scholarly journals Adaptive Control of Teleoperation Systems With Linearly and Nonlinearly Parameterized Dynamic Uncertainties

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Xia Liu ◽  
Mahdi Tavakoli
Keyword(s):  
Adaptive Control ◽  
Function Analysis ◽  
Tracking Errors ◽  
Adaptive Controllers ◽  
Control Framework ◽  
Control Scheme ◽  
Force Tracking ◽  
Nonlinearly Parameterized ◽  
Teleoperation Systems ◽  
Dynamic Uncertainties

Existing work concerning adaptive control of uncertain teleoperation systems only deals with linearly parameterized (LP) dynamic uncertainties. Typical teleoperation system dynamics, however, also posses terms with nonlinearly parameterized (NLP) structures. An example of such terms is friction, which is ubiquitous in the joints of the master and slave robots of practical teleoperation systems. Uncertainties in the NLP dynamic terms may lead to significant position and force tracking errors if not compensated for in the control scheme. In this paper, adaptive controllers are designed for the master and slave robots with both LP and NLP dynamic uncertainties. Next, these controllers are incorporated into the 4-channel bilateral teleoperation control framework to achieve transparency. Then, transparency of the overall teleoperation is studied via a Lyapunov function analysis. Simulation studies demonstrate the effectiveness of the proposed adaptive scheme when exact knowledge of the LP and NLP dynamics is unavailable.

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.

scholarly journals Robust Fractional Adaptive Control Based on the Strictly Positive Realness Condition

2009 ◽  
Vol 19 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Samir Ladaci ◽  
Abdelfatah Charef ◽  
Jean Loiseau
Keyword(s):  
Adaptive Control ◽  
Fractional Order ◽  
Robust Adaptive Control ◽  
Adaptive Controllers ◽  
Actuator Dynamics ◽  
Control Scheme ◽  
Positive Realness ◽  
Robust Adaptive ◽  
Model Reference Adaptive ◽  
Strictly Positive Realness

Robust Fractional Adaptive Control Based on the Strictly Positive Realness ConditionThis paper presents a new approach to robust adaptive control, using fractional order systems as parallel feedforward in the adaptation loop. The problem is that adaptive control systems may diverge when confronted with finite sensor and actuator dynamics, or with parasitic disturbances. One of the classical robust adaptive control solutions to these problems makes use of parallel feedforward and simplified adaptive controllers based on the concept of positive realness. The proposed control scheme is based on the Almost Strictly Positive Realness (ASPR) property of the plant. We show that this condition implies also robust stability in the case of fractional order controllers. An application to Model Reference Adaptive Control (MRAC) with a fractional order adaptation rule is provided with an implementable algorithm. A simulation example of a SISO robust adaptive control system illustrates the advantages of the proposed method in the presence of disturbances and noise.

scholarly journals Composite adaptive control of a robotic joint for passive deployment applications

2002 ◽  
Vol 216 (3) ◽  
pp. 275-289
Author(s):  
A V C Reedman ◽  
K Bouazza-Marouf
Keyword(s):  
Adaptive Control ◽  
Control Strategies ◽  
Adaptive Controllers ◽  
Control Scheme ◽  
And Control ◽  
The Mathematical Model ◽  
Composite Adaptive Control ◽  
Single Worm ◽  
Adaptive Control Scheme ◽  
Computed Torque

A composite adaptive control scheme for the control of an actively constrained revolute joint with backlash cancellation is presented in this paper. The drive mechanism consists of two motor-driven worms coupled to a single worm wheel. The mathematical model and control strategies are reviewed. This is followed by the derivation of the composite adaptive controllers. Simulation and experimental results show that the composite adaptive control scheme gives an equivalent performance to a computed-torque algorithm without compromising the mechanism's ability to cancel backlash.

Modified Model-Free Adaptive Control Method Applied to Vibration Control of an Elastic Crane

2019 ◽  
Author(s):  
Hoang Anh Pham ◽  
Dirk Söffker
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
Structural Information ◽  
Control Strategies ◽  
Control Input ◽  
Tracking Errors ◽  
Adaptive Controllers ◽  
Control Approach ◽  
Model Free ◽  
Controlled Systems

Abstract Model-free adaptive control (MFAC) is a data-driven control approach receiving increased attention in the last years. Different model-free-based control strategies are proposed to design adaptive controllers when mathematical models of the controlled systems should not be used or are not available. Using only measurements (I/O data) from the system, a feedback controller is generated without the need of any structural information about the controlled plant. In this contribution an improved MFAC is discussed for control of unknown multivariable flexible systems. The main improvement in control input calculation is based on the consideration of output tracking errors and its variations. A new updated control input algorithm is developed. The novel idea is firstly applied for controlling vibrations of a MIMO ship-mounted crane. The control efficiency is verified via numerical simulations. The simulation results demonstrate that vibrations of the elastic boom and the payload of the crane can be reduced significantly and better control performance is obtained when using the proposed controller compared to standard model-free adaptive and PI controllers.

scholarly journals Inverse Jacobian Adaptive Tracking Control of Robot Manipulators with Kinematic, Dynamic, and Actuator Uncertainties

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Bing Zhou ◽  
Liang Yang ◽  
Chengdong Wang ◽  
Yong Chen ◽  
Kairui Chen
Keyword(s):  
Adaptive Control ◽  
Tracking Control ◽  
Robot Manipulators ◽  
Simulation Studies ◽  
Control Torque ◽  
Tracking Errors ◽  
Adaptive Tracking Control ◽  
Control Scheme ◽  
Adaptation Law ◽  
Control Methodology

In this paper, we mainly solve the adaptive control problem of robot manipulators with uncertain kinematics, dynamics, and actuators parameters, which has been a long-standing, yet unsolved problem in the robotics field, because of the technical difficulties in handling highly coupled effect between control torque and the mentioned uncertainties. To overcome the difficulties, we propose a new Lyapunov-based adaptive control methodology, which effectively fuses the inverse Jacobian technique and the actuator adaptation law, with which the chattering in tracking errors caused by actuator parameter perturbation is well suppressed. It is demonstrated that the asymptotic convergence of all closed-loop signals is guaranteed. Moreover, the effectiveness of our control scheme is illustrated through simulation studies.

Robust Adaptive Control Scheme for Teleoperation Systems With Delay and Uncertainties

2020 ◽  
Vol 50 (7) ◽  
pp. 3243-3253 ◽  
Author(s):  
Parham M. Kebria ◽  
Abbas Khosravi ◽  
Saeid Nahavandi ◽  
Peng Shi ◽  
Roohallah Alizadehsani
Keyword(s):  
Adaptive Control ◽  
Robust Adaptive Control ◽  
Control Scheme ◽  
Robust Adaptive ◽  
Teleoperation Systems ◽  
Adaptive Control Scheme

Cluster synchronization in fractional-order network with nondelay and delay coupling

2021 ◽  
pp. 2250006
Author(s):  
Yi Wang ◽  
Zhaoyan Wu
Keyword(s):  
Adaptive Control ◽  
Fractional Order ◽  
Cluster Synchronization ◽  
Sufficient Condition ◽  
Fractional Order Systems ◽  
Adaptive Controllers ◽  
Control Scheme ◽  
Control Schemes ◽  
The Stability ◽  
Adaptive Control Scheme

In this paper, cluster synchronization for fractional-order complex network with nondelay and delay coupling is investigated. Based on the stability theory of fractional-order systems and the properties of fractional derivative, both static and adaptive control schemes are adopted to design effective controllers. Sufficient condition for achieving cluster synchronization about static controllers is provided. From the condition, the needed feedback gains can be estimated by simple calculations. Further, adaptive control scheme is introduced to design unified controllers. Noticeably, in the adaptive controllers, the feedback gains need not be calculated in advance and can adjust themselves to the needed values according to updating laws. Finally, numerical simulations are given to demonstrate the correctness of the obtained results.

Synchronization of Unknown Uncertain Chaotic Systems Via Adaptive Control Method

2015 ◽  
Vol 10 (5) ◽  
Author(s):  
Mohammad Pourmahmood Aghababa ◽  
Bijan Hashtarkhani
Keyword(s):  
Adaptive Control ◽  
Chaotic Systems ◽  
Control Method ◽  
Lyapunov Stability Theory ◽  
Adaptive Controllers ◽  
Control Scheme ◽  
Uncertain Chaotic Systems ◽  
The Stability ◽  
Feedback Control Strategy ◽  
Adaptive Control Scheme

In this paper, an adaptive control scheme is offered to synchronize two different uncertain chaotic systems. It is assumed that the whole dynamics of both master and slave chaotic systems and their bounds are unknown and different. The error system stabilization is achieved in two cases: with input nonlinearities and without input nonlinearities. We design an adaptive control scheme based on the state boundedness property of the chaotic systems. The proposed method does not need any information about nonlinear/linear terms of the chaotic systems. It only uses an adaptive feedback control strategy. The stability of the proposed controllers is proved by using the Lyapunov stability theory. Finally, the designed adaptive controllers are applied to synchronize two different pairs of the chaotic systems (Lorenz–Chen and electromechanical device–electrostatic transducer).

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.

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