Rate control system algorithm developed in state space for models with parameter uncertainties
doi: 10.5028/jatm.2011.03033511

Adilson Jesus Teixeira*
Institute of Aeronautics and Space
São José dos Campos/SP – Brazil
adilsonajt@iae.cta.br

*author for correspondence

Abstract:
Researching in weightlessness above the atmosphere needs a payload to carry the experiments. To achieve the weightlessness, the payload uses a rate control system (RCS) in order to reduce the centripetal acceleration within the payload. The rate control system normally has actuators that supply a constant force when they are turned on. The development of an algorithm control for this rate control system will be based on the minimum-time problem method in the state space to overcome the payload and actuators dynamics uncertainties of the parameters. This control algorithm uses the initial conditions of optimal trajectories to create intermediate points or to adjust existing points of a switching function. It associated with inequality constraint will form a decision function to turn on or off the actuators. This decision function, for linear time-invariant systems in state space, needs only to test the payload state variables instead of spent effort in solving differential equations and it will be tuned in real time to the payload dynamic. It will be shown, through simulations, the results obtained for some cases of parameters uncertainties that the rate control system algorithm reduced the payload centripetal acceleration below μg level and keep this way with no limit cycle.

Keywords:

Rate control, Off-on control, Time optimal control, State space, Bang-bang control.

J. Aerosp.Technol. Manag., São José dos Campos, Vol.3, No.3, pp. 259-268, Sep. - Dec., 2011
Received: 04/08/11
Accepted: 06/10/11