Manfred Morari - US grants

This work will apply robust controllers developed to handle aerospace problems to the chemical process industries. Robust controllers perform a required task even though the mathematical model of the system to be controlled might be a poor one. The reachers will try to adapt and improve synthesis, and combine it with internal model control (IMC) now being successfully used for chemical plant control. The specific issues to be addressed include: (1) mathematical formulation of practical control problems suitable for synthesis; (2) qualitative understanding of the factors determining the optimal solution; (3) alternate controller parametrization; and (4) contrained control.

A crossdisciplinary effort between the PI and John Doyle's group in electrical engineering has resulted in the development of some outstanding control algorithms and real usable software. Funds provided in this grant are to upgrade the PI's computer facilities to foster further developments in this area by providing him and his students a SUN microcomputer system including a file server and two workstations. The specific projects to benefit from the new equipment will include a) Analysis and synthesis of robust multivariable control systems for nonlinear closed loop systems often operated at the intersection of a set of complex constraints. Systems studied include complex distillation configurations and packed bed reactors. b) On-line optimization via computers with distribute processors. The PI will be able to contribute to the development of the "cosmic cube" (which involves 64 processors connected in the form of a Boolean cube) and is using it to study the optimal compressor operation of gas transmission pipelines. c) Development of a user-friendly expert system for robust control system design. The PI and his co-workers have already developed some software but it requires expertise on the part of the user. Further research will enable practicing engineers to use this software.

This project intends to provide an important framework for major genetic restructuring of central carbon metabolism in E. coli for the purpose of increasing synthesis of valuable products. This project also plans to contribute to new monitoring and analysis methods of general utility in studying cell response to environmental or genetic manipulation. The specific overall objective of this project is to reduce acetate formation during aerobic growth of E. coli by genetic modification of carbon flow. This is to be done by: - Identifying metabolic signals which are candidates for directing carbon flow towards acetate. - Identifying proteins associated with responses at the genetic level to environments which trigger acetate production. - Evaluating overall glucose consumption, growth and acetate formation kinetics and stoichiometry under conditions which result in acetate production. - Characterizing in detail several existing genetic constructs which possess or which are likely to exhibit altered acetate production metabolism. - Identifying and mapping new genetic alterations which enhance growth in acetate-producing environments.

This research project is aimed at developing process control algorithms to handle both constraints and uncertainty. Constraints affect controller design because while the dynamic behavior of many processes can be accurately described by a linear model, system operation is always subject to constraints which are nonlinear elements. The controller has to be designed to handle these nonlinearities. Such constraints may arise from actuator saturation or processing limitations (certain temperatures and pressures may not be exceeded, for example). Uncertainty is a factor because the control designer never has a perfect dynamic description (model) of any real industrial process. The system is approximated and model order and parameters always contain some error, and may even change with operating conditions. The PI plans to implement two techniques for dealing with such problems, Model Predictive Control (MPC) and Anti-Windup Bumpless-Transfer (AWBT). MPC requires that the control objective is expressed in terms of a single quadratic objective function and the constraints are translated into linear inequality constraints. AWBT controller design proceeds in two steps where first an acceptable linear robust controller is designed neglecting all nonlinear loop elements and objectives. Then a compensation scheme is added which deals with the nonlinear issues such as constraints. This research will proceed in three steps: (1) A new robust linear MPC controller will be designed. It will be implemented in a nonlinear manner through an optimizer which aims at satisfying all process constraints while minimizing the deviation from linear behavior. (2) Development of an AWBT synthesis procedure that balances the trade-offs between smooth switching performance, measurement noise sensitivity and robustness. (3) Development of mechanisms to translate practical objectives and constraints into an MPC or AWBT formalism in an effective manner.

9315537 Morari This award of $200,000 is for curriculum development in control systems. Traditional introductory undergraduate courses in control theory do not capture the recent developments in research and still tend to be a collection of tricks without a coherent theme. Moreover, control theory has become very interdisciplinary and now has no natural home within the traditional engineering disciplines. Yet because of the increasingly important role that the design of control into engineered devices and processes that modern advances in computers and communications is making possible, it is now very important to introduce modern control theory and techniques to undergraduates. This proposal will develop modular curricula for two control courses at the senior level, involving both theory and experimentation. Two experiments that can be run remotely will be developed for the courses, control in buildings and control of a ducted fan engine.

This US-Brazil Cooperative Science award will support collaboration of Manfred Morari, California Institute of Technology; Anthony Skjellum, University of California Lawrence Livermore National Laboratory; Evaristo Biscaia, Federal University of Rio de Janeiro; and Argimiro Secchi, Federal University of Rio Grande do Sul, Brazil. The project aims to make a comparative analysis of alternatives for dynamic simulation of chemical processes on computers with parallel architectures and supercomputers. Chemical process simulation is responsible for many CPU cycles used on mini and mainframe computers. Simulation models describing industrial processes of realistic complexity translate into problems of very large dimension, and high-speed simulators are required to make these simulations feasible. Thus, high-speed computers must be used, and simulators suitable for these computers must be developed. In this project, the researchers will consider a range of industrial problems in order to improve the performance of the developed algorithms and provide more reliable comparisons with commercial dynamic simulators. The mutual benefits of this project will accrue from the Brazilian side's expertise in dynamic simulation, and the US side's computing facilities at Caltech.

This NSF award will be utilized to renovate approximately 5,600 square feet of research space in the Steele Laboratory of Electrical Sciences on the campus of the California Institute of Technology. Steele Lab is approximately 30 years old, and the renovation will retrofit the facility to the changed emphasis of Cal Tech electrical engineering research programs. In addition, it will consolidate researchers into one facility to work together on interdisciplinary projects in communications and automatic control. All seven project faculty have joined the faculty in the last ten years. Specific renovation activities include construction of a unique high bay area to house a flexible structure experiment as well as a distillation column of sufficient size to mimic actual industrial problems. A local area network will be established to increase researcher interaction and to overcome the inefficiencies associated with use of the campus backbone system which is approaching maximum capacity. The project will have an important impact on faculty growth and student enrollment, including minorities and women, in the competitive area of communications and automatic control.