Divide-and-Conquer-Based Method for the Reaction Uniqueness Analysis in Overconstrained Multibody Systems

摘要: In the modeling and simulation of complex mechanical or robotic systems, the method of multibody systems (MBSs) is very useful since it enables full automation of calculations. In the basic approach, a mechanism is modeled as a system of rigid bodies forming kinematic pairs. The system is subjected to kinematic or force inputs. A special but often encountered class of MBSs are mechanisms with redundant constraints. The introduction of redundant constraints into the system is usually the result of a conscious decision of the designer, made after considering the advantages (eg, greater system strength) and disadvantages (eg, the requirement for greater accuracy of system parts and the introduction of assembly stresses). Modeling such mechanisms is difficult, and one of the main problems is the nonuniqueness of some reaction forces.The essence of the problem is that the results of numerical simulations may, in some cases, differ from reality. The physical (in the sense of real) reactions of the system are always defined (although they are not always easy to measure or calculate). Therefore, the described problem of nonuniqueness is related only to mathematical models of MBSs. In the case of overconstrained systems, it is impossible to determine all generalized reaction forces [1], and thus also physical reactions in kinematic pairs.