## 1 Introduction  
In modern agricultural systems, the drying of crop grains is a critical step in preserving quality and extending storage life [1]. Due to the high moisture content of freshly harvested crops, prompt drying is essential to prevent mold growth [2]. The inadvertent use of -modal-contaminated grains in food processing not only compromises their nutritional and functional value but may also result in the production of aflat under favorable conditions [3], posing significant risks to human health. Furthermore, contamination can markedly reduce the germination rate of seeds, thereby impeding subsequent agricultural production [4]. Therefore, timely dehydration and drying are essential to lower grain moisture content, improve storage and transport stability, and maintain grain quality and germination viability--key objectives in post-harvest crop management. Traditional drying methods typically involve placing grains on trays within a drying chamber, where hot air is circulated to facilitate moisture removal [5]. However, this approach presents several limitations. [PERSON] et al. [6] reported that an extended stationary placement of grains on trays during drying can result in localized overheating (scalding), which degrades grain quality. Additional studies [7] have shown that temperature gradients develop between the ray-contacting surface of the grain and the exposed surface, leading to non-uniform heating. This discrepancy often results in uneven internal moisture distribution and structural damage, such as endosperm rupture. Previous investigations [8] also revealed that frequent opening of the oven door during the drying process destabilizes the internal temperature and prevents the real-time monitoring of grain weight. As a consequence, it becomes challenging to quantify moisture loss accurately, often leading to issues such as grain discoloration or burning. These limitations hinder drying efficiency and adversely affect crop yield and economic returns. To address the limitations of traditional drying methods, researchers have begun to explore more efficient and intelligent drying technologies. Among these, vibratory heating has garnered significant attention due to its distinct advantages [9]. [PERSON] et al. [10] introduced a vibration module within the drying tray to induce continuous grain motion during the drying process. This transient separation from the tray surface effectively mitigated the risk of scaling caused by prolonged contact. Building on this foundation, the integration of piezoelectric detection technology offers further optimization of the drying process. This technology enables the real-time monitoring of both the vibration module's operational state and the dynamic behavior of the grains, allowing the precise regulation of vibration frequency and amplitude to ensure uniform and efficient drying. Piezoelectric sensors are integral to such systems [11]. Previous studies [12] have demonstrated that the mechanical stress generated from grain collisions induces charge output due to changes in material properties. This weak electrical signal is then amplified via a charge amplifier and converted into a measurable voltage signal. These voltage outputs encapsulate critical vibrational parameters--including frequency, amplitude, and phase--that reflect the dynamic state of the system during operation [13]. By analyzing these signals, it becomes possible to implement real-time monitoring and control of the heating-vibration process, thereby providing a robust basis for the optimization of drying parameters [14]. Moreover, earlier research [15] has shown that different grain types and qualities generate distinguishable vibration response signals. For example, [PERSON] et al. [16] utilized time-domain signal features such as voltage amplitude and specific frequency to differentiate between grains and impurities in mixed samples. By constructing corresponding signal feature models, [PERSON] et al.