Development of DSP-based measurement system of balancing machines

With development of small-sized and high-speed rotor of motor products, higher precision of balancing machines is demanded. Digital signal processing method of measurement system of balancing machines was studied in detail. Several methods extracting magnitude and phase of unbalance signal - digital correlation analysis, digital phase sensitive analysis, least square fit, and frequency domain methods (FFT, DFT) were presented and clarified analytically. The significance of integral periodic signal sampling was indicated. According to characteristics of tested signals of balancing machines, a digital tracking filter method was put forward, its centre frequency can be adaptive tuned consistence with rotational speed of work-piece to realize the ability of tracking unbalance signal, so that interference in tested signals can be removed effectively. Moreover, DSP and single-chip based double CPU digital measurement system has been developed. The results of simulation and application in balancing machines show that these approaches improve largely the precision of small unbalance amount and reduce the minimum ultimate unbalance amount, and increase the reliability, stabilization and anti-jamming ability of the system.