Wan Zhou

Application of Wavelet Packet and Hilbert Operator to the Fault Diagnosis of Rolling Bearing

The fault signal of rolling bearing has the feature of nonstationarity. To apply wavelet packet to decompose and reconstruct the vibrational signals collected from testing at first, then the Hilbert operator was applied to achieve the purpose of demodulating the envelope. Finally, the signals after refining envelope spectrum will expand the information of defects. And then extracting the characteristic frequency of fault signals and judging the fault location of the bearing. The experimental analysis shows that wavelet packet and Hilbert operator could be applied to extract the characteristic defect frequency of rolling bearing effectively, and in the other word this method is effective to detect the class of local damage of rolling bearing.

Simulink Simulation of Single Neuron PID and Smith Predictive Control Based on the s-Function

Aiming at nonlinearity and large dead-time of object to enhance dynamic quality of closed-loop system, this paper applies single neuron PID controller based on supervised Hebb learning algorithm, combined with correction of actual weighting coefficient, utilizes adaptive and self-learning ability of single neuron, tunes weights of controller and compensate for delay time, in order to improve its dynamic quality of closed-loop system. The simulation result shows that the method given in this paper can achieve good control characteristic and eliminate the impact on dynamic quality of system caused by delay time.