Adaptive-passive vibration control system

• US 5,564,537 A
• Filed: 04/04/1994
• Issued: 10/15/1996
• Est. Priority Date: 04/04/1994
• Status: Expired due to Fees

• Current Assignee: Cooper Tire & Rubber Company (Goodyear Tire & Rubber Company)
• Original Assignee: Cooper Tire & Rubber Company (Goodyear Tire & Rubber Company)
• Inventors: Shoureshi, Rahmat A.
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): Poon, Peter M.
• Application Number:
  US08/222,085
• Time in Patent Office: 925 Days
• Field of Search: 188/378, 188/379, 188/380, 188/279, 267/136, 267/137, 267/141, 267/195, 267/291, 267/175, 267/177, 267/182, 267/140.11, 267/140.13, 248/560, 248/562, 248/566, 248/636, 248/550
• US Class Current: 188/380
• CPC Class Codes: D06F 33/48 Preventing or reducing imbalance or noise
• CPC Class Codes: D06F 34/08 Control circuits or arrangements thereof
• CPC Class Codes: D06F 34/16 Imbalance
• CPC Class Codes: D06F 37/24 in machines with a receptacle rotating or oscillating about a vertical axis
• CPC Class Codes: D06F 37/245 Damping vibrations by displacing, supplying or ejecting a material, e.g. liquid, into or from counterbalancing pockets
• CPC Class Codes: F16F 15/02 Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems F16F15/005 takes precedence ; layered products B32B; suppression of vibration in ships B63; relieving load on bearings, using magnetic means F16C39/06
• CPC Class Codes: F16F 15/04 using elastic means single elements or their attachment F16F1/00 - F16F13/00; F16F15/023, F16F15/03 take precedence
• CPC Class Codes: F16F 15/067 using only wound springs
• CPC Class Codes: F16F 7/1005 characterised by active control of the mass

Abstract

A passive/adaptive vibration control system is provided wherein various elements of the system may be adapted on-line in response to sensed vibrations. A spring/mass vibration absorber is attached to a vibrating body to absorb energy generated by that body, to minimize the transmission of vibrations to a structure in mechanical communication with the vibrating body. In one embodiment of the present invention, the mass of the vibration absorber may be adjusted, on-line, to compensate for sensed vibrations. A vibration sensor is connected to either the vibrating body or the attached structure so as to sense the level of vibration above a desired level and to send a signal representative of that vibration to an electronic controller. The electronic controller is designed to instruct the actuator to adapt the mass to compensate for the sensed vibration. In additional embodiments of the system, the stiffness of the spring, rather than the mass of the weight, may be adjusted on-line to "tune" the vibration absorber. Further, if more than one excitation frequency is present, a plurality of on-line adaptive and/or purely passive vibration absorbers may be cascaded so as to minimize vibrations due to a plurality of excitation frequencies. Depending on the number of vibration axes to be attenuated, one or a plurality of passive/adaptive vibration absorber elements may be used.

Claims

1. A vibration filtering/absorbing control system for minimizing the transmission of vibrations from a vibrating body to at least one structure in mechanical communication with the vibrating body, comprising:

a first spring/mass vibration controlling system including a first spring and a first weight connected to said spring forming a combined vibration filtering/absorbing means;

said vibration filtering/absorbing means connected to said vibrating body;

an actuator means for varying the mass of said weight and/or the stiffness of said spring;

a sensor for sensing the vibration in the vibrating body and/or in the structure connected to the vibrating body, said sensor providing a variable output feedback signal corresponding to the sensed vibration; and

an electric controller connected to receive said feedback signal from said sensor indicative of the sensed vibration and to relay a control signal to said actuator,

said sensor and controller thereby forming the adaptive portion of an adaptive-passive vibration filter/absorber and said controller instructing said actuator to automatically adjust the spring/mass system in a manner to minimize the sensed vibrations.

2. The vibration control system of claim 1, wherein said sensor directly senses the excitation frequency of said vibrating body.

3. The vibration control system of claim 1, wherein said sensor is a vibration sensor, and is connected to said controller in a feedback loop.

4. The vibration control system of claim 3, wherein said weight includes a chamber of constant volume, said weight having a mass of m_o.

5. The vibration control system of claim 4, additionally including a fluid source in fluid communication with said chamber of said weight, and wherein said mass of said weight is varied by adjusting the amount of fluid in said chamber.

6. The vibration control system of claim 5, wherein said actuator comprises:

at least one inlet valve, for admitting fluid from said fluid source into said chamber in response to a command from said electronic controller to said inlet valve; and

at least one outlet valve, for evacuating fluid from said chamber in response to a signal from said electronic controller to said outlet valve.

7. The vibration control system of claim 1 additionally comprising:

a second spring, connected in series with said first spring; and

a second weight connected to said second spring.

8. The vibration control system of claim 7, wherein said second weight has a variable mass.

9. The vibration control system of claim 7, wherein said second spring has a variable stiffness.

10. A vibration control system for minimizing the transmission of vibrations from a vibrating body to at least one structure in mechanical communication with the vibrating body, comprising:

a mechanical spring;

a motor, including a motor shaft, said mechanical spring being attached to the motor shaft;

a support bracket through which a first end of the spring is passed;

a weight connected to the first end of said spring;

a sensor for sensing the vibration in the system due to the vibrating body; and

an electronic controller connected to receive a signal from said sensor indicative of said sensed vibration and to relay a control signal to said motor to instruct said motor to automatically adjust the stiffness of said spring in response to said sensed vibrations;

wherein rotation of the motor in a first direction forces the upper section of the spring to pass downward through the bracket and increase the number of active spring coils; and

wherein rotation of the motor in a second direction retracts coils of the spring back upward through said bracket, thus reducing the active number of spring coils.

11. The vibration control system of claim 10, wherein said motor is a stepper motor.

12. A vibration control system for minimizing the transmission of vibrations from a vibrating body to at least one structure in mechanical communication with the vibrating body, comprising:

a spring, including a pneumatic spring comprising an air bag, the stiffness of which is variable over a continuum of stiffnesses, said spring being connected at a first end to the vibrating body;

a weight connected to a second end of said spring;

an actuator for varying the stiffness of said spring, comprising a pump for increasing the air pressure within said air bag, and a release valve for reducing the air pressure within said air bag;

a sensor for sensing the vibration in the system due to the vibrating body; and

an electronic controller connected to receive a signal from said sensor indicative of said sensed vibration and to relay a control signal to said actuator said sensor and controller thereby forming the adaptive portion of an adaptive-passive vibration filter/absorber and said controller instructing said actuator to automatically adjust the stiffness of said spring in response to said sensed vibrations.

13. The vibration control system of claim 12, wherein said spring additionally includes a mechanical spring connected to said air bag.

14. A vibration control system for minimizing the transmission of vibrations from a vibrating body to at least one structure in mechanical communication with the vibrating body, comprising:

a spring, the stiffness of which is variable over a continuum of stillnesses, said spring being connected at a first end to the vibrating body;

a weight connected to a second end of said spring;

an actuator for varying the stiffness of said spring;

a sensor for sensing the vibration in the system due to the vibrating body;

an electronic controller connected to receive a signal from said sensor indicative of said sensed vibration and to relay a control signal to said actuator said sensor and controller thereby forming the adaptive portion of an adaptive-passive vibration filter/absorber and said controller instructing said actuator to automatically adjust the stiffness of said spring in response to said sensed vibrations; and

wherein said spring includes at least one strip of a shape memory alloy, and wherein said actuator includes a current source, electrically connected to said at least one strip of shape memory alloy, said current source for applying a current to said shape memory alloy for changing the stiffness of said alloy and said spring.

15. A vibration control system for minimizing the transmission of vibrations from a vibrating body to at least one structure in mechanical communication with the vibrating body, comprising:

a mechanical spring connected to the vibrating body;

a weight, including a chamber of constant volume, connected to said spring;

a fluid source in communication with said chamber;

an inlet valve for admitting fluid from said fluid source to said chamber;

an outlet valve for releasing fluid from said chamber;

a vibration sensor for sensing the vibration in the system due to the vibrating body; and

an electronic controller connected to receive a signal indicative of sensed vibrations above a reference vibration level, and to relay control signals to said inlet and said outlet valves to automatically adjust the fluid level in said chamber in response to said sensed vibrations, said sensor and controller thereby forming the adaptive portion of an adaptive-passive vibration filter/absorber.

16. A vibration control system for minimizing the transmission of vibrations from a vibrating body to at least one structure in mechanical communication with the vibrating body, comprising:

a first vibration absorber, including a first spring and a first weight;

a second vibration absorber connected in series with said first vibration absorber, including a second spring and a second weight;

at least one vibration sensor, for sensing vibrations present due to said vibrating body;

an electronic controller connected to receive a signal indicative of the sensed vibrations from said vibration sensor said sensor and controller thereby forming the adaptive portion of an adaptive-passive vibration filter/absorber;

wherein said series combination of said first vibration absorber and said second vibration absorber is connected to the vibrating body; and

wherein at least one of the stiffness of said first spring and the mass of said first weight may be varied in response to said sensed vibrations.

17. The vibration control system of claim 16, wherein at least one of the stiffness of said second spring and the mass of said second weight may additionally be varied in response to said sensed vibrations.