초록 ▼

An attitude control loop for a spacecraft uses a proportional-integral-derivative (PID) controller for control about an axis. The spacecraft body has at least a primary mechanical resonance. The attitude sensors are collocated, or both on the rigid portion of the spacecraft. The flexure attributable

An attitude control loop for a spacecraft uses a proportional-integral-derivative (PID) controller for control about an axis. The spacecraft body has at least a primary mechanical resonance. The attitude sensors are collocated, or both on the rigid portion of the spacecraft. The flexure attributable to the resonance may result in instability of the system. A compensator for the control loop has an amplitude response which includes a component which rolls off beginning at frequencies below the resonance, and which also includes a component having a notch at a notch frequency somewhat below the resonant frequency. The phase response of the compensator tends toward zero at low frequencies, and tends toward -180°as frequency increases toward the notch frequency. At frequencies above the notch frequency, the phase decreases from +180°, becoming more negative, and tending toward -90°at frequencies far above the resonance frequency. Near the resonance frequency, the compensator phase is near zero.

대표청구항 ▼

An attitude controller for a spacecraft having a body defining at least a primary self-resonant frequency, comprising: torquing means coupled to the spacecraft body for generating torques for changing the attitude of said spacecraft; sensing means coupled to said body for sensing the attitude thereo

An attitude controller for a spacecraft having a body defining at least a primary self-resonant frequency, comprising: torquing means coupled to the spacecraft body for generating torques for changing the attitude of said spacecraft; sensing means coupled to said body for sensing the attitude thereof and for generating deviation signals indicative of the deviation of the attitude away from a desired attitude; PID control means for operating on attitude error signals for summing first, second and third products, said first product being formed by multiplying a first constant by said attitude error signals, said second product being formed by multiplying a second constant by the time derivative of said attitude error signals, and said third product being formed by multiplying a third constant by the time integral of said attitude error signals; coupling means coupled to said torquing means, said sensing means and said PID control means for coupling said PID control means in a control path responsive to said attitude error signals, and extending from said sensing means to said torquing means, for stabilizing said attitude, said coupling means further including compensation means cascaded with said PID control means, said compensation means having a transfer characteristic including a gain function which is substantially constant below a frequency of about w7, which gain function includes (a) a component representing a monotonic decrease in gain with increasing frequency from said frequency w7, superimposed upon (b) a notch component at a frequency of www7, and which progressively lags toward -180 degrees with frequency increasing from w7 toward w180 degrees at w90 degrees at frequencies far above w