Research And Development On Full-spectrum Dynamic Balancing Measurement Svstem Based On Smart Mobile Terminal

Whole dynamic balancing is the key technique for vibration control of rotating machinery, at present, most of whole dynamic balancing are carried out based on single directional vibration information in industry, but to rotor system of anisotropic rigidity, the single balancing accuracy and balancing effiecincy of above methods is very low.Besides,the instruments of dynamic balancing based on above method are usually handhold equipment whose core is MCU or field measurement system that PC is acted as upper machine and MCU is used as lower machine. The former has weak data processing ability and poor human computer interaction, although the latter has digital and humanized features, its high cost, relatively poor endurance power, inconvenient portability and long and redundant wiring limit its application. To solve above disadvantages, after studying principle of the full-spectrum whole machine dynamic balancing method deeply, the design and development of full-spectrum whole dynamic balancing measurement system are discussed in detail from hardware framework, communication protocol and software implementation.The concrete research achievements are as follow:1. This paper proposes full-spectrum whole dynamic balancing method.First. the reference signal and the vibration signals from from the X and Y components of the rotor are pick up, and the amplitude and phase of working frequency vibraton are achieved with integral period cross correlation method, next,combined with the FFT and holospectral technique, the working frequency fault diagnosis is diagnosed accurately. Then, the rotational frequency ellipse is decomposed into forward and reverse circle orbits,and the discovery that initial vector of forward orbit can represent the unbalance vibration response of anisotropic rotor is verified by simulation and experiments,and the study shows that the rotor’s unbalance can be identified with influence coefficient method based on initial vector of forward orbit.2. The new type of measurement system with the structure of "Android phone+Bluetooth module+MCU" for full-spectrum whole dynamic balancing is put forward. This system adopts master-slave structure, and the upper machine uses Android mobile phone for human-computer interaction, vibration monitoring, fault diagnosis, unbalance iedntification and data storage, and the lower machine mainly consists of MCU to complete signal acquisition, and the Bluetooth module shoulders the responsibility to convert the serial signal to the Bluetooth RFCOMM data format.The communications between upper and lower machine are achieved through wireless Bluetooth.3. This paper designs the communication protocol between the upper and lower machine and succeeds in completing the whole software implementation of dynamic balancing measurement system. The Bluetooth RFCOMM channel connection between the two is built and reliable communication is realised, at the same time, the real-time vibration monitoring, vibration analysis, unbalance identification and data storage on phone are implemented.4. The dynamic balancing experiments on 4-72 type centrifugal fan have been carried out with the developed instrument and good balancing effects are obtained, and results indicate:compared with traditional influence coefficient method, the full-spectrum dynamic balancing method has higher single balancing precision and more effective balancing efficiency, and the proposed balancing method and the developed instrument are reliable and feasible.