Networking improves robustness in flexible-joint multi-robot systems with only joint position measurements

Nuño, Emmanuel; Ortega, Roméo; Jayawardhana, Bayu; Basañez, Luis

doi:10.1016/j.ejcon.2013.09.005

Cited by 8 publications

(5 citation statements)

References 26 publications

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“…where N i is the set of agents transmitting information to the ith robot, w ij > 0 if j 2 N i and w ij D 0 otherwise. Similar to passivity-based (energy-shaping) synchronization [4,[56][57][58] and in order to ensure that the interconnection forces are generated by the gradient of a potential function, the following assumption is used in this paper: A1. The followers interconnection graph is undirected and connected.…”

Section: Modeling the Interconnectionmentioning

confidence: 99%

Task space consensus in networks of heterogeneous and uncertain robotic systems with variable time‐delays

Nuño

Aldana

Basañez

2016

Adaptive Control & Signal

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This work deals with the leader-follower and the leaderless consensus problems in networks of multiple robot manipulators. The robots are non-identical, kinematically different (heterogeneous), and their physical parameters are uncertain. The main contribution of this work is a novel controller that solves the two consensus problems, in the task space, with the following features: it estimates the kinematic and the dynamic physical parameters; it is robust to interconnecting variable-time delays; it employs the singularity-free unit-quaternions to represent the orientation; and, using energy-like functions, the controller synthesis follows a constructive procedure. Simulations using a network with four heterogeneous manipulators illustrate the performance of the proposed controller.Peer ReviewedPostprint (author's final draft

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Section: Modeling the Interconnectionmentioning

confidence: 99%

Task space consensus in networks of heterogeneous and uncertain robotic systems with variable time‐delays

Nuño

Aldana

Basañez

2016

Adaptive Control & Signal

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“…Similar to passivity-based (energy-shaping) synchronization [46][47][48] and in order to ensure that the interconnection forces are generated by the gradient of a potential function, the following assumption is used in this paper: A1. The interconnection graph is undirected and connected.…”

Section: Modeling the Interconnectionmentioning

confidence: 99%

Pose consensus in networks of heterogeneous robots with variable time delays

Aldana

Romero

Nuño

et al. 2014

Int. J. Robust. Nonlinear Control

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This paper proposes a novel pose (position and orientation) consensus controller for networks of heterogeneous robots modeled in the operational space. The proposed controller is a distributed proportional plus damping scheme that, with a slight modification, solves both the leader-follower and leaderless consensus problems. A singularity-free representation, unit quaternion, is used to describe the robots orientation, and the network is represented by an undirected and connected interconnection graph. Furthermore, it is shown that the controller is robust to interconnection variable time delays. Experiments with a network of two 6-degrees-of-freedom robots are presented to illustrate the performance of the proposed scheme. Copyright have to reach a certain agreement pose (consensus point). These problems have been widely studied for first-order and second-order linear time-invariant systems in the generalized coordinates space, that is, the case of linearized manipulators in the joint space. Some of the proposed approaches can be found in [10] where a hybrid consensus control protocol is reported; in [9], which deals with uncertain topologies with interconnection delays; in [20], which proposes consensus protocols for heterogeneous multi-agent systems; in [21], which presents a partial state feedback consensus controller; in [22], which reports a leader velocity estimator using the neighbors velocities; and in [12], which studies the consensus of identical linear systems. For a comprehensive study and further reference along this line, the reader may refer to [23] and [24]. Solutions for different nonlinear systems, in the joint space, are reported in [8,[25][26][27][28][29][30], for Euler-Lagrange (EL) systems, and in [31][32][33], for a more general class of nonlinear passive systems. The works [25] and [26] present a solution to the leader-follower case, provided that the leader position is available to all the followers. In [27] and [34], a solution to the leaderless case using simple proportional plus damping (PCd) controllers is reported. The work [28] proposes a sliding-based scheme for the leader-follower case assuming that the leader position and velocity are available only to a certain set of followers. In [29], a proportional controller and a velocity estimator are proposed to solve the leaderless consensus problem. The remarkable work [30] analyzes the concurrent synchronization of multiple EL systems in the joint space provided that the leader trajectory is available to all the followers, that the time delays are identical and constant, that the complete exact dynamics are known, and that the EL systems are identical. The use of adaptive controllers in [30] is restricted to only the leader-follower consensus problem and for the undelayed case.There are several interesting papers of cooperative control of multi-robot systems in the operational space, but most of them only address the orientation part. Among these are the following: [5], where an adaptive controller is proposed to solve the leader-fol...

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“…In fact, there is no absolute rigid connection between each manipulator joint of the robot and the driving motor at the base joint, due to the existence of the reducer, there is a certain flexibility between them. The advantage of the mechanical arm with this flexible joint is that it can absorb the impact force generated by external accidental collision and reduce the damage to the mechanical arm [6], but the disadvantage is that the damping delay in the movement process will cause the movement angle of the mechanical arm to no longer be consistent with the movement angle of the driving motor rotor, resulting in error, Its error accumulation will have an impact on the high-precision operation of space robot. Moreover, the joint flexibility of the manipulator will cause vibration in the process of motion at high speed [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Adaptive neural network vibration suppression control of flexible joints space manipulator based on H∞ theory

You¹,

Zhang²,

Shen³

et al. 2023

J. vibroeng.

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Considering the control problems caused by uncertainties such as inaccurate modeling, external disturbance and joint flexibility, a neural network control method based on H∞ is proposed. By establishing the dynamic model of the free-floating space robot with flexible joints, according to its dynamic characteristics, it is split into a slow subsystem model representing the rigid characteristics and a fast subsystem model representing the flexible characteristics. Based on the H∞ robust control theory, a robust controller based on neural network is designed to realize the decoupling control of the rigid dynamic model, The designed weight adaptive learning rate can ensure the online and real-time adjustment of parameters. Based on Lyapunov theory, it is proved that the designed controller can ensure that the L2 gain of the system is less than the given index. A feedback controller based on velocity differential is designed to compensate the angle error caused by joint flexibility. The experimental simulation results verify that the proposed control method is effective and has good engineering application value.

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Networking improves robustness in flexible-joint multi-robot systems with only joint position measurements

Cited by 8 publications

References 26 publications

Task space consensus in networks of heterogeneous and uncertain robotic systems with variable time‐delays

Task space consensus in networks of heterogeneous and uncertain robotic systems with variable time‐delays

Pose consensus in networks of heterogeneous robots with variable time delays

Adaptive neural network vibration suppression control of flexible joints space manipulator based on H∞ theory

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