A novel general theory of skyhook control is proposed and applied to semi-active suspension control strategy design to improve the performance of the vehicle suspension system. Based on this theory, the mechanical impedance model of general theory of skyhook suspension is established. To design the suspension structure, the effect of the skyhook element and its parameters on suspension is analyzed. Then, adaptive fish swarm algorithm based on nonlinear dynamic visual field is used to optimize the parameters of general theory of skyhook control. To realize the general theory of skyhook control and verify it, a novel controllable inerter is designed and utilized into the semi-active suspension system. The simulation results demonstrate that the semi-active suspension with general theory of skyhook control can enhance the suspension performance obviously. Lastly, the robustness of general theory of skyhook control under different spring stiffness and sprung mass is researched. The results indicate that the suspension with general theory of skyhook control has superior performance and robustness compared with the traditional skyhook damper controlled suspension and passive suspension.

This piece of research aims to design and evaluate an impedance-based control for vehicle suspension on the basis of the proposed generalized skyhook-groundhook hybrid strategy. Different from classical impedance control, the proposed impedance-based control optimizes and generalizes the skyhook-groundhook structure from the perspective of complex domain mechanical impedance. A controllable inerter is designed and its nonlinearity is identified based on the bench experiment to realize the proposed impedance-based control. The hybrid weighting coefficient of the skyhook and groundhook in impedance-based control is determined via the 95th percentile aggregate fourth-power force. The numerical analysis demonstrates that the proposed impedance-based control in the ideal model and the nonlinear model can both enhance the suspension performance in ride comfort and road friendly significantly. Furthermore, the impedance-based control can be surprisingly simple as the traditional skyhook damper control and much easier for realization than the feedback-based control strategies. In addition, the influence of nonlinearity and sprung mass on suspension performance verifies that the designed suspension can maintain stability under different working conditions. In conclusion, the impedance-based control manifests a great prospect in vibration control and provides a new design principle for the vibration control system.

As a two-terminal mass element, an inerter makes up for the lack of mass impedance in a traditional vehicle suspension system. A passive Inerter-Spring-Damper (ISD) suspension can significantly improve vibration isolation performance in a low frequency range, while the impact is not obvious in other frequency bands. To isolate a wider frequency of vibrations in a vehicle suspension system on the basis of an ISD suspension, this paper combines the concepts of using an Acceleration-Driven-Damping (ADD) approach, which can effectively suppress vibrations in medium and high frequency bands, and an ISD passive network, which is superior in low frequency bands. First, an ideal model optimization design method of an ISD vehicle suspension based on an ADD positive real network is proposed, and a secondorder model is built. The parameters are optimized by means of the artificial fish swarm algorithm considering both positive real constraints and suspension performance constraints. Then, on the basis of the optimal ideal model, a radial basis function sliding mode controller is designed to control the ISD vehicle suspension system using a mechatronic inerter. Finally, simulations and experiments are carried out to verify the dynamic performance of the proposed ISD suspension. The results show that a controllable ISD suspension system based on an ADD positive real network can improve the suspension performance effectively and isolate a wide range of frequency vibrations. This research provides theoretical evidence and methodological guidance for further enriching the design and dynamic control of ISD suspension systems.