Abstract：The RV reducer is widely used in industrial robots, and it has great significance to research the fault detection method of its key components. Due to the complex structure of the RV reducer, low rotating speed of the cycloidal gear, and weak fault impact etc, it is difficult to extract the fault features of the cycloidal gear using conventional vibration analysis methods. To solve above problems, a method based on encoder signals for extracting the fault features of the cycloidal gear in RV reducer is proposed. Firstly, the encoder angle signals are collected, and then the instantaneous angular velocity signals are obtained using the forward difference method. Based on this, the angular domain synchronous averaging is used to extract the cycloidal gear period-related synchronous components, eliminate asynchronous interference, and select the gear harmonics frequency bands with rich fault information by constructing a sideband signal-to-noise ratio index for bandpass filtering. Finally, the filtered signal is narrowband demodulated to achieve fault feature extraction of the cycloidal gear in the RV reducer. Experimental results show that this method can effectively extract the fault features of the cycloidal gear in the RV reducer, and achieve adaptive optimization of bandwidth selection.
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