On Actual Motion of Planar Closed-Chain Five-Bar Underactuated Mechanism at Given Position

At any position of a underactuted mechanism, its actual motion is determined not only by the traditional forces, but by inertia force and inertia moment as well. The impact of inertia force and inertia moment is focused on in this paper. Using acceleration energy to represent the inertia force and inertia moment, and applying Gauss’s principle, the actual motion of a underactuated mechanism can be determined by means of optimization technique. A planar closed-chain five-bar underactuated mechanism is taken as an example to demonstrate this analysis method. The results show that the actual motion of the mechanism appears stochastic with respect to the variation of its position.