Abstract: According to one embodiment, in a disk device, a controller adjusts a correction value of a radial position of servo track according to a ratio between amplitude of a correction value spectrum of a radial position of the servo track at a first circumferential position and at a second circumferential position when positioning control of the head to a target data track is performed on a basis of servo information read from the servo track. At the first circumferential position, a relative speed of a change in the radial position of the servo track with respect to a radial position of the target data track becomes a first speed. At the second circumferential position, a relative speed of a change in the radial position of the servo track with respect to the radial position of the target data track becomes a second speed.

Abstract: In a disk drive that includes a magnetic head and a flexible printed circuit board (FPCB) coupled to an actuator for the magnetic head, a method of writing servo information includes: receiving a signal based on an electrical property of a material included in the FPCB, wherein the electrical property of the material changes as the actuator moves; determining a radial position of the magnetic head relative to a disk of the disk drive based on the signal; and controlling a radial velocity of the magnetic head relative to the disk of the disk drive based on the radial position.

Abstract: Generating a hard disk drive (HDD) data track repeatable runout (RRO) compensation value for a target track involves querying at least one RRO table for a closest track to the target track external servo target (EST) and identifying an ESTx corresponding to the closest track, computing a first absolute value of the difference between the EST and the ESTx, and responsive to the first absolute value being less than an approximation threshold, setting the RRO compensation value for the target track to the RRO compensation value for the closest track. Else, querying the RRO table(s) for each adjacent track to the target track, computing the difference between the ESTs for the adjacent tracks, and responsive to the second absolute value being less than an interpolation threshold, determining an RRO compensation value for the target track based on RRO compensation values corresponding to the adjacent tracks.

Abstract: An encoder includes a scale having a pattern to be detected, a detecting sensor outputting a signal corresponding to the pattern, a position calculator calculating a relative position between the scale and the detecting sensor based on the signal, a position data storage storing the calculated position data, and a position estimator estimating a relative position between the scale and the detecting sensor at a calculation-target time point based on the stored position data. The position estimator estimates the position at the calculation-target time point based on positions at first and second time points each preceding the calculation-target time point by a predetermined time. The position estimator processes position data in a first time width centered on the first time point and position data in a second time width centered on the second time point to calculate the positions at the first and second time points.

Abstract: A computing system may include a data access engine and a toolpath adjustment engine. The data access engine may be configured to access a computer-aided design (CAD) model of a part design and a computer-aided manufacturing (CAM) setup for the part design. The CAM setup may include a nominal toolpath specified through the CAD model for performing a finishing operation for the part design. The data access engine may also be configured to obtain 3-dimensional (3D) scan data for a physical part manufactured from the part design. The toolpath adjustment engine may be configured to extract, from the 3D scan data, a manufactured geometry of the physical part manufactured from the part design and generate an adjusted toolpath for the physical part to account for the manufactured geometry extracted from the 3D scan data.

Abstract: Systems, apparatuses, and methods for predictive memory access are described. Memory control circuitry instructs a memory array to read a data block from or write the data block to a location targeted by a memory access request, determines memory access information including a data value correlation parameter determined based on data bits used to indicate a raw data value in the data block and/or an inter-demand delay correlation parameter determined based on a demand time of the memory access request, predicts that read access to another location in the memory array will subsequently be demanded by another memory access request based on the data value correlation parameter and/or the inter-demand delay correlation parameter, and instructs the memory array to output another data block stored at the other location to a different memory level that provides faster data access speed before the other memory access request is received.

Abstract: A numerical controller, which can handle information on a use tool, calculates the shape of a workpiece being machined, based on an input machining program, shape information of the use tool, shape information of a unmachined workpiece, and a tool trajectory, and sets, as a movable range of the tool, a range in which the tool never contacts the workpiece being machined, based on the calculated shape of the workpiece being machined, if manual operation is performed during machining.

Abstract: A key based technique that targets obfuscation of critical circuit parameters of an analog circuit block by masking physical characteristics of a transistor (width and length) and the circuit parameters reliant upon these physical characteristics (i.e. circuit biasing conditions, phase noise profile, bandwidth, gain, noise figure, operating frequency, etc.). The proposed key based obfuscation technique targets the physical dimensions of the transistors used to set the optimal biasing conditions. The widths and/or lengths of a transistor are obfuscated and, based on an applied key sequence, provides a range of potential biasing points. Only when the correct key sequence is applied and certain transistor(s) are active, are the correct biasing conditions at the target node set.

Abstract: In a rail inspection system, a positional deviation can be detected with accuracy. The rail inspection system includes a first sensor unit which is disposed to face a rail for a vehicle, and includes at least one receiver coil and at least one oscillation coil which are arranged in an arrangement direction intersecting with a layout direction of the rail, an AC voltage source which applies AC voltage to the oscillation coil, and a displacement detection unit which detects a displacement between the rail and the first sensor unit based on an induced voltage of the receiver coil. The first sensor unit is configured such that, when the displacement is a first displacement, a first maximum value appears in the induced voltage, and when the displacement is a second displacement, a second maximum value of which a phase is reversed against the first maximum value appears in the induced voltage.

Abstract: An apparatus includes an inversion circuit configured to invert a data word, a first partial-inversion circuit configured to invert a first portion of the data word, a second partial-inversion circuit configured to invert a second portion of the data word, and an output selection circuit configured to compare: the data word, an output of the inversion circuit, an output of the first partial-inversion circuit, and an output of the second partial-inversion circuit with a prior data word, and to select an output according to respective numbers of changed bits from the prior data word.

Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.

Abstract: A method for identifying an error state in a brushless direct current motor. For the purposes of this identification, an angle deviation between a shaft angle and a control angle is calculated and used to identify error states on the basis of characteristic patterns. This also works, in particular, for slowly-rotating or stationary brushless direct current motors and allows a clear reduction in the calculation capacities required, compared to the prior art.

Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.

Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.

Abstract: A method of measuring feeding velocity of a web, on which a scale having pitches different from pitches of a mask are formed, is provided. The method includes: calculating a number of vibrations of a moiré image of light passing through the mask and the scale; calculating pitches of the scale of the fed web based on the calculated number of vibrations of the moiré image; averaging the pitches of the scale so that a change in a pitch between adjacent timings among the calculated pitches of the scale is minimized; extracting first signals corresponding to our phases for one pitch based on the averaged pitches of the scale; calculating two second signals for forming a Lissajous circle from the first signals; and calculating an angle of the Lissajous circle by the two second signals and then calculating the feeding velocity of the web by using the calculated angle.

Abstract: An apparatus for detecting speed of a motor is disclosed, the apparatus including an amplifier configured to amplify a two-phase sine-wave signal inputted from an encoder based on rotation of a motor; a first conversion unit configured to convert the two-phase sine-wave signal to a digital data; a second conversion unit configured to convert the two-phase sine-wave signal to a square-wave signal; a counter unit configured to accumulate by counting the square-wave signal; and a speed determination unit configured to determine a speed of the motor, by receiving the digital data from the first conversion unit and the accumulated count from the counter unit.

Abstract: Determining quality metrics of a magnetic tape recording medium. A production module that includes a write element that writes magnetic transitions to the magnetic tape is substantially in constant physical engagement with the magnetic tape. A supplemental module that includes one or more read elements periodically physically engages the magnetic tape, and the read elements generate an electrical signal corresponding to transitions written to the magnetic recording medium by a write element. A computer receives information representative of the electrical signal and determines if a quality metric of the magnetic recording medium derived from the electrical signal is within a defined range. If the quality metric is not within the defined range, a defined action is performed by the computer.

Abstract: A method of estimating the position of a rotor of an electric motor comprises producing an output signal indicative of motor position using a position sensor which comprises a detector and at least one encoder which rotates along with the rotor of the motor and includes a plurality of encoding regions, the output signal of the sensor varying in a stepwise fashion as the encoding regions move past the detector, and passing the output of the sensor through a smoothing algorithm to produce an estimated position signal, the algorithm being arranged to smooth the transition between the steps in the output of the sensor by causing the estimated position signal to lag behind the output of the sensor following a step change in the output of the sensor.

Abstract: A readhead control mechanism serves to control a readhead included in an optical encoder that measures a mechanical displacement between a fixed portion and a movable portion by reading out a gradation mark on a scale provided on the fixed portion, by using the readhead that is provided on the movable portion. The readhead mechanism includes a securing member that secures the readhead onto the movable portion, an actuator that is directly or indirectly secured onto the readhead to shift the readhead in an approaching direction or in a distancing direction, and an actuator controller that controls the actuator to maintain a constant distance between the readhead and the scale.

Abstract: A supplemental module that includes one or more read elements periodically engages a magnetic recording medium, and the read elements generate an electrical signal corresponding to transitions written to the magnetic recording medium by a write element. A computer receives information representative of the electrical signal and determines if a quality metric of the magnetic recording medium derived from the electrical signal is within a defined range. If the quality metric is not within the defined range, a defined action is performed by the computer.

Abstract: An optical probe is provided. The optical probe includes a lens extending along an axis between a first end and a second end. A spacer extends along the axis between a first end and a second end. The first end of the spacer is connected to the second end of the lens. A prism is connected to the second end of the spacer such that the prism is spaced apart from the lens by the spacer.

Abstract: The application manager 37 conducts “application signaling” when a first disc is replaced with a second disc. At this point, an application is continued if it is written in an application management table assigned to a Title played last on a first disc and also written in an application management table assigned to a Title to be played first on a second disc. On the other hand, an application is ended is it is written in the application management table assigned to the Title played last on the first disc but not written in the application management table assigned to the Title to be played first on the second disc.

Abstract: There is disclosed herein a method and apparatus for centering a disk on a spindle, a spinstand and a method of testing with a spinstand. The method of centering includes attaching the disk to the spindle with a stick-slip clamp. A vector is determined by which the centre of the disk is displaced from the spindle axis and the vector is aligned with a movably mounted piezo actuator. A voltage is then applied to the piezo actuator to cause the piezo actuator to apply an impulse to the edge of the disk to cause the disk to slip in the clamp and reduce the displacement of the disk.

Abstract: A method and system for determining a shape of a portion of an air-bearing surface (ABS) of a head residing on a slider are described. The ABS is configured to fly at a fly height from and with a velocity with respect to a disk during normal operating conditions. The method and system include driving at least one heater residing in the head while the slider is substantially at the normal operating conditions with respect to the disk and the fly height. The shape of the portion of the ABS changes in response to the heater(s) being driven. The method and system also include performing Doppler measurements on the slider while the heater is driven. The shape may then be determined based on the Doppler measurements.

Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.

Abstract: A hard disk drive includes a housing including a base member and a cover member, a spindle motor disposed in the housing, a data storage disk disposed on the spindle motor, an actuator disposed in the housing to move a read/write head to a position on the data storage disk, a clock signal providing unit disposed on the data storage disk to provide a clock signal of the data storage disk, a position signal providing unit disposed on the actuator to provide a position signal of the actuator, and first and second windows disposed in the housing to correspond to the clock signal providing unit and the position signal providing unit.

Abstract: Cross-track deviation of a writer from a predetermined track on a recording medium is detected. A write current is adjusted based on the cross-track deviation of the writer from the predetermined track. The adjusted write current is applied to the writer to compensate for the cross-track deviation of the writer from the predetermined track.

Abstract: A storage system includes a first buffer configured to store a first repeatable runout profile (RRP) for a sector of a rotating storage medium. A second buffer is configured to store a second RRP for the sector. A controller: controls a servo of the rotating storage medium based on the first RRP during a first revolution of the rotating storage medium; and learns the second RRP (i) while operating in a track-following mode, and (ii) during the first revolution. The controller ceases learning of the second RRP when one of (i) the controller is operating in a seek mode and (ii) the rotating storage medium is in an off-track state. Subsequent to the first revolution of the rotating storage medium and based on whether the learning of the second RRP was stopped during the first revolution, the controller replaces the first RRP with the second RRP in the first buffer.

Abstract: A method for producing a thin film magnetic head including a magnetoresistive effect element (MR element) that has a magnetic sensor multi-layered film with a polygonal shape such that a vertex angle faces an air bearing surface (ABS) and a tip of the vertex angle is cut when the magnetic sensor multi-layered film is viewed from an X-Y plane that is parallel to a plane of a lower shield electrode layer includes a step for stopping a lapping process by using a measurement point in which a resistance value is steeply increased while the lapping face is gradually approaching the vertex angle of polygonal shape by lapping from the ABS side. Therefore, an excellent effect in which an ultra narrow track width that exceeds limits of photolithography technology can be securely and constantly formed is obtained.

Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.

Abstract: Disclosed are a data storage apparatus, an assembling method thereof and an apparatus for generating a tracking position error signal capable of storing data using recording media formed with patterns for generating tracking position error signals to obviate errors that may be generated amidst storage of the data, wherein the patterns are formed for generating tracking position error signals on recording media before the recording media and storage are assembled to reduce the manufacturing cost and manufacturing process time.

Abstract: The application manager 37 conducts “application signaling” when a first disc is replaced with a second disc. At this point, an application is continued if it is written in an application management table assigned to a Title played last on a first disc and also written in an application management table assigned to a Title to be played first on a second disc. On the other hand, an application is ended is it is written in the application management table assigned to the Title played last on the first disc but not written in the application management table assigned to the Title to be played first on the second disc.

Abstract: According to one embodiment, a magnetic disk device includes a receiver, a storage module, a determining module, and a prescanner. The receiver receives a command from a host device. The storage module stores, with respect to each of divided areas formed by dividing the recording area of a recording medium into a plurality of areas, pre-scan control information indicating at least one of the receiving time and the number of receiving times. The receiving time indicates a time at which a write command is received. The number of receiving times indicates the number of times the write command is received within a predetermined period after the power is turned on. The determining module determines the order in which pre-scan is performed on the divided areas based on at least one of the receiving time and the number of receiving times. The prescanner pre-scans the divided areas in the determined order.

Abstract: A method of controlling the position of a read/write head relative to a disk in a test apparatus is disclosed. The test apparatus has a positioner for positioning the head. The positioner has a sensor to measure the actual position achieved by the positioner. The method includes generating a sensor signal measuring the actual position achieved by the positioner; generating a position error signal of the head relative to the disk detected at the head; high pass filtering the head position error signal and low pass filtering the sensor signal so that there is substantially no overlap in frequency between them; and, deriving a low frequency head error signal from the head position error signal corresponding to any drift of the head.

Abstract: Embodiments of mitigating the effects of disturbances of a disk drive are disclosed. One method includes sensing a position error signal of a transducer coupled to a surface of the disk drive, wherein the position error signal aids in control of an actuator of the disk drive. A first disturbance signal is generated by sensing a disturbance of a first sensor attached to the disk drive, wherein the first disturbance signal aids in control of the actuator. A second disturbance signal is generated by sensing a disturbance of a second sensor attached to the disk drive, wherein the second disturbance signal aids in control of the actuator. Effects of the disturbances on the position error signal are reduced by adaptively adjusting a gain of the first disturbance signal and a gain of the second disturbance signal.

Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.

Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.

Abstract: A rotation disturbance compensation control unit applies a compensation signal to a positioning control unit so as to cancel out rotation disturbance vibration components detected by using acceleration velocity sensors. At predetermined timing, a position error detection unit detects respective position errors of the case in which the rotation disturbance compensation control unit is turned on and the case in which it is turned off. A compensation control switching unit switches the rotation disturbance compensation control unit to be on if the position error of the case in which the compensation control of rotation disturbance is turned on is small and switches the compensation control switching unit to be off if the position error of the case in which the compensation control of rotation disturbance is turned off is small.

Abstract: A recording system for magnetic storage devices, including a beam column for generating a beam, a platform for moving a magnetic storage medium relative to the beam, and a signal generator for sequentially, or in a continuously alternating manner, deflecting the beam. In turn, the beam is directed according to displacement of dots on the extent of the magnetic storage medium such that dots of a plurality of dot groupings can be written to on the extent during a single pass of the beam column above the extent.

Abstract: A microactuator incorporated within an actuator assembly of a disk drive is used as a detection element for rapid off track events that may occur. Preferably, the microactuator employs one or more piezoelectric elements used for purposes of secondary actuation. Uncontrolled movement of the actuator across the disk results in the piezoelectric elements generating a voltage spike or signal that is analyzed to determine whether a rapid off track event has occurred. Rapid off track events are distinguished from other possible events, such as shock events. If a rapid off track event is detected, then remedial actions are taken to restore data integrity, to include executing restore commands such as rewriting selected data tracks. Dedicated piezoelectric elements may also be provided for detecting rapid off track events wherein these elements are not incorporated in the servo loop that controls positioning of the actuator.

Abstract: An air pressure sensor capable of measuring air pressure highly accurately with a simple configuration is provided. The sensor includes: a sealed case with a sealed space formed therein; a first thin plate member which constitutes at least a part of the wall of the sealed case and deforms to allow the capacity of the sealed space to vary corresponding to changes in the outside air pressure; a first PZT which contacts the first thin plate member to thereby detect the natural frequency thereof; and a second thin plate member which has the same vibration characteristics as those of the first thin plate member and is provided outside the sealed case while contacting it; and a second PZT which has the same temperature characteristics as those of the first PZT and contacts the second thin plate member to thereby detect the natural frequency thereof.

Abstract: A control system including a filter module generates a filtered disturbance signal based on a disturbance signal and a transfer function of the filter module. A set point adjustment module generates an adjusted set point signal based on a set point signal and the filtered disturbance signal. A servo control module generates an error signal based on the adjusted set point signal and a position feedback signal. A filter adjustment module generates a filter adjustment signal based on the disturbance signal and the error signal. The filter adjustment signal adjusts the transfer function.

Abstract: A disk drive is disclosed including a disk, an actuator arm, a head attached to a distal end of the actuator arm, a mechanical position sensor operable to generate a position signal representing a position of the head relative to the disk, and a voice coil motor for rotating the actuator arm about a pivot. The disk is rotated at a predetermined velocity, a control signal is generated in response to the position signal generated by the mechanical position sensor, and the control signal is applied to the voice coil motor in order to seek the head radially over the disk while writing a spiral track to the disk. The spiral track is then processed to maintain the head along a servo track while writing product servo sectors along the servo track.

Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.

Abstract: A sensing device for sensing installation position of a read head is assembled on the read head correspondingly to a scale and comprises at least three sensing elements and three signal generators. The three sensing elements are located on one end surface of the read head facing the scale to sense the distance between the read head and the scale. According to the different distance, the respective signal generators will send out different signals to inform the user if the read head is correctly installed, thus ensuring the precision of the installation, the sensing operation and movement of the read head.

Abstract: Disturbances to actuator control caused by external vibrations are corrected using feed-forward techniques that are selectively enabled or disabled based on signal values within a track follow loop. An increase in data integrity and reliability may be achieved by reducing off-track reads and writes caused by physical disturbances to disk drives during operation. Accelerometers detect external forces imparted on a disk and an acceleration feed-forward (AFF) signal is generated to compensate for disturbances to the location of a head caused by such external forces. Application of the AFF signal to an actuator may be based on whether signal values along the track follow loop exceed a certain threshold.

Abstract: Methods and systems for reducing read/write head track misregistration are described. According to one embodiment, a first signal is received from a first capacitive sensor that faces a surface of a disk associated with a disk drive. A second signal is received from a second capacitive sensor that faces the surface of the disk. A determination is made as to whether the disk is being moved along its axis of rotation or whether the disk is tilting. Read/write head track misregistration is reduced based on the determination of whether the disk drive is being moved along an axis of rotation or whether the disk is tilting.

Abstract: Disclosed are a data storage apparatus, an assembling method thereof and an apparatus for generating a tracking position error signal capable of storing data using recording media formed with patterns for generating tracking position error signals to obviate errors that may be generated amidst storage of the data, wherein the patterns are formed for generating tracking position error signals on recording media before the recording media and storage are assembled to reduce the manufacturing cost and manufacturing process time.

Abstract: A noise canceling system includes a signal generator module that generates a set point signal based on a desired position signal and a position feedback signal, a summation module that generates an output control signal based on the set point signal and a correction signal, and a filter module that generates the correction signal based on a disturbance signal and that minimizes a correlation between the disturbance signal and an error signal. The error signal represents a difference between the desired position signal and the position feedback signal.

Abstract: A head suspension assembly including a load beam having a rigid region, a mounting region on a proximal end of the load beam, and a flexure on a distal end of the load beam. The flexure has a read/write head attachment region for supporting a read/write head on the distal end of the load beam. Deformation of the head suspension assembly displaces the head attachment region. A strain transducer circuit that acts as a strain gauge is mounted on the head suspension assembly. The resistance of the transducer circuit varies with strain in the circuit, which, in turn, varies with displacement of the read/write head. The magnitude of resistance change of the transducer circuit indicates the magnitude of head off-neutral motion.