A novel structure for the optimal control of bilateral teleoperation systems with variable time delay

2011 ◽  
Vol 348 (7) ◽  
pp. 1537-1555 ◽  
Author(s):  
Soheil Ganjefar ◽  
Somayeh Najibi ◽  
HamidReza Momeni
Keyword(s):  
Optimal Control ◽  
Time Delay ◽  
Bilateral Teleoperation ◽  
Variable Time Delay ◽  
Variable Time ◽  
Novel Structure ◽  
Teleoperation Systems

Adaptive Control of a Macro/Micro Bilateral Teleoperation System Under Variable Time Delay

2010 ◽  
Author(s):  
A. Monemian Esfahani ◽  
S. M. Rezaei ◽  
M. Zareinejad ◽  
Mozafar Saadat
Keyword(s):  
Adaptive Control ◽  
Time Delay ◽  
Design Parameters ◽  
Piezo Actuator ◽  
Bilateral Teleoperation ◽  
Variable Time Delay ◽  
Variable Time ◽  
Robot Controller ◽  
Teleoperation System ◽  
Lyapunov Stability Criterion

In this paper a new stable adaptive control for a Macro-Micro bilateral teleoperation system is proposed. Our platform to implement the controllers consists of a servo DC motor (macro) as the master robot and a piezo-actuator (micro) as the slave robot. Piezo-actuator has some characteristics which disturb the transparency and stability of the teleoperation system. We add a nonlinear disturbance observer to the slave robot controller in order to observe and compensate the disturbances. It is recognized that the presence of time delay is one of the largest barriers in teleoperation systems. This problem is mainly due to the distance separating the master from the slave and also is due to lag effect of filters and motor drivers. Because the time delay is unknown and variable, it can make the system unstable. In this paper, all of the above controllers are discussed using variable time delay. The stability of the system under variable time delay is guaranteed by Lyapunov stability criterion and passivity based methods. Tracking of force/position is achieved by selecting the best design parameters. Performance of the proposed control is validated by experimental results.

scholarly journals On Adaptive Moving Average Algorithms for the Application of the Conservative Power Theory in Systems with Variable Frequency

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1201
Author(s):  
Daniel dos Santos Mota ◽  
Elisabetta Tedeschi
Keyword(s):  
Time Delay ◽  
Moving Average ◽  
Voltage Source ◽  
Moving Averages ◽  
Nonlinear Load ◽  
Power Theory ◽  
Variable Time Delay ◽  
Variable Time ◽  
Conservative Power Theory ◽  
Conservative Power

The Conservative Power Theory (CPT) emerged in recent decades as a theoretical framework for coping with harmonically distorted and unbalanced electric networks of ac power systems with a high participation of converter interfaced loads and generation. The CPT measurements are intrinsically linked to moving averages (MA) over one period of the grid. If the CPT is to be used in a low-inertia isolated-grid scenario, which is subjected to frequency variations, adaptive moving averages (AMA) are necessary. This paper reviews an efficient way of computing MAs and turns it into an adaptive one. It shows that an easily available variable time delay block, from MATLAB, causes steady-state errors in the measurements when the grid frequency varies. A new variable time delay block is, thus, proposed. Nonetheless, natural pulsations in the instantaneous power slip through MAs when the discrete moving average window does not fit perfectly the continuously varying period of the grid. A method consisting of weighing two MAs is reviewed and a new and effective hybrid AMA is proposed. The CPT transducers with the different choices of AMAs are compared via computer simulations of a single-phase voltage source feeding either a linear or a nonlinear load.

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