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Joint RV speed reducer weak fault identification method

A technology of reducer and weak fault is applied in the field of intelligent fault diagnosis and health assessment of industrial robots, which can solve the problems of difficult acquisition of key phase pulses and inability to accurately feedback joint operation status.

Pending Publication Date: 2021-09-17
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The conventional way to obtain the speed of the servo motor is to analyze the key phase pulse signal of the encoder, but for the robot, the key phase pulse is not easy to obtain, and it is impossible to accurately feedback the real operating state of the joint

Method used

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  • Joint RV speed reducer weak fault identification method
  • Joint RV speed reducer weak fault identification method
  • Joint RV speed reducer weak fault identification method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Example 1: Fault Analysis of Cracks in Planetary Gear Root of Joint RV Reducer

[0046] Using RV-40E reducer, figure 1 It is a schematic diagram of the RV reducer test bench for simulating joint motion, which includes 1-swing arm, 2-servo motor, 3-accelerator sensor, 4-RV reducer, 5-test bench base, 6-current transformer, 7-electric Cabinet; experimental preset: the range of motion of the swing arm is 100°~180° (80° for a single cycle, 160° for a single cycle of rising and falling), and the operating speed of the swing arm is 32° / s. The specific operation process is as follows:

[0047] 1. During the rising process of the swing arm, use the current transformer 6 to obtain the current signal I(t of the servo motor 2 1 ),Such as figure 2 As shown; Acceleration sensor 3 is used to obtain the vibration signal S(t 2 ),Such as image 3 Shown; t 1 is the current signal I(t 1 ) sampling time and t 2 is the vibration signal S(t 2 ) at the sampling moment; the current si...

Embodiment 2

[0061] Embodiment 2: The method for weak fault identification of the joint RV reducer is as follows:

[0062] Using the RV-40E reducer, the schematic diagram of the joint motion RV reducer test bench in this embodiment is the same as that in embodiment 1, the difference is that the joint RV reducer has no faults, and the running speed is different, the sampling rate is different, and the swing arm running speed is 45° / s ;

[0063] 1. During the rising process of the swing arm, use the current transformer 6 to obtain the current signal I(t of the servo motor 2 1 ),Such as Figure 13As shown; Acceleration sensor 3 is used to obtain the vibration signal S(t 2 ),Such as Figure 14 Shown; t 1 is the current signal I(t 1 ) sampling time and t 2 is the vibration signal S(t 2 ) at the sampling moment; the current signal is collected as the U-phase current signal at the output end of the driver, and the sampling frequency is 8192Hz; the vibration signal is collected as the posit...

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Abstract

The invention discloses a joint RV speed reducer weak fault identification method. The method comprises the steps: asynchronously collecting servo motor current signals of robot joints and vibration signals of the running state of a joint RV speed reducer; taking a time point corresponding to the maximum rotation frequency in a time-frequency diagram of the joint current signals as a time starting point, finding out and intercepting a vibration signal in a peak stable stage from the filtered vibration signals, through cepstrum analysis, when a spectral line with a sharp amplitude value appears in a cepstrum, judging that the joint RV speed reducer has a fault, and judging whether the joint RV speed reducer has the fault or not; after judging whether the fault exists or not, carrying out variational mode decomposition analysis on the vibration signals with faults to obtain component signals of the vibration signals; and taking information entropy as a selection index, selecting reconstructed signals from the component signals, carrying out Fourier transform on the reconstructed signals to obtain a fault signal spectrogram, extracting fault features from the spectrogram, and carrying out fault type identification on weak faults. The method is simple and effective; and the method is suitable for early fault diagnosis of equipment.

Description

technical field [0001] The invention relates to an application of cepstrum analysis and variational mode decomposition in weak fault identification in a joint RV reducer, and belongs to the technical field of intelligent fault diagnosis and health assessment of industrial robots. Background technique [0002] Industrial robot research is developing towards high precision, high speed, multi-axis and light weight. The reducer is the core component of the industrial robot, and its health determines the execution efficiency and precision of the industrial robot. High-precision RV reducer (rotate vector reducer) has become the most commonly used reducer for industrial robots due to its small size, large transmission ratio, and high efficiency. In the process of long-term operation, due to the natural wear and fatigue life of parts and even sudden braking, weak faults will occur in the joint RV reducer. Because weak faults do not affect the joint operation and there is no obvious...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01M13/028
CPCG01M13/028Y02T90/00
Inventor 周俊徐天贇柳小勤伍星刘韬刘畅
Owner KUNMING UNIV OF SCI & TECH