Showing papers on "Proportional control published in 1976"

Digital controllers for VTOL aircraft

Abstract: Using linear-optimal estimation and control techniques, digitaladaptive daptive control laws have been designed for a tandem-rocopteror heliopter which is equipped for fully automatic flight in terminal area operations. Two distinct discrete-time control laws are designed to interface with velocity-command and attitude-command guidance logic, and each incorporates proportional-integral compensation for nonzero-set-point regulation, as well as reduced-order Kalman filters for sensor blending and noise rejection. Adaptation to flight condition is achieved with a novel gain-scheduling method based on correlation and regression analysis. The linear-optimal design approach is found to be a valuable tool in the development of practical multivariable control laws for vehicles which evidence significant coupling and insufficient natural stability.

Control of spinning flexible spacecraft by modal synthesis

Abstract: A procedure is presented for the active control of a spinning flexible spacecraft. Such a system exhibits gyroscopic effects. The design of the controller is based on modal decomposition of the gyroscopic system. This modal decoupling procedure leads to a control mechanism implemented in modular form, which represents a distinct computational advantage over the control of the coupled system. Design procedures are demonstrated for two types of control algorithms, linear and nonlinear. The first represents classical linear feedback approach, and the second represents an application of on-off control, both types made feasible by the modal decomposition scheme.

Optimal and Suboptimal Guidance for a Short-Range Homing Missile

Abstract: Optimal and suboptimal guidance laws for short-range homing missiles are developed and compared to the commonly mechanized quidance law of proportional navigation. The optimal controller is derived as an optimal feedback regulator; the suboptimal controller is an approximation of the optimal regulator and consists of timevarying proportional navigation plus a time-varying gain term times a calculated target acceleration. Monte Carlo studies of the three controllers show that the optimal and suboptimal controllers are much superior to proportional navigation for the case of combined constant target acceleration, line-of-sight rate noise, and missile acceleration saturation.

Optimal impulse control of a diffusion process with both fixed and proportional costs of control

Abstract: This paper concerns the optimal control of a system where the state is modeled by a homogeneous diffusion process in R1. Each time the system is controlled a fixed cost is incurred as well as a cost which is proportional to the magnitude of the control applied. In addition to the cost of control, there are holding or carrying costs incurred which are a function of the state of the system. Sufficient conditions are found to determine the optimal control for an infinite horizon problem. The optimal policy is one of "impulse" control originally introduced by Bensoussan and Lions [2] where the system is controlled only a finite number of times in any bounded time interval and the control requires an instantaneous finite change in the state variable. The issue of the existence of such controls is not addressed.

Model helicopter throttle governor/collective pitch control apparatus

Abstract: A throttle governor/collective pitch control apparatus for radio controlled model helicopters for proportionally controlling either the model helicopter rotor speed or the rotor collective pitch, including sensing and timing means determining the rotor speed and any changes thereof, comparison means for comparing a subsequently sensed rotor speed with a first sensed rotor speed and developing an error signal, and control means responsive to the error signal to provide a control signal proportional to any changes in the rotor speed. In the throttle governor mode any variations in rotor speed result in a proportional control signal to vary the model helicopter throttle so as to maintain constant rotor speed. In the auto-collective mode changes in rotor speed result in a proportional control signal coupled to the collective pitch servo for proportionally varying the model helicopter collective pitch.

Thermal control circuit

Abstract: PURPOSE: To devise to use the same electromagnetic proportional control valve and the same valve control circuit for different gases by changing the intensity of interrupting electricity according to the sort of gas to close perfectly the electromagnetic proportional control valve to control the combustion amount with the signal froma a thermal sensor element. COPYRIGHT: (C)1978,JPO&Japio

Proportional pulse controller

Abstract: An electrical actuator such as a direct current solenoid or motor is energized by a square wave voltage having an amplitude which applies full operating voltage to the actuator during each pulse. The duty cycle of the applied voltage is variable between predetermined minimum and maximum values, the minimum value being sufficiently high to overcome the starting hysteresis of the actuator. The control apparatus has particular application to proportional control systems, such as in the selective operation of dual solenoid, hydraulic control valves. A hand controller is provided with a handle having a center off position and on positions in opposite directions corresponding to the two solenoids. As the handle is moved away from the off position in either direction through an initial, relatively small displacement, a switch is actuated to apply the square wave voltage to the appropriate solenoid. Additional movement by the operator causes the duty cycle to vary from minimum to maximum as desired. The resistance of a phototransistor determines the value of the duty cycle, and is varied by a cam-shaped shutter operated by the controller handle and which is interposed between the phototransistor and a light-emitting diode. The hand controller may be electrically isolated from the actuators through the use of fiber optic light guides to transmit control information. A fail-safe circuit is provided by a missing pulse detector that deenergizes the controlled actuator if a component failure causes a constant driving voltage to be produced.

Speed Control of D. C. Motor Using Teyristor Dual Converter

Abstract: The paper describes the design, construction and testing of a closed-loop system for the speed control of a separately excited d.c. motor fed from a dual converter. The dual converter makes possible regenerative braking and reversal of direction of rotation. There is only one firing unit and the firing pulses are diverted to the appropriate converter by a master controller. There are three control loops: one for armature current control, one for adjusting the firing angle of the oncoming converter, and one for speed control.

Digital control laws for the space shuttle orbiter

Abstract: The purpose of this paper is to describe the Space Shuttle Orbiter manual command augmentation (CAS) control law. The paper addresses the configuration as presently baselined for the approach/land test (ALT) program. The requirements and problems associated with the ALT CAS control mode as well as the design/analysis approach used with it are representative of those associated with the operational atmospheric flight. The pertinent stability and performance requirements are summarized from the specifications. These considerations then lead to the selection of feedbacks, gains and filters where the last opens up the question of digital filter design. Special features of the resultant control laws include provision for command signal limiting (CSL) and the mechanization of the pitch axis proportional plus integral control. Digital filter design techniques used in obtaining bending filters differ from those used in obtaining lower frequency filters for rigid body control. These techniques and the rationale for their choice are summarized.

Master cylinder with proportional control valve

Abstract: PURPOSE:Master cylinder woth proportional control valve in which a braking force to be used for one of the front and rear wheels is proportional it decreased against the other braking force.