A model free robot control method for dragging an object on a planar surface by applying top contact forces

摘要

In this work, a robot control method is proposed for dragging an object by applying top contact forces under unknown friction and object dynamics. This is a non-prehensile manipulation of an object that can enhance the grasping capabilities of a robotic manipulator in a plethora of grasping scenarios. In the proposed method, an initializing controller generates reference contact force trajectories until a desired contact motion status is achieved that enables dragging the object without slippage of the robot tip. Based on these forces, a sufficient Virtual Friction Cone (VFC) is calculated which allows proper position control of the object with no further slippage of the robotic tip. The proposed method is validated via simulations, where contact forces are simulated with the elasto-plastic friction model, and experiments with a KUKA robot dragging a variety of objects with different dynamics and surface friction.