Proportional control

About: Proportional control is a research topic. Over the lifetime, 3756 publications have been published within this topic receiving 49050 citations.

Nonlinear Smooth Feedback Control of a Three-Pole Active Magnetic Bearing System

Abstract: In this study, a class of smooth feedback controllers is proposed for the stabilization of a three-pole active magnetic bearing (AMB) system. The three-pole AMB system is strongly nonlinear and nonaffine. Conventional controllers are nonsmooth and complicated, which is difficult for implementation and further study. The proposed smooth controllers are designed utilizing a linear transformation on the system inputs (coil currents). As a result, simple smooth controllers, such as quadratic state feedback controller, can be obtained. The domain of attraction of the origin under the smooth controller is estimated. The proposed smooth controller is verified through both numerical and experimental results.

Proportional control valve

Abstract: A proportional control valve has inlet and outlet solenoids controlling the pressurization and evacuation of a chamber between two pistons in a control valve of the rack and pinion opposed-piston type. The control valve can be maintained in fully open, fully closed, or intermediate positions by selectively energizing and de-energizing the solenoids. The solenoids can be of the normally open or normally closed solenoid poppet types depending on whether the control valve is to open, close or maintain its current state in the event of a power failure.

A systematic antiwindup strategy and the longitudinal control of a platoon of vehicles with control saturations

Abstract: Current methodologies for designing control systems usually ignore the effects of control saturations. For vehicle platooning, this can be especially disastrous since the performance of a platoon of nonidentical vehicles is, in general, severely limited by saturating control signals. This paper presents a systematic design procedure for adapting a nominal controller, designed without regard to control saturation, to a higher performance nonlinear controller that explicitly accounts for the saturating nonlinearities while preserving stability. In particular, the error governor (EG) scheme proposed by P. Kapasouris et al. (1988) is extended and applied to the IVHS problem found by S. Sheikholeslam (1990). This extension is a less conservative strategy that explicitly accounts for an important class of controller designs, including proportional control and a class of nonlinear feedback designs. Results of the study demonstrate that severe windup found in nominal platooning applications can systematically be eliminated without loss of steady-state performance. This significantly increases the range of maneuvers open to the lead vehicle, thus enhancing the utility of a proposed design. An extensive simulation of a 15-car platoon of nonidentical vehicles with nonlinear vehicle models illustrates these results.

Design and tuning method of PID controller for a class of inverse response processes

Abstract: Inverse response processes are difficult to be controlled due to presence of right half plant (RHP) zeros. In this paper, firstly the RHP zeros are approximated to the form of dead time in terms of Pade approximation theory. Thus, the controlled processes can be regarded as general stable processes plus dead time without RHP zeros. Then based on the internal model control (IMC) structure, an analytical PID controller design procedure is developed for the transformed inverse response processes. The resulting controller includes a single adjustable control parameter. Through stability analysis for the proposed control system, the stable range of the control parameter is derived according to a simple method called dual-locus diagram, and meanwhile, the sufficient and necessary condition for holding the proposed closed-loop system robust stability is provided. By monotonously tuning the single controller parameter, the good compromise between the nominal performance and robust stability of the closed loop system can be realized. The simulation example demonstrates the superiority of the proposed control scheme.

Incremental fuzzy PI control of a solar power plant

Abstract: Between 1987 and 1997, considerable research effort has been devoted to improving the efficiency of solar thermal power plants with distributed collectors, not only in the field of optical technology but also from the control and optimisation viewpoint. The article deals with this second aspect, and presents results obtained in the control of the distributed solar collector field of the solar power plant of Almeria (Spain) using a fuzzy logic control approach. A distributed collector field consists of a series of parabolic mirrors which reflect solar radiation onto a pipe where oil gets heated while circulating. The object of the control system is to maintain the outlet oil temperature of the field (collector field) at a desired level in spite of disturbances such as changes in the solar radiation level, mirror reflectivity or inlet oil temperature. Since solar radiation cannot be adjusted this can only be achieved by adjusting the flow of oil. An incremental fuzzy PI controller (IFPIC) has been developed to cope with this control problem in which all parameters of a PI controller are updated online as a function of the operating conditions of the controlled plant, thus improving the behaviour of the classical fixed PI controllers which are usually employed. The strategy has been implemented in series with a simple feedforward controller which compensates for the disturbances acting on the system. Simulation results using a nonlinear computer model of the field and real tests are provided.