Position and force tracking in nonlinear teleoperation systems under varying delays

Robotica ◽  
2014 ◽  
Vol 33 (4) ◽  
pp. 1003-1016 ◽  
Author(s):  
Farzad Hashemzadeh ◽  
Mahdi Tavakoli
Keyword(s):  
Nonlinear Dynamics ◽  
Communication Channel ◽  
Degree Of Freedom ◽  
Tracking Performance ◽  
Time Varying ◽  
Communication Delays ◽  
Teleoperation System ◽  
Control Scheme ◽  
Force Tracking ◽  
Teleoperation Systems

SUMMARYIn this paper, a novel control scheme is proposed to guarantee position and force tracking in nonlinear teleoperation systems subject to varying communication delays. Stability and tracking performance of the teleoperation system are proved using a proposed Lyapunov–Krasovskii functional. To show its effectiveness, the teleoperation controller is simulated on a pair of planar 2-DOF (degree of freedom) robots and experimented on a pair of 3-DOF PHANToM Premium 1.5A robots connected via a communication channel with time-varying delays. Both the planar robots in simulations and the PHANToM robots in experiments possess nonlinear dynamics.

A novel multilateral teleoperation scheme with power-based time-domain passivity control

2016 ◽  
Vol 40 (11) ◽  
pp. 3252-3262 ◽  
Author(s):  
Zheng Chen ◽  
Ya-Jun Pan ◽  
Jason Gu ◽  
Shane Forbrigger
Keyword(s):  
Time Domain ◽  
Communication Channel ◽  
Communication Channels ◽  
Bilateral Teleoperation ◽  
Communication Structure ◽  
Remote Operation ◽  
Teleoperation System ◽  
Control Scheme ◽  
Weighting Coefficients ◽  
Teleoperation Systems

Multilateral teleoperation systems, which are extended from the traditional bilateral teleoperation, have become subject to increasing attention in current years, with increasing industrial requirements, such as the remote operation of larger objects and more complex tasks. In this paper, a general multilateral teleoperation control problem is discussed, in which n masters remotely control n slaves through delayed communication channels. A novel communication structure is proposed to satisfy the multiple master–slave communication requirement, in which weighting coefficients are chosen freely to perform the weighted effects of different masters or slaves. Power-based time-domain passivity control is subsequently developed for the complex multiple master–slave communication channel, to achieve the passivity of multilateral teleoperation systems under time delay. Experiments on a teleoperation system with two masters and two slaves are described; the results verify the effectiveness of the proposed control scheme.

scholarly journals Delayed Bilateral Teleoperation of Wheeled Robots including a Command Metric

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Franco Penizzotto ◽  
Sebastian García ◽  
Emanuel Slawiñski ◽  
Vicente Mut
Keyword(s):  
Mobile Robot ◽  
System Architecture ◽  
Communication Channel ◽  
Force Feedback ◽  
Time Varying ◽  
Bilateral Teleoperation ◽  
Wheeled Robots ◽  
Teleoperation System ◽  
Control Scheme ◽  
The Stability

This paper proposes a control scheme applied to the delayed bilateral teleoperation of wheeled robots with force feedback, considering the performance of the operator’s command execution. In addition, the stability of the system is analyzed taking into account the dynamic model of the master as well as the remote mobile robot under asymmetric and time-varying delays of the communication channel. Besides, the performance of the teleoperation system, where a human operator drives a 3D simulator of a wheeled dynamic robot, is evaluated. In addition, we present an experiment where a robot Pioneer is teleoperated, based on the system architecture proposed.

scholarly journals Passive Transparency Compensation for Bilateral Teleoperators with Communication Delays

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Erick J. Rodríguez-Seda
Keyword(s):  
Control Strategy ◽  
Wave Impedance ◽  
Time Varying ◽  
Communication Delays ◽  
Bilateral Control ◽  
Control Scheme ◽  
Force Tracking ◽  
Scenarios Simulation ◽  
Hard Contact ◽  
Contact Tasks

One of the main challenges in the realization of time-delayed bilateral teleoperators is the stable adaptation of transparency when the remote environmental dynamics are time-varying. In this paper, we propose a bilateral control strategy that passively adjusts the transparency of the system when the slave robot transitions between two different environments. The proposed controller exploits the effect that the wave impedance (a design parameter of the passivity-based scattering transformation) has on transparency without comprising closed-loop stability, regardless of time-varying communication delays. To properly adjust transparency, the control scheme smoothly switches the wave impedance parameter between a low value, ideal for free motion, and a sufficiently large value, suited for hard-contact tasks. We show that, by adopting this strategy, the transmitted impedance to the operator approximates more closely the environmental impedance value. Furthermore, we theoretically prove master-slave position coordination and force tracking under different scenarios. Simulation results illustrate the effectiveness of the proposed control strategy.

Iterative learning algorithm with a quadratic criterion for linear time-varying systems

2002 ◽  
Vol 216 (3) ◽  
pp. 309-316 ◽  
Author(s):  
S N Huang ◽  
K K Tan ◽  
T H Lee
Keyword(s):  
Learning Algorithm ◽  
Linear Time ◽  
Tracking Error ◽  
Iterative Learning ◽  
Tracking Performance ◽  
Time Varying ◽  
Control Scheme ◽  
Time Varying Systems ◽  
Simulation Results ◽  
Learning Law

A novel iterative learning controller for linear time-varying systems is developed. The learning law is derived on the basis of a quadratic criterion. This control scheme does not include package information. The advantage of the proposed learning law is that the convergence is guaranteed without the need for empirical choice of parameters. Furthermore, the tracking error on the final iteration will be a class K function of the bounds on the uncertainties. Finally, simulation results reveal that the proposed control has a good setpoint tracking performance.

Bilateral coordination control of flexible master–slave manipulators using a partial differential equation model

2020 ◽  
pp. 107754632094547
Author(s):  
Le Li ◽  
Hongjun Yang ◽  
Jinkun Liu
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Dynamic Model ◽  
Vibration Suppression ◽  
Equation Model ◽  
Partial Differential ◽  
Bilateral Coordination ◽  
Teleoperation System ◽  
Control Scheme ◽  
Teleoperation Systems

In this study, we evaluate the coordination tracking control problem of a flexible master–slave teleoperation system. The system under consideration is based on a dynamic model described by a set of partial differential equations. Existing research on bilateral controllers is based on teleoperation systems composed of rigid master robots and rigid or flexible slave robots. In this work, we consider teleoperation systems with flexible master and slave robots. We dynamically model flexible master–slave manipulators using partial differential equations. Based on the dynamic model, a bilateral coordination controller is developed to realize the coordination angle tracking and vibration suppression of flexible master–slave manipulators. The teleoperation system is proven to be asymptotically stable under the control scheme. Numerical simulation results illustrate that the proposed controller is effective.

Bilateral Adaptive Control of Nonlinear Teleoperation Systems With Uncertain Dynamics and Dead-Zone

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Xia Liu ◽  
Mahdi Tavakoli
Keyword(s):  
Adaptive Control ◽  
Function Analysis ◽  
Dead Zone ◽  
Adaptive Controller ◽  
Bilateral Control ◽  
Uncertain Dynamics ◽  
Teleoperation System ◽  
Control Scheme ◽  
Teleoperation Systems ◽  
Dynamic Uncertainties

Dead-zone is one of the most common hard nonlinearities ubiquitous in master–slave teleoperation systems, particularly in the slave robot joints. However, adaptive control techniques applied in teleoperation systems usually deal with dynamic uncertainty but ignore the presence of dead-zone. Dead-zone has the potential to remarkably deteriorate the transparency of a teleoperation system in the sense of position and force tracking performance or even destabilizing the system if not compensated for in the control scheme. In this paper, an adaptive bilateral control scheme is proposed for nonlinear teleoperation systems in the presence of both uncertain dynamics and dead-zone. An adaptive controller is designed for the master robot with dynamic uncertainties and the other is developed for the slave robot with both dynamic uncertainties and unknown dead-zone. The two controllers are incorporated into the four-channel bilateral teleoperation control framework to achieve transparency. The transparency and stability of the closed-loop teleoperation system is studied via a Lyapunov function analysis. Comparisons with the conventional adaptive control which merely deal with dynamic uncertainties in the simulations demonstrate the validity of the proposed approach.

Delay Compensation for Teleoperation Systems Based on Communication Disturbance Observers

2016 ◽  
Vol 20 (7) ◽  
pp. 1044-1050
Author(s):  
Wen-An Zhang ◽  
◽  
Junkai Jin ◽  
Xiang Qiu ◽  
Li Yu
Keyword(s):  
Control Problem ◽  
Disturbance Rejection ◽  
Disturbance Observer ◽  
Controller Design ◽  
Design Method ◽  
Smith Predictor ◽  
Time Varying ◽  
Communication Delays ◽  
Delay Compensation ◽  
Teleoperation Systems

This paper investigates the control problem for a class of teleoperation systems with communication delays. The network-induced delays are usually inevitable in teleoperation systems, and may be time varying and unpredictable. Since the conventional Smith predictor is only useful for fixed delays, a novel delay compensation and controller design method is proposed in this paper. The proposed method combines a disturbance rejection controller and a communication disturbance observer (CDOB). Simulations are provided to show the effectiveness and superiority of the proposed delay compensation and controller design method.

scholarly journals A New Method for Bilateral Teleoperation Passivity under Varying Time Delays

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Farzad Hashemzadeh ◽  
Iraj Hassanzadeh ◽  
Mahdi Tavakoli ◽  
Ghasem Alizadeh
Keyword(s):  
Time Delays ◽  
Communication Channel ◽  
Time Varying ◽  
Constant Delay ◽  
Time Varying Delay ◽  
Teleoperation System ◽  
Virtual Time ◽  
Varying Delay ◽  
Disturbance Estimator

A new framework is proposed to mitigate the adverse effect of time-varying time delays on the passivity of a teleoperation system. To this end, the communication channel with time-varying delays is modeled as a constant-delay channel along with additive output disturbances. Then, disturbance estimator blocks are added in each of the feedforward and feedback paths to estimate these disturbances and to compensate for them. In the disturbance estimator block, there is a need for a virtual time-varying delay block such that the overall communication channel can be seen as one with a constant delay. We also propose a method for determining this virtual delay. Two PHANToM haptic devices connected through a communication channel with time-varying delays are considered for a case study. Simulation and experimental results confirm the efficiency of the proposed method in terms of passivating the teleoperation system in the presence of time-varying delays.

scholarly journals Position/Force Tracking Impedance Control for Robotic Systems with Uncertainties Based on Adaptive Jacobian and Neural Network

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Jinzhu Peng ◽  
Zeqi Yang ◽  
Tianlei Ma
Keyword(s):  
Neural Network ◽  
Impedance Control ◽  
Tracking Error ◽  
Tracking Performance ◽  
Robotic Systems ◽  
Position Tracking ◽  
External Disturbances ◽  
Outer Loop ◽  
Control Scheme ◽  
Force Tracking

In this paper, an adaptive Jacobian and neural network based position/force tracking impedance control scheme is proposed for controlling robotic systems with uncertainties and external disturbances. To achieve precise force control performance indirectly by using the position tracking, the control scheme is divided into two parts: the outer-loop force impedance control and the inner-loop position tracking control. In the outer-loop, an improved impedance controller, which combines the traditional impedance relationship with the PID-like scheme, is designed to eliminate the force tracking error quickly and to reduce the force overshoot effectively. In this way, the satisfied force tracking performance can be achieved when the manipulator contacts with environment. In the inner-loop, an adaptive Jacobian method is proposed to estimate the velocities and interaction torques of the end-effector due to the system kinematical uncertainties, and the system dynamical uncertainties and the uncertain term of adaptive Jacobian are compensated by an adaptive radial basis function neural network (RBFNN). Then, a robust term is designed to compensate the external disturbances and the approximation errors of RBFNN. In this way, the command position trajectories generated from the outer-loop force impedance controller can be then tracked so that the contact force tracking performance can be achieved indirectly in the forced direction. Based on the Lyapunov stability theorem, it is proved that all the signals in closed-loop system are bounded and the position and velocity errors are asymptotic convergence to zero. Finally, the validity of the control scheme is shown by computer simulation on a two-link robotic manipulator.

Sign in / Sign up

Export Citation Format

Share Document