Switched-Delay Smith Predictor for the Control of Plants with Response-Delay Asymmetry

Abstract

The modification of a Smith predictor for the control of plants with response-delay asymmetry has been proposed. It was developed for application in frequency converters for the control of the speed of the AC induction motor drives of pumps used in water- and liquefied-petroleum-gas-supply systems. Such plants are characterized by long response delays, and often these delays are asymmetric, i.e., the response delay to the rising and falling plant-control signal is different. A distinctive feature of the proposed modification is that the value of the response delay in the model of the plant used for the realization of the Smith predictor is switched. The operation of the proposed switched-delay Smith predictor, which was used with the proportional-integral controller, was analyzed using a simulation and experimentally in a real water-supply system. The obtained results prove an advantage of the suggested solution.

A Combined Controller for Closed-Loop Control Systems Affected by Electromagnetic Interference

“…The work of the closed-loop control system based on the proposed combined PID/PI/I controller ( Figure 2 ) was analysed with the plants, the dynamics of which are described by the first-order plus dead-time (FOPDT) transfer function. Such a model of the plant was chosen because it describes the dynamics of many real industrial processes [ 32 , 33 , 34 , 35 , 36 , 37 ]. The response delay (dead-time) values were chosen based on the literature [ 32 , 33 , 34 , 35 , 36 , 37 ], as well as from the practice of application of control systems.…”

“…Such a model of the plant was chosen because it describes the dynamics of many real industrial processes [ 32 , 33 , 34 , 35 , 36 , 37 ]. The response delay (dead-time) values were chosen based on the literature [ 32 , 33 , 34 , 35 , 36 , 37 ], as well as from the practice of application of control systems. For example, the water supply systems for which this controller was developed had such response delay values, and their dynamics corresponded to the FOPDT transfer function.…”

“…Such a model of the plant was chosen because it describes the dynamics of many real industrial processes [32][33][34][35][36][37]. The response delay (dead-time) values were chosen based on the literature [32][33][34][35][36][37], as well The controller modes are switched by switches SW1-SW3 (Figure 2). The position of the switches is determined by the value of the control error e(t).…”

Enhanced Tracking in Legged Robots through Model Reduction and Hybrid Control Techniques: Addressing Disturbances, Delays, and Saturation

“…It allows for flexible adaptation to system variations and faults, improving control effectiveness (as shown in tracking issues of the joint angles and contact forces under disturbances using the previously designed LADRC-SMC. There are various approaches to address this issue, and we choose a simple and classical solution, SP [34,35], which forms a multi-loop control strategy (see Figure 4). This strategy decomposes the single-leg control system of a robot into multiple independent control loops, each of which is responsible for controlling specific variables or subsystems within the system.…”

Design and Optimization of Precision Fertilization Control System Based on Hybrid Optimized Fractional-Order PID Algorithm

“…In order to improve the stability of the control system, we utilize the Smith predictor for controller structure optimization. The Smith predictor involves estimating the controlled process's dynamic model in advance and introducing a compensator in parallel with the controlled object to compensate for the pure lag time of the controlled object [27]. This compensates for the controlled quantity lagged by τ time and feeds it back to the input of the controller in advance, enabling the controller to take action ahead of time.…”