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Results for “SERVOMECHANISM”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

An approach to the linear multivariable servomechanism problem.

This paper presents a state-space approach to the multivariable 'type one' servomechanism problem. Necessary and sufficient conditions for the controllability of such systems are derived and applied to the observability of the (dual) state reconstructor problem for a system with an unknown constant input. The paper also presents a simple systematic design algorithm which provides type one servomechanism performance to command inputs, together with pre-specified closed-loop pole locations. Examples are given to illustrate the utility of the design procedure.

Young, P. C.↗
NASA NTRS1973

Servomechanism design techniques and applications aerospace problems

A cryogenic oxygen flow control servomechanism subsystem is described that is typical for an auxiliary power unit fuel system. Three possible types of feedback for this type of subsystem are: position with velocity feedback accomplished by gear train and synchro-transformer, position with velocity feedback accomplished by adding a rate generator and position feedback with compensating network. Servomechanisms employing any of these three types of subsystems can provide the oxygen flow control desired. The differences in performance relate primarily to steadiness of flow with the companion heat modulation. The damping ratio parameter can be used to achieve a reasonable response time.

Lalli, V. R.↗
NASA NTRS1973

Servomechanism design techniques and applications - Aerospace problems.

Transistorized alternating-current servomechanisms for a basic position servo with rate feedback or network compensation are reviewed. Studies of optimum methods of control position variables in aerospace applications show that no single method is best for all cases. The optimum method is very much dependent upon available devices, generating sources, and load parameters. These are constraints difficult to identify for future aerospace missions. Design and application considerations are discussed, along with step-by-step design procedures. For illustration, specific design problems are used to exemplify the approach to solutions.

Lalli, V. R.↗
NASA NTRS1978

Pneumatic servomechanisms

Dynamic analysis computer program analyzes pneumatic servomechanism and the system it controls. System and device to be modeled can contain up to twenty ullage chambers, twenty moving parts, and forty flow lines. Program is easily modified to model larger systems.

Bailey, T. E.↗
NASA NTRS1979

Robust decoupled servomechanism theory for linear multivariable systems

Decoupling theory and robust servomechanism theory are applied to the design of linear multivariable systems with large parameter variations. In addition to being approximately decoupled in the transient period, the over-all system achieves tracking and disturbance rejection robustly in the steady state.

Wang, S.-H.↗
NASA NTRS1979

Design of flight control systems via robust decoupled servomechanism theory

Decoupling theory and robust servomechanism theory are applied to the design of linear multivariable systems with large parameter variations. In addition to being approximately decoupled in the transient period, the over-all system achieves tracking and disturbance rejection robustly in the steady state. An example in flight control system is given.

Wang, S.-H.↗
NASA NTRS1981

Penetrating transmission zeros in the design of robust servomechanism systems

In the design of a robust servomechanism system, it is well known that the system cannot track a reference signal whose frequency coincides with the transmission zeros of the system. This paper proposes a new design method for overcoming this difficulty. The controller to be used employs a sampler and holding device with exponential decay. It is shown that the transmission zeros of the discretized system can be shifted by changing the rate of the exponential decay of the holding device. Thus, it is possible to design a robust controller for the discretized system to track any reference signal of given frequency, even if the given frequency coincides with the transmission zeros of the original continuous-time system.

Wang, S. H.↗
NASA NTRS1988

Angular-Momentum-Compensating Servomechanism

Servomechanism for rotating an instrumentation platform isolates supporting vehicle or stationary platform from reaction torques producedby rotations. Prevents aiming of instrument from disturbing vehicle or other instrument platforms. Rotating oppositely to instrument platform, reaction wheel, motor, and gear 1 have angular momentum equal and opposite to gear 2, output shaft, and platform. External torque reaction to rotation of platform canceled. Although spur gears appear in schematic diagram, gear train made of spline gears.

Marchetto, Carl A.↗
NASA NTRS1987

Adaptive proximate time optimal servomechanisms: Discrete time case

Following a review of the continuous time proximate time-optimal servomechanism (PTOS), a discrete-time PTOS is developed, along with conditions for its stability. An algorithm is proposed for adapting PTOS when the plant parameters are not known yielding APTOS (adaptive PTOS). Under ideal conditions APTOs is shown to be uniformly asymptotically stable. Simulation results demonstrate the predicted performance, and experimental results validate the practically of APTOS.

Workman, M. L.↗
NASA NTRS2001

Two Reconfigurable Flight-Control Design Methods: Robust Servomechanism and Control Allocation

Two methods for control system reconfiguration have been investigated. The first method is a robust servomechanism control approach (optimal tracking problem) that is a generalization of the classical proportional-plus-integral control to multiple input-multiple output systems. The second method is a control-allocation approach based on a quadratic programming formulation. A globally convergent fixed-point iteration algorithm has been developed to make onboard implementation of this method feasible. These methods have been applied to reconfigurable entry flight control design for the X-33 vehicle. Examples presented demonstrate simultaneous tracking of angle-of-attack and roll angle commands during failures of the fight body flap actuator. Although simulations demonstrate success of the first method in most cases, the control-allocation method appears to provide uniformly better performance in all cases.

Burken, John J.↗