Accession Number : ADA180606

Title :   Suboptimal Control of Large Flexible Space Structures Experiencing Rotational Dynamics Nonlinearities.

Descriptive Note : Final rept.,

Corporate Author : ARMY MILITARY PERSONNEL CENTER ALEXANDRIA VA

Personal Author(s) : Mitroka,George D.

Report Date : 08 MAY 1987

Pagination or Media Count : 102

Abstract : This report first develops a method to determine a suboptimal smooth trajectory for large flexible space structures during rotational slewing maneuvers. The method consists of minimizing the quadratic integral of the corresponding second time derivative of the generalized coordinate subject to specified boundary conditions. A parametric study examined the consequences of varying the number of design parameters and the number of specified boundary conditions. Study results include: 1) Additional degrees of freedom reduce the curvature of the trajectory, reduce the peak maneuver angle rate and only slightly increase the peak rigid-body torques on the structure during slewing maneuvers; 2) Additional boundary conditions result in smoother transitions at the end points between targeting maneuvers and increase the peak maneuver angle rate and rigid-body torgues by a larger percentage than do additional design parameters. Next, planar dynamics equations of motion for a uniform, inextensible, cantilevered beam capable of small transverse deformations and which retain the rotational (centrifugal) nonlinearities are derived via Newton's Laws, nondimensionalized and cast into a form suitable for numerical integration.

Descriptors :   *FLEXIBLE STRUCTURES, *SPACECRAFT, BOUNDARIES, COORDINATES, DEGREES OF FREEDOM, ANGLES, MANEUVERS, PEAK VALUES, RATES, DYNAMICS, EQUATIONS, PLANAR STRUCTURES, CANTILEVER BEAMS, CURVATURE, TRAJECTORIES, NUMERICAL INTEGRATION, PEAK VALUES, RIGIDITY, QUADRATIC EQUATIONS, THESES, CONTROL THEORY, NONLINEAR SYSTEMS, ROTATION, MANEUVERS, SLEWING, TRAJECTORIES, DEFORMATION, TRANSVERSE, PARAMETERS

Subject Categories : Unmanned Spacecraft
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE