Error analysis and correction for high-precision parallel robots

Abstract

Mechanism manufacturing errors in a 6-HTRT parallel robot were analyzed to reduce mechanism end errors and enhance high-precision parallel robot motion accuracy. A Hooke's joint was developed with a pre-strain set in the parallel robot. Digital signal processing was used in the control system. The mechanism end errors were corrected by using the vector construction method to calculate the mechanism velocity Jacobian matrix, using numerical methods to calculate position forward solutions, and using the construction method to calculate error Jacobian matrix. The result shows that the system precision is increased to three times the mechanism repeat motion precision, which meets the high-precision parallel robot precision requirements. The software based error correction method is not confined to only parallel mechanisms but can be for a wide range of mechanisms.