Bond graph representation of multibody systems with kinematic loops

In this paper we propose a procedure for building bond graph representations of multibody systems with kinematic loops. It is systematic in the sense that no analytical derivation is necessary to construct the bond graph. It also gives a more graphically and analytically exploitable representation compared to the Tiernego and Bos procedure. Our method first considers the kinematic loops globally before building the body bond graphs. Therefore we have to detect a privileged frame for each kinematic loop in which we can express the kinematic constraint. Then we construct the corresponding junction structures of bodies whose variables are projected onto those privileged frames. After having presented criteria and a method for selecting the latter, two examples are given: the forming machine and the flyball governor.