Analysis and Design of Time Delayed Control Systems with Communication Disturbance Observer

Abstract

This paper presents stability analysis and a novel design method of time delayed control systems. The time delayed control systems are constructed based on a time delay compensation method using the concept of network disturbance and communication disturbance observer. At first, the effect of time delay in control systems is described briefly and the effectiveness of the time delay compensation method is presented. Then analysis about the effects of parameters in control systems on stability of the time delayed control systems is analyzed. The main part of this paper is proposal of a novel design method of time delayed control systems according to the analytical results. Simulation results verify the validity of analytical results and proposed design method. The results also demonstrate the effectiveness of the time delay compensation method using the concept of network disturbance and communication disturbance observer

Model following control with discrete time SMC for time-delayed bilateral control systems

“…3 below. Further information about CDOB can be found in [8] and [9], whereas a stability analysis is given in [12].…”

“…Regarding the time delayed bilateral control, recently proposed Communication Disturbance Observer (CDOB) seems to bring a conclusion to stability problem originated from a variable delay of any magnitude [8], [9]. Disregard ing the model of the time delay, this method approaches the problem by lumping all undesired effects of time delay to a concept called network disturbance.…”

“…In [11] and [12], it is also shown that with the addition of PD convergence terms with equal gains to both observer and slave plant, position tracking of CDOB structure can be assured even though the initial positions and velocities of master and slave systems are different. However, the CDOB based structures developed in [8], [9]' [11] and [12] assume that there is perfect disturbance cancelation on the slave plant, which is a weak assumption in general. When there are rapid changes in the external forces, such as rapid contact with environment, position tracking of slave system deteriorates basically due to the limitations of DOB used in the slave plant.…”

Fieldbus based distributed servo control using LonWorks/IP gateway/web servers

“…Related to the time delay problem a comprehensive review of the time delay on NCS systems was done, and the advances and the open problems of the time delayed systems were also investigated in [24]. In order to resolve the stability problem of the NCS there have been stability analyses [25][26][27][28][29] and remote stabilization of the NCS has also been tried [30][31][32][33][34][35][36][37][38][39]. Stabilization of the NCS that has unknown time delay using the LMI (Linear Matrix Inequality) technique was suggested in [32].…”

“…Sufficient condition for the stability of Takagi-Sugeno fuzzy models equivalent to nonlinear systems with time delays was investigated, and the design of the shared control of the plural nonlinear systems within one controller was suggested in [33]. In [34][35][36] the communication disturbance observer was used to compensate for the time delay. In [37,38] the difference between the communication disturbance observer and Smith predictor was explained and the stability analysis and design procedure were suggested.…”