The control difficulty will rise if the three-link acrobot uses a motor driver without torque-driven mode, but it’s
of practical. A simplified dynamic model composed of body dynamic and motor driven model based on “quasi-equivalen”
method is presented to solve the modeling problem of such a robot. The body dynamic function is constructed by using
Lagrange function. The order of acceleration driven model is identified by the Bode Plot via frequency response based
modeling method, and the pure delay is added according to the acceleration response curves. The variables of the model
are identified by using a modified generation algorithm(GA). Experiments show the effectiveness and superiority of the
simplified model.