Operator-based nonlinear feedback control design using robust right coprime factorization

In this note, robust stabilization and tracking performance of operator based nonlinear feedback control systems are studied by using robust right coprime factorization. Specifically, a new condition of robust right coprime factorization of nonlinear systems with unknown bounded perturbations is derived. Using the new condition, a broader class of nonlinear plants can be controlled robustly. When the spaces of the nonlinear plant output and the reference input are different, a space change filter is designed, and in this case this note considers tracking controller design using the exponential iteration theorem

Continuous-time anti-windup generalized predictive control of non-minimum phase processes with input constraints

This paper deals with a design problem of a continuous-time anti-windup generalized predictive control system using coprime factorization approach for non-minimum phase processes with input constraints. Based on the proposed design scheme, a condition for stability of the closed-loop system with input constraints and a straightforward method to improve the output response of the system with input constraints are given. Simulation results are presented to support the theoretical analysis.</p

Continuous-Time Anti-Windup Generalized Predictive Control of an MIMO Boiler System

This paper deals with a continuous-time anti-windup generalized control to a multivariable boiler experimental system. Water temperature and water level of the experimental system need to be controlled, but the heater and water flow of the experimental system are limited, namely, the experimental system is a multivariable system with control input constraints. For this system, a multivariable continuous-time anti-windup generalized predictive controller is designed. The effectiveness of the proposed design scheme is confirmed by experiment.</p

Tracking of perturbed nonlinear plants using robust right coprime factorization approach

This paper deals with a plant output tracking design problem of perturbed nonlinear plants by using a robust right coprime factorization approach. An interesting control system design scheme, which was given by G. Chen and Z. Han, uses robustness of the right coprime factorization for robust stability of the closed-loop system with perturbation. Unfortunately, robust right coprime factorization cannot easily improve tracking performance of the control system except for simple cases. In this paper, a nonlinear operator-based design method for nonlinear plant output to track a reference input is given. Examples are presented to support the theoretical analysis.</p

On-line actuator state monitoring of a MIMO bioprocess

In the actuator state monitoring of a time varying human multi-joint arm dynamics, typical issues are compounded by problems related to the uncertainty factor consisting of measurement noises and modeling error of the rigid body dynamics. In general, the uncertainty factor is under the case of non-Gaussian noises. In this paper, for improving the monitoring, a robust filter system based on a score function approach is modified. The score function is associated with U_D factorization algorithm. The selection of the shape parameter in the monitoring filter is discussed. Examples of the proposed method for an experiment-based human arm model show better accuracy and robustness compared with standard Kalman filter.</p

Continuous-time anti-windup generalized predictive control of uncertain processes with input constraints and time delays

In this paper, a design problem of a continuous-time anti-windup generalized predictive control (CAGPC) system using coprime factorization approach for uncertain processes with input constraints and time delays is considered. The uncertainty of the process is considered as an uncertain time delay. To reduce the effect of the input constraint and uncertain delay, controller for strong stability of the closed-loop system is designed. As a practical appeal, the effectiveness of the proposed design scheme is confirmed by a simulated application to an industrial process with input constraint and uncertain time delay.</p

Attitude control system design of a helicopter experimental system

In this paper, we consider the problem of attitude control of a helicopter experimental system. We design a nonlinear controller which combines nonlinear adaptive robust control and nonlinear feedback controls. Simulation and experimental results show the effectiveness of the proposed method.</p

On-line Identification of Electro-Conductivity in Electrolytic Solutions

An on-line method is proposed to identify electro-conductivity in electrolytic solutions. The method uses a model of a cell of electrolytic solutions in a micro reactor modeled by an electronic circuit. The circuit consists of a cell part with a resister and a capacitor connected in series and a measurement part having a resister. Then the resistance and the capacitance of the cell part are identified to calculate the electro-conductivity. The identification scheme is the least-square method with a forgetting factor calculated on-line. To avoid the effect of differentiation of measured signals, a filter is added to the identification method. The effectiveness of the proposed control scheme is shown by numerical simulation.</p

U-model-based two-degree-of-freedom internal model control of nonlinear dynamic systems

This paper proposes a U-Model-Based Two-Degree-of-Freedom Internal Model Control (UTDF-IMC) structure with strength in nonlinear dynamic inversion, and separation of tracking design and robustness design. This approach can effectively accommodate modeling error and disturbance while removing those widely used linearization techniques for nonlinear plants/processes. To assure the expansion and applications, it analyses the key properties associated with the UTDF-IMC. For initial benchmark testing, computational experiments are conducted using MATLAB/Simulink for two mismatched linear and nonlinear plants. Further tests consider an industrial system, in which the IMC of a Permanent Magnet Synchronous Motor (PMSM) is simulated to demonstrate the effectiveness of the design procedure for potential industrial applications