Patent ID: 6205378
Filing Date: 2001-03-20
Classification: B64G

Abstract:
An attitude control system operative with a thruster for controlling attitude of a vehicle carrying the thruster, wherein the thruster comprises a valve enabling the formation of pulses of expelled gas from a source of compressed gas, the system comprising:means for gathering data of the attitude of the vehicle, wherein the vehicle is located within a force field tending to orient the vehicle in a first attitude;means for driving the thruster to expel a succession of pulses of gas, wherein an individual one of the pulses of gas provides a force impulse which urges the vehicle toward a desired attitude different from the first attitude, the force field causing the vehicle to drift back towards the first attitude during an interval of time between successive ones of the gas pulses;means for evaluating the attitude data to determine a pattern of values of attitude of the vehicle in response to the gas pulses and in response to the force field, the control system being operative to maintain the attitude within a predetermined band of values of attitude which includes the desired attitude;means for determining if said pattern is within bounds of said band;means for establishing an optimal duration of each of the gas pulses based on the pattern of values of attitude, the optimal duration providing for a minimal number of opening and closure operations of the valve; andwherein the establishing means communicates the optimal duration to the driving means for driving the thruster to provide a gas pulse with the optimal duration; andsaid establishing means, in response to a determination from said determining means, is operative to adjust the pulse duration dependent on a periodicity of said pattern when said pattern is confined within said band, and is operative to adjust the pulse duration dependent on a closest point of approach of said pattern to a boundary of said band when said pattern is confined within said band and upon an occurrence of generation of torque on said vehicle by a source of torque.