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Showing papers on "Proportional control published in 1995"


Journal ArticleDOI
TL;DR: In this article, a flow-graph modeling technique is employed to study the large-signal and small-Signal dynamic behavior of one-cycle controlled switching converters, and the average of the diode voltage follows the control reference in one cycle.
Abstract: One-cycle control is a nonlinear control method. The flow-graph modeling technique is employed to study the large-signal and small-signal dynamic behavior of one-cycle controlled switching converters. Systematic design method for one-cycle control systems is provided with the Cuk converter as an example. Physical insight is given which explains how one-cycle control achieves instant control without infinite loop gain. Experimental results demonstrate that a Cuk converter with one-cycle control reflects the power source perturbation in one-cycle and the average of the diode voltage follows the control reference in one cycle. >

272 citations


Journal ArticleDOI
TL;DR: In this paper, the integral time and the derivative time of a three-mode PID controller were expressed in terms of the time constant and dead time of the process, and the optimal tuning correlative formulas of the proportional gain for single and cascade control systems were obtained by the least square regression method.
Abstract: Design of one parameter tuning of three-mode PID controller was developed in this present study. The integral time and the derivative time of the controller were expressed in terms of the time constant and dead time of the process. Only the proportional gain was observed to be dependent on the implemented tunable parameter in which the stable region could be predetermined by the Routh test. Extension of the concept towards designing cascade PID controllers was straightforward such that only two parameters for the inner and outer PID controllers required to be tuned, respectively. The optimal tuning correlative formulas of the proportional gain for single and cascade control systems were obtained by the least square regression method.

48 citations


Proceedings ArticleDOI
21 Jun 1995
TL;DR: In this article, an adaptive controller is developed for the system that uses full-state feedback for simultaneous parameter identification and tracking control, which takes into account the hydraulic fluid compressibility with an online identification scheme.
Abstract: Hydraulic servovalve controlled systems contain many time-varying dynamic characteristics that are difficult to model. Controllers for such systems must either adapt to these changing parameters or be robust enough to handle the parameter variations. In order to achieve the highest possible bandwidth, an adaptive controller is developed for the system that uses full-state feedback for simultaneous parameter identification and tracking control. This controller takes into account the hydraulic fluid compressibility with an online identification scheme. Experimental results demonstrate a four fold improvement in bandwidth as compared to a conventional fixed gain proportional controller.

43 citations


Journal ArticleDOI
TL;DR: These results experimentally demonstrate that proportional gain force control and impedance control, with and without dynamics compensa tion, have equivalent response to commanded force trajectories.
Abstract: This article discusses the essential equivalence of second-order impedance control with force feedback and proportional gain explicit force control with force feedforward. This is first done analytically by reviewing each control method and showing how they mathematically correspond for constrained manipula tor control. For stiff environments the correspondence is exact. However, even for softer environments, a similar response of the system is indicated. Next, the results of an implementation of these control schemes on the CMU DD Arm II are pre sented, confirming the predictions of the analysis. These results experimentally demonstrate that proportional gain force control and impedance control, with and without dynamics compensa tion, have equivalent response to commanded force trajectories.

38 citations


Proceedings ArticleDOI
21 May 1995
TL;DR: Improvements of robustness against payload and of positioning accuracy have been attained in a positioning control system positively focusing on the pressure control of a pneumatic driving system.
Abstract: The goal of this paper is to attain a robust positioning control of a pneumatic driving system. A positioning control system positively focusing on the pressure control is investigated from the view that the pressure control is indispensable for improvement of control performances. A disturbance observer is employed to improve the pressure response and compensate the influence of friction force and parameter change. Consequently the improvements of robustness against payload and of positioning accuracy have been attained.

35 citations


Proceedings ArticleDOI
06 Nov 1995
TL;DR: In this article, various control strategies are compared with respect to their effectiveness, efficiency, and implementability, including proportional control, optimal LQR control, variable-structure control, neural network control and adaptive fuzzy control.
Abstract: Environmental forces, like wind and earthquakes, induce motion in tall civil structures. To mitigate these vibrations, an active control scheme is built into the structure. In this paper, various control strategies are compared with respect to their effectiveness, efficiency, and implementability. The control techniques that are considered include proportional control, optimal LQR control, variable-structure control, neural network control, and adaptive fuzzy control. The effect of using a linear and a nonlinear model of the system is also investigated. Numerical simulations are performed for a building equipped with a tuned mass damper. Both wind and earthquake excitations are considered in the study.

32 citations


Patent
13 Oct 1995
TL;DR: In this article, the main control valve is returned to the neutral position by causing electromagnetic proportional control valve (48a) or (48b) which are both controlled by control signals from controller (21), to block the pilot pressure.
Abstract: During manual operation, pilot pressure discharged from a pilot pump (41) is fed from a manual operation valve (44a) or (44b) through an electromagnetic change valve (49a) or (49b) to a main control valve (33). During automatic operation, pilot pressure which is output from an automatic-mode selecting valve (46) is fed through an electromagnetic proportional control valve (48a) or (48b) as well as an electromagnetic change valve (49a) or (49b), all of which are controlled by a controller (21), to main control valve (33). When limiting the operation range of the attachment during manual operation, pilot pressure output from manual operation valve (44a) or (44b) is fed through electromagnetic proportional control valve (48a) or (48b) as well as electromagnetic change valve (49a) or (49b) to main control valve (33). At that time, main control valve (33) is returned to the neutral position by causing electromagnetic proportional control valve (48a) or (48b), which are both controlled by control signals from controller (21), to block the pilot pressure.

26 citations


Proceedings ArticleDOI
18 Jun 1995
TL;DR: In this article, a position control scheme of an ultrasonic motor, which controls both driving frequency and phase difference, to achieve a quick and precise position control, is presented, which consists of a PI controller and an adaptive controller, which compensates the speed characteristic variations.
Abstract: The ultrasonic motor (USM) has an excellent performance and many useful features. Since this motor is superior in holding torque and high response characteristic, it has been expected to be used as a position servomotor for small motors. The driving principle of an ultrasonic motor is, however, different from those of electromagnetic type motors and its mathematical model has not been developed yet. Moreover, its speed characteristics vary with driving conditions. Therefore, it is difficult to control ultrasonic motor with high performance. This paper presents a new position control scheme of an ultrasonic motor, which controls both driving frequency and phase difference, to achieve a quick and precise position control. This control scheme consists of a PI controller and an adaptive controller, which compensates the speed characteristic variations. The effectiveness of this control scheme is demonstrated by experiments. >

16 citations


Patent
20 Mar 1995
TL;DR: In this paper, an electromagnetic proportional control valve 30 is used to provide resistance force to the flow of the working fluid according to its degree of opening, generating damping force, and various control amounts calculated in the controller 40 are analyzed, for example, control state amounts such as pressure before and after the electromagnetic proportional controlling valve 30, opening area, piston speed, piston stroke amount etc.
Abstract: PURPOSE: To adjust and control a vibration damping device and to retain proper operation by grasping actually controlled damping force characteristics from pressure before and after a control valve, the opening area of the control valve, piston speed, piston stroke etc. CONSTITUTION: Right and left cylinder chambers 13a, 13b are communicated with each other through a communicating circuit 15. An internally filled working fluid moves between both the cylinder chambers in accordance with displacement evolved by a piston 11. The communicating circuit 15 is provided with an electromagnetic proportional control valve 30 to provide resistance force to the flow of the working fluid according to its degree of opening, generating damping force. Inputted to a controller 40 are signals from a displacement sensor 31 for detecting displacement afforded by the electromagnetic proportional control valve 30, pressure sensors 32a, 32b for detecting pressure in both the cylinder chambers. Various control amounts calculated in the controller 40 are analyzed, for example, control state amounts such as pressure before and after the electromagnetic proportional control valve 30, opening area, piston speed, piston stroke amount etc. Suitability of a damping action to its structure is determined to provide the optimum damping force characteristics.

16 citations


Proceedings ArticleDOI
Min-Jea Tahk1, Hyeok Ryu1, Eunjung Song1
26 Jul 1995
TL;DR: In this article, the authors derived conditions for target observability with angle-only measurements for several target models: stationary target, constant-velocity target, and constant acceleration target.
Abstract: Conditions for target observability with angle-only measurements are derived for several target models: stationary target, constant-velocity target, and constant acceleration target. The effects of proportional navigation on target observability are then analyzed. The analysis results show that target observability is dependent on the choice of target model and guidance gain and can be significantly degraded for certain guidance gains.

15 citations


Proceedings ArticleDOI
28 Sep 1995
TL;DR: The new method deals with plant uncertainty explicitly, thus providing proportional gain and reset time combinations that perform well not only for nominal models but also for all the models described by the model parameter variations.
Abstract: This paper presents a new method of PI controller tuning and its results for two important practical cases: first-order delay with dead-time and integrating system with dead-time. The new method deals with plant uncertainty explicitly, thus providing proportional gain and reset time combinations that perform well not only for nominal models but also for all the models described by the model parameter variations. The new method also clarifies the peculiarity of tuning integrating systems.

Journal ArticleDOI
TL;DR: The tuning knowledge of the neural network is extracted from the tuning of a representative process, and examples covering a wide range of process dynamics are tested to demonstrate the excellent performance of the tuner.

Journal ArticleDOI
TL;DR: In this paper, the relative gain array (RGA) is given a geometric interpretation and demonstrated to be a convenient steady-state interaction measure, which is then quantified to predict dynamic interactions based on simple response experiments.
Abstract: A technique is developed to evaluate the interactions of a multivariable control system. The technique can be employed to select the best pairing configuration of the control system, but more than that, it is capable of providing guidelines for controller design. The technique arises from a geometric analysis of the stability boundaries in the proportional gain space. As a result, the relative gain array (RGA) is given a geometric interpretation and demonstrated to be a convenient steady-state interaction measure. A convenient dynamic counterpart is then quantified to predict dynamic interactions based on simple response experiments. The validity of the proposed dynamic interaction measures is verified by numerous literature examples

Patent
19 Sep 1995
TL;DR: In this paper, a rear-end collision alarm control circuit was proposed to improve the safety by providing a brake control circuit, which outputs a control signal to an accelerator actuator and to a pressure proportional control valve in accordance with various detection signals and a stored brake pressure map.
Abstract: PURPOSE:To improve the safety by providing a brake control circuit, which outputs a control signal to an accelerator actuator and to a pressure proportional control valve in accordance with various detection signals and a stored brake pressure map, in a rear-end collision alarm device CONSTITUTION:Signals of a laser head 1 for measuring a distance from a vehicle ahead and of a car speed sensor 2 are input to a rear-end collision alarm control circuit 4 of a rear-end collision alarm device A, and a relative speed to the vehicle ahead is calculated, displayed in a distance display device 5, output to an automatic brake control circuit 14 and output to an alarm equipment 6 when judged a hazardous speed In this automatic brake control circuit 14, in accordance with signals of a brake sensor 12, accelerator sensor 13, automatic brake pressure sensor 17 and a stored brake pressure map, a control signal is calculated and output to an accelerator actuator 15 and to a pressure proportional control valve 16, to place an accelerator in an inoperative condition, so as to accurately control an automatic brake pressure Accordingly, an optimum brake operation is automatically performed in accordance with an operating condition, and rear-end collision can be safely avoided

Proceedings ArticleDOI
08 Oct 1995
TL;DR: The authors review where fuzzy logic started and then examineWhere fuzzy logic is today and how these mathematical functions are now able to closely approximate human reasoning are examined.
Abstract: As rubber and plastics compounds have evolved into very complex formulas and their uses have expanded, the need for more precise temperature control has become necessary. In today's world of rubber and plastics products, temperature and process control is very critical to the quality, appearance, and consumer acceptance of a manufacturer's products. This is one of many reasons why the temperature controls or the process controls have advanced from simple ON/OFF controllers to the more advanced microprocessor based controls and why the control algorithm has also changed. The algorithms have gone from just providing proportional control to what is called fuzzy logic control. At this point in control technology, these control algorithms have advanced to the state where these mathematical functions are now able to closely approximate human reasoning. The authors review where fuzzy logic started and then examine where fuzzy logic is today.

Proceedings ArticleDOI
13 Dec 1995
TL;DR: In this article, the use of a GA in designing control systems for a boiler-turbine power plant was studied, with specifics in developing a proportional-integral (PI) controller and a state feedback controller for a non-linear multi-input/multi-output (MIMO) plant model.
Abstract: The use of a genetic algorithm is studied in designing control systems for a boiler-turbine power plant, with specifics in developing a proportional-integral (PI) controller and a state feedback controller for a non-linear multi-input/multi-output (MIMO) plant model. The plant model is presented along with a discussion of the inherent difficulties in such controller development. A sketch of the genetic algorithm (GA) is presented and its strategy as a method of control system design is discussed.

Proceedings ArticleDOI
21 Jun 1995
TL;DR: A novel control scheme for the flexible manipulator based on variable structure system theory is proposed and tested and the controller shows the robustness towards the variation of the system parameters.
Abstract: A novel control scheme for the flexible manipulator based on variable structure system theory is proposed and tested. The controller shows the robustness towards the variation of the system parameters. Also the performance of the controller can be tuned easily without complicated calculation for stability. Experimental results are presented and they are compared with those obtained from the hybrid proportional controller which is based on the optimal control scheme.

Proceedings ArticleDOI
21 Jun 1995
TL;DR: In this paper, a neural network is used to model the steady-state inverse of an electrically heated feed preheater, which is compared to conventional proportional-integral internal model and model predictive controllers.
Abstract: This paper demonstrates a novel approach for process control that uses neural networks to model the steady-state inverse of an electrically heated feed preheater. It is compared to conventional proportional-integral internal model and model predictive controllers.

Proceedings ArticleDOI
08 Oct 1995
TL;DR: In this article, a novel disturbance torque suppresser is proposed to eliminate the effects of the disturbance torque, uncertain inertia moment, and nonlinear friction, so that the new controller makes the velocity error zero at any state even when the moment of inertia and viscous friction are varying.
Abstract: In this paper, we propose a new feedforward control scheme for the control of brushless DC motors. We adopt a novel disturbance torque suppresser to eliminate the effects of the disturbance torque, uncertain inertia moment, and nonlinear friction, so that the new controller makes the velocity error zero at any state even when the moment of inertia and viscous friction are varying. We can, thereby, overcome the drawbacks of the conventional proportional and integral (PI) and feedforward controller. Some simulation and experimental results as well as mathematical performance analysis are presented to demonstrate the superior tracking performance of our controller over the conventional PI controllers and feedforward controllers.

Proceedings ArticleDOI
21 Feb 1995
TL;DR: A hybrid controller is designed by using both the feedback linearization and fuzzy tracking control algorithms, which show improvements in torque and speed ripples over the conventional proportional-integral (PI) controller.
Abstract: In this paper the design of feedback linearization and fuzzy logic controllers for variable reluctance (VR) motors are presented. The controllers so designed based on the nonlinear control techniques are applied to a VR motor model (taking saturation into account) with the aim of improving dynamic performance as well as reducing torque and hence speed ripples. Test results obtained through digital simulations show improvements in torque and speed ripples over the conventional proportional-integral (PI) controller. Finally, a hybrid controller is designed by using both the feedback linearization and fuzzy tracking control algorithms. Simulation test results obtained front the hybrid controller show further improvements in reducing torque and speed ripples over the fuzzy as well as feedback linearization controllers. >

Patent
22 Dec 1995
TL;DR: In this paper, a PI control system is established, the command torque is inputted to a primary delay filter 24, and a signal which is equivalent to a command torque 25 of the IP control system was obtained as the output Also, the target 3 to be controlled is the total of the rotor inertia of a servo motor and the inertia of load.
Abstract: PURPOSE:To identify Coulomb friction and viscosity friction to be controlled and to identify the compensation and inertia by identifying the Coulomb friction using the steady value of the difference between PI control system time response and equivalent IP control system time response CONSTITUTION:The title item consists of a target 3 to be controlled where Coulomb friction exists and a controller 2 for controlling speed Then, a PI control system is established, the command torque is inputted to a primary delay filter 24, and a signal which is equivalent to a command torque 25 of the IP control system is obtained as the output Also, J which is the target 3 to be controlled is the total of the rotor inertia of a servo motor and the inertia of load, the level is constant Fc regardless of the speed, and Coulomb friction which becomes a resistance with a direction for interfering with a motion exists Further, Kv of the controller 2 is a proportional gain and Ti is the time constant of integration and primary delay filter A constant value Fc is identified according to the difference between the time difference of command torque of the PI control system and that of the equivalent IP control system

Proceedings ArticleDOI
06 Nov 1995
TL;DR: In this article, a systematic design method for efficiency-optimized speed control system synthesis is proposed based on the improved optimal regulator theory, where the system under consideration is a separately excited DC motor system.
Abstract: A systematic design method for efficiency-optimized speed control system synthesis is proposed based on the improved optimal regulator theory. The system under consideration is a separately excited DC motor system. The improved optimal regulator theory is applied to this system effectively and the systematic design procedure can be realized. The ratio of the armature current and the field current that gives the maximum efficiency is analytically derived, and the error term of the current ratio is included in the performance index. The desired signal and the disturbance signal are assumed to be step functions. The simulation results are detailed and discussed. The effect of the feed forward components on the system performance is presented.

Patent
16 May 1995
TL;DR: In this paper, a proportional control valve is used to vary a flow path resistance between an inlet port and an output port by driving a valve element to and apart from a valve seat by a stepping motor and a Geneva wheel with a grooveless tooth is provided to restrict the rotational range of the stepping motor.
Abstract: PURPOSE:To provide a reliable proportional control valve wherein a valve element does not bite into a valve seat and stress on a transmission system is eliminated by installing a rotation restricting mechanism acting mechanically on a stepping motor CONSTITUTION:In a proportional control valve to vary a flow path resistance between an inlet port and an output port 28 by driving a valve element to and apart from a valve seat by a stepping motor, a Geneva wheel 7 provided with a groove-less tooth 12 is provided to restrict the rotational range of the stepping motor 2 Thus the movable range of the valve element is restricted, and any trouble such as binding of valve due to biting of the valve element into the valve seat, etc, stress on a drive system, etc, is not produced The stepping motor thus obtained can be used also for the other applications

Patent
15 Mar 1995
TL;DR: In this article, a hydraulic valve assembly comprising an inlet (31) for connection to a source of pressure fluid, a number of subsidiary valves (43, 44) supplied from the inlet and an outlet (32) for the return of fluid from the assembly to tank, and a pair of electro-hydraulic proportional load and pressure compensated cartridge valves (36, 37) to enable proportional control of fluid entering and leaving the assembly was presented.
Abstract: An hydraulic valve assembly comprising an inlet (31) for connection to a source of pressure fluid, a number of subsidiary valves (43, 44) supplied from the inlet (31) and an outlet (32) for the return of fluid from the assembly to tank, and a pair of electro-hydraulic proportional load and pressure compensated cartridge valves (36, 37) to enable proportional control of fluid entering and leaving the assembly The invention enables increased levels of control to actuators connected to the subsidiary valves, at reduced cost and in a more compact assembly when compared with conventional valve assemblies in which separate proportional control valves are required for each subsidiary valve and each requires a separate electronic channel for its operation A valve (47) enables a float condition to be achieved on an actuator connected to service ports (41) and (42)

Journal ArticleDOI
TL;DR: In this article, an upper bound for the gain of stabilizing proportional controllers of stable linear systems with one or more unstable zeros is given, provided that the controller has sufficiently small gain.

Patent
27 Oct 1995
TL;DR: In this paper, the sensitivity and cycle of critical vibrations at the time of increasing only an integration gain KI of an integration element 1, and the sensitivity in the case of increasing a proportional gain Kp of a proportional element 2 are measured.
Abstract: PURPOSE:To adjust a control method with the simple method by calculating the value of the control parameter corresponding to the sensitivity and cycle of critical vibrations when only an integration gain is increased and when only a proportional gain is increased. CONSTITUTION:Concerning the adjusting method for control parameter at the time of I-PD control to a gas turbine 4 as a controlled system, for example, first of all, a static gain is measured by a static characteristic test. Next, the sensitivity and cycle of critical vibrations at the time of increasing only an integration gain KI of an integration element 1 and the sensitivity and cycle of critical vibrations at the time of increasing only a proportional gain Kp of a proportional element 2 are measured. Then, the optimum adjusted values of the integration gain KI, proportional gain Kp and differentiation gain Kp are calculated corresponding to these measured results. Thus, while using the simple method similar to the critical sensitivity method of Ziegler Nicols, the control parameter can be adjusted at the optimum value even concerning any controlled system to which this critical sensitivity method can be applied.

Proceedings ArticleDOI
22 Oct 1995
TL;DR: In this paper, the authors demonstrate that the systems compensated by a proportional fuzzy logic controller (PFLC) are capable of producing responses similar to those obtained by a classical proportional-plus-derivative (PD) controller.
Abstract: The objective of this paper is to demonstrate that the systems compensated by a proportional fuzzy logic controller (PFLC) are capable of producing responses similar to those obtained from the systems compensated by a classical proportional-plus-derivative (PD) controller. Analysis of the output equation of a fuzzy logic controller (FLC) shows that the PFLC output is a linear combination of the inputs over different ranges of operations. This linear combination for each specific range of operation can be designed to provide overshoot and rise time reduction similar to those obtained from the classical proportional-plus-derivative (PD) controller but without the derivative input. Simulations of a control system demonstrate the improved performance of the PFLC over the classical proportional controller.

Patent
20 Jan 1995
TL;DR: In this article, a radio control circuit which generates false proportional control signals to linearly raise the number of revoalution of a motor in response to manipulation of an ON/OFF button of a transmitter is presented.
Abstract: PURPOSE:To enable a toy to travel smoothly in a three-dimensional indoor space by providing a radio control circuit which generates false proportional control signals to linearly raise the number of revoalution of a motor in response to manipulation of an ON/OFF button of a transmitter. CONSTITUTION:A CPU 14 produces specified pulse data corresponding to ON/ OFF signals of a joy pad, and sends the pulse data according to a transmitting method such as PM, PCM and others. An amplitude detector 13 extrancts the pulse signals from received signals, and the CPU 14 deciphers the pulse data and sends motor control signals, forward/backward control signals and others to a driver 10 based on the results of decipherment. A motor driver 17 is connected to the CPU 14 and drives a direct current motor 16 at a number of revolution corresponding to false proportional control signals or turbo control signals. Thereby, variable linear inputs similar to those by a joystick can be done by simple ON/OFF key manipulation.

Proceedings ArticleDOI
05 Jan 1995
TL;DR: This work examines a class problems where the objective function is reduced to inequality constraints and also where qualitative information from artificial neural networks can be used with learning automata as an effective decision maker.
Abstract: The application of learning automata for control is shown to give significantly improved performance by two modifications (a) using a set of proportionality constants of a proportional feed-back controller, as the action set of learning automata and (b) a scheme which uses artificial neural networks as memory. This work examines a class problems where the objective function is reduced to inequality constraints and also where qualitative information from artificial neural networks can be used with learning automata as an effective decision maker. Two nonlinear process control examples are tackled. It is shown that despite deterioration of net's prediction error the learning automata-ANN control strategy works while the performance improves resulting a better accuracy. >

Patent
04 Apr 1995
TL;DR: In this article, a proportional control of a rolling-down cylinder in a hydraulic draft type rolling mill is proposed to improve the accuracy of a plate thickness by supressing the generation of offset deviation.
Abstract: PURPOSE:To improve the accuracy of a plate thickness by supressing the generation of offset deviation, at the time of proportionally controlling the position of a rolling-down cylinder in a hydraulic draft type rolling mill. CONSTITUTION:In a device 32 for controlling a hydraulic control valve, a command signal D3 for the position of a hydraulic control valve, which signal is formed from the deviation between a command signal D2 for operating a hydraulic control valve inputted from a device 30 for controlling the position of a rolling-down cylinder and a feed back signal F2 from a sensor 26 for the position of a hydraulic control valve, is inputted in a hydraulic control valve 22, controlling the position of the valve and the position of a rolling-down cylinder 16. At this time, the deviation between a command signal D1 for the position of the rolling- down cylinder, which signal is obtained by a comparator 34, and a signal F1 for detecting the position of the rolling-down cylinder is multiplied by a proportional gain function 38 by a multiplier 36, the resultant operating quantity (signal) for a proportional control is added by an adder 46 to an integral correction signal C, which is obtained by multiplying through a multiplier 44 an integral gain 48 by the integral value of the same deviation determined through an integrator 43, and the command signal D2 for operating a hydrulic control valve is formed in which the operating quantity at the time of the proportional control is corrected according to the integral value of a control deviation.