Adaptive Robust Task-Space Control of Bilateral Teleoperation Systems with Time Delays

Author(s):  
Hanie Marufkhani ◽  
Negar Doustmohammadi ◽  
Iman Sharifi
Author(s):  
Hanlei Wang ◽  
Yongchun Xie

This paper investigates the task-space control framework for bilateral teleoperation with communication time delays. Teleoperation in task space R3 × SO(3) presents some distinctive features different from its joint-space counterpart, i.e., SO(3) is nonconvex and bears quite different structure from Euclidean space Rn. Through analyzing the energy flows at the two ports of the teleoperator, we rigorously define the task-space interaction passivity of the teleoperator. Based on this passivity framework, we propose delay-robust control schemes to achieve master–slave position/orientation synchronization. Singularity-free task-space interaction passivity of the closed-loop teleoperator is ensured by the proposed task-space control framework. Using Lyapunov–Krasovskii stability tool and Schwarz inequality, we analyze the performance of the proposed teleoperation control scheme. We also discuss the problems incurred by time-varying delays and the corresponding solutions. Simulation study on a master–slave teleoperator composed of two kinematically dissimilar six-degree of freedom (DOF) manipulators is performed to illustrate the performance of the proposed control approach.


Robotica ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 859-875 ◽  
Author(s):  
Da Sun ◽  
Fazel Naghdy ◽  
Haiping Du

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.


Robotica ◽  
2015 ◽  
Vol 35 (5) ◽  
pp. 1121-1136 ◽  
Author(s):  
Emre Uzunoğlu ◽  
Mehmet İsmet Can Dede

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.


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