Research Of Unbalance Identification For Dual-shaft System With Slight Speed-difference

Unbalanced vibration signal of dual-shaft rotating system with slight little-speed difference is a composite signal called "beat", how to distinguish two rotor's unbalance weight from "beat" separately is the key of balancing for this rotating system. This paper is based on State Science Project "Fast Identification Method for Unbalanced Weight of Synchronous Dual-rotor with Little Speed Difference" (ID: 50605054), an experimental device for dual-rotor system is developed and its dynamic is analysed. After a detailed analysis of whole-beat correlation method, a non-whole-beat method for separating two rotor's unbalanced weight from beat is proposed. For the characteristics than current dual-rotor system can be synchronized, a new dynamic-balancing method though synchronous rotation is proposed. A measurement system is developed based on this new method. From the experiments on horizontal decanter centrifuge and on experimental device, some important and creative conclusions are achieved as follows:1. For some dual-rotor system that cannot synchronized but its inner and outer rotor's basis signal can be achieved, a correlative method that need very short integral time is proposed. To separate two rotor's unbalanced weight from beat, the whole-beat correlative method need a beat period at least, however, the non-whole-beat correlative method can select integral time freely, so it can reduce the amount of data processing significantly, which can reduce hardware requirment for developing dynamic-balance device. This method is proved to be feasible through simulation and experiments.2. For some dual-rotor system that can be synchronized, a new dynamic-balancing method though synchronous rotation is proposed. Through synchronous rotation with two alignment angle of inner and outer rotor, their unbalance weight can be achieved. This method doesn't need inner rotor's basis signal, and doesn't need to add try-weigh to inner rotor while on balancing, which makes the balancing process very convenient. Based on large amount of experiment, a method that using the same effect- coefficient while on synchronous rotation with different alignment angle is proposed. This method can decrease the times of starting machine and improve workefficiency.