Design and implementation of a modified communication disturbance observer for teleoperation systems

Abstract

Abstract:In this paper, a novel structure for a communication disturbance observer in teleoperation systems is proposed to achieve robust stability. A time delay compensation method based on the concept of network disturbance and a communication disturbance observer (CDOB) has been proposed in past research. Unlike model-based approaches, it works without a time delay model. Therefore, it can be implemented in teleoperation systems with unknown and timevarying delay. However, it has been observed that the system model errors and external disturbances seriously affect the steady-state characteristics. Hence, in this paper, to achieve robustness against disturbance and model uncertainty, the structure of the conventional CDOB is modified and a new structure for the CDOB in teleoperation systems is proposed, which uses the slave's delayed torque instead of its delayed position for time delay compensation. The desired transient response characteristic is achieved by designing the controller parameters. The time delay in the communication channel has been simulated by PCs in past studies, but in this paper, by implementing the communication channel through the TCP/IP protocol in the experimental setup, the effectiveness of the proposed structure is studied in the presence of real time delay and compared with the Smith predictor, the conventional CDOB, and other structures of CDOBs.

A nonlinear disturbance observer scheme for discrete time control systems

“…Robust control of systems having time delays has been an important research problem for many years [1][2][3] and disturbance observers have constituted effective solutions to the problem. Disturbance observer based control (DOBC) has been very popular during the last two decades and many contributions to the field have been made.…”

“…In another study, the disturbance observation problem has been considered in the framework of neural network aided model predictive control in discrete time in [2], where the goal is to follow constant reference signals with zero steady state error. The disturbance observer problem for telerobotic systems is studied in [3], where the transmission delay is considered as a difficulty to be alleviated and a continuous time approach with Smith predictor is developed. The notion of continuous time DOBC was introduced for the first time by Prof. Ohnishi in [4].…”

A LADRC based fuzzy PID approach to contour error control of networked motion control system with time‐varying delays

“…In the field of networked control systems, there are many network-induced delay compensation methods [21][22][23][24][25][26], such as the adaptive Smith predictors, switching system methods, and so on, but most of the algorithms are complex and difficult to apply in practice. Recently, a novel method termed the communication disturbance observer (CDOB) was presented in [27]. The network-induced delay is modeled as a disturbance, and the real-time estimation compensation is carried out by the CDOB.…”

Compensation of time delay effect in vehicle yaw stability control systems by using communication disturbance observer

“…Yöntemin önemli özelliklerinden biri tam (kesin) zaman gecikmesi modeline ihtiyaç duymaması ve hatta zamanla değişen gecikme durumlarında da iyi sonuçlar vermesidir. Yöntem daha sonra tek ve iki serbestlik dereceli döner manipülatörlere [6], [7] ve iletişim ağı tabanlı yürüyüş şekli rehabilitasyon cihazlarına [8], kablosuz hareket kontrol sistemlerine [9], [10] ve TCP/IP protokolü yoluyla birbirine bağlı teleoperasyon sistemlerinin kontrolüne [11] uygulanmıştır.…”