Abstract:
A fault tolerant operating method for a cotton compactor of a cotton module builder or packager of a cotton harvesting machine, which serves as an alternative to shutting down the compacting process or erratic operation thereof, in the event of indication of a fault or failure condition involving one or more sensors associated with the compactor, or a conductive path in connection with a sensor, all generally identified as a fault or failure condition.

Description:
TECHNICAL FIELD 
   This invention relates generally to control of a process for compacting and building a cotton module within a cotton packager or module builder, and more particularly, to control of a cotton module building process when one or more devices used in the process, such as a sensor, switch, or the like, is faulty, apparently faulty, or otherwise in a failure mode. 
   BACKGROUND ART 
   With a cotton module builder or packager on a cotton harvesting machine, parameters of the module building or packaging process, such as, but not limited to, the distribution of cotton within the module building chamber, the number of packing positions, and the number of compacting strokes, are all critical factors in forming a good rectangular module of compacted cotton that can be unloaded onto the ground as a stand alone module of cotton, and subsequently handled for transportation to the gin for processing. Steps of such module building or packaging processes are typically performed while harvesting cotton. As a result, it is preferred that such steps be conducted automatically, without requiring operator input or attention. If operation of the packager must be stopped, for instance, as a result of a fault or failure condition involving one or more sensors of the packager, or the compactor operates erratically, the harvesting operation will likely have to be stopped, resulting in costly downtime. 
   As is known, the distribution of the cotton within the module chamber is typically accomplished using augers attached to a compactor frame of a compactor movable upwardly and downwardly in the chamber. As cotton is being harvested and conveyed into the chamber, the augers are operated in a forward and/or a reverse direction for distributing the cotton in the chamber under the compactor. At times, the compactor is stroked or moved downwardly against the collected cotton, to compact it in the bottom of the chamber. A number of compacting positions are used to index or move the location of the compactor up within the chamber as the module is built from the bottom up. This ensures that there is space under the compactor in which to distribute the cotton. 
   The length of time that the augers run in the different directions, the number of compacting positions, and the number of compaction strokes before moving or indexing the compactor to the next position, are typically determined dependent upon input values for an electronic compaction program run by the compactor controller, these values being determined based on factors that typically include time, auger pressure, compactor pressure, level and distribution of cotton within the chamber, and the amount of cotton entering the chamber. The amount of cotton entering the chamber can vary as a result, for instance, of yield conditions, which, can vary even over a single cotton field. The amount of time the augers run forward and the amount of time they run rearward, the number of compactor positions and compacting strokes will usually be different for the different yield conditions, as well as other conditions, and will influence the distribution of cotton within the chamber. 
   The determinations by the compactor controller of the necessary duration and directions of auger operation, and whether movement to a new indexing position is necessary, are preferably automatically made, at least in part, based upon information as to the existing overall level and distribution of cotton within the chamber. This information is gathered from sensors, typically including compactor position sensors, a compactor pressure sensor, and auger pressure sensors. The compactor is preferably pivotable, and typically, two compactor position sensors are used, one for determining a position or height near a forward end of the compactor, and one near the rear end. Tilt is typically determined as a function of differences between the sensed positions, and is indicative of a higher level of cotton in the chamber adjacent to one end thereof. One or more compactor pressure sensors can be used to determine the extent to which the cotton is being compacted during the compacting strokes. One or more auger pressure sensors can be used for determining if cotton is accumulated to a greater extent toward one end of the chamber to thereby indicate need for reversal of auger direction, and for determining when compaction or indexing the compactor position is required. 
   As a result, in the event of a failure or faulty output or operation of one or more of the sensors, including of a conductive path connecting the sensor to the compactor controller for carrying sensor outputs to the controller, the information set for determining the next step of the compacting process will be incomplete. This can occur continuously, or in an erratic manner. In response, the controller can automatically shut down, or be shut down by the operator, but this will result in lost productivity as noted above, and is thus undesirable. 
   Thus, what is sought is an alternative to shut down of the compacting process when one or more sensor outputs is faulty or indicative of failure of the sensor or conductive path connecting the sensor to the controller. 
   SUMMARY OF THE INVENTION 
   What is disclosed is a fault tolerant operating method for a cotton compactor of a cotton module builder or packager of a cotton harvesting machine, which serves as an alternative to shutting down the compacting process or erratic operation thereof, in the event of indication of a fault or failure condition involving one or more sensors associated with the compactor, or a conductive path in connection with a sensor, all generally identified as a fault or failure condition. 
   According to a preferred aspect of the invention, a compactor controller is programmed to control the compactor, and is operable in several fault tolerant modes depending on the status of the sensor signals, including in a first fault tolerant mode if one or both compactor position sensors is faulty, a second fault tolerance mode in the event the compactor pressure sensor is faulty, and a third fault tolerance mode for a faulty auger pressure sensor. 
   According to one preferred method of operation, the compactor controller is operable for: 
   determining a first compactor position sensor value as a function of an output of a first compactor position sensor; 
   determining a second compactor position sensor value as a function of an output of a second compactor position sensor; 
   determining if the first compactor position sensor value is indicative of a failure condition, and, if yes, then setting the first compactor position sensor value equal to the second compactor position sensor value; 
   determining if the second compactor position sensor value is indicative of a failure condition, and, if yes, then setting the second compactor position sensor value equal to the first compactor position sensor value; 
   setting a compactor position value as:
         a value which is a function of a sum of the first and second compactor position sensor values if neither or only one of the first and second position sensor values is indicative of the failure condition, or   a default value if both of the first and second position sensor values are indicative of the failure condition; and       

   setting a compactor tilt value as:
         a value which is a function of a difference between the first and second compactor position sensor values if neither or only one of the first and second position sensor values is indicative of the failure condition, or   a default value if both of the first and second position sensor values are indicative of the failure condition.       

   As a result, in the event of a fault or failure of one or both of the compactor position sensors, or of a conductive path connecting the sensor to the compactor controller, the compactor is still able to operate in an effective manner. The augers can be operated in default directions, and the compactor can operate in a timed loop. 
   According to another preferred aspect of the invention, the compactor pressure sensor is operable to sense pressure as the compactor compacts the cotton in the bottom of the chamber. During normal operation, the controller will raise the compactor if the compactor pressure exceeds a predetermined threshold. In the event of fault or failure of the compactor pressure sensor, for instance, if the signal from the compactor pressure sensor is not within a correct range, or is absent, the controller can be programmed to raise the compactor when the compactor lowering time exceeds a predetermined threshold. 
   According to another preferred aspect of the invention, the auger pressure sensor is operable to sense pressure as the auger or augers move or distribute cotton over the compacted cotton in the bottom of the chamber. During normal operation, the auger pressure signal is used as an index for lowering the compactor, and to determine at what level to raise the compactor above the compacted cotton. In the event of fault or failure of the auger pressure sensor, for instance, if the signal from the auger pressure sensor is not within a correct range, or is absent, the controller can be programmed to lower the compactor when the time for staying above the cotton exceeds a predetermined threshold. 
   According to still another preferred aspect of the invention, the controller is programmed to check the operability or status of critical operator switches during key up or start up, such as, but not limited to, a door open operator switch, a door close operator switch, a fire unload operator switch, and an unload chain operator switch, and if one or more of the switches is faulty, to prevent execution of the commanded operation, and output or display a message or error signal to the operator, to turn off the switch and/or check the wiring harness, connections, and/or to take other troubleshooting steps. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of a cotton harvester including an on-board cotton module builder or packager operable according to the method of the invention; 
       FIG. 2  is a simplified schematic top view of compactor of the cotton harvester of  FIG. 1 ; 
       FIG. 3  is a simplified schematic diagram of a cotton packager controller operable using methods according to the invention; 
       FIG. 4  is a high level flow diagram showing steps for operation of the controller according to one of the methods of the invention; and 
       FIG. 5  is another high level flow diagram showing steps for operation of the controller according to another method of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning now to the drawings, in  FIG. 1 , a cotton harvester  10  is shown, including an on-board cotton packager or module builder  12  for compacting cotton harvested by harvester  10  into a unitary cotton module (not shown). 
   Referring also to  FIG. 2 , a compactor  14  operable according to the present invention is shown. Compactor  14  includes a compactor frame  16  which is oriented generally horizontally, or within a range of small acute angles relative to horizontal, and substantially entirely disposed within a compactor chamber  18 , for movement downwardly against cotton contained therein for compacting the cotton against a floor  20  therein. Compactor frame  16  includes a front cross member  22  disposed in chamber  18  adjacent a front wall  24 , and having opposite ends which extends through sidewardly open slots  26  in the sides of module builder  12 . Similarly, a rear cross member  28  is disposed in chamber  18  and has opposite end portions which extend through slots  30  in sides of module builder  12 . Augers  32  are supported in forward and rearward extending relation between cross members  22  and  28  within chamber  18 . Augers  32  can be rotated using any suitable commercially available drivers, such as a gear drive driven by a motor such as a fluid or electric motor, or directly by fluid or electric motors, as desired, and as controlled by an auger on solenoid  34  and an auger reverse solenoid  36  ( FIG. 3 ), for distributing the collected cotton in chamber  18  as will be explained. In this regard, it should be noted that it is desirable and a sought after feature to distribute the cotton evenly with respect to the plane of floor  20 , such that the resultant compacted cotton module will have a substantially uniform height along its length and width. 
   Compactor frame  16  of compactor  14  is supported in compacting chamber  18  on each side by an exterior side structure  38 , each structure  38  including a forwardly and rearwardly extending main beam  40  which extends between and connects front and rear cross members  22  and  28 . Each side structure  38  additionally includes a pair of braces  42  which extend downwardly and at converging angles from front and rear cross members  22  and  28 , and which are connected together by a gusset  44  located spacedly below about the middle of main beam  40 . Here, it should be noted that compactor frame  16  located within compacting chamber  18  and exterior side structures  38  on the exterior of module builder  12  are movable upwardly and downwardly together. 
   The upward and downward movement of exterior side structures  38  and compactor frame  16  is preferably achieved and controlled by fluid cylinders  46  extending, respectively, between gussets  44  of each exterior side structure  38  and a support frame  48  supported by and extending upwardly from a frame  50  of module builder  12 . Importantly, a rod  52  of each cylinder  46  is connected to gusset  44  at a pivot  54  which allows limited pivotal movement of side structure  38  and thus compactor frame  16  and augers  32  of compactor  14  about a side-to-side extending pivotal axis within a limited range of pivotal movement. 
   Support frame  48  on each side of module builder  12  includes a pair of diagonally extending braces  56  having lower ends connected to frame  50 , and upper ends which connect to and support vertical braces  58  which support a cross member  60  to which fluid cylinder  46  is attached. A more forward brace  56  of support frame  48  on that side of module builder  12  facing outwardly from the page, and the more rearwardly located brace  56  on the opposite side of the module builder, support forward and rear compactor position sensors  62 A and  62 B, respectively. Each compactor position sensor  62 A and  62 B includes an elongate actuator arm  64  which pivotally connects to gusset  44  on that side of the module builder. Each sensor  62 A and  62 B is a rotary type sensor, which will detect rotational movement of the respective actuator arm  64 , as compactor  14  is moved from the position shown in  FIG. 1 , for instance, to any of several lowered positions (not shown). Because two compactor position sensors  62 A and  62 B are used, movements of compactor  14  at a tilt will result in different rotational displacements of actuator arms  64  of the respective sensors  62 A and  62 B, and thus the sensors will output different positional values. The difference between these positional values can be utilized for determining both the vertical position of compactor  14 , and also any tilt thereof. Compactor position sensors can include, for instance, potentiometers, which vary a voltage or current signal when an input thereof is rotated. Actuator arms  64  can be slidable relative to the input to prevent binding when rotated. For instance, a vertical position of the compactor can be determined as a function of a sum of the values outputted by sensors  62 A and  62 B, such as by averaging the values. 
   Referring also to  FIG. 3 , a compactor controller  66  of packager  12  is operable for receiving signals outputted by a number of devices, including, but not limited to, a compactor pressure signal from a compactor pressure sensor  68 , two compactor position signals outputted by compactor position sensors  62 A and  62 B, auger pressure signals outputted by an auger pressure sensor  70 , and one or more additional signals outputted by various sensors or other devices. Controller  66  can be connected to the sensors using any suitable conductive paths, such as, but not limited to, a conventional wiring harness, optical cables, a wireless network, or the like. Responsive to the signals from these devices, and/or other devices, controller  66  is operable for automatically responsively outputting signals to apparatus such as a compactor raise solenoid  72  and a compactor lower solenoid  74 , which control fluid cylinders  46  ( FIG. 1 ) operable for moving compactor  14  upwardly and downwardly against cotton accumulated in a bottom region of compactor chamber  18 . The cylinders  46  can also be used for setting or indexing the compactor position. Compactor controller  66  is also operable for outputting signals to augers  32  ( FIGS. 1 and 2 ), for effecting forward or reverse rotation thereof via auger on solenoid  34  and auger reverse solenoid  36 , and to other suitable devices. 
   As indicated above, compactor controller  66  is preferably programmed for automatically controlling compactor and auger operation for building a compacted cotton module within compactor chamber  18 , as a function of the outputs from the sensors, time, and other parameters, as harvester  10  is operating. However, failure or fault of a sensor or sensors, and/or of the conductive path connecting a sensor or sensors to controller  66 , either of a continuous, intermittent, or erratic manner, could result in a lack of complete data required for normal automatic programmed operation of compactor  14 . As a result, compactor  14  could be shut down, either automatically or by an operator, to allow diagnosis and correction of the failure or fault, thereby interrupting the harvesting operation. The methods of the present invention provide alternatives to allow continued operation of the compactor under several sensor fault or failure conditions. 
   Referring also to  FIG. 4 , a high level flow diagram  76  is shown, including preferred steps for operation of compactor controller  66  in a fault tolerant mode, wherein one or both compactor position sensors  62 A and  62 B have failed or are faulty, and/or a conductive path in connection therewith is faulty. In this mode, controller  66  will determine or set a compactor position value, that is, the position of compactor  14  in relation to some reference, and a compactor tilt value, if any, for use, for instance, in determining the location of compactor  14  in chamber  18 , or whether a movement or indexing of compactor  14  is required. At decision block  78 , controller  66  determines if there is a failure or fault with rear compactor position sensor  62 B. This can be determined from outputs from the sensor, or lack thereof. For instance, a value of an output from the signal can be outside of prescribed range of values, or above or below some prescribed threshold. If a fault is determined, controller  66  will set a rear calculated compactor position value equal to a front calculated compactor position value, as denoted at block  80 . If no fault is determined, controller  66  proceeds to determine if there is a failure or fault with front compactor position sensor  62 A, as denoted at decision block  82 . This determination can be made based on the same or different parameters as those used for determining a fault of sensor  62 B. If a fault is determined, controller  66  sets the front calculated compactor position value equal to the rear calculated compactor position value, as denoted at block  84 . If no fault is determined, controller  66  will proceed to set or determine a compactor position value equal to a value which is a function of a sum of the front calculated compactor position value and the rear calculated compactor position value, as denoted at block  86 . For instance, an average of the position values can be calculated. Additionally, controller  66  will set a compactor tilt value equal to a value which is a function of a difference between the rear calculated compactor position value and the front calculated compactor position value. As denoted at decision block  88 , if controller  66  determines that a failure or fault condition exists in regard to both sensors  62 A and  62 B, it will set the compactor position value equal to a default value, which is preferably a bottom position for the compactor, and will set the compactor tilt value equal to a default value, which is preferably zero tilt, as denoted at block  90 . If, at decision block  88 , controller  66  determines that there is no failure of both sensors  62 A and  62 B, the compactor position and tilt values set as indicated in block  86  will be used. 
   As a result, in the event of a fault or failure of one or both of compactor position sensors  62 A and  62 B, or of a conductive path connecting sensors  62 A and  62 B to controller  66 , a compactor position value is determined, such that compactor  14  is still able to operate in a reasonably effective manner. For instance, even if compactor  14  is tilted but a sensor failure makes it impossible to determine the existence of the tilt, controller  66  can operate augers  32  in a default mode. As an example, the augers can be operated in one direction for a first operating period, then reversed and operated in the opposite direction for another time period, such that at least some additional distribution of cotton beneath the compactor will occur before the next compacting operation. A default compaction stroking routine can also be used, such that the cotton in the bottom of the chamber can be compacted to at least some extent, to facilitate receipt of additional cotton into the chamber during continued harvesting. Thus, although optimal module building may not occur in the event of failure of one or both of the compactor position sensors  62 A and  62 B, a reasonably effective compaction routine is provided. 
   Referring also to  FIG. 5 , a high level flow diagram is shown, including preferred steps for operation of compactor controller  66  in a fault tolerant mode in the event of a faulty auger pressure signal, or absence thereof. At block  94 , augers  32  are operating to distribute cotton within compactor chamber  18 . Controller  66  will determine if an auger pressure signal is present, as denoted at decision block  96 . If yes, controller  66  will determine whether the signal is good, for instance, within a predetermined or correct value range, as denoted at block  98 . If yes, controller  66  will operate the compactor in the normal manner, for instance, responsive to auger pressure signals, as denoted at block  100 . Returning to decision blocks  96  and  98 , if controller  66  determines that the auger pressure signal is not present, or is not within the correct range, controller  66  will operate in a fault tolerance mode, which can involve, for instance, operation of augers  32  for a predetermined auger operation time period. Controller  66  will time the operation, and determine when the auger operation time is expired, as denoted at decision block  102 , then will proceed to lower the compactor to perform one or more compacting strokes, as denoted at block  104 . 
   During normal operation, controller  66  will raise the compactor if the compactor pressure exceeds a predetermined threshold. In the event of fault or failure of the compactor pressure sensor  68 , for instance, if the signal from compactor pressure sensor  68  is not within a correct range, or is absent, controller  66  can be programmed to operate in a mode tolerant of this fault, for instance, to raise compactor  14  when a prescribed compactor lowering time exceeds a predetermined threshold. 
   Still further, there are some fault conditions wherein continued operation is not desirable until the fault is corrected. For instance, in this regard, controller  66  can be programmed to check the operability or status of critical operator switches during key up or start up, such as, but not limited to, a door open operator switch, a door close operator switch, a fire unload operator switch, and an unload chain operator switch (not shown), and if one or more of the switches is faulty, to prevent execution of the operation commanded by the switch, and output or display a message or error signal to the operator, to turn off the switch and/or check the wiring harness, connections, and/or to take other troubleshooting steps. 
   It will be understood that changes in the details, materials, steps, and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates several preferred embodiments of methods of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.