Motion Planning and Inertia-Based Control for Impact Aware Manipulation

In this article, we propose a metric called hitting flux, which is used in the motion generation and controls for a robot manipulator to interact with the environment through a hitting or a striking motion. Given the task of placing a known object outside of the workspace of the robot, the robot needs to come in contact with it at a nonzero relative speed. The configuration of the robot and the speed at contact matter because they affect the motion of the object. The physical quantity called hitting flux depends on the robot's configuration, the robot speed, and the properties of the environment. An approach to achieve the desired directional preimpact flux for the robot through a combination of a dynamical system for motion generation and a control system that regulates the directional inertia of the robot is presented. Furthermore, a quadratic program formulation for achieving a desired inertia matrix at a desired position while following a motion plan constrained to the robot limits is presented. The system is tested for different scenarios in simulation showing the repeatability of the procedure and in real scenarios with KUKA LBR iiwa 7 robot.