Analytical design of an industrial two-term controller for optimal regulatory control of open-loop unstable processes under operational constraints

Tchamna, Rodrigue,Lee, Moonyong Elsevier 2018 ISA transactions Vol.72 No.-

<P><B>Abstract</B></P> <P>This paper proposes a novel optimization-based approach for the design of an industrial two-term proportional-integral (PI) controller for the optimal regulatory control of unstable processes subjected to three common operational constraints related to the process variable, manipulated variable and its rate of change. To derive analytical design relations, the constrained optimal control problem in the time domain was transformed into an unconstrained optimization problem in a new parameter space via an effective parameterization. The resulting optimal PI controller has been verified to yield optimal performance and stability of an open-loop unstable first-order process under operational constraints. The proposed analytical design method explicitly takes into account the operational constraints in the controller design stage and also provides useful insights into the optimal controller design. Practical procedures for designing optimal PI parameters and a feasible constraint set exclusive of complex optimization steps are also proposed. The proposed controller was compared with several other PI controllers to illustrate its performance. The robustness of the proposed controller against plant-model mismatch has also been investigated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Optimal regulatory control of open-loop unstable process under operational constraints. </LI> <LI> An optimization based approach to find a global optimal solution of control system. </LI> <LI> The proposed method can handle operational constraints explicitly in controller design. </LI> <LI> The analytical design offers many useful insights to process control practitioners. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Optimization approach for the analytical design of an industrial PI controller for the optimal regulatory control of first order processes under operational constraints

Tchamna, Rodrigue,Lee, Moonyong Elsevier 2017 Journal of the Taiwan Institute of Chemical Engine Vol.80 No.-

<P><B>Abstract</B></P> <P>In this paper, an optimization-based approach for the closed-form design of an industrial proportional-integral (PI) controller was proposed for the optimal regulatory control of first order process under three typical operational constraints. An ingenious parameterization with Lagrangian multiplier method was used to convert the constrained optimal control problem in the time domain to an unconstrained optimization problem to derive an analytical solution for the optimal regulatory control. Three typical operational constraints could be taken into account in the controller design stage, explicitly. The proposed analytical design method required no complicated optimization steps and guaranteed global optimal closed-loop performance and stability. The proposed analytical approach also provides useful insights into the optimal controller design and analysis. A practical and facile procedure for designing optimal PI parameters and a feasible constraint set was also proposed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Analytical design of a PI controller for chemical processes is proposed. </LI> <LI> The controller handles the control performance and the operational constraints. </LI> <LI> The controller shows the connection between the plant and controller parameters. </LI> <LI> A procedure is provided, helping to know if a given constraint set is feasible. </LI> <LI> If the constraint set cannot be satisfied, the procedure suggests how to tune it. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The proposed PI controller design guarantees global optimal regulatory closed-loop performance and stability requiring no complicated optimization steps </P> <P>[DISPLAY OMISSION]</P>

Constraint handling optimal PI control of open-loop unstable process: Analytical approach

Tchamna, Rodrigue,Lee, Moonyong Springer-Verlag 2017 Korean Journal of Chemical Engineering Vol.34 No.12

<P>This paper proposes the closed-form analytical design of proportional-integral (PI) controller parameters for the optimal control of an open-loop unstable first order process subject to operational constraints. The main idea of the design process is not only to minimize the control performance index, but also to cope with the constraints in the process variable, controller output, and its rate of change. To derive an analytical design formula, the constrained optimal control problem in the time domain was transformed to an unconstrained optimization in a parameter space associated with closed-loop dynamics. By taking advantage of the proposed analytical approach, a convenient shortcut algorithm was also provided for finding the optimal PI parameters quickly, based on the graphical analysis for the optimal solution of the corresponding optimization problem in the parameter space. The resulting optimal PI controller guarantees the globally optimal closed-loop response and handles the operational constraints precisely.</P>

Analytical design of constraint handling optimal two parameter internal model control for dead-time processes

Rodrigue Tchamna,Muhammad Abdul Qyyum,Muhammad Zahoor,Camille Kamga,Ezra Kwok,이문용 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.3

This work presents an advanced and systematic approach to analytically design the optimal parameters of a two parameter second-order internal model control (IMC) filter that satisfies operational constraints on the output process, the manipulated variable as well as rate of change of the manipulated variable, for a first-order plus dead time (FOPDT) process. The IMC parameters are designed to minimize a control objective function composed of the weighted sum of the error between the process variable and the set point, and the rate of change of the manipulated variable, and to satisfy the desired constraints. The feasible region of the constrained IMC control parameters was graphically analyzed, as the process parameters and the constraints varied. The resulting constrained IMC control parameters were also used to find the corresponding industrial proportional-integral controller parameters of a Smith predictor structure.

Simplified design of proportional-integral-derivative (PID) controller to give a time domain specification for high order processes

Rodrigue Tchamna,이문용 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.4

An efficient simplified method is proposed for the time domain design of industrial proportional-integralderivative (PID) controllers and lead-lag compensators for high order single input single output (SISO) systems. The proposed analytical method requires no trial error steps for a lead-lag compensator design in the time domain by using the root-locus method. A practical PID controller design method was obtained based on the corresponding lead-lag compensator to give a required time-domain specification. Simulation studies were carried out to illustrate the control performance of the controllers by the proposed method. The proposed PID controller and lead-lag compensator directly satisfied time domain control specifications such as damping ratio, maximum overshoot, settling time and steady sate error without trial and error steps. The suggested algorithm can easily be integrated with a toolbox in commercial software such as Matlab.

Analytical Design of Optimal Control for Open-loop Unstable Process with Operation Constraints

Rodrigue Tchamna,이문용 제어로봇시스템학회 2017 제어로봇시스템학회 국내학술대회 논문집 Vol.2017 No.5

YAW RATE AND SIDE-SLIP CONTROL CONSIDERING VEHICLE LONGITUDINAL DYNAMICS

R. TCHAMNA,윤일중 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.1

Most conventional vehicle stability controllers operate on the basis of many simplifying assumptions, such as a small steering wheel angle, constant longitudinal velocity and a small side-slip angle. This paper presents a new approach for controlling the yaw rate and side-slip of a vehicle without neglecting its longitudinal dynamics and without making simplifying assumptions about its motion. A sliding-mode controller is used to develop a differential braking controller for tracking a desired vehicle yaw rate for a given steering wheel angle, while keeping the vehicle’s side-slip angle as small as possible. The trade-off that exists between yaw rate and side-slip control is described. Conventional and proposed algorithms are presented, and the effectiveness of the proposed controller is investigated using a seven-degree-of-freedom vehicle dynamics model. The simulation results demonstrate that the proposed controller is more effective than the conventional one.

Investigation Of Coupling Effect Between Steering Wheel Input And Suspension System For Vehicle Attitude Control

Rodrigue Tchamna,Iljoong Youn 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

Realistic models for ground vehicle attitude control need to take into account coupling effect between steering wheel input and suspension system. Control design based on vehicle models such as bicycle models can work for small operation range, but can become critical when the effects of suspension become important. This paper deals with investigation of coupling effect between steering wheel input and suspension system and the result of those effects on the orientation of the vehicle. The goal of this investigation being effective control designing for attitude control of the vehicle. Most of control methods nowadays employed for attitude control of vehicles are active anti-roll bars, active steering and electronic brake mechanism. In this paper, only vertical actuators locating on each suspension are used to control the attitude of the vehicle due to any given steering input during cornering. The resulting model is a set of highly nonlinear equations that allow studying deeply all aspect of vehicle dynamics, including ride comfort, handling, road holding, and attitude control of the chassis during straight path motion as well as cornering. The model developed here is 15 degrees of freedoms (d.o.f.) model, 6 d.o.f. for the chassis, 2 × 4 d.o.f. for each of the four wheels and 1 d.o.f. for the steering wheel. A controller is designed and simulations are carried out.

Attitude Control of a Full Vehicle in Cornering

Rodrigue Tchamna,Yuli Amalia Husnil,Riezqa Andika,Moonyong Lee 제어로봇시스템학회 2014 제어로봇시스템학회 국내학술대회 논문집 Vol.2014 No.5

A STUDY OF LINKED STAR OPERATIONS

Paudel, Lokendra,Tchamna, Simplice Korean Mathematical Society 2021 대한수학회보 Vol.58 No.4

Let R ⊆ L ⊆ S be ring extensions. Two star operations ${\ast}_1{\in}Star(R,S)$, ${\ast}_2{\in}Star(L,S)$ are said to be linked if whenever $A^{{\ast}_1}= R^{{\ast}_1}$ for some finitely generated S-regular R-submodule A of S, then $(AL)^{{\ast}_2}=L^{{\ast}_2}$. We study properties of linked star operations; especially when ${\ast}_1$ and ${\ast}_2$ are strict star operations. We introduce the notion of Prüfer star multiplication extension ($P{\ast}ME$) and we show that under appropriate conditions, if the extension R ⊆ S is $P{\ast}_1ME$ and ${\ast}_1$ is linked to ${\ast}_2$, then L ⊆ S is $P{\ast}_2ME$.