Collaborative Multi-Robot Transportation in Obstacle-Cluttered Environments via Implicit Communication

Abstract

This paper addresses the problem of cooperative object transportation in a constrained workspace involving static obstacles, with the coordination relying on implicit communication established via the commonly grasped object. In particular, we consider a decentralized leader-follower architecture for multiple mobile manipulators, where the leading robot, which has exclusive knowledge of both the object's desired configuration and the position of the obstacles in the workspace, tries to navigate the overall formation to the desired configuration while at the same time it avoids collisions with the obstacles. On the other hand, the followers estimate the object's desired trajectory profile via novel prescribed performance estimation laws that drive the estimation errors to an arbitrarily small predefined residual set. Moreover, a navigation function-based scheme is innovatively combined with adaptive control to deal with parametric uncertainty. Hence, the current state of the art in robust motion planning and collision avoidance is extended by studying second order non-linear dynamics with parametric uncertainty. Furthermore, the feedback relies exclusively on each robot's force/torque, position as well as velocity measurements and no explicit information is exchanged online among the robots, thus reducing the required communication bandwidth and increasing robustness. Finally, two simulation studies clarify the proposed methodology and verify its efficiency.

Mutli-Robot Cooperative Object Transportation with Guaranteed Safety and Convergence in Planar Obstacle Cluttered Workspaces via Configuration Space Decomposition

“…In this work, we generalize our previous effort [36] by presenting a methodology for coordinating the transportation of an object that is rigidly grasped by a team of mobile manipulators, which operate within a compact planar workspace with obstacles of arbitrary shape. Owing to the object rotation and the manipulators' motion, our scheme takes into consideration the varying configuration of the robotic system, as opposed to [36], in order to build a plan that can safely drive the robotic system to the goal configuration.…”

“…In this work, we generalize our previous effort [36] by presenting a methodology for coordinating the transportation of an object that is rigidly grasped by a team of mobile manipulators, which operate within a compact planar workspace with obstacles of arbitrary shape. Owing to the object rotation and the manipulators' motion, our scheme takes into consideration the varying configuration of the robotic system, as opposed to [36], in order to build a plan that can safely drive the robotic system to the goal configuration. More specifically, we devise a high-level planner which is tasked with building a sequence of adjacent configuration space cells of the overall system (i.e., robots and object) that connect the system's initial and desired configurations, each of which defines an allowable set of configurations for the object, as well as explicit intervals for each manipulator's states.…”

Decentralized Impedance Control for Cooperative Manipulation of Multiple Underwater Vehicle Manipulator Systems under Lean Communication

“…where the constant λ dictates the exponential convergence rate, ρ ij,∞ , i ∈ N denotes the ultimate bound and ρ ij,0 is chosen to satisfy ρ ij,0 > |e ij (0)|, i ∈ N . Hence, following [28], the estimation law is designed as follows:…”

Decentralized Navigation in 3D Space of a Robotic Swarm with Heterogeneous Abilities

“…Robotic swarms are used in such tasks as exploration [3], transportation [4], and surveillance [5]. They have a basic task in common: "moving to the destination while maintaining the swarm structure," and to realize this task by decentralized control, each agent needs to get information about the surroundings by sensing or communication and to determine their action based on it.…”