Accession Number : AD0820727

Title :   PERFORMANCE CHARACTERISTICS OF A DAMPED MASS EXPULSION ATTITUDE CONTROL SYSTEM SUBJECTED TO EXTERNAL DISTURBANCES AND SYSTEM ERRORS.

Descriptive Note : Rept. for Apr-Jul 66,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA EL SEGUNDO TECHNICAL OPERATIONS

Personal Author(s) : Englehart, William C.

Report Date : MAR 1967

Pagination or Media Count : 116

Abstract : A new mass-expulsion approach to space vehicle attitude control is introduced which shows promise of reducing propellant consumption and pulsing frequency plus providing better acquisition performance (time and propellant) and attitude accuracy than present minimum-impulse type controllers. This new 'damped' attitude control logic was designed to take advantage of existing disturbance torques in damping the vehicle's position and rate. The controller attains the improved performance by adaptive logic which drives the vehicle near the minimum fuel expenditure trajectory each control cycle. The simple adaptive compensation scheme based on the immediate past history of pulses is included to correct for biased and time-variant disturbance torques, propulsive and sensing errors, and time-variant moments of inertia. Results of the first phase of study concerning this controller are included herein. A single axis kinematic digital computer simulation, which included constant disturbance-torque coefficients, was utilized. This simulation is described. The limit-cycle and acquisition performance of the 'damped' control logic is compared with pseudo-rate control logic in the presence of propulsive errors, sensing errors, and external disturbance torques. Since the preliminary results point out the need for further consideration of the 'damped' control logic, parametric investigations and comparison with other systems are being obtained with the aid of a wire table simulation and a three-axis dynamic vehicle digital compter simulation. (Author)

Descriptors :   (*ATTITUDE CONTROL SYSTEMS, SPACECRAFT), FUEL CONSUMPTION, PROPELLANT CONTROL, DAMPING, TORQUE, ADAPTIVE CONTROL SYSTEMS, DIGITAL COMPUTERS, COMPUTER PROGRAMS, COMPUTER LOGIC, CONTROL SEQUENCES, ERRORS, CONTROL JETS.

Subject Categories : Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE