Characteristics and experimental research on semi-active suspension of mining dump truck under parallel fuzzy control strategy

The traditional passive hydro-pneumatic suspensions installed on mining dump trucks is hard to adapt the complex roads, while the active suspension system can’t be spread and used widely because of its higher costs and external supply requirements. Therefore, semi-active suspension system is increasingly applied in engineering vehicles due to its simple structure and adjustable damping characteristics. This paper introduces a semi-active suspension system based on high-speed on–off valve control capable of switching among four distinct damping modes. Based on suspension design theory and principles, the structure of the damping switcher is defined, and a damping characteristic model for the semi-active suspension is developed. Then, a four-degree-of-freedom vehicle dynamics model was established. A fuzzy control strategy, considering both the ride comfort index and stability index, was designed using MATLAB/Simulink. With suspension dynamic travel and body pitch angle as the input of the controller, the weight integral rule is formulated according to the road level to process the output signal of the fuzzy controller, and two on–off valve control rules are obtained. The filtered white Gaussian noise is used as random road excitation for simulation. Additionally, a suspension system test platform was constructed. Compared to traditional passive suspensions, the root mean square (RMS) of vertical vibration acceleration of the semi-active suspension decreases by 14.8%, 16.9%, and 19.3% on A, B, and C road classes, respectively. The RMS of peak pitch angle decreases by 17.1%, 15.7%, and 13.6%, respectively. Experimental results are basically consistent with the simulation findings, demonstrating the effectiveness of the semi-active suspension and the fuzzy control strategy. This provided consolidated experimental and theoretical basis for vehicle dynamics, effectively enhancing vehicle ride comfort under challenging operating conditions.