In the field of condition monitoring and fault diagnosis for rotating machinery, order tracking technology has become a core solution for addressing the challenge of fault identification under variable-speed operating conditions, owing to its precise analysis capabilities for non-stationary signals. As the "sensing terminal" for signal acquisition, the selection and application of sensors directly determine the accuracy and effectiveness of order tracking. The deep integration of these two technologies provides reliable support for the health management of rotating machinery, widely applied in critical sectors such as aerospace, rail transit, and industrial manufacturing.

The core value of order tracking technology lies in addressing the "frequency ambiguity" issue of traditional spectral analysis under variable-speed conditions. During the start-up, shutdown, or load fluctuations of rotating machinery, the vibration signal frequency synchronizes with the rotational speed. Traditional fixed-sampling spectral analysis leads to overlapping frequency components and blurred features, making it difficult to identify fault signals. Order tracking employs variable sampling frequency technology, ensuring the sampling rate remains an integer multiple of the rotational speed. This achieves equal-angle sampling, converting non-stationary signals in the time domain into stationary signals in the angular domain. Subsequently, FFT analysis extracts order characteristics—using the rotational speed as the base frequency, with its integer multiples representing corresponding orders, thereby precisely locating fault risks in components such as gears and bearings.

Sensors, as the "data source" of order tracking technology, directly influence the accuracy of analysis results with their performance and adaptability. Based on monitoring requirements, common sensors are primarily categorized into three types, each with distinct focuses and suitability for different scenarios. The rotational speed sensor is the core of order tracking, with photoelectric encoders being the most widely used. By outputting pulse signals, they accurately capture the angular position and rotational speed of the shaft, serving as external trigger signals for equiangular sampling to achieve real-time synchronization between speed and sampling frequency, playing a key role in scenarios such as low-speed gear fault diagnosis. Vibration sensors are responsible for collecting mechanical vibration signals. Piezoelectric accelerometers, with their advantages of fast response and wide measurement range, are extensively used in vibration monitoring for equipment like gearboxes and turbines, while MEMS accelerometers are suitable for miniaturized, low-cost monitoring applications. Additionally, auxiliary sensors such as temperature and pressure sensors can supplement environmental parameter monitoring, providing more comprehensive references for order analysis and enhancing the accuracy of fault diagnosis.

The collaborative application of order tracking and sensors has been successfully implemented in various industrial scenarios. In wind turbines, rotational speed sensors capture real-time fluctuations in rotor speed, while vibration sensors collect vibration signals from the nacelle and main shaft. Order tracking technology identifies early-stage faults such as gearbox wear and bearing pitting by analyzing amplitude variations across different orders, thereby preventing unplanned downtime. In the aviation engine sector, photoelectric encoders and vibration sensors work in tandem, with order tracking capturing characteristic orders during engine start-up and acceleration phases to promptly detect hidden risks like turbine blade imbalance and misaligned couplings, ensuring flight safety. In rail transit, this combination monitors the operational status of train wheel sets and traction gearboxes, enabling early fault warnings through order spectrum analysis to reduce maintenance costs.

With the advancement of industrial intelligence, order tracking technology and sensor applications are evolving toward higher precision, integration, and intelligence. The deployment of novel fiber optic sensors and laser vibrometers has further enhanced signal acquisition accuracy and anti-interference capabilities. Breakthroughs in speedless order tracking technology have eliminated reliance on rotational speed sensors, expanding application scenarios. The deep integration of these two technologies not only enables early warning and precise diagnosis of rotating machinery faults but also drives the transition of equipment health management from "passive maintenance" to "active prevention.".

In summary, order tracking technology provides an effective method for analyzing non-stationary signals, while sensors offer high-quality data support, making the two complementary and indispensable. In the future, with advancements in sensing technology and improvements in signal processing algorithms, their collaborative application will become even more widespread, ensuring safer and more efficient operation of rotating machinery and further enhancing industrial intelligence.