Modeling and Simulation of the Dynamics of the Quick Return Mechanism: A Bond Graph Approach

This paper applies the multibond graph approach for rigid multibody systems to model the dynamics of general spatial mechanisms. The commonly used quick return mechanism which comprises of revolute as well as prismatic joints has been chosen as a representative example to demonstrate the application of this technique and its resulting advantages. In this work, the links of the quick return mechanism are modeled as rigid bodies. The rigid links are then coupled at the joints based on the nature of constraint. This alternative method of formulation of system dynamics, using Bond Graphs, offers a rich set of features that include pictorial representation of the dynamics of translation and rotation for each link of the mechanism in the inertial frame, representation and handling of constraints at the joints, depiction of causality, obtaining dynamic reaction forces and moments at various locations in the mechanism and so on. Yet another advantage of this approach is that the coding for simulation can be carried out directly from the Bond Graph in an algorithmic manner, without deriving system equations. In this work, the program code for simulation is written in MATLAB. The vector and tensor operations are conveniently represented in MATLAB, resulting in a compact and optimized code. The simulation results are plotted and discussed in detail.