Incremental Kinematic Analysis of Mechanisms

Abstract

Kinematic design is an important aspect of the design of mechanical systems with moving parts. The performance of such systems may suffer from the presence of parts that bind during their motion causing jams, or that execute undesired motions. Kinematic analysis needs to be conducted and the design of the system modified. Analysis-redesign-reanalysis cycles are common in reaching a satisfactory design. If the system is large and the incidence of redesign frequent, then it becomes imperative to have fast analysis methods. This work addresses this problem by providing computational techniques for doing incremental kinematic analysis. The mechanism is represented as a graph of objects with connection constraints among them. A recursive procedure traverses the graph to establish instantaneous kinematic properties. A store-and-reuse strategy is employed to increase the efficiency of re-analysis runs. This involves storing intermediate results of computations for reuse in case of incremental redesign or iterative analysis. The store-and reuse strategy is also applicable when retrieving elements of previous designs, and their associated kinematic analyses, and adapting them to new design problems. A comparative, quantitative study of the normal, “from-scratch” method and the incremental method is provided to prove the greater efficiency of the latter.