Showing papers on "Proportional control published in 1990"
TL;DR: In this article, a new control strategy for on-off valve controlled pneumatic actuators and robots with focus on the position accuracy has been proposed, where one valve is held open and the other is operated under the pulse width modulation mode to simulate the proportional control.
Abstract: We propose a new control strategy for on-off valve controlled pneumatic actuators and robots with focus on the position accuracy. A mathematical model incorporating pneumatic process nonlinearities and nonlinear mechanical friction has been developed to characterize the actuator dynamics; this model with a few simplifications is then used to design the controller. In our control scheme, one valve is held open and the other is operated under the pulse width modulation mode to simulate the proportional control. An inner loop utilizing proportional-plus-integral control is formed to control the actuator pressure, and an outer loop with displacement and velocity feedbacks is used to control the load displacement. Also, a two staged feedforward force is implemented to reduce the steady state error due to the nonlinear mechanical friction. Experimental results on a single degree of freedom pneumatic robot indicate that the proposed control system is better than the conventional on-off control strategy as it is effective in achieving the desired position accuracy without using any mechanical stops in the actuator.
79 citations
13 May 1990
TL;DR: Three forms of robust model-based control were experimentally evaluated for controllers with good high-speed tracking accuracy in uncertain payload environments and all three techniques improved the tracking performance of the manipulator.
Abstract: Three forms of robust model-based control were experimentally evaluated. Algorithm evaluation was prompted by a requirement for controllers with good high-speed tracking accuracy in uncertain payload environments. The test case was a PUMA-560 operating over the standard test suite. The tracking performance of the robust algorithms was compared, with and without payload, to that of a nonadaptive model-based controller with fixed proportional-derivative (PD) feedback. The model-based controllers were made robust by the addition of an auxiliary input term, replacing the PD feedback with a feedback loop based on quantitative feedback theory (QFT), or an adaptive feedforward compensator based on Lyapunov theory. Experimental evaluation provided valuable insight into the potential and limitations of each method. All three techniques improved the tracking performance of the manipulator. Superior overall performance, computational simplicity, and a mathematically rigorous design and tuning procedure make the model-based controller with QFT feedback the algorithm of choice. >
40 citations
TL;DR: A graphical approach to hydrogenerator governor tuning is described in this article, where a graph which is developed can be used to predict optimum proportional and integral gains based on four parameters: the time constants of the water column and of the rotor inertia, and the self-regulation constants of turbine and the loading grid.
Abstract: A graphical approach to hydrogenerator governor tuning is described. A graph which is developed can be used to predict optimum proportional and integral gains based on four parameters: the time constants of the water column and of the rotor inertia, and the self-regulation constants of the turbine and of the loading grid. The pole cancellation method of design is used, and the results are posed in an easy-to-use format that does not require the solution of systems of equations. Information on stability limits and comparisons with other work are included. >
33 citations
TL;DR: In this article, an optimal suspension system for a quarter-car model using multivariable integral control is derived for a quadratic model using linear full-state feedback control laws with and without integral control together with the performance of passive suspensions.
Abstract: SUMMARY In this paper, an optimal suspension system is derived for a quarter-car model using multivariable integral control. The suspension system features two parts. The first part is an integral control acting on suspension deflection to ensure zero steady-sate offset due to body and maneuvering forces as well as road inputs. The second is a proportional control operating on the vehicle system states for vibration control and performance improvement. The optimal ride performance of the active suspensions based on linear full-state feedback control laws with and without integral control together with the performance of passive suspensions are compared.
27 citations
Patent•
20 Mar 1990
TL;DR: In this paper, a device for temperature control with high security and stability comprising means for heating and cooling are controlled by separate control circuits to make PROPORTIONAL control, INTEGRATED control, control DERIVATIVE and SIMILAR THROUGH WHICH RATE PERIODS of SUPPLY eNERGY is CHANGED to perIODs of DEFAULT control on the basis of VARIABLE CONTROLLED FROM address, size, rate of change and the like of temperature deviation.
Abstract: A DEVICE FOR TEMPERATURE CONTROL WITH HIGH SECURITY AND STABILITY comprising means for heating and cooling are controlled by separate control circuits TO MAKE PROPORTIONAL CONTROL, INTEGRATED CONTROL, CONTROL DERIVATIVE AND SIMILAR THROUGH WHICH RATE PERIODS OF SUPPLY eNERGY IS CHANGED TO PERIODS OF DEFAULT CONTROL ON THE BASIS OF VARIABLE CONTROLLED FROM address, size, rate of change and the like of temperature deviation NORMAL MEANS CONTROLLED TEMPERATURE SET DESIRED TO MANAGE SUPPLIES ENERGY AND COOLING WARMING MEDIA heating and cooling. ENERGY SUPPLIES AND COOLING WARMING MEDIA heating and cooling can be controlled separately by different proportional bands.
19 citations
05 Dec 1990
TL;DR: In this article, the problem of designing a composite control as a strategy for controlling flexible link manipulators is addressed, which consists of a slew control based on the reduced order model to achieve the desired slewing of the robot links and a fast control based upon a manifold condition whose purpose is to dampen the link vibrations.
Abstract: The problem of designing a composite control as a strategy for controlling flexible link manipulators is addressed. The composite control consists of a slew control based on the reduced order model to achieve the desired slewing of the robot links and a fast control based on a manifold condition whose purpose is to dampen the link vibrations. The slow control is a decentralized torque control which approximately linearizes the reduced order model and adds a PI (proportional integral) control term for trajectory tracking. The fast control is a distributed actuator which consists of a thin piezoelectrically active film that when applied with a voltage produces a strain that dampens flexural vibrations. The control design is based upon a distributed parameter model of a two-link flexible manipulator. Computer results using a finite dimensional model obtained via modal expansion are presented to illustrate the control strategy. >
17 citations
20 Aug 1990
15 citations
TL;DR: The digital implementation of an optimal PID (proportional integral derivative) controller of linearly interpolated joint trajectories of a robot manipulator obtains optimal performance by reformulating the PID control law to minimize the time delay between the position transducer reading and the application of the corrective torque.
Abstract: The digital implementation of an optimal PID (proportional integral derivative) controller of linearly interpolated joint trajectories is presented. The controller obtains optimal performance by reformulating the PID control law to minimize the time delay between the position transducer reading and the application of the corrective torque. Compared with the PID controller that is computed in a straightforward fashion, this formulation reduces the time delay by a factor of three. The superior performance of the proposed minimum-delay PID (MD PID) is demonstrated by experiments on a robot manipulator. Other practical issues associated with a digital PID control of joint trajectories of a robot manipulator, such as integer overflow and compensation for dynamics and joint-friction, are discussed. >
11 citations
Patent•
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21 Dec 1990
TL;DR: In this paper, the authors present a fluid control system which gives a controlled variable as set even when used in an open loop by improving the nonlinearity of a proportional control valve.
Abstract: PURPOSE: To offer the fluid control system which gives a controlled variable as set even when used in an open loop by improving the nonlinearity of a proportional control valve. CONSTITUTION: This system is equipped with a hydraulic pressure line 10 as a system to be controlled, a pressure control valve 20 as the proportional control valve which controls the hydraulic pressure of the hydraulic pressure line 10, a pressure measuring means 30 which measures the hydraulic pressure of the hydraulic pressure line 10, a flow rate measuring means 40 which measures the flow rate of the hydraulic pressure line 10, and a controller 50 which controls the valve opening/closing operation of said pressure control valve 20. This controller 50 has an EEPROM where a static characteristic showing the relation of a controlled variable to an operation signal is stored and held, and a ROM stored with a program wherein a procedure for measuring the static characteristic as to the pressure control valve is described and a program wherein a procedure for generating the operation signal for obtaining the controlled variable corresponding to a target value is described, and a CPU which executes those programs. COPYRIGHT: (C)1992,JPO&Japio
7 citations
TL;DR: In this article, a simple electrohydraulic draft control system was constructed and tested to better understand agricultural equipment control, and a procedure for mathematically modeling this electric hydraulic control system is investigated.
Abstract: To better understand agricultural equipment control, a simple electrohydraulic draft control system was constructed and tested. A procedure for mathematically modeling this electrohydraulic control system was investigated. Controller tuning techniques were utilized to theoretically estimate proportional controller gains. The effect of varying the controller gain was investigated for a constructed draft control system response. The theoretical controller gains produced conservative responses in actual testing.
Patent•
28 Sep 1990
TL;DR: In this paper, the authors used an engine speed indicator unit to regulate the pump discharging capacity more accurately and easily by setting the pressure difference between the pump pressure and the actuator load pressure.
Abstract: PURPOSE: To regulate the pump discharging capacity more accurately and easily by setting the pressure difference between the pump pressure and the actuator load pressure using an engine speed indicator unit. CONSTITUTION: The pressure oil, discharged from a variable displacement pump 2 driven by a power source 1 and varied in discharge capacity by a regulator 12 driven by a regulator valve 13, and the loaded pressure oil of actuators 3 and 4 through shuttle valves 21 and 22 are led into the regulator valve 13. Also, a controller 33 receives signals from a throttle dial 31 for setting the rotational speed of the power source 1 and an electronic proportional control governor 32, outputs the command signals to a pressure proportional valve 35 to control the hydraulic pressure of a pump 17, and drives a regulator 16 to regulate the pressing force of a spring 15 of the regulator valve 13. Thus, the pressure difference between the pump pressure and the actuator load pressure can be set according to the rotational speed of the power source 1 to vary the discharging capacity more accurately and easily. COPYRIGHT: (C)1992,JPO&Japio
20 Aug 1990
23 May 1990
TL;DR: An expert system which tunes a Proportional-Integral-Derivative (PID) controller online for a single-input-single-output multiple-lag process with dead time to obtain a more desirable time response is described.
Abstract: This paper describes an expert system which tunes a Proportional-Integral-Derivative (PID) controller online for a single-input-single-output multiple-lag process with dead time. The expert system examines features of the previous transient responses and their corresponding sets of controller parameters. It determines a new set of controller gains to obtain a more desirable time response. This technique can be used to determine and implement a different set of PID gains for each operating regime and, once in steady state, the system can be used to find optimal parameters for load disturbance rejection. The expert system can be applied to any system of the specified form (aerospace, industrial, etc.) and can be expanded to include additional process models.
Patent•
31 Dec 1990
TL;DR: In this paper, a PI controller for multiple driveshafts is presented for gantry cranes, with proportional control below a certain threshold, and integral control above this threshold, where the action is by proportional control under a threshold.
Abstract: A reference control circuit (11) is provided for the first driveshaft and a subsidiary circuit (11.1,11.2...) for each additional driveshaft. The gain of the reference circuit is derived from the multiplier (4) and the constant storage unit (10) and this is directed into each subsidiary circuit by an adder (20) and a multiplier (4.1). Integrators (16) in the subsidiary circuits supply an output to each adder (20). The action is by proportional control below a certain threshold, and integral control above this threshold. USE/ADVANTAGE - PI controller for multiple driveshafts, esp. for gantry cranes; rapid and smooth positioning.
01 Jul 1990
TL;DR: A Cartesian-space control scheme is developed to control the motion of kinematically redundant manipulators with 7 degrees of freedom with computationally efficient implementation because its implementation does not require the computation of the manipulator dynamics.
Abstract: A Cartesian-space control scheme is developed to control the motion of kinematically redundant manipulators with 7 degrees of freedom (DOF). The control scheme consists mainly of proportional-derivative (PD) controllers whose gains are adjusted by an adaptation law driven by the errors between the desired and actual trajectories. The adaptation law is derived using the concept of model reference adaptive control (MRAC) and Liapunov direct method under the assumption that the manipulator performs noncompliant and slowly-varying motions. The developed control scheme is computationally efficient because its implementation does not require the computation of the manipulator dynamics. Computer simulation performed to evaluate the control scheme performance is presented and discussed.
Patent•
28 Jun 1990
TL;DR: In this article, a servo valve control device equipped with a proportional controller and an integral controller and in addition with an integral action controller to perform and stop the integral action of the integral controller is presented.
Abstract: PURPOSE:To make steady-state deviation due to external disturbance into 0 or extremely small and an amount of overshoot for control small by having a servo valve control device equipped with a proportional controller and an integral controller and in addition provided with an integral action controller to perform and stop the integral action of the integral controller. CONSTITUTION:A proportional controller 6 transfers to a servo valve 2 output proportional to a positional difference DELTAP which is integrally controlled by an integral controller 7, the output of which is added up to the output of the proportional controller 6 and is input to the servo valve 2. An integral action controller 8 performs integral action while a desired value P* of a hydraulically- pressurized cylinder is constant, as shown in (A) portions, and stops the integral action while the position P* is changed, as shown in (B) portions. The integral controller 78 performs proportional plus integral control during performing the integral action in accordance with the control of the integral action controller 8 to absorb steady-state deviation due to external disturbance, and performs the proportional control during stopping the integral action to make control of a small amount of overshoot and high stability.
Patent•
29 Jun 1990
TL;DR: In this paper, the reference opening of a proportional control valve is changed by the first control means 27 based on memory to change the basic cooling capacity of the liquid temperature regulator A so that the cooling capacity compensating the estimated heat generation quantity by the new rotating speed is obtained when the rotating speed of a main spindle is changed.
Abstract: PURPOSE: To perform the delicate control of the main spindle temperature by changing the reference opening of a proportional control valve based on memory to change the basic cooling capacity of a liquid temperature regulator so that the cooling capacity compensating the estimated heat generation quantity by the new rotating speed is obtained when the rotating speed of a main spindle is changed. CONSTITUTION: The relation between the rotating speed of a main spindle and the cooling capacity required to compensate the heat corresponding to it and the relation between the opening of a proportional control valve 11 and a liquid temperature regulator A are stored in a memory 26 in advance. The reference opening of the proportional control valve 11 is changed by the first control means 27 based on memory to change the basic cooling capacity of the liquid temperature regulator A so that the cooling capacity compensating the estimated heat generation quantity by the new rotating speed is obtained when the rotating speed of the main spindle is changed. COPYRIGHT: (C)1992,JPO&Japio
Patent•
17 Jan 1990
TL;DR: In this paper, the average value of three-phase line voltage outputted from a single-phase inverter was detected through a threephase PT and a smoothed detection voltage signal was obtained through a rectifier circuit and a filter circuit.
Abstract: PURPOSE:To eliminate distortion of waveform by detecting the average value of three-phase line voltage outputted from a three-phase inverter then subjecting the average value to proportional integration control and subjecting each phase voltage to proportional control while performing constant voltage control. CONSTITUTION:Three-phase AC voltage obtained through combination of three single-phase inverters is detected through o three-phase PT 40, and a smoothed detection voltage signal is obtained through a rectifier circuit 41 and a filter circuit 42. A PI regulation circuit 24 controls the difference between the detected voltage signal and a set voltage signal to zero. A clock pulse oscillation circuit 28, a counter 27 and a carrier generating circuit 31 are provided commonly. Furthermore, a multiplication type D/A converter 25A and the like are provided to the first phase inverter in the three single-phase inverters, and a pulse width modulated firing signal is fed to the inverter. Other sections are constituted similarly. Consequently, proportional control of each phase voltage is carried out for each single-phase inverter and proportional integration control of average line voltage is carried out integrally for three phases.
Patent•
13 Apr 1990
TL;DR: In this article, the rotary speed of a motor is monitored every predetermined sampling period, during proportional plus integration control (PI control) operation, and deceleration of the motor exceeding over a preset level is detected.
Abstract: PURPOSE:To prevent generation of large rotation ripple by performing P control of a speed loop upon detection of deceleration of a motor exceeding over a limit value while performing PI control in other cases. CONSTITUTION:Actual rotary speed of a motor 9 is fed back, as a speed signal V outputted from a tacho-generator 10, through an A/D converter 11 and compared, in a subtractor 5, with a speed reference signal VREF fed from a host sequence control processor. When variation of the rotary speed of the motor 9 is monitored every predetermined sampling period, during proportional plus integration control (PI control) operation, and deceleration of the motor 9 exceeding over a preset level is detected, switching is made to PI control proportional control (P control). Since compensation is made with a proportional value and an integrated value for the difference, rotation ripple of motor can be minimized.
27 Nov 1990
TL;DR: Some practical alternatives for minimizing steady-state errors when tracking various types of inputs with digital servo systems are presented.
Abstract: Some practical alternatives for minimizing steady-state errors when tracking various types of inputs with digital servo systems are presented. Error correction is accomplished by either feedforward control action(s) or by manipulating the reference (setpoint) input, using the steady-state error values expressed as functions of controller gains. Results obtained analytically are verified experimentally using a microcomputer-controlled motor drive system. >
Patent•
27 Nov 1990
TL;DR: In this paper, a variable throttle which changes its opening according to the displacement of a valve body between a fluid inlet and an outlet for the control pressure, and a back pressure generating throttle between the outlet and a fluid discharge port, and urge-driving the valve body by means of controller.
Abstract: PURPOSE:To control pressures to a number of fluid machines with a single valve body by disposing a variable throttle which changes its opening according to the displacement of a valve body between a fluid inlet and an outlet for the control pressure, and a back pressure generating throttle between the outlet and a fluid discharge port, and urge-driving the valve body by means of controller. CONSTITUTION:One of solenoids 31L and 31R is energized with a current from a controller 27 commensurate with the steering angle, steering force, etc. of a steering wheel, and urges a valve body 30 of a pressure control valve 26 with an urging force in proportion to the energizing current. The valve body 30 displaces according to the urging force. Variable throttles 32L and 32R changes their openings according to the displacement of the valve body 30 to change the flow rate of fluid through back pressure generating throttles 37L and 37R. Pressures commensurate with the flow rates are outputted as control pressures from outlets 36L and 36R. Thus the control pressure can be determined with the displacement of a single valve body to accurately perform proportional control, etc.
Patent•
06 Aug 1990
TL;DR: In this article, a 3-position type regulating device is used to enable execution of two different capacity control at one set value by a method wherein a signal is sent to a proportional control group at a specified time in a cycle time, and two control is interlocked so as to prevent the occurrence of interference with each other.
Abstract: PURPOSE:To enable execution of two different capacity control at one set value by a method wherein by using a 3-position type regulating device, a signal is sent to a proportional control group at a specified time in a cycle time and is sent to the number of sets controller at intervals of a cycle time, and two control is interlocked so as to prevent the occurrence of interference with each other CONSTITUTION:A front stage vaporization type closed cooling tower 1 suited for proportional control and a compression chiller 8 by a plurality of sets of rear stage compressors 9 suited for step control are controlled by one automatic regulator 14 and one temperature sensor 12 in a manner that capacity regulation of a front state and that of a rear stage are prevented from overlap with each other and the occurrence of interference with each other In this method, a 3-position type is used for the sensor 12 and the automatic regulator 14, a signal is sent only in a specified time to a front stage blower 2, a pump 3, and a capacity of regulating device 23 of a regulating valve 6 through a repeat timer circuit 17 having a cycle time decided in consideration of the time constant of a whole of cooling device, and is sent directly to a rear stage number of sets control circuit 24 at intervals of a cycle time Further, an interlock circuit 18 applies interlock in a circuit form manner so that interference between control at a front stage and that at a rear stage is prevented from occurring
27 Nov 1990
TL;DR: The problem of MCS speed control as applied to a DC machine is investigated from an error-convergence viewpoint, and it is shown that no knowledge of the plant dynamics is required, apart from an estimate of the low-frequency gain.
Abstract: A method of obtaining the convergence rates of the minimal-controller synthesis (MCS) strategy, as applied to a first-order SISO (single-input-single-output) plant, is described. The MCS algorithm is a significant development of model reference adaptive control, and is based on the hyperstability theory of Popov. Bounds are provided on the speed of convergence of the closed-loop error dynamics. It is shown that no knowledge of the plant dynamics is required, apart from an estimate of the low-frequency gain. An estimate of the plant output settling-time is derived. The problem of MCS speed control as applied to a DC machine is investigated from an error-convergence viewpoint. >
Patent•
07 Aug 1990
TL;DR: In this article, the authors proposed a method to detect an abnormality such as a defective operation, warn it, and improve reliability by judging the presence of the abnormality based on the fine vibration in the opening detected signal in the control device of an electromagnetic proportional control valve superimposed with fine vibration and adjusting the opening.
Abstract: PURPOSE:To detect an abnormality such as a defective operation, warn it, and improve reliability by judging the presence of the abnormality based on the fine vibration in the opening detected signal in the control device of an electromagnetic proportional control valve superimposed with fine vibration and adjusting the opening. CONSTITUTION:A control circuit 15 sets the necessary secondary air quantity and the target opening of an electromagnetic proportional control valve 1 based on various engine state signals from a detector group 13 via a drive processing circuit 14, fine vibration is superimposed by a control valve driving circuit 16, a current is fed to the coil of the electromagnetic proportional control valve 1, the opening is detected by an opening detector 9 and fed back to the control circuit 15 via a drive processing circuit 21 for feedback control. The opening detected signal is inputted to an abnormality judging circuit 22, the contained vibration component is compared with the fine vibration signal applied by the driving circuit 16, and the presence of an abnormality is judged. When the abnormality is judged, a warning device 55 is operated. The reliability of the opening control of the electromagnetic proportional control valve can be improved.
Patent•
08 May 1990
TL;DR: In this article, the authors improve the accuracy of a temp control by detecting a difference in the load quantity of heat energy per unit time of a recording material inserted between a pair of fixing rollers and selectively switching plural sets of temp control systems.
Abstract: PURPOSE:To improve the accuracy of a temp control by detecting a difference in the load quantity of heat energy per unit time of a recording material inserted between a pair of fixing rollers and selectively switching plural sets of temp control systems in correspondence thereto CONSTITUTION:The detection voltage corresponding to the surface temp of the fixing roller 25a is transmitted to a control signal forming circuit 3 by a temp detecting means 2 disposed in proximity to the surface of the roller 25a The control circuit 6 judges the kinds of thick paper, ordinary paper and thin paper by a paper thickness detecting roller 30 and identifies continuous/ intermittent transportation, high-speed/low-speed transportation by the signal from a controller 10 The circuit 6 selects the kinds of the control systems, such as proportional control, on-off control, and proportional and on-off control and executes the temp control by generating a reference voltage to a reference temp via a threshold generating circuit 4 The accurate control is efficiently executed in this way
Patent•
23 May 1990
TL;DR: In this paper, the authors propose to improve controllability by making a controller compensate the value of a current being inputted into a magnet proportional control valve so as to recover a delay of up and down of pilot hydraulic pressure on the basis of signal voltage subjected to feedback, in a hydraulic circuit for farm working machinery.
Abstract: PURPOSE:To improve controllability by making a controller compensate the value of a current being inputted into a magnet proportional control valve so as to recover a delay of up and down of pilot hydraulic pressure on the basis of signal voltage subjected to feedback, in a hydraulic circuit for farm working machinery or the like. CONSTITUTION:When an opening lever 1 is moved out of its neutral position, the displacement is detected by a potentiometer, inputting signal voltage into a controller 3, and an electric current conformed to magnitude of the signal voltage is transmitted to a magnet selector control valve 4 or 5. Now, supposing that the current is inputted into a magnet proportional control valve 5, pressure oil acts on a main valve 7 by way of this magnet proportional valve 5 and a pilot circuit 5a, but there is a time lag in movement of the magnet proportional control valve 5 to displacement of the operating lever 1, so that a rise in pilot hydraulic pressure comes slow. Accordingly, it is inputted into the controller 3 from a pressure sensor 9, whereby the controller 3 further inputs a large current into the magnet proportional control valve 5, accelerating its movement, thus the pilot hydraulic pressure is raised up in the wake of displacement of the operating lever 1.
TL;DR: In this paper, a model-following control scheme for hydraulic drives is presented, in which low-cost proportional valves are used instead of much more expensive servovalves, in order to reduce the electronic expense.
Patent•
15 Oct 1990
TL;DR: In this paper, an AC power source that is superimposed on a control voltage for a proportional control valve by providing a switching power source for a main power source of a control circuit and the like is presented.
Abstract: PURPOSE:To obtain the AC power source that is superimposed on a control voltage for a proportional control valve by providing a switching power source for a main power source of a control circuit and the like, additionally adapting an AC superimposed transformer to apply an AC voltage to the proportional control valve and allowing the proportional control valve to be opened and closed in accordance with the operation of a burner. CONSTITUTION:A switching power source 1 supplies electric power to a control circuit 6 and a proportional control valve 2. The current path of a DC that is supplied to the proportional control valve 2 is provided from a diode 7 and the secondary winding S of an AC superimposed transformer 3 to the proportional control valve 2 and returns to the ground through a drive transistor 10. The proportional control valve 2 changes its opening and closing degree in proportion to a current, and the current path of an AC that is supplied to the proportional control valve 2 is provided from the secondary winding S of the AC superimposed transformer 3 to the proportional control valve 2 through a bypass capacitor 8 and a current limiting resistor 9, and returns to the secondary winding S of the AC superimposed transformer 3. Thus, the power source of an AC that is superimposed on the proportional control valve 2 can be obtained.
Patent•
22 Oct 1990
TL;DR: In this article, the authors propose to reduce the error of a control response by finding a time scale factor in a partial model matching method by using a specific equation when a process that is a controlled system can be approximated with a (1st-order lag+dead time) system.
Abstract: PURPOSE:To reduce the error of a control response by finding a time scale factor in a partial model matching method by using a specific equation when a process that is a controlled system can be approximated with a (1st-order lag+dead time) system. CONSTITUTION:A control parameter decision system 4 finds the time scale factor (sigma) in the partial model matching method by, for example, equation I(approximate equation) based on the parameter, the gain K, the time constant T, and the dead time L of the transfer function Gp(S) of the process 1 approximately expressed with the (1st-order lag+dead time) system obtained by a process identification system 3, and decides the control parameter, the proportional gain Kp, the integral action time Ti, the derivative action time Td of a PID controller 2 by using the time scale factor (sigma). In equation I, it is assumed as n=L/T. In such a way, the characteristics of the dead time L and the time constant T can be affected on the control parameter of the PID controller, and a safe control response can be secured by suppressing the change of the amount of overshoot.