Reaction Based Grasp Force Assignment

An iterative method is developed by which the contact forces required to apply an arbitrary wrench (six elements of force and moment) to a stably grasped object may be calculated quickly. The assignment of contact forces, given a required object wrench, is accomplished with 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 rulebase and the input parameters, and is also applicable for an arbitrary number of contacts. The goal presented in this research, to illustrate the concept of the FLRS, is the minimization of the norm of the contact forces using point contacts with friction. The results comparing the contact force assignment for this method and the optimal method proposed by Nakamura are presented. The results show that FLRS will satisfy the object wrench and frictional contacts 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