Experimental Investigation on the Lumped Model of Nonlinear Rocker–Rocker Mechanism With Flexible Coupler

The nonlinear and flexible effects on the continuum dynamics of rocker–rocker flexible mechanism are investigated. An experimental rocker–rocker mechanism with flexible coupler was first established. The flexible mechanism which incorporats the buckling motion of flexible coupler is acted as a double-well oscillator. The mechanism was actuated by electromagnet and measured by charge-coupled device (CCD) visual system. Rich dynamic behavior such as complex period, amplitude modulation, and chaos in the intrawell and interwell oscillations were observed. For investigating nonlinear dynamics, the dynamic behavior was analyzed through identification of linear and nonlinear lumped models. Both time-domain and frequency-domain approaches were carried out in identifying linear time-invariant model. Averaging multiple models were employed for the time-domain identification of linear model. The identification of nonlinear model was undertaken by the extension of the two-stage linear identification scheme. The response identification in input space was analyzed by utilizing semi-analytical harmonic balance method. The important boundary of chaotic response in operation was investigated by the proposed energy-well criterion, Melnikov's criterion, Moon's criterion, as well as Szemplińska-Stupnicka and Rudowski's criterion.