Showing papers on "Proportional control published in 1985"

Quaternion feedback for spacecraft large angle maneuvers

Abstract: This paper presents the stability and control analysis for large angle feedback reorientation maneuvers using reaction jets. The strapdown inertial reference system provides spacecraft attitude changes in terms of quaternions. Reaction jets with pulse-width pulse-frequency modulation provide nearly proportional control torques. The use of quaternions as attitude errors for large angle feedback control is investigated. Closed-loop stability analysis for the three-axis maneuvers is performed using the Liapunov stability theorem. Unique characteristics of the quaternion feedback are discussed for single-axis motion using a phase-plane plot. The practical feasibility of a three-axis large angle feedback maneuver is demonstrated by digital simulations.

Control System Principles and Design

Abstract: Component Modeling Component Sizing for the Basic System Logic Controls System Performance Specifications Absolute Stability Criteria On-Off Control and Nonlinear System Analysis Proportional Control and Basic Feedback System-Design Procedures Integral Control Derivative Control Modes Combined and Approximate Control Modes Case Studies and Special Topics Digital and Computer Control Index.

A Microprocessor-Based Electrode Movement Controller for Spot Weld Quality Assurance

Abstract: Quality assurance has been of a great concern in the process of resistance spot welding, since considerable variation in the weld quality often arises even when the machine variables are held constant. In this paper a new microprocessor-based control method is developed to obtain uniform weld quality regardless of the changing welding environments. The control system utilizes a proportional (P) control algorithm, incorporating with the electrode movement as a feedback variable. The controller generates the welding control current so as to track a desired trace of the electrode movement (reference electrode movement curve) throughout weld cycle. A series of experiments was performed to evaluate the performance of this control method. The results show that, as a result of the electrode movement tracking, weld strengths of all the weldments approach to a desired strength level.

Stabilization of a High Voltage AC-DC Power System I. Evaluation of Control Strategies

Abstract: Various optimal and suboptimal stabilizing signals for a single machine infinite bus system connected through an ACDC link have been investigated. The controls in order of effectiveness of transient control are the linear state regulator control, a quasioptimal proportional control, output regulator controls from terminal voltage and frequency, and frequency and acceleration. From implementation viewpoint the proportional control is preferred. This scheme can also be easily extended to Include the nonlinearities in the system dynamics.

Process Control for a Rapid Optical Annealing System

Abstract: When high temperature processes are being carried out in a diffusion furnace, temperature control is accomplished in a straight forward manner. By using thermocouples and a proportional controller, sufficient accuracy and control are available to the process engineer. But with the current shift toward the more rapid annealing schemes, better control is a necessity. In order to achieve this accuracy, especially when the heat source is a 100 kilowatt arc lamp, more sophisticated control methods must be employed. By using an optical pyrometer tuned to operate at a wavelength where external interferences are minimized, wafer temperature may be monitored to a high degree of accuracy and with the fast response times needed. Coupling the output of the pyrometer to a microprocessor based controller allows the engineer to create and use multi stepped time/temperature profiles which are highly repeatable. This paper will describe such a system and how it is used in a production oriented rapid optical annealing system.

Control system for drive train including continuously variable transmission

Abstract: A control system for a motor vehicle drive train including a continuously variable transmission is disclosed wherein a command signal is generated in response to the sum of an integral control factor and a proportional control factor, and the integral control factor is suppressed to almost zero when a deviation of a reduction ratio representative parameter from a target value is greater than a predetermined value.

Ratio control system for continuously variable transmission

Abstract: A ratio control system for a continuously variable transmission performs a feedback control wherein an integral control gain and a proportional control gain are varied depending upon the level of a line pressure that is used to actuate a pulley unit during shifting operation.

Stabilization of a High Voltage ACDC Power System II. Multimachine System Subjected to Large Perturbation

Abstract: This article presents a stabilizing control strategy for a multimachine ACDC power system under large perturbation conditions. The controller is designed with local variables. The dynamics of the AC and DC systems are presented and a solution technique based on diakoptical methods is discussed. The response recorded for a multimachine system with a DC link shows that a sub-optimal proportional control of excitation voltage and firing angle of the converters provide an effective control of transients.

Control device for press load

Abstract: PURPOSE:To adjust air pressure with good accuracy and to permit easy control of press load by the constitution in which a proportional solenoid valve provided between a hydraulic blank holder and air source is electrically and automatically controlled by a control circuit in accordance with a set value. CONSTITUTION:A pressure reducing means, etc. consisting of the proportional control valve 1, check valve 2 and directional control valve 3 are provided to the air circuit of a press load control device constituted by connecting an air chamber 53 in the hydraulic blank holder to the air source 57 via the air circuit and connecting an oil chamber 52 to a hydraulic source 56 and an oil chamber 64 in a protector cylinder 63 which is the connecting part between a connection screw 61 and a slide 62. The valve 1 is controlled by a CPU8, D/A converter 9, controller 10, etc. in accordance with the set value from an input board 6 of the control circuit 5 to operate the valve 3 according to need thereby discharging the pressure in an air cylinder 59 through a relief valve 4 and regulating the pressure in the chamber 53.

Displaying device of quantity of combustion

Abstract: PURPOSE:To enable information concerning energy saving and set termperature to be displayed in a combustion control device by a method wherein an amount of electricity in a proportional control valve for controlling the quantity of combustion is applied as an input and is connected to the LED driving element for displaying a level meter for a plurality of LEDs at the output side. CONSTITUTION:A proportional control amplifier circuit 5 is operated in response to the temperature sensed by a temperature sensor 1 in such a way the temperature shows a value set by a temperature setting unit 2, an amount of electricity for a proportional control valve 9 is controlled so as to control an amount of combustion. An LED driving element 10 having input voltage of an amount of electricity of the proportional control valve 9 has the function of LED lighting switch with the input voltage level being equally divided in response to the number of LED elements 11a, 11b, 11c, 11d and 11e of the LED unit 11. Therefore, all the lamps can be lit up to the LED element 11e starting from only the lit LED element 11a in response to the amount of energization. Since the amount of energization of the proportional control valve 9 is proportional to the amount of combustion, the LED is lit in response to the amount of energization and the amount of combustion is displayed by a display in the level meter.

Gas proportional valve

Abstract: PURPOSE:To perform ideal proportional control by connecting a square circuit to the output side of an operational amplifier and urging a valve body to a valve port by means of a spring. CONSTITUTION:A square circuit for squaring an output in proportion is connected to the output side of an operational amplifier, and a valve body is provided with a spring for bringing the valve body into contact with a valve port when the current value of a coil is zero. Thus, the gas pressure supplied to a burner is controlled to increase or decrease in proportion to the square of a difference between a detected temperature and a reference value, and the temperature difference and the gas flow rate are controlled substantially in the relation of linear proportion. Furthermore, even if the current value is near zero, proportional characteristic can be improved to accomplish ideal proportional control.

Disturbance-Rejection Capabilities of Distillation Control Systems

Abstract: In the absence of disturbances, no control action is needed to keep products on specification Yet, disturbances are so common that control is always required, especially over high-purity products from distillation columns The cost of poor control, exacted either as low product recovery or as excessive energy consumption, can be related to the integrated error sustained by the composition control loops Integrated error is a function of the magnitude of the disturbance, the sensitivity of the system to it, and the settings of the feedback controller For a distillation column, the sensitivity factor changes as a function of the variable manipulated to control composition Furthermore, the process steady-state gain and, therefore, the composition controller's proportional band even changes with the choice of structure of the other loops applied to the column This paper lists the sensitivities of product compositions to disturbances in feed rate and composition and in heat input as a function of the choice of manipulated variable It also identifies process gains as indicated by relative-gain calculations The integrated error thus estimated is then verified by nonlinear dynamic simulation This procedure leads to the choice of the control system most capable of rejecting the type of disturbance anticipated for a given column

Controller for vibrational excavation of excavator

Abstract: PURPOSE:To raise the excavating performance of an excavator while keeping its good operability by a method in which pilot oil pressures to be supplied to a direction control valve are varied by signals according to the operating conditions of a control lever, and a vibration is given to the bucket. CONSTITUTION:When a control lever (not illustrated) is operated toward the extension side, an operation signal S1' is sent out of a signal setting circuit 43, and a proportional control valve 36 on the extension side is controlled to a given opening degree. A direction control valve 11 is then operated by a pilot oil pressure corresponding to the opening degree, and the amount of working oil to be supplied to a cylinder 10 is exactly controlled. By an addition signal S5 com posed of a vibration signal S4 corresponding to the operating position of the control lever and the operating signal S1', the cylinder 10 is vibrated by operating the proportional control valve 36 and the direction control valve 11 in order to intensify vibration to be applied to the bucket according to the excavating speeds. Even when the control lever is operated toward the contraction side, good operability is obtained as in the case of operation on the extension side, and the excavation performance can thus be sufficiently raised.

A proportional control experiment on air cushion heave stabilization

Abstract: Etude experimentale de la stabilisation verticale d'un coussin d'air par une commande proportionnelle

Positioner switching device of control valve

Abstract: PURPOSE:To prevent the generation of a disturbance in positioner switching and to perform invariably stable control by controlling transient valve behavior after the positioner of a control valve is switched to a backup mode at a preset speed according to the characteristics of a system. CONSTITUTION:A positioner switching part 77 is provided at the exit side of a tracking arithmetic part 14, and a positioner switching part 77' is also provided at the entrance side of an automatic control arithmetic part 18. When a tracking mode is switched to an automatic control mode, PI control is entered while a gain K is still equal to an optimum proportional gain Ks as far as the control valve is normal. If the control valve is abnormal, the K is decreased temporarily and then increased by a value (d) which determines the response speed in switching at every sampling time to suppress an output as much as possible. The control valve is controlled slowly during said period to suppress an abrupt change of the control valve, and normal control is entered a specific time later. Thus, the generation of a disturbance is prevented.

Design of Non-Linear, Time-Delay Control Systems: Application to Resilient Heat-Coupled Distillation Processes

Abstract: This paper reports the first application of decoupling theory to design a multivariable (MV) controller for a 3-input 3-output heat-integrated double-effect distillation process having multiple state and control delays. An extended MV Smith's compensator is theoretically established and subsequently employed to realize an effective feedback control system. This new MV time-delay compensator coupled with traditional proportional (P) controller is implemented on the non-linear distilling system possessing significant transportation lags in the recycle flows. A series of computer simulations reveal that the delay compensator dramatically improves the system responses and rejects feed disturbances. It is expected that even greater advantages over conventional P and PI controllers can be drawn in case of interconnected chemical process units where system delays, process disturbances and loop-interactions are considerably larger.

Stack type direction switching valve

Abstract: PURPOSE:To perform proportional control over the flow supplied into an actuator by controlling the pressure difference between an in-port and an out-port of a direction switching valve at a constant level within a range allowable for the prescribed set pressure. CONSTITUTION:A pressure balance type pressure control valve 7 is installed between a fluid pressure line 3a at the in-port side of a direction switching valve 1 and its return line (R) to maintain the pressure difference between the in-port and the out-port of the direction switching valve 1 at a constant level and a pressure control valve 8 is placed between a pilot pressure line (PL2) of the direction switching valve 1 and its return line (R) to set the maximum operational pressure, while a reducing valve 9 is installed between the fluid pressure line 3a and a pilot valve 15 to set the pilot pressure on the pilot valve 15. Accordingly, proportional control over the fluid flow supplied to the actuator in response to the end position of the direction switching valve 1 can be performed, thus enabling a program control.

Air-fuel ratio feedback control method for internal combustion engine

Abstract: PURPOSE: To carry out the air-fuel ratio control suitable for all kinds of cars by setting the proportional control portion and integration control portion in the air-fuel ratio feedback control to the different values according to the kind of the car, such as a car equipped with an automatic transmission and a car equipped with a manual transmission. CONSTITUTION: Into an electronic control unit 5, each detection value of a throttle valve opening degree sensor 4, absolute pressure sensor 8 in suction pipe, engine revolution angle position sensor 9, cylinder discriminating sensor 10, O 2 sensor 13, etc. is input. The electronic control unit 5 controls the valve opening time of a fuel injection valve 6 on the basis of the detection value of each sensor, and carries out the feedback control for air-fuel ratio. In case of a car equipped with an automatic transmission, each of proportional control portion and the integration control portion for the feedback control is set to the smaller value in comparison with that in case of a car equipped with a manual transmission, and generation of hunting, etc. is prevented. COPYRIGHT: (C)1987,JPO&Japio

Controller for vibro-excavation of excavator

Abstract: PURPOSE:To raise the excavating power of an excavator by a method in which an amplitude-level vibration signal corresponding to an integral signal value to be outputted in response to an excavation impossible detection signal is added to an operation signal, and according to the addition signal, a proportional control valve is driven. CONSTITUTION:When a control lever (not illustrated) is operated toward the extension side under a condition that a vibration input switch 45 is on, an operation signal S1' and an extension side signal are sent out from a signal setting circuit 43 and a direction judgement circuit 44, and according to the signal S1', a direction control valve 11 is driven through a proportional control valve 36 to keep a cylinder 10 at an extension-side excavation speed. When the excavation is made impossible, an integral signal S3 is sent out from an integral circuit 47 in response to signals T from a detector 46, and a vibration signal S4 to increase amplitude in response to the signal S3 as the impossibility of excavation continues is sent from a vibration signal generator 48 to an addition circuit 49 and added to the signal S1'. The proportional control valve 36 is driven by the addition signal S5, and the cylinder 10 is operated through the direction control valve 11 to vibrate a bucket (not illustrated) for excavation.

Feedback Control in Chamferless Assembly of Compliantly Supported Rigid Parts

Abstract: In this paper feedback control strategies for insertion of mating parts in automated assembly operations are presented. The question of maximum allowable misalignment before the initiation of assembly operation is studied and the effect of proportional (P), proportional plus integral (PI), and proportional plus integral plus derivative (PID) control actions on the assembly process is examined.

Stabilization of a highvoltage acdc power system ii.multimachinesystemsubjectedto large perturbation

Abstract: Thisarticle presents a stabilizing control strategy foramultimachine ACDC powersystemunderlarge perturbation conditions. Thecontroller isdesigned withlocal variables. The dynamicsoftheAC andDC systemsare presented and a solution technique basedon diakoptical methodsis discussed. The responserecordedfor a multimachine systemwith a DC linkshowsthata sub-optimal proportional control ofexcitation voltage and firing angleoftheconverters provide aneffective control of transients.

Automatic regulator of controlling motor speed

Abstract: PURPOSE:To eliminate the personal difference of shortening and regulating a regulating time by automatically calculating a proportional constant to automatically decide and regulate the gain of an amplifier. CONSTITUTION:When starting an automatic regulation, a current command converter 12 is first switched to become a command iM* from a current setter 11. Calculating means 20 calculates a proportional gain Kp to be set to a proportional amplifier 7 from a target responding time (tau), the first detecting speed set value omegar1, the second detecting speed set value omegar2, accelerating time tacc measured by time counting means 18, and the value iM*. Gain setting means 21 sets the proportional gain Kp of the amplifier 7 on the basis of the calculated result. After the setting is finished, the converter 12 is switched so that the output of a control amplifier 1 becomes the input of a power converter 8 to substantially disconnect a block added for an automatic regulation, and a normal speed feedback control is performed.

Gas burning proportional control device

Abstract: PURPOSE:To reduce extremely power consumption by a method wherein only switching is utilized for gas proportional control. CONSTITUTION:An electromagnetic coil 10 of a gas proportional control valve 7 is formed of two coils 101, 102 which are separated by a common terminal. Each switch element with control pole 121, 131 is provided at terminals which are located non-common terminal side of the electromagnetic coil 10. A direct current power source 11 is interposed between a terminal which is connected to the non-coil side terminal of the switch elements with control pole 121, 131 and the electromagnetic coil 10, then the switch elements 121, 131 are provided to be turned on alternatively by a drive circuit 18 which is connected to each control pole of the switch elements with control pole 121, 131. Thereby, the power consumption can be reduced extremely.

Controller for combustion

Abstract: PURPOSE:To contrive the improvement in safety by controlling a main power source to be supplied to a proportional solenoid valve against an overshoot phenomenon of more than a predetermined level, by providing an overshoot detecting circuit and a control device controlling the main power source of the proportional solenoid valve. CONSTITUTION:A temperature signal of supply hot water from a temperature- sensing element 5 and an overshoot detecting signal corresponding to an overshoot detecting temperature which is higher than a predetermined temperature by an arbitrary temperature are provided independently of a proportional control operation circuit 1. When the temperature of the supply hot water becomes higher than the predetermined temperature and overshoot is detected by an overshoot detecting circuit 6, an output of the same is inverted to ''H'' at a logical level and a control transistor 7 is made to turn OFF. With this construction, a main power source 4 to a proportional solenoid valve 3 is controlled independently of the proportional control operation circuit 1, combustion is controlled, the overshoot is controlled and safety can be improved.

Modeling Plant Non-Linearities for Instantaneous Optimal Control

Abstract: Frequently, one will find that the conditions for optimality in chemical production are determined by the non-linearities in the plant itself, while the economic objective function might be linear If the control variables do not enter the objective function, it is found that the instantaneous optimal conditions are found where the product of the sensitivity matrix of the state variables to the control and the gradient of the objective function in the state space is zero In some cases, this means that the process state is insensitive to the control at the optimum, which makes traditional proportional control instable Therefore, the modeling and parameter estimation for process non-linearities to identify an optimum become essential The control problem becomes a tracking problem This paper describes the application of those ideas to a simple continuous stirred tank reactor with multi-component and multi-reaction kinetics

Electromagnetic pump associated with pressure proportional controller

Abstract: PURPOSE:To control the delivery pressure of pump between the highest and lowest setting levels by providing an electromagnetic pressure proportional valve at the communicating section from the delivery side to the suction side then varying the power supply time to the control coil. CONSTITUTION:A flow path 44 coupled to the delivery flow path or to the interior of plunger case is provided. A relief valve 46 to be functioned with a spring 49 corresponding with the maximum pressure setting is provided in said flow path 44. It is coupled through said relief valve 46 and a communicating section 43 to the suction side 19. It is further coupled through flow paths 32, 34, 41 from the delivery side to the suction side 19. Electromagnetic pressure proportional control valves 30 are provided in said flow paths. A relief valve 36 to be functioned with a spring 39 corresponding with the minimum pressure setting is provided in the downstream of said valve 30. Pulses are fed to the control coil 25 of the proportional control valve 30 by varying the power supply time.

Time-Varying Smoothing for Proportional Navigation

Abstract: Variable smoothing in proportional navigation is implemented by modern homing guidance with time-varying state estimation followed by time-varying control. This system is examined by the techniques associated with classical homing guidance, normalized adjoints and idealized trajectory responses.

Speed controlling method in engine test device

Abstract: PURPOSE:To keep off high-speed responsiveness ever so favorable as well as to accelerate the built-up of engine speed, by controlling a solenoid proportional control valve installed interposingly in a discharge flow passage of a hydraulic pump, while maintaining the engine speed at the setting one. CONSTITUTION:A hydraulic pump 2 is interlockably coupled to a test engine 1 being in a state of firing operation. Then, a solenoid proportional control valve 13 is interposingly installed in a discharge flow passage 12 of the hydraulic pump 2. An engine speed and opening of the solenoid proportional control valve 13 both are stored in a random access memory of a controller 14 as a table. Afterward the engine speed reaches the setting one or after the elapse of the preset time, the solenoid proportional control valve 13 is controlled in feedback control and the engine speed is made to keep up with the setting one. The stored opening of the solenoid proportional control valve 13 is renewed to the actual opening at a time when it comes to the setting speed. Thus, high-speed responsiveness is maintainable ever so favorable.