Provided is an ultra-stable multi-directional low-frequency actuator, including a baseplate, a bearing plate, a connecting mechanism, and two executing mechanisms symmetrically arranged on the baseplate about a Y axis. Both ends of a lower part of the support leg are connected with the baseplate through one high-static low-dynamic spring damper and one vertical executer arranged in parallel, respectively. Both ends of an upper part of the support leg are provided with one sensing component, respectively. A horizontal executer and an elastic component are arranged in parallel between each of both sides of a lateral support seat and a first groove, and sensing components corresponding to the horizontal executers one by one are arranged at an inner side of the support leg. The connecting mechanism is configured to connect two support legs, both ends of the bearing plate are mounted at the upper parts of the two support leg.

Disclosed is a multi-modal and multi-degree-of-freedom piezoelectric active vibration isolation platform and a working method therefor. The piezoelectric active vibration isolation platform includes an upper platform, a lower platform, a control module, and four vibration isolation modules, where the vibration isolation module includes a passive vibration isolation unit and an active vibration isolation unit; the passive vibration isolation unit includes an upper connector, a lower connector, a cross Hooke hinge, and a first acceleration sensor; the active vibration isolation unit includes a fixed beam, a pre-tightening bolt, a second acceleration sensor, and a driving component; the platform can provide active vibration isolation for the longitudinal (axial) vibration and the bending vibration in any radial direction of a vibration isolation object, and has the advantages of fast response, resistance to electromagnetic interference, and light weight.

A microelectromechanical membrane transducer includes: a supporting structure; a cavity formed in the supporting structure; a membrane coupled to the supporting structure so as to cover the cavity on one side; a cantilever damper, which is fixed to the supporting structure around the perimeter of the membrane and extends towards the inside of the membrane at a distance from the membrane; and a damper piezoelectric actuator set on the cantilever damper and configured so as to bend the cantilever damper towards the membrane in response to an electrical actuation signal.