An Analysis of Sampling Effect on the Absolute Stability of Discrete-time Bilateral Teleoperation Systems

TL;DR

This paper investigates how sampling time affects the absolute stability of discrete-time bilateral teleoperation systems, proposing a new stability condition based on sampling bounds and validating it through simulations and experiments.

Contribution

It introduces a method to calculate a lower bound on sampling period for stability and highlights the impact of sampling on system transparency and damping.

Findings

Derived a lower bound on sampling period for stability

Demonstrated the importance of sampling time on transparency and damping

Validated the stability conditions through simulations and experiments

Abstract

Absolute stability of discrete-time teleoperation systems can be jeopardized by choosing inappropriate sampling time architecture. A modified structure is presented for the bilateral teleoperation system including continuous-time slave robot, master robot, human operator, and the environment with sampled-data PD-like + dissipation controllers which make the system absolute stable in the presence of the time delay and sampling rates in the communication network. The output position and force signals are quantized with uniform sampling periods. Input-delay approach is used in this paper to convert the sampled-data system to a continuous-time counterpart. The main contribution of this paper is calculating a lower bound on the maximum sampling period as a stability condition. Also, the presented method imposes upper bounds on the damping of robots and notifies the sampling time importance on the transparency and stability of the system. Both simulation and experimental results are performed to show the validity of the proposed conditions and verify the effectiveness of the sampling scheme.