Xueyan Yan

Semi-active electromagnetic dampers are widely recognized for their capability to provide tunable mechanical characteristics and effectively enhance vibration control performance in electrified vehicle suspensions. However, precise damping force tracking remains challenging when the system is affected by mechanical friction, inertial disturbances, and circuit parameter uncertainties. To address these issues, this study proposes a hierarchical control architecture that integrates both mechanical and electrical dynamics for a semi-active DC-DC converter-based electromagnetic damper (DCEMD). The hierarchical control framework, consisting of an upper-layer and a lower-layer controller, is developed accordingly. In this system, the upper-layer H_∞ robust controller suppresses external mechanical disturbances through a disturbance force observer, while the lower-layer model-based adaptive backstepping sliding mode controller compensates for time-varying circuit parameters and ensures accurate damping force tracking. The DCEMD's broad and continuously controllable damping characteristics are experimentally validated, and its control performance is verified on a semi-active electromagnetic suspension experimental platform that incorporates realistic nonlinearities and disturbances. Experimental results demonstrate that the hierarchical control scheme and the designed DCEMD achieve superior vibration isolation and force-tracking precision compared with traditional semi-active systems and several benchmark control methods.

The stability analysis of networked switched systems becomes highly challenging when multiple factors—such as frequent switching, denial-of-service (DoS) attacks, transmission delays, and actuator faults—coexist under an event-triggered mechanism (ETM). These intertwined factors cause complex timing mismatches that invalidate most synchronization-based control frameworks. To address this challenge, this article proposes a resilient event-triggered fault-tolerant control strategy that captures multisource asynchrony by classifying multiple key instants and modeling their interactions through a Lyapunov-based scheme. Unlike most existing studies that rely on synchronized switching assumptions or oversimplify the timing structure by ignoring delays and DoS attacks, this work explicitly incorporates these asynchronous phenomena into a unified analytical framework. First, to ensure timely packet transmission, a hybrid ETM is designed by combining time-triggering and event-triggering conditions. A switched Lyapunov function is then constructed by classifying different intervals, thereby unifying the analysis of asynchronous behaviors and DoS-induced disruptions. Furthermore, a resilient codesign strategy is developed, where the event-triggered parameters and fault-tolerant control gains are jointly designed under an explicit trade-off among the average dwell time parameter of switching signals, DoS attack parameters, and the sampling period. Under the proposed framework, global exponential stability with $H_{\infty } $ performance is guaranteed despite the presence of transmission delays, actuator faults, and DoS attacks. Finally, the effectiveness of the proposed method is demonstrated using a quarter-vehicle suspension system.