Distributed cooperative object attitude manipulation

Abstract

This paper proposes a local information based control law in order to solve the planar manipulation problem of rotating a grasped rigid object to a desired orientation using multiple mobile manipulators. We adopt a multi-agent systems theory approach and assume that: (i) the manipulators (agents) are capable of sensing the relative position to their neighbors at discrete time instances, (ii) neighboring agents may exchange information at discrete time instances, and (iii) the communication topology is connected. Control of the manipulators is carried out at a kinematic level in continuous time and utilizes inverse kinematics. The mobile platforms are assigned trajectory tracking tasks that adjust the positions of the manipulator bases in order to avoid singular arm configurations. Our main result concerns the stability of the proposed control law.

Adaptive force/velocity control for multi-robot cooperative manipulation under uncertain kinematic parameters

“…Note that in order to perform a proper rotation, the computation ofv d ω incorporates an estimate of the end effector distanced ∈ R + . We further fix the center of rotation in the origin of the object frame which, for our particular choice of the object frame to lie in the geometrical center of the end effectors, results in minimal required kinetic end effector energy [9]. The signs for the terms involvingv Note further that the computation of the desired end effector velocities in (15) and (16) does not rely on the object frame {o} but on the local estimatesĉ i of this frame.…”

A high level decentralized tracking algorithm for three manipulators subject to motion constraints

“…The interesting aspect of our approach is that the object is modelled as a multi-agent formation subject to hard constraints on the distances between the agents, similarly to the approaches taken by the recent works [3], [4].…”

Exact solutions to the closed loop kinematics of an almost globally stabilizing feedback law on SO(3)

“…[1], we use rotation matrices directly and obtain an input signal with a norm that goes to zero as the control error is maximized. Our approach is however motivated by previous research on cooperative robotics in unstructured environments [5], [6] were a slow convergence rate may be preferable because of safety reasons and because of the inverse kinematics based approach that is used. Unlike [1], [2], [8], [9], [10], [11], [12] we use a purely kinematic model.…”

“…quadrotors [1], inverted 3-D pendulums [2], and robotic manipulators [3], [4], [5], [6]. The problem is inherently difficult due to the global topology of the underlying state space, the special orthogonal group SO (3).…”