Robotic Assembly of Rounded Parts With and Without Threads

Artikel i vetenskaplig tidskrift, 2020

This letter addresses the assembly of rounded parts with and without threads, which is considered as the backbone of several types of assembly, and proposes novel human-inspired strategies for the hole-in-peg and nut-in-screw assemblies. These strategies employ force/torque (F/T) measurements provided by a F/T sensor and consist of two phases, namely adjustment and alignment. The proposed solution is based on quasi-static models and on the concept of attractive region in environment, and it is implemented using active force control on a velocity-controlled manipulator to avoid damages in the manipulator or in the environment. The experiments using mechanical parts with narrow tolerances show a high success rate and performance, where relatively large position and orientation errors are dynamically eliminated.