Estudos de um método para cálculo de ganhos da malha de controle de atitude de um lançador de satélites / Analytical method for computing the controller gains of a satellite launcher

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

In this work, the VLS (Satellite Launcher Vehicle) control gains are calculated applying a frozen poles technique for each 1-second interval, allowing that a linear time invariant analysis to be executed inside each time interval during all flight phases. The system control architecture is proportional-integral with derivative feedback, making the 3 gains (pitch axis) to be scheduled with time so that the launcher can achieve the performance and stability requirements for the mission. A LQ (Linear Quadratic) methodology is applied for a chosen time instant, achieving a reference model that is adopted for all instants. However, making use of the 3 controller gains, it is not possible in each time to freeze all parameters of the model. This way, the controlled model varies during the flight and degenerates the attitude control in comparison with the reference model. Also, the specification of the weighting matrixes is an extremely empirical procedure, has poor physical meaning and relation with the time response. In this work, an analytic method is used for the determination of the gains, establishing the time response parameters: rising time, settling time and maximum ramp error. This way, the poles and zeros are free to move (respecting the variable "nature" of this system), regarding only the time requirements. This method appears to be better than the LQ method already in use, since it allows a corresponding between the adjustable parameters and the time response and has larger phase and gain margins.

ASSUNTO(S)

spacecraft launching regulador quadrático linear linear quadratic regulator automatic flight control engenharia e tecnologia espacial veículos lançadores siso (control systems) controle de atitude attitude control launch vehicles nonlinear systems engineering and space technology controle automático de vôo lançamento de satelites sistemas de controle siso sistemas não-lineares

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