Abstract: The propagating principle of torsional elastic wave and response in the shaft system is studied by means of elastic wave propagation theory. The transmissions of elastic wave in varying cross-section are considered. The vibration displacement amplitude at the error sensor is as cost function. The optimal position of secondary source and the error sensor are determined. The theoretical simulation and experimental investigation on active control are evaluated in one-stepped shafts. The results show that the active control of torsional wave could be successfully achieved by the feedforward controller with single control source and a single error sensor for any complicated multi-stepped shafts.

Key words: Active control, Stepped shaft, Torsional elastic wave