Contact force assignment using fuzzy logic

This paper outlines a method by which the contact forces required to apply an arbitrary wrench to a stably grasped object may be calculated quickly. The assignment of contact forces, given a required object wrench, is accomplished through the use of fuzzy logic. This concept is referred to as the fuzzy logic reactive system (FLRS). The solution is versatile with respect to goals inherent in the rule-base and the input parameters, and is also applicable for an arbitrary number of contacts. The goal presented in this paper, to illustrate the basic concept of the FLRS, is the minimization of the norm of the contact forces using point contacts with friction. Results comparing the contact force assignment for this method and a numerical approximation of the optimal method proposed by Nakamura are given. The results show that FLRS will satisfy the object wrench and frictional constraints while achieving near optimal contact force assignment. This method is shown to require significantly fewer floating point operations than the solution calculated using numerical constrained optimization techniques