Vibration isolation system using plural signals for control

An apparatus for isolating an element from movements experienced in a base element to which the element is attached, comprising:

• first movement measurement means producing a signal related to the movement experienced by said base element;
• second movement measurement means producing a second signal related to the movement experienced by said element;
• actuator means for selectively mutually displacing said element from said base element;
• and,
• control means for selectively operating said actuator means responsively to said signal and to said second signal to reduce the movement of said element.

A vibration attenuation device comprising plural active isolation fittings arranged between an element and a base element to provide six degrees of freedom of movement of said element relative to said base element, each of said fittings comprising:

• first movement measurement means producing a signal related to the movement experienced by said base element;
• second movement measurement means producing a second signal related to the movement experienced by said element;
• actuator means for selectively changing the separation between said element from said base element;
• and,
• control means for selectively operating said actuator means responsively to said signal and to said second signal to decrease the separation between the element and the base element when said first and second movement measurement means indicate the element and base element are moving toward each other, and to increase the separation between the element and the base element when said first and second movement measurement means indicate the element and base element are moving away from each other.

A high stiffness active isolation device for reducing the vibrations transmitted between stiffly connected first and second elements, comprising:

• first and second flexible interconnection means, said first means interconnecting the first element to a first end of the device and said second means interconnecting said second element to a second end of the device, both said interconnection means stiffly operating in a first direction and loosely operating in directions perpendicular to said first direction;
• first measurement means, positioned to measure movements along said first direction at said first end of the device and providing a first signal related thereto;
• second measurement means, positioned to measure movements along said first direction at said second end of the device and providing a second signal related thereto;
• first and second signal conditioning means filtering respectively said first and second signals;
• a high gain controller producing a feedback control signal from said first signal;
• a feedforward controller producing a feedforward signal from said second signal;
• control means combining said feedback control signal and said feedforward signal to produce a control signal;
• actuator means responsive to said control signal to relatively displace said first and second elements along said first direction.

An apparatus for isolating an element from vibrations experienced in a base element to which the element is attached, comprising:

• a base housing carrying,
• (1) a means for connecting said base element to said base housing,
• (2) an actuator means for selectively displacing said element from said base element, and
• (3) a first vibration measurement means for producing a first signal related to vibration experienced by said base element;
• a top housing carrying,
• (1) a means for connecting said element to said top housing, and
• (2) a second vibration measurement means for producing a second signal related to vibrations experienced by said element;
• said top housing internally including,
• (3) a longitudinally compliant element for attenuating the transfer of vibrations between the base element and the element, and
• (4) a shaft connecting said top housing, said compliant element, and said actuator means in a longitudinal arrangement;
• and,
• control means for selectively operating said actuator means responsively to said signal and to said second signal to reduce the transmission of vibration between said element and said base element.

An apparatus for isolating an element from vibrations occurring at a base element by detecting the vibrations and displacing said element to negate any displacement the element would experience as a result of said vibrations, comprising:

• an apparatus body having a first end connected to said element and a second end connected to said base element;
• and
• first and second vibration measurement means for detecting said vibrations connected to said body first and second ends, respectively,
• wherein said first and second vibration measurement means produce signals for controlling the displacement of said element.

An apparatus for isolating an element from vibrations occurring at a base element by detecting the vibrations and displacing said element to negate any displacement the element would experience as a result of said vibrations, comprising:

• an apparatus body having a first end connected to said element and a second end connected to said base element;
• a piezoelectric linear actuator for actively displacing said element in response to the detection of said vibrations;
• and
• a compliant element for passively attenuating said vibrations,
• wherein said compliant element and said linear actuator are coaxial with and contained within said body.