Multi-modal and multi-degree-of-freedom piezoelectric active vibration isolation platform and working method therefor

A multi-modal and multi-degree-of-freedom piezoelectric active vibration isolation platform, comprising an upper platform, a lower platform, first to fourth vibration isolation modules, and a control module, wherein

• the first to fourth vibration isolation modules have a same structure, and each comprises a passive vibration isolation unit and an active vibration isolation unit;
• the passive vibration isolation unit comprises an upper connector, a lower connector, a cross Hooke hinge, and a first acceleration sensor, wherein the upper connector and the lower connector are regular quadrangular prisms with the same cross-sectional shape, each comprises first to fourth side walls perpendicularly and fixedly connected end to end in sequence;
• two ends of the cross Hooke hinge are separately connected with a lower end face of the first acceleration sensor and an upper end face of the lower connector, so that the first to fourth side walls of the upper connector and the lower connector are coplanar one by one, and two rotating shafts of the cross Hooke hinge are separately perpendicular to the first side wall and the second side wall of the upper connector;
• a threaded blind hole is provided in the center of a lower end face of the lower connector;
• the first acceleration sensor is arranged on an end face of the upper connector, connected in series with the upper connector and the upper platform, and configured to sense a vibration signal of the upper platform;
• the active vibration isolation unit comprises a fixed beam, a pre-tightening bolt, a second acceleration sensor, and a driving component;
• the fixed beam and the lower connector are regular quadrangular prisms with the same cross-sectional shape, and a countersunk through hole through which the pre-tightening bolt penetrates is provided in the center of a lower end face of the fixed beam;
• the driving component comprises 2N piezoelectric ceramic plates, and N is a natural number greater than or equal to 1;
• the shape of the piezoelectric ceramic plate is the same as the cross-sectional shape of the lower connector, and a through hole through which the pre-tightening bolt penetrates is provided in the center of the piezoelectric ceramic plate;
• the pre-tightening bolt sequentially penetrates through the fixed beam and the 2N piezoelectric ceramic plates, and is then in threaded connection with the threaded blind hole on the lower end face of the lower connector, to tightly clamp the 2N piezoelectric ceramic plates between the fixed beam and the lower connector;
• the 2N piezoelectric ceramic plates are polarized along a thickness direction thereof, and polarization directions of the adjacent piezoelectric ceramic plates are opposite;
• the second acceleration sensor is arranged in an inner hole of the fixed beam, and configured to sense a vibration signal of the fixed beam;
• the upper platform and the lower platform are both square flat plates, the upper platform is configured to be fixedly connected with a vibration isolation object, and the lower platform is configured to be fixedly connected with a vibration source needing to be fixed to the vibration isolation object;
• an array of the first to fourth vibration isolation modules is between the upper platform and the lower platform, upper end faces of the upper connectors of the first to fourth vibration isolation modules are all fixedly connected with the upper platform, and the lower end faces of the fixed beams are all fixedly connected with the lower platform, so that the first side walls of the upper connectors in the first and second vibration isolation modules are coplanar, the first side walls of the upper connectors in the third and fourth vibration isolation modules are coplanar, and the first side walls of the upper connectors in the first and third vibration isolation modules are parallel;
• and
• the control module is electrically connected with the first acceleration sensors, the second acceleration sensors, and the driving components in the first to fourth vibration isolation modules separately, and is configured to control the driving components in the first to fourth vibration isolation modules to work according to sensed data of the first acceleration sensors and the second acceleration sensors in the first to fourth vibration isolation modules.