Large-Displacement Low-Frequency Systems

Minus K has developed the technology to produce passive vibration isolation platforms capable of large displacements and low frequencies, vertical and horizontal, and suitable for some vehicle applications. Because of the passive, low-stiffness behavior, they cannot handle quasi-steady maneuver loads but they can be used to stabilize platforms for taking measurements or pointing during constant steady motion. They can be used with active systems such as an active hexapod to maintain the level of the base. The Minus K systems have high isolation performance, no air is required, they are relatively compact, and they eliminate the high power requirements of fully active large-displacement systems.

The figure shows a platform that was produced for a customer. The platform was designed for a 750 lb payload. It is approximately 42 in. in diameter and 36 in. high and is capable of displacements of +/- two inches, vertical and horizontal. It can be adjusted to a vertical natural frequency of 0.5 Hz for small displacements and, when oscillated at ± two inches, the frequency increases to only 0.67 Hz from nonlinear effects. Horizontal frequencies of 0.5 Hz can be achieved for both small displacements and ± two-inch displacements.