 causes the front portion 66 (and thus the header 12 shown in Figure 1 when attached to the front portion 66) to move upward relative to the propulsion unit 14 in the direction of arrow 67.
Conversely, retraction of the height-controlling hydraulic cylinder 64 may cause the front portion 66 (and thus the header 12 shown in Figure 1 when attached to the front portion 66) to move downward relative to the propulsion unit 14 in the direction of arrow 69.
As discussed above, in various embodiments, each time the positioning system 22 is instructed to move, there may be a positioning response time before the positioning system 22 finishes moving and reaches a generally non-transient or fixed position. in various embodiments, the positioning response time may be due to a variety of factors such as, for example, weight and momentum of the feeder house 60 and/or the header 12, time required for valves of the height-controlling hydraulic cylinder 64 to open and/or close after being commanded to do so, and/or float in the height-controlling hydraulic cylinder.
Referring back to Figure 3, in various embodiments, the system 10 may optionally include system sensors 47 for sensing system information and transmitting system information signals 49 representing the system information to the conditioner 20. In some embodiments, the conditioner 20 may be configured to adjust properties of the lift and drop output signals 50 and 52 based on the system information. For example, as will be described in further detail below, in various embodiments, the conditioner 20 may be configured to determine active and inactive time lengths for the lift and drop output signals 50 and 52 based on the system information.
Processor Circuit - Conditioner Referring to Figure 5, a processor circuit for implementing the conditioner 20 shown in Figure 1 according to one embodiment is shown generally at 200. The processor circuit 200 includes a conditioner processor 202, a program memory 204, a variable memory 206, and an input output ("I/O") interface 212, all of which are in communication with the conditioner processor 202. For example, the conditioner processor 202 may be an ARM' CortexT"-M3 processor.

-14-Program codes for directing the conditioner processor 202 to carry out various functions are stored in the program memory 204. The program memory 204 may be implemented as any form of computer-readable memory or storage medium, such as, for example, read only memory (ROM), random access memory (RAM), a hard disk drive (HDD), solid state memory, a network drive, flash memory, removable memory, and/or a combination thereof, for example.
In various embodiments, the variable memory 206 may be implemented in RAM, a hard drive, solid state memory, a network drive, flash memory, a memory stick or card, removable memory, any other form of computer-readable memory or storage medium and/or any combination thereof.
In various embodiments, the program memory 204 includes a block of codes 220 for directing the conditioner processor 202 to perform signal conditioning functions a block of codes 222 for directing the conditioner processor 202 to perform time length determining functions, and a block of codes 224 for directing the conditioner processor 202 to perform continuous control functions. The program memory 204 also includes at least one memory location 236 for storing controller time information and at least one memory location 238 for storing threshold time information.
The variable memory 206 may include a plurality of storage locations including locations 230 for storing controller signal information, locations 232 for storing time length information, and locations 234 for storing system information.
The I/O interface 212 includes input ports 250 and 252 for receiving control signals such as, for example, the lift and drop control signals 46 and 48, and output ports 260 and 262 for producing and transmitting the conditioned output signals 50 and 52 to the positioning system. In the embodiment shown, the I/O interface also includes input ports 254, 256, 258, 259, 263, 264, 266, 268, 270, 272, and 274 for receiving user input signals, pressure signals, travel speed signals, engine speed signals, temperature signals, fuel consumption signals, acceleration signals, payload fill level signals, implement identifier signals, controller identifier signals, and user control signals, respectively. In various embodiments, the I/O interface 212 may include an analog to digital converter in communication with the input ports and a digital to analog converter in communication with the output ports, for example.

-15-Each of the input ports and output ports shown in Figure 5 are shown as single ports which are distinct and separate. However, in various embodiments, one or more of the input and output ports may be implemented using one or more ports.
Referring to Figures 6A and 6B exemplary representations of the lift and drop control signals 46 and 48 during a time period, in accordance with one embodiment, are shown. The lift control signal 46 affects control of the lift valve of the height hydraulic system and the drop control signal 48 affects control of the drop valve of the height hydraulic system.
In various embodiments, a high voltage level of VH on the lift control signal 46 shown in Figure 6A, if communicated to the lift valve of the height hydraulic system shown in Figure 4 may cause the lift valve to open and a low voltage level of VL, if communicated to the lift valve of the height hydraulic system may cause the lift valve to close. Similarly, a low voltage level of VL on the drop control signal 48 shown in Figure 6B, if communicated to the drop valve of the height hydraulic system may cause the drop valve to close and a high voltage level of VH if communicated to the drop valve of the height hydraulic system may cause the drop valve to open.
The voltage levels VH and VL may vary depending on a type of the controller 18 shown in Figure 3.
For example, in some embodiments, for some controllers, the high voltage level of VH may be about 12 volts and the low voltage level VL may be about 0 volts.
In various embodiments, the lift and drop control signals 46 and 48, which are represented in accordance with one embodiment in Figures 6A and 6B, and shown in context in Figure 3, may fall within one of three control states at a given time. In an up control state, the lift control signal 46 has a high voltage level of VH and the drop control signal 48 has a low voltage level of VL. When the lift and drop control signals 46 and 48 are in the up control state, the lift and drop control signals 46 and 48, if communicated to the positioning system 22, cause the lift valve to open and the drop valve to close such that the height-controlling hydraulic cylinder 64 shown in Figure 4 extends and thus raises the header 12 shown in Figure 1.
In a down control state, the lift control signal 46 has a low voltage level of VL and the drop control signal 48 has a high voltage level of VH. When the lift and drop control signals 46 and 48

-16-are in the down control state, the lift and drop control signals 46 and 48, if communicated to the positioning system 22, cause the lift valve to close and the drop valve to open such that the hydraulic cylinder 64 shown in Figure 4 retracts and thus lowers the header 12 shown in Figure 1.
In an off control state both of the lift and drop control signals 46 and 48 have a low voltage level of VL. Accordingly, when the lift and drop control signals 46 and 48 are in the off control state, the lift and drop control signals 46 and 48, if communicated to the positioning system 22, cause both the lift valve and the drop valve to close such that the hydraulic cylinder 64 shown in Figure 4 does not move and the positioning system 22 holds the header 12 shown in Figure 1 at a constant height relative to the propulsion unit.
Signal Conditioning Referring to Figure 5, the signal conditioning block of codes 220 of the processor circuit 200 are shown in greater detail in Figure 7, and include a first block 302 which directs the conditioner processor 202 shown in Figure 5 to intercept control signals by causing the I/O interface 212 to receive the lift and drop control signals 46 and 48 via the input ports 250 and 252 shown in Figure 5. Block 302 is shown in greater detail in Figure 8 wherein it is seen that block 302 includes block 322 which directs the conditioner processor 202 to sample the lift and drop control signals 46 and 48 at the input ports 250 and 252 of the I/O interface 212 shown in Figure S. For example, block 322 of Figure 8 may be executed at time t1 shown in Figures 6A and 6B
and block 322 may direct the conditioner processor 202 to cause the I/O
interface 212 shown in Figure 5 to sample the lift and drop control signals 46 and 48 at time ti such that the sampled voltage levels of the lift and drop control signals 46 and 48 are VH and VL
respectively.
Referring back to Figure 8, block 324 then directs the conditioner processor 202 shown in Figure 5 to store controller signal information representing the lift and drop control signals 46 and 48 in memory. In one embodiment, block 324 may direct the conditioner processor 202 to store the controller signal information in a controller signal record representing the lift and drop control signals 46 and 48 in locations 230 of the variable memory 206 shown in Figure 5.

-17-A representation of an exemplary controller signal record is shown at 340 in Figure 9. The controller signal record 340 includes a lift valve field 342 and a drop valve field 344 for storing respective Boolean representations of the lift and drop control signals 46 and 48 which were sampled at input ports 250 and 252 respectively of the I/O interface 212 shown in Figure 5 at time t1. The controller signal record 340 shown in Figure 9 also includes a time field 346 for storing a representation of the time at which the lift and drop control signals 46 and 48 were sampled.
In various embodiments, the time field 346 shown in Figure 9 may store a representation of time that may be established by a real time clock or be relative based on a microprocessor clock rate and a cycle count. In various embodiments, the units of measure for the representation of time may be accurate to between microseconds and milliseconds. In the embodiment shown in Figure 9, the time field 346 stores a value having a format of YYYYMMDDHHMiMiSSTTT, where YYYY represents the year, MM represents the month, DD represents the day of the month, HH
represents the hour, MiMi represents the minute, SS represents the second, and TTT represents the thousandths of a second. In some embodiments, the time field 346 may store other representations of time which may, for example, include less information than is shown in Figure 9. For example, in various embodiments, the time field 346 may not include representations of the year, month, day, hour, or minute.
In various embodiments, block 324 of Figure 8 may direct the conditioner processor 202 shown in Figure 5 to store a value of TRUE in the lift valve field 342 of Figure 9 when the lift control signal 46 received at the input port 250 shown in Figure 5 represents a voltage of VH and to store a value of FALSE in the lift valve field 342 when the lift control signal represents a voltage of VL.
Similarly, block 324 may direct the conditioner processor 202 to store a value of TRUE in the drop valve field 344 when the drop control signal 48 received at the input port 252 represents a voltage of VH and to store a value of FALSE in the drop valve field 344 when the drop control signal represents a voltage of VL.
For example when block 322 of Figure 8 is executed at time t1 shown in Figure 6A, the lift control signal 46 sampled at the input port 250 shown in Figure 5 has a voltage of VH and the drop control signal 48 received at the input port 252 has a voltage of VL.
Accordingly, block 324

-18-may direct the conditioner processor 202 to store a value of TRUE in the lift valve field 342 and a value of FALSE in the drop valve field 344, as shown in Figure 9. In various embodiments, block 324 may direct the conditioner processor 202 to store the controller signal record 340 shown in Figure 9 in locations 230 of the variable memory 206 shown in Figure 5.
Referring back to Figure 7, after block 302 has been executed, block 304, directs the conditioner processor 202 shown in Figure 5 to cause the I/O interface 212 shown in Figure 5 to produce and transmit at least one conditioned output signal, in this embodiment two conditioned output signals (such as shown in Figures 11A and 11B), to the positioning system 22 shown in Figure 3 instead of the lift and drop control signals, wherein the conditioned output signals represent an active time (e.g. 368) during which the positioning system 22 is instructed to move the header 12 shown in Figure 1 towards a desired position and an inactive time (e.g.
370) following the active time during which the positioning system 22 is instructed not to move, wherein the inactive time (e.g. 370) is sufficiently long to permit the header 12 to settle into a fixed position due to the positioning response time of the positioning system 22.
In various embodiments, the length of the active time (e.g. 368) and the inactive time (e.g. 370) enables the controller 18 to sample the left and right position signals 40 and 44 and update the control signals 46 and 48 when the header 12 has reached a fixed position.
Once block 304 is complete, the conditioner processor 202 is directed back to block 302. Figure 7 thus depicts an endless loop with timings based on known controller 18 and/or positioning system 22 performance, as described in further detail below.
Referring to Figure 10, block 304 includes blocks of code beginning with block 381 which directs the conditioner processor 202 to cause the I/O interface 212 shown in Figure 5 to set the lift and drop output signals 50 and 52 at the output ports 260 and 262 to a voltage of VL.
Block 382 of Figure 10 then directs the conditioner processor 202 shown in Figure 5 to retrieve controller signal information from locations 230 of the variable memory 206.
In the embodiment shown, block 382 directs the conditioner processor 202 to retrieve the most recently stored controller signal record 340 as shown in Figure 9, from locations 230 of the variable memory 206 shown in Figure 5.

-19-Block 384 of Figure 10 then directs the conditioner processor 202 shown in Figure 5 to determine whether the contents of the lift valve field 342 of the controller signal record 340 retrieved at block 382 are set to TRUE. If at block 384, the conditioner processor 202 determines that the contents of the lift valve field are set to TRUE, block 384 directs the conditioner processor 202 to block 386. If the conditioner processor 202 determines that the contents of the lift valve field are not set to TRUE, block 384 directs the conditioner processor 202 to block 390.
When block 386 of Figure 10 is executed, block 386 directs the conditioner processor 202 to cause the output port 260 of the I/O interface 212 shown in Figure 5 to produce a lift output signal having a voltage of VH for the active time 368 as shown in Figure 11A
and a voltage of VL
for the inactive time 370. A first lift signal portion 364 of the lift output signal 50 is thus transmitted to the positioning system 22 shown in Figure 3.
In the embodiment shown, a signal time record 420 as shown in Figure 12 is stored in locations 234 of the variable memory 206 shown in Figure 5. The signal time record 420 includes an active time length field 422 for storing a representation of an active time length and an inactive time length field 424 for storing a representation of an inactive time length.
In some embodiments, the signal time record 420 may be initialized by a manufacturer of the conditioner 20, for example. In some embodiments, as described in further detail below, the signal time record 420 may be derived from system information.
Referring back to Figure 10, block 386 directs the conditioner processor 202 to read the active time length field 422 of the signal time record 420 shown in Figure 12 and to cause the I/O
interface 212 shown in Figure 5 to cause the output port 260 to produce a low level voltage VH
for an active time having a length corresponding to the contents of the active time length field.
Block 386 similarly directs the conditioner processor 202 to read the inactive time length field 424 of the signal time record 420 and cause the I/O interface 212 to cause the output port 260 to produce a low level voltage VL for an inactive time having a length corresponding to the contents of the inactive time length field.

-20-Referring to Figure 11A, in the embodiment shown, block 386 has directed the conditioner processor 202 to cause the conditioned lift output signal to have the first lift signal portion 364 having the active time 368 having a voltage of VH and a length of 20 ms, corresponding to the value stored in the active time length field 422 of the signal time record 420 shown in Figure 12.
In some embodiments, the active time 368 has a length between 10 ms and 40 ms.
Block 386 has also directed the conditioner processor 202 to cause the first lift signal portion 364 to have the inactive time 370 having a voltage of VL and a length of 300 ms, corresponding to the value stored in the inactive time length field 424 of the signal time record 420 shown in Figure 12. In some embodiments, the inactive time 370 has a length between 180 ms and 310 ms.
The conditioned drop output signal 52 shown in Figure 11B remains unchanged during the active and inactive times 368 and 370 of the first lift signal portion 364 and thus the drop output signal 52 includes a first drop signal portion 366 having a voltage of VL, as was set at block 381 of Figure 10.
If at block 384 of Figure 10, the conditioner processor 202 shown in Figure 5 determines that the lift valve field is not set to TRUE, or, upon completion of block 386, the conditioner processor 202 is directed to block 390.
Block 390 directs the conditioner processor 202 shown in Figure 5 to determine whether a drop valve field of the controller signal record retrieved at block 382 is set to TRUE. If so, the conditioner processor 202 is directed to block 392. If at block 390, the conditioner processor 202 determines that the drop valve field is not set to TRUE, i.e. is set to FALSE, block 390 directs the conditioner processor 202 to end the process.
Block 392 of Figure 10 is generally similar to block 386, except that block 392 directs the conditioner processor 202 to cause the output port 262 of the I/O interface 212 shown in Figure 5 to produce the conditioned drop output signal.
When the positioning system 22 shown in Figure 3 receives the conditioned lift and drop output signals 50 and 52 shown in Figures 11A and 11B during the active time 368, the output signals are in an up control state and so the positioning system 22 is instructed to open the lift valve

-21-and close the drop valve of the height hydraulic system shown in Figure 4 and thus raise the header 12 shown in Figure 1.
Referring to Figure 11A, at time t2, the conditioner processor 202 causes the output 260 to cause the lift output signal 50 to transition from VH to VL and thus the positioning system 22 shown in Figure 4 is instructed to close the lift valve. Closing of the lift valve may not occur instantaneously after the conditioned lift output signal changes at time t2 due to its response time and even after the lift valve is closed, the header 12 shown in Figure 1 may continue to move, due to various factors, such as, for example, momentum and/or float in the height hydraulic system shown in Figure 4. Accordingly, the header 12 shown in Figure 1 may continue to move during a positioning response time 372 shown in Figure 11A at the beginning of the inactive time 370 until the header 12 settles into a fixed position.
The inactive time length field 424 should be set to represent a time length that is greater than the positioning response time 372, such that block 386 directs the conditioner processor 202 to cause the conditioned lift output signal 50 to have an inactive time having a sufficient length to include a stable time 373 during which the header 12 has settled into a fixed position. The length of the active time may be sufficiently short and the length of the inactive time may be sufficiently long and suitable delays can be provided by codes in blocks 302 or 304 to facilitate the controller 18 sampling the left and right position signals 40 and 44 and during the stable time 373.
For example, after block 304 of Figure 7 has been executed and the first lift and drop signal portions 364 and 366 as shown in Figures 11A and 1113 have been produced, the codes of block 304 may cause the conditioner processor 202 to execute at time t3, for example, block 302 which directs the conditioner processor 202 to sample the lift and drop signals and store a controller signal record having a lift valve field set to TRUE and a drop valve field set to FALSE in accordance with the lift and drop signals as seen at t3 in Figures 6A and 6B.
As shown in Figure 10 block 304 then directs the conditioner processor 202 to cause the outputs 260 and 262 of the I/O interface 212 to produce a second lift signal portion 400 and a second drop signal portion 402 shown in Figures 11A and 11B on the output ports 260 and 262

-22-respectively. Referring to Figure 11A, the second lift signal portion 400 includes an active time 375 and an inactive time 376.
Blocks 302 and 304 of Figure 7 are then executed again, this time at time t4 shown in Figures 6A, 6B, 11A and 11B. Blocks 302 and 304 direct the conditioner processor 202 to cause the outputs 260 and 262 of the I/O interface 212 to produce a third lift signal portion 404 as shown in Figure 11A and a third drop signal portion 406 as shown in Figure 11B. Referring to Figure 11A, the third lift signal portion 404 includes an active time 374 and an inactive time 378.
Blocks 302 and 304 of Figure 7 are then executed at time ts shown in Figures 6A, 6B, 11A and 11B and at this time (t5), the controller 18 shown in Figure 3 has determined that a representative sensed height is greater than a desired representative height and so the controller 18 has set the lift and drop control signals 46 and 48 into a drop control state by setting the lift and drop control signals 46 and 48 to VL and VH respectively, as shown in Figures 6A and 6B.
Therefore, when the conditioner processor 202 executes block 324 of Figure 8, at time t5, the conditioner processor 202 stores a controller signal record having a lift valve field set to FALSE
and a drop valve field set to TRUE.
Referring to Figure 10, block 384 directs the conditioner processor 202 to block 390, which directs the conditioner processor 202 to block 392. Block 392 directs the conditioner processor 202 to cause the output 262 of the I/O interface 212 to produce a fourth drop signal portion 410 having an active time 412 and inactive time 414 respectively, while the output port 260 transmits a fourth lift signal portion 408.
Referring to Figures 11A and 11B, during the active time 412, the output signals 50 and 52 are in a drop control state and the positioning system 22 is instructed to open the drop valve of the height hydraulic system to retract the cylinder, causing the header 12 shown in Figure 1 to be lowered. In various embodiments, the inactive time 414 may be greater than a positioning response time of the positioning system 22. The active time 412 and the inactive time 414 shown in Figures 11A and 11B should be set to sufficient lengths to facilitate the controller 18

-23-sampling the left and right position signals 40 and 44 shown in Figure 3 and updating the control signals 46 and 48 during a stable time.
In effect blocks 302 and 304 of Figure 7 are executed in a continuous loop such that the conditioner processor 202 shown in Figure 5 effectively intercepts the lift and drop control signals 46 and 48 produced by the controller 18 and produces the lift and drop output signals 50 and 52.
More particularly, blocks 302 and 304 of Figure 7, when executed a plurality of times during the time period shown in Figures 11A and 11B, direct the conditioner processor 202 to produce the lift and drop output signals 50 and 52 shown in Figures 11A and 11B
representing a plurality of active times including the active times 368, 375, 374, and 412 during which the positioning system 22 shown in Figure 4 is instructed to move and a plurality of inactive times including the inactive times 370, 376, 378, and 414 during which the positioning system 22 shown in Figure 4 is instructed not to move, each active time 368, 375, 374, and 412 being followed by a respective one of the plurality of inactive times 370, 376, 378, and 414, wherein each of the plurality of inactive times 370, 376, 378, and 414 is sufficiently long to permit the header 12 shown in Figure 1 to settle into a fixed position due to the positioning response time of the positioning system 22.
Blocks 302 and 304 thus direct the conditioner processor 202 to condition the lift and drop control signals 46 and 48 transmitted by the controller 18, normally received by the positioning system 22, and configured to cause movement of the header 12 relative to a frame towards a desired position, by producing the conditioned lift and drop signals.
Time Length Determining In various embodiments, the conditioner 20 shown in Figure 3 may be configured to improve performance of the system 10 by determining, based on system information, lengths for the active times and the inactive times to be represented by the output signals.
For example, in various embodiments, the conditioner 20 shown in Figures 1 ¨ 3 and 5 may be configured to receive system information from the system sensors 47 via the system information signals 49

-24-and to determine the lengths of the active times and/or inactive times based on the received system information.
Referring to Figure 13, in the embodiment shown, the system sensors 47 include a user input device 480 for receiving user input, a hydraulic pressure sensor 482, such as a hydraulic pressure sensor on a combine main pump output, for sensing pressure in a reservoir configured to control the height hydraulic cylinder 64 shown in Figure 4, a travel speed sensor 484, such as a GPS true ground speed sensor, for sensing a travel speed of the apparatus 30 shown in Figure 1, an engine speed sensor 486, such as an engine RPM sensor, for sensing an engine speed for an engine that provides power to the positioning system 22 shown in Figure 4, a hydraulic temperature sensor 498, such as a hydraulic temperature sensor at the reservoir configured to control the height hydraulic cylinder 64, for sensing a temperature of the hydraulic fluid contained in the reservoir, a fuel consumption sensor 488, such as an engine fuel flow meter, for sensing a rate at which the engine that provides power to the positioning system 22 is consuming fuel, an accelerometer 490, such as a vertical accelerometer on the header 12 shown in Figure 1, for sensing acceleration of the header 12, fill level sensors 492, such as a hopper fill level sensor on the propulsion unit 14 shown in Figure 1, for sensing a payload fill level of the propulsion unit 14, an implement identifier device 494 for identifying the header 12 shown in Figure 1, and a controller identifier device 496 for identifying the controller 18 shown in Figure 3.
Referring still to Figure 13, in various embodiments, the user input device 480 is configured to transmit a user input signal 481 representing received user input to the conditioner 20.
In some embodiments, a user may wish to modify system performance or speed with which the system 10 shown in Figure 3 responds to changes in the sensed environment. The user may use the user input device 480 shown in Figure 13 to produce the user input signal 481 representing a user-defined speed with which the user wishes the system 10 to respond to changes in the sensed environment. For example, the active time lengths may be altered by the user input.
The user input device 480 may include a speed control switch for example or jumper wire on a circuit board on which the conditioner processor 202 is mounted, for example for varying a voltage of the user input signal 481 between a high voltage and a low voltage where a high

-25-voltage may indicate that the user wishes that the system 10 shown in Figure 3 respond quickly using longer active times where a low voltage may indicate that the user wishes that the system respond more slowly using shorter active times.
In other embodiments, the user input device 480 shown in Figure 13 may include push buttons on a user display unit and the user-defined speed may be represented by a value, such as, for example a value between 0 and 100.
The hydraulic pressure sensor 482 is configured to transmit a pressure signal 483 representing the sensed pressure to the conditioner 20. In various embodiments, the pressure signal 483 represents pressure between about 100 and 5000 PSI. The travel speed sensor 484 is configured to transmit a travel speed signal 485 representing the sensed travel speed to the conditioner 20.
In various embodiments, the travel speed signal 485 represents speed between about 0 km/h and 30 km/h. The engine speed sensor 486 is configured to transmit an engine speed signal 487 representing the sensed engine speed to the conditioner 20. In various embodiments, the engine speed signal 487 represents engine speed between about 500 and 4000 RPM.
The hydraulic temperature sensor 498 is configured to transmit a temperature signal 499 representing the sensed temperature to the conditioner 20. The hydraulic temperature sensor 498 may be located in a position on the apparatus 30 shown in Figure 1 that facilitates accurate sensing of a working temperature of the hydraulic fluid.
For example, the hydraulic temperature sensor maybe located at a valve of the hydraulic height cylinder 64 shown in Figure 4. In various embodiments, the temperature signal 499 represents temperature between about 0 and 200 Celsius.
The fuel consumption sensor 488 is configured to transmit a fuel consumption signal 489 representing the sensed fuel consumption rate to the conditioner 20. In various embodiments, the fuel consumption signal 489 represents a fuel consumption rate between about 0 and 20 L/hr.
The accelerometer 490 is configured to transmit an acceleration signal 491 representing the sensed acceleration to the conditioner 20. In various embodiments, the acceleration signal 491

-26-represents one or more sensed acceleration between about 0 and 245 m/s'. The fill level sensor 492 is configured to transmit a fill level signal 493 representing the sensed fill level to the conditioner 20. In various embodiments, the fill level signal 493 represents fill level between 0 and 100%.
The implement identifier device 494 is configured to transmit an implement identifier signal 495 representing the implement identifier to the conditioner 20. In various embodiments, the implement identifier signal 495 represents an implement identifier between 0000 and FFFF. The controller identifier device 496 is configured to transmit a controller identifier signal 497 representing the controller identifier to the conditioner 20. In various embodiments, the controller identifier signal 497 represents a controller identifier between 0000 and FFFF.
In some embodiments, a device may act as the user input device 480, the accelerometer 490, the implement identifier device 494, and/or the controller identifier device 496. For example, in some embodiments, a user may use push buttons on a user display unit of the device to set the user-input, implement identifier, and controller identifier.
In some embodiments, the pressure signal 483, travel speed signal 485, engine speed signal 487, temperature signal 499, fuel consumption signal 489, and fill level signal 493 may be transmitted on an electrical system or controller area network bus (CAN bus) of the propulsion unit 14 shown in Figure 1. For example, any or all of the sensors, such as the hydraulic pressure sensor 482, travel speed sensor 484, engine speed sensor 486, hydraulic temperature sensor 498, fuel consumption sensor 488, and/or fill level sensors 492 may be an existing machine sensor that is included in the propulsion unit 14 and produces a respective signal on the electrical system or CAN bus of the propulsion unit 14 shown in Figure 1.
In the embodiment shown, the signals 481, 483, 485, 487, 499, 489, 491, 493, 495, and 497 shown in Figure 13 may act as the system information signals 49 shown in Figure 3. Each of the signals, 481, 483, 485, 487, 499, 489, 491, 493, 495, and 497 may be one or more analog voltage signals having a voltage proportional to the sensed or measured value. In some embodiments, the signals may be digital signals representing sensed or measured values in binary hexadecimal code for example.

-27-Referring to Figure 14, a flowchart depicting the block of codes 222 for directing the processor circuit 200 shown in Figure 5 to perform time length determining functions is shown. In various embodiments, the block of codes 222 may be executed periodically. For example, in some embodiments, the block of codes 222 may be executed once upon startup of the conditioner 20. In other embodiments, the block of codes 222 may be executed once every minute, for example.
Referring to Figure 14, block 502 directs the conditioner processor 202 shown in Figure 5 to determine system information by directing the conditioner processor 202 to cause the I/O interface 212 to receive the system information signals 481, 483, 485, 487, 499, 491, 493, 495 and 497 at the input ports 254, 256, 258, 259, 263, 264, 266, 268, 270, 272 and 274 respectively and to store a representation of the system information in locations 234 of the variable memory 206 shown in Figure 5. The system information may be stored as a system information record as shown in Figure 15.
Referring to Figure 15, an exemplary system information record is shown at 540. In the embodiment shown, the system information record 540 includes a user input field 542 for storing a representation of user-defined speed, a hydraulic pressure field 544 for storing a representation of sensed pressure, a travel speed field 546 for storing a representation of sensed travel speed, an engine speed field 548 for storing a representation of sensed engine speed, a hydraulic temperature field 549 for storing a representation of sensed temperature of hydraulic fluid, an engine fuel consumption rate field 550 for storing a representation of a sensed fuel consumption rate, an acceleration field 554 for storing a representation of sensed acceleration, a fill level field 556 for storing a representation of a sensed fill level, an implement identifier field 558 for storing a representation of an implement identifier, and a controller identifier field 559 for storing a representation of a controller identifier.
In the embodiment shown in Figure 15, the acceleration field 554 stores a plurality of representations of sensed accelerations over a time period, which is shown as a graph in Figure 15.
Referring back to Figure 14, after block 502 has been completed, block 504 directs the conditioner processor 202 to determine time length information from the system information stored in the system information record 540 shown in Figure 15 and stored in locations 234 of

-28-the variable memory 206 shown in Figure 5 and to store the derived time length information in locations 232 of the variable memory 206.
Block 504 is shown in greater detail in Figure 16 and includes a first block 582 which directs the conditioner processor 202 to determine a base active time length and a base inactive time length. In some embodiments, block 582 may direct the conditioner processor 202 to determine a base active time length based on the contents of the controller identifier field 559 of the system information record 540 shown in Figure 15. For example, block 582 may direct the conditioner processor 202 to read the controller identifier from the controller identifier field 559 of the system information record 540 and use it to find a controller time length record stored in location 236 in the program memory 204 shown in Figure 5. An exemplary representation of a controller time length record, in accordance with one embodiment of the invention, is shown at 600 in Figure 17 and includes a controller identifier field 602 for storing a controller identifier, a base active time length field 606, a minimum active time length field 608, a maximum active time length field 610 and a cycle time length or sampling interval field 612.
The base active time length field 606 shown in Figure 17 stores an active time that facilitates accurate control by the controller identified by the controller identifier field 602 in base conditions (e.g., average expected values for system information). The minimum active time length field 608 and maximum active time length field 610 represent minimum and maximum active times that can facilitate control by the controller identified by the controller identifier field 602. The cycle time length field 612 stores a value representing a sampling interval time between the controller identified by the controller identifier field 602 sampling the position signals and updating the control signals.
Block 582 of Figure 16 directs the conditioner processor 202 of Figure 5 to derive a base active time length from the base active time length field 606 shown in Figure 17 and to derive a base inactive time length by subtracting the base active time length from the cycle time length stored in the cycle time length field 612. Use of these base active and inactive times by the conditioner 20 causes the controller 18 shown in Figure 3 to sample position signals and update control signals during inactive times (e.g. during the inactive times 370, 376, 378, and 414 shown in Figures 11A and 11B).

-29-In various embodiments, a manufacturer of the conditioner 20 may conduct experiments employing various active time lengths when using the conditioner 20 to condition signals produced by the controller 18 to produce output signals for causing the positioning system 22 to move an average agricultural implement such as the header 12. In various embodiments, for example, the manufacturer may find that under normal conditions (i.e., average expected values for system information), the conditioner 20 best facilitates accurate control when the active time length is 20 ms. Accordingly, in various embodiments, the manufacturer may store in the controller time length record 600, a base active time length of 20 ms.
Similarly, the manufacturer may determine minimum and maximum active time lengths through experimentation.
For universal application of the conditioner 20, the controller time length information location 236 of the program memory 204 shown in Figure 5 may store a plurality of controller active time length records for a plurality of different controllers identified by respective controller identifiers. In various embodiments, a user can provide input via the controller identifier device 496 shown in Figure 13 or the controller identifier device 496 may be included in the controller 18 shown in Figures 1 ¨ 3 such that the controller identifier device 496 identifies the controller with which the conditioner is to be used and the time length determining codes will automatically determine appropriate active time and inactive time lengths, cycle time etc. for the identified controller, using the controller active time length record corresponding to the identified controller. Block 582 directs the conditioner processor 202 to store derived base active and base inactive time lengths in the active and inactive time length fields 422 and 424 in the signal time record 420 shown in Figure 12 and stored in locations 232 of the variable memory 206 shown in Figure 5.
In some embodiments, the flowchart shown in Figure 16 may end after block 582.
In other embodiments, the process may continue at block 584, which directs the conditioner processor 202 to adjust values stored in the active time length field 422 and the inactive time length field 424 of the signal time record 420 shown in Figure 12 using information from the system information record 540 shown in Figure 15.

-30-For example, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the user input field 542 of the system information record 540 shown in Figure 15. When the user input field 542 stores a value of TRUE, this indicates that the user-defined speed is high and thus the user wishes that the system 10 shown in Figure 3 react quickly. Therefore, block 584 may direct the conditioner processor 202 to increase the active time length stored in the active time length field 422 in response to the user input field 542 of the system information record 540 shown in Figure 15 being set to TRUE.
In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the hydraulic pressure field 544 and/or the engine speed field 548 of the system information record 540 shown in Figure 15. High hydraulic pressure and low engine speed may indicate high loads that may result in low hydraulic power.
Accordingly, block 584 may direct the conditioner processor 202 to compensate for low hydraulic power by increasing the active time length stored in the active time length field 422 when the hydraulic pressure field 544 and the engine speed field 548 represent high hydraulic pressure and low engine speed and thus represent low hydraulic power.
In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the travel speed field 546 of the system information record 540 shown in Figure 15. High travel speed may indicate that faster lift rates are required.
Accordingly, block 584 may direct the conditioner processor 202 to increase the active time length stored in the active time length field 422 when the travel speed field 546 represents high travel speed.
In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the engine speed field 548 of the system information record 540 shown in Figure 15. Low engine speed may indicate reduced available hydraulic power and slower hydraulic system functions. Accordingly, block 584 may direct the conditioner processor 202 to

-31-compensate for the low power by increasing the active time length stored in the active time length field 422 when the engine speed field 548 represents low engine speed.
In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the temperature field 549 of the system information record 540 shown in Figure 15. High hydraulic temperature may result in lower hydraulic power that may result in low hydraulic function whereas low hydraulic temperature may result in higher hydraulic power.
Accordingly, block 584 may direct the conditioner processor 202 to increase the active time length stored in the active time length field 422 when the temperature field 549 represents high temperature and/or to decrease the active time length stored in the active time length field 422 when the temperature field 549 represents low temperature.
In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the engine fuel consumption rate field 550 and the travel speed field 546 of the system information record 540 shown in Figure 15. In various embodiments, fuel consumption rate may be indicative of engine load. High travel speed at low engine load may indicate that the apparatus 30 shown in Figure 1 is traveling downhill. Low travel speed at high engine load may indicate that the apparatus 30 shown in Figure 1 is traveling uphill. In some embodiments, it may be desirable to slow down auto header height functions when traveling up or down hill, for stability.
Accordingly, in some embodiments, block 584 may direct the conditioner processor 202 to decrease the active time length stored in the active time length field 422 when the engine fuel consumption rate field 550 and the travel speed field 546 indicate that the apparatus 30 shown in Figure 1 is traveling up or down hill. Thus, in some embodiments, block 584 may direct the conditioner processor 202 to decrease the active time length stored in the active time length field 422 when the engine fuel consumption rate field 550 represents high consumption and the travel speed field 546 represents low speed or when the engine fuel consumption rate field 550 represents low consumption and the travel speed field 546 represents high speed.

-32-In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the acceleration field 554 of the system information record 540 shown in Figure 15. High frequency acceleration may be used to determine roughness of terrain. For example, in various embodiments, the roughness of the terrain may be classified as "soft", "medium" or "hard". A high level of high frequency acceleration may indicate that the terrain is rough or hard. In some embodiments, it may be desirable to have slower control and thus shorter active times in rough or hard terrain. Accordingly, block 584 may direct the conditioner processor 202 to decrease the active time length stored in the active time length field 422 when the acceleration field 554 represents a high level of high frequency acceleration.
Low frequency acceleration may be used to determine a pitching motion of the apparatus 30 shown in Figure 1. Accordingly, block 584 may direct the conditioned processor 202 to decrease the active time length stored in the active time length field 422 when the acceleration field 554 represents a low frequency accelerator.
In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the fill level field 556 of the system information record 540 shown in Figure 15. The fill level may be indicative of a mass of the propulsion unit 14. For example, fill level of crop load may add several tons to an operating mass of the propulsion unit 14 shown in Figure 1 as it fills. High mass of the propulsion unit 14 may indicate that header height control is able to be more aggressive without causing the apparatus 30 shown in Figure 1 to pitch.
Accordingly, block 584 may direct the conditioner processor 202 to increase the active time length stored in the active time length field 422 when the fill level field 556 represents a high fill level and thus a large mass of the propulsion unit 14. In various embodiments, the mass of the propulsion unit may be derived from both the fill level and a capacity of the propulsion unit.
Accordingly, an amount by which the active time is varied may depend not only on the fill level but also on a capacity of the propulsion unit 14, which may be determined, for example, using the contents of the controller identifier field 559 of Figure 15, which may correspond to a type of propulsion unit, and a lookup table stored in the program memory 204 shown in Figure 5, for example.

-33-In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to vary the contents of the active time length field 422 of the signal time record 420 shown in Figure 12 based on contents of the implement identifier field 558 of the system information record 540 shown in Figure 15. In various embodiments, the implement identifier may be associated with various inertias of the agricultural implement identified by the implement identifier, for example, by a lookup table stored in the program memory 204 of the conditioner processor circuit 200 shown in Figure 5. Block 584 may direct the conditioner processor 202 to look up in the look up table, inertias of the agricultural implement using the implement identifier from the implement identifier field 558. High inertia may indicate that the agricultural implement is difficult to move. Accordingly, block 584 may direct the conditioner processor 202 to increase the active time length stored in the active time length field 422 when the implement identifier field 558 stores an implement identifier associated with a high inertia.
In some embodiments, block 584 of Figure 16 may direct the conditioner processor 202 to read the minimum and maximum active time length fields 608 and 610 of the controller time length record 600 shown in Figure 17 and limit the adjustments to the active time length to keep the active time length between the minimum and maximum active time lengths.
In some embodiments, block 584 may direct the conditioner processor 202 to vary the contents of the inactive time length 424 of the signal time record 420 shown in Figure 12 to equal a difference between the times represented by the cycle time length field 612 of the controller time length record 600 shown in Figure 17 and the updated active time length field 422, such that the sum of the active time length and the inactive time length remains equal to the cycle time length.
Accordingly, the conditioner processor 202 may be directed to store adjusted or updated time length information in locations 232 of the variable memory 206 shown in Figure 5. As described above, the conditioner processor 202 may be directed to use the time length information stored in the locations 232 of the variable memory 206 when producing the output signals 50 and 52.
Accordingly, the conditioner processor 202 may be directed to use updated time length ,

-34-information, which has been determined using the process depicted by the flowchart shown in Figure 14, when producing the output signals 50 and 52.
Continuous Control Referring to Figure 1, in various embodiments, a user may wish to control the positioning system 22 manually, such as, for example, when the user is finished harvesting and wishes to raise the header 12. In such embodiments, for example, the user causes the controller 18 to continuously transmit output signals 50 and 52 (shown in Figure 3) that are in the up control state to raise the header 12 or to continuously transmit output signals 50 and 52 in the down control state to lower the header 12. The conditioner 20 may normally condition the signals before transmitting output signals to the positioning system 22. However, when the user wishes to manually raise or lower the header 12, in various embodiments, conditioning the continuous control signals may cause the positioning system to move slower than is necessary.
Accordingly, in some embodiments, referring to Figure 3, the conditioner 20 may be configured to determine whether the control signals 46 and 48 represent continuous or manual control by a user and, if the control signals 46 and 48 represent continuous or manual control, to transmit output signals to the positioning system 22, which are not conditioned.
In various embodiments, the conditioner 20 may be configured to simply relay representations of the control signals as output signals to the positioning system 22 when the control signals represent continuous or manual control.
Referring to Figure 18, block of codes 224 shown in Figure 5 for directing the processor circuit 200 to perform continuous control override functions is shown in greater detail.
The blocks of code 224 may be executed after block 302 and before block 304 shown in Figure 7 is executed.
Referring to Figure 18, block 622 directs the conditioner processor 202 to determine whether the control signals meet a continuous control criterion. For example this criterion may be met when the lift and drop control signals 46 and 48 are in an up control state or in a down control state and have not changed for a certain threshold period of time. In various embodiments, during normal automatic control of the positioning system 22 by the controller 18, the controller may not keep the lift and drop control signals 46 and 48 in an up or down control state for

-35-longer than the threshold period of time, due to the speed of the system 10 shown in Figure 3.
Accordingly, when the control signals 46 and 48 have not changed in greater than the threshold period of time, this may be indicative of manual user control.
Referring to Figure 19, in some embodiments, block 622 includes sub-blocks of code including block 642 which directs the conditioner processor 202 to retrieve control signals for the last threshold period of time. This is done by directing the conditioner processor 202 to retrieve a threshold control time from a threshold time record 660 such as shown in Figure 21 from location 238 of the program memory 204. The threshold time record 660 may include a threshold time field 662 representing a threshold time period to be used in determining whether continuous control criterion are met.
Block 642 of Figure 19 may direct the conditioner processor 202 shown in Figure 5 to retrieve all controller signal records from locations 230 of the variable memory 206 that include time fields representing times within the time represented by the threshold time record 660 shown in Figure 20. Accordingly, where the threshold time field 662 stores a time of 1.5 seconds, block 642 may direct the conditioner processor 202 to retrieve controller signal records that include time fields representing times that are within 1.5 seconds of a current time.
In some embodiments, the threshold time may be between about 1.0 seconds and about 2.0 seconds.
Block 644 of Figure 19 then directs the conditioner processor 202 to read the lift and drop valve fields of the controller signal records retrieved in block 642 to determine whether the lift and drop valve fields store equal values for each of the controller signal records retrieved. If the lift and drop values indicated in each of the retrieved records are equal, block 644 directs the conditioner processor 202 to determine that the control signals 46 and 48 meet the continuous control criterion and the conditioner processor 202 is directed to continue at block 624 of Figure 18.
In some embodiments, block 644 of Figure 19 may direct the conditioner processor 202 of Figure 5 to first determine whether the lift and drop valve fields store all FALSE values, and if the conditioner processor 202 determines that the lift and drop valve fields store all false values, then block 644 directs the conditioner processor to determine that the control signals 46 and 48

-36-do not meet the continuous control criterion and directs the conditioner processor 202 to end the process.
If the lift and drop values are not equal, block 644 of Figure 19 directs the conditioner processor 202 of Figure 5 to determine that the control signals 46 and 48 do not meet the continuous control criterion and directs the conditioner processor 202 to end as shown in Figures 18 and 19.
In some embodiments, the value stored in the threshold time field 662 of the threshold time record 660 shown in Figure 20 may be set by a manufacturer of the conditioner 20 for example.
The value stored in the threshold time field 662 may represent a time that the manufacturer has found through experimentation, for example to indicate that a user has taken control of the controller 18. In various embodiments, the time represented by the threshold time field 662 may be large enough such that when the controller 18 is automatically controlling the position of the header 12 shown in Figure 2 during normal use (i.e., while travelling along a field and harvesting crop), block 644 of the flowchart shown in Figure 18 would not direct the conditioner processor to continue at block 624 of the flowchart shown in Figure 19.
Referring back to Figure 18, after block 622 has been executed, if the control signals meet the continuous control criterion, block 624 directs the conditioner processor 202 shown in Figure 5 to produce continuous control signals representing received control signals to the positioning system 22. For example, block 624 may direct the conditioner processor 202 to set the lift and drop output signals 50 and 52 at the output ports 260 and 262 to respective voltages representing the received control signals.
More particularly, block 624 may direct the conditioner processor 202 to retrieve a most recent controller signal record from the locations 230 of the variable memory 206 shown in Figure 5 and cause the output ports 260 and 262 to set the lift and drop output signals 50 and 52 to voltages representing the values of the lift and drop valve fields respectively of the retrieved controller signal record. For example, where the lift and drop valve fields store values of TRUE and FALSE respectively, block 624 may direct the conditioner processor 202 shown in Figure 5 to cause the output ports 260 and 262 of the I/O
interface 212 to set the lift output signal 50 to VH and the drop output signal 52 to VL.

-37-After block 624 is completed, the conditioner processor 202 is directed to return to block 622. If at block 622, the conditioner processor 202 determines that the control signals do not meet the continuous control criterion, the process ends, otherwise block 624 is repeated until the control signals do not meet the continuous control criterion.
In embodiments where the continuous control block of codes 220 is executed after block 302 and before block 304, once execution of the continuous control block of codes 220 has ended , the conditioner processor 202 is directed to execute block 304. Accordingly, in some embodiments, block 304 is executed only if block 622 determines that the control signals do not meet the continuous control criterion.
In some embodiments, block 622 of Figure 18 may direct the conditioner processor 202 shown in Figure 5 to determine that the control signals meet the continuous control criterion in other ways than as described above with reference to Figure 19. For example, in some embodiments, the controller 18 may produce a user control signal 650 that may be intercepted or received at port 274 of the I/O interface 212 of the processor circuit 200 shown in Figure 5. In such embodiments, the control signals received by the conditioner may include the lift control signal 46, the drop control signal 48 and the user control signal 650.
For example, the controller 18 may be configured to set the user control signal 650 shown in Figure 5 to VH when a user is manually controlling the controller 18 and to set the user control signal to VL when a user is not manually controlling the controller 18. Block 622 may direct the conditioner processor 202 to determine whether the control signals meet the continuous control criterion by determining whether the user control signal 650 received at the input port 272 shown in Figure 5 is set to VH. In such embodiments, if the user control signal 650 is set to VH, block 622 may direct the conditioner processor 202 to determine that the control signals meet the continuous control criterion.
Lateral Tilt Referring back to Figure 4, in some embodiments, the positioning system 22 may include a tilt hydraulic cylinder for controlling a lateral tilt of the header 12 shown in Figure 1. Extension of the tilt hydraulic cylinder may cause the front portion 66 of the feeder house 60 shown in Figure 4 to tilt

-38-laterally from left to right (i.e., to rotate the front portion 66 about a pivot point of the front portion by raising a left side of the front portion 66 and lowering a right side of the front portion).
In some embodiments, the controller 18 may be configured to produce tilt control signals in addition to the signals already described, based on the received left and right position signals 40 and 44. The tilt control signals may be configured to control the tilt hydraulic cylinder and thus cause the positioning system 22 to control a lateral tilt of the header 12 shown in Figure 1. In some embodiments, the controller 18 may be configured to cause the tilt control signals to direct the positioning system 22 to tilt the header 12 such that the heights of the left and right sensors 32 and 36 are equal. In some embodiments, the controller 18 may be configured to transmit the tilt control signals directly to the positioning system 22. In some embodiments, the controller 18 may transmit the tilt control signals to the conditioner 20, and the conditioner 20 may relay the tilt control signals to the positioning system 22. In some embodiments, the conditioner 20 may condition the tilt control signals generally as described above having regard to the lift and drop control signals 46 and 48 shown in Figure 3.
Variable Valve Hydraulic Cylinders In various embodiments, other types of height control may be used generally as described above. For example, a height-controlling hydraulic cylinder generally similar to the height-controlling hydraulic cylinder 64 shown in Figure 4 may include, instead of the solenoid controlled lift and drop valves, current controlled variable lift and drop valves. The current controlled variable lift and drop valves may be configured to control a flow of fluid through the valves in proportion to a current applied to inputs on the valves, for example. In some embodiments, the conditioner 20 may be configured to transmit conditioned output signals representing a plurality of active times during which one of the current controlled variable lift and drop valves is caused to open fully and a plurality of inactive times during which the current controlled variable lift and drop valves are caused to close, with each active time being followed by a respective one of the inactive times. The inactive times may be sufficiently long to permit the agricultural implement to settle into a fixed position due to the positioning response time of the positioning system 22.
Controller/Conditioner Processor Circuit

-39-Referring to Figure 21, in alternative embodiments, functions of the controller 18 and the conditioner 20 shown in Figures 1 ¨ 3 and described above may be integrated into a single controller/conditioner 680 in a system 682 shown in accordance with one embodiment in Figure 21. The system 682 may be generally similar to the system 10 shown in Figure 3, except that the system 682 includes the controller/conditioner 680 in place of the controller 18 and the conditioner 20 shown in Figures 1 ¨ 3. The system 682 shown in Figure 21 includes the sensor system 16 and the positioning system 22 of Figures 1 ¨ 3. In various embodiments, the system 682 may also include the system sensors 47 of Figure 3.
The sensors 32 and 36 are configured to produce left and right position signals 40 and 44 representing sensed positions or heights of the header 12 shown in Figure 1 and the controller/conditioner 680 is configured to receive the left and right position signals 40 and 44 and to receive desired position signals representing desired positions or heights of the header 12. In various embodiments, the controller/conditioner 680 is configured to determine a difference between the sensed heights and the desired heights, to derive conditioned lift and drop output signals 684 and 686 from the difference and to transmit the conditioned lift and drop output signals 684 to the positioning system 22.
The lift and drop output signals 684 and 686 are as earlier described and represent a plurality of active times during which the positioning system 22 is instructed to move a header such as the header 12 shown in Figure 1 towards the desired height and a plurality of inactive times during which the positioning system 22 is instructed not to move, each active time being followed by a respective one of the plurality of inactive times, wherein each of the plurality of inactive times is sufficiently long to permit the header 12 shown in Figure 1 to settle into a fixed position due to the positioning response time of the positioning system 22.
Referring to Figure 22, a schematic view of a controller/conditioner processor circuit for implementing the controller/conditioner 680 shown in Figure 21 according to one embodiment is shown generally at 700.

-40-In various embodiments similar aspects of the controller/conditioner processor circuit 700 shown in Figure 22 may be implemented generally similarly to that described above in connection with the processor circuit 200 shown in Figure 5.
Referring to Figure 22, the controller/conditioner processor circuit 700 includes a controller/conditioner processor 702, a program memory 704, a variable memory 706, and an input output ("I/O") interface 712, all of which are in communication with the controller/conditioner processor 702.
The program memory 704 includes a block of codes 720 for directing the controller/conditioner processor 702 to perform signal producing functions and a block of codes 722 for directing the controller/conditioner processor 702 to perform time length determining functions. The program memory 704 may also include at least one location 736 for storing controller time information.
The variable memory 706 includes a plurality of storage locations including locations 726 for storing sensed height information, locations 728 for storing desired height information, locations 730 for storing controller signal information, locations 732 for storing time length information, and locations 734 for storing system information.
The I/O interface 712 may include input ports 750 and 752 for receiving the left and right position signals 40 and 44 and output ports 760 and 762 for producing and transmitting the output signals 684 and 686. In the embodiment shown, the I/O interface 712 also includes input ports 754, 756, 758, 759, 763, 764, 766, 768, 770, and 772 for receiving user input signals, pressure signals, travel speed signals, engine speed signals, temperature signals, fuel consumption signals, acceleration signals, fill level signals, implement identifier signals, and controller identifier signals, respectively such as described previously. In some embodiments, the I/O
interface 712 may also include input ports 774 and 776 for receiving desired position signals.
Controller/Conditioner Signal Producing Referring to Figure 23, block of codes 720 for directing the controller/conditioner processor circuit 700 shown in Figure 22 to produce conditioned lift and drop output signals is shown.

-41-The block of codes 720 begins with block 802 which directs the controller/conditioner processor 702 shown in Figure 22 to receive position signals. In various embodiments, block 802 may direct the controller/conditioner processor 702 to cause the I/O interface 712 to receive the left and right position signals 40 and 44 shown in Figure 21 via the input ports 750, and 752 shown in Figure 22. In some embodiments, block 802 may direct the controller/conditioner processor 702 to convert the position signals into values representing heights or separation distances and to store the values in the locations 726 of the variable memory 706.
In some embodiments, block 802 may direct the controller/conditioner processor 702 shown in Figure 22 to store the representations of the heights as digital values representing heights of between 0 inches and 18 inches. Block 802 directs the controller/conditioner processor to store the representations in a sensed height record 820, such as shown in Figure 24, in locations 726 of the variable memory 706. The sensed height record 820 includes a left sensed height field 822 and a right sensed height field 826 for storing representations of the heights represented by the signals 40 and 44 respectively.
Referring to Figure 23, block 804 then directs the controller/conditioner processor to receive a desired position signal representing a desired position. In some embodiments, a desired height input device may be in communication with the input ports 774 and 776 of the I/O interface 712 shown in Figure 22. In various embodiments, the desired height input device may include one or more user controllable voltage sources for producing one or more desired position signals having voltages representing desired heights for the left and right sensors 32 and 36, shown in Figure 21 for example.
Referring back to Figure 23, in some embodiments, block 804 may direct the controller/conditioner processor 702 shown in Figure 22 to cause the input ports 774 and 776 of the I/O interface 712 to receive left and right desired position signals 830 and 832 having voltages representing desired heights for the left and right sensors 32 and 36. Block 804 may direct the controller/conditioner processor 702 to store in the locations 728 of the variable memory 706 shown in Figure 22, a desired height record 840 as shown in Figure 25 including a

-42-left desired height field 842 and a right desired height field 844 storing values based on the received left and right desired height signals 830 and 832 .
Block 806 of Figure 23 then directs the controller/conditioner processor 702 shown in Figure 22 to derive controller signal information from differences between the desired positions and the sensed positions. For example, block 806 may direct the controller/conditioner processor 702 to determine a left difference between a left sensed height represented by the left sensed height field 822 of the sensed height record 820 shown in Figure 24 and a left desired height represented by the left desired height field 842 of the desired height record 840 shown in Figure 25. Block 806 may also direct the controller/conditioner processor 702 to determine a right difference between the right sensed height represented by the right sensed height field 824 and the right desired height represented by the right desired height field 844 of the desired height record 840 shown in Figure 25.
Referring back to Figure 23, block 806 directs the controller/conditioner processor 702 to store a controller signal record having an up control state in locations 730 of the variable memory 706 shown in Figure 22 (having a lift valve field set to TRUE and a drop valve field set to FALSE) if at least one of the left and right differences represents a sensed height that is less than a desired height and the difference has magnitude greater than a threshold difference.
If neither of the left and right differences represents a sensed height that is less than a desired height and has magnitude greater than the threshold difference and at least one of the left and right differences represents a sensed height that is more than a desired height and has a magnitude greater than the threshold difference then block 806 directs the controller/conditioner processor 702 to store a controller signal record having a down control state in locations 730 of the variable memory 706 shown in Figure 22 (having a lift valve field set to FALSE and a drop valve field set to TRUE). Otherwise, block 806 directs the controller/conditioner processor 702 to store a controller signal record having an off control state in locations 730 of the variable memory 706 shown in Figure 22 (having a lift valve field and drop valve field set to FALSE) Block 806 thus directs the controller/conditioner processor 702 to store a controller signal record having an up control state in locations 730 of the variable memory 706 shown in Figure 22 if one of the left and right differences represents a sensed height less than a desired height

-43-by more than the threshold difference, regardless of the contents of the other of the left and right differences. This may facilitate the controller/conditioner 680 directing the positioning system 22 to avoid a collision between an agricultural implement and the ground.
In various embodiments, the threshold difference may be set by a manufacturer of the controller/conditioner. In some embodiments, the threshold difference may between 0 and 1 inch and may represent a height difference of about 0.5 inches, for example.
Block 808 of Figure 23 directs the controller/conditioner processor 702 to cause the I/O
interface 712 to produce at least one output signal to be provided to the positioning system 22 shown in Figure 21 wherein the at least one output signal represents an active time during which the positioning system 22 is instructed to move the header 12 shown in Figure 1 towards a desired position and an inactive time following the active time during which the positioning system 22 is instructed not to move, wherein the inactive time is sufficiently long to permit the header 12 to settle into a fixed position due to the positioning response time of the positioning system 22. In some embodiments, block 808 may direct the controller/conditioner processor 702 to cause the output ports 760 and 762 to transmit the output signals 684 and 686 to the positioning system 22 shown in Figure 21. Block 808 may be generally similar to block 304 shown in Figure 7 as discussed above. After block 808 has completed, the controller/conditioner processor has completed a cycle and may be directed to return to block 802 to begin a new cycle.
In some embodiments, blocks of code for directing the controller/conditioner processor circuit 700 shown in Figure 22 to perform time length determining may be encoded in the block of codes 722 shown in Figure 22. In various embodiments, the blocks of code similar to those shown at 222 in Figure 14, except that they may be configured to direct the controller/conditioner processor 702 to perform the process. In various embodiments, for the time length determining encoded in the block of codes 722 shown in Figure 22, steps relating to the controller identifier signals may be omitted and the controller time length information may include a single controller time length record associated with the controller/conditioner 680. In such embodiments, the controller time length record associated with the controller/conditioner may include a cycle time length field representing a base cycle time length that facilitates accurate

-44-control of an average positioning system. Further, the controller time length record may not need to include a controller identifier field.
Sensor System Including a Modifier A field over which an agricultural implement is driven may include ground inconsistencies such as, for example, bumps and hills. In various embodiments, a user may wish to be able to sense a position of the agricultural implement relative to the ground at an intermediate location on the agricultural implement. For example, a user may wish to sense a position of the agricultural implement relative to the ground between left and right sensors, which may act as first and second sensors, to avoid driving the agricultural implement into a bump that is located between the left and right sensors.
Referring to Figure 26 there is shown a system 940 according to another embodiment that is generally similar to the system 10 shown in Figures 1 and 3 except that the system 940 includes a different sensor system 950 in place of the sensor system 16. The different sensor system 950 shown in Figure 26 is configured to transmit first and second representative position signals 970 and 972 to the controller 18, which may be received and handled generally as described above in the same way as the left and right position signals 40 and 44 shown in Figures 3 and 21.
Accordingly, the sensor system 950 may be configured to be substitutable for the sensor system 16 shown in Figures 3 and 21, for example The different sensor system 950 includes first and second sensors 952 and 956, an intermediate or central sensor 954, and a modifier 960. Figure 28 shows an agricultural apparatus in accordance with one embodiment, which includes the first, intermediate, and second sensors 952, 954, and 956. In the embodiment shown, the agricultural apparatus 1000 is an agricultural combine harvester including a header 1002 mounted to a propulsion unit 1004.
Referring to Figure 27, the first and second sensors 952 and 956 are mounted to an underside of the header 1002 at first and second spaced apart locations on the header 1002.
The first and second sensors 952 and 956 are located at opposite ends of the header 1002 and act as left and right sensors. The first and second sensors 952 and 956 sense first and second positions or separation distances of the header 1002 relative to the ground at the first and second locations

-45-respectively. The first and second sensors 952 and 956 may be generally similar to the left and right sensors 32 and 36 shown in Figure 1.
Referring still to Figure 27, the intermediate sensor 954 is mounted to an underside of the header 1002 at an intermediate location disposed generally between the first and second sensors 952 and 956. The intermediate sensor 954 senses an intermediate position or separation distance of the header 1002 relative to the ground at the intermediate location. The intermediate sensor 954 may be generally similar to the first and second sensors 952 and 956.
Referring back to Figure 26, the first, intermediate, and second sensors 952, 954, and 956 produce first, intermediate, and second position signals 962, 964, and 966 respectively, representing the first, intermediate, and second positions of the first, intermediate and second locations of the header 1002 relative to the ground.
The modifier 960 receives the first, intermediate, and second position signals 962, 964, and 966 and, when the intermediate position meets a reference surface proximity criterion, transmits to the controller at least one modified representative position signal representing at least one modified position that differs from the first and second positions.
The reference surface proximity criterion may be met for example when the intermediate position is indicative of the header 1002 shown in Figure 27 getting close to the ground and the modifier 960 may, when the intermediate position meets the reference surface proximity criterion, cause the first representative position signal 970 to represent a position closer to the ground than the first position and/or cause the second representative position signal 972 to represent a position closer to the ground than the second position.
Accordingly, in various embodiments, when the intermediate position is indicative of the header 1002 shown in Figure 27 getting close to the ground, the modifier 960 modifies the first and second representative position signals 970 and 972 such that the controller 18 is more likely to cause the header 1002 to be raised. In various embodiments, this may facilitate avoidance of impact of the header 1002 with the ground.

-46-Referring to Figure 28, a modifier processor circuit for implementing the modifier 960 shown in Figure 26 according to one embodiment is shown generally at 1040. The modifier processor circuit 1040 includes a modifier processor 1042, a program memory 1044, a variable memory 1046, and an I/O interface 1048, all of which are in communication with the modifier processor 1042.
The program memory 1044 includes a block of codes 1050 for directing the modifier processor 1042 to perform position signal modifying functions. The variable memory 1046 includes a plurality of storage locations including locations 1066 for storing position information and locations 1068 for storing representative position information. The I/O interface 1048 includes input ports 1080, 1082, and 1084 for receiving the second, intermediate, and first position signals 966, 964, and 962 and output ports 1090 and 1092 for producing and transmitting the first and second representative position signals 970 and 972.
Similar elements of the modifier processor circuit 1040 shown in Figure 28 may be implemented generally similarly to those described above in connection with the processor circuit 200 shown in Figure 5.
Referring to Figure 29, the block of codes 1050 for directing the modifier processor circuit 1040 shown in Figure 28 to perform position signal modifying functions, begins with block 1112 which directs the modifier processor 1042 shown in Figure 28 to receive at least one signal representing the first, second, and intermediate positions relative to the ground of the first, second, and intermediate locations respectively of the header 1002 shown in Figure 27. Block 1112 directs the modifier processor 1042 shown in Figure 28 to cause the I/O
interface 1048 to receive the first, intermediate, and second position signals 962, 964, and 966 via the input ports 1084, 1082, and 1080 shown in Figure 28 and to store a position record based on the first, intermediate, and second position signals in the locations 1066 of the variable memory 1046 shown in Figure 28.
Referring to Figure 30, an exemplary position record is shown at 1140 and includes a first position field 1142, a second position field 1144, and an intermediate position field 1146. Block 1112 directs the modifier processor 1042 to store digital representations of positions

-47-represented by the first, second, and intermediate position signals 962, 966, and 964 shown in Figure 26 in the first, second, and intermediate position fields 1142, 1144, and 1146 of the position record 1140. The digital representations act as representations of the first position, the second position, and the intermediate position of the first, second, and intermediate locations of the header 1002 shown in Figure 27.
Referring back to Figure 29, block 1114 then directs the modifier processor 1042 of Figure 28 to determine whether the intermediate position meets a reference surface proximity criterion. To do this, block 1114 directs the modifier processor 1042 to retrieve a threshold intermediate value from the variable memory 1046. The threshold intermediate value represents a threshold intermediate distance under which the header 1002 shown in Figure 27 is considered to be close to the ground. The threshold intermediate value may be previously set by a user of the modifier 960 such as, for example, by an input device. The threshold intermediate value may represent a separation distance of about 0.5 inches, for example.
Block 1114 of Figure 29 directs the modifier processor 1042 of Figure 28 to determine whether the intermediate position represented by the intermediate position field 1146 of the position record 1140 shown in Figure 30 represents a separation distance that is less than the threshold intermediate distance represented by the threshold intermediate value. If the intermediate position represents a separation distance that is less than the threshold intermediate distance, block 1114 of Figure 29 directs the modifier processor 1042 to proceed to block 1116. If the intermediate position represents a separation distance that is not less than the threshold intermediate distance, block 1114 directs the modifier processor 1042 to proceed to block 1118.
In an alternative embodiment, the reference surface proximity criterion may be met only if the intermediate position represents a separation distance of less than the threshold intermediate distance for more than a threshold period of time, such as 3 seconds, for example.
In the embodiment shown in Figure 30, the intermediate position field 1146 contains a representation of an intermediate position of 0.3 inches relative to the ground which represents an intermediate separation distance of 1.5 inches which is less than the threshold intermediate

-48-distance of 0.5 inches. Thus, block 1114 of Figure 29 directs the modifier processor 1042 of Figure 28 to proceed to block 1116.
Referring to Figure 29, block 1116 directs the modifier processor 1042 of Figure 28 to produce and transmit to the positioning system at least one modified representative position signal representing at least one modified position that differs from the first and second positions.
In some embodiments, block 1116 directs the modifier processor 1042 to determine an intermediate deviation by determining a difference between the intermediate position and the threshold intermediate distance. In the embodiment shown in Figure 30, the intermediate position field 1146 represents a separation distance of 0.3 inches. As discussed above, the threshold intermediate value represents a separation distance of 0.5 inches and so block 1116 directs the modifier processor 1042 to determine that the intermediate deviation is 0.5 inches ¨
0.3 inches = 0.2 inches. The intermediate deviation determined at block 1116 represents a proximity of the intermediate location of the header 1002 shown in Figure 27 to the ground.
Referring still to Figure 29, block 1116 then directs the modifier processor 1042 to derive a representative position record, such as exemplary representative position record 1180 shown in Figure 31, and to store the representative position record 1180 in locations 1068 of the variable memory 1046 shown in Figure 28.
Referring to Figure 31, the representative position record 1180 includes a first representative position field 1182 for storing representation of a first representative position and a second representative position field 1184 for storing a representation of a second representative position.
Referring to Figure 29, block 1116 directs the modifier processor 1042 to store in the first representative position field 1182 of the representative position record 1180 shown in Figure 31, a representation of a difference between the first position represented by the first position field 1142 of the position record 1140 shown in Figure 30 and the intermediate deviation discussed above. Accordingly, where the first position field 1142 represents 1.3 inches of separation distance and the intermediate deviation is 0.2 inches, as calculated above, block

-49-1116 directs the modifier processor 1042 to store a representation of the difference (i.e., 1.1 inches) in the first representative position field 1182 shown in Figure 31. In some embodiments, block 1116 may direct the modifier processor 1042 to scale the intermediate deviation up or down before subtracting it from the first position represented by the first position field 1182 and storing the difference in the first representative position field 1182 shown in Figure 31.
Block 1116 similarly directs the modifier processor 1042 to store in the second representative position field 1184 a representation of a difference between the second position represented by the second position field 1144 of the position record 1140 shown in Figure 30 and the intermediate deviation. The positions represented by the contents of the first and second representative position fields 1182 and 1184 differ from the first and second positions and act as modified positions.
Block 1116 directs the modifier processor 1042 to cause the output ports 1090 and 1092 of the I/O interface shown in Figure 28 to cause the first and second representative position signals 970 and 972 to represent the modified positions represented by the first and second representative position fields 1182 and 1184 shown in Figure 31. In various embodiments, block 1116 may direct the modifier processor 1042 to cause the output ports 1090 and 1092 to set the first and second representative position signals 970 and 972 to respective voltages representing the modified positions represented by the first and second representative position fields 1182 and 1184.
In various embodiments, the modified positions represent an offset of the first and second positions wherein a magnitude of the offset is based on a proximity of the intermediate position to the ground. In various embodiments, because the modified positions represent positions that are closer to the ground than the first and second positions, the controller 18 shown in Figure 26 receiving the first and second representative position signals 970 and 972 may be more likely to cause the positioning system 22 to move the header 1002 shown in Figure 27 upwards in response to the first and second representative position signals 970 and 972 than if the controller 18 received the first and second position signals 962 and 966.

-50-In some embodiments, the intermediate position may not meet the reference surface proximity criterion. For example, the intermediate position represented by the intermediate position field 1146 shown in Figure 30 may be greater than the threshold intermediate distance and thus block 1114 of Figure 29 directs the modifier processor 1042 of Figure 28 to proceed to block 1118.
Block 1118 of Figure 29 directs the modifier processor 1042 of Figure 28 to produce and transmit to the controller 18 shown in Figure 26 at least one representative position signal representing the first and the second positions.
In various embodiments, block 1118 of Figure 29 directs the modifier processor 1042 of Figure 28 to derive a representative position record, such as exemplary representative position record 1200 as shown in Figure 32, and to store the representative position record 1200 in locations 1068 of the variable memory 1046 shown in Figure 28. Referring to Figure 32, the representative position record 1200 has the same format as the representative position record 1180 shown in Figure 31. Block 1118 of Figure 29 directs the modifier processor 1042 of Figure 28 to copy the representations of the first and second positions from the first and second position fields 1142 and 1144 of the position record 1140 shown in Figure 30 into first and second representative position fields 1202 and 1204 of the representative position record 1200 shown in Figure 32.
Block 1118 of Figure 29 then directs the modifier processor 1042 of Figure 28 to cause the output ports 1090 and 1092 of the I/O interface shown in Figure 28 to cause the first and second representative position signals 970 and 972 to represent the positions represented by the first and second representative position fields 1202 and 1204 shown in Figure 32.
Accordingly, block 1118 directs the modifier processor 1042 to relay the first and second positions represented by the received first and second positions signals 962 and 966 on to the controller 18 shown in Figure 26.
Referring to Figure 29, after block 1116 or block 1118 has been executed, the modifier processor 1042 is directed to return to block 1112.

-51-Alternatively, a sensor system similar to the sensor system 950 shown in Figure 26 may include one or more intermediate sensors. For example, the sensor system may include two or more intermediate sensors configured to sense respective intermediate positions of respective intermediate locations of the header 1002 shown in Figure 27. In such an embodiment, the modifier 960 is configured to apply a selection criterion to the intermediate positions represented by intermediate sensor signals to select one of the intermediate positions and then use it as the intermediate position in the process shown in Figure 29. For example, applying the selection criterion may involve selecting the intermediate position that represents a separation distance that is closest to the ground.
In an alternative embodiment, the header 1002 shown in Figure 27 includes a cutter bar that is configured to be pushed up by rising ground or terrain. In such an embodiment, a hydraulic pressure sensor for sensing hydraulic pressure in a hydraulic cylinder coupled to the cutter bar may act as the intermediate sensor. The pressure sensor may sense position or height of the header 1002 by sensing backpressure or differential pressure in the hydraulic cylinder coupled to the cutter bar.
Header controller Referring to Figure 33, an agricultural apparatus in accordance with another disclosed embodiment is shown at 1240 and includes a propulsion unit 1242 and an agricultural implement or header 1244 mounted on the propulsion unit. The propulsion unit 1242 and the header 1244 are generally configured as described above in connection with agricultural apparatus 30 shown in Figure 1. The header 1244 includes a frame 1246 and a first sensor 1248 on a right hand side of the header frame and a second sensor 1250 on the left hand side of the header frame. In some embodiments the header 1244 may further include an intermediate sensor (not shown) disposed between the first sensor 1248 and the second sensor 1250, as described above in connection with Figure 27. The first and second sensors 1248 and 1250 each produce a position signal representative of sensed position or height of the header 1244 relative to the ground at the respective sensors.
In this embodiment the header 1244 includes a header controller 1260 disposed on-board the header and operably configured to receive the signals from the first and second sensors 1248 and

-52-1250 to control other operations of the header as described later herein. In other embodiments the header may be controlled by a controller disposed on the propulsion unit 1242.
The propulsion unit 1242 also includes a propulsion unit controller 1270 operable to control functions of the propulsion unit. In this embodiment the propulsion unit controller 1270 is located in the cab of the propulsion unit 1242 and may include a touch display for displaying operating information and receiving input from an operator of the propulsion unit. A
further display and input device 1262 is also disposed in the cab for displaying information and receiving input for controlling functions of the header controller 1260. The display/input device 1262 may also be implemented as a touch screen display. The display/input device 1262 thus operates as a remote display and input device for the header controller 1260.
The propulsion unit 1242 further includes a positioning system 1280 operable to control hydraulic actuators that cause the frame 1246 to be raised or lowered with respect to the propulsion unit 1242 and thus the ground. The hydraulic actuators may include a hydraulic cylinder 1282 on the left hand side of the frame 1246 that works in conjunction with a similar hydraulic cylinder on the right hand side (not visible in Figure 33) to raise or lower the frame with respect to the propulsion unit 1242. The left hand side hydraulic cylinder 1282 and corresponding right hand side hydraulic cylinder may be controlled together to raise the overall header height.
Alternatively, these hydraulic cylinders may also be independent controlled to control the lateral tilt as described above. The hydraulic actuators may also include a hydraulic cylinder 1284 that raise or lower a reel 1252 of the header 1244. The positioning system 1280 may produce signals for controlling lift and drop solenoid valves, which cause the hydraulic cylinder 1254 to extend or retract as described above in connection with Figure 4 to raise or lower the header 1244.
The position sensors 1248 and 1250, the header controller 1260, the display/input device 1262, the propulsion unit controller 1270, and the positioning system 1280 together form a control system for the agricultural apparatus 1240. The control system is shown together with connections between the various components in Figure 34 at 1300. Referring to Figure 33, the first sensor 1248 produces a first position signal 1302 and the second sensor 1250 produces a second position signal 1304, which are received at the header controller 1260. The header controller 1260 is in communication with the display/input device 1262 and the propulsion unit controller 1270 via a

-53-controller area network bus (CAN bus 1308) and is capable of receiving and transmitting data over the CAN bus. The positioning system 1280 has inputs 1310 and 1312 for receiving command signals from either the header controller 1260 (via the display/input device 1262) or from the propulsion unit controller 1270. The positioning system 1280 further has outputs 1314 and 1316 for producing lift and drop control signals for controlling solenoid valves that actuate the hydraulic cylinder 1282 to raise or lower the header frame 1246.
In one embodiment the header controller 1260 is implemented using the processor circuit shown in Figure 35. Referring to Figure 35, the header controller includes a microprocessor 1340, a program memory 1342, a variable memory 1344, and an input output ("I/O") interface 1346, all of which are in communication with the microprocessor 1340. The program memory 1342 includes a block of codes 1350 for directing the microprocessor 1340 to perform signal producing functions and a block of codes 1352 for directing the microprocessor to perform time length determining functions. The program memory 1342 may also include at least one location 1354 for storing controller time information. The variable memory 1344 includes a plurality of storage locations including locations 1360 for storing sensed height information, locations 1362 for storing desired height information, locations 1364 for storing controller signal information, locations 1366 for storing time length information, and locations 1368 for storing system information. The I/O
interface 1346 includes input ports 1370 and 1372 for receiving the left and right position signals 1302 and 1304. The I/O
interface 1346 also includes a CAN bus interface 1374 for communicating with the propulsion unit controller 1270 and the display/input device 1262.
A process implemented by the microprocessor 1340 of the header controller processor circuit for controlling positioning of the header 1244 is shown generally at 1400 in Figure 36. Referring to Figure 36, the process begins at block 1402, which directs the microprocessor 1340 to receive the left and right position signals 1302 and 1304 at the input ports 1370 and 1372 of the I/O interface 1346. In embodiments where the position signals produced by the sensors 1248 and 1250 are analog signals, the I/O interface 1346 may further perform digital to analog conversion to convert the position signals into values representing heights or separation distances.
Block 1402 also directs the microprocessor 1340 to store the signal values in the location 1360 of the variable memory 1344, as generally described above in connection with the controller processor circuit 700 in Figure 22.

-54-Block 1404 then directs the microprocessor 1340 to cause the I/O interface 1346 to receive desired position signals. In this embodiment, the desired position signals may be received over the CAN bus 1308 at the CAN bus interface 1374. In one embodiment, the desired position signal is provided by operator input at the display/input device 1262 and communicated over the CAN
bus 1308 to the CAN bus interface 1374. In other embodiments, operator input may be received at the propulsion unit controller 1270 and communicated to the CAN bus interface 1374 via the CAN bus 1308.
In this embodiment, the desired position signals transmitted by the display/input device 1262 over the CAN bus 1308 may be also be received at the propulsion unit controller 1270 and used to update information associated with operations of the propulsion unit 1242.
Similarly, the desired position signals transmitted by the propulsion unit controller 1270 over the CAN bus 1308 may be received at the display/input device 1262 and used to update displayed information associated with the position of the header 1260.
The process 1400 then continues at block 1406, which directs the microprocessor 1340 to cause the I/O interface 1346 to receive system information from the propulsion unit controller 1270 over the CAN bus 1308. As described above in connection with Figure 13, various system information signals 481, 483, 485, 487, 499, 489, 491, 493, 495, and 497 may be produced by the agricultural apparatus and thus provide operating information associated with the agricultural apparatus 1240.
Operating conditions of the agricultural apparatus 1240 such as hydraulic pressure, travel speed, engine speed, hydraulic fluid temperature, fuel consumption, acceleration, hopper fill level, the type of header, and the type of propulsion unit controller, may all have some impact on position control of the header 1244 as described above.
Block 1408 then directs the microprocessor 1340 to derive controller signal information from differences between the desired positions and the sensed positions. For example, block 1408 may direct the microprocessor 1340 to determine a left difference between a left sensed height and a left desired height and a right difference between the right sensed height and the right desired height.

-55-Block 1410 then directs the microprocessor 1340 to condition the output signals generally as described above in connection with Figure 11A and 11B. The conditioned output signals have a control state that alternates successively between an active time during which the output signal causes the positioning system to move the agricultural implement towards the desired position and an inactive time during which the output signal causes the positioning system to discontinue movement of the agricultural implement. The active time and inactive time are selected as described above and based on a positioning response time of the positioning system and are operable to permit the agricultural implement to settle in a non-transient position during the inactive time.
In some embodiments, block 1410 further directs the microprocessor 1340 to take one or more operating conditions of the agricultural apparatus 1240 into account, based on the received system information. For example, high hydraulic pressure and low engine speed may indicate high loads that may result in low hydraulic power, which may be compensated by increasing the active time length to allow more time for movement of the hydraulic cylinder 1282. Other operating conditions may be taken into account as described above in connection with Figures 13 to 20.
Block 1412 then directs the microprocessor 1340 to transmit the output signals to the display/input device 1262 over the CAN bus 1308. In the embodiment shown, the display/input device 1262 may act as a relay device, receiving output signals as values transmitted over the CAN bus 1308 and producing signals for receipt at the input 1310 for controlling the positioning system 1280 to raise or lower the header 1244 via the hydraulic cylinder 1282. In this embodiment, the display/input device 1262 may include a processor circuit that receives the output signals on the CAN bus 1308.
Blocks 1422 and 1424 provide further details of a process 1420 that directs the processor circuit of the display/input device 1262 to produce command signals in a format suitable for receipt at the input 1310 of the positioning system 1280. In this embodiment, the header controller 1260 both generates and conditions the output signals transmitted to the positioning system 1280.
The positioning system 1280 executes a remaining process portion 1430. At block 1432, the positioning system 1280 receives the command signals at the input 1310 and at block 1434 produces corresponding lift and drop signals at the outputs 1314 and 1316 for controlling solenoid valves that supply hydraulic fluid to the hydraulic cylinder 1282, as generally described above.

-56-The output signals transmitted by the header controller 1260 may further be received by the propulsion unit controller 1270 on the CAN bus 1308 and may be used to update the operating information displayed to the operator on the controller display. In the embodiment shown, the propulsion unit controller 1270 may also produce signals for receipt at the input 1312 of the positioning system 1280 to permit the operator of the agricultural apparatus 1240 to override the position as controlled by the header controller 1260. As an example, the operator may decide to exercise continuous control of the header height by completely lifting the header at the end of a run. Alternatively, the operator may observe an obstruction ahead that the position control system could not be expected to avoid and may intervene to lift the header 1244 to avoid potential collision between the header and the ground.
In the embodiment described above in connection with Figures 33 ¨ 35, position control of the header 1244 is thus implemented by the header controller 1260, which is located on the header.
The propulsion unit controller 1270 retains overall control of the agricultural apparatus 1240, while permitting the header controller 1260 to attend to position control functions.
If the operator of the agricultural apparatus 1240 decides to intervene, inputs received at the propulsion unit controller 1270 may be used to override the position control functions being implemented on the header controller 1260. The propulsion unit controller 1270 remains aware of the position control being implemented by the header controller 1260 by receiving header positioning output signals over the CAD bus 1308. Similarly, the header controller 1260 is able to respond to operator interventions and/or factor operating conditions of the agricultural apparatus 1240 into the control of the height of the header 1244 through system information received from the propulsion unit controller 1270 on the CAN bus 1308. Accordingly, while the output signals derived by the header controller 1260 are used to control the positioning system 1280, user input/output at the display/input device 1262 and/or the propulsion unit controller 1270 is also taken into account.
While the above has been described having regard to an agricultural combine harvester including a header, which acts as an agricultural implement, mounted to a propulsion and processing unit, in various embodiments, similar methods, systems and apparatuses to those described above may be used in connection with other agricultural implements, such as, for example, a spray boom on a power unit.

-57-While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.

Claims (10)

WHAT IS CLAIMED IS:

1. An apparatus for controlling positioning of an agricultural implement, the agricultural implement being mounted on a propulsion unit having a positioning system for positioning the agricultural implement, the apparatus comprising:
a controller operably configured to receive a position signal from at least one position sensor, the position signal representing a position of the agricultural implement relative to the ground, the position sensor and the controller each being disposed on the agricultural implement;
wherein while a difference between the position of the agricultural implement and a desired position of the agricultural implement is greater than a threshold difference, the controller is operably configured to produce and transmit an output signal to the positioning system of the propulsion unit, the output signal having a control state that alternates successively between:
an active time during which the output signal causes the positioning system to move the agricultural implement towards the desired position; and an inactive time during which the output signal causes the positioning system to discontinue movement of the agricultural implement, wherein the active time and inactive time are selected based on a positioning response time of the positioning system and are operable to permit the agricultural implement to settle in a non-transient position during the inactive time while receiving the position signal from the at least one position sensor representing an updated current position of the agricultural implement.

2. The apparatus of claim 1 wherein the controller is operably configured to produce and transmit an output signal to the positioning system by transmitting an output signal over a vehicle communications bus implemented on the propulsion unit.

3. The apparatus of claim 2 further comprising a display disposed on the propulsion unit and in communication with the vehicle communications bus for displaying operating information associated with the controller on the agricultural implement, and wherein the display is operably configured to receive the output signal from the controller and to produce command signals for controlling the positioning system.

4. The apparatus of claim 1 wherein the propulsion unit comprises a controller operable to control functions of the propulsion unit and wherein the controller on the propulsion unit is operably configured to receive the output signals from the controller on the header for updating operating information associated with the agricultural implement.

5. The apparatus of claim 4 wherein the controller on the propulsion unit is operably configured to receive operator input associated with controlling positioning of the agricultural implement and to transmit the operator input to the controller on the agricultural implement.

6. A method for controlling positioning of an agricultural implement, the agricultural implement being mounted on a propulsion unit having a positioning system for positioning the agricultural implement, the method comprising:
receiving a position signal from at least one position sensor at a controller, the position signal representing a position of the agricultural implement relative to the ground, the position sensor and the controller each being disposed on the agricultural implement;
while a difference between the position of the agricultural implement and a desired position of the agricultural implement is greater than a threshold difference, causing the controller to produce and transmit an output signal to the positioning system of the propulsion unit, the output signal having a control state that alternates successively between:
an active time during which the output signal causes the positioning system to move the agricultural implement towards the desired position; and an inactive time during which the output signal causes the positioning system to discontinue movement of the agricultural implement, wherein the active time and inactive time are selected based on a positioning response time of the positioning system and are operable to permit the agricultural implement to settle in a non-transient position during the inactive time while receiving the position signal from the at least one position sensor representing an updated current position of the agricultural implement.

7. The method of claim 6 wherein causing the controller to produce and transmit an output signal to the positioning system comprises causing the controller to transmit an output signal over a vehicle communications bus implemented on the propulsion unit.

8. The method of claim 7 wherein operating information associated with the controller on the agricultural implement is displayed on a display disposed on the propulsion unit and in communication with the vehicle communications bus, and further comprising causing the display to receive the output signal from the controller and to produce command signals for controlling the positioning system.

9. The method of claim 6 wherein the propulsion unit comprises a controller operable to control functions of the propulsion unit and further comprising causing the controller on the propulsion unit to receive the output signals from the controller on the header for updating operating information.

10. The method of claim 9 further comprising receiving operator input at the controller on the propulsion unit associated with controlling positioning of the agricultural implement and transmitting the operator input to the controller on the agricultural implement.