Reduction of the End Effector Sensitivity to the Structural Deflections of a Single Flexible Link: Theoretical and Experimental Results

Abstract

The fine positioning problem of the gripper of flexible robotic manipulators is addressed in this study. A two-axis cartesian micro-manipulator is implemented to reduce the sensitivity of the gripper to the structural deformations of a single flexible link. A laser head with a dual axis photodetector are used to provide direct measurements of the transverse deflections at the free-end of the beam and to detect mechanical inaccuracies caused by manufacturing imperfections and assembly misalignment. The advantages of the integrated system of the micro-manipulator with a single compliant beam are demonstrated and compared to the one without the micro-manipulator for two different control schemes, “rigid body controller (RBC)” and “rigid and flexible motion controller (RFMC).” Both theoretical and experimental results have proven the capability of the micro-manipulator in significantly improving the gripper positional accuracy. Furthermore, it was demonstrated that the micro-manipulator tends to complement rather than overlap the efforts exerted by the host beam controller.