Authors: Gürsel ALICI, Sedat BAYSEÇ
Abstract: This paper presents the results and implications of our study into the influence of inertial and geometric parameters on the position tracking of compliant robot manipulators where the main source of compliance is the elasticity of their joints. An R-R joint rigid link manipulator with elastic joints is considered as a case study. The equations of motion based on the deviations from the desired joint positions due to the elasticity of the joints are derived for the manipulator; the deviations are considered as the outputs and the joint positions and their second derivative as the inputs. The equations are solved on a digital computer for two classes of inputs: (1) the joint positions and accelerations corresponding to a circle which is traced by the manipulator end point with a constant tangential end point velocity, and (2) the position and acceleration of each joint, which are based on a jerk-free cycloidal displacement function. The system is simulated for various inertial and geometric parameters under open-loop control. We employa performance criterion, which we call absolute joint position deviation, in order to compare various simulation results. The simulation results demonstrate that it is possible to minimise position tracking error by taking certain precautions during design stage before employing advanced control/compensation techniques. This allows us to model and control a flexible joint manipulator as a rigid manipulator.
Keywords: robot manipulator, flexible joint robot manipulator, inertial and geometric parameters, robot position control.