The IAC program provides the framework required for the development of an extensive multidisciplinary analysis capability. Several NASTRAN related capabilities were developed which can all be expanded in a routine manner to meet in-house unique needs. Plans are to complete the work discussed herein and to provide it to the engineering community through COSMIC. Release is to be after the current IAC Level 2 contract work on the IAC executive system is completed and meshed with the interfacing...
Topics: NASA Technical Reports Server (NTRS), DATA BASES, INTERFACES, MODULARITY, NASTRAN, DATA PROCESSING,...
The design and evaluation of a feedback control system via frequency response methods relies heavily upon numerical methods. In application, one can usually develop low order simulation models which for the most part are devoid of numerical problems. However, when complex feedback interactions, for example, between instrument control systems and their flexible mounting structure, must be evaluated, simulation models become moderate to large order and numerical problems become common. A large...
Topics: NASA Technical Reports Server (NTRS), DYNAMIC RESPONSE, ERROR ANALYSIS, FEEDBACK CONTROL, NUMERICAL...
Additions made to the original version of the DISCOS computer programs are presented. They include demonstrations of problems and improved capabilities. Remarks are made pertaining new subroutines.
Topics: NASA Technical Reports Server (NTRS), AUTOMATIC CONTROL, COMPUTER SYSTEMS PROGRAMS, COMPUTERIZED...
Specification of the mathematical equations required to define the dynamic response of a linear continuous plant, subject to sampled data control, is complicated by the fact that the digital components of the control system cannot be modeled via linear ordinary differential equations. This complication can be overcome by introducing two new mathematical operations; namely, the operation of zero order hold and digial delay. It is shown that by direct utilization of these operations, a set of...
Topics: NASA Technical Reports Server (NTRS), DYNAMIC RESPONSE, FREQUENCY ANALYZERS, NUMERICAL ANALYSIS,...
An algorithm was developed which can be used to obtain the equations. In a more general context, the algorithm computes a real nonsingular similarity transformation matrix which reduces a real nonsymmetric matrix to block diagonal form, each block of which is a real quasi upper triangular matrix. The algorithm works with both defective and derogatory matrices and when and if it fails, the resultant output can be used as a guide for the reformulation of the mathematical equations that lead up to...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, FEEDBACK CONTROL, FREQUENCY ANALYZERS, NUMERICAL...
The equations of motion for a system of coupled flexible bodies, rigid bodies, point masses, and symmetric wheels were derived. The equations were cast into a partitioned matrix form in which certain partitions became nontrivial when the effects of flexibility were treated. The equations are shown to contract to the coupled rigid body equations or expand to the coupled flexible body equations all within the same basic framework. Furthermore, the coefficient matrix always has the computationally...
Topics: NASA Technical Reports Server (NTRS), EQUATIONS OF MOTION, FLEXIBLE BODIES, SPACECRAFT...
The equations of motion are derived, in vector-dyadic format, for a topological tree of coupled rigid bodies, point masses, and symmetrical momentum wheels. These equations were programmed, and form the basis for the general-purpose digital computer program N-BOD. A complete derivation of the equations of motion is included along with a description of the methods used for kinematics, constraint elimination, and for the inclusion of nongyroscope forces and torques acting external or internal to...
Topics: NASA Technical Reports Server (NTRS), EQUATIONS OF MOTION, RIGID STRUCTURES, VECTOR ANALYSIS,...
For abstract, see N78-25123.
Topics: NASA Technical Reports Server (NTRS), ATTITUDE CONTROL, COMPUTERIZED SIMULATION, SPACECRAFT...
A theoretical development and associated digital computer program system for the dynamic simulation and stability analysis of passive and actively controlled spacecraft are presented. The dynamic system (spacecraft) is modeled as an assembly of rigid and/or flexible bodies not necessarily in a topological tree configuration. The computer program system is used to investigate total system dynamic characteristics, including interaction effects between rigid and/or flexible bodies, control...
Topics: NASA Technical Reports Server (NTRS), ATTITUDE CONTROL, COMPUTERIZED SIMULATION, SPACECRAFT...
A general purpose digital computer program was developed and designed to aid in the analysis of spacecraft attitude dynamics. The program provides the analyst with the capability of automatically deriving and numerically solving the equations of motion of any system that can be modeled as a topological tree of coupled rigid bodies, flexible bodies, point masses, and symmetrical momentum wheels. Two modes of output are available. The composite system equations of motion may be outputted on a...
Topics: NASA Technical Reports Server (NTRS), ATTITUDE CONTROL, COMPUTER SYSTEMS PROGRAMS, DIGITAL...
The development of an analysis software system capable of performing interdisciplinary preliminary design analyses of large space structure configurations is discussed. Disciplines such as thermal, structures, and controls are to be integrated into a highly user oriented analysis capability. The key feature of the integrated analysis capability, a rapid and efficient system that will minimize solution turnaround time, is discussed.
Topics: NASA Technical Reports Server (NTRS), COMPUTER SYSTEMS DESIGN, COMPUTER SYSTEMS PROGRAMS, DESIGN...
The MultiOptimal Differential Equation Language (MODEL) is described. It provides a means for generating numerical solutions to systems of differential equations using a digital computer. The notation of this language is similar to that usually used in describing physical systems by differential equations. Thus, the learning process is simplified, programming becomes easier, and debugging is more readily accomplished. Programs written in the MultiOptimal Differential Equation Language are...
Topics: NASA Technical Reports Server (NTRS), COMPUTERIZED SIMULATION, CONTROL SIMULATION, DYNAMIC CONTROL,...
The analytical simulation of deployment dynamics of these two axis concepts as well as the evolution of practical designs for the add on deployable inertia boom units is described. With the boom free to swing back in response to Coriolis forces as well as outwards in response to centrifugal forces, the kinematics of motion are complex but admit the possibility of absorbing deployment energy in frictional or other damping devices about the radial axis, where large amplitude motions can occur and...
Topics: NASA Technical Reports Server (NTRS), BOOMS (EQUIPMENT), COMPUTER AIDED DESIGN, COMPUTERIZED...
The technology developed for operator-in-the-loop simulation in space teleoperation has been applied to Caterpillar's backhoe, wheel loader, and off-highway truck. On an SGI workstation, the simulation integrates computer modeling of kinematics and dynamics, real-time computational and visualization, and an interface with the operator through the operator's console. The console is interfaced with the workstation through an IBM-PC in which the operator's commands were digitized and sent through...
Topics: NASA Technical Reports Server (NTRS), COMPUTERIZED SIMULATION, MAN MACHINE SYSTEMS, MANIPULATORS,...
