An Algorithm for Seam Tracking Applications

Abstract

Seam tracing is currently accomplished by exploiting special features of the robot and a priori knowledge of the seam geometry. This paper demonstrates the feasibility of tracking a seam in real time. A general-purpose seam tracing algo rithm is developed for implementation on a robot with six de grees of freedom. The algorithm is motivated by a physical interpretation of the T₆and d T₆matrices and the assumption that three-dimensional seam data are available. In the past, the d T₆matrix and inverse Jacobian solutions have been used to compute the differential changes in the joint angles. The inverse Jacobian is used to introduce an iterative algo rithm to compute both large and small changes in the joint variables. The versatile seam tracking algorithm can be applied to a multitude of robotic seam tracking activities such as gluing, surface grinding, and flame cutting.