Abstract:
Systems, methods and apparatus are provided for controlling an agricultural implement having a plurality of row units. In some embodiments, seeds are planted by rotating a seed disc in a first direction; seeds are then unloaded from a seed disc into a seed pool by rotating the seed disc in a second direction. In some such embodiments an amount of rotation in the second rotation is selected to ensure that seeds are released into the seed pool and not released from the from the seed meter.

Description:
BACKGROUND 
     Increased seed costs and increased awareness among farmers of the agronomic costs of poor seed placement have driven the development of systems for improving seed placement. Systems and apparatus have been developed for stopping seed meters at a desired location using clutches to stop a hydraulically-driven shaft from driving a seed meter, or in the case of electrically driven seed meters, using a signal to command the associated electric motor to stop. However, such systems and apparatus still allow seeds to be dropped from the seed meter in undesired locations after the motor or shaft is stopped. Thus there is a need in the art for systems, methods and apparatus of stopping a seed meter without dropping unwanted seeds from the meter; e.g., unloading a seed meter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of an embodiment of an agricultural planter. 
         FIG. 2  is a side elevation view of an embodiment of a planter row unit. 
         FIG. 3  schematically illustrates an embodiment of a planter monitoring and control system. 
         FIG. 4  is a perspective view of an embodiment of a seed meter and an embodiment of a seed meter drive. 
         FIG. 5  is a perspective view of the seed meter of  FIG. 4  with a cover removed and the seed meter drive of  FIG. 4  with a cover removed. 
         FIG. 6  is a side elevation view of the seed meter of  FIG. 4  in operation with a cover removed. 
         FIG. 7  illustrates a process for unloading a seed meter. 
         FIG. 8  illustrates a process for identifying a seed meter unload condition. 
     
    
    
     DESCRIPTION 
     Planter Monitoring and Control System 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  illustrates a tractor  5  drawing an agricultural implement, e.g., a planter  10 , comprising a toolbar  14  operatively supporting multiple row units  200 . An implement monitor  50  preferably including a central processing unit (“CPU”), memory and graphical user interface (“GUI”) (e.g., a touch-screen interface) is preferably located in the cab of the tractor  10 . A global positioning system (“GPS”) receiver  52  is preferably mounted to the tractor  10 . 
     Turing to  FIG. 2 , an embodiment is illustrated in which the row unit  200  is a planter row unit. The row unit  200  is preferably pivotally connected to the toolbar  14  by a parallel linkage  216 . An actuator  218  is preferably disposed to apply lift and/or downforce on the row unit  200 . An opening system  240  preferably includes two opening discs  244  rollingly mounted to a downwardly-extending shank  254  and disposed to open a v-shaped trench  38  in the soil  40 . A pair of gauge wheels  248  is pivotally supported by a pair of corresponding gauge wheel arms  260 ; the height of the gauge wheels  248  relative to the opener discs  244  sets the depth of the trench  38 . A depth adjustment rocker  268  limits the upward travel of the gauge wheel arms  260  and thus the upward travel of the gauge wheels  248 . 
     Continuing to refer to  FIG. 2 , a seed meter  230  such as that disclosed in Applicant&#39;s co-pending International Patent Application No. PCT/US2012/030192, the disclosure of which is hereby incorporated herein by reference, is preferably disposed to deposit seeds  42  from a hopper  226  into the trench  38 , e.g., through a seed tube  250  disposed to guide the seeds toward the trench. The seed meter  230  is preferably driven by an electric drive  310  configured to drive a seed disc within the seed meter. A seed sensor  305  (e.g., an optical or electromagnetic seed sensor configured to generate a signal indicating passage of a seed) is preferably mounted to the seed tube  250  and disposed to send light or electromagnetic waves across the path of seeds  42 . A closing system  280  including one or more closing wheels is pivotally coupled to the row unit  200  and configured to close the trench  38 . 
     Turning to  FIG. 3 , a planter monitoring and control system  300  is schematically illustrated. The monitor  50  is preferably in electrical communication with components associated with each row unit  200  including the drives  310 , and the seed sensors  305 . The monitor  50  is preferably in electrical communication with at least one vacuum sensor  340  and the GPS receiver  52 . The vacuum sensor  340  is preferably a transducer configured to generate a signal related to a pressure associated with one or more seed meters  230 . In one embodiment, the vacuum sensor  340  is disposed to measure a pressure (i.e., vacuum level) in a pneumatic line supplying vacuum to one of the seed meters  230 . In another embodiment, the vacuum sensor  340  is disposed to measure a pressure inside one of the seed meters  230 . The monitor  50  is preferably in electrical communication with a vacuum switch  345 ; the vacuum switch is preferably configured to selectively activate or deactivate a vacuum impeller in fluid communication with the seed meters  230  for pulling a vacuum in the seed meters. 
     Continuing to refer to  FIG. 3 , in embodiments in which the row unit  200  includes a seed conveyor, the monitor  50  is preferably in electrical communication with a seed conveyor drive  315  configured to drive the seed conveyor. The seed conveyor is preferably configured to convey seeds from the meter  230  to the trench  38 ; the seed conveyor is preferably one of the embodiments disclosed in Applicant&#39;s co-pending PCT/US2012/057327, the entire disclosure of which is hereby incorporated herein by reference. 
     Continuing to refer to  FIG. 3 , the monitor  50  is preferably in electrical communication with a cellular modem  330  or other component configured to place the monitor  50  in data communication with the Internet, indicated by reference numeral  335 . Via the Internet connection, the monitor  50  is preferably enabled to receive planting prescriptions and other data. 
     In  FIG. 3 , two row units  200 - 1 ,  200 - 2  are illustrated with associated components labeled with like suffixes. It should be appreciated that the planter  10  may include a larger plurality of row units, e.g.,  16  or  48  row units. 
     Turning to  FIG. 6 , the seed meter  230  is shown in operation with the cover  232  removed for illustrative purposes. In operation, a seed disc  234  rotates along the direction indicated by an arrow A. A vacuum imposed on one side of the seed disc  234  (opposite the side shown in  FIG. 6 ) creates a vacuum differential on seed apertures  235  formed in the seed disc such that seeds  42  become entrained on the apertures. Thus the seed disc  234  rotates past a seed pool  43  at approximately the 6 o&#39;clock position and carries entrained seeds  42  along a seed path defined by the seed apertures  235 . A portion of the seed path is preferably adjacent to a singulator  237  configured to strip all but one seed from each seed aperture. The vacuum is preferably substantially cut off at a seed release location, e.g., where the seed path intersects a plane Pc. Thus as seeds  42  reach the plane Pc they are released from the disc and fall from the meter into the seed tube  250 . A brush  238  is preferably mounted to the cover  232 . The brush  238  is preferably disposed to contact the seed disc  234  along its length and brush debris from the seed disc as the seed disc rotates. The brush  238  is preferably disposed to retain seeds  42  in the seed pool  43  such that the seeds do not fall directly out of the meter without being carried out by the seed apertures  235  as described above. 
     Referring to  FIGS. 4 and 5 , the drive  310  comprises an electrical assembly  311  shielded by a cover  312  and a gearbox  313  shielded by a cover  314 . The electrical assembly  311  is in electrical communication with a motor  315  (e.g., a 12 volt electric motor) and configured to control an operating speed of the motor  315 . The motor  315  drives an input gear (not shown) of the gearbox  313 . The drive  310  is mounted to the seed meter  230 . The seed meter is preferably of the type disclosed in Applicant&#39;s co-pending international patent applications no. PCT/US2012/030192 and PCT/US2013/051971, the disclosures of which are hereby incorporated herein in their entirety by reference. Specifically, the drive module  310  is mounted to a cover  232  shielding the seed disc  234  housed within the meter  230 . The gearbox  313  includes an output gear  316  adapted to drive the seed disc  234  by sequential engagement with gear teeth  236  arranged circumferentially around a perimeter of the seed disc  234 . 
     Meter Unloading Methods 
     Turning to  FIG. 7 , a process  700  for unloading seeds from a seed disc  230  is illustrated. At step  705 , the monitor  50  preferably commands the vacuum switch  345  to activate the vacuum impeller such that the seed meters  230  impose a vacuum across the seed apertures  235 . At step  710 , the monitor  50  preferably commands the drives  310  to rotate the seed discs  234  in a first direction, thus loading seeds  42  on the seed discs. Referring to  FIG. 6 , the first direction is preferably in the direction of the arrow A, i.e., such that one of the seed apertures  235  moves from the seed pool  43  to the plane Pc before passing the brush  238 . After step  710  the operator may carry out planting operations. At step  715  the monitor  50  preferably identifies one or more seed unload conditions; in a preferred embodiment, the seed unload conditions are one of the seed unload conditions identified using a process  800  illustrated in  FIG. 8  and described later herein. Once a seed disc unload condition has been identified at step  720 , the monitor  50  preferably commands the drives  310  to rotate in a second direction opposite the first direction. On the view of  FIG. 6 , the second direction is preferably opposite the direction of the arrow A. At step  725 , the monitor  50  preferably determines whether an unloading rotation threshold has been met. The threshold may comprise a rotation of the seed disc  232 , a rotation of the drive  310 , or a time of rotation (preferably at a specified or minimum rotational rate) of the drive or seed disc. Once the threshold has been met at step  725 , the monitor preferably commands the motor to stop driving the seed discs at step  730 . 
     The threshold applied at step  725  is preferably selected such that seeds  42  will not be released from the meter upon reduction of vacuum in the seed meter  230 . For example, referring to  FIG. 6 , seeds  42  along the seed path between a plane Pv and the plane Pc will be released from the meter  230  when the seeds are released from the seed disc  232  (e.g., by loss of vacuum). The plane Pv intersects the seed path at a location vertically above an upper end of the brush  238  (i.e., such that a vertical plane intersects both the upper end of the brush and the intersection of the plane Pv and the seed path) such that seeds  42  released counterclockwise (on the view of  FIG. 6 ) of the plane Pv and clockwise of a lower portion of the brush will be retained in the meter  230  upon being released from the seed disc  232 . Thus the threshold applied at step  725  preferably corresponds to a seed disc rotation of at least an angle B ( FIG. 6 ) sufficient to rotate a seed aperture  235  from the plane Pc to the plane Pv. The angle B may be approximately 45 degrees. The threshold applied at step  725  preferably corresponds to a seed disc rotation greater than the angle B, e.g., a quarter-rotation, half rotation, full rotation, or two full rotations of the seed disc  232 . 
     The process  700  may be carried out with respect to individual meters or a plurality of meters. In one embodiment, if a seed disc unload condition is identified as to a single meter at step  715 , steps  720 ,  725 ,  730  are carried out as to that single meter. In a second embodiment, if a seed disc unload condition is identified as to a single meter at step  715 , steps  720 ,  725 ,  730  are carried out as to all of the meters on the planter  10 . In either embodiment, steps  720 ,  725 ,  730  are preferably carried out on a meter-by-meter basis; that is, the monitor  50  carries out step  725  using a motor encoder signal from a given drive  310  in order to determine whether the threshold has been met for that drive, and stops that drive at step  730  when the threshold has been met for that drive. Thus it should be appreciated that the drives  310  associated with various row units may not stop simultaneously. 
     Turning to  FIG. 8 , a preferred process  800  for identifying a seed disc unload condition is illustrated. At step  805 , the monitor  50  preferably determines whether any of the drives  310  are currently being commanded to plant (e.g., drive the seed discs at a non-zero rate). 
     If no drives  310  are being commanded to plant, at step  810  the monitor  50  preferably determines whether a command to shut off the vacuum impeller has been entered to the monitor by the operator. If so, then at step  815 , the monitor  50  preferably identifies an unload condition (e.g., determines that an unload condition has been met such that step  715  and subsequent steps of process  700  are carried out). At step  817 , the monitor  50  waits for the unload process to complete for all the seed meters on the planter, and then subsequently at step  819  commands the vacuum switch  345  to turn off the vacuum impeller. 
     If no command has been entered to shut off the vacuum impeller, then at step  820  the monitor  50  preferably determines whether any of the signals generated by the vacuum sensors  340  are below a minimum threshold. A low pass filter is preferably applied to the vacuum sensor signals, or another suitable filter is applied such that very brief variations in the signal are ignored in performing step  820 . The minimum threshold applied preferably corresponds to a vacuum pressure of between 9.5 and 11 inches of water and preferably about 10 inches of water. If any filtered vacuum sensor signal is below the minimum threshold, then at step  825  the monitor  50  preferably identifies an unload condition. 
     If no filtered vacuum sensor signal is below the minimum threshold, then at step  830  the monitor preferably determines whether any seed conveyor drive  315  has been commanded to turn off. If so, then at step  835  the monitor  50  preferably identifies an unload condition, at step  837  waits for one of the seed meters, and then subsequently at step  839  turns off the seed conveyor drive  315  associated with that meter. Steps  837 ,  839  are preferably repeated for each associated pair of seed meters  230  and seed conveyor drives  315 . It should be appreciated that a seed meter and seed conveyor are associated if they are part of the same row unit, i.e., such that the meter is supplying seed to the seed conveyor. 
     The foregoing description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment of the apparatus, and the general principles and features of the system and methods described herein will be readily apparent to those of skill in the art. Thus, the present invention is not to be limited to the embodiments of the apparatus, system and methods described above and illustrated in the drawing figures, but is to be accorded the widest scope consistent with the spirit and scope of the appended claims.