B. Srinivasan

Optimal Feed Profile for a Second-order Reaction in a Semi-batch Reactor under Safety Constraints - Experimental Study

Abstract Maximising the yield of the second order reaction (2-butanol+propionic anhydride) by manipulating the inlet flow rate is considered for an isothermal semi-batch process. First a procedure for the determination of the kinetic parameters using coupled spectroscopic and calorimetric methods is presented. Then an optimisation of the reaction system is performed numerically and verified experimentally. Constraints on the amount of heat produced and on the temperature attainable in the case of cooling failure are imposed for safety consideration.

Control of the Toycopter Using a Flat Approximation

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 the propeller thrust. A complete model using Lagrangian mechanics is derived. The Toycopter is shown to be nondifferentially flat. Nevertheless, by neglecting specific cross-couplings, a differentially flat approximation can be generated and used for controller design, provided the controller gains do not exceed certain bounds that are given explicitly. The achieved performance is better than with standard linear controllers, especially during large displacements that induce strong nonlinear gyroscopical forces. The results are illustrated both in simulation and experimentally on the setup.

On the nonminimum-phase characteristics of two-link underactuated mechanical systems

Underactuated mechanical systems are those which possess fewer actuators than the number of degrees of freedom. It is shown that, except for some pathological cases, exclusively kinetic, two-link underactuated mechanisms are of nonminimum phase when the natural outputs are considered.