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Showing papers on "Proportional control published in 1987"


Journal ArticleDOI
TL;DR: A dynamic approach to the failure modeling of process control systems with control loops and continuous state dynamic variables such as pressure, temperature, and liquid level, based on the discrete state space-discrete time representation of PCS dynamics.
Abstract: Process control systems (PCS) are systems with control loops and continuous state dynamic variables such as pressure, temperature, and liquid level. Existing computer-assisted failure modeling schemes for PCS are based on a static description of system operation (eg, by digraphs, signal-flow-based graphs). This paper presents a dynamic approach to the failure modeling of PCS. The givens for the methodology are: 1) a set of first order differential equations with feedback describing the interaction between system variables, 2) failure and repair rates for the control units constituting the PCS. The methodology is based on the discrete state space-discrete time representation of PCS dynamics. Probabilistic system behavior is simulated by a Markov chain. An algorithm is developed for the mechanized construction of the transition matrix. Input preparation for the algorithm is illustrated by examples. Useful features of the methodology are: 1) failure model accuracy can be verified or improved by a change in the input data for mechanized model construction, 2) effect of changes in system parameters on PCS failure characteristics can be quantified. These features are demonstrated on a simple level-control system. The limitations of the methodology are discussed.

115 citations


Journal ArticleDOI
TL;DR: A multiple-model adaptive control procedure for sodium nitroprusside regulation of arterial pressure with Pole-placement, via state-variable feedback, included in the controller to achieve desired performance characteristics.
Abstract: This paper presents a multiple-model adaptive control procedure for sodium nitroprusside regulation of arterial pressure. Pole-placement, via state-variable feedback, is included in the controller to achieve desired performance characteristics. A Smith predictor in the controller effectively removes the infusion delay time, thus simplifying the control analysis and design. Proportional-plus-integral control is used to achieve zero steady-state error. Computer simulations on linear transfer function models with varying gains, time constants, and infusion delays demonstrate the robustness of this multiple-model controller. Additional simulations on nonlinear, pulsatile-flow cardiovascular models lend further support to the ultimate use of this controller for blood-pressure regulation.

105 citations


Patent
Yutaka Iino1, Takashi Shigemasa1
11 Aug 1987
TL;DR: In this article, an adaptive process control system comprises a controller of an I-P type generating a manipulating variable signal with a feed forward circuit responsive to the set point signal r(t), an integrator responsive to a difference between a process variable signal y(t) and set-point signal r (t), and an identification signal generator superposes a persistantly exciting identification signal h(t).
Abstract: An adaptive process control system comprises a controller of an I-P type generating a manipulating variable signal with a feed forward circuit responsive to the set-point signal r(t), an integrator responsive to a difference between a process variable signal y(t) and set-point signal r(t), and a feedback circuit responsive to the process variable signal y(t). An identification signal generator superposes a persistantly exciting identification signal h(t) to the control system. A frequency characteristic identifying circuit receives a discrete controlled data u(k) and y(k), estimates the parameters of the ARMA model by the least square method to identify the pulse transfer function, and obtains the transfer function in the continuous system as the frequency characteristics of gain and phase. A controller parameter calculating circuit calculates the controller parameters of the controller, such as integration gain K, proportional gain fo, and feed forward gain ff, using the frequency characteristics of gain and phase, and the overshoot, gain and phase margins, and attenuation ratio. The controller parameters are supplied via a switch to the controller.

73 citations


Journal ArticleDOI
TL;DR: It is shown that the I-P control scheme offers some distinctive advantages over P-I control, and experimental and simulation results are presented.
Abstract: A comparative study of proportional-integral (P-I) and integral-proportional (I-P) control schemes, for the speed control of a dc drive, using both analog-and microprocessor-based digital circuits, is presented. The often-neglected current response is discussed and results are presented. The speed response to step changes in speed reference and load torque, using both the control schemes, is compared to evaluate the merits of I-P control. A brief discussion of sensitivity to controller gains is also given. It is shown that the I-P control scheme offers some distinctive advantages over P-I control. Experimental and simulation results are also presented.

56 citations


Journal ArticleDOI
TL;DR: The feasibility of using multiple-model adaptive control to regulate arterial oxygen saturation and a comparison to a fixed, well-tuned proportional-integral controller showed an improvement in the regulatory response to a step disturbance.
Abstract: A computer-based proportional-integral (PI) controller has been developed to control arterial oxygen levels in mechanically ventilated animals. Arterial oxygen saturation is monitored using a noninvasive oximeter and control is effected by adjusting the inspired oxygen fraction. The performance of the feedback system is sensitive to the open-loop gain so that the desired transient specifications can be achieved only by empirical adjustments of the PI controller. Because the open-loop gain includes the animal's response, it may vary with time and with the administration of positive end-expiratory pressure. Multiple-model adaptive control procedures were therefore used to desensitize the system to these variable gains. Computer simulations demonstrated the effectiveness of the algorithm over a wide variation of plant parameters. A comparison to a fixed, well-tuned proportional-integral controller showed an improvement in the regulatory response to a step disturbance. Animal experiments confirmed the feasibility of using multiple-model adaptive control to regulate arterial oxygen saturation.

52 citations


Journal ArticleDOI
01 Apr 1987
TL;DR: In this article, a new methodology using the theory of variable structure systems is developed for accurate tracking control of robotic manipulators, based on a sliding mode controller, produces a discontinuity control input so that the nonlinear interactions and influence caused by unknown parameter variations can be depressed whereas the resulting control law is simple and easy to apply to on-line computer control.
Abstract: A new methodology using the theory of variable structure systems is developed for accurate tracking control of robotic manipulators. The proposed method, based on a sliding mode controller, produces a discontinuity control input so that the nonlinear interactions and influence caused by unknown parameter variations can be depressed whereas the resulting control law is simple and easy to apply to on-line computer control. The digital simulation results of a three-degree-of-freedom manipulator show the validity of accurate tracking capability and robust performance of the system with the developed control scheme.

30 citations


Journal ArticleDOI
TL;DR: In this paper, an effective straightforward method to design digital excitation and stabilizer controls for generating units is presented, which is feasible for implementation by simple software and therefore suitable for on-line computer control applications.
Abstract: An effective straightforward method to design digital excitation and stabilizer controls for generating units is presented. The excitation controller is designed in the S-domain with a proportional plus integral (PI) effect and then transformed to the Z-domain using a step invariance technique. The stabilizer is also designed in the S-domain by pole-zero placing techniques and mapped to the Z-domain to obtain the digital equivalent. Both controllers are feasible for implementation by simple software and therefore suitable for on-line computer control applications. Simulation study results on a laboratory size generator are presented to show the merits of the controllers obtained. The actual hardware design and implementation study results are presented in the companion part II of this paper.

29 citations


Patent
01 Sep 1987
TL;DR: In this article, a pilot valve is digitally controlled by pulses of constant frequency, while the duty factor determines the opening or closing times of the pilot valve, and the pulse duration is changed as a function of the operating temperature of the valve.
Abstract: A pilot valve is digitally controlled by pulses of constant frequency, while the duty factor determines the opening or closing times of the pilot valve. In addition, the pulse duration is changed as a function of the operating temperature of the valve, so that even very extreme fluctuations in the temperature of the valve are compensated and the proportional control behaviour of the pilot valve is improved considerably.

21 citations


Patent
15 Apr 1987
TL;DR: In this paper, an air/fuel ratio control system for an internal combustion engine is composed of a wide range oxygen sensor capable of sensing an actual air and fuel ratio from a rich side to a lean side, and a control unit having a reference determining section for determining a desired air/ fuel ratio in accordance with engine operating conditions such as engine speed and coolant temperature.
Abstract: An air/fuel ratio control system for an internal combustion engine is composed of a wide range oxygen sensor capable of sensing an actual air/fuel ratio from a rich side to a lean side, and a control unit having a reference determining section for determining a desired air/fuel ratio in accordance with engine operating conditions such as engine speed and coolant temperature, and a controlling section for controlling a fuel metering system such as fuel injectors so as to reduce a deviation of the actual air/fuel ratio from the desired air/fuel ratio in accordance with a prescribed control action such as a proportional plus integral control action. The control unit is further provided with a reference discriminating section for determining whether the desired air/fuel ratio is in a rich range or in a lean range, and a feedback control constant adjusting section for adjusting at least one control constant such as a proportional gain and an integral gain in dependence on the determination of the reference discriminating section to enable the controlling section to implement the optimum feedback control over the wide range.

15 citations


Proceedings ArticleDOI
Yilong Chen1
01 Mar 1987
TL;DR: A discrete time system model of a robot arm is derived and limitations of PD controllers are shown and a Lag-lead compensator is designed by a frequency-response analysis based on this model, along with the algorithm for realizing this compensator.
Abstract: The feedback algorithm widely employed in the various current control strategies is a digital implementation of a conventional proportional plus derivative (PD) control. For dynamic control of robots, this algorithm can be shown to lead to unsatisfactory trade-offs between static accuracy, system stability, insensitivity to model structure inaccuracies and high frequency noise rejection. These trade-offs become even more serious as sampling rate decreases. To reduce these trade-offs, a more realistic discrete time system model of a robot arm and a more sophisticated feedback compensator are required. In this paper, a discrete time system model of a robot arm is derived and limitations of PD controllers are shown. They are consistent with our simulation and experimental results. Also a Lag-lead compensator is designed by a frequency-response analysis based on this model, along with the algorithm for realizing this compensator. Simulations and tests are conducted, which show encouraging results in reducing the trade-offs.

15 citations


Patent
21 Jan 1987
TL;DR: In this article, a method of detecting abnormality in an air-fuel ratio control system for an internal combustion engine, the air fuel ratio controller system having a proportional control valve arranged in the air supply passage for supplying secondary air there through to the engine and controlled in response to an output signal from an oxygen concentration sensor arranged in an exhaust system of the engine in a manner such that its valve opening varies in proportion to the magnitude of driving current supplied thereto.
Abstract: A method of detecting abnormality in an air-fuel ratio control system for an internal combustion engine, the air-fuel ratio control system having a proportional control valve arranged in an air supply passage for supplying secondary air therethrough to the engine and controlled in response to an output signal from an oxygen concentration sensor arranged in an exhaust system of the engine in a manner such that its valve opening varies in proportion to the magnitude of driving current supplied thereto. A circuit is provided which includes a first transistor, the proportional control valve, and a second transistor arranged in the order mentioned and serially connected with each other between a power source for supplying a predetermined voltage and ground. A value of voltage at a predetermined location in said circuit is sensed while the first and second transistors are in predetermined states of conduction and non-conduction. It is determined whether there is abnormality in the air-fuel ratio control system, on the basis of the sensed voltage value.

Proceedings ArticleDOI
10 Jun 1987
TL;DR: In this article, a pseudo-derivative feedback is proposed to obtain the attendant benefits of derivative action, without taking the derivative of the error function, which overcomes many of the major problems of derivative control.
Abstract: The extensive presence of simple PID controllers all over the process and manufacturing industries attests to their continuing and lasting effectiveness in dealing with all but the most complex and demanding industrial control problem. Problems do arise with PID controllers however. In particular high frequency sensor noise problems can become severe in some applications, due to the presense of the D component of the PID controller. By altering the controller structure slightly, it is possible to obtain the attendant benefits of derivative action, without taking the derivative of the error function. This is called pseudo-derivative feedback and overcomes many of the major problems of derivative control. The structure and ramifications of this scheme is examined here, for both multivariable and single input single output systems.

Patent
28 Feb 1987
TL;DR: In this paper, a method to maintain the performance of hot-water supplier in spite of the deterioration with age of the gas supplying capacity of the proportional valve or the heat exchanging efficiency of heat exchanging section or the capacity of a proportional valve by a method wherein a correcting circuit, correcting the maximum opening degree and the minimum opening degree of the fuel proportional valve, is provided in the hotwater supplier.
Abstract: PURPOSE:To permit to maintain the performance of hot-water supplier in spite of the deterioration with age of heat exchanging efficiency of heat exchanging section or the capacity of a proportional valve by a method wherein a correcting circuit, correcting the maximum opening degree and the minimum opening degree of the fuel proportional valve by the amount of supplying hot-water obtained by a water amount sensor and entering water temperature as well as discharging hot-water temperature obtained by a temperature sensor during supplying hot-water, is provided in the hot-water supplier CONSTITUTION:An output operating circuit 13 outputs an actual hot-water supplying output (q) by (discharging hot-water temperature - entering water temperature) X amount of supplying hot-water An output limiting circuit 14 inputs a voltage, set by the output voltage of a proportional control circuit 11, the output (q) of the output operating circuit 13, a resistor 15, fixing the minimum output, and the resistor 16, fixing the maximum output, and outputs a proportional valve driving minimum voltage V1 and a proportional valve driving maximum voltage V2, inputted into a voltage limiting circuit 12 The voltage limiting circuit 12 limits the output of the proportional control circuit 11 so as to be V1 or higher and V2 or lower whereby a proportional valve driving voltage Ve is obtained According to this method, the maximum and minimum hot-water discharging outputs may be maintained so as to be the same as initial outputs in spite of the deterioration with age of the gas supplying capacity of the proportional valve or the heat exchanging efficiency of heat exchanging section

Proceedings ArticleDOI
10 Jun 1987
TL;DR: A microprocessor-based control system has been used to implement a control strategy that uses a mathematically simple algorithm together with the logic used by a skilled operator to achieve good control for setpoint changes and reactions in a multipurpose system.
Abstract: Achieving good temperature control in multipurpose, jacketed reactors is difficult Physical properties of the system change within a run and from run to run Setpoints are changed often, and nonreactive, exothermic, and endothermic processes must be controlled A microprocessor-based control system has been used to implement a control strategy that uses a mathematically simple algorithm together with the logic used by a skilled operator to achieve good control for setpoint changes and reactions in a multipurpose system

Proceedings ArticleDOI
10 Jun 1987
TL;DR: In this paper, an adaptive control algorithm, the self-tuning regulator (STR), was applied to control the injection phase of an injection molding machine cycle to control hydraulic pressure and cause it to follow a predetermined profile.
Abstract: An adaptive control algorithm, the self-tuning regulator (STR), was applied to control the injection phase of an injection molding machine cycle. The objective was to control the hydraulic pressure and cause it to follow a predetermined profile. The information of the previous cycle was used to correct the controller parameters for the next cycle. This computation is done between cycles. The STR control was found superior to standard proportional-integral control of the same system when high density polyethylene was injected into a heat distortion temperature test mold. Both algorithms had trouble controlling when acrylonitrile-butadiene-styrene was injected into a flex bar mold. A number of potential directions are proposed to improve the control for the latter conditions.

Patent
01 May 1987
TL;DR: In this paper, the same hot water control system is used to obtain an optimum hot water temperature characteristic by conducting the control of a gas proportional control valve setting automatically an optimum control characteristic based on a signal from a temperature sensor.
Abstract: PURPOSE:To make it possible to obtain an optimum characteristic by the same hot water control system even when the characteristic of a heat exchanger varies by conducting the control of a gas proportional control valve setting automatically an optimum control characteristic based on a signal from a temperature sensor. CONSTITUTION:At first, a general proportional differential/integral constant is stored in a memory part 12, and the control of the hot water is carried out as the memory characteristic at the initial part of the action. When the result of the action returns to a temperature sensor 9, a characteristic discriminating part 10 discriminates to what extent a deviation is produced with respect to the characteristic which is the object of a characteristic discriminating part 10. The result of the discrimination is delivered to an operating part 11 to carry out a correcting arithmetic operation. The result of the arithmetic operation is transmitted to a proportional valve drive circuit 13 and the memory in a memory part 12 is rewritten. Furthermore, the result is detected by the temperature sensor 9, the correcting arithmetic operation is repeated to make up an optimum characteristic. As described above, it is possible to obtain an optimum hot water temperature characteristic without selecting optimum constants individually in accordance with the characteristic of the heat exchanger.


Patent
27 Jul 1987
TL;DR: In this paper, a proportional control valve is employed for controlling a secondary air quantity to an engine, by utilizing the voltage value in a connecting point of said control valve to a transistor in a driving circuit.
Abstract: PURPOSE:To make it possible to accurately detect failures in an earth side portion, in the case of an air-fuel ratio control device employing a proportional control valve for controlling a secondary air quantity to an engine, by utilizing the voltage value in a connecting point of said control valve to a transistor in a driving circuit. CONSTITUTION:An air-fuel control device controls an air-fuel ratio to the predetermined value by changing, in an ECU 20, the duty of a solenoid valve 9, in a secondary air supply passage provided with a throttle valve on the alternate route thereof, in response to the output of an O2 sensor. In this way, between a power source in the ECU 20 and an earth, the first transistor Tr 1 of a failure detecting drive circuit 28a, solenoid 9a of a solenoid valve 9, second transistor Tr 2 of a solenoid valve controlling drive circuit 28b and a resistance R connected to each other in series. And, the connecting point A of the solenoid valve 9 to Tr 2 is connected to the failure detecting signal input terminal 29c of CPU 29, thereby at the time when the voltage value of the connecting point A, in the case that current is applied to Tr 1 and the current is not applied to Tr 2, is under the predetermined value, it is judged by the solenoid valve 9 that failures are generated at the earth side portion.

Journal ArticleDOI
TL;DR: In this paper, an optimal proportional-plus-integral control is employed to eliminate steady-state error which is sustained by a simple proportional control for tracking a circular path, and a simple and readily-implemented suboptimal control is also examined.
Abstract: An optimal control procedure is presented for steering an Auto-Guided- Vehicle (AGV) which has two motored wheels on its left and right side. Steering, running and stopping are enabled by controlling the motor speed independently.An optimal proportional-plus-integral control is employed to eliminate steady-state error which is sustained by a simple proportional control for tracking a circular path. A simple and readily-implemented suboptimal control is also examined. The suboptimal control gives comparable performance and therefore provides an effective approach for industrial application of the AGV.Effects of design parameters of the AGV such as forward velocity, wheel radius and position of sensor are investigated. It is shown that within the practicable values the controlled performance improves rapidly but with an increase of those parameters then the improvement becomes negligible, which suggests base values for the parameters.

Patent
12 Mar 1987
TL;DR: In this paper, a feedback control system for controlling the velocity or position of a member 12 uses two control loops which are interlinked by lines 20,21 and also by a control line 16 which responds to the force applied to an input member 10, the resulting system thus giving a sense of feel via a motor 36 to the input member, without using a force transducer at the output member.
Abstract: A feedback control system for controlling the velocity or (as shown) position of a member 12 uses two control loops which are interlinked by lines 20,21 and also by a control line 16 which responds to the force applied to an input member 10, the resulting system thus giving a sense of feel via a motor 36 to the input member 10 without using a force transducer at the output member. The input demand signal on line 20 is directly proportional to the output position or output velocity. Similarly, the output demand signal on line 21, or the derivative of the output demand signal for velocity control, is directly proportional to the position of the input. Velocity feedback loops 34,39 may be provided. Desirably the output position controller (29) operates under proportional control, and the input position controller operates under PID control. The system may be used to control a robot hand e.g. in nuclear, deep sea or other hostile environments, or a wheelchair.

Journal ArticleDOI
TL;DR: A pneumatic servo-system composed of a cylinder installed vertically, double electro-pneumatic proportional control valves and feedback equipments has been developed for a Z axis actuator of a robot for assembly as mentioned in this paper.
Abstract: A pneumatic servo-system which is composed of a cylinder installed vertically, double electro-pneumatic proportional control valves and feedback equipments has been developed for a Z axis actuator of a robot for assembly. Optimal control method is applied to the system in order to accomplish accurate positioning and force control of the cylinder. Optimal control inputs for piston position and force have been computed by a microcomputer using optimal feedback coefficients which are derived from Riccati's equations so as to minimize settling time and overshoot of the step response in positioning and force control of the piston. In the piston control, the positioning repeatability of ±0.5 mm for the optimal control and ±0.2 mm for the optimal control with an integral compensator is achieved. On the other hand, the repeatability of within ±1% of an assigned force is obtained in the force control.

Proceedings ArticleDOI
10 Jun 1987
TL;DR: In this article, a control design procedure for linear time invariant systems using output proportional plus derivative feedback is presented, which has been applied to obtain an improved autopilot for the lateral dynamics of an L1011 aircraft.
Abstract: This paper presents a control design procedure for linear time invariant systems using output proportional plus derivative feedback. The traditional linear quadratic performance index is used with additional terms to penalize disturbance and noise response and eigenvalue and response sensitivities. The sensitivity terms represent measures of stability robustness. It is shown that the derivative feedback improves the measure of performance. This design procedure has been applied to obtain an improved autopilot for the lateral dynamics of an L1011 aircraft.

Patent
29 Oct 1987
TL;DR: In this paper, a proportional control valve control system for electrohydraulic proportional control is described, which includes a valve member, a valve drive, and a position sensing signal for providing an electrical position signal indicative of the valve member position.
Abstract: A control system for use with electrohydraulic proportional control valve means includes: - a valve member; - drive means to control the position of the valve member; and - position sensing means for providing an electrical position signal indicative of the valve member position. The control system further comprises input means for receiving the position signal, output means for supplying the drive signal, modelling means for determining a model signal indicative of the instantaneous flow rate and/or pressure drop across the valve means in dependence on the position signal and the drive signal, and comparison means for comparing the model signal with a demand signal indicative of a demanded flow rate and/or pressure drop across the valve means and for supplying an output signal to the output means in dependence on the result of the comparison.

Patent
01 Jul 1987
TL;DR: In this article, a proportional plus integral adjuster is used to suppress the transient voltage fluctuation to the minimum by providing a proportional-plus-integral control means to the loop to which a proportional control means is already provided so as to compare the voltage outputted by the inverter unit as it is in the sinusoidal wave with the reference sinusoid wave.
Abstract: PURPOSE:To suppress the transient voltage fluctuation to the minimum by providing a proportional-plus-integral control means to the loop to which a proportional control means is already provided so as to compare the voltage outputted by the inverter unit as it is in the sinusoidal wave with the reference sinusoidal wave and to control it. CONSTITUTION:The AC voltage outputted by an inverter unit composed of a transistor inverter 3 and a filter 4 is detected by a voltage transformer 11, rectified and smoothed by a rectifier 12 and a smoothing circuit 13 and the deviation from the voltage set out by a voltage setting device 14 is outputted to a proportional integral adjuster 15. A reference sinusoidal wave generation circuit 21 outputs a sinusoidal wave voltage of the same frequency as in the output of the inverter unit with the amplitude proportional to the output of the proportional integral adjustor 15. This output is compared with the sinusoidal wave voltage from the inverter unit and is outputted to a proportional adjuster 22. A transistor 3 is controlled by the output of said proportional adjuster 22 through a pulse duration modulation circuit 18 and a control circuit 19.

Patent
James I. Bartels1
15 Dec 1987
TL;DR: An automatic firing rate controller (55) uses proportional control squared, an integration which reflects the past load history to determine the present load, and further has a function term which relates the rate of change of pressure with respect to time in order to make more responsive the normal load control operation as discussed by the authors.
Abstract: An automatic firing rate controller (55) uses proportional control squared, an integration which reflects the past load history to determine the present load, and further has a function term which relates the rate of change of pressure with respect to time in order to make more responsive the normal load control operation. The system is also capable of on-off control that will hold the system in low fire to allow for stabilization, and to avoid thermal shock to a boiler (Fig. 3).

Patent
30 May 1987
TL;DR: In this paper, the authors proposed to improve the followability of the control by obtaining a target control signal value from a difference between a detection temperature and a set temperature and making the maximum change width within a predetermined period of time variable by the quantity of combustion.
Abstract: PURPOSE:To improve the followability of the control by obtaining a target control signal value from a difference between a detection temperature and a set temperature and making the maximum change width within a predetermined period of time variable by the quantity of combustion CONSTITUTION:A voltage from a temperature detection circuit 1 is subjected to a proportional control P, a differentiation control D, and two-step differentiation control D by means of a first control circuit 6, and a control voltage is output Further, a second control circuit 7 outputs an integration control signal I, and is reversed by an arithmetic amplifier 8 and fed back to an output point A of the first control circuit 6 via the normal direction of a diode 11 The output of the second control circuit 7 is fed back to the output point A of the first control circuit 6 via the reverse direction of a diode 12 By this construction, the maximum variation width of the control signal value is varied on the basis of the quantity of combustion, and the quantity of combustion can be varied in the maximum width where no poor combustion is produced, thus improving the followability of the control

Patent
19 May 1987
TL;DR: In this paper, the control responsiveness of a feedback control is improved by calculating a correct proportional gain from a variation of a deviation quantity and a manipulated variable at every sampling period, and varying dynamically the proportional gain.
Abstract: PURPOSE:To improve the control responsiveness of a feedback control by calculating a correct proportional gain from a variation of a deviation quantity and a manipulated variable at every sampling period, and varying dynamically the proportional gain CONSTITUTION:From a difference between a deviation e(t-tau) and e(t), and a difference of a manipulated variable v(t-tau) and v(t) at the time of the previous sampling and at the time of the present sampling, a proportional gain calculating means 4 calculates a new proportional gain (k) from a proportional gain k' at the time of the previous sampling by a prescribed operation and sets it to a manipulated variable calculating means 3 By executing repeatedly this operation at every sampling prdiod, an optimum proportional gain is always set, and a good control response having no overshoot nor hunting is obtained

Patent
02 Mar 1987
TL;DR: In this paper, a method to reduce the enlargement of the distortion of an output voltage by a method wherein a reference voltage generator, obtaining the input control signal of an element ON/OFF circuit for controlling a power converter, is considered virtually while an estimating current with respect to a load current and the first differential of the load current is utilized as a feedback signal for a control circuit is considered.
Abstract: PURPOSE:To reduce the enlargement of the distortion of an output voltage by a method wherein a reference voltage generator, obtaining the input control signal of an element ON/OFF circuit for controlling a power converter, is considered virtually while an estimating current with respect to a load current and the first differential of the load current is utilized as a feedback signal for a control circuit CONSTITUTION:A load 13, such as a power converter or the like, is connected to a single phase inverter circuit 11 through a LC filter circuit 12 An element ON/OFF circuit 14 puts ON/OFF the semiconductor switching element of the single phase inverter 11 A difference (e) between a reference objective value from a reference voltage generator 21 and an output from an operating circuit 15 is inputted into a proportional integration controller 10 Further, a difference between the first differential of the reference objective value and the amplified value of an input current outputted from the operating circuit 15 is inputted into a proportional control circuit 17 Then, the output of the proportional integration controller 16, the output of the proportional control circuit 17, the output of a multiplier 18 and a capacitor voltage Vc are added in an adder 19

Patent
26 Jan 1987
TL;DR: In this article, a range of reference values for selecting the burner or calorific value control method between a case where the required thermal load is increased and a case such as such is decreased is presented.
Abstract: PURPOSE:To prevent degradation of temperature characteristics at the time of transfer of working burner or changing of calorific value control method by allowing a range in which different reference values for selecting the burner or calorific value control method between a case where the required thermal load is increased and a case where such is decreased. CONSTITUTION:A selecting means 14 outputs necessary signals to first and second solenoid valves 10, 11 and first and second proportional control valve 12, 13 in accordance with the required thermal load F1 which is computed by an operating means 9. In this instance, the reference value for switching from the intermittent burn control to the proportional control for the second burner 3 is 2.5 when the intermittent burn control is transferred to the proportional control, and 1.6 when the proportional control is transferred to the intermittent burn control. As a range of reference value is given in this manner in that the reference value for the decreasing thermal load is made slightly smaller than the value for the increasing thermal load, there will not be frequent transfer between burners or control methods even if there is a fluctuation of required thermal load.