Source: http://www.google.com/patents/US6977477?dq=6,970,917
Timestamp: 2017-10-21 13:24:34
Document Index: 633683013

Matched Legal Cases: ['art 100', 'art 200', 'art 300', 'art 400', 'art 1800', 'art 1900', 'art 2000', 'art 2100']

Patent US6977477 - Systems, apparatus, and methods for motor control - Google Patents
Systems and methods are provided through which the current to a spindle motor of the recording medium of a mass storage device is modulated to avoid anomalies in the operation of mass storage device and reduce power consumption. In the example of a disc drive, the current is modulated to prevent expected...http://www.google.com/patents/US6977477?utm_source=gb-gplus-sharePatent US6977477 - Systems, apparatus, and methods for motor control
Publication number US6977477 B2
Also published as US20020063545
Publication number 09995433, 995433, US 6977477 B2, US 6977477B2, US-B2-6977477, US6977477 B2, US6977477B2
Inventors Donald Ray Bloyer, Garry E. Korbel, Matthew E. Hastings
Patent Citations (30), Referenced by (4), Classifications (23), Legal Events (11)
US 6977477 B2
(a) directing current to a motor; and
(b) modulating the current in reference to a predetermined profile that reduces air bearing instability, and in reference to an occurrence of interference associated with an undesired air-bearing stability in an interface between a head and a surface.
2. The method of claim 1, wherein the motor is associated with a spindle and the surface is a disc, wherein the disc and motor are included in a storage device.
3. The method of claim 2, wherein the modulating step (b) further comprises the step of:
(b)(i) modulating the current in reference to a predicted occurrence of interference in the interface between the head and the disc of the storage device that exceeds a predetermined threshold of interference in the interface between the head and the disc of the storage device.
4. The method of claim 3, wherein the modulating step (b)(i) further comprises the steps of:
(b)(i)(2) comparing the lapse of time to the time of a predicted occurrence of interference in the interface between the head and the disc of the storage device that exceeds a predetermined threshold of interference in the interface between the head and the disc of the storage device; and
5. The method of claim 2 wherein the modulating step (b) further comprises the step of:
(b)(i) modulating the current during spin-up of the storage device.
6. The method of claim 2, wherein the modulating step (b) further comprises the step of:
(b)(i) modulating the current during spin-down of the storage device.
7. The method of claim 1, wherein the profile represents a relationship between time and quantity of current, and wherein the modulating step further comprises the steps of:
(b)(1) monitoring a lapse of time;
(b)(2) referencing the representation of a quantity of current in the profile, from the lapse of time; and
(b)(3) modulating the current to the motor in reference to the representation of the quantity of current in the profile.
predetermined profile reduces takeoff air-bearing instability.
(b)(i) increasing the current, in reference to the occurrence of interference in the interface between the head and the surface.
10. A method for generating a profile of modulated current of a spindle motor of a mass storage device, the method comprising steps of:
(a) receiving air-bearing stability performance data of the mass storage device, the data including the quantity of current applied to the spindle motor at a plurality of discrete points in time, and including at least one performance measurement;
11. The method of claim 10, wherein the air-bearing stability further comprises takeoff air-bearing stability.
12. The method of claim 10, wherein the performance data includes a measurement of a drag and a measurement of speed, and the method further comprises:
13. A method for dynamically modulating current based on dynamic performance data during operation of a storage device, the method comprising steps of:
(a) determining interference associated with an undesired air-bearing stability between a head and a storage medium of the storage device, in reference to a performance profile, and in reference to dynamic performance data during operation, the determining step comprising:
wherein not meeting the expected time is an indication of interference; and
(b) modulating current to control the disc in reference to the interference.
14. A method for dynamically modulating current based on dynamic performance data during operation of a storage device, the method comprising steps of:
(a)(ii) comparing the rate of change of speed to a last sample; and
15. The method of claim 14, wherein the sampling step (a)(i) further comprises:
16. The method of claim 14, wherein the sampling step (a)(i) further comprises:
17. The method of claim 14, wherein the sampling step (a)(i) further comprises:
18. An apparatus for controlling a spindle motor of a mass storage device, the apparatus comprising:
20. The apparatus of claim 19, wherein the modulator further comprises:
21. The apparatus of claim 20, wherein the profile referencer identifies a particular quantity or level of current from the lapse of time as an index into the profile.
22. The apparatus of claim 20, wherein the mass storage device further comprises a disc drive.
23. An apparatus to generate a profile of modulated current of a spindle motor of a mass storage device, comprising:
a receiver of performance data of the mass storage device, wherein the data includes a quantity of current applied to the spindle motor at each of a plurality of discrete points in time, and wherein the data also includes at least one air-bearing stability performance measurement;
a determiner of one or more portions of the performance data that indicate a performance inadequacy that exceeds a predetermined threshold or level, wherein the determiner is operably coupled to the receiver, and
This application claims the benefit of U.S. Provisional Application Ser. No. 60/253,217 filed Nov. 27, 2000 under 35 U.S.C. 119(e).
FIG. 1 is a chart 100 of a relationship between input current and time in a conventional mass storage device during initialization. During initialization, also known as spin-up, of the mass storage device, the spindle motor of the mass storage device receives a substantially linear monotonically decreasing quantity of current 110. The current 110 is linearly decreased from the beginning time of the initialization t0 120, through various other times, such as t1 130, t2 140, and t3 150, until a target rotation speed is achieved at time t4 160, after which, a decreased and constant quantity of current 110 is applied to the motor to maintain the target rotation speed.
FIG. 2 is a chart 200 of a relationship between available torque and time in a conventional mass storage device during initialization. In general, the quantity of available torque 210 decreases during spin-up of the disc. The quantity of available torque 210 decreases from the beginning time of the initialization t0 220, through various other times, such as t1 230, t2 240, and t3 250, until a target rotation speed is achieved at time t4 260, after which, no torque is available when the quantity of current input to the motor is held constant, as shown in FIG. 1, to maintain the target rotation speed.
FIG. 3 is a chart 300 of a relationship between rotation speed of the disc and time in a conventional mass storage device during initialization. In general, the rotation speed (RPM) 310 rises during spin-up of the disc. The rotation speed 310 increases from the beginning time of the initialization t0 320, through various other times, such as t1 330, t2 340, and t3 350, until a target rotation speed is achieved at time t4 360. After the target rotation speed is achieved, the rotation speed 310 is held substantially constant through a constant input of current, as shown in FIG. 1.
FIG. 4 is a chart 400 of a relationship between drag and time in a conventional mass storage device during initialization. In general, drag 410, decreases during spin-up of the disc. The drag 410 generally decreases from the beginning time of the initialization t0 420, through various other times, such as t1 430, t2 440, and t3 450, until a rotation speed is achieved at time t4 460. After the target rotation speed is achieved, the drag 410 remains substantially constant through a constant input of current, as shown in FIG. 1.
FIG. 1 is a chart of a relationship between input current and time in a conventional mass storage device during initialization.
FIG. 2 is a chart of a relationship between available torque and time in a conventional mass storage device during initialization.
FIG. 3 is a chart of a relationship between rotation speed of the disc and time in a conventional mass storage device during initialization.
FIG. 4 is a chart of a relationship between drag and time in a conventional mass storage device during initialization.
FIG. 5 is a block diagram that provides a system level overview of the operation of embodiments of the present invention.
FIG. 6 is a flowchart of a method for controlling a spindle motor of a mass storage device, according to an embodiment of the invention.
FIG. 7 is a flowchart of a method for modulating the current in reference to a predetermined profile, according to an embodiment of the invention.
FIG. 8 is a flowchart of a method for modulating the current in reference to a predicted occurrence of interference in the interface between a head and a disc of the mass storage device that exceeds a predetermined threshold of interference in the interface between a head and a disc of the mass storage device, according to an embodiment of the invention.
FIG. 9 is a flowchart of a method for modulating the current, according to an embodiment of the invention.
FIG. 10 is a flowchart of a method for modulating the current, according to an embodiment of the invention.
FIG. 11 is a flowchart of a method for generating a profile of modulated current of a spindle motor of a mass storage device, according to an embodiment of the invention.
FIG. 12 is a flowchart of a method of steps additional to generating a profile of modulated current of a spindle motor of a mass storage device in FIG. 11, according to an embodiment of the invention.
FIG. 13 is a flowchart of a method for dynamically modulating current based on dynamic performance data during operation, according to an embodiment of the invention.
FIG. 14 is a block diagram of an apparatus for controlling a spindle motor of a mass storage device, according to an embodiment of the invention.
FIG. 15 is a block diagram of a current modulator for modulating the current in reference to a predetermined profile, according to an embodiment of the invention.
FIG. 16 is a block diagram of an apparatus for modulating the current in reference to a predicted occurrence of interference in the interface between a head and a disc of the mass storage device that exceeds a predetermined threshold of interference in the interface between a head and a disc of the mass storage device, according to an embodiment of the invention.
FIG. 17 is a block diagram of an apparatus for generating a profile of modulated current of a spindle motor of a mass storage device, according to an embodiment of the invention.
FIG. 18 is a chart of an example of a relationship between input current and time in a mass storage device using the present invention during initialization.
FIG. 19 is a chart of a relationship between available torque and time in a mass storage device using the present invention during initialization.
FIG. 20 is a chart of a relationship between rotation speed of the disc and time in a mass storage device using the present invention during initialization.
FIG. 21 is a chart of a relationship between drag and time in a mass storage device using the present invention during initialization.
FIG. 22 is an exploded view of one embodiment of a disc drive of the present invention.
FIG. 23 is a schematic view of an information handling system.
FIG. 5 is a block diagram that provides a system level overview 500 of the operation of embodiments of the present invention. Embodiments of the invention operate in a multi-processing, multi-threaded operating environment on a computer, such as information handling system 2300 in FIG. 23.
FIG. 6 is a flowchart of a method 600 for controlling a spindle motor of a mass storage device, according to an embodiment of the invention. Method 600 reduces interference in the interface between a head and a disc of the mass storage device.
Method 600 includes directing current to the motor, in block 610. Thereafter, method 600 includes modulating the current, in block 620. In further varying embodiments, the modulating step 610 is performed during spin-up or spin-down of the mass storage device. Varying methods of modulating the current, in block 620, are described in FIGS. 7–10. In block 620, modulating is performed in a manner that reduces the wear on the head and recording medium, yet provides efficient use of the limited power available to the mass storage device. This is accomplished by modulating the current to avoid anomalies in the performance of the mass storage device. The anomalies include the interruption of the air bearing in a disc drive. In one example, the anomalies are avoided by increasing current to the spindle motor to avoid interruption of the air bearing. In another example, current is reduced when there is no expectation of an anomaly, in order to make efficient use of the limited power available to the mass storage device.
FIG. 7 is a flowchart of a method 700 for modulating the current in reference to a predetermined profile, according to an embodiment of the invention. The predetermined profile represents a relationship between time and quantity of current. In one embodiment of the predetermined profile, the predetermined profile is a nonlinear predetermined profile that represents a nonlinear relationship between time and quantity of current. Generation or creation of the profile is described in FIG. 11. In embodiment of method 700, method 700 is an embodiment of the modulating step in block 620 in FIG. 6. In some embodiments, method 700 is performed by apparatus 1500 in FIG. 15.
FIG. 8 is a flowchart of a method 800 for modulating the current in reference to a predicted occurrence of interference in the interface between a head and a disc of the mass storage device that exceeds a predetermined threshold of interference in the interface between a head and a disc of the mass storage device, according to an embodiment of the invention. In one embodiment of method 800, method 800 is an embodiment of the modulating step, in block 620 in FIG. 6. In some embodiments, method 800 is performed by apparatus 1600 in FIG. 16.
FIG. 9 is a flowchart of a method 900 for modulating the current, according to an embodiment of the invention. In one embodiment of method 900, method 900 is an embodiment of the modulating step, in block 620 in FIG. 6.
FIG. 10 is a flowchart of a method 1000 for modulating the current, according to an embodiment of the invention. In one embodiment of method 1000, method 1000 is an embodiment of the modulating step, in block 620 in FIG. 6. Method 1000 includes modulating 1010 the current in reference to a predetermined profile. The predetermined profile is designed to reduce takeoff air-bearing instability in the interface of the head and the disc. Generation or creation of the profile is described in FIG. 11.
FIG. 11 is a flowchart of a method 1100 for generating a profile of modulated current of a spindle motor of a mass storage device, according to an embodiment of the invention. The profile is produced by the process of method 1100.
FIG. 12 is a flowchart of a method 1200 of steps additional to generating a profile of modulated current of a spindle motor of a mass storage device in method 1100 in FIG. 11, according to an embodiment of the invention. In some embodiments, method 1200 is performed in a mass storage device test laboratory, by a dedicated test station. In method 1200, the performance data includes measurement of a drag component and measurement of speed (e.g. RPM).
FIG. 13 is a flowchart of a method 1300 for dynamically modulating current based on dynamic performance data during operation, according to an embodiment of the invention. Method 1300 is performed by a disc storage device.
FIG. 14 is a block diagram of an apparatus 1400 for controlling a spindle motor of a mass storage device, according to an embodiment of the invention. Apparatus 1400 reduces interference in the interface between a head and a disc of the mass storage device. Apparatus 1400 includes a modulator 1450 of current. The current is directed to a spindle motor 1430 of a recording medium 1410 of a mass storage device 1420. The current is modulated by modulator 1450 in a manner that reduces the wear on the head and recording medium, yet provides efficient use of the limited power available to the mass storage device 1420. This is accomplished by modulating the current to avoid anomalies in the performance of the mass storage device 1420. The anomalies include the interruption of the air bearing in disc drive. In one example, the anomalies are avoided by increasing current to the spindle motor to avoid interruption of the air bearing. In another example, current is reduced when there is no expectation of an anomaly, in order to make efficient use of the limited power available to the mass storage device 1420.
FIG. 15 is a block diagram of a current modulator 1500 for modulating the current in reference to a predetermined profile, according to an embodiment of the invention. The predetermined profile represents a relationship between time and quantity of current. In one embodiment of the predetermined profile, the predetermined profile is a nonlinear predetermined profile that represents a nonlinear relationship between time and quantity of current. A method of generation or creation of the profile is described in FIG. 11 and an apparatus that generates or creates the profile is described in FIG. 17. In one embodiment of apparatus 1500, apparatus 1500 is an embodiment of the modulator 1450 in FIG. 14. In some embodiments, apparatus 1500 performs method 700 in FIG. 7.
FIG. 16 is a block diagram of an apparatus 1600 for modulating the current in reference to a predicted occurrence of interference in the interface between a head and a disc of the mass storage device that exceeds a predetermined threshold of interference in the interface between a head and a disc of the mass storage device, according to an embodiment of the invention. In one embodiment of apparatus 1600, apparatus 1600 is an embodiment of the modulator step 1450 in FIG. 14.
FIG. 17 is a block diagram of an apparatus 1700 for generating a profile of modulated current of a spindle motor of a mass storage device, according to an embodiment of the invention. In some embodiments, apparatus 1700 performs method 1100 in FIG. 11.
FIGS. 18–21 illustrate the effect that modulating the current in FIG. 18 has on available torque in FIG. 19, RPM in FIG. 20, and drag in FIG. 21. FIGS. 18–21 contrast with FIGS. 1–4 of conventional systems.
FIG. 18 is a chart 1800 of an example of a relationship between input current and time in a mass storage device using the present invention during initialization. During initialization, also known as spin-up, of the mass storage device, the spindle motor of the mass storage device receives a substantially linear monotonically decreasing quantity of current 1810. The current 1810 is linearly decreased from the beginning time of the initialization t0 1820, through various other times, such as t1 1830 and t2 1840. The current is modulated between t2 1840 and t3 1850, in anticipation of a disturbance in the air bearing. The effects of the disturbance in the air bearing as shown in one example as a disturbance in the available torque between t2 240 in FIG. 2 and t3 250 in FIG. 2, disturbance in the R.P.M. between t2 340 in FIG. 3 and t3 350 in FIG. 3, and as disturbance in the drag between t2 440 in FIG. 4 and t3 450 in FIG. 4. The modulation of current between t2 1840 and t3 1850 solves the disturbances shown in FIGS. 2–4.
FIG. 19 is a chart 1900 of a relationship between available torque and time in a mass storage device using the present invention during initialization. In general, the quantity of available torque 1910 decreases during spin-up of the disc. The quantity of available torque 1910 decreases from the beginning time of the initialization t0 1920, through various other times, such as t1 1930, t2 1940, and t3 1950, until a target rotation speed is achieved at time t4 1960, after which, no torque is available when the quantity of current input to the motor is held constant, as shown in FIG. 18, to maintain the target rotation speed.
FIG. 20 is a chart 2000 of a relationship between rotation speed of the disc and time in a mass storage device using the present invention during initialization. In general, the rotation speed (RPM) 2010 increases during spin-up of the disc. The rotation speed 2010 increases from the beginning time of the initialization t0 2020, through various other times, such as t1 2030, t2 2040, and t3 2050, until a target rotation speed is achieved at time t4 2060. After the target rotation speed is achieved, the rotation speed 2010 is held substantially constant through a constant input of current, as shown in FIG. 18.
FIG. 21 is a chart 2100 of a relationship between drag and time in a mass storage device using the present invention during initialization. In general, drag 2110, decreases during spin-up of the disc. The drag 2110 generally decreases from the beginning time of the initialization t0 2120, through various other times, such as t1 2130, t2 2140, and t3 2150, until a rotation speed is achieved at time t4 2160. After the target rotation speed is achieved, the drag 2110 remains substantially constant through a constant input of current, as shown in FIG. 18.
FIG. 22 is an exploded view of one embodiment of a disc drive of the present invention, this embodiment showing one type of magnetic disc drive 2200 having a rotary actuator. The disc drive 2200 is one example of mass storage devices, such as compact disc (CDROM) devices, tape cartridge devices, digital versatile disc (DVD) or digital video disc (DVD) devices. Other embodiments include other configurations and data recording and/or reading technologies. The disc drive 2200 includes a housing or base 2212, and a cover 2214. The base 2212 and cover 2214 form a disc enclosure. Rotatably attached to the base 2212 on an actuator shaft 2218 is an actuator assembly 2220. The actuator assembly 2220 includes a comb-like structure 2222 having a plurality of arms 2223. Attached to the separate arms 2223 on the comb 2222, are load beams or load springs 2224. Load beams or load springs are also referred to as suspensions. Attached at the end of each load spring 2224 is a slider 2226, which carries a magnetic transducer 2250. In some embodiments, transducer 2250 includes an electromagnetic coil write head and a magneto-resistive read head. The slider 2226 with the transducer 2250 form what is often called the head. It should be noted that many sliders have one transducer 2250 and that is what is shown in the figures. It should also be noted that this invention is equally applicable to sliders having more than one transducer, such as what is referred to as an MR or magneto resistive head in which one transducer 2250 is generally used for reading and another is generally used for writing. On the end of the actuator assembly 2220 opposite the load springs 2224 and the sliders 2226 is a voice coil 2228.
FIG. 23 is a schematic view of an information handling systems 2300. Advantageously, the invention is well-suited for use in an information handling system 2300. The information handling system 2300 may also be called an electronic system or a computer system and includes a central processing unit, a memory and a system bus. The information handling system 2300 includes a central processing unit 2304, a random access memory 2332, and a system bus 2330 for communicatively coupling the central processing unit 2304 and the random access memory 2332. The information handling system 2300 includes a disc drive device. The information handling system 2300 may also include an input/output bus 2310 and several peripheral devices, such as 2312, 2314, 2316, 2318, 2320, and 2322, which may be attached to the input output bus 2310. Peripheral devices may include hard disc drives, magneto optical drives, floppy disc drives, monitors, keyboards and other such peripherals.
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U.S. Classification 318/560, 369/53.14, 369/53.13, 360/75, 318/638, 360/77.04, 369/47.44, G9B/19.046, 369/30.22, 388/902, 369/53.15, 388/815, 369/53.12, 369/44.32, 318/565, 388/806, 369/53.18, 369/53.42, 388/823