The figure shows a schematic of a proposed variable-rate air spring capable of continuous variation. It is installed as a suspension element in the figure. It consists of a primary air cylinder coupled to a secondary cylinder with a motion-driven piston. If the piston is moved forward and mass is transferred from the front chamber to the rear chamber, then the vehicle mass will be suspended on a stiffer air spring, and the ride height will not have changed. Construct a bond graph model of this system, including all the dynamics suggested in the figure. Assign causality to show that formulation will be straightforward. This model could be used to test control strategies for an adaptive suspension.
