Electromagnetic pneumatic quasi-zero stiffness vibration isolator with adjustable stiffness

The invention discloses an electromagnetic pneumatic quasi-zero stiffness vibration isolator with adjustable stiffness. The vibration isolator comprises a base; a set of pneumatic springs and two sets of electromagnetic springs are arranged on the base; the two sets of electromagnetic springs are fixedly connected with the two sides of a double-end bolt separately, and the double-end bolt can be driven by the two sets of electromagnetic springs to move up and down; a connecting piece is matched with the double-end bolt; the pneumatic springs are fixedly connected with the connecting piece, and the connecting piece can be driven by the pneumatic springs to move up and down; the connecting piece is connected with a load platform; and a load is placed on the load platform. Positive stiffness generated by the pneumatic springs is balanced by negative stiffness generated by the electromagnetic springs, and therefore a static balance position is at a quasi-zero stiffness state; when the load is changed, the air pre