Aimed at remedying the shortage of an effective and fast algorithm for fault diagnosis of gearboxes

a method based on approximate entropy（ApEn） is addressed.To begin with

the ApEn is introduced.Subsequently

the gearbox

on which the slight-worn

medium-worn and broken-tooth faults is simulated.Furthermore

the results show that the ApEn can successfully identify the faults of gearboxes and accurately describe the defective condition changes of gearboxes.So

ApEn is suitable for as characteristic parameter of gearbox fault diagnosis a novel and feasible method for condition monitoring and fault diagnosis of gearboxes is provided.