scholarly journals A Study on the L2 Stability and Transparency of Three Channel Control Architectures in Bilateral Teleoperation under Time Delays

2021 ◽  
Author(s):  
Uğur TÜMERDEM
Keyword(s):  
Time Delays ◽  
Bilateral Teleoperation ◽  
Channel Control ◽  
L2 Stability

Transparent four-channel bilateral control architecture using modified wave variable controllers under time delays

Robotica ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 859-875 ◽  
Author(s):  
Da Sun ◽  
Fazel Naghdy ◽  
Haiping Du
Keyword(s):  
Time Delays ◽  
Large Time ◽  
Wave Transformation ◽  
Bilateral Teleoperation ◽  
Bilateral Control ◽  
Wave Variable ◽  
Guarantee System ◽  
Remote Environment ◽  
The Stability ◽  
Teleoperation Systems

SUMMARYStability and transparency are two critical indices of bilateral teleoperation systems. The wave variable method is a conservative approach to robustly guarantee system passivity under arbitrary constant time delays. However, the wave-variable-based reflection is an intrinsic problem in this method because it can significantly degrade system transparency and disorient the operator's perception of the remote environment. In order to enhance both the transparency and the stability of bilateral teleoperation systems in the presence of large time delays, a new four-channel (4-CH) architecture is proposed which applies two modified wave-transformation controllers to reduce wave-based reflections. Transparency and stability of the proposed system are analyzed and the improvement in these when using this method is measured experimentally. Results clearly demonstrate that the proposed method can produce high transparency and stability even in the presence of large time delays.

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.

Constant Visual and Haptic Time Delays in Simulated Bilateral Teleoperation: Quantifying the Human Operator Performance

2013 ◽  
Vol 22 (4) ◽  
pp. 271-290 ◽  
Author(s):  
Tariq Abuhamdia ◽  
Jacob Rosen
Keyword(s):  
Time Delay ◽  
Time Delays ◽  
Human Performance ◽  
Force Feedback ◽  
Bilateral Teleoperation ◽  
Haptic Information ◽  
Position Errors ◽  
Pick And Place ◽  
Place Task ◽  
Two Delays

Visual feedback and force feedback (haptics) are the two streams of information in a robotic bilateral teleoperation where the operator manipulates a robot in a remote location. Delivering the visual and the haptic information depends in part on the characteristics of the communication network and results in a nonsynchronized delay. The goal is to study the effect of constant nonsynchronized and synchronized time delay of visual and haptic information on the human teleoperation performance. The experimental setup included a virtual reality environment, which allows the operator to manipulate the virtual objects in a simulated remote environment through a haptic device that renders the force feedback. The visual and the haptic information were delayed independently in the range of 0–500 ms, creating 121 different scenarios of synchronized and nonsynchronized delays. Selecting specific parameters of the remote virtual environment guaranteed stable teleportation, given the time delays under study. The experimental tasks included tracing predefined geometrical shapes and a pick-and-place task, which simulates both structured and unstructured interactions under the influence of guiding forces. Eight subjects (n = 8) participated in the experiment performing three repetitions of three different teleoperation tasks with 121 combinations of visual and haptic time delays. The measured parameters that were used to assess the human performance were the task completion time and the position errors expressed as a function of the visual and the haptic time delay. Then, regression and ANOVA analyses were performed. The results indicated that the human performance is a function of the sum of the two delays. As the sum of the two delays increases, the human performance degrades and is expressed with an increase in completion time and position errors. The performance degradation is more pronounced in the pick-and-place task compared to the tracing task. In scenarios where the visual and the haptics information were out of synchronization, the human performance was better than intentionally delaying one source of information in an attempt to synchronize and unify the two delays. The results of this study may be applied to any teleoperation tasks over a network with inherent time delays and more specifically to telesurgery in which performance degradation due to time delay has a profound effect on the quality of the healthcare delivered, patient safety, and ultimately the outcomes of the surgical procedure itself.

Sign in / Sign up

Export Citation Format

Share Document