Abstract:
A method according to an exemplary aspect of this disclosure includes, among other things, electrically diagnosing a failure of a brushless DC motor of a surgical device.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/930,125, filed Jan. 22, 2014, the entirety of which is herein incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Battery and electric powered surgical devices are commonly used in performing orthopedic surgical procedures in arthroscopic, endoscopic, large bone and small bone orthopedics. Typically, these surgical devices include a tool mounted at a distal end. Example tools include rotary shavers, drills, and cutting accessories such as sagittal and reciprocating saws. The surgical devices may also include a motor, such as a brushless DC (BLDC) motor, including a permanent magnet and a plurality of stators. The motor may also include Hall effect sensors for monitoring a position of the permanent magnet during operation of the motor. 
       SUMMARY 
       [0003]    A method according to an exemplary aspect of this disclosure includes, among other things, electrically diagnosing a failure of a brushless DC motor of a surgical device. 
         [0004]    In a further non-limiting embodiment of the foregoing method, the method includes determining whether there has been a failure of a Hall effect sensor of the surgical device. 
         [0005]    In a further non-limiting embodiment of the foregoing method, the surgical device includes a plurality of Hall effect sensors. Further, the method includes determining which of the Hall effect sensors of the surgical device have failed. 
         [0006]    In a further non-limiting embodiment of the foregoing method, the method includes illuminating a light associated with the failed Hall effect sensor. 
         [0007]    In a further non-limiting embodiment of the foregoing method, the light is illuminated a first color to indicate that the Hall effect sensor has failed, and the light is illuminated a second color to indicate that the Hall effect sensor is operating normally. 
         [0008]    In a further non-limiting embodiment of the foregoing method, the light is mounted to one of (1) the surgical device, and (2) a unit electrically coupled to the surgical device. 
         [0009]    In a further non-limiting embodiment of the foregoing method, the method further includes determining whether the brushless DC motor is exceeding a no-load torque. 
         [0010]    In a further non-limiting embodiment of the foregoing method, the method further includes illuminating a light to indicate that the brushless DC motor is exceeding a no-load torque. 
         [0011]    In a further non-limiting embodiment of the foregoing method, the method further includes determining whether the brushless DC motor is exceeding a threshold current level within a time window. 
         [0012]    In a further non-limiting embodiment of the foregoing method, the method further includes recording and storing data indicative of the current drawn by the brushless DC motor over time. 
         [0013]    In a further non-limiting embodiment of the foregoing method, the method further includes determining whether preventative maintenance of the brushless DC motor is required. 
         [0014]    In a further non-limiting embodiment of the foregoing method, the method further includes selecting an appropriate motor monitoring profile based on a tool type. 
         [0015]    A surgical device according to an exemplary aspect of the present disclosure includes, among other things, a brushless DC motor and a battery pack including circuitry configured to diagnose a failure of the brushless DC motor. 
         [0016]    In a further non-limiting embodiment of the foregoing surgical device, the battery pack includes a plurality of batteries to power the brushless DC motor. 
         [0017]    In a further non-limiting embodiment of the foregoing surgical device, the brushless DC motor includes a plurality of Hall effect sensors, and the battery pack includes a plurality of lights corresponding to a respective one of the Hall effect sensors. 
         [0018]    In a further non-limiting embodiment of the foregoing surgical device, the circuitry is configured to determine whether any of the plurality of Hall effect sensors have failed. 
         [0019]    In a further non-limiting embodiment of the foregoing surgical device, the circuitry is further configured to illuminate a light on the battery pack corresponding to a failed Hall effect sensor. 
         [0020]    A system for diagnosing a motor of a surgical device according to an exemplary aspect of the present disclosure includes, among other things, a surgical device including a brushless DC motor, and control unit electrically coupled to the surgical device. The control unit is configured to diagnose a failure of the brushless DC motor. 
         [0021]    In a further non-limiting embodiment of the foregoing system, the brushless DC motor includes a plurality of Hall effect sensors, and wherein control unit is configured to determine whether any of the plurality of Hall effect sensors have failed. 
         [0022]    In a further non-limiting embodiment of the foregoing system, the control unit is configured to determine whether the brushless DC motor is exceeding a no-load torque. 
         [0023]    The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The drawings can be briefly described as follows: 
           [0025]      FIG. 1A  illustrates an example control system for a surgical device. 
           [0026]      FIG. 1B  illustrates an example diagnostic system. 
           [0027]      FIG. 2  is a cross-sectional view taken along line  2 - 2  from  FIG. 1A , and illustrates a portion of an example motor. 
           [0028]      FIG. 3  illustrates an example method, including steps to monitor motor performance and to diagnose a failed motor. 
           [0029]      FIG. 4A  illustrates another example surgical device. 
           [0030]      FIG. 4B  is an end view of the surgical device of  FIG. 4A . 
       
    
    
     DETAILED DESCRIPTION 
       [0031]      FIG. 1A  schematically illustrates a control system  10  for operating a surgical device  12 . In this example, the surgical device  12  includes a motor  14  (illustrated in phantom in  FIG. 1A ) for driving a tool  16  at a distal end of the surgical device  12 . Example tools  16  include rotary shavers, drills, and sagittal and reciprocating saws. Other types of tools come within the scope of this disclosure. 
         [0032]    The control system  10  further includes a control unit  18 . In this example, the control unit  18  includes a power supply that provides electrical power to the surgical device  12 . Alternatively, the surgical device  12  may include a DC battery pack that powers the motor  14 . In either case, the control unit  18  may further include memory, hardware, and software configured to control operation of the surgical device  12 . 
         [0033]    The example control unit  18  includes a display  20 , one or more LED indicator lights  22  (only one illustrated), one or more adjustors  24  (e.g., a dial, only one illustrated), and a plurality of electrical inlet/outlet ports  26 ,  28  (only two illustrated). The control system  10  may optionally include a foot switch  30  including a plurality of switches  32 ,  34 ,  36 , which allow a surgeon to control the surgical device  12  at least partially with his or her feet. Additional surgical devices  12  may be connected to the control unit  18  at one time. 
         [0034]      FIG. 1B  illustrates an example diagnostic system  38 . The diagnostic system  38  is used to diagnose a motor  14  of the surgical device  12 , as will be explained in detail below. In the illustrated example, the diagnostic system  38  includes a diagnostic control unit  40 , which, in this example, includes a plurality of LED lights  42 A- 42 D, a display  44 , and an electrical inlet/outlet port  46 . Like the control unit  18 , the diagnostic control unit  40  may include a power source, memory, hardware, and software configured to diagnose the motor  14 . In general, the diagnostic system  38  uses the electrical connection between the motor  14  and the power source to identify if any Hall effect sensors H 1 -H 3  ( FIG. 2 ) of the motor  14  have failed. Alternatively, the diagnostic system  38  uses the electrical connection to determine if the motor  14  is using a specified current draw associated with a good motor. 
         [0035]    The systems  10  and  38  may be separate systems, as illustrated in  FIGS. 1A and 1B . On the other hand, the control system  10  could be modified to incorporate the features of the diagnostic system  38 , or vice versa. That is, in one example, the control unit  18  is used to control the surgical device  12 , and is also used to diagnose a failure of the motor  14 . 
         [0036]    As mentioned, the surgical device  12  may include a motor  14  configured to drive the tool  16 . In one example, the motor  14  is a brushless DC (BLDC) motor. The motor  14  may further be a slotted or slotless BLDC motor.  FIG. 2  schematically illustrates an example BLDC motor  14 , which includes a permanent magnet  48  configured to rotate about an axis  50 . Rotation of the permanent magnet  48  is translated into movement of the tool  16  using one or more known mechanical connectors. 
         [0037]    As illustrated in  FIG. 2 , the permanent magnet  48  is surrounded by a plurality of stators  52 ,  54 ,  56 . In this example, there are three stators  52 ,  54 ,  56  circumferentially arranged about the axis  50 , and spaced approximately 120° apart from one another. While three stators are illustrated, this disclosure extends to motors  14  including different numbers of stators. 
         [0038]    Each of the stators  52 ,  54 ,  56  supports a respective coil winding W 1 -W 3 , each of which is in communication with the power supply of the control unit  18 . The example motor  14  further includes a plurality of Hall effect sensors H 1 -H 3  mounted to a respective stator  52 ,  54 ,  56 . Each of the Hall effect sensors H 1 -H 3  are in communication with the control unit  18 , and are used to essentially report a position of the permanent magnet  48  to the control unit  18 . The control unit  18  provides an appropriate level of current to the windings W 1 -W 3  depending on the signals received from the Hall effect sensors H 1 -H 3 . 
         [0039]    During operation of the surgical device  12 , the motor  14  may fail. As used herein, the term “failure” refers to a motor  14  that is operating below an optimal level. The term “optimal level” in this disclosure refers to a minimal threshold operational level, which may be a pre-established level corresponding to an acceptable level of performance required for surgery. 
         [0040]    A failure of the motor  14  may be caused by a defect in one of the Hall effect sensors H 1 -H 3 . A failure of the motor  14  may also be indicated if the motor  14  operates at an unacceptable no-load torque level. As is known in the art, no-load torque is the torque developed at full motor speed without torque-loading the motor. A failure of one of the Hall effect sensors H 1 -H 3  may be related to, or may be independent from, the motor  14  operating an unacceptable no-load torque. 
         [0041]    In one example method, shown in  FIG. 3 , the performance of the motor  14  is monitored by the control unit  18 . Initially, the control unit  18  may store one or more motor monitoring profiles. These profiles may be associated with a particular tool and/or motor. For instance, the response of the motor  14  when the tool  16  is a shaver will be different than when the motor  14  is used within a drill (such as in  FIG. 4 ). Based on the type of tool, a particular motor monitoring profile is selected at  58 . The motor monitoring profile includes various thresholds, constants, and algorithms associated with the particular tool and/or motor type. 
         [0042]    Next, using the selected profile, the control unit  18  periodically or continually determines whether the performance is optimal, at  60 . Even if the performance is optimal, the control unit  18 , at  61 , may also trigger an alert that the motor  14  may need preventative maintenance. This alert could be triggered based on the amount of time the motor  14  has been in use during its lifetime. Additionally, it could be possible that a bearing, gear, or other mechanical component associated with the motor is beginning to fail and causing the motor to work harder. In this respect, the entire device (not just the motor) may be sent for preventative maintenance. At  62 , the control unit  18  indicates a failure if the performance of the motor  14  is not optimal. In one example, alerts for motor maintenance and motor failure are communicated to the user by way of a light, such as the LED light  22 . Alternatively, or in addition, a message could be communicated to a user via the display  20 . 
         [0043]    In one example, after a motor failure has been indicated, the user sends a particular surgical device  12  back to the original manufacturer. The original manufacturer may then connect the surgical device  12  to the diagnostic control unit  40 . The diagnostic control unit  40  is capable of electrically diagnosing the failure of the motor  14 . 
         [0044]    In one example, that diagnosis includes determining, at  64 , whether one of the Hall effect sensors H 1 -H 3  has failed. If one or more of the Hall effect sensors have failed, the diagnostic control unit  40  then determines, at  66 , which of the particular Hall effect sensors H 1 -H 3  have failed. In one example, the diagnostic control unit  40  identifies a failure of the Hall effect sensors H 1 -H 3  by monitoring the voltage generated by each sensor. In this example, there is a pre-established, acceptable lower voltage range and an acceptable upper voltage range. If, during operation, the Hall effect sensors H 1 -H 3  are operating outside of the acceptable lower voltage range when in a low voltage condition, or outside the acceptable upper voltage range when in a high voltage condition, a failure is triggered. The information discovered at  66  may be communicated to a user in any manner. In one example, the lights  42 A- 42 C illuminate either green or red, indicating normal operation or a failure respectively, for each of the Hall effect sensors H 1 -H 3 . 
         [0045]    Further, at  68 , the diagnostic control unit  40  may determine if there is another issue with the motor  14 , such as the motor  14  operating outside an acceptable no-load torque range. Information regarding the no-load torque of the motor  14  may be communicated to the user via the LED light  42 D, or in another manner. 
         [0046]    Additionally, at  69   a,  the control unit  18  may also monitor—and optionally record, at  69   b —the amount of current drawn by the motor  14  over time. High current draws in a short period of time could indicate that the motor  14  is exceeding a maximum operating temperature. Additionally, it may indicate that electrical components associated with the motor  14 , such as a cable assembly electrically coupling the motor  14  to the control unit  18 , are exceeding a maximum operating temperature. If a threshold current level (for either the motor or the cable assembly) within a time window is exceeded, this event can be communicated to the user using a light, as in the above examples, or in any other manner. At  69   b,  the control unit  18  can be configured to record and store the current and time data, for both the motor  14  and the cable assembly, throughout the life of the motor  14 . If a failure of the motor  14  occurs, an analyst can review the current versus time log. This information may be useful in identifying the cause of the failure. 
         [0047]    The method of  FIG. 3  provides detailed information about the failure of the motor  14 , which may be useful to the original manufacturer in order to make necessary repairs and assess whether future design changes may be needed. While the above discussion specifically mentions the Hall effect sensors H 1 -H 3  and no-load torque, the diagnostic control unit  40  may be configured to recognize additional defects in the motor  14 . 
         [0048]    While the steps for monitoring performance of the motor  14  and diagnosing the motor  14  have been illustrated together in  FIG. 3 , it should be understood that these steps may be performed separately. As explained above, the control system  10  may perform the steps  58 ,  60 , and  62 , while the diagnostic system  38  may perform the steps  64 ,  66 , and  68 . Again, however, the control system  10  could perform all of the steps illustrated in  FIG. 3 . 
         [0049]    While  FIGS. 1A-1B  illustrate the control unit  18  and the diagnostic control unit  40  as being separate units, the control unit  18  and the diagnostic control unit  40  could be incorporated into a single surgical device. One example of such a surgical device  70  is illustrated in  FIG. 4A . The device  70  is configured to support a tool  71  at a distal end. As illustrated, the device  70  is a drill, and the tool  71  is a drill bit supported by a collet  72 . Other tools, such as those mentioned above, come within the scope of this disclosure. 
         [0050]    In this example, the tool  71  is driven by a motor  74  (illustrated in phantom). The surgical device  70  further includes a battery pack portion  76 , which in one example is clipped into the base of the surgical device  70 . The battery pack portion  76  may alternatively be integral to the surgical device  70 . The battery pack portion  76  includes a plurality of batteries  78  to provide power to the motor  74 . The batteries  78  may be rechargeable. 
         [0051]    The battery pack portion  76  further includes control circuitry  80  (shown in phantom) configured to drive the motor  74  and diagnose the motor  74 . That is, the control circuitry  80  is configured to perform the functions of the control unit  18  and the diagnostic control unit  40 , as substantially described above. 
         [0052]    As illustrated in  FIG. 4B , which is an end view of the surgical device  70 , the battery pack portion  76  may include a plurality of LED lights  82 ,  84 ,  86 , and  88 . In this example, the lights  82 ,  84 ,  86  illuminate to indicate the performance of the hall sensors H 1 -H 3 , respectively, as substantially described above (e.g., the lights  82 ,  84 ,  86  could illuminate either “red” or “green”). Similarly, a fourth light  88  may illuminate to indicate the no-load torque of the motor  74 . 
         [0053]    It should be understood that terms such as “distal” and “proximal” have been used herein for purposes of explanation, and should not be considered otherwise limiting. Terms such as “generally,” “substantially,” and “about” are not intended to be boundaryless terms, and should be interpreted consistent with the way one skilled in the art would interpret the term. 
         [0054]    Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. 
         [0055]    One of ordinary skill in this art would understand that the above-described embodiments are exemplary and non-limiting. That is, modifications of this disclosure would come within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.