Nonlinear Bilateral Adaptive Impedance Control With Applications in Telesurgery and Telerehabilitation

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Mojtaba Sharifi ◽  
Saeed Behzadipour ◽  
Hassan Salarieh
Keyword(s):  
Degrees Of Freedom ◽  
Impedance Control ◽  
Joint Space ◽  
Cartesian Coordinates ◽  
Teleoperation System ◽  
Force Tracking ◽  
Asymptotic Tracking ◽  
The Stability ◽  
Teleoperation Systems ◽  
Impedance Models

A bilateral nonlinear adaptive impedance controller is proposed for the control of multi-degrees-of-freedom (DOF) teleoperation systems. In this controller, instead of conventional position and/or force tracking, the impedance of the nonlinear teleoperation system is controlled. The controller provides asymptotic tracking of two impedance models in Cartesian coordinates for the master and slave robots. The proposed bilateral controller can be used in different medical applications, such as telesurgery and telerehabilitation, where the impedance of the robot in interaction with human subject is of great importance. The parameters of the two impedance models can be adjusted according to the application and corresponding objectives and requirements. The dynamic uncertainties are considered in the model of the master and slave robots. The stability and the tracking performance of the system are proved via a Lyapunov analysis. Moreover, the adaptation laws are proposed in the joint space for reducing the computational complexity, however, the controller and the stability proof are all presented in Cartesian coordinates. Using simulations on a 2DOF robot, the effectiveness of the proposed controller is investigated in telesurgery and telerehabilitation operations.

Robust Impedance Control of a Teleoperation System With Friction Compensation Under Time Delay

2009 ◽  
Author(s):  
A. Monemian Esfahani ◽  
S. M. Rezaei ◽  
M. Zareinejad
Keyword(s):  
Time Delay ◽  
Sliding Mode ◽  
Impedance Control ◽  
Control Input ◽  
Friction Forces ◽  
Teleoperation System ◽  
Force Tracking ◽  
Friction Observer ◽  
The Stability ◽  
Perturbation Estimation

Friction forces in the robot joints insert nonlinearity in the dynamic and make errors in tracking. In this paper a new impedance control for the master is proposed to achieve force tracking. In addition, an impedance control for slave combined with sliding mode, which is based on perturbation estimation, is anticipated to reach position tracking. Friction compensators typically include a friction observer that provides a cancellation term in order to be added to the control input. Estimating and compensating the friction and other uncertainties will change the nonlinear equation to a linear one. The stability of entire system under time delay is guaranteed by Llewellyn’s absolute stability criterion. Performance of the proposed controllers is investigated through experiments.

scholarly journals Energy-Optimized Consensus Formation Control for the Time-Delayed Bilateral Teleoperation System of UAVs

2018 ◽  
Vol 2018 ◽  
pp. 1-22 ◽  
Author(s):  
Hui-yu Sun ◽  
Guang-ming Song ◽  
Zhong Wei ◽  
Ying Zhang
Keyword(s):  
Energy Dissipation ◽  
Formation Control ◽  
Communication Complexity ◽  
Environmental Constraints ◽  
Bilateral Teleoperation ◽  
Consensus Formation ◽  
Human In The Loop ◽  
Teleoperation System ◽  
Force Tracking ◽  
The Stability

This paper proposes an energy-optimized consensus formation scheme for the time-delayed bilateral teleoperation system of multiple unmanned aerial vehicles (UAVs) in the obstructed environment. To deal with the asymmetric time-varying delays in aerial teleoperation, the local damping is independently distributed on both sides to enforce consensus formation and force tracking of the master haptic device and the slave UAVs. The stability of the time-delayed aerial teleoperation system is analyzed by the Lyapunov function. In addition, a flux-conserved force field is incorporated into the aerial teleoperation system to guarantee a collision-free consensus formation in the obstructed environment. Moreover, to reduce the communication complexity and energy dissipation of the formation, a top-down strategy of 3D optimal persistent graph is first proposed to optimize the formation topology. Under the optimized topology with environmental constraints, communication complexity and energy dissipation can be minimized while the rigid formation can be maintained and transformed persistently in the obstructed environment. Finally, the human-in-the-loop simulations are performed to validate the effectiveness of the proposed scheme.

scholarly journals Robust state dependent Riccati equation variable impedance control for robotic force-tracking tasks

2020 ◽  
Vol 4 (4) ◽  
pp. 507-519
Author(s):  
Loris Roveda ◽  
Dario Piga
Keyword(s):  
Riccati Equation ◽  
High Performance ◽  
Impedance Control ◽  
Industrial Robots ◽  
Intrinsic Variability ◽  
State Dependent ◽  
Force Tracking ◽  
Lqr Controller ◽  
Improved Performance ◽  
The Stability

AbstractIndustrial robots are increasingly used in highly flexible interaction tasks, where the intrinsic variability makes difficult to pre-program the manipulator for all the different scenarios. In such applications, interaction environments are commonly (partially) unknown to the robot, requiring the implemented controllers to take in charge for the stability of the interaction. While standard controllers are sensor-based, there is a growing need to make sensorless robots (i.e., most of the commercial robots are not equipped with force/torque sensors) able to sense the environment, properly reacting to the established interaction. This paper proposes a new methodology to sensorless force control manipulators. On the basis of sensorless Cartesian impedance control, an Extended Kalman Filter (EKF) is designed to estimate the interaction exchanged between the robot and the environment. Such an estimation is then used in order to close a robust high-performance force loop, designed exploiting a variable impedance control and a State Dependent Riccati Equation (SDRE) force controller. The described approach has been validated in simulations. A Franka EMIKA panda robot has been considered as a test platform. A probing task involving different materials (i.e., with different stiffness properties) has been considered to show the capabilities of the developed EKF (able to converge with limited errors) and controller (preserving stability and avoiding overshoots). The proposed controller has been compared with an LQR controller to show its improved performance.

scholarly journals Extending model-mediation method to multi-degree-of-freedom teleoperation systems experiencing time delays in communication

Robotica ◽  
2015 ◽  
Vol 35 (5) ◽  
pp. 1121-1136 ◽  
Author(s):  
Emre Uzunoğlu ◽  
Mehmet İsmet Can Dede
Keyword(s):  
Time Delays ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Test Results ◽  
Bilateral Teleoperation ◽  
Extended Version ◽  
Teleoperation System ◽  
Teleoperation Systems ◽  
Three Degrees Of Freedom

SUMMARYIn this study, a bilateral teleoperation control algorithm is developed in which the model-mediation method is integrated with an impedance controller. The model-mediation method is also extended to three-degrees-of-freedom teleoperation. The aim of this controller is to compensate for instability issues and excessive forcing applied to the slave environment stemming from time delays in communication. The proposed control method is experimentally tested with two haptic desktop devices. Test results indicate that stability and passivity of the bilateral teleoperation system is preserved under variable time delays in communication. It is also observed that safer interactions of the slave system with its environment can be achieved by utilizing an extended version of the model-mediation method with an impedance controller.

Transparency Improvement by External Force Estimation in a Time-Delayed Nonlinear Bilateral Teleoperation System

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
H. Amini ◽  
S. M. Rezaei ◽  
Ahmed A. D. Sarhan ◽  
J. Akbari ◽  
N. A. Mardi
Keyword(s):  
Control Algorithm ◽  
Force Measurement ◽  
Bilateral Teleoperation ◽  
Force Estimation ◽  
Teleoperation System ◽  
Control Scheme ◽  
Environmental Force ◽  
The Stability ◽  
External Forces ◽  
Teleoperation Systems

Teleoperation systems have been developed in order to manipulate objects in environments where the presence of humans is impossible, dangerous or less effective. One of the most attractive applications is micro telemanipulation with micropositioning actuators. Due to the sensitivity of this operation, task performance should be accurately considered. The presence of force signals in the control scheme could effectively improve transparency. However, the main restriction is force measurement in micromanipulation scales. A new modified strategy for estimating the external forces acting on the master and slave robots is the major contribution of this paper. The main advantage of this strategy is that the necessity for force sensors is eliminated, leading to lower cost and further applicability. A novel control algorithm with estimated force signals is proposed for a general nonlinear macro–micro bilateral teleoperation system with time delay. The stability condition in the macro–micro teleoperation system with the new control algorithm is verified by means of Lyapunov stability analysis. The designed control algorithm guarantees stability of the macro–micro teleoperation system in the presence of an estimated operator and environmental force. Experimental results confirm the efficiency of the novel control algorithm in position tracking and force reflection.

Bilateral Parallel Force/Position Teleoperation Control

1999 ◽  
Author(s):  
Keyvan Hashtrudi-Zaad ◽  
Septimiu E. Salcudean
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Position Tracking ◽  
Task Space ◽  
Closed Loop System ◽  
Teleoperation System ◽  
And Performance ◽  
The Stability ◽  
Teleoperation Systems ◽  
Decoupled Systems

Abstract The application of parallel force/position control to teleoperation systems is considered in this paper. Higher priority is given to position control at the master side and to force control at the slave side of the teleoperation system. The stability and performance of the proposed controller is investigated by analyzing the three decoupled systems obtained from projecting the closed-loop system dynamics onto the slave task-space orthogonal directions. Experimental results demonstrate the excellent force and position tracking performance provided by the new controller.

Nonlinear Disturbance Observer Based Impedance Control for a Teleoperation System Under Time Delay

2009 ◽  
Author(s):  
A. Monemian Esfahani ◽  
S. M. Rezaei ◽  
M. Zareinejad
Keyword(s):  
Time Delay ◽  
Disturbance Observer ◽  
Impedance Control ◽  
Fixed Time ◽  
Design Parameters ◽  
Control Input ◽  
Nonlinear Disturbance Observer ◽  
Teleoperation System ◽  
Nonlinear Disturbance ◽  
The Stability

In this paper a nonlinear disturbance observer (NDO) based impedance control is proposed for a teleoperation system. The unknown friction and uncertainties will be estimated by the observer and added to the control input for compensation. Although friction will improve the stability, it worsens the transparency of the system which is another major point in teleoperation systems. The stability of the system is guaranteed by Lyapunov stability criterion and selecting the best design parameters. Tracking of force/position is achieved by these parameters. Also a fixed time delay is added to the system because of delays in the cables and other sources, it is then compensated with the designed controller. Performance of the proposed control is validated by experimental results.

Stable Nonlinear Trilateral Impedance Control for Dual-User Haptic Teleoperation Systems With Communication Delays

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Mojtaba Sharifi ◽  
Hassan Salarieh ◽  
Saeed Behzadipour ◽  
Mahdi Tavakoli
Keyword(s):  
Absolute Stability ◽  
Impedance Control ◽  
Communication Delays ◽  
Haptic System ◽  
Impedance Model ◽  
Human Operators ◽  
Impedance Parameters ◽  
Teleoperation Systems ◽  
Dual User ◽  
Impedance Models

A new nonlinear adaptive impedance-based trilateral controller is proposed to ensure the absolute stability of multi-degrees-of-freedom (DOFs) dual-user haptic teleoperation systems subjected to communication delays. Using this strategy, reference impedance models are realized for the trilateral teleoperation system represented by a three-port network to facilitate cooperation of two human operators in order to perform a remote physical task. For this purpose, an impedance model defines the desired haptic interaction between the two human operators, while another impedance model specifies the desired behavior of the slave robot in terms of tracking the mater robots' trajectories during interaction with the remote environment. It is shown that different performance goals such as position synchronization and force reflection can be achieved via different adjustments to the impedance parameters. The sufficient conditions for the trilateral haptic system's absolute stability are investigated in terms of the impedance models' parameters. Accordingly, guidelines for modification of the impedance parameters are obtained to guarantee the absolute stability of the trilateral haptic system in the presence of communication time delays. A trilateral nonlinear version of the model reference adaptive impedance control (MRAIC) scheme is developed for implementing the proposed reference impedance models on the masters and the slave. The convergence of robots' trajectories to desired responses and the robustness against modeling uncertainties are ensured using the proposed controller as proven by the Lyapunov stability theorem. The proposed impedance-based control strategy is evaluated experimentally by employing a nonlinear multi-DOFs teleoperated trilateral haptic system with and without communication delays.

scholarly journals Stabilization of Teleoperation Systems with Communication Delays: An IMC Approach

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yuling Li
Keyword(s):  
Time Delays ◽  
Closed Loop ◽  
Internal Model Control ◽  
Bilateral Teleoperation ◽  
Closed Loop System ◽  
Teleoperation System ◽  
Model Control ◽  
The Stability ◽  
External Forces ◽  
Teleoperation Systems

The presence of time delays in communication introduces a limitation to the stability of bilateral teleoperation systems. This paper considers internal model control (IMC) design of linear teleoperation system with time delays, and the stability of the closed-loop system is analyzed. It is shown that the stability is guaranteed delay-independently. The passivity assumption for external forces is removed for the proposed design of teleoperation systems. The behavior of the resulting teleoperation system is illustrated by simulations.

scholarly journals Control of teleoperation systems in the presence of cyber attacks: A survey

2021 ◽  
Vol 10 (3) ◽  
pp. 235
Author(s):  
Mutaz M. Hamdan ◽  
Magdi S. Mahmoud
Keyword(s):  
Communication Network ◽  
Control Systems ◽  
Control Design ◽  
Main Idea ◽  
Cyber Attacks ◽  
Bilateral Teleoperation ◽  
Teleoperation System ◽  
Comprehensive Survey ◽  
The Stability ◽  
Teleoperation Systems

<p>The teleoperation system is often composed of a human operator, a local master manipulator, and a remote slave manipulator that are connected by a communication network. This paper proposes a survey on feedback control design for the bilateral teleoperation systems (BTSs) in nominal situations and in the presence of cyber-attacks. The main idea of the presented methods is to achieve the stability of a delayed bilateral teleoperation system in the presence of several kinds of cyber attacks. In this paper, a comprehensive survey on control systems for BTSs under cyber-attacks is discussed. Finally, we discuss the current and future problems in this field.</p>

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