Neural Network-Based Control of Networked Trilateral Teleoperation With Geometrically Unknown Constraints

Abstract

Abstract-Most studies on bilateral teleoperation assume known system kinematics and only consider dynamical uncertainties. However, many practical applications involve tasks with both kinematics and dynamics uncertainties. In this paper, trilateral teleoperation systems with dual-master-single-slave framework are investigated, where a single robotic manipulator constrained by an unknown geometrical environment is controlled by dual masters. The network delay in the teleoperation system is modeled as Markov chain-based stochastic delay, then asymmetric stochastic time-varying delays, kinematics and dynamics uncertainties are all considered in the force-motion control design. First, a unified dynamical model is introduced by incorporating unknown environmental constraints. Then, by exact identification of constraint Jacobian matrix, adaptive neural network approximation method is employed, and the motion/force synchronization with time delays are achieved without persistency of excitation condition. The neural networks and parameter adaptive mechanism are combined to deal with the system uncertainties and unknown kinematics. It is shown that the system is D. Wang is with the Key Laboratory of Autonomous System and Network Control, Ministry of Education, South China University of Technology, Guangzhou, China, and also with the College of Automation Science and Engineering, South China University of Technology, Guangzhou,

Adaptive Control of Delayed Teleoperation Systems with Parameter Convergence

“…The slave is in free motion in this simulation. By applying the designed controller (6), (8), (9), (10), and (11) with = = 5 , = = 0.5, we obtain the simulation results as shown in Figures 2 and 3. It can be seen that, under the proposed controller, the presence of parametric uncertainties does not violate the stability of the bilateral teleoperation.…”

“…In order to solve this problem, a variety of control schemes have been proposed in the literature. The breakthrough work on bilateral teleoperation problem was achieved in [1], in which the concepts from network theory, passivity, and scattering theory were used to analyze the stability of the controlled teleoperation systems [2], and then the master-slave synchronization and stability analysis of teleoperation systems with various kinds of time delays, such as constant delays [1], time-varying delays [3][4][5][6][7][8], or stochastic delays [9][10][11], have been hot topics in the study of teleoperation systems.…”

Neural Network-Based Passivity Control of Teleoperation System Under Time-Varying Delays

“…As a result, the impedances-matching approach of the system in [11] fails to work at the transient state to the extent that the wave-reflections are restored causing large perturbations that adversely affect the position and torque tracking performances of the system in [11] as shown in Fig.7. By contrast, based on the designed wave variables in (20)- (23), the outgoing signals do not contain necessary signals and the wave reflections are eliminated. Therefore, the proposed system has better performance on the transient state and the position error directly returned to zero after removing the wall as shown in Fig.8.…”

“…In [18] NN is deployed for systems with time-varying delays, but the approach requires precise knowledge of the external force as well as the coefficients of mass and damper of the external force. [19] and [20] extend the application of NN to multilateral teleoperation. The major drawbacks of these studies are some of the assumptions underlying them.…”

Control of bilateral teleoperators with time delays using only position measurements

“…For an illustrative historical survey along this line, the reader may refer to the work of Hokayem and Spong and, for a passivity‐based control tutorial, to the work of Nuño et al Most of the teleoperators consider only one manipulator at the local and the remote sites. Recently, the work of Li et al has considered the case of multiple manipulators interacting with multiple operators and multiple remote manipulators collaborating in handling one object …”