Abstract: An airflow outlet comprising at least a first plurality of airflow direction elements, a second plurality of airflow direction elements, and an actuation system is provided. Each of the respective first airflow direction elements and second airflow direction elements include a vane shaft and at least one vane element disposed along the vane shaft and integrally coupled thereto. The actuation system is configured to control the position of the vane elements of each of the airflow direction elements. The actuation system includes a drive element engaged with the driven element, which is further engaged with the vane shafts of each of the airflow direction elements. A rotation of the drive element causes a proportional rotation of the vane elements of the each of the airflow direction elements to an operating position, which defines an airflow direction through the airflow outlet.

Abstract: Provided is a vibration-proof structure capable of more effectively reducing rotational vibration of a rotating body during a cutting operation. According to a configuration of the structure, inside a main body of the rotating body, there are provided a plurality of shaft members arranged along a longitudinal direction of a rotation axis of the rotating body and at least one layer of multiple tubular members fitted over the shaft members and arranged coaxially with the rotation axis along the longitudinal direction of this rotation axis; and a boundary position between the shaft members adjacent each other in the longitudinal direction and a boundary position between the tubular members adjacent each other in the longitudinal direction are set as different positions along the longitudinal direction.

Abstract: According to some embodiments of the present invention, a cooperatively-controlled robot includes a robotic actuator assembly comprising a tool holder and a force sensor. The cooperatively-controlled robot further includes a control system adapted to communicate with the robotic actuator assembly and the force sensor, and an actuator in communication with the control system and mechanically coupled to a tool. The force sensor is configured to detect a vibrational force applied on the tool and send a signal to the control system based on the vibrational force. The control system is configured to receive the signal and determine a force to apply to the tool to damp the vibrational force. The control system then signals to the actuator to apply the determined force, and the actuator applies the determined force to actively damp a vibration of the tool.

Abstract: A servo control apparatus according to the present invention includes a speed command generator; a torque command generator; a speed detector; a speed control loop; a speed control loop gain setting unit; at least one filter for filtering a specific band of a torque command value; a sinusoidal disturbance input unit for performing a sinusoidal sweep on the speed control loop; a frequency characteristics calculator for estimating the gain and phase of speed control loop input and output signals; a resonance frequency detector; a filter adjuster for adjusting the filter in accordance with a resonance frequency; a gain adjuster; a sequence controller for online and automatically performing the detection of the resonance frequency, the adjustment of the speed control loop gain, and the adjustment of the filter; and an adjustment state display unit. The adjustment state display unit displays a stage and progress in the adjustment by the sequence controller.

Abstract: A vane cluster includes a split damped outer shroud and an inner shroud spaced from the split damped outer shroud with a multiple of stator vane airfoils that extend between the split damped outer shroud and the inner shroud.

Abstract: A vibration control wall structure, which is introducible into a wall part of a building, includes a wall frame, a vibration control wall body, and a vibration control damper for absorbing a vibration acting on a building. The vibration control wall body includes a plurality of face materials which are fixed to a frame material via a fastening member and are connected to each other in a width direction. A gap part is formed such that both side end portions of the vibration control wall body are separated from the wall frame so as to absorb displacement in an in-plane direction. The vibration acting on the building is damped by the vibration control damper having a long hole in a longitudinal width direction of the vibration control wall body. The vibration control wall body can relatively slide in the long hole in the longitudinal width direction.

Abstract: A gas spring system includes: a gas spring assembly including at least one gas damping passage; a reservoir member connected to the gas spring assembly, the gas spring assembly being in fluid communication with the reservoir member by way of the at least one gas damping passage; and a guide member coupled with the gas spring assembly, the guide member at least partially enclosing the reservoir member and being configured for sliding axially relative to the reservoir member.

Abstract: A centrifugal pendulum device includes a pendulum mass carrier, which is rotatable about a rotation axis, and at least one pendulum mass, which is supported on the pendulum mass carrier for movement along a track between end stops which are spaced from one another in circumferential direction in relation to the rotation axis. A spring device urges the pendulum mass in one of the end stops, when the rotation speed of the pendulum mass carrier drops below a limit rotation speed.

Abstract: A method for assembling a pendulum-type damping device (1) includes the steps of force-fitting a first end of the spacer (17) into an opening (26) of a first part (3a) of a pendulum mass (3). A support (2) is positioned so that the spacer (17) spans a corresponding opening of the support (2). A roller is positioned between the spacer (17) and the edge of the opening of the support (2). The second end (17b) of the spacer (17) is force fit into an opening (26) of a second part (3b) of the mass (3).

Abstract: The present invention provides a vibration reduction apparatus which reduces a vibration of a target object supported on a base, comprising a first object supported by a first elastic member on the base, a second object supported by a second elastic member on the first object, a detection unit including a sensor having a first electrode provided on the first object and a second electrode provided on the second object, and a processor configured to obtain a distance between the first electrode and the second electrode using the sensor, a first driving unit configured to drive the first object, a first control unit configured to control the distance between the first electrode and the second electrode constant based on a detection result, wherein the second electrode and the processor are electrically connected to each other via the second elastic member.

Abstract: An apparatus for controlling an actuator in a camera module is provided. The apparatus includes a position controller for producing a control voltage to move a lens of the camera module, a hall sensor for detecting an amount of change in magnetic lines of force generated by a magnet as a hall voltage, a voice coil motor for moving the lens according to a current applied thereto, and a current controller for using a voltage applied to the voice coil motor to detect an interference voltage created by the current applied to the voice coil motor, for generating an interference-eliminated hall voltage by removing the interference voltage from the hall voltage, and for controlling the current applied to the voice coil motor based on the control voltage and the interference-eliminated hall voltage.

Abstract: Provided is a vibration control device, which enables the vibrations of a vibrating body, such as a rotary machine, to automatically be suppressed, without installing a vibration detection sensor on the vibration control device or vibrating body, and without controlling the rotational speed or phase of the vibration control device. The vibration control device (1), which is installed on a vibrating body (2) and controls the vibrations of the vibrating body (2), comprises a rotating shaft (11), a mass body (12) that is fixed to the rotating shaft (11), and an activation apparatus (13) that adds the power of a rotational motion, which is centered on the rotating shaft (11), to the mass body (12).

Abstract: A damping system (10) having a rotation axis (X) and comprising at least: one first flyweight (14) and one second flyweight (14) able to oscillate with respect to a support member (12), and at least one device (20) for guiding the first and second flyweights (14) with respect to the support member (12), having at least one bearing element (22) able to interact with a pair of opposite tracks, respectively a first guidance track (24) and a second guidance track (26) that is carried by the support member (12), wherein the first guidance track (24) is carried by said connecting means (16).

Abstract: A system, including methods and apparatus, of tuning a mass-damping apparatus to reduce dynamics forces on a wind tunnel model during wind tunnel testing. The mass-damping apparatus is coupled to a wind tunnel model and may comprise first and second pressure chambers containing a gas, a mass configured to move back and forth between the pressure chambers in a substantially airtight manner and thereby to alter gas pressure within each pressure chamber, at least one spring configured to exert a position-dependent force upon the mass, and a passageway configured to allow the gas to pass between the chambers.

Abstract: A vibration dampener, including, a first beam comprising a first mounting end portion and a first peripheral end portion, wherein the first peripheral end portion comprises a tunable mass, and the first beam is configured to vibrate in tune with a vibrational frequency of a structure supporting the first beam at the first mounting end portion, a second beam comprising a second mounting end portion and a second peripheral end portion, wherein the second peripheral end portion comprises a ring disposed about the first beam, and a viscoelastic material disposed between the first beam and the ring, wherein the viscoelastic material is configured to dampen vibrational energy as the first beam vibrates toward the ring until the viscoelastic material becomes compressed between the first beam and the ring during the course of the impact.

Abstract: A friction damper includes a base body; a support secured to an elongated member of the base body and having a through hole; a rod which extends in such a manner as to pass through the through hole of the support and is movable in an axial direction with respect to the support; a friction member which has a hollow cylindrical portion interposed between the support and a main body portion of the rod in the through hole of the support, and which is fixed immovably with respect to the relative movement of the rod in the axial direction with respect to the base body; and a tightening structure provided for the support so as to tighten the hollow cylindrical portion of the friction member onto the main body portion of the rod.

Abstract: A vehicle suspension and wheel damper using anti-causal filtering. Information from in front of a wheel or information about an operating condition of a vehicle is used to anti-causally determine a response of an active suspension associated with the wheel.

Abstract: An EPDM composition for a torsional damper. The EPDM composition is made of (a) an EPDM polymer, (b) liquid polyolefin oligomer, and (c) carbon black, the EPDM composition containing 100 parts by weight of EPDM polymer that is the EPDM polymer of (a) having a propylene content of 35 to 50 wt % in the total amount of ethylene and propylene, 5 to 30 parts by weight of liquid polyolefin oligomer that is the liquid polyolefin oligomer of (b) having a number average molecular weight Mn within a range of 3,000 to 4,000, and 10 to 120 parts by weight of carbon black that is the carbon black of (c) having a nitrogen adsorption specific surface area within a range of 100 to 150 m2/g, an iodine adsorption within a range of 110 to 160 mg/g, and a DBP oil absorption within a range of 70 to 135 cm3/100 g.

Abstract: An illustrative embodiment of a damper for use with rotary machinery may include a damper mass connected to an electronics housing via one or more piezo elements. The illustrative embodiment of the damper may include one or more electrical components wherein the electrical components, piezo elements, and/or damper mass may be tuned such that the damper is configured with an electrical resonance frequency corresponding to a mechanical resonance frequency present in a component of the rotary machinery. The piezo elements may be extension/retraction type or bending type, and they may have any orientation with respect to the rotational axis of the rotary machinery depending on the specific embodiment and/or application of the damper.

Abstract: A method for vibration damping of at least one blade of a turbomachine, wherein initially at least one damping element is arranged on the blade such that it can move in the axial direction, employs a damping element having a larger permeability constant than the blade (?rD>?rB), and then a magnetic field acting in the radial direction is generated at least temporarily during rotation of a rotor hub of the turbomachine in order to adjust the mass of the damping element in real time. A damping device includes, for example, a ferromagnetic damping element as well as a magnetic field source, and a turbomachine.

Abstract: An arrangement actuates an element in a microlithographic projection exposure apparatus. The arrangement includes first and second actuators and first and second mechanical couplings. The first and second actuators are coupled to the element via corresponding ones of the first and second mechanical couplings for applying respective forces to the element which is regulatable in at least one degree of freedom. The first and second actuators have first and second actuator masses, respectively, and the first actuator mass and the first mechanical coupling conjointly define a first mass-spring system operating as a first low-pass filter. The second actuator mass and the second mechanical coupling conjointly define a second mass-spring system operating as a second low-pass filter. The first and second mass-spring systems have first and second natural frequencies deviating from each other by a maximum deviation equal to 10% of the largest of the first and second natural frequencies.

Abstract: A tuned mass tool holder having an axis of rotation has a mass that can be varied. The distribution of the tool holder mass can be adjusted along the axis of rotation, the center of gravity of the tool holder can be moved along the axis of rotation, and the moment of inertia of the tool holder can be changed relative to the holder-spindle interface.

Abstract: An apparatus includes an external input device that allows setting of the amount of runout and the phase of each cutting edge, a computation device that acquires the rotational phase of a tool and that computes the angular velocity and the phase of vibration of two, X-axis and Y-axis, feed shafts on the basis of the input amount of runout and angular velocity of each cutting edge to generate a feed shaft control signal, and a numerical control device that controls feed in the X-axis and the Y-axis directions. The numerical control device relatively vibrates a workpiece in synchronization with the angular velocity of the tool on the basis of the results of computation performed by the computation device.

Abstract: A loudspeaker system, and a method and device for actuating a loudspeaker, using a loudspeaker element connected to a memory metal part and provided in a portable electronic device; and a power source unit configured to supply power to the memory metal part, wherein, when power is supplied to the memory metal part, the memory metal part is configured to exert a force on the loudspeaker element to actuate it.

Abstract: A touch panel support structure that can transfer vibration of a touch panel to the operator even though a transparent protective plate is in tight contact with the surface of a case is provided. A rectangular touch panel is sandwiched at four corners between the transparent protective plate that is fixedly attached to the case near the four corners and backside support members so that the four corners act as the nodes of vibration. The antinode of waveform of vibration is located in an input operation area inside the four corners so that the touch panel can vibrate with a certain amplitude together with the transparent protective plate that covers the input operation area, even though the touch panel is fixed to the frame-like case along its periphery via the transparent protective plate, and thus vibration can be transferred to the operator.

Abstract: Method and system for unspinning a payload ejected from a spinning artillery projectile where the projectile is loaded with a cargo holding the payload and a payload unspinning device. The cargo is ejected from the projectile and the payload unspinning device is operated. The cargo includes a parachute and a shroud which covers the folded parachute and at least a portion of the payload. The payload unspinning device includes at least two yo-yo cords. Ejection of the cargo is followed sequentially by unwinding of the at least two yo-yo cords, liberation of the shroud, deployment of the parachute and stabilization of the payload.

Abstract: An E clutch hub assembly for the Ford 6R140 transmission, that reduces the squawk noise that occurs during the 3-4 upshift. A clutch hub has a lower pressure washer onto which is stacked a damper hub having radially located lube holes to direct lube to the E clutch plates. An upper pressure washer is stacked onto the damper hub while a pressure plate, seated within a snap ring rove machined into the hub, applies pressure onto the two pressure washers which help absorb the squawk noise. A waved spring holds the entire assembly within the hub.

Abstract: Centrifugal pendulum device including pendulum masses arranged on axial sides of a pendulum mass support rotatable about an axis of rotation to form a pendulum mass pair. To form the mass pair, the masses are fastened to each other by means of a fastener passing through a cutout in the mass support. The mass pair is pivotable relative to the mass support due to a rolling element arranged to roll in a recess of the mass support and of the mass. In a section axially covering the recess of the mass support, the rolling element has a first outer diameter. In a section axially covering the recess of the pendulum mass, the rolling element has a second outer diameter. The rolling element further comprises a section axially located between the first and second diameters and has a third diameter, which is smaller than or equal to the first outer diameter.

Abstract: A vibration damping mechanism allows increase of an absorption amount of vibration energy, with less possibilities of increase in the manufacture cost of a vibration damping weight and of reduction in the strength of a shaft section. Within a cylindrical hollow portion formed inside the shaft section, there are accommodated a plurality of weight members divided from each other along the circumferential direction about the axis of the hollow portion. An urging member is provided for urging the weight members toward the axis such that dividing faces of adjacent weight members are brought into surface contact with each other.

Abstract: A torsional vibration damping arrangement comprises an input region to be driven in rotation around an axis of rotation and an output region and a first torque transmission path and parallel thereto a second torque transmission path, both of which proceed from the input region, and a coupling arrangement for superposing the torques conducted via the torque transmission paths, which coupling arrangement communicates with the output region, a phase shifter arrangement for the first torque transmission path for generating a phase shift of rotational irregularities conducted via the first torque transmission path relative to rotational irregularities conducted via the second torque transmission path, and a pendulum mass in the phase shifter arrangement and/or in the coupling arrangement.

Abstract: The invention relates to a vibration absorber for damping mechanical vibrations of a structure capable of vibration at least in some portions. The vibration absorber comprises at least two rod-shaped vibrating elements, which each have a longitudinal axis, and a support module. The support module comprises at least two non-parallel support plates and an attachment device. In this case, for the purpose of attaching the vibration absorber to the structure, the attachment device is constructed in such a way that mechanical vibrations of the structure can be passed into at least a first of the support plates. The support plates are interconnected in such a way that the mechanical vibrations can be transferred from the first support plate to a second of the support plates. A first vibrating element is coupled at a first position along the longitudinal axis of the first vibrating element to the first support plate.

Abstract: A vehicular antivibration device includes a torque rod and an actuator. The torque rod is connected at a first end to a vehicle body and connected at a second end to a vibration source. The actuator is disposed between the first end and the second end of the torque rod, includes an inertia mass supported on the torque rod, and causes the inertia mass to reciprocate in the axial direction of the torque rod. The actuator includes a coil, a magnetic core, a permanent magnet and a heat-conducting member. The magnetic core forms magnetic paths for the coil, and the coil is wound around the outer periphery of the magnetic core. The permanent magnet faces the inertia mass and is disposed on the magnetic core. The heat-conducting member is disposed so as to contact the coil and the torque rod.

Abstract: A system for damping oscillations in a structure provides two masses that can be controlled to rotate at the frequency of oscillation of the structure and in opposite directions about axes of rotation transverse to the direction of the oscillations. The masses have individually controllable moments of inertia, and when their moments of inertia are equal a harmonic linear force is generated. The phases of the rotating masses can be individually controlled whereby the direction of the resulting harmonic linear force can be controlled. The moments of inertia can be controlled by shifting their centers of gravity relative to the respective axes of rotation.

Abstract: A vibration control actuator includes a housing having a length between ends and a rotatable shaft located in the housing and extending along a housing length and which rotates about a shaft axis substantially parallel to the length. An inertia wheel assembly is operably connected to the rotatable shaft and configured to rotate therewith about the shaft axis. The inertia wheel assembly is in frictional contact with an inner wall of the housing and translatable to travel within the housing between the ends along at least a portion of the shaft axis.

Abstract: A Tuned Mass Damper (TMD) for damping oscillations of a hanging vertical pump structure includes a removable mass symmetrically configured within the pump structure diameter and supported by a mechanism which provides damped mobility relative to the pump structure so as to absorb and dampen pump vibrations and oscillations. The TMD mass is easily removable before tipping of the pump between horizontal and vertical orientations during maintenance. In some embodiments, the TMD mass comprises fluid pumped by the pump to fully or partially fill a housing, the fluid being gravitationally drained therefrom when the pump is not operating. In other embodiments the TMD mass is supplied by removable solid weights. Damped mobility is provided by springs damped by mechanical or fluid friction, or by obstructed movement of fluid within a partially filled housing. In embodiments, the TMD mass is at least 5% of the total mass of the pump structure.

Abstract: A damper having an elastic body formed from a cross-linking product of an EPDM composition, which comprises (a) 100 parts by weight of at least one kind of EPDM, whose propylene content in sum total of ethylene and propylene in the copolymerization rubber is 35-50 wt. %, the EPDM having a Mooney viscosity (ML100) of not less than 40, (b) 5-50 parts by weight of ?-olefin oligomer, which is a polymer of ?-olefin represented by the general formula, CH2CHR, where R is an alkyl group having 3-12 carbon atoms, with a number average molecular weight Mn of 300-1,400 and (c) 1-10 parts by weight of an organic peroxide cross-linking agent.

Abstract: The table on which a workpiece is put can travel on a guide rail mechanism relative to a working head with a cutting tool mounted thereon. The table is connected through a nut to a ball screw part to move in an axial direction thereof as the ball screw part rotates. One end of the ball screw part is supported by a bearing and the other end is connected to a servomotor to be rotationally driven. A hollow part is provided in the table to receive therein a damper mechanism part, which comprises a spring, a damper, and a weight, the table and the weight being arranged to enable traveling separately on guide rails. Thereby, even when the workpiece is heavy, the weight can move relative to the table to effectively damp vibrations of the table in a feed direction.

Abstract: A method for assembling a pendulum-type damping device (1) includes the steps of force-fitting a first end of the spacer (17) into an opening (26) of a first part (3a) of a pendulum mass (3). A support (2) is positioned so that the spacer (17) spans a corresponding opening of the support (2). A roller is positioned between the spacer (17) and the edge of the opening of the support (2). The second end (17b) of the spacer (17) is force fit into an opening (26) of a second part (3b) of the mass (3).

Abstract: Provided is a vehicle-mounted active vibration reducing device wherein vibrations in a plurality of directions are reduced by a single dynamic damper. Since an actuator is attached so as to be supported by an elastic member attached to a bracket, the actuator can be used as a mass of a dynamic damper. The moving directions of the actuator are the forward and rearward directions, and are different from the moving directions of the dynamic damper using the actuator as a mass, i.e., the upward and downward directions. Accordingly, vibrations can be controlled in the forward and rearward directions which correspond to the moving directions of the actuator as well as the upward and downward directions which correspond to the moving directions of the dynamic damper.

Abstract: A centrifugal pendulum vibration absorber (CPVA) for absorbing torsional vibration created by operation of an engine includes a plurality of pendulums moveable with respect to a rotatable shaft. The pendulums are connected to the rotatable shaft by a plurality of pins that extend through apertures in the pendulum. The pendulums each move along a path defined by various drive line or powertrain parameters and characteristics. The path is implemented by contouring an active section of the apertures that engage the pins.

Abstract: An assembly for dampening vibration movement between a cylinder and a concentric duct, where the cylinder is positioned radially inside the duct, includes a damper attached to the duct. The damper includes a housing attached to the duct, a contact member positioned at least partially inside the housing and having a contact surface adjacent an outer surface of the cylinder, and a cap threadedly engaged with the housing for applying a load on the contact member in a direction toward the cylinder.

Abstract: A vibration damping device which can improve a vibration damping performance of a damper having a chamber holding a rolling member. The vibration damping device is applied to a power transmission unit having an input side rotary member that transmits a power to an elastic member and an output rotary member that is rotated by the power transmitted from the elastic member. In order to damp vibrations of the output rotary member, the vibration damping device is comprised of a holding chamber rotated integrally with the input side rotary member and a rolling member held in the holding chamber in a manner to rotate in a same direction as the output side rotary member while being allowed to rotate relatively therewith.

Abstract: Actuator arrangement with an actuator (8), a reference mass (22), a spring (24) and a first sensor (26; 42, 43; 32, 36). The actuator (8) applies a force between a first object (2) relative to a second object (16; 54). The reference mass (22) is, in use, supported by a third object (16; 56) by means of the spring (24). The first sensor (26; 42, 43; 32, 36) generates a first distance signal that depends on a first distance (z2; z5,z6; z3,z4) between the reference mass (22) and the first object (2) and is provided to a controller (6) to actuate the actuator (8).

Abstract: A centrifugal-pendulum vibration absorbing device, including a member attached coaxially with a rotary element; and mass bodies swingably coupled to the support member and disposed adjacent to each other in a circumferential direction. The mass bodies are configured such that when a first mass body, which is one of two mass bodies disposed adjacent to each other, and a second mass body, which is the other of the two mass bodies, move with respect to the support member so as to approach each other, the first mass body and the second mass body overlap each other as seen from an axial direction of the rotary element.

Abstract: A vibration attenuator for an aircraft has at least one weight mounted in a rotating system of a rotor hub of the aircraft, each weight being rotatable about an axis of rotation of the hub relative to the hub and to each other weight. Drive means are provided for rotating each weight about the axis of rotation at a selected speed for creating oscillatory shear forces that oppose and attenuate rotor-induced vibrations having a selected frequency. A vertically oriented vibration attenuator is configured to oppose and attenuate vertical rotor induced oscillatory forces that would otherwise travel vertical down the rotor mast and into the airframe. A vibration attenuator having weights rotating about separate axes offset from each other.

Abstract: A torsional vibration damping device that can ensure a space for allowing a mass body to make reciprocating movements and can improve the vibration damping performance is provided. A torsional vibration damping device in which a mass body is attached to a rotating body by two support pins includes two first hollow portions which are formed in the rotating body at positions corresponding to the respective support pins and into which the respective support pins are inserted, and two second hollow portions which are formed in the mass body at positions opposed to the respective first hollow portions and into which the respective support pins are inserted. Outer sides of inner peripheral edges of the respective first hollow portions in a radial direction of the rotating body serve as guide faces. Inner sides of inner peripheral edges of the respective second hollow portions in the radial direction of the rotating body serve as attachment faces.

Abstract: An active damping system for use in connection with a vibration isolation system includes an intermediate mass between a base and an isolated payload. The intermediate mass is supported by at least one support element which also supports at least substantially all of the static forces of the isolated payload. An actuator dampens and isolates dynamic forces acting on the intermediate mass from the isolated payload. The active damping system also includes a payload support element and a passive damping element, both of which are coupled at one end to the payload platform and at an opposite end to the intermediate mass. A sensor is affixed to the intermediate mass to generate a feedback signal to a processor coupled to the actuator.

Abstract: A damper for decreasing a piping vibration capable of enhancing the efficiency in decreasing the piping vibration and adjusting the weight of a weight portion according to the type of the compressor and the shape of the pipe applied to the compressor by separating a fixed portion from a weight portion such that the fixed portion makes a direct contact with a pipe and the weight portion has an interval from the pipe without making a direct contact with the pipe, in which the damper installed on the pipe to decrease the vibration includes a fixation part provided with a coupling hole formed therein to be coupled to the pipe, and coupled and fixed to the pipe such that the coupling hole makes contact with an outer circumferential surface of the pipe, and a weight part connected to the fixation part.

Abstract: A system for reducing vibration in a wind turbine includes a mass structure having at least one hole extending therethrough; a rod having a top threaded portion, an upper level stop disposed on or below the threaded portion, and a fixed lower level stop disposed below the upper level stop. The mass structure has a designed weight and shape that, in combination with the adjustable axial distance between the upper level stop and the lower level stop, is designed to provide a properly tuned system for a particular frequency. A base having an aperture designed for receipt of the lower level stop therein is configured for attachment to a component of the wind turbine.

Abstract: Vibration in a mechanical system driven by a motor connected to a load is reduced by providing an angular position and an angular velocity of the motor to a linear feedback term and to a nonlinear feedback term. Outputs of the linear feedback term and the nonlinear feed term, and an optimal feedforward term determined off-line are summed to produce a summed signal, which is fed back to control a torque of the motor.