BONDGRAPH MODELLING OF ROBOT DYNAMICS

Euler-Lagrange and Newton-Euler dynamic modelling become very involved and the equations quite complex even for a robot of few axes. For robot models, the bondgraph approach provides several advantages such as explicit bondgraph representation of the robot physical parameters and does not involve any complex equation writing or matrix inversion. In this paper, the use of the bondgraph method for modelling and simulating robot dynamics is presented. To illustrate the technique, a dynamic model for a SCARA robot is derived using bondgraph modelling. The causality conflict arising from the dependent inertias is solved by introducing structural and joint damping. Simulation results obtained using the developed model were in very close agreement with the analytical values obtained using the manipulator kinematic relations. Response due to impact excitation was obtained and is presented.