Internal Mode Control Research Articles

Start-up current adaptive control for sensorless high-speed brushless DC motors based on inverse system method and internal mode controller

The start-up current control of the high-speed brushless DC (HS-BLDC) motor is a challenging research topic. To effectively control the start-up current of the sensorless HS-BLDC motor, an adaptive control method is proposed based on the adaptive neural network (ANN) inverse system and the two degrees of freedom (2-DOF) internal model controller (IMC). The HS-BLDC motor is identified by the online least squares support vector machine (OLS-SVM) algorithm to regulate the ANN inverse controller parameters in real time. A pseudo linear system is developed by introducing the constructed real-time inverse system into the original HS-BLDC motor system. Based on the characteristics of the pseudo linear system, an extra closed-loop feedback control strategy based on the 2-DOF IMC is proposed to improve the transient response performance and enhance the stability of the control system. The simulation and experimental results show that the proposed control method is effective and perfect start-up current tracking performance is achieved.

Nonlinear control of spacecraft formation flying with disturbance rejection and collision avoidance**Project supported by the National Natural Science Foundation of China (Grant No. 11404404).

A nonlinear controller for disturbances rejection and collision avoidance is proposed for spacecraft formation flying. The formation flying is described by a nonlinear model with the J2 perturbation and atmospheric drag. Based on the theory of the state-dependent Riccati equation (SDRE), a finite time nonlinear control law is developed for the nonlinear dynamics involved in formation flying. Then, a compensative internal mode (IM) control law is added to eliminate disturbances. These two control laws compose a finite time nonlinear tracking controller with disturbances rejection. Moreover, taking safety requirements into account, the repulsive control law is incorporated in the composite controller to perform collision avoidance manoeuvres. A numerical simulation is presented to demonstrate the effectiveness of the proposed method. Compared to the conventional control method, the proposed method provides better performance in the presence of the obstacles and external disturbances.

Governor design for hydropower plants by intelligent sliding mode variable structure control

This work proposes a neural-fuzzy sliding mode control scheme for a hydro-turbine speed governor system. Considering the assumption of elastic water hammer, a nonlinear mode of the hydro-turbine governor system is established. By linearizing this mode, a sliding mode controller is designed. The linearized mode is subject to uncertainties. The uncertainties are generated in the process of linearization. A radial basis function (RBF) neural network is introduced to compensate for the uncertainties. The update formulas for the neural networks are derived from the Lyapunov direct method. For the chattering phenomenon of the sliding mode control, a fuzzy logic inference system is adopted. In the sense of Lyapunov, the asymptotical stability of the system can be guaranteed. Compared with the internal mode control and the conventional PID control method, some numerical simulations verify the feasibility and robustness of the proposed scheme.

Tuning and Control Strategies for a Debutanizer Column

Various conventional control strategies was performed using Proportional Integral Derivative (PID) controller which have been applied for control of a debutanizer column. Tuning of PID control strategies studied are using Smith Predictor control, Internal Mode control, Cascade control, Feedback control and Feedforward-feedback control. The comparisons were conducted using MATLAB Simulation in SIMULINK. The comparison for each control strategy performance was conducted in terms of response towards set point changes, and to evaluate the Process Variable (PV) and Manipulated Variable (MV). The success of control strategies are determined by the stability of the process model obtained from each control strategies by evaluating the IAE value.

Enhanced PID Controllers Design Based on Modified Smith Predictor Control for Unstable Process with Time Delay

A two-degree-of-freedom control structure is proposed for a class of unstable processes with time delay based on modified Smith predictor control; the superior performance of disturbance rejection and good robust stability are gained for the system. The set-point tracking controller is designed using the direct synthesis method; the IMC-PID controller for disturbance rejection is designed based on the internal mode control design principle. The controller for set-point response and the controller for disturbance rejection can be adjusted and optimized independently. Meanwhile, the two controllers are designed in the form of PID, which is convenient for engineering application. Finally, simulation examples demonstrate the validity of the proposed control scheme.

Design and Implementation of a Rocket Launcher with Improved High Speed & Accuracy

Aiming at high speed and accuracy position control, this paper introduces design of an optimal internal mode control and sliding mode control for rocket launcher servo systems which have large varied moment of inertia, strong impact moment and load moment. Internal mode control designed by LQR theory can satisfy system requirement of the position loop in PMSM system. Sliding mode control can restrain effects that caused by model parameter perturbation and external disturbance and realize high performance position control. Simulation results show that the control method is simple and has better performances compared with PID controller.

A simple non‐minimum phase zero's predictor for open‐loop unstable processes

AbstractThis paper proposes a Smith‐type predictive compensator for open‐loop unstable processes that have non‐minimum phase zero. It has been well‐recognized that this type of predictor reported in the literature encounters internally unstable problem when applied to an open‐loop unstable process. To satisfy the internal stability, the proposed predictor utilizes the partial internal model principle. And, the controller is designed by internal mode control principal to have H2 optimal performance. Simulation examples are presented to illustrate that the proposed control scheme can give satisfactory performance and robustness. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.

Improvement of precision for pendulous integrating gyro accelerometer via adaptive internal model control

An adaptive internal mode control is proposed to eliminate effectively periodic disturbance with uncertain frequency caused by input error angle of PIGA (Pendulous Integrating Gyro Accelerometer). An adaptive algorithm with periodic disturbance frequency identification on line is applied and the internal model controller parameters are adjusted to eliminate disturbance. Then the convergence of this algorithm and the stability of the system are proved by the averaging method. Simulation results verify the proposed scheme can eliminate periodic disturbance and improve the test precision for PIGA effectively.

System identification using a genetic algorithm and its application to internal adaptive model control

AbstractThe requirement for the high‐quality control of complex and/or structure‐unknown plant is growing in the real‐world industrial machine. Indirect Adaptive Control (IAC), which identifies model and updates the controllers automatically, is one promising way expected to meet this requirement. The conventional IAC, however, is required to know the structure of the controlled plant, that is, the order of its transfer function, in advance. This paper presents a new IAC scheme which makes use of Genetic Algorithm (GA) in its identification part. In the proposed framework, the information on the order of the plant is not required since the genetic algorithm searches both the structure of the plant dynamics and its parameters autonomously. A two‐degree‐of‐freedom Internal Mode Control (IMC) is adopted as a basic control architecture since the indirect adaptation can be harmoniously embedded in it. The effectiveness of the proposed scheme is verified through numerical simulations and experiments applied to a velocity control of multimass systems. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 142(4): 45–55, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10103