Modified two-degree-of-freedom Smith predictive control for processes with time-delay

Abstract

This article proposes an improved two-degree-of-freedom Smith predictive control method for typical industrial control systems. Smith predictive control is a classic control strategy designed for systems with pure lag. As an extension of Smith predictive control, internal model control can solve the time-delay problem effectively and make the controller design simple. Based on the two control algorithms, an enhanced control method with modified control structure is developed in this paper. In the design scheme, the set-point tracking and the disturbance rejection characteristics are decoupled, such that the set-point tracking and disturbance rejection controllers can be designed independently to achieve better control performance. The obtained control strategy possesses simple and convenient parameter tuning procedures. The validity of the proposed scheme is verified through theoretical analysis and simulation comparison with other control methods, and the results indicate that the proposed strategy shows better performance on set-point tracking and disturbance rejection.

A novel whale optimization smith predictor based on feedforward compensation for controlling wave rotor refrigeration process

“…The controller parameter optimized by WOA Li et al, 22 the controller parameters are selected manually, while the WOA algorithm can simplify the setting process of the controller parameters due to its advantages of simple mechanism, few parameters and strong optimization ability. The flow chart of WOA algorithm to optimize the controller parameter is shown in Figure 9.…”

Modified power rate sliding mode control for robot manipulator based on particle swarm optimization

“…Where u dis is the discontinuous control that drives the system states to the sliding surface in the reaching mode by a constant gain, and u eq is the equivalent control that keeps the states on the sliding surface in the sliding mode [13], [32], Figure 2 illustrates the phase plane trajectory of the sliding mode control. Designing the control law comes from the Lyapunov's function as (10):…”

“…Operating the robot manipulators is a challenging task due to its nonlinear equations of motion which complicate the task of controlling the manipulator. Several types of controllers used to operate the robotic arm such as sliding mode control (SMC) [1], H-infinity control [2], Finite-time control [3], [4], active disturbance rejection control (ADRC) [5], time-delay control [6], high-order super-twisting sliding mode control [7], optimal control [8]- [9], and predictive control [10]. These control techniques vary from being sensitive to parameters change, hard to find their suitable operating parameters, requiring full knowledge of the model dynamics and having IAES Int J Rob & Autom ISSN: 2722-2586 Ì 169 complex control structure.…”

Dynamic systems with delays under the smith predictor methodology

“…The system is stable if all natural frequencies are in the left complex semiplane. Dead times or delays present in a system reduce the phase margin which implies that the system may become oscillatory and unstable [11][12][13][14][15][16].…”

“…The structure of the Smith predictor (SP) is given by the following internal model representation. Next, a deduction of the closed-loop transfer function for the Smith predictor is presented graphically and analytically (Figure 1 to Figure 4) and analytically (Equation(1) to Equation ( 8) ) [15]. It is then desired to obtain an equivalent controller for the system that contains the loop generated by the prediction…”