Active control method for vehicle suspension based on the mechanical characteristics of large-scale zero-stiffness vibration isolator

People have high requirements for the comfort of vehicle riding, so active suspension control has always been a research hotspot. However, due to the difficulty in obtaining speed signals, the implementation of active suspension control is extremely difficult. In this paper, a novel active control method for vehicle suspension is proposed, which is based on the mechanical characteristics of a large-scale zero-stiffness isolator. The active control force obtained by the new method is only proportional to the relative displacement between the tire and the vehicle body, which is easily achievable in practical applications. Firstly, a physical model of a novel large-scale zero-stiffness vibration isolator is developed, and its segmented force characteristics are derived. Subsequently, the force characteristics between the tire and the vehicle body are integrated with the segmented force characteristics of the isolator to generate the active control force for the 2-degree-of-freedom (2-DOF) quarter vehicle active suspension model. Then, an analysis was conducted to demonstrate that the proposed active control method can maintain stability of the vehicle suspension system. Then, there representative road surfaces are selected for numerical simulation testing, and the results demonstrate the efficacy of the active control method in significantly enhancing suspension performance. In comparison to passive suspension, the vertical acceleration RMS values of the vehicle body are reduced by 76.2%, 77.8%, and 43.2% under the bump road, sine undulating road, and C-level road, respectively. Finally, to be closer to the actual situation, a new testing verification method is proposed. A multi-body dynamics model considering the existence of random nonlinear disturbances in the vehicle body is built and it is used to test the effectiveness of the control algorithm.