The invention provides a negative-stiffness-adjustable torsional quasi-zero stiffness vibration
isolator and a control method. The negative-stiffness-adjustable torsional quasi-zero stiffness vibration
isolator comprises a front shell, a rear shell, a front
washer, a rear
washer, a rotary sleeve used for fixing a transmission shaft, and a permanent
magnet excitation mechanism. A rotary component of the permanent
magnet excitation mechanism is fixedly connected with the rotary sleeve and is fixedly connected with a permanent
magnet through a rubber pad. A
magnetic flux generated by the permanent magnet passes through the rubber pad, the rotary component, an air gap and an annular permanent magnet clamping mechanism to return to the permanent magnet to form a
magnetic flux loop, and the magnetic stress is generated in the air gap and is applied to the rotary component, so that a torsional
magnetic spring is formed by the rotary component in the thickness direction of the air gap. The
magnetic field intensity in the air gap is changed by adjusting the intensity of current supplied to an exciting coil, and then the
negative stiffness of the
magnetic spring is changed to be close to thepositive stiffness achieved through a
rubber bearing, so that the
system stiffness is made to the quasi-zero state. The negative-stiffness-adjustable torsional quasi-zero stiffness vibration isolatorcan effectively transmit the driving torque and can isolate the disturbance torque; the
system stiffness is actively controlled, so that low-frequency
torsional vibration is well isolated; and the negative-stiffness-adjustable torsional quasi-zero stiffness vibration
isolator is suitable for a precision rotating
system.