Showing papers on "Active vibration control published in 1980"

Fixed position variable frequency pendular-type vibration absorber

Abstract: A variable frequency vibration absorber adapted to be fixedly mounted in a fixed vibration prone system to coact with the system principal vibration excitation source to control system vibration. The vibration absorber is bifilar in construction and the natural frequency thereof is varied in proportion to the frequency of the vibration being generated by the principal system excitation source.

Shock and vibration damping arrangement for vehicles

Abstract: not available for EP0027869Abstract of corresponding document: US4368900A mass such as a vehicle or craft, for example an aircraft, is cushioned against landing shocks and vibrations by an electronically controlled shock and vibration absorber system. For this purpose an electrical control signal is produced which takes into account several coefficients through the adjustment of potentiometers in a control circuit which continuously controls the damping characteristic curve of the shock and vibration absorber system.

Fixed position, fixed frequency pendular-type vibration absorber with frequency linearization

Abstract: A fixed frequency vibration absorber adapted to be fixedly mounted in a fixed vibration prone system. The vibration absorber is of the pendular-type with two dynamic masses suspended in pendular fashion from a base member, and with at least one coil spring acting upon the masses to establish and linearize the vibration absorber natural frequency.

Sound producing device for watches

Abstract: A sound producing device for watches comprising an electromagnetic exciting means having a coil and a permanent magnet, and first and second vibration plates disposed on opposite sides of the electromagnetic exciting means. The natural frequencies of both vibration plates are different from each other. The first vibration plate is vibrated by magnetic force and the vibration of the plate causes the resonant vibration of the second vibration plate.

ACOSS Four (Active Control of Space Structures) Theory. Volume II. Appendix

Abstract: : This is the Charles Stark Draper Laboratory, Inc., final technical report on its Actively Controlled Structures Theory Study. The objective of the research reported here was to develop the theoretical and analytical tools to support the successful implementation of active vibration control of large flexible spacecraft. Parallel efforts in theory and applications were initiated. For the theoretical effort, several representative design methods were selected for careful study focusing on an examination of the theoretical basis for each method and potential difficulties associated with their use in reduced-order large space structure controller design. The methods initially selected are characterized by constant-gain output feedback, the simplest form of active multivariable control; (1) Modal Decoupling, (2) Pole Assignment, (3) Optimal Output Feedback, (4) Suboptimal Output Feedback, and (5) Stochastic Optimal Output Feedback. A performance comparison of specific designs with these methods was made. Extensions to the published Kosut methods of suboptimal output feedback are developed, as well as the details of an algorithm necessary for a numerical solution. Techniques and conditions are developed for reduction of control (observation) spillover by placement of actuators (sensors), by synthesis of the actuator (sensor) influences, and by compensation of actuators (sensors).

Vibration sensor for an automotive vehicle engine

Abstract: A vibration sensor for an automotive vehicle having a piezoelectric element of diaphragm type for detecting mechanical vibrations from an internal combustion engine such as knocking frequency. The piezoelectric element is formed within a holder of plastic or the like and bonded thereto in a manner to accurately regulate the clamping pressure at the element periphery and regulate the vibration area thereof to accurately regulate the resonant frequency of the vibration sensor.

Vibration sensor for an automotive vehicle

Abstract: A vibration sensor for an automotive vehicle including a piezoelectric vibrator of cantilever type for detecting mechanical vibrations, such as knocking, from an engine body. The vibration sensor prevents the vibrator from being deformed by thermal stress even if temperature near the sensor rises sharply, so that a stable resonant frequency will be maintained when detecting the vibration of an engine body.

ACOSS Four (Active Control of Space Structures) Theory. Volume

Abstract: : The objective of the research reported here was to develop the theoretical and analytical tools to support the successful implementation of active vibration control of large flexible spacecraft. Parallel efforts in theory and applications were initiated. For the theoretical effort, several representative design methods were selected for careful study focusing on an examination of the theoretical basis for each method and potential difficulties associated with their use in reduced-order large space structure controller design. The methods initially selected are characterized by constant-gain output feedback, the simplest form of active multivariable control; (1) Modal Decoupling, (2) Pole Assignment, (3) Optimal Output Feedback, (4) Suboptimal Output Feedback, (5) Stochastic Optimal Output Feedback. A performance comparison of specific designs with these methods was made. Extensions to the published Kosut methods of suboptimal output feedback are developed, as well as the details of an algorithm necessary for a numerical solution.