Secondary Injection Thrust Vector Control Power Plant Linearisation using Fuzzy Logic for a Launch Vehicle
Keywords: Secondary injection thrust vector control system, launch vehicle, fuuy logic. nonlinear plant model, fuzzy inference system, control power plant, control loop, fuzzy inference system. pre-compcnsalor
AbstractControl forces are required for steering a launch vehicle to guide it to follow an optimal trajectory. Launch vehicle control involves two control loops, the inner loop deals with short-period dynamics, stability and the outer loop, known as the guidance loop, optimises the trajectory. The general nonlinear plant model is first approximated as a linear time-varying plant over a nominal trajectory and then segmented as linear, time-invariant plant models at different time intervals. A major part of the plant model is the control power plant, which for a secondary injection thrust vector control system used for the solid booster stage of a launch vehicle is nonlinear due to various reasons. The controllers designed for different time regimes assume the control power plant as linear and are adapted smoothly by a technique called gain scheduling to cope with the plant model changes wrt time. In this paper, a fuzzy logic-based pre-compensator is developed to linearise the control power plant so that the controller design becomes valid. Simulation results are presented to validate the design and a novel preprocessing technique is developed to reduce the size of the fuzzy inference system.
How to Cite
Rani, S., Sibi, S., & Mohanlal, P. (2002). Secondary Injection Thrust Vector Control Power Plant Linearisation using Fuzzy Logic for a Launch Vehicle. Defence Science Journal, 52(4), 409-416. https://doi.org/10.14429/dsj.52.2198
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