A Measurement Device for the Dynamic Unbalance of Crankshaft

This article introduces a measurement device we have developed by ourselves-its hardware principles and software structures. This system has already been used on production lines of crankshafts. The hardware comprises industrial control computer, A/D conversion circuit, two-path performance-symmetrical signal adjusting circuit (includes two pressure transducers, charge amplifiers, filters etc) and the composition of formation circuit of the reference signal consistent with the rotating velocity. Since the dynamic unbalance signal is totally submerged in the strong noise, for the sampled signals, a software has been used to implement such operations as median filtering, average value filtering, cross correlating operation, digital correction etc. so as to get the real dynamic unbalance signal. In reality, it is proved that the measured effects of it are pretty good, the minimum residual value of unbalance can achieve Umar 91% per plane.