Dynamic Simulation of a Mobile Manipulator with Joint Friction

Mission criticality in disaster search and rescue robotics highlights the requirement of specialized equipment. Specialized manipulators that can be mounted on existing mobile platforms can improve rescue process. However specialized manipulators capable of lifting heavy loads are not yet available. Moreover, effect of joint friction in these manipulators requires further analysis. To address these issues, concepts of model based design and concurrent engineering are applied to develop a virtual prototype of the manipulator mechanism. Closed loop manipulator mechanism actuated by prismatic actuators is proposed herein. The mechanics model of the manipulator is presented here as a set of equations and as multibody models. Mechanistic simulation of the virtual prototype has been conducted and the results are presented. Combined friction model that comprises Coulomb, viscous and Stribeck friction is used to compute frictional forces and torques generated at each one degree of freedom translational and rotational joints. Multidisciplinary approach employed in this work improves product design cycle time for complex mechanisms. Kinematic and dynamic parameters are presented in this paper. Friction forces and torques from simulation are also presented in addition to the visual representation of the virtual prototype.