Patent Publication Number: US-2019183030-A1

Title: Stabilizer control for an agricultural implement

Description:
FIELD OF THE DESCRIPTION 
     The present description relates to controlling stabilizer wheels on an agricultural implement. More specifically, the present description relates to controlling the position of stabilizer wheels, relative to an implement frame, and based on a depth control setting for the agricultural implement. 
     BACKGROUND 
     There are a variety of different types of agricultural implements that have stabilizer wheels. For instance, a tillage implement often has a main depth control system which includes a set of actuators coupled to weight bearing wheels. The position of the actuators controls a position of a frame of the tillage implement, relative to the weight bearing wheels. This, therefore, controls a depth of engagement of the tillage implement with the soil. 
     The main depth control actuators can be actuated to lift the entire implement out of the ground for travel, during headland turns within a field, etc. Therefore, the main control actuators have a relatively large range of movement so that they can move the weight bearing wheels, relative to the frame of the implement, from a first extreme position where the tillage implement is fully engaged (at maximum depth) with the soil, to a second extreme position where the tillage implement is raised so that it is completely out of engagement with the soil. 
     Stabilizer wheels are different from the weight bearing wheels in the main depth control system. Stabilizer wheels are often found on a certain portion of a tillage implement (such as on the front of the tillage implement) and are used to level the tillage implement when it is engaged with the soil. For instance, an operator may know that he or she will be tilling at a depth of 4 inches. The operator will then set a position of the stabilizer wheels, relative to the frame of the tillage implement, so that the tillage implement will be relatively level when tilling at a 4 inch depth. 
     In current systems, the position of the stabilizer wheels relative to the frame of the tillage implement is set by a mechanical turn buckle. Therefore, the operator adjusts the mechanical turn buckle so that the stabilizer wheels are at a desired position, relative to the frame of the tillage implement, and based on the operator&#39;s knowledge of the desired depth at which the operator will be tilling. By way of example, if the operator will be tilling at a 4 inch depth, then the stabilizer wheels may be set to a first position. However, if the operator is tilling at a 6 inch depth, the stabilizer wheels may be set to a second position. 
     Often, the stabilizer wheels are set before the operation begins, and are not adjusted until the operation is complete. This is because the stabilizer wheels are often adjusted by the mechanical turn buckle adjustment which requires the operator to exit the operator compartment and adjust the turn buckles to change the position of the stabilizer wheels relative to the frame of the tillage implement. 
     It should also be noted that stabilizer wheels, because they are used for leveling the tillage implement when it is engaged with the soil, often have a range of movement relative to the frame of the tillage implement that is less than the range of movement for the main depth control actuators. This is because the main depth control actuators need to be moved between the two extreme positions discussed above, while the stabilizer wheels only need to be moved through a narrower range of movement, to level the tillage implement when it is engaged in the soil. 
     The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
     SUMMARY 
     A main depth control input is detected, that indicates a depth of a soil engaging implement. A corresponding position of a stabilizer depth control actuator is identified, and a control signal is generated to control a main depth control actuator based on the main depth setting detected, and to control a stabilizer depth control actuator based upon the corresponding position identified. This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial block diagram, partial pictorial illustration, of one example of a tillage implement being towed by a towing vehicle. 
         FIG. 2  is a pictorial illustration of one example of a stabilizer depth control actuator. 
         FIG. 3  is a block diagram showing one example of the towing vehicle and towed implement. 
         FIGS. 4A and 4B  (collectively referred to herein as  FIG. 4 ) illustrate a flow diagram showing one example of the operation of a depth control system. 
         FIG. 5  is a flow diagram showing one example of the operation of the control system in identifying a position of a stabilizer depth control actuator based upon a detected main depth setting. 
         FIGS. 6 and 7  show examples of hydraulic circuits. 
         FIGS. 8-10  show examples of mobile devices that can be used to implement all or part of the depth control system. 
         FIG. 11  is a block diagram showing one example of a computing environment that can be used to implement all or part of the depth control system. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a partial block diagram partial pictorial illustration of towing vehicle  100  towing a tillage implement  102 . Towing vehicle  100  is illustratively coupled to implement  102  by link  104 . Towing vehicle  100  can be, for instance, a tractor or another towing vehicle. 
     Implement  102  illustratively has a main frame  106  that supports a set of ground-engaging elements  108 . The depth of engagement with the soil of ground-engaging elements  108  is controlled by a main depth control system generally illustrated at  110 . Main depth control system  110  illustratively includes a set of main weight bearing wheels  112  that are coupled to main frame  108  through a set of movable linkages  114 . Movement of the linkages  114  relative to frame  106  is illustratively driven by one or more different main depth control actuators (which may be hydraulic cylinders or other actuators). The cylinders can illustratively be actuated to raise or lower main frame  106  relative to wheels  112  and to thus change the depth of engagement of soil-engaging elements  108  with the soil over which implement  102  is traveling. 
     In addition, the main depth control actuators can move the relative position of wheels  112 , relative to frame  106 , between two extreme positions. The first extreme position is where wheels  112  are positioned so that they lift frame  106  high enough so that soil-engaging elements  108  are out of engagement with the ground. In one example, they can be raised several inches out of the ground so that implement  102  is positioned for travel to a different field, or to make headland turns in a field being tilled, etc. The second extreme position is where frame  106  is lowered relative to wheels  112  so that soil-engaging elements  108  are engaged at a maximum depth within the soil over which implement  102  is traveling. Thus, the main depth control actuators may be actuatable to move frame  108  through a range of vertical movement that is approximately 20 inches. This is just one example and the range of movement enabled by the main depth actuators can vary widely.  FIG. 1  also shows that, in the example illustrated, implement  102  illustratively has a set of stabilizer wheel assemblies illustrated generally at  116  and  118 . Stabilizer wheel assemblies  116  and  118  illustratively include stabilizer wheels  120  and  122 , and a movable support assembly  124  and  126 . Assemblies  124  and  126  support wheels  120  and  122 , respectively, for movement relative to frame  106 . The position of each of the movable assemblies is illustratively driven by a corresponding stabilizer depth control actuator (e.g., actuators  128  and  130 , respectively). In one example, actuators  128  and  130  are illustratively hydraulic actuators. 
     Stabilizer wheels  120  and  122  are illustratively used to level implement  102  when it is in engagement with the ground. Therefore, the range of movement of the assemblies  124 - 126  and actuators  128 - 130  can move the position of stabilizer wheels  120 - 122  between two extreme positions. The two extreme positions, however, define a range of vertical movement of wheels  120 - 122 , relative to frame  106 , that is less than the range of movement of the main depth control wheels  112  relative to frame  106 . 
     In one example, and as is described in greater detail below, actuators  128 - 130  can be independently actuated, independently of the main depth control actuators, and independently of one another. Also, in one example, once the operator sets a depth for the main depth control system  110 , a control system can automatically identify a corresponding position of the stabilizer wheels  120 - 122 , and can automatically control actuators  128 - 130  to move the stabilizer wheels to that position in order to level implement  102 . Further, in one example, the operator can individually control cylinders  128 - 130  to level implement  102  based on the operator&#39;s observation. These scenarios are all described in greater detail below. 
       FIG. 2  is a pictorial illustration showing one example of a stabilizer wheel (stabilizer wheel  120 ), a portion of the movable support assembly (or linkage)  124 , and the stabilizer depth control actuator  128 . In the example illustrated, actuator  128  is illustratively a hydraulic cylinder that receives hydraulic fluid under pressure through one or more hydraulic valves  140 . The hydraulic valves are illustratively controlled from a control system (which may be on towing vehicle  100  or on implement  102 ) that generates a set of stabilizer depth control signals  142 . As hydraulic cylinder  128  is lengthened, this causes rotation of assembly  124  about pivot point  144  generally in the direction indicated by arrow  146 . As cylinder  128  is shortened, it causes pivotal movement in the opposite direction. Thus, when assembly  124  is moved in the direction indicated by arrow  146 , this causes stabilizer wheel  120  to move downwardly relative to the main frame  106 , thus lifting a portion of main frame  106  relative to the soil over which implement  102  is traveling. When assembly  124  moves in the direction opposite of arrow  146 , this causes wheel  120  to move upwardly relative to frame  106 , to lower the frame relative to the ground. 
       FIG. 3  is a block diagram showing one example of towing vehicle  100  and towed implement  102 , in more detail. Some of the items in  FIG. 3  are similar to those shown in previous FIGS. and they are similarly numbered. It can be seen in the example shown in  FIG. 3  that towing vehicle  100  is connected to towed implement  102  by link  104 . In the example shown in  FIG. 3 , towing vehicle  100  illustratively includes one or more processors  156 , communication system  158 , depth control system  160 , data store  161 , operator interface mechanisms  162 , and other towing vehicle functionality  164 . Depth control system  160 , itself, can include main depth control logic  166 , setting identifier logic  167 , stabilizer wheel depth control logic  168 , signal generator logic  169 , correlation modification logic  171 , and it can include other items  170 . It will be noted that, for the sake of the present description, depth control system  160  is disposed on towing vehicle  100 . However, it could be disposed on towed implement  102 , and operator control inputs can be provided to the control system  160  on towed implement  102  through a suitable link  104 . In addition, some portions of depth control system  160  can be disposed on towing vehicle  100  while other portions of it can be on towed implement  102 . It is shown and described on towing vehicle  100  in the present description, for the sake of example only. 
     Towed implement  102  illustratively includes one or more depth or position sensors  172 , ground-engaging elements  108 , main depth control actuators  174 , stabilizer wheel depth control actuators  128 ,  130 , main wheels  112  and stabilizer wheels  120 - 122 . Towed implement  102  can include a wide variety of other towed implement functionality  176 , as well. 
     Link  104  can include a mechanical link  150 , a depth control signal communication link  152 , and it can include a wide variety of other links  154 . Mechanical link  150  can include a mechanical connection between towing vehicle  100  and towed implement  102  so that vehicle  100  can tow implement  102 . It can also include a hydraulic link, a power takeoff, or other mechanical links. 
     Depth control signal communication link  152  can include a wired or wireless connection that provides electrical signals (where the hydraulic control valves  140  are disposed on towed implement  102 ). Communication link  152  can also include a wired or wireless electrical link where the main depth control actuators and/or the stabilizer wheel depth control actuators are electrical actuators. It can include a wide variety of other links as well. 
     Before describing the overall operation of the items shown in  FIG. 3 , a brief overview of some of the components in  FIG. 3 , and their operation, will first be provided. Communication system  158  can illustratively be used to enable communication between towing vehicle  100  and towed implement  102 , or to remote systems or vehicles as well. Therefore, communication system  158  can include a controller area network (CAN) bus, a near field communication system, a cellular communication system, or a wide variety of other communication systems, or combinations of systems. 
     Operator interface mechanisms  162  are illustratively mechanisms that are provided for interaction by operator  165 . Operator  165  illustratively interacts with operator interface mechanisms  162  in order to control and manipulate towing vehicle  100 , and towed implement  102 . By way of example, operator interface mechanisms  162  can include levers, joysticks, steering wheels, pedals, mechanical linkages, user interface display devices, user actuatable display elements (such as links, icons, display buttons, etc.), a touch sensitive screen, a microphone and speech recognition system, a loud speaker, and/or other visual, audible, or haptic interface mechanisms. 
     Main depth control logic  166  illustratively receives an operator input from operator  165  setting a main depth control setting that can be used to generate control signals to control main depth control actuators  174  to set a position of main wheels  112  relative to frame  106 . This establishes a main depth at which implement  102  will engage the soil over which implement  102  is traveling. Setting identifier logic  167  can also receive the main depth setting input by operator  165  and identify a corresponding position for stabilizer wheel depth control actuators  128 ,  130 , based upon the main depth control setting. For instance, if operator  165  provides an input indicating that he or she wishes the main depth to be 4 inches, then setting identifier logic  167  illustratively identifies a corresponding position for stabilizer wheels  120 ,  122  relative to frame  106  so that implement  102  will be level, or at another desired orientation. 
     In one example, setting identifier logic  167  can access data store  161  and depth control curves  163 . Depth control curves  163  can identify the stabilizer wheel depth or position based on a main depth control setting. Setting identifier logic  167  can identify the corresponding stabilizer wheel position in other ways as well. Main depth control logic  166  illustratively uses signal generator logic  169  to generate control signals to control the main depth control actuators  174  so that they position wheels  112  relative to frame  106  to obtain the main depth setting. Stabilizer wheel depth control logic  168  illustratively uses signal generator logic  169  to generate actuator control signals  142  (shown in  FIG. 2 ) to control stabilizer wheel depth control actuators  128 ,  130  so that they set stabilizer wheels  120 ,  122  in the desired position relative to frame  106 . 
     When operator  165  changes the main depth control setting, then the process can be repeated so that setting identifier logic  167  identifies a new corresponding position for the stabilizer wheel depth control actuators  128 ,  130 , based upon the new main depth control setting. Also, it may be that operator  165  wishes to change the position of the stabilizer wheels, relative to frame  106 , without changing the main depth setting, based upon observation or for other reasons. In that case, operator  165  illustratively provides operator inputs to stabilizer wheel depth control logic  168  to individually control the stabilizer wheel depth control actuators  128 ,  130 , independently of the main depth control actuators  174 . In one example, each of the stabilizer wheel depth control actuators  128 ,  130  can also be controlled independently of the other(s). These are examples only.  FIGS. 4A and 4B  (collectively referred to herein as  FIG. 4 ) show a flow diagram illustrating one example of the operation of depth control system  160  in controlling the stabilizer wheel depth control actuators  128 ,  130  and main depth control actuators  174 . In one example, depth control system  160  first calibrates the depth sensors  172  on towed implement  102 . This is indicated by block  180  in the flow diagram of  FIG. 4 . For instance, it can run actuators  174  and  128 ,  130  to the end of their ranges of motion in one extreme position. It can then run them to the end of their ranges of motion in the other extreme position. The sensor signals can be detected at each extreme position to calibrate the sensors  172 . This is indicated by block  182 . The depth sensors can be calibrated in a wide variety of other ways as well, and this is indicated by block  184 . 
     Depth control system  160  then detects a main depth setting input setting indicative of the depth or position of the main depth control actuators  174 , to position the main weight bearing wheels  112  at a desired position relative to frame  108 . This is indicated by block  186 . The main depth setting input can be an operator input as indicated by block  181 . It can be an automated input, such as an input obtained by accessing a prescription file that prescribes a depth setting based on a location in the field. Vehicle  100  or implement  102  may include a geographic location sensor (such as a GPS receiver), and the geographic location can be used to find a prescribed depth in the prescription file. This is indicated by block  183 . The main depth setting can also be obtained based on a sensor signal from a sensor on implement  102  (or elsewhere) indicating that the main depth setting should be changed. This is indicated by block  185 . The main depth setting can be obtained in other ways as well. This is indicated by block  187 . 
     Once the main depth setting is received, setting identifier logic  167  illustratively identifies a corresponding position or depth that the stabilizer depth control actuators  128 ,  130 , should be set to, based upon the main depth setting. This is indicated by block  188 . The corresponding position or depth of the stabilizer depth control actuators is illustratively identified based upon a correlation between the main and stabilizer actuator positions. This is indicated by block  190 . In one example, logic  167  identifies the corresponding position of the stabilizer depth control actuators  128 ,  130  by accessing one or more depth control curves  163  in data store  161 . For any given main depth control setting, the depth control curves  163  illustratively output a stabilizer depth control actuator position corresponding to the main depth setting. Accessing a stored curve is indicated by block  192 . It will be noted that setting identifier logic  167  can identify the stabilizer wheel control actuator position, based upon the main depth setting, in a wide variety of other ways as well, and this is indicated by block  194 . Some of these are discussed in more detail below with respect to  FIG. 5 . 
     Main depth control logic  166  then controls the signal generator logic  169  to generate one or more main actuator control signals based upon the detected operator input. This is indicated by block  196 . For instance, if the main depth control actuators  174  are electric actuators, then the control signals may be electric signals that are provided by communication system  158  to towed implement  102  to control actuators  174 . If they are hydraulic actuators, then the control signals may illustratively control hydraulic valves (either electrically or hydraulically) to actuate the hydraulic actuators  174 . 
     Stabilizer wheel depth control logic  168  also illustratively controls signal generator logic  169  to generate stabilizer actuator control signals based upon the identified corresponding position or depth of the stabilizer wheel depth control actuators  128 ,  130 . This is indicated by block  198 . Again, when the stabilizer wheel depth control actuators  128 ,  130  are electric actuators (such as electric motors) the control signals may be electric signals. When actuators  128 ,  130  are hydraulic actuators, then the control signals are illustratively provided to control hydraulic valves to move actuators  128 ,  130  so that stabilizer wheels  120 ,  122  assume the identified position relative to frame  106 , corresponding to the main depth setting. 
     Depth sensors  172  can be provided to sense the position of actuators  174 ,  128 , and  130 , or to sense the position of the wheels  112 ,  120 ,  122  relative to frame  106  in a variety of ways. For instance, they may be rotary potentiometers, rotary Hall Effect sensors, etc. that sense the position of the mechanical linkages that movably connect wheels  112 ,  120 ,  122  to frame  106 . They can be a wide variety of other sensors as well. They illustratively detect the position of wheels  112  and stabilizer wheels  120 ,  122  relative to frame  106 . This is indicated by block  200 . The control signal generator logic  169  determines whether the wheels are at the desired positions. If not, then it continues to generate the control signals to move the corresponding actuators so that the wheels are in the desired position relative to frame  106 . This is indicated by block  202 . 
     At block  204 , if there have not been any adjustments yet to the main or stabilizer actuator position settings, then so long as the tillage operation is not finished (as indicated by block  206 ), then depth control system  160  simply continues to maintain the positions of the main depth control actuators  174  and stabilizer wheel depth control actuators  128 ,  130 . This is indicated by block  208 . When the main depth control actuators  174  and the stabilizer wheel depth control actuators  128 ,  130  have moved the corresponding wheels to the desired positions relative to frame  106 , then the system  160  illustratively maintains the actuators, in that position, until a settings change is detected. For instance, it may be that operator  165  provides another input changing either the main depth setting or the stabilizer actuator position (or depth) of the stabilizer wheels. The change to the main depth setting or the stabilizer actuator position setting can also be received automatically, from a sensor input, or in other ways, as discussed above. If this is detected, as indicated by block  204 , then it is determined whether the change is to a stabilizer actuator or a main depth control actuator. If it is to change the main depth setting (e.g., to change the position of the main depth control actuators  174 ), the processing reverts to block  188 . 
     However, if the detected input is to change the position of a stabilizer wheel (or stabilizer wheel depth control actuator  128 ,  130 ) then processing may be performed in a number of different ways. For instance, it may be that actuators  128 ,  130  are independently controllable, independently of one another and of the main control actuators  174 . If so, then stabilizer wheel depth control logic  168  uses signal generator logic  169  to generate signals to isolate the stabilizer actuators  128 ,  130  relative to one another (or relative to main depth control actuators  174 ) so they can be controlled in a desired way. This is indicated by block  210 . Stabilizer wheel depth control logic  168  then uses signal generator logic  169  to generate the control signals so that they adjust the stabilizer wheel depth control actuators  128 ,  130  so that the stabilizer wheels are positioned relative to frame  108  in a desired position, as desired by operator  165 , and based on the operator input. This is indicated by block  212  in the flow diagram of  FIG. 4  (and one example is described in more detail below with respect to  FIGS. 6 and 7 ). 
     When this happens, this means that operator  165  is changing the position of the stabilizer wheels  120 ,  122  relative to frame  108  from that which was defined by the depth control curve  163  (or otherwise defined as the stabilizer position that is correlated to the main depth setting). Therefore, in one example, correlation modification logic  171  illustratively adjusts the correlation between the main and stabilizer actuator positions based upon the user input that was used to adjust the stabilizer position at block  212 . Adjusting the correlation is indicated by block  214 . 
     By way of example, stabilizer wheel depth control logic  168  can change the control curve  163  to reflect the adjustment made by operator  165 . When that happens, stabilizer wheel depth control logic  168  can illustratively continue to control the position of the stabilizer wheel depth control actuators  128 ,  130  (and hence the position of stabilizer wheels  120 ,  122  relative to frame  106 ) based upon the modified curve. 
       FIG. 5  is a flow diagram illustrating one example of the setting identifier logic  167  in identifying a stabilizer actuator position that corresponds to the main depth setting (as indicated at block  188  in  FIG. 4 ) in more detail. In one example, it may be that operator  155  provides a change to the main depth control setting to lift the entire set of ground-engaging elements  108  of implement  102  out of the ground. This may be done for purposes of transport, for purposes of making a headland turn within a field being tilled, or for other reasons. In that case, then the position of the stabilizer wheel depth control actuators  128 ,  130  need not be changed, since their purpose is to level or otherwise reposition implement  128  while it is tilling. Therefore, in one example, stabilizer wheel depth control logic  168  is configured so that it will not change the position of the stabilizer wheel depth control actuators  128 ,  130  unless the operator is changing the main depth control setting to a position where the soil-engaging elements  108  are still engaging the soil. If the change to the main depth control setting is to lift the soil-engaging elements out of the soil, then the modification to the main depth control setting input by the operator moves the main depth control actuators  174  to a position which is outside the operating range where the stabilizer wheel depth control actuators  128 ,  130  will be utilized. Thus, in one example, stabilizer wheel depth control logic  168  first determines whether the main depth setting for the implement  102  is within an activation range for the stabilizer wheel depth control actuators  128 ,  130 . Again, this may be a determination as to whether the main depth setting is set such that the ground-engaging elements  108  are completely out of the ground. If so, the main depth setting would be out of the activation range for the stabilizer actuators  128 ,  130  (e.g., they do not need to be moved). Determining whether the main depth setting for the implement is within the activation range for the stabilizer actuators  128 ,  130  is indicated by block  220  in  FIG. 5 . If it is not, then no stabilizer actuation is to be performed (i.e., the stabilizer wheel depth control actuators  128 ,  130  need not be changed). This is indicated by block  222 . 
     However, if the main depth setting for implement  102  is within the activation range of the stabilizer wheel depth control actuators  128 ,  130  (e.g., if the main depth control setting is set so that the ground-engaging elements  108  are in engagement with the ground), then stabilizer wheel depth control logic  168  illustratively accesses an item that defines a correlation between the position of the main depth control actuators  174  and the stabilizer wheel depth control actuators  128 ,  130 . This is indicated by block  224 . In doing so, it can access the depth control curves  163 , as indicated by block  226  in the flow diagram of  FIG. 5 . Curves  163  can be predetermined based on machine configuration (e.g., factory settings), they can be set by a user during a separate “leveling” procedure or based on user inputs on-the-fly, while tilling. It can access any modified curves (that have been modified based on a user adjustment to the stabilizer wheel depth control actuators). This is indicated by block  228 . The item that defines the correlation between the position of the stabilizer wheels  120 ,  122  and the main wheels  112 , relative to frame  106 , can be a dynamic model that is a machine learned model or another model that receives, as an input the main depth setting and provides, as an output, the position of the stabilizer wheel depth control actuators  128 ,  130 . Using a dynamic model is indicated by block  230  in the flow diagram of  FIG. 5 . The correlation between the positions of the different actuators can also be identified, based on a sensor output from a sensor on the implement  102 , or elsewhere, that indicates the orientation of implement  102  (e.g., whether it is level). This is indicated by block  231 . The item defining the correlation between the position of the main depth control actuators  174  and the stabilizer wheel depth control actuators  128 ,  130  can be a wide variety of other items as well, and this is indicated by block  232 . 
     Once the item defining the correlation (e.g., the control curve  163 ) is accessed, then the corresponding stabilizer actuator position is identified (using that correlation). For instance, if the correlation is identified by a depth control curve  163 , then once the main depth control setting is known, that curve can be accessed (as described in blocks  224  and  226 ) to identify the corresponding stabilizer actuator position, as indicated by block  234  in the flow diagram of  FIG. 5 . Because depth sensors  172  illustratively provide a signal indicative of the position of the stabilizer wheel depth control actuators  128 ,  130 , then the current stabilizer actuator position is compared to the identify stabilizer actuator position to determine whether there is a difference (e.g., to determine whether the actuators  128 ,  130  need to be moved, and the direction and magnitude of that move). This determination is used by signal generator logic  169  to generate the stabilizer actuator control signals to actuate stabilizer wheel depth control actuators  128 ,  130 . Comparing the current stabilizer actuator position to the position corresponding to the main depth control setting is indicated by block  236  in the flow diagram of  FIG. 5 . The signals can then be generated and processing can continue as at block  196  in  FIG. 4  above. 
       FIG. 6  is a partial block diagram, partial hydraulic schematic diagram, of main depth control system  110  and stabilizer actuators  128 ,  130 . Main depth control system  110  illustratively includes a set of position or depth sensors  172 , along with a set of main depth control actuators  174  that are coupled to move the linkages between the main frame  106  and the main weight bearing wheels  112  (illustrated in  FIG. 1 ). 
     System  110  also illustratively includes control valve  240 . When in the position illustrated in  FIG. 6 , control valve  240  can provide hydraulic fluid under pressure to the hydraulic cylinders  174  so that the extension of those cylinders is illustratively controlled. When it is moved into the opposite position of that shown in  FIG. 6 , then this will inhibit the flow of hydraulic fluid either into or out of the hydraulic cylinders  174 , thus holding them in their current position. 
     Stabilizer wheel depth control actuators  128 ,  130  each illustratively have a corresponding control valve  140 ,  244 . The valves are illustratively independently operable to move between the positions shown in  FIG. 6  and the opposite positions. As shown in  FIG. 6 , the valve position of valves  140  and  244  inhibit the flow of hydraulic fluid into or out of actuators  128 ,  130 , thus holding them in their current position. In order to independently control actuators  128 ,  130 , stabilizer wheel depth control system  168  illustratively controls valve  240  to move it to the opposite position of that shown in  FIG. 6  so that the stabilizer actuators  128  and  130  are isolated from the main depth control actuators  174 . It then illustratively moves one of valves  140  and  244  (for the sake of the present description it will move valve  140  first) into the opposite position of that shown in  FIG. 6 . Thus, hydraulic fluid under pressure can be provided to actuator  128  to change its position independently of the other actuators shown in  FIG. 6 . 
     Once actuator  128  is in the desired position, control logic  168  can then use signal generator logic  169  to generate control signals to move valve  140  back to the position shown in  FIG. 6 , and to move valve  244  into the opposite position of that shown in  FIG. 6 . In this way, actuator  130  is isolated from the other hydraulic actuators in  FIG. 6 , and it can be independently controlled. Once it has been controlled to be in the desired position, valve  244  can again be moved to the position shown in  FIG. 6 , and valve  240  can be moved back to the position shown in  FIG. 6  as well. In this way, the main depth setting can be changed by the operator, without also changing the position of actuators  128  and  130 . 
     However, if the generator changes the main depth setting, then stabilizer wheel depth control logic  168  can automatically isolate and control actuators  128  and  130  to move them to their new corresponding positions as well. Further, operator  165  can use stabilizer wheel depth control logic  168  to generate control signals to independently control actuators  128  and  130  as well. It does so in the same was as described above, but based on an operator input. Thus, the isolation and independent control of the actuators  128  and  130  can be done either automatically by stabilizer wheel depth control logic  168 , or manually by operator  165  using a suitable operator interface mechanism  162  to control the depth control system  160  to generate the proper control signals.  FIG. 7  is similar to  FIG. 6 , and similar items are similarly numbered. However, it can be seen in  FIG. 7  that an additional valve  246  is also provided. Therefore, instead of only introducing hydraulic fluid under pressure into the base end of the various hydraulic cylinders in  FIG. 7 , valve  246  can be controlled to controllably introduce hydraulic fluid under pressure into the rod end as well. Thus, the position of stabilizer wheels  120 - 122  can be controlled from inside the operator compartment of towing vehicle  100 . Control system  160  can automatically actuate the stabilizer wheel depth control actuators  128 ,  130  corresponding to depth changes that are input from operator  165  to the main depth setting. Also, because actuators  128 ,  130  can be independently operated, the operator  165  can determine a preferred position for each of them, and that position will be automatically changed based on changes to the main depth setting input by operator  165 . In one example, the changes will only be made to the stabilizer actuators when the main depth setting is set so that the soil-engaging elements  108  are engaging the soil. If they are raised out of the soil, stabilizer control need not be performed. 
     It will also be noted that actuators  128 ,  130  can be electrical actuators or hydraulic actuators. If they are hydraulic actuators, they can be on their own hydraulic circuit or they can be isolatable, but on the same hydraulic circuit as the main depth control actuators  174 , as illustrated in  FIGS. 6 and 7 . 
     Further, it will be noted that the stabilizer wheel depth control actuators  128 ,  130  can be controlled based upon a sensed pressure (or weight carrying-force) setting. Operator  165  can set a given pressure for the actuator to hold. In that case, depth sensors  172  can be replaced or augmented with pressure sensors that sense the hydraulic cylinder pressure (or other actuator pressure) on actuators  128 ,  130 . Stabilizer wheel depth control logic  168  will then use signal generator logic  160  to generate control signals to control the stabilizer wheel depth control actuators  128 ,  130 , to maintain the desired pressure. When the main depth setting is changed, the pressure on actuators  128 ,  130  will correspondingly change so that control logic  168  can modify the position of actuators  128 ,  130 , to maintain the desired pressure. 
     The present discussion has mentioned processors and servers. In one embodiment, the processors and servers include computer processors with associated memory and timing circuitry, not separately shown. They are functional parts of the systems or devices to which they belong and are activated by, and facilitate the functionality of the other components or items in those systems. 
     Also, a number of user interface displays have been discussed. They can take a wide variety of different forms and can have a wide variety of different user actuatable input mechanisms disposed thereon. For instance, the user actuatable input mechanisms can be text boxes, check boxes, icons, links, drop-down menus, search boxes, etc. They can also be actuated in a wide variety of different ways. For instance, they can be actuated using a point and click device (such as a track ball or mouse). They can be actuated using hardware buttons, switches, a joystick or keyboard, thumb switches or thumb pads, etc. They can also be actuated using a virtual keyboard or other virtual actuators. In addition, where the screen on which they are displayed is a touch sensitive screen, they can be actuated using touch gestures. Also, where the device that displays them has speech recognition components, they can be actuated using speech commands. 
     A number of data stores have also been discussed. It will be noted they can each be broken into multiple data stores. All can be local to the systems accessing them, all can be remote, or some can be local while others are remote. All of these configurations are contemplated herein. Also, the figures show a number of blocks with functionality ascribed to each block. It will be noted that fewer blocks can be used so the functionality is performed by fewer components. Also, more blocks can be used with the functionality distributed among more components. 
       FIG. 8  is a simplified block diagram of one illustrative example of a handheld or mobile computing device that can be used as a user&#39;s or client&#39;s hand held device  16 , in which the present system (or parts of it) can be deployed. For instance, a mobile device can be deployed in the operator compartment of towing vehicle  100  for use in controlling actuators, or generating, processing, or displaying data.  FIGS. 9-10  are examples of handheld or mobile devices. 
       FIG. 8  provides a general block diagram of the components of a client device  16  that can run some components shown in  FIG. 1 , that interacts with them, or both. In the device  16 , a communications link  13  is provided that allows the handheld device to communicate with other computing devices and under some embodiments provides a channel for receiving information automatically, such as by scanning. Examples of communications link  13  include allowing communication though one or more communication protocols, such as wireless services used to provide cellular access to a network, as well as protocols that provide local wireless connections to networks. 
     In other examples, applications can be received on a removable Secure Digital (SD) card that is connected to an interface  15 . Interface  15  and communication links  13  communicate with a processor  17  (which can also embody processors from previous FIGS.) along a bus  19  that is also connected to memory  21  and input/output (I/O) components  23 , as well as clock  25  and location system  27 . 
     I/O components  23 , in one example, are provided to facilitate input and output operations. I/O components  23  for various examples of the device  16  can include input components such as buttons, touch sensors, optical sensors, microphones, touch screens, proximity sensors, accelerometers, orientation sensors and output components such as a display device, a speaker, and or a printer port. Other I/O components  23  can be used as well. 
     Clock  25  illustratively comprises a real time clock component that outputs a time and date. It can also, illustratively, provide timing functions for processor  17 . 
     Location system  27  illustratively includes a component that outputs a current geographical location of device  16 . This can include, for instance, a global positioning system (GPS) receiver, a LORAN system, a dead reckoning system, a cellular triangulation system, or other positioning system. It can also include, for example, mapping software or navigation software that generates desired maps, navigation routes and other geographic functions. 
     Memory  21  stores operating system  29 , network settings  31 , applications  33 , application configuration settings  35 , data store  37 , communication drivers  39 , and communication configuration settings  41 . Memory  21  can include all types of tangible volatile and non-volatile computer-readable memory devices. It can also include computer storage media (described below). Memory  21  stores computer readable instructions that, when executed by processor  17 , cause the processor to perform computer-implemented steps or functions according to the instructions. Processor  17  can be activated by other components to facilitate their functionality as well. 
       FIG. 9  shows one example in which device  16  is a tablet computer  600 . In  FIG. 9 , computer  600  is shown with user interface display screen  602 . Screen  602  can be a touch screen or a pen-enabled interface that receives inputs from a pen or stylus. It can also use an on-screen virtual keyboard. Of course, it might also be attached to a keyboard or other user input device through a suitable attachment mechanism, such as a wireless link or USB port, for instance. Computer  600  can also illustratively receive voice inputs as well. 
       FIG. 10  shows that the device can be a smart phone  71 . Smart phone  71  has a touch sensitive display  73  that displays icons or tiles or other user input mechanisms  75 . Mechanisms  75  can be used by a user to run applications, make calls, perform data transfer operations, etc. In general, smart phone  71  is built on a mobile operating system and offers more advanced computing capability and connectivity than a feature phone. 
     Note that other forms of the devices  16  are possible. 
       FIG. 11  is one example of a computing environment in which elements of  FIG. 3 , or parts of it, (for example) can be deployed. With reference to  FIG. 11 , an example system for implementing some embodiments includes a general-purpose computing device in the form of a computer  810 . Components of computer  810  may include, but are not limited to, a processing unit  820  (which can comprise processors or servers from previous FIGS.), a system memory  830 , and a system bus  821  that couples various system components including the system memory to the processing unit  820 . The system bus  821  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. Memory and programs described with respect to  FIG. 3  can be deployed in corresponding portions of  FIG. 11 . 
     Computer  810  typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer  810  and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media is different from, and does not include, a modulated data signal or carrier wave. It includes hardware storage media including both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer  810 . Communication media may embody computer readable instructions, data structures, program modules or other data in a transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. The system memory  830  includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM)  831  and random access memory (RAM)  832 . A basic input/output system  833  (BIOS), containing the basic routines that help to transfer information between elements within computer  810 , such as during start-up, is typically stored in ROM  831 . RAM  832  typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit  820 . By way of example, and not limitation,  FIG. 11  illustrates operating system  834 , application programs  835 , other program modules  836 , and program data  837 . 
     The computer  810  may also include other removable/non-removable volatile/nonvolatile computer storage media. By way of example only,  FIG. 11  illustrates a hard disk drive  841  that reads from or writes to non-removable, nonvolatile magnetic media, an optical disk drive  855 , and nonvolatile optical disk  856 . The hard disk drive  841  is typically connected to the system bus  821  through a non-removable memory interface such as interface  840 , and optical disk drive  855  are typically connected to the system bus  821  by a removable memory interface, such as interface  850 . Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (e.g., ASICs), Application-specific Standard Products (e.g., ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc. 
     The drives and their associated computer storage media discussed above and illustrated in  FIG. 11 , provide storage of computer readable instructions, data structures, program modules and other data for the computer  810 . In  FIG. 11 , for example, hard disk drive  841  is illustrated as storing operating system  844 , application programs  845 , other program modules  846 , and program data  847 . Note that these components can either be the same as or different from operating system  834 , application programs  835 , other program modules  836 , and program data  837 . 
     A user may enter commands and information into the computer  810  through input devices such as a keyboard  862 , a microphone  863 , and a pointing device  861 , such as a mouse, trackball or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit  820  through a user input interface  860  that is coupled to the system bus, but may be connected by other interface and bus structures. A visual display  891  or other type of display device is also connected to the system bus  821  via an interface, such as a video interface  890 . In addition to the monitor, computers may also include other peripheral output devices such as speakers  897  and printer  896 , which may be connected through an output peripheral interface  895 . 
     The computer  810  is operated in a networked environment using logical connections (such as a local area network—LAN, or wide area network WAN) to one or more remote computers, such as a remote computer  880 . 
     When used in a LAN networking environment, the computer  810  is connected to the LAN  871  through a network interface or adapter  870 . When used in a WAN networking environment, the computer  810  typically includes a modem  872  or other means for establishing communications over the WAN  873 , such as the Internet. In a networked environment, program modules may be stored in a remote memory storage device.  FIG. 11  illustrates, for example, that remote application programs  885  can reside on remote computer  880 . 
     It should also be noted that the different embodiments described herein can be combined in different ways. That is, parts of one or more embodiments can be combined with parts of one or more other embodiments. All of this is contemplated herein. 
     Example 1 is a method of controlling a towed agricultural implement, comprising:
         receiving an input indicative of a main depth setting;   automatically identifying a stabilizer setting, indicative of a position of a stabilizer wheel relative to a frame of the towed agricultural implement, corresponding to the main depth setting;   generating a main depth control signal, to control a main depth actuator that sets a position of a set of main depth control system wheels relative to the frame, based on the main depth setting; and   automatically generating a stabilizer control signal based on the identified stabilizer setting, to control a stabilizer actuator, independently of the main depth actuator, to set the position of the stabilizer wheel relative to the frame.       

     Example 2 is the method of any or all previous examples wherein identifying a stabilizer setting comprises:
         accessing a predefined correlation indicator, indicative of a predefined correlation between the position of the main depth control system wheels relative to the frame and the stabilizer wheel relative to the frame; and   identifying the stabilizer setting based on the main depth setting and the predefined correlation indicator.       

     Example 3 is the method of any or all previous examples wherein identifying the stabilizer setting comprises:
         determining whether the main depth setting is within a range of activation in which the stabilizer setting is to be set; and   if not, maintaining the stabilizer setting unchanged.       

     Example 4 is the method of any or all previous examples and further comprising:
         receiving a change input indicative of a change to the stabilizer setting; and   modifying the predefined correlation indicator based on the change to the stabilizer setting.       

     Example 5 is the method of any or all previous examples and further comprising:
         receiving a change input indicative of a change to the main depth setting;   automatically accessing the modified predefined correlation indicator; and   identifying a different stabilizer setting based on the changed main depth setting and the modified predefined correlation indicator.       

     Example 6 is the method of any or all previous examples and further comprising:
         generating the main depth control signal, to control the main depth actuator, based on the changed main depth setting; and   automatically generating the stabilizer control signal based on the identified different stabilizer setting, to control the stabilizer actuator, independently of the main depth actuator, to set the position of the stabilizer wheel relative to the frame.       

     Example 7 is the method of any or all previous examples wherein accessing the predefined correlation indicator comprises:
         accessing a predefined correlation curve that correlates the main depth setting to the stabilizer setting.       

     Example 8 is the method of any or all previous examples wherein accessing the predefined correlation indicator comprises:
         accessing a sensor input or a dynamic model that correlates the main depth setting to the stabilizer setting.       

     Example 9 is the method of any or all previous examples wherein the main depth actuator and the stabilizer actuator are hydraulic actuators, and wherein automatically generating the stabilizer control signal comprises:
         controlling a hydraulic valve to isolate the stabilizer actuator from the main depth setting actuator; and   controlling the stabilizer actuator based on the identified stabilizer setting to set the position of the stabilizer wheel relative to the frame.       

     Example 10 is the method of any or all previous examples wherein receiving an input indicative of the main depth setting comprises receiving the input as one of a position setting or a pressure setting and wherein identifying the stabilizer setting comprises identifying one of a position setting or a pressure setting. 
     Example 11 is a towed agricultural implement that travels over ground, comprising:
         a frame;   a ground engaging element coupled to the frame;   a main depth control system that receives a main depth control signal from a towing vehicle and controls a position of the ground engaging element and the frame, relative to the ground, based on the main depth control signal;   a stabilizer wheel;   a movable stabilizer link that movably couples the stabilizer wheel to the frame; and   a stabilizer actuator, that is controllable independently of the main depth control system, that receives a stabilizer position control signal from the towing vehicle and moves the stabilizer link relative to the frame to change a position of the stabilizer wheel relative to the frame based on the stabilizer position control signal.       

     Example 12 is the towed agricultural vehicle of any or all previous examples and further comprising:
         a position sensor configured to sense a sensed value indicative of a position of the stabilizer wheel relative to the frame and to generate a position signal indicative of the sensed value.       

     Example 13 is the towed agricultural vehicle of any or all previous examples wherein the stabilizer actuator comprises:
         a stabilizer hydraulic cylinder; and   a control valve controlled by the stabilizer position control signal and configured to control flow of hydraulic fluid between the hydraulic cylinder and a hydraulic system.       

     Example 14 is the towed agricultural vehicle of any or all previous examples wherein the main depth control system comprises a main depth control hydraulic actuator, and further comprising:
         an isolation valve that is controllable to isolate the stabilizer hydraulic cylinder from the main depth control hydraulic actuator so the stabilizer hydraulic cylinder is controllable independently relative to the main depth control hydraulic actuator.       

     Example 15 is the towed agricultural vehicle of any or all previous examples wherein the stabilizer actuator comprises:
         an electric actuator.       

     Example 16 is a depth control system for controlling a towed agricultural implement, the depth control system comprising:
         an interface mechanism receiving an input indicative of a main depth setting;   setting identifier logic that automatically identifies a stabilizer setting, indicative of a position of a stabilizer wheel relative to a frame of the towed agricultural implement, corresponding to the main depth setting;   signal generator logic;   main depth control logic that controls the signal generator logic to generate a main depth control signal, to control a main depth actuator that sets a position of a set of main depth control system wheels relative to the frame, based on the main depth setting; and   stabilizer wheel depth control logic that controls the signal generator logic to automatically generate a stabilizer control signal based on the identified stabilizer setting, to control a stabilizer actuator, independently of the main depth actuator, to set the position of the stabilizer wheel relative to the frame.       

     Example 17 is the depth control system of any or all previous examples wherein the setting identifier logic is configured to access a predefined correlation indicator, indicative of a predefined correlation between the position of the main depth control system wheels relative to the frame and the stabilizer wheel relative to the frame, and identify the stabilizer setting based on the main depth setting and the predefined correlation indicator. 
     Example 18 is the depth control system of any or all previous examples wherein the setting identifier logic is configured to identify the stabilizer setting by determining whether the main depth setting is within a range of activation in which the stabilizer setting is to be set, and if not, maintaining the stabilizer setting unchanged. 
     Example 19 is the depth control system of any or all previous examples wherein the input mechanism is configured to receive a change input indicative of a change to the stabilizer setting, and further comprising:
         correlation modification logic configured to modify the predefined correlation indicator based on the change to the stabilizer setting.       

     Example 20 is the depth control system of any or all previous examples wherein the main depth actuator and the stabilizer actuator are hydraulic actuators, and wherein the stabilizer wheel depth control logic is configured to automatically generate the stabilizer control signal by controlling a hydraulic valve to isolate the stabilizer actuator from the main depth setting actuator, and controlling the stabilizer actuator based on the identified stabilizer setting to set the position of the stabilizer wheel relative to the frame. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.