Thanit Trisuwannawat

PID Controller Design using Characteristic Ratio Assignment Method for Coupled-Tank Process

This paper presents the PID controller design for coupled-tank process using characteristic ratio assignment (CRA). The coupled-tank process is a challenge plant for testing the performance of PID controller because it is a high uncertainty nonlinear model. For this paper, the characteristic ratio assignment (CRA) which is satisfied specification of performance of control system. Furthermore, it is very convenient as a fast adjustment damping ratio as well as a high speed response. Finally, the simulation results can be illustrated the validity of our approach by MATLAB

Discrete time robust integral servo with PID × (n-2)/2 Stage PDA Controllers for unstable systems

This paper presents a design method for robustness stability results of unstable systems using forward controller employed to PID × (n-2)/2 Stages PDA Controllers which applied to integral servo problem, both continuous and discrete-time control systems, the root loci of this design method are shown the robustness results with the excellence transient response of this closed loop systems, moreover, in case of increasing controller loop gain, the system is still robustly stabilizable with better performance.

Discrete PID ×(n−2) stage PD cascade controller for SISO systems

This paper presents a design method for discrete-time parallel with continuous-time design for the nth order plant employing PID (Proportional-Integral-derivative) times(n-2) stage PD as a cascade controller. The controller is designed to meet the transient and steady state response specifications via the root locus approach. The results revealed that, if the sufficient sampling time for discrete-time system is available, all desired specifications are easily obtained.

I-P controller design for quadruple-tank system

A control system design with coefficient diagram method (CDM) is proven that effective for SISO control design. But the control system design for TITO via CDM is not concrete procedure. In this paper presents the control system design method for quadruple-tank process via CDM. By using the decentralized method for both non-minimum phase and minimum phase are made. The results from integral-proportional (I-P) controllers design via CDM and standard proportional-integral (PI) controls are also shown to compare the merits of the proposed controllers.

The Modified Quadruple-Tanks Process: A Flexible Mathematical Model with an Adjustable Simulink Block

This paper presents the modified quadruple-tanks process, a flexible laboratory process with an adjustable Simulink block, which is multivariable system consisting of four interconnected water tanks included with lower interacting valve. The new general form of modified quadruple-tanks mathematic model and Simulink block is developed for the advantage of control system analysis and design which can make practical use for many styles of multivariable process by adjusting the value of connected valve resistance, inlet and outlet valve ratio. In this paper described clearly about physical properties of modified quadruple-tanks process, mathematical modeling, transformation of modified quadruple-tanks process, analysis of right half-plane zeros characteristic and controller design for multivariable system. By the several models of transformed modified quadruple-tanks, they can be used to teach students in the skills of multivariable control system analysis and design, understanding control limitation due to interactions, model uncertainties, non-minimum phase behavior, and unpredictable time variations, design decentralized controllers, Implementing decouples to reduce the effect of interactions, and understanding their limitations.

Closed-form formulas for continuous/discrete-time PIDA controllers' parameters

This paper proposes the formulas for finding the Proportional gain, Integral gain and Derivative gain simultaneously of the PID controllers in both continuous-time and discrete-time systems. Once, the satisfied PID controller in continuous-time system is obtained. Then, just discretises it by using trapezoidal approximation or bilinear transformation, the discrete-time PID controller is easily achieved as well. The results from simulations revealed that this discrete-time controller provides a faster response than the continuous-time case.

Load swing control of an overhead crane

This paper proposed a controllers design method for controlling the load swing of an overhead crane. By addition of the quadratic derivative of state variables term in the usual standard performance index for Linear Quadratic Gaussian (LQG) optimal control as an extra weighting function to play the role in this task. The results revealed that the swing of the load can be decreased at numerous requirements with excellence. How to select the suitable weights for control is also suggested.

Following control of hard disk drive using derivative state constrained optimal H 2 controls

The author presents following control of the hard disk drive using derivative state constrained optimal H2 controls (H2ẋ). The study in this paper concern to the control amount of NRPE (non repeatable position error) and PES (position error signal) of track following control in the hard disk drive process by the effective method. The derivative state constrained optimal H2 control (H2ẋ) has been formulated to suppress the rate of changes of state variables. It is suitable for the oscillated system and able to be used in non linear system. Thus, the derivative state constrained optimal H2 control (H2ẋ) has been applied to track following control in the hard disk drive for increasing the accuracy of head positioning by decreasing the effect from oscillation, variation and non linearity characteristic in its system. Finally, the simulation results show that our proposed method can satisfy the design specifications of track following servo control system effectively.

Development of Inverted Pendulum System at KMITL

This paper presents the development of Inverted Pendulum System at King Mongkuts Institute of Technology Ladkrabang (KMITL), including the designing, construction and control system design. The stabilizing of an unstable system in optimal control scheme via state-space approach is applied. The LQG controller design examples including the addition of the quadratic derivatives of state variables term in the usual standard performance index for linear quadratic Gaussian optimal control as an extra weighting function to play the role in swing suppressor is presented. Finally, a new inverted pendulum system nearly SEGWAY function is shown in this paper.

Discrete-time PIDA controller designed by Kitti's method; a third generation

This paper proposes the design of Discrete-Time PIDA (Proportional-Integral-Derivative-Acceleration) controller. Once, the satisfied PIDA controller in Continuous-Time system is obtained. Then, just discretises it by using trapezoidal approximation or bilinear transformation, the Discrete-Time PIDA controller is easily achieved as well. The root loci of the closed-loop systems are circular shapes in both s-Plane and z-Plane implied that increasing of the open loop gains, the faster and smaller in percent overshoot can be obtained. Comparing among three generations are shown that the third generation of Discrete-Time PIDA controller is the simplest way in design without the difficulty to place the zeros of the controller in z-Plane as in the second generation when the sampling time is too small.