关键词: 洗衣机, 脉冲式电磁感应, 金属异物检测, 实时监测, 弱信号处理

Abstract: Aiming at the problems of insufficient sensitivity and poor real-time performance of traditional metal foreign object detection methods in low signal-to-noise ratio scenarios caused by strong electromagnetic interference, co-mode interference and baseline drift in the operation of drum washing machines, a high-precision metal foreign object detection system based on pulsed eddy current sensing is proposed for drum washing machines. The system constructs a throw-in embedded sensor and designs a differential mutual inductance detection front-end to suppress common-mode electromagnetic interference; at the algorithm level, a three-level signal processing link of cascaded sliding average filtering-adaptive baseline correction-adaptive threshold pulse detection is proposed to realize the effective extraction of weak metal eddy current signals and adaptive threshold judgment in a strong noise background. The test results based on a certain type of drum washing machine show that the comprehensive detection rate of metal foreign objects of this system is better than 90%, which not only effectively solves the problem of electromagnetic compatibility, but also improves the safety and intelligent monitoring level in the washing process, providing a new technical path for the intelligent perception module of high-end home appliances.

Key words: Washing machine, Pulsed electromagnetic induction, Metal foreign object detection, Real-time monitoring, Weak signal processing