An integrated isolator-absorber with quasi-zero stiffness for vibration isolation and semi-actively controlled variable-stiffness absorption

This paper proposes a semi-active torsional vibration damper that integrates quasi-zero-stiffness isolation (QZSI) with variable-stiffness absorption (VSA), making it suitable for torsional vibration control in vehicle transmission systems. Simplified series and parallel mode models of a hybrid electric vehicle (HEV) transmission system are established, and corresponding vibration characteristics are analyzed. Based on this, the design mechanism of the integrated torsional vibration damper is elaborated, an analysis of the system’s dynamic characteristics is conducted. To further enhance vibration suppression performance, a frequency tracking algorithm based on short-time Fourier transform (STFT) is proposed, enabling semi-active control of the QZSI-VSA. Dynamic models of the HEV transmission system incorporating the QZSI-VSA in both series and parallel modes are developed, and simulation analysis of vibration suppression performance under multiple operating conditions is carried out alongside hardware-in-the-loop (HIL) validation. The results demonstrate that the proposed QZSI-VSA effectively isolates low-frequency system vibrations and achieves significant vibration suppression within the designed frequency range. The STFT-based semi-active frequency tracking strategy exhibits strong robustness and engineering feasibility, providing an effective solution for vibration control in vehicle transmission systems.