Characterization of Constraints in Flexible Unknown Environments
This work addresses the challenge of enabling robots to safely manipulate elastic systems without prior knowledge, with potential applications in domains like surgical organ retraction, though it appears incremental in advancing existing constraint exploration methods.
The paper tackles the problem of safe autonomous manipulation of flexibly constrained objects in unknown environments by presenting an online path planning algorithm that identifies and characterizes flexible constraints in real time, demonstrating the ability to recognize common mechanical constraints and identify relevant screw parameters through simulation and experimental validation.
This paper presents an online path planning algorithm for safe autonomous manipulation of a flexibly constrained object in an unknown environment. Methods for real time identification and characterization of perceived flexible constraints and global stiffness are presented. Used in tandem, these methods allow a robot to simultaneously explore, characterize, and manipulate an elastic system safely. Navigation without a-priori knowledge of the system is achieved using constraint exploration based on local force and position information. The perceived constraint stiffness is considered at multiple poses along an object's (system) trajectory. Using stiffness eigenvector information, global stiffness behavior is characterized and identified using an atlas of simple mechanical constraints, such as hinges and planar constraints. Validation of these algorithms is carried out by simulation and experimentally. The ability to recognize several common simple mechanical constraints (such as a flexible hinge) in real time, and to subsequently identify relevant screw parameters is demonstrated. These results suggest the feasibility of simultaneous global constrain/stiffness exploration and safe manipulation of flexibly constrained objects. We believe that this approach will eventually enable safe cooperative manipulation in applications such as organ retraction and manipulation during surgery