A control system for a microgravity isolation mount

Jones, D.; Owens, A.R.; Owen, R.G.

doi:10.1109/87.508880

Cited by 4 publications

(2 citation statements)

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“…The use of a contact system such as this should be compared with non-contact proposals such as in Ref. 11, which discusses use of magnetic actuators. Magnetic systems provide better passive damping in general but also tend to be heavier than the small polymer devices described here.…”

Section: Discussionmentioning

confidence: 99%

“…It consists of a bandpass filter to reject frequencies above and below the range needed for control and a Proportional-plus-Derivative (PD) control module. The proportional response couples to the displacement x=D-Y+yo, (8) and changes the effective spring constant. The derivative response is based on the time rate of change of the relative displacement dx/dt, and produces the desired additional (viscous-like) damping.…”

Section: Control Modelmentioning

confidence: 99%

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Piezoelectric polymer actuators in a vibration isolation application

Bohannan

Schmidt

Conant

et al. 2000

Smart Structures and Materials 2000: Electroactive Polymer Actuators and Devices (EAPAD)

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We present results from development and testing of lightweight actuators made of the piezoelectric polymer PVDF. The prototype being developed is intended for microgravity applications in space and has been tested aboard NASA's Reduced Gravity Platform. The design has been driven by the requirements for a full three-dimensional (six-degreeof-freedom) environment. Incorporation of additional electrical leads into the actuators themselves may remove the need for a separate umbilical to the suspended experiment. Linear equations describing the displacement of piezoelectric bimorphs were developed and applied to the bellows actuator including the epoxy layer. Properties for the piezoelectric layers were obtained from the literature; properties for the epoxy layer were obtained through ultrasonic testing. To assess the validity of the assumed linearity of the actuator, we conducted nonlinear finite element analysis, which indicated a high degree of linearity on contraction and up to a maximum of 5% deviation on expansion to full deflection (about 6 mm). We have developed and tested a proportional-plus-derivative (PD) control system for use with the actuator in one dimension using a novel folded pendulum to simulate a zero-g environment. Passive and active characteristics are both in agreement with theoretical predictions.

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Section: Discussionmentioning

confidence: 99%

Section: Control Modelmentioning

confidence: 99%