High-Fidelity Bilateral Teleoperation Systems and the Effect of Multimodal Haptics

Abstract

In master-slave teleoperation applications that deal with a delicate and sensitive environment, it is important to provide haptic feedback of slave/environment interactions to the user's hand as it improves task performance and teleoperation transparency (fidelity), which is the extent of telepresence of the remote environment available to the user through the master-slave system. For haptic teleoperation, in addition to a haptics-capable master interface, often one or more force sensors are also used, which warrant new bilateral control architectures while increasing the cost and the complexity of the teleoperation system. In this paper, we investigate the added benefits of using force sensors that measure hand/master and slave/environment interactions and of utilizing local feedback loops on the teleoperation transparency. We compare the two-channel and the four-channel bilateral control systems in terms of stability and transparency, and study the stability and performance robustness of the four-channel method against nonidealities that arise during bilateral control implementation, which include master-slave communication latency and changes in the environment dynamics. The next issue addressed in the paper deals with the case where the master interface is not haptics capable, but the slave is equipped with a force sensor. In the context of robotics-assisted soft-tissue surgical applications, we explore through human factors experiments whether slave/environment force measurements can be of any help with regard to improving task performance. The last problem we study is whether slave/environment force information, with and without haptic capability in the master interface, can help improve outcomes under degraded visual conditions.

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

“…These control architectures are usually classified as position error based (PEB), direct force reflection (DFR), shared compliance control (SCC), and 4-channel (4CH) control methods [27]. Among them, the 4-channel architecture is the most general case and one that can achieve perfect transparency.…”

Disturbance observer-based control of non-linear haptic teleoperation systems

“…In a fully transparent teleoperation system we have x s = x m and f h = f e . If the master and the slave can be modeled by LTI impedances 1 Z m (s) and Z s (s), the 4-channel teleoperation system of Figure 1, when no disturbance observer is incorporated into it, becomes fully transparent in the absence of disturbances and delays if the controllers are chosen as [5] 1 Causal dynamic operator which maps position/velocity to force.…”

“…The most successful control scheme in achieving a fully transparent teleoperation system is the 4-channel architecture [3], [4], [5]. In spite of its good performance, the 4-channel control scheme is mostly suitable for fixed linear models.…”

Inverse dynamics-based adaptive control of nonlinear bilateral teleoperation systems

“…In an ideally transparent teleoperation system, through appropriate control signals and , the master and the slave positions and forces will match regardless of the operator and environment dynamics, i.e., and [20]. Since, we have obtained the unified closed-loop dynamics (16), we can use a unified Lyapunov function to show the transparency of the overall system as in this section.…”