Balasubrahmanya Srinivasan

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J. V. Kadam, W. Marquardt Lehrstuhl für Prozesstechnik, RWTH Aachen University, Turmstr. 46, 52064 Aachen, Germany B. Srinivasan, D. Bonvin Laboratoire d’Automatique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland Optimization of Transitions in Industrial Polymerization Processes using Solution Models Increasing demand on delivering on-spec product, higher operating costs and diminishing profit margins in the polymerization industry require cost- optimal process operation. This has

This paper addresses the steady-state optimization of continuous processes in the presence of uncertainty in the form of unknown or time-varying model parameters, structural plant-model mismatch, and disturbances. To address these issues, we assume that ce ...

Predictive Control of Unstable Nonminimum-phase Systems K. Guemghar, B. Srinivasan, Ph. Mullhaupt, D. Bonvin ´ Institut d’Automatique, Ecole Polytechnique F´d´rale de Lausanne, ee CH-1015 Lausanne, Switzerland. Predictive control is a very eﬀective approach for tackling problems with constraints and nonlinear dynamics, especially when the analytical computation of the control law is diﬃcult. Standard predictive control involves predicting the system behavior over a prediction horizon and calculating the inp

In industrial polymerization processes, several grades of polymer are frequently produced in the same plant by changing the operating conditions. Transitions between the different grades are rather slow and result in the production of a considerable amount ...

Reaction systems are typically represented by first-principles models that describe the evolution of the states (typically concentrations, volume and temperature) by means of conservation equations of differential nature and constitutive equations of algeb ...

Interplay between Identiﬁcation and Optimization in Run-to-run Schemes B. Srinivasan, D. Bonvin ´ Institut d’Automatique, Ecole Polytechnique F´d´rale de Lausanne, ee CH-1015 Lausanne, Switzerland. Optimization of batch processes has received increasing attention since its provides an uniﬁed framework to improve productivity without violating constraints on safety, selectivity, reproducability, etc. Due to uncertainties (disturbances and modeling errors) that are invariably present at the industrial level,

In the framework of process optimization, the use of measurements to compensate the effect of uncertainty has re-emerged as an active area of research. One of the ideas therein is to adapt the inputs in order to track the active constraints and push certai ...

Solving a multi-input dynamic optimization of a batch processes is a complex problem involving interactions between input variables and constraints over time. The problem gets more difficult due to the presence of local solutions that have almost the same ...

Target factor analysis (TFA) has been used successfully with reaction data to determine, without knowledge of reaction kinetics, the number of independent reactions and the corresponding stoichiometries. This paper analyzes the applicability of TFA techniques to reaction data on the basis of concentration measurements. It is shown that, in some cases, a data matrix that is well suited to existing TFA techniques can be constructed from concentration measurements, material exchange terms, and initial conditio

The problem of swinging up an inverted pendulum on a cart and controlling it around the upright position has traditionally been treated as two separate problems. This paper proposes a control strategy that is globally asymptotically stable under actuator s ...

OPTIMIZATION OF A SEMI-BATCH REACTION SYSTEM UNDER SAFETY CONSTRAINTS O. Ubrich+, B. Srinivasan*, F. Stoessel+, D. Bonvin* * Novartis Services AG, CH-4002 Basel, Switzerland Institut d’ utomatique, Ecole Polytechnique Fédérale de Lausanne A CH-1015, Lausanne, Switzerland * Fax: +41 21 693 2574 and e-mail: dominique.bonvin@epfl.ch + An important objective in the chemical industry is to find the operating conditions that maximize profit while ensuring safe operation. The safety considerations arise from the e

In fluidized-bed gas-phase polymerization reactors, several grades of polyethylene are produced in the same equipment by changing the operating conditions. Transitions between the different grades are rather slow and result in the production of a considera ...

The control of the current, position and shape of an elongated cross-section tokamak plasma is complicated by the so-called instability of the current vertical position. Linearized models all share the feature of a single unstable eigenmode, attributable t ...

The aim of this paper is to present a global approach to dynamic optimization of batch emulsion polymerization reactors using a stochastic optimizer. The objective is to minimize the final batch time with constraints on the final conversion and molecular w ...

In real-time optimization, enforcing the constraints that need to be active is important for optimality. In fact, it has been established in the context of parametric variations that, if these constraints are not satisfied, the optimality loss would be O($ ...

The concept of reaction invariants is extended to include flow invariants of chemical-reaction systems with inlet and outlet streams. A transformation to normal form is introduced that allows the separation of (1) the evolution of the independent reactions, (2) the influence of inlet streams, and (3) the behavior of the reaction and flow invariants. In the light of this transformation to normal form, model reduction, state accessibility, state reconstruction, and feedback linearizability are analyzed.

This paper considers a helicopter-like setup called the Toycopter. Its particularities reside first in the fact that the toycopter motion is constrained to remain on a sphere and second in the use of a variable rotational speed of the propellers to vary th ...

Run-to-run control is a technique that exploits the repetitive nature of processes to iteratively adjust the inputs and drive the run-end outputs to their reference values. It can be used to control both static and finite-time dynamic systems. Although the ...

Improving the productivity of fed-batch filamentous fungal fermentations can be formulated as a dynamic optimization problem. However, numerical optimization based on a nominal process model is typically insufficient when uncertainty in the form of model m ...

Optimal Operation of Batch Processes with Multiple Inputs and Constraints B. Srinivasan, S. Palanki, and D. Bonvin Optimal operation of batch processes has become increasingly important in recent years in the face of increased competition and also due to the trend towards building small, flexible plants n e a r the markets of consumption. Traditionally, batch processes have been operated with rudimentary control loops, which hinders the implementation of best operating policies in t h e face of uncertainty.

Balasubrahmanya Srinivasan

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Dynamic Real-Time Optimization of Transitions in Industrial Polymerization Processes using Solution Models

110th Anniversary: A Feature-Based Analysis of Static Real-Time Optimization Schemes

Predictive Control of Fast Unstable and Nonminimum-phase Nonlinear Systems

Optimal Grade Transition in Industrial Polymerization Processes via NCO Tracking

Minimal State Representation for Open Fluid-Fluid Reaction Systems

Interplay between Identification and Optimization in Run-to-run Schemes

Optimizing Control Based on Output Feedback

On the various local solutions to a two-input dynamic optimization problem

Target Factor Analysis of Reaction Data: Use of Data Pre-treatment and Reaction-Invariant Relationships

Global Stabilization of an Inverted Pendulum – Control Strategy and Experimental Verification

Optimization of a Semi-Batch Reaction System under Safety Constraints

Optimal grade transition for polyethylene reactors via NCO tracking

Improving tokamak vertical position control in the presence of power supply voltage saturation

Dynamic optimization of batch emulsion polymerization using simulated annealing

How Important is the Detection of Changes in Active Constraints in Real-Time Optimization?

Reaction and Flow Variants/Invariants in Chemical Reaction Systems with Inlet and Outlet Streams

Control of the Toycopter using a Flat Approximation

A Globally Convergent Algorithm for the Run-to-Run Control of Systems with Sector Nonlinearities

Run-to-run Optimization of Filamentous Fungal Fermentation

Optimal Operation of Batch Processes with Multiple Inputs and Constraints