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In order to make up for the truncation of the acoustical black hole structure during the actual machining, vibration reduction of the non-ideal acoustical black hole plate was studied by laying damping materials at the bottom. A non-ideal acoustic black hole plate model was established, and the energy focusing effect at different frequencies we r e studied. Finite element model was used to analyze the vibration suppression effect of the damping layer with different radius and thickness la id under the black hole, and the accuracy of the simulation model was verified by designing experiments. The results s how that the focal degree of vibration energy center of non-ideal acoustic black hole plate in middle and high frequency band is larger than that in low frequency band, the vibration reduction amplitude increases with the increase of damping layer area and thickness, the vibration damping effect of n on-ideal acoustic black hole plate with the same damping layer is significant with the increase of frequency. [ABSTRACT FROM AUTHOR]

In order to make the ACC system of pure electric vehicle better adapt to the complex and changeable driving environment, An ACC spacing strategy based on three-dimensional fuzzy control was proposed in this paper. The double longitudinal PID controller was designed as the upper control to obtain the expected acceleration. To complete the lower control of the ACC system, the inverse longitudinal dynamics model and motor model were established to calculate the motor output torque and braking pressure. Through the co-simulation of Simulink and Carsim, the experiments of rapid acceleration, insertion and stable following of the preceding vehicle were carried out, and the experiments were compared with the classical two-dimensional fuzzy control. The results show that the proposed spacing strategy can track the preceding vehicle well under the safe spacing, and has good adaptability to various traffic conditions. [ABSTRACT FROM AUTHOR]

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