Abstract:
Provided is an apparatus and method for controlling seed population for a conventional row crop planter utilizing a microprocessor, information from a seed population controller provided with the conventional row crop planter, a GPS or other locating or positioning device and motors for driving the conventional seed metering system of the planter. The microprocessor further feedback from the motors and compares the actual seed population data with the desired density and adjusts the output of the motors to compensate for variations in seed population densities.

Description:
FIELD OF THE INVENTION 
       [0001]    1. Background of the Invention 
         [0002]    The present disclosed technology relates generally to agricultural seeding machines, and in particular an apparatus and method for controlling the seed population during the planting process. 
         [0003]    2. Description of the Related Art 
         [0004]    In the agricultural industry, a class of crops designated as row crops, meaning those crops planted in furrows, are planted utilizing a seed planter. The seed planter may utilize a number of seed planning row units attached to a tool bar of the planter. The individual seed row units are evenly spaced along the tool bar so that seeds are planted in rows at a specified distance apart. 
         [0005]    Each seed row unit has a hopper in which the seeds are placed. A metering disk regulates the seeds dropping from the hopper into a seed tube that guides the seed into the ground. Various systems may be employed to facilitate the dropping of the seed into the seed tube. Some systems utilize gravity to direct the seeds whereas others may utilize a vacuum system. 
         [0006]    The metering disk utilizes holes or cavities that accept the seed, typically one seed per hole or cavity, from the seed hopper. As the metering disk rotates, the individual seed drops into the seed tube. A sprocket and chain drive may be employed to rotate the seed disk, or the hydraulics system of the tractor may also be used. The metering disk provides for a range of settings for controlling the spacing of seeds, and the rate in which the seeds are placed in the seed tube. The ability to control seed population is vital for farming operations. If the seeds are planted too close together, the quality of crops may be affected. Conversely, if the seeds are planted too far apart, the number of bushels per acre is reduced. The rate at which the seeds are planted affect the seed population over a given area and is commonly call a seed population density. 
         [0007]    The rate the seeds are planted can be affected by wear and/or limitations of the planter. In mechanical chain driven systems, as the associated drivetrain becomes worn, there is a tendency for the lag in the system that results in uneven seed spacing or a change of the seed population per row. This may also occur when the hydraulics system experiences a leak or a drop in pressure. Likewise, the terrain may also affect the seed population density. GPS systems are often used to determine the location of the tractor and may be utilized to program the seed population for a given area of the field. 
         [0008]    Therefore, there is a need for a system and method to accurately control seed population for both hydraulically and mechanically-driven seed row units that provides accurate seed placement and provides for alternative seed population densities over a specific area of the field. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides an apparatus and method for controlling seed population for a conventional row crop planter that does not suffer from the problems and limitation of prior art seed metering systems as set forth above. 
         [0010]    One embodiment of the present invention utilizes a power unit to control the rate of rotation of the metering disk. A sensor monitors the rotational speed of the metering disk and provides an input into a controller. The controller also receives a signal from the original seed planter population control unit, which provides an output based upon the translation seed of the planter. The controller compares the output of the original seed population control unit with the output provided by the sensor monitoring the speed of the metering disk. The controller processes a feedback loop and provides an output in the form of electrical current to power the power unit that rotates the metering disk. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The drawings constitute a part of this specification and include exemplary embodiments of the disclosed subject matter illustrating various objects and features thereof, wherein like references are generally numbered alike in the several views. 
           [0012]      FIG. 1  is a partial sectional side elevational view of a conventional seed row planter. 
           [0013]      FIG. 2  is an isometric view of an improved seed metering assembly embodying principles of the disclosed subject matter. 
           [0014]      FIG. 3  is a block diagram of the seed population system. 
           [0015]      FIG. 4A-4B  are circuit diagrams of the seed population system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    As required, detailed aspects of the disclosed subject matter are disclosed herein; however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure. 
         [0017]    Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, up, down, front, back, right and left refer to the invention as orientated in the view being referred to. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Forwardly and rearwardly are generally in reference to the direction of travel, if appropriate. This terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning. 
         [0018]    Referring to the drawings,  FIG. 1  illustrates a partial sectional side elevational view of a seed planter row unit  10  of a vacuum planter having a conventional seed metering system  15 . The row unit  10  is shown mounted to a tool bar  12 . The tool bar  12  allows for the mounting of a plurality of seed row units. The tool bar  12  is part of a implement (not shown) that is pulled behind a vehicle (not shown). The implement has wheels that contact the ground and support the implement, and a power takeoff shaft (not shown) for powering the seed planter  10 . The vehicle may include, but is not limited to a tractor. 
         [0019]    The conventional seed metering system  15  includes a seed metering unit  16  operably connected to a transmission assembly  28 . The transmission assembly  28  transfers rotational energy from a mechanical drive shaft  26  to the seed metering assembly  22  via a series of chains  34 ,  38 , and sprockets  30 ,  32 , and  36 . The drive shaft  26  is mounted in parallel with the tool bar  12  and rotated by either the power takeoff, or ground drive from rotation of the implement wheels. The transmission assembly  28  includes a drive sprocket  30  that is mounted on the drive shaft  26 . The drive sprocket  30  drives a driven sprocket  32  by the engagement of a chain  34  with an idler sprocket  36 . The idler sprocket  36  maintains the tension of the chain  34 . The driven chain  38  is driven by the drive sprocket  32 , and drives the metering sprocket  27  at the seed metering unit  16 . 
         [0020]    A seed hopper  14  is provided for storing seeds for sowing by the individual seed planter row units  10 . A seed metering unit  16  is operably connected with the seed hopper  14  for controlling transfer of the seed from the row unit  10  to the seed tube  24 . To control the depth of the furrow, a pair of depth gauge wheels are positioned at both sides of the seed planter row unit  10  including an outboard depth gauge wheel  18 . A furrow wheel  20  is positioned behind seed planter row unit  10  for closing the furrow and covering the seed with soil. The seed metering unit  16  is positioned below the seed hopper  14 , and controls the rate of release of seeds from the seed hopper  14  into the seed tube  24  by a seed plate (not shown). 
         [0021]    A shaft  23  extending between the interior and exterior of the seed metering unit  16  mounts the seed plate within the seed metering assembly  22 , and mounts the metering sprocket  27  at the exterior of the seed metering unit  16 . To change the sowing distance between seeds, a variety of sprockets with different numbers of teeth may be used for the drive sprocket  30  and the driven sprocket  32 . As seen in  FIG. 1 , the seed metering assembly  22  is controlled by the rotation of the drive shaft  26 . The drive shaft  26  is operationally connected to a rate controller on the vehicle. Therefore, the translational speed of the vehicle effectively controls the speed in which the seed metering assembly  22  releases seeds into the seed tube  24 . High translational speed of the vehicle, or traversing rough or rocky terrain, may cause the drive shaft  26  to spin erratically thereby affecting the seed population. Furthermore, due to the fact that seed spacing is dependent upon the rotational speed of the seed metering disk, to achieve lighter seed populations the translational speed of the vehicle must also be very slow which is often difficult to consistently maintain while planting. 
         [0022]    Referring to  FIG. 2 , an improved seed metering system  40  for a seed planter row unit  46  is shown, and includes a seed metering unit  41  operably connected to a seeding control assembly  43 . The seed planter row unit  46  shown in  FIG. 2  is used with a vacuum planter, however the seeding control assembly  43  may be used with non-vacuum planter units. The seeding control assembly  43  replaces the traditional transmission assembly  28  of the traditional seed planter row unit  10  shown in  FIG. 1 . The seeding control assembly  43  includes an electric motor  44  operably connected with the seed plate (not shown) to more efficiently and accurately control the rate of release of seeds from the seed hopper  14 . In an embodiment, a shaft  47  extending between the interior of the seed metering unit  41  and the exterior of the seed metering unit  41  connects the seed plate with a metering sprocket (not shown) located on the exterior of the seed metering unit  41 . The electric motor  44  drives the seed plate by rotating a drive sprocket  50  mounted to a drive shaft  48 . The drive sprocket  50  engages the metering sprocket via a chain  52 . In an alternative embodiment, the chain and sprockets are not used and the drive shaft  48  is directly connected to the seed plate. 
         [0023]    The seeding control assembly  43  further comprises a seed population control unit  60  operably connected to the electric motor  44 , a sensor  56 , the vehicle, and the rate controller of the vehicle. 
         [0024]    The sensor  54  monitors the rotational speed of the drive shaft  48 . In an embodiment the sensor  54  is a Hall-Effect sensor. The output of the sensor  54  is sent by a wire  56  to the seeding population control unit  60 . The seed population control unit  60  receives a speed signal from the vehicle corresponding to the translational speed of the vehicle, and a seed population rate signal from the rate controller on the vehicle. 
         [0025]    A block diagram of the seed population control unit  60  of improved seeding control assembly  43  is shown in  FIG. 3 . The seed population control unit  60  receives an input signal  58  in the form of the pulse width modulation from the original equipment manufacturer (OEM) seed population controller. The tractor or OEM seed population controller may also utilize global positioning system (GPS) information as well as ground speed radar the output signal or alternatively, provide an input signal  59  to the seed population control unit  60 . Further, seed population control unit  60  receives an input signal  62 , also in the form of pulse width modulation, from the sensor  54  that is measuring the revolutions per minute (RPM) of the drive shaft  48  driven by the electric motor  44 . The seed population control unit  60  compares the signals from the sensor  54  with the output from the OEM seed population controller  62  to determine the effective seed population. To ensure the correct planted seed population, the seed population control unit  60  is operably connected to the electric motor  44  by a wire  45  and provides two-way communication. Seed population control unit  60  receives an RPM feedback signals  64 ,  66 ,  68 ,  70  from the electric motor  44  adapted to the individual seed planter row units  10 . An embodiment of seed population control unit  60  controls a pair of twin row planting units. An electric motor is associated with each seed metering system of the twin row planting units and provides RPM feedback signals  64 ,  65 ,  66  and  67  as illustrated in  FIG. 3 . 
         [0026]    Outputs of the seed population control unit  60  are used to power and control the electric motors associated with each individual seed metering system. The resulting output signals from the seed population control unit  60  more accurately controls the planted seed population by compensating for varying translational speed signals received from the vehicle, and eliminates multiple components which may become worn and result in uneven seed spacing. Likewise, seed population control unit  60 . Each seed planter row unit  54  receives an input signal from seed population control unit  60  as shown in  FIG. 3  to control the electric motor  44  associated with the first row unit  72 , second row  74 , third row unit  76 , and forth row unit  78 . An embodiment that utilizes a twin row planter, utilizes an electric motors on each of the seed metering system and also replaces the mechanical linkage that controls the alternating action of the seed placement that prevents the placement of two seeds next to each other in the pair of rows. Returning to  FIG. 3 , seed population control unit  60  provides output signals  72  and  73  to the electric motors on one twin row planter assembly and output signals  74  and  75  to the electric motors on another pair of twin row planter assembly. Seed population control unit  60  compares the feedback signals from each motor in the pair,  64  and  65  to alternate the placement of seeds in the rows of the twin row planter assembly. 
         [0027]    A schematic of the electrical circuitry of the seed population control unit  60  is shown in  FIG. 4A and 4B  and the schematic is described in the terms of the major components that are used to integrate the electronics of OEM and aftermarket seed metering units, GPS and similar controllers. These components are combined with the electric motors as described above to drive conventionally driven mechanical seed metering units. One embodiment of the seed population control unit  60  contains the electronics to control two, twin row planting units. The seed population control unit  60  utilizes a microprocessor  80  to receive the input signals from the rate controller, vehicle, and sensor  54  on each seed planter row unit  46  for controlling the seeding population of each row unit  46 . 
         [0028]    An embodiment utilized the  44  pin, enhanced flash, high-performance pulse width modulation and high speed analog to digital converter microcontroller such as PIC18F4431 by Microchip Technology, Inc. Microprocessor  80  receive inputs from each electric motor that drives the seed metering unit of the seed planter row unit. A Hall-Effect sensor is utilized to measure the revolutions per minute of each electric motor that controls the seed metering unit. Each speed RPM signal is received by a quad bilateral switch IC  82  such as 74HC4066 quad bilateral switch IC manufactured by Texas Instruments, Fairchild or others IC manufacturers. Quad bilateral switch IC  82  is utilized by microprocessor  80  to measure the speed of each electric motor using one input channel of microprocessor  80  that utilizes an oscillator  84  to internally control the switching (on/off) and reading of the output from quad bilateral switch IC  82  such as a PBRC20.00HR. 
         [0029]    Microprocessor  80  also receives an input from the GPS or other locating device signal of the tractor such as a GPS from the OEM tractor manufacturer or as an after-market added device such as those manufactured by Garmin or cellular GPS locators commonly available by cellular service providers. A jumper  86  is used to accommodate either a high or low signal from GPS or other locating device and a high-voltage, high-current Darlington transistor array  88  is also used as a relay driver. Microprocessor  80 , as programmed, utilizes the pulse width modulation signal from the GPS to control the electric motors for delivering the desired seed population. A series of gate and MOSFET  90  is used in combination as the low side drivers to microprocessor  80  for each electric motor. 
         [0030]    It will be appreciated that the components of the seed metering system  40  can be used for various other applications. Moreover, the seed metering system  40  can be fabricated in various sizes and from a wide range of suitable materials, using various manufacturing and fabrication techniques. 
         [0031]    It is to be understood that while certain aspects of the disclosed subject matter have been shown and described, the disclosed subject matter is not limited thereto and encompasses various other embodiments and aspects.