In this paper, a new adaptive dynamic surface control strategy is proposed to deal with the uncertainty parameters of electro-hydraulic actuator and unknown external disturbances of vehicle active suspension system. A dynamic model of nonlinear vehicle active suspension is established. The adaptive parameter estimation laws are designed to estimate the uncertain parameters caused by the change of the physical characteristics of the electro-hydraulic actuator. In other words, the estimation of uncertain parameters in hydraulic system is beneficial to improve the control precision of vehicle. Nonlinear robust feedback signal is introduced to suppress unknown external disturbances. Then, this paper proposes an idea of dynamic surface in order to avoid explosion of complexity that caused by virtual control signal. The dynamic surface function replaces the derivative of virtual control signal in backstepping control, which reduces the computational complexity and improves the riding comfort. The simulation comparison shows that the presented method is effective in improving riding comfort and driving safety.

This work studies the edge-based and node-based adaptive event-triggered control (ETC) problem for multi-agent systems. The aims are to achieve asymptotic consensus, guaranteed positive minimum inter-event times (MIET) and avoiding using global information. First, an edge-based distributed ETC strategy is proposed based on absolute state information, which can achieve the desired aims but subjects to some limitations in terms of symmetric conditions and practical implementation. Then, a node-based ETC strategy is proposed based on relative state information between agents, which can overcome limitations of edge-based control and can be applied to multi-agent systems with undirected/directed communication topology. The main advantage of the proposed ETC strategies is that positive MIET can always be guaranteed by designing an auxiliary function with time-varying coefficients, meanwhile, the implementation of ETC strategy does not depend on any global information, and the node-based ETC strategy can also be used under directed communication topology. Finally, numerical examples are given to illustrate the proposed approach.

This brief presents a novel low-complexity error-surface prescribed performance control (ESPPC) for the single-rod electro-hydraulic system (EHS) subject to uncertain parameters and unknown nonlinearities. Different from existing results, the servo valve spool characteristic is considered to be nonlinear rather than linear. To solve the uncertain nonlinearities in the EHS, we propose a new control design approach by utilizing the error surface, the unknown dynamic estimator (UDE), and the prescribed performance methodology, which achieves prescribed transient and steady-state performance for the tracking error while avoiding the use of the backstepping scheme and the approximators [e.g., fuzzy systems (FSs) and neural networks (NNs)]. Moreover, to prevent the propagation of peak phenomenon induced by the UDE to the controlled system, the developed controller is appropriately saturated without impacting the prescribed performance properties of the tracking error. The stability of the EHS has been rigorously proved. Finally, extensive experimental results are offered based on a physical EHS to demonstrate the validity of the proposed approach.