Speed Control of a 2-DOF Reciprocating Machine Using a Virtual-Vibration-Absorber Algorithm

Abstract

A two-axis reciprocating machine, termed Complementary Scotch Yoke (CSY), is regulated via a novel control algorithm. Containing two independent driving motors, it is capable of converting two-axis rotary movements into double-mode linear harmonic motions. The axes are subject to periodic disturbances of quadruple characteristic frequencies when the machine undergoes harmonic motions. A feedback law emulating multi-mode vibration absorbers is designed to compensate for the periodic disturbances so that the driving axes are regulated at the set angular speeds. The virtual passive controller ensures stability of the unforced system, and it is shown that the periodic disturbances can be canceled out if the virtual vibration absorber has all of the characteristic frequencies of the disturbance. Experimental results on a CSY prototype confirm the effectiveness of the proposed method.