Distributed adaptive impedance control of networked Lagrangian systems with neighborhood interaction feedback

Abstract

In this study, a new distributed impedance control is proposed in networked Lagrangian systems to improve the compliant performance of each node in respective environment. Different from previous state consensus, this control objective focuses on the dynamic impedance cooperation of networked Lagrangian systems. The augmented impedance error is introduced in the distributed impedance control frame to evaluate the compliant performance of the designed controller. Based on this impedance control frame, the virtual interaction field is proposed to address some typical tasks such that avoid node collision and ensure high cooperation of neighborhood nodes. Then a distributed adaptive impedance controller together with the radial basis function neural network is employed to compensate the model uncertainties of networked Lagrangian systems and guarantee each note convergence to the prescribed dynamic impedance model, which is governed by the robot-environment interaction. Finally, the comparative simulations have verified the effectiveness of the proposed distributed impedance control method.

Extended State Observer-Based Sliding Mode Control Design of Two-DOF Lower Limb Exoskeleton

“…Based on (20) and the definition of the scaled estimation error ε, the state estimation errors qi = q i − qi (i = 1, 2, 3) converge to an arbitrarily small zero neighborhood by largely regulating the observer bandwidth ω 0 .…”

“…Furthermore, an adaptive backstepping control is constructed to improve the dynamic tracking performance of the human-robot training mode in the presence of the identification error [19]. Similarly, an adaptive impedance control is used in networked Lagrangian systems to simulate typical robot-environment interactions [20]. However, in the active mode, the joint trajectory demand is designed based on the human-exoskeleton interaction force/torque.…”

Impedance control for a Stewart‐structure‐based wheel‐legged robotic system in wheel motion

“…Different achievements in the field of impedance control have been proposed. [14][15][16][17] Based on the system impedance model calculated by the parameters of joints, the impedance control was achieved by sacrificing the position accuracy of the joint actuators, which was summarized as a joint-space impedance controller. 18 For the series structure, there exists a determined solution for the system impedance model.…”

Fixed‐time velocity‐free coordination control for human‐robot systems without any approximation function

“…The contributions of this paper are listed as follows 1. In contrast to existing strategies, [34][35][36] which require the measurement of the velocity information, a new approximation-free fixed-time velocity observer is designed to avoid using velocity sensor. The convergence performance of the velocity observer with system uncertainties is also discussed.…”

“…In contrast to Reference 33, the distributed control method is considered to reduce the requirement of computer performance for the controller designing in large scale network. The contributions of this paper are listed as follows In contrast to existing strategies, 34‐36 which require the measurement of the velocity information, a new approximation‐free fixed‐time velocity observer is designed to avoid using velocity sensor. The convergence performance of the velocity observer with system uncertainties is also discussed. Compared with the finite‐time control schemes, 31,37,38 the proposed control strategy achieves fixed‐time stability independent of the initial conditions.…”