In tunnel construction with tunnel boring machines (TBMs), accurate knowledge of disc-cutter failure states is crucial to ensure efficient operation and pr

Condition-based hydraulic cylinder maintenance necessitates quantitative fault diagnostics. However, existing methods are characterized by either qualitative or limited quantitative capabilities. In this paper, a quantitative fault diagnostic method using a particle filter for hydraulic cylinders is proposed. The problem of quantitative fault diagnostics is formally formulated in a stochastic framework to assess the health/fault state, and an architecture based on joint state-parameter estimation is proposed. Through the establishment and analysis of a nonlinear dynamic model of the hydraulic cylinder, the impact of time-varying parameters on the state variables is revealed. Three fault modes of the cylinder, including friction, internal leakage, and external leakage, are theoretically identified. The proposed method allows for a simultaneous quantitative diagnosis of these three fault modes. The performance of the proposed method is evaluated using meticulously designed experiments. The results demonstrate that the mean absolute percentage errors in the parameter estimations are below 9% (accuracy exceeding 91%), thus validating its feasibility and effectiveness.

In this paper, a novel electro-hydraulic braking system of low-floor vehicle is developed. Theoretical models of the three-way proportional pressure reducing screw-in cartridge valve and electro-hydraulic braking system are obtained. A system design criterion is established based on the analysis of the three-way proportional pressure reducing screw-in cartridge valve. A switched adaptive fuzzy proportional–differential–integral controller is proposed to reduce the effect of change in the reference input. The performances of the proposed controller are compared with the adaptive fuzzy proportional–differential–integral controller and conventional proportional–differential–integral controller. Numerical simulation and experimental test are conducted to demonstrate the effectiveness of the models and the proposed controller.