US4283957A — Torsional exciter for a rotating structure

Claim 1

Independent Claim 195 words

An exciter for applying torque to a rotating structure, comprising: a rotary hydraulic actuator including a first element and a second element, said second element being rotatable relative to said first element; means for securing one of said first and second elements to said rotating structure; an inertial mass mounted on the other of said first and second elements; a hydraulic power supply for supplying pressurized fluid; and electrohydraulic means for controlling said actuator, said electrohydraulic means including: (a) a torque setpoint circuit for selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to said rotating structure; (b) means for producing a torque feedback signal dependent on the actual torque applied to said rotating structure; (c) a controller responsive to said command and feedback signals for producing a control signal; and (d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator oscillates said inertial mass with respect to said rotating structure at said desired amplitude and frequency; whereby a controlled dynamic torsional force is applied to said rotating structure.

Claim 2

Dependent Claim 195 words

An exciter for applying torque to a rotating structure, comprising: a rotary hydraulic actuator including a first element and a second element, said second element being rotatable relative to said first element; means for securing one of said first and second elements to said rotating structure; an inertial mass mounted on the other of said first and second elements; a hydraulic power supply for supplying pressurized fluid; and electrohydraulic means for controlling said actuator, said electrohydraulic means including: (a) a torque setpoint circuit for selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to said rotating structure; (b) means for producing a torque feedback signal dependent on the actual torque applied to said rotating structure; (c) a controller responsive to said command and feedback signals for producing a control signal; and (d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator oscillates said inertial mass with respect to said rotating structure at said desired amplitude and frequency; whereby a controlled dynamic torsional force is applied to said rotating structure.

Claim 3

Dependent Claim 107 words

The exciter of claim 1 wherein said electrohydraulic means further includes: a position setpoint circuit for selectively producing a position command signal to set a desired midpoint of the arc through which said inertial mass oscillates; and means for producing a position feedback signal dependent on the average angular position of said inertial mass relative to said rotating structure as said inertial mass oscillates; and wherein said controller is responsive to said position command and position feedback signals for producing a position error signal and for modifying said control signal in response to said position error signal; whereby said inertial mass oscillates symmetrically about said desired midpoint.

Claim 4

Dependent Claim 30 words

The exciter of claim 2 wherein said torque setpoint circuit is adjustable for producing a random variation in the amplitude or frequency of the torque applied to said rotating structure.

Claim 5

Dependent Claim 145 words

The exciter of claim 2 wherein said first actuator element is a housing and said second actuator element is a driveshaft and wherein said inertial mass is a disc having arcuate slots, said disc being mounted on said driveshaft, said exciter further including a mounting plate secured to said housing for mounting said actuator on said rotating structure, said mounting plate being secured to said housing by mounting means including spacers extending through said slots and disposed between said housing and said disc, and wherein said means for producing a position feedback signal includes a first pin fixed to said housing and a second pin fixed to said disc, a first detector for sensing said first pin and a second detector for sensing said second pin and an interface circuit for producing an average position signal, said average position signal constituting said position feedback signal.

Claim 6

Dependent Claim 30 words

The exciter of claim 4 wherein said torque setpoint circuit is adjustable for producing a random variation in the amplitude or frequency of the torque applied to said rotating structure.

Claim 7

Dependent Claim 54 words

The exciter of claim 1 or 2 wherein said first actuator element is a housing and said second actuator element is a driveshaft and wherein said inertial mass is a disc mounted on said driveshaft, said exciter further including a mounting plate secured to said housing for mounting said housing on said rotating structure.

Claim 8

Dependent Claim 30 words

The exciter of claim 6 wherein said torque setpoint circuit is adjustable for producing a random variation in the amplitude or frequency of the torque applied to said rotating structure.

Claim 9

Dependent Claim 62 words

The exciter of claim 1 wherein said actuator further includes a first chamber and a second chamber and wherein said means for producing a torque feedback signal includes first and second pressure transducers and an interface circuit for producing a differential pressure signal dependent on the actual torque applied to said rotating structure, said differential pressure signal constituting said torque feedback signal.

Claim 10

Dependent Claim 30 words

The exciter of claim 8 wherein said torque setpoint circuit is adjustable for producing a random variation in the amplitude or frequency of the torque applied to said rotating structure.

Claim 11

Dependent Claim 30 words

The exciter of claim 1 wherein said torque setpoint circuit is adjustable for producing a random variation in the amplitude or frequency of the torque applied to said rotating structure.

Claim 12

Independent Claim 231 words

An apparatus for mechanically testing a rotating structure to determine the response, natural modes of vibration or fatigue life of the rotating structure in the presence of dynamic torsional excitation, comprising: a rotary structure to be tested; a motor; a drivetrain interconnecting said rotary structure and motor; said motor being selectively energizable for activating said drivetrain to rotate said rotary structure; a rotary hydraulic actuator including a housing and a driveshaft, said driveshaft being rotatable relative to said housing; means for securing said housing to said rotating structure; an inertial mass mounted on said driveshaft; a hydraulic power supply for supplying pressurized fluid; and electrohydraulic means for controlling said actuator, said electrohydraulic means including: (a) a torque setpoint circuit for selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to said rotating structure; (b) means for producing a torque feedback signal dependent on the actual torque applied to said rotating structure; (c) a controller responsive to said command and feedback signals for producing a control signal; and (d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator oscillates said inertial mass with respect to said rotating structure at said desired amplitude and frequency; whereby a controlled dynamic torsional force is applied to said rotating structure.

Claim 13

Independent Claim 231 words

An apparatus for mechanically testing a rotating structure to determine the response, natural modes of vibration or fatigue life of the rotating structure in the presence of dynamic torsional excitation, comprising: a rotary structure to be tested; a motor; a drivetrain interconnecting said rotary structure and motor; said motor being selectively energizable for activating said drivetrain to rotate said rotary structure; a rotary hydraulic actuator including a housing and a driveshaft, said driveshaft being rotatable relative to said housing; means for securing said housing to said rotating structure; an inertial mass mounted on said driveshaft; a hydraulic power supply for supplying pressurized fluid; and electrohydraulic means for controlling said actuator, said electrohydraulic means including: (a) a torque setpoint circuit for selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to said rotating structure; (b) means for producing a torque feedback signal dependent on the actual torque applied to said rotating structure; (c) a controller responsive to said command and feedback signals for producing a control signal; and (d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator oscillates said inertial mass with respect to said rotating structure at said desired amplitude and frequency; whereby a controlled dynamic torsional force is applied to said rotating structure.

Claim 14

Dependent Claim 103 words

The apparatus of claim 11 further including: a position setpoint circuit for selectively producing a position command signal to set a desired midpoint of the arc through which said inertial mass oscillates; and means for producing a position feedback signal dependent on the average angular position of said inertial mass relative to said rotating structure as said inertial mass oscillates; and wherein said controller is responsive to said position command and position feedback signals for producing a position error signal and for modifying said control signal in response to said position error signal; whereby said inertial mass oscillates symmetrically about said desired midpoint.

Claim 15

Independent Claim 156 words

A method for applying torque to a rotating structure, including the steps of: securing one element of a rotary hydraulic actuator to the rotating structure; mounting an inertial mass on a second element of the actuator; providing a supply of pressurized fluid; and controlling the actuator for oscillating the second element with respect to the first element by (a) selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to the rotating structure; (b) producing a torque feedback signal dependent on the actual torque applied to the rotating structure; (c) producing a control signal in response to the command and feedback signals, and (d) controlling the supply of pressurized fluid to the actuator in response to the control signal such that the actuator oscillates the inertial mass with respect to the rotating structure at the desired amplitude and frequency; thereby applying a controlled dynamic torsional force to the rotating structure.

Claim 16

Independent Claim 156 words

A method for applying torque to a rotating structure, including the steps of: securing one element of a rotary hydraulic actuator to the rotating structure; mounting an inertial mass on a second element of the actuator; providing a supply of pressurized fluid; and controlling the actuator for oscillating the second element with respect to the first element by (a) selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to the rotating structure; (b) producing a torque feedback signal dependent on the actual torque applied to the rotating structure; (c) producing a control signal in response to the command and feedback signals, and (d) controlling the supply of pressurized fluid to the actuator in response to the control signal such that the actuator oscillates the inertial mass with respect to the rotating structure at the desired amplitude and frequency; thereby applying a controlled dynamic torsional force to the rotating structure.

Claim 17

Dependent Claim 95 words

The method of claim 13 further including the steps of: selectively producing a position command signal to set a desired midpoint of the arc through which the inertial mass oscillates; producing a position feedback signal dependent on the average angular position of the inertial mass with respect to the rotating structure as the inertial mass oscillates; producing a position error signal in response to the position command and position feedback signals; and modifying the control signal in response to the position error signal; thereby causing the inertial mass to oscillate symmetrically about the desired midpoint.

Claim 18

Independent Claim 207 words

A method for mechanically testing a rotating structure to determine the response, natural modes of vibration or fatigue life of the rotating structure in the presence of dynamic torsional excitation, including the steps of: rotatably mounting a rotary structure; interconnecting the rotary structure to a motor by means of a drivetrain; securing the housing of a rotary hydraulic actuator having a driveshaft to the rotary structure; mounting an inertial mass on the driveshaft of the actuator; selectively energizing the motor for activating the drivetrain to rotate the rotary structure; providing a supply of pressurized fluid; and controlling the actuator for oscillating the driveshaft with respect to the housing by (a) selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to the rotating structure; (b) producing a torque feedback signal dependent on the actual torque applied to the rotating structure; (c) producing a control signal in response to the command and feedback signals; and (d) controlling the supply of pressurized fluid to the actuator in response to the control signal such that the actuator oscillates the inertial mass with respect to the rotating structure at the desired amplitude and frequency; thereby applying a controlled dynamic torsional force to the rotating structure.

Claim 19

Independent Claim 207 words

A method for mechanically testing a rotating structure to determine the response, natural modes of vibration or fatigue life of the rotating structure in the presence of dynamic torsional excitation, including the steps of: rotatably mounting a rotary structure; interconnecting the rotary structure to a motor by means of a drivetrain; securing the housing of a rotary hydraulic actuator having a driveshaft to the rotary structure; mounting an inertial mass on the driveshaft of the actuator; selectively energizing the motor for activating the drivetrain to rotate the rotary structure; providing a supply of pressurized fluid; and controlling the actuator for oscillating the driveshaft with respect to the housing by (a) selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to the rotating structure; (b) producing a torque feedback signal dependent on the actual torque applied to the rotating structure; (c) producing a control signal in response to the command and feedback signals; and (d) controlling the supply of pressurized fluid to the actuator in response to the control signal such that the actuator oscillates the inertial mass with respect to the rotating structure at the desired amplitude and frequency; thereby applying a controlled dynamic torsional force to the rotating structure.

Claim 20

Dependent Claim 94 words

The method of claim 15 further including the steps of: selectively producing a position command signal to set a desired midpoint of the arc through which the inertial mass oscillates; producing a position feedback signal dependent on the average angular position of the inertial mass relative to the rotating structure as the inertial mass oscillates; producing a position error signal in response to the position command and position feedback signals; and modifying the control signal in response to the position error signal; thereby causing the inertial mass to oscillate symmetrically about the desired midpoint.

Claim 21

Dependent Claim 190 words

torsional exciter for a rotating structure, comprising: a rotary hydraulic actuator including a first element and a second element, said second element being rotatable relative to said first element; means for securing one of said first and second elements to said rotating structure; an inertial mass mounted on the other of said first and second elements; a hydraulic power supply for supplying pressurized fluid; and electrohydraulic means for controlling said actuator, said electrohydraulic means including: (a) means for selectively producing a position command signal correlated to a desired angular position of said inertial mass with respect to said rotating structure; (b) means for producing a position feedback signal correlated to the actual angular position of said inertial mass with respect to said rotating structure; (c) a controller responsive to said common and feedback signals for producing a control signal; and (d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator angularly displaces said inertial mass with respect to said rotating structure; whereby a torsional force is applied to said rotating structure.

Claim 22

Dependent Claim 190 words

torsional exciter for a rotating structure, comprising: a rotary hydraulic actuator including a first element and a second element, said second element being rotatable relative to said first element; means for securing one of said first and second elements to said rotating structure; an inertial mass mounted on the other of said first and second elements; a hydraulic power supply for supplying pressurized fluid; and electrohydraulic means for controlling said actuator, said electrohydraulic means including: (a) means for selectively producing a position command signal correlated to a desired angular position of said inertial mass with respect to said rotating structure; (b) means for producing a position feedback signal correlated to the actual angular position of said inertial mass with respect to said rotating structure; (c) a controller responsive to said common and feedback signals for producing a control signal; and (d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator angularly displaces said inertial mass with respect to said rotating structure; whereby a torsional force is applied to said rotating structure.

Claim 23

Dependent Claim 55 words

The exciter of claim 17 wherein said electrohydraulic means further includes: a torque setpoint circuit for selectively producing a torque command signal correlated to a desired torque applied to said rotating structure; and wherein said controller is responsive to said torque command signal for modifying said control signal in response to said torque command signal.

Claim 24

Dependent Claim 90 words

The exciter of claim 17 wherein said electrohydraulic means further includes: a torque setpoint circuit for selectively producing a torque command signal correlated to a desired torque applied to said rotating structure; and means for producing a torque feedback signal dependent on the actual torque applied to said rotating structure; and wherein said controller is responsive to said torque command and torque feedback signals for modifying said control signal in response to said torque command and torque feedback signals; whereby a controlled torsional force is applied to said rotating structure.

Claim 25

Dependent Claim 62 words

The exciter of claim 19 wherein said actuator further includes a first chamber and a second chamber and wherein said means for producing a torque feedback signal includes first and second pressure transducers and an interface circuit for producing a differential pressure signal dependent on the actual torque applied to said rotating structure, said differential pressure signal constituting said torque feedback signal.

Claim 26

Dependent Claim 32 words

The exciter of claim 18 or 19 wherein said torque setpoint circuit is adjustable for producing a random variation in the amplitude or frequency of the torque applied to said rotating structure.

Claim 27

Dependent Claim 52 words

The exciter of claim 17 wherein said first actuator element is a housing and said second actuator element is a driveshaft and wherein said inertial mass is a disc mounted on said driveshaft, said exciter further including a mounting plate secured to said housing for mounting said housing on said rotating structure.

Claim 28

Dependent Claim 145 words

The exciter of claim 17 wherein said first actuator element is a housing and said second actuator element is a driveshaft and wherein said inertial mass is a disc having arcuate slots, said disc being mounted on said driveshaft, said exciter further including a mounting plate secured to said housing for mounting said actuator on said rotating structure, said mounting plate being secured to said housing by mounting means including spacers extending through said slots and disposed between said housing and said disc, and wherein said means for producing a position feedback signal includes a first pin fixed to said housing and a second pin fixed to said disc, a first detector for sensing said first pin and a second detector for sensing said second pin and an interface circuit for producing an average position signal, said average position signal constituting said position feedback signal.

Claim 29

Independent Claim 157 words

A method for torsionally exciting a rotating structure, including the steps of: securing one element of a rotary hydraulic actuator to the rotating structure; mounting an inertial mass on a second element of the actuator; providing a supply of pressurized fluid; and controlling the actuator for angularly displacing the second element with respect to the first element by (a) selectively producing a position command signal correlated to a desired angular position of the inertial mass with respect to the rotating structure; (b) producing a position feedback signal correlated to the actual angular position of the inertial mass with respect to the rotating structure; (c) producing a control signal in response to the command and feedback signals; and (d) controlling the supply of pressurized fluid to the actuator in response to the control signal such that the actuator angularly displaces the inertial mass with respect to the rotating structure; thereby applying a torsional force to the rotating structure.

Claim 30

Independent Claim 157 words

A method for torsionally exciting a rotating structure, including the steps of: securing one element of a rotary hydraulic actuator to the rotating structure; mounting an inertial mass on a second element of the actuator; providing a supply of pressurized fluid; and controlling the actuator for angularly displacing the second element with respect to the first element by (a) selectively producing a position command signal correlated to a desired angular position of the inertial mass with respect to the rotating structure; (b) producing a position feedback signal correlated to the actual angular position of the inertial mass with respect to the rotating structure; (c) producing a control signal in response to the command and feedback signals; and (d) controlling the supply of pressurized fluid to the actuator in response to the control signal such that the actuator angularly displaces the inertial mass with respect to the rotating structure; thereby applying a torsional force to the rotating structure.

Claim 31

Dependent Claim 38 words

The method of claim 24 further including the steps of: selectively producing a torque command signal correlated to a desired torque applied to the rotating structure; and modifying the control signal in response to the torque command signal.

Claim 32

Dependent Claim 56 words

The method of claim 24 further including the steps of: selectively producing a torque command signal correlated to a desired torque applied to the rotating structure; producing a torque feedback signal correlated to the actual torque applied to the rotating structure; and modifying the control signal in response to the torque command and torque feedback signals;

Claim 33

Dependent Claim 10 words

thereby applying a controlled torsional force to said rotating structure.

Claim 34

Dependent Claim 10 words

thereby applying a controlled torsional force to said rotating structure.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-08-17	1985-02-16	1985-08-18	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-08-17	1989-02-16	1989-08-18	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-08-17	1993-02-16	1993-08-18	$7700.00	Window Closed / Lapsed

Torsional exciter for a rotating structure

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