electronical and mechanical system modeling of robot dynamics using a mass/pulley model

the well-known electro-mechanical analogy that equates current, voltage, resistance, inductance and capacitance to force, velocity, damping, spring constant and mass has a shortcoming in that mass can only be used to simulate a capacitor which has one terminal connected to ground. a new model that was previously proposed by the authors that combines a mass with a pulley (mp) is shown to simulate a capacitor in the general case. this new mp model is used to model the off-diagonal elements of a mass matrix so that devices whose effective mass is coupled between more than one actuator can be represented by a mechanical system diagram that is topographically parallel to its equivalent electric circuit model. specific examples of this technique are presented to demonstrate how a mechanical model can be derived for both a serial and a parallel robot with both two and three degrees of freedom. the technique, however, is extensible to any number of degrees of freedom