Abstract:
Disclosed are systems and methods for reducing vibration in a device mounting structure, the method including determining when the vibration level of the device mounting structure exceeds a first threshold, and reducing the data transfer rate of at least one data transfer device mounted to the device mounting structure an amount sufficient to reduce the vibration to a level below a second threshold.

Description:
BACKGROUND 
     In some situations, vibration of a housing or other mounting structure can cause one or more of the devices within that housing or otherwise attached to such a mounting structure to malfunction. For example, one piece of equipment may function perfectly well in one environment, but when that same piece of equipment is placed in proximity to other equipment, the vibrations from that other equipment may, when combined with vibration generated internal to the equipment in question, cause the equipment in question to malfunction. 
     In some situations, the operation of the equipment itself may, under some circumstances, be enough to cause malfunctioning of the equipment. This is particularly true as the data transfer rates of equipment continues to increase. This increase in data transfer rates translates, in some situations, to increased vibrations, which, in turn, may cause malfunctions to occur. 
     SUMMARY 
     In one embodiment, vibration reduction in a device mounting structure is achieved by determining when the vibration level of the device mounting structure exceeds a first threshold, and reducing the data transfer rate of at least one data transfer device mounted within the device mounting structure an amount sufficient to reduce the vibration to a level below a second threshold. 
     In another embodiment, a system for reducing vibrations in a device is provided, said system comprising circuitry for generating a signal corresponding to the vibration level of said device, comparator circuitry for comparing generated ones of said vibration level signals against known vibration level signals of said device, and means for providing a control signal when a compared vibration level signal is outside an accepted range. 
     A further embodiment provides a system for reducing vibrations in a device, said system comprising means for generating a signal corresponding to the vibration level of said device, means for comparing generated ones of said vibration level signals against known vibration level signals of said device, and means for providing a control signal when a compared vibration level signal is outside an accepted range. 
     Another embodiment provides a method for determining which of a plurality of devices to use at any given time, said method comprising determining from a vibration level of a given device if such device is suitable for using at said given time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows one embodiment of a system using the teachings of the inventive concept; 
         FIG. 2  is a block schematic diagram of one embodiment of the operation of the teachings of the inventive concept; 
         FIG. 3  is a flow chart showing one illustrative embodiment of the generation of a desired vibration level; and 
         FIG. 4  is a flow chart showing one embodiment according to the teachings of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Turning now to  FIG. 1 , there is shown one embodiment of the teachings of the inventive concept showing system  10  in which drive cage  13  has mounted within it a plurality of data transfer devices  14 - 1  through  14 -N, such as may comprise disk drives comprising a RAID array. RAID circuit  15  (shown in schematic form in  FIG. 2 ) may also be included within system  10 . Also associated with drive cage  13  is accelerometer  11  connected to cage  13 . Accelerometer could, for example be a tri-axial accelerometer, and could be on the outside of drive cage  13 , or mounted within drive cage  13 , the purpose being to create a signal (for example, an amplitude and frequency signal) showing the vibration amplitude of drive cage  13  for various vibration frequencies. Typically, the frequency of vibration would be between 0 and 700 Hz. The precise frequency and frequency range would depend upon the product or devices being protected. Accelerometer  11  of one embodiment is designed to provide a broadband spectrum response over a range of frequencies. 
     In operation according to one embodiment, accelerometer  11  continuously monitors the frequency and amplitude of the vibration produced by drive cage  13  (or, if desired, by a particular device with cage  13 ) and provides that input for monitoring and comparison against a known standard for the particular device(s) of concern. Monitor signal of accelerometer  11  would typically describe a curve within a set of boundaries. When the frequency and/or amplitude of vibrations monitored by accelerometer  11  exceeds a given curve (for example, exceeds 2 gs at 4,000 Hz) a control signal may be generated, whether internally by accelerometer  11  or by a system coupled thereto. In one embodiment, this control signal is communicated via cable  12  to RAID circuit  15 . Circuit  15 , in turn, operates to reduce (or turn off) the data transfer rate of one or more of devices  14 - 1  through  14 -N. According to one embodiment, this operation reduces the vibrations associated with operation of the devices in the cage and also protects the data transfer from jiggling and therefore data loss. 
     In the example discussed, slowing down the data transfer rate of a data transfer device reduces the vibration it causes. Also, by slowing down the data transfer rate of all of the data transfer devices in cage  13 , these devices are less prone to error caused by vibration. Such vibration could be because of a building vibration or could be because equipment in close proximity to drive cage  13  is setting up a vibration in drive cage  13 . 
     It should be appreciated that, in operation, system  10  could reduce one data transfer unit, or all the data transfer units. Moreover, such reduction need not be equally applied within cage  13 . 
     Device  16  is used, if desired, to induce known vibration to cage  13  for calibration purposes. For example, device  16  may be utilized to empirically determine vibration frequencies and/or amplitudes at which degraded performance of data transfer devices  14 - 1  through  14 -N is experienced for setting control threshold values according to embodiments of the invention. Additionally or alternatively, device  16  may be utilized in determining data transfer rate adjustments suitable for addressing particular vibration frequencies and/or amplitudes. 
       FIG. 2  shows a block schematic diagram of one embodiment of the operation of the teachings of the inventive concept. As shown in  FIG. 2 , accelerometer  11  within system  20  provides a signal, which in the embodiment discussed is an amplitude (and/or frequency) curve. This signal is provided via cable  12  to circuit  15 , which has associated therewith CPU  21  and data base  22 . Circuit  15  could be a RAID circuit if desired and could be located within cage  13  or remote therefrom. Cable  12  could be replaced with a wireless transmitter if desired. Circuit  15  matches the currently provided signal from accelerometer  11  against one or more signal curves, as stored in data base  22 , to determine if the vibration level of drive cage  13  exceeds a desired amount. If it does not, then data transfer devices  14 - 1  through  14 -N are allowed to operate at their normal speed or at their present settings. If, however, the current vibration exceeds the desired vibration level then the circuit operates to reduce the data transfer rate of at least one of data transfer devices  14 - 1  through  14 -N. As discussed, this reduction could be by turning one or more devices off, by reducing the data transfer rate of one or more devices via signals sent over path  202 , or combination thereof. 
     Turning now to  FIG. 3 , there is shown a flow chart of one embodiment of the generation of a desired vibration level for establishing standard reference signal levels for vibration which will then be utilized to compare against subsequent vibration signals to determined if action needs be taken. Process  301 , if desired, may be used to set the number of different signal levels desired. These levels could be established so that a user from time to time could select different acceptable vibration levels for a particular device. 
     Process  302  determines whether any signal levels are user supplied. This again is optional. If the user supplies a known signal, process  303  controls how this signal is to be obtained from the user. If there are no user supplied levels, then the system optionally, under process  304 , induces known vibration (for example, via device  16   FIG. 1 ) into drive cage  13 . In process  305  the signal is captured from accelerometer  11  via circuit,  15 ,  FIG. 2 . The captured signal is then stored in data base  22 , for example under control of CPU  21  as shown by process  306 . After this recording is complete the system then checks, via process  307 , to see if there are more levels to be established. If there are, then processes  304 ,  305 , and  306  are repeated until all of the desired levels have been set. At that point the process ends. 
     Turning now to  FIG. 4 , there is shown a flow chart of one embodiment  40  of the teachings of the invention. Process  401  compares a recent accelerometer signal obtained from accelerometer  111  against a standard. This standard could be the only signal in data base  22  ( FIG. 1 ) pertaining to the system being tested or could be a standard that is selected from among several, via process  402 . Some of the signals could be provided, if desired, live from the user and not stored previously if desired. 
     Process  403  determines if the signal is too high, e.g., the amplitude at a certain frequency is outside of a given range. This can be accomplished by well-known signal level comparitor devices, such as one of the many integrated circuit comparitors available today, or as may be implemented in software. 
     In process  404 , if the vibration signal that is currently being received is out of range then a control signal is sent and this signal is received by process  405  and is used to adjust the data transfer rate of one or more of data transfer devices  14 - 1  to  14 -N (as discussed above). The system then compares the new vibration signal (after adjustment), via process  406 , and if the signal is still too high, via process  407 , then an additional speed reduction is initiated via process  404  and  405 . Again, if desired, the accelerometer signal is compared to see if the vibration signal is within the acceptable range. If it is, then the whole process repeats via process  401 . 
     The system can be set to monitor vibration even when no data is being transferred, or data transfer is off. Such an embodiment might be desired because, if extrinsic vibration is too high, other data transfer devices in other locations might be used to reduce errors. This, for example, could be controlled via process  408 , which signals that this device is available when the signal level (vibration) is not too high. Process  409  signals to select another device when vibration of this device is higher than desired. 
     It should be noted that while the illustrative embodiment has focused on data transfer devices, such as disk drives or printers, other devices, e.g., any devices which are the source of vibration and/or is susceptible to the effects of vibration such as fans, scanners, and the like, may be subject to the same control. Also the device which suffers from excess vibration may not be the device which causes such vibration. Thus, it may be desirable to reduce a parameter of a device other than a data transfer device to achieve the desired results.