Using Redundancy in Serial Planar Mechanisms to Improve Output-Space Tracking Accuracy

Abstract

Path tracking using planar mechanisms with one degree of redundancy can be enhanced by matching (when possible) or approximating second-order path properties with first-order joint coordination. Second-order tracking can reduce the frequency of feedback for the desired accuracy, and since this paper provides analytical expressions for the joint speed ratios, this advantage comes at no additional computational cost. Examples show that tracking solutions with thismethod are locally more accurate compared to unweighted pseudoinverse solutions. Therefore, the feedback frequency for a desired tracking accuracy can be reduced, potentially resulting in a reduced computational cost of path tracking.