Compensation strategy for quasi-zero-stiffness vibration isolator under payload mismatch

The quasi-zero-stiffness (QZS) vibration isolators are effective in achieving low-frequency vibration isolation for a designed payload, but the isolation effect would be substantially reduced by payload mismatch. To tackle such a challenging problem, a compensating QZS (CQZS) vibration isolation system (VIS) is proposed to acquire QZS characteristics under arbitrary payloads. The dynamic characteristics of the CQZS VIS are analyzed to estimate the performance decline of vibration isolation under payload mismatch. Moreover, the compensation principle of the CQZS VIS is demonstrated, and then the CQZS VIS is fabricated by combining a passive QZS isolator and a compensation system. Finally, experiments are conducted to evaluate the compensation capability and vibration isolation performance enhance of the CQZS VIS. It is found that the CQZS VIS is able to compensate payload mismatch, and thus the QZS characteristic can be regained when the payload deviates from the designed one, which enabls the QZS VIS to achieve significant low-frequency vibration isolation under payload mismatch.