scholarly journals 2DOF IMC and Smith-Predictor-Based Control for Stabilised Unstable First Order Time Delayed Plants

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1064
Author(s):  
Mikulas Huba ◽  
Pavol Bistak ◽  
Damir Vrancic
Keyword(s):  
Internal Model ◽  
Closed Loop ◽  
Structural Instability ◽  
Internal Model Control ◽  
Smith Predictor ◽  
Unstable Systems ◽  
First Order ◽  
Long Run ◽  
Model Control ◽  
Two Degree Of Freedom

The article brings a brief revision of the two-degree-of-freedom (2-DoF) internal model control (IMC) and the 2-DoF Smith-Predictor-based (SP) control of unstable systems. It shows that the first important reason for distinguishing between these approaches is the limitations of the control action. However, it also reminds that, in addition to the seemingly lucrative dynamics of transients, the proposed approaches can conceal a tricky behavior with a structural instability, which may manifest itself only after a longer period of time. Instead, as one of possible reliable alternatives, two-step IMC and filtered Smith predictor (FSP) design are applied to unstable first-order time-delayed (UFOTD) systems. Firstly, the 2-DoF P controller yielding a double real dominant closed loop pole is applied. Only then the 2-DoF IMC or FSP controllers are designed, providing slightly slower, but more robust transients. These remain stable even in the long run, while also showing increased robustness.

scholarly journals Anisochronic Internal Model Control Design

10.14311/482 ◽  
2003 ◽  
Vol 43 (5) ◽  
Author(s):  
T. Vyhlídal ◽  
P. Zítek
Keyword(s):  
System Dynamics ◽  
Internal Model ◽  
Closed Loop ◽  
Control Design ◽  
Internal Model Control ◽  
Loop System ◽  
Closed Loop System ◽  
First Order ◽  
Dominant Pole ◽  
Model Control

The features of internal model control (IMC) design based on the first order anisochronic model are investigated in this paper. The structure of the anisochronic model is chosen in order to fit both the dominant pole and the dominant zero of the system dynamics being approximated. Thanks to its fairly plain structure, the model is suitable for use in IMC design. However, use of the anisochronic model in IMC design may result in so-called neutral dynamics of the closed loop. This phenomenon is studied in this paper via analysing the spectra of the closed loop system.

Design of a neural internal model control system for a robot

Robotica ◽  
2000 ◽  
Vol 18 (5) ◽  
pp. 505-512 ◽  
Author(s):  
D. T. Pham ◽  
Şahin Yildirim
Keyword(s):  
Internal Model ◽  
Neural Model ◽  
Internal Model Control ◽  
Bp Algorithm ◽  
Recurrent Networks ◽  
Neural Controller ◽  
Inverse Control ◽  
Control Scheme ◽  
Model Control ◽  
Two Degree Of Freedom

This paper describes the design of an Internal Model Control (IMC) system for a planar two-degree-of-freedom robot. IMC was investigated as an alternative to the basic inverse control scheme which is difficult to implement. The proposed IMC system consisted of a forward internal neural model of the robot, a neural controller and a conventional feedback controller, all of which were realised easily. Both the neural model and the neural controller were based on recurrent networks which were trained using the backpropagation (BP) algorithm. The paper presents the results obtained with two types of recurrent networks as well as a conventional PID system.

scholarly journals Stabilization of the Magnetic Levitation System

2021 ◽  
Vol 11 (21) ◽  
pp. 10369
Author(s):  
Štefan Chamraz ◽  
Mikuláš Huba ◽  
Katarína Žáková
Keyword(s):  
Closed Loop ◽  
Magnetic Levitation ◽  
Internal Model Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
First Order ◽  
Model Based ◽  
Model Control ◽  
Levitation System ◽  
Magnetic Levitation System

This paper contributes toward research on the control of the magnetic levitation plant, representing a typical nonlinear unstable system that can be controlled by various methods. This paper shows two various approaches to the solution of the controller design based on different closed loop requirements. Starting from a known unstable linear plant model—the first method is based on the two-step procedure. In the first step, the transfer function of the controlled system is modified to get a stable non-oscillatory system. In the next step, the required first-order dynamic is defined and a model-based PI controller is proposed. The closed loop time constant of this first-order model-based approach can then be used as a tuning parameter. The second set of methods is based on a simplified ultra-local linear approximation of the plant dynamics by the double-integrator plus dead-time (DIPDT) model. Similar to the first method, one possible solution is to stabilize the system by a PD controller combined with a low-pass filter. To eliminate the offset, the stabilized system is supplemented by a simple static feedforward, or by a controller proposed by means of an internal model control (IMC). Another possible approach is to apply for the DIPDT model directly a stabilizing PID controller. The considered solutions are compared to the magnetic levitation system, controlled via the MATLAB/Simulink environment. It is shown that, all three controllers, with integral action, yield much slower dynamics than the stabilizing PD control, which gives one motivation to look for alternative ways of steady-state error compensation, guaranteeing faster setpoint step responses.

Sign in / Sign up

Export Citation Format

Share Document