Methods and devices for active vibration damping of an optical structure
A vibration damper assembly that may be attached and moved about a payload or optical mount surface of an optical structure such as an optical table. The vibration damper assembly may include a sensor and an actuator that may be disposed within a housing. In some embodiments, the vibration damper assembly or components thereof may be incorporated into an optical structure in the form of an optical component to be disposed or mounted on an optical mount surface of an optical structure such as an optical table. Embodiments of the vibration damper system may include a controller in communication with the damper assembly Embodiments of the controller may use adaptive tuning, auto-ranging selection of gain factors and other features in order to optimize damping performance.
1. A method of automatically selecting an appropriate range of input vibration signal detection in an active vibration damper system, comprising:
providing a vibration damper system for an optical structure including a vibration sensor, an actuator and a controller coupled to both the vibration sensor and the actuator by a control channel and the controller having at least two vibration feedback signal inputs with gain factors appropriate to a signal strength range for the vibration feedback signal inputs;
monitoring an amplitude value of a vibration feedback signal from the vibration sensor;
comparing the amplitude value of the vibration feedback signal to a pre-selected range of signal values over a pre-selected period of time; and
switching the vibration feedback signal to an appropriate vibration feedback signal input with an appropriate gain factor for the amplitude value of the vibration feedback signal in the controller.
2. The method of claim 1 wherein the vibration feedback signal is switched to a lower gain vibration feedback signal input if the amplitude value of the vibration feedback signal was too high for the pre-selected range.
3. The method of claim 1 wherein the vibration feedback signal is switched to a higher gain vibration feedback signal input if the amplitude value of the vibration feedback signal was too low for the pre-selected range.
4. The method of claim 1 further comprising:
monitoring the vibration feedback signal and switching the vibration feedback signal to a vibration feedback signal input with a lowest gain factor;
detecting an amplitude of the vibration feedback signal that is still out of an acceptable range of vibration feedback signal amplitude values; and
determining whether a vibration overload condition exists for the active damper system.
5. The method of claim 4 wherein the controller is configured to generate an error signal when an overload condition exists and further comprising generating an error signal with the controller when it is determined that a vibration overload condition exists.
6. The method of claim 5 wherein the generation of an error signal comprises generating a visual error signal.
7. The method of claim 1 wherein monitoring the amplitude value of the vibration feedback signal from the vibration sensor comprises monitoring a mean-square amplitude value of the vibration feedback signal.
8. A method of determining a payload change with an active vibration damper system coupled to an optical structure, comprising:
providing an active vibration damper system including a vibration sensor, an actuator and a controller coupled to both the vibration sensor and the actuator by a control channel and the controller having a vibration feedback signal input with a gain factor appropriate to a signal strength range for the vibration feedback signal input;
monitoring a vibration feedback signal from the vibration sensor for vibration overload conditions;
detecting a vibration overload condition;
disabling a drive signal to the actuator from the controller; and
determining whether the vibration overload condition still exists.
9. The method of claim 8 wherein a determination of payload change is indicated by the controller to a user when the overload condition ceases to exist after the drive signal to the actuator from the controller is disabled.