LQG controller designs from reduced order models for a launch vehicle

The suppression of liquid fuel slosh motion is critical in a launch vehicle (LV). In particular, during certain stages of the launch, the dynamics of the fuel interacts adversely with the rigid body dynamics of the LV and the feedback controller must attentuate these effects. This paper describes the effort of a multi-variable control approach applied to the Geosynchronous Satellite Launch Vehicle (GSLV) of the Indian Space Research Organization (ISRO) during a certain stage of its launch. The fuel slosh dynamics are modelled using a pendulum model analogy. We describe two design methodologies using the Linear-Quadratic Gaussian (LQG) technique. The novelty of the technique is that we apply the LQG design for models that are reduced in order through inspection alone. This is possible from a perspective that the LV could be viewed as many small systems attached to a main body and the interactions of some of these smaller systems could be neglected at the controller design stage provided sufficient robustness is ensured by the controller. The first LQG design is carried out without the actuator dynamics incorporated at the design stage and for the second design we neglect the slosh dynamics as well

STUDIES ON DEVELOPMENT OF SUSTAINED RELEASE DILTIAZEM HYDROCHLORIDE MATRICES THROUGH JACKFRUIT MUCILAGE

Objective: The sustained release of drug from dosage form is useful especially for achieving controlled plasma level of the drug as well as improving bioavailability. The objective of the present work was to develop sustained release diltiazem hydrochloride matrix tablets using natural polymers and gums like jackfruit mucilage and tamarind polysaccharide. Methods: Tablets were prepared by direct compression method and evaluated for various physical parameters. Direct compression method using response surface methodology, followed by optimization of the evaluation parameters were employed to get final optimized formulation. Results: Among all formulations, M2 shows 92.87% better controlled release at the end of 12 hrs. The release co-efficient values ‘n' (>0.5) indicated that the drug release followed non fickian anomalous mechanism based on formulation factors. The stability studies were carried out according to ICH guideline which indicates that the selected formulation was stable. Conclusion: Diltiazem HCl matrices could be developed with desirable release modulation for a once daily administration