A sliding-mode controller for dual-user teleoperation with unknown constant time delays

Abstract

SUMMARYIn this paper, a control methodology is proposed for dual-user teleoperation system in the presence of unknown constant communication time delay. To satisfy dual-user system-desired objectives, three impedance characteristics are defined as the desired closed-loop system. In order to satisfy the desired impedance characteristics, a sliding-mode-based impedance controller is applied. The proposed controller affords unknown communication delay, an issue that is disregarded in the previous studies performed on dual-user systems. The nonlinear gain of the controller is achieved independent of time delay caused by communication channels. Therefore, the necessity of measurement or estimation of the time delay is relaxed. In addition, the stability analysis is presented for the closed-loop system using the passivity theory. The validity of the proposed controller scheme is demonstrated via experimental results performed on a dual-user system in the presence of unknown communication delay. In addition, due to lack of availability of forces corresponding to the operators’ hand that are required in the proposed controller, a Kalman Filter-based Force Observer (KFFO) is proposed.

Design of a Single-Master/Multi-Slave Nonlinear Teleoperation System through State Convergence with Time Varying Delays

“…We further assume that all the gamma constants are unity. The inequalities in (17), (18) are then solved which leads to the selection of decisive matrices as (20,10) K diag  and 1 (60,30)…”

Review of Advanced Medical Telerobots

“…A simple case is through a switching mechanism at the follower position controller so that the two surgeons can take turns to conduct the surgery when the other surgeon would go to an observation mode. This has been realized using the dual-user da Vinci surgical system when an expert surgeon conducts a task and then observe the conduction of the same task by the novice trainee [218,[269][270][271][272][273][274]. Instead of switching, fusion scenarios have been conducted when the motions of the two surgeons are fused through a mixing matrix to control the follower robot.…”

“…It should also be noted that such topology may suffer from a nonhomogeneous distribution of delay between different operators and between them and the follower robot, which calls for a specialized stabilization framework. One of the major challenges with the distributed delay is the complexity of the stabilization architecture [4,218,272,273]. Improving the performance, stability, and functionality of ML/SF topology is ongoing research, and several advanced topics have been investigated during the last decade.…”

“…This configuration refers to structures that have two leader stations for the cooperation of two operators on one follower console. This collaboration helps improve the task execution in comparison with the same task done individually [273]. The concept of haptic-enabled negotiation between two operators can be made feasible using this framework to control the follower console collaboratively through haptic communication [305].…”

“…More details on this can be found in Section 3.2 where we compare various autonomy levels. The wide literature related to DUST architectures can be categorized into two main branches of research: (1) control [150,207,[269][270][271][272][273][274]277,[306][307][308][309], and (2) Functionality [4,247,253,254,[258][259][260][261][262][263][264][265][266][267].…”