Intelligent Fault Diagnosis of Gearbox Under Variable Working Conditions With Adaptive Intraclass and Interclass Convolutional Neural Network

The industrial gearboxes usually work in harsh and variable conditions, which results in partial failure of gears or bearings. Accordingly, the continuous irregular fluctuations of gearbox under variable conditions maybe increase the intraclass difference and reduce the interclass difference for the monitored samples. To this end, a new intelligent fault diagnosis method of gearbox based on adaptive intraclass and interclass convolutional neural network (AIICNN) under variable working conditions is proposed. The core of the proposed algorithm is to apply the designed intraclass and interclass constraints to improve the distribution differences of samples. Meanwhile, the adaptive activation function is added into the 1-D convolutional neural network (1dCNN) to enlarge the heterogeneous distance and narrow the homogeneous distance of samples. Specifically, the training sample subset with intraclass and interclass spacing fluctuations under variable conditions is first converted into frequency domain through the fast Fourier transform (FFT), and the designed AIICNN algorithm is employed for model training. Afterward, the testing subset is provided to the trained AIICNN algorithm for fault diagnosis. The experimental data of the planetary gearbox test rig verify the feasibility of the proposed diagnosis method and algorithm. Compared with other methods, this method can eliminate the difference of sample distribution under variable conditions and improve its diagnostic generalization.

I. Introduction

As one of the main transmission components of industrial equipment, gearboxes are widely used in helicopters, wind turbines, armored vehicles, and other equipment [1], [2]. Specifically, they usually operate in harsh environments, for instance, low speed, heavy load, and gusts, which are likely to induce critical components such as gears and bearings [1]–[3]. Partial failures have now become one of the essential research objects in the field of prognostics and health management (PHM) [1]–[3]. The operational safety of gearboxes is critical to ensure the intelligent health monitoring and operation maintenance of modern industries. To reduce economic losses and personnel injuries as much as possible, the safety and stability of industrial system should be improved [3]–[5].