Direct Collocation for Dynamic Behaviors With Nonprehensile Contacts: Application to Flipping Burgers

To realize robotic systems in real-world settings, e.g., in restaurants, it will be necessary to achieve dynamic manipulation of nontrivial objects. In this context, this letter discusses methodologies used to realize trajectories in a robotic arm platform, specifically, applied to flipping burgers as an example of nonprehensile object manipulation. Flipping of burgers involves a series of tasks-going to the burger location, scooping, picking up, and flipping. Since the goal is to obtain these trajectories in a reasonably fast manner, we employ direct collocation based multisegmented trajectory optimization. We will first describe the problem setup, and then describe the constraints, decision variables employed, and then, to conclude, we will demonstrate these behaviors in a 6-DOF robot experimentally.