Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Mechanical Engineering | en_US |
| dc.contributor.advisor | Jing, Xingjian (ME) | en_US |
| dc.contributor.advisor | Navarro-Alarcon, David (ME) | en_US |
| dc.creator | Zhou, Zengcheng | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/13820 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Finite-time control for active vehicle suspension systems | en_US |
| dcterms.abstract | With the rapid development of the vehicle industry, vehicle suspension systems, which serve as an elastic connection between the vehicle body and the wheels, have gathered increasing attention to enhance ride comfort and driving maneuverability. Sophisticated vehicle suspension systems can adapt to road imperfections and vibrations, thus maintaining safety requirements, improving ride comfort, and even avoiding physical fatigue. Compared with traditional passive suspensions and semi-active ones, active vehicle suspension systems are equipped with actuators to adjust the relative displacement between the vehicle body and the wheels, which can effectively handle the undesired vibrations generated by extremely poor road conditions. However, existing nonlinear control strategies for active suspensions may suffer from uncertain dynamics, external disturbances, slow convergence, high energy consumption, and actuator nonlinearities. To effectively address these practical issues, this thesis primarily focuses on the finite-time energy-saving control design for active vehicle suspension systems to enhance ride comfort and driving safety. Four different active suspension control algorithms are proposed in this thesis to guarantee vehicle performance under various critical conditions. Therefore, the requirements of ride comfort and driving safety for active suspensions can be sufficiently satisfied. | en_US |
| dcterms.abstract | The main investigations and contributions of this thesis can be enumerated subsequently. (1) A novel finite-time saturated control is designed for AVSSs to handle input saturations, dead zones, and external disturbances. No exact model information is required, leading to a completely model-free control structure. Besides, the control input signal can be naturally constrained in a prior-known range without any extra anti-saturation design. The control algorithm is designed to be nonsingular and continuous to avoid singularity issues and alleviate the chattering phenomenon. (2) To deal with the high energy consumption, a bioinspired X-shaped reference model is integrated into a fixed-time safe-by-design control scheme. Inspired by the biological motion dynamics, beneficial stiffness, and damping effects can be preserved to obtain advantageous suspension performance with potential energy conservation. The asymmetric time-varying barrier Lyapunov functions are constructed to guarantee the displacement and velocity constraints. Furthermore, the fixed-time stability of the closed-loop system is rigorously validated such that the convergence time is irrelevant to initial states to enhance the transient property and disturbance-rejection ability. (3) A predefined-time fault-tolerant control is proposed for AVSSs to deal with external disturbances and actuator faults. In addition to the reference X-dynamics with beneficial nonlinearities, a conditional disturbance cancellation design is defined to reserve beneficial disturbance characteristics, leading to enhanced energy-saving performance. Both the predefined convergence time and user-defined residual bound can be guaranteed which are independent of initial states and control parameters. Moreover, the continuous piecewise function and the quadratic fraction inequality are integrated to achieve nonsingular property and reduce chattering. (4) Different from existing active suspension control which neglected the effect of partial state estimation, this thesis proposes a predefined-time output-feedback control structure for AVSSs. A predefined-time extended state observer is developed utilizing the time-varying scaling function to approximate the unavailable velocities and disturbances. Despite the X-mechanism reference dynamics with beneficial suspension nonlinearities, the properties of both disturbances and state couplings are evaluated and preserved according to the effect characterization method, thus improving the potential energy conservation. The settling time of the whole control scheme can be user-specified with just one constant, which is free from dependence on initial states and control gains. Finally, compared with existing active suspension control designs, the proposed control algorithms are applied on a quarter-car experimental platform to present superior control performance over ride comfort, driving safety, and energy conservation. | en_US |
| dcterms.extent | xii, 165 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2025 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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