Proportional control

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

Proportional control valve with pressure compensation

Abstract: A directional valve (170) includes an actuator (92, 144) responsive to feedback pressure from a closed volume load (182) for regulating fluid pressure of the load proportional to an electric signal (172). A double-acting cylinder (64, 148) has a plunger (58, 150) operatively associated with the actuator (92, 144) for opposing movement of the actuator proportional to the feedback pressure of the closed volume load. Opposite faces (66, 68 and 156, 158) of the plunger (58, 150) are arranged to balance the directional valve (170) against working pressure within the valve and to control the magnitude of the feedback force opposing movement of the actuator (92, 144).

Minimum Entropy-Based Cascade Control for Governing Hydroelectric Turbines

Abstract: In this paper, an improved cascade control strategy is presented for hydroturbine speed governors. Different from traditional proportional-integral-derivative (PID) control and model predictive control (MPC) strategies, the performance index of the outer controller is constructed by integrating the entropy and mean value of the tracking error with the constraints on control energy. The inner controller is implemented by a proportional controller. Compared with the conventional PID-P and MPC-P cascade control methods, the proposed cascade control strategy can effectively decrease fluctuations of hydro-turbine speed under non-Gaussian disturbance conditions in practical hydropower plants. Simulation results show the advantages of the proposed cascade control method.

Sensitivity Analysis of the Transmission Chain of a Horizontal Machining Tool Axis to Design and Control Parameters

Abstract: This paper reports how a numerical controlled machine axis was studied through a lumped parameter model. Firstly, a linear model was derived in order to apply a modal analysis, which estimated the first mechanical frequency of the system as well as its damping coefficients. Subsequently, a nonlinear system was developed by adding friction through experimentation. Results were validated through the comparison with a commercial servoaxis equipped with a Siemens controller. The model was then used to evaluate the effect of the stiffness of the structural parts of the axis on its first natural frequency. It was further used to analyse precision, energy consumption, and axis promptness. Finally a cost function was generated in order to find an optimal value for the main proportional gain of the position loop.

Comparison of Flow-Dependent Controllers for Remote Real-Time Pressure Control in a Water Distribution System with Stochastic Consumption

Abstract: The control of pressure at a remote critical node using a pressure control valve is a highly effective way to attain pressure management. To perform real-time control, various kinds of controllers can be used, including flow-dependent controllers. These controllers calculate valve setting adjustment based both on the deviation of the pressure from the set-point and on the flow rate at the valve site. After putting all the flow-dependent controllers present in the scientific literature within the same framework, this paper presents a numerical comparison of their performance under realistic conditions of stochastic demand. Two controllers were selected for the comparison, namely the simple LCF (parameter-less proportional controller with known constant pressure control valve flow); and LVF (parameter-less controller with known variable pressure control valve flow), which uses a flow rate forecast. Indeed, this study considered an upgrade of LVF, in which the flow rate forecast was tailored to the conditions of stochastic demand. The application in a specific example network proved the performance of these controllers to be quite similar, although LCF was preferable due to its simple structure. For LCF, the average pressure at the critical node had a clear relationship to the consumption pattern. LVF outperformed when the hourly variation dominates the fluctuations in the flow. The conditions under which this out-performance occurred are comprehensively discussed.

Anti-windup Integral-Proportional Controller for Variable-Speed motor Drives

Abstract: The Windup phenomenon appears and degrades control performance when a controller with integrating action is used and the plant input is limited An anti-windup integral-proportional (IP) controller is proposed for the variable-speed motor drives and it is experimentally applied to the speed control of a vector-controlled induction motor driven by a pulse width modulated (PWM) voltage source inverter (VSI) The consistency range of the IP controller is firstly derived and the integral state is controlled to satisfy always the consistency range according to whether the controller output is saturated or not. Although the operating condition like motor load or speed command is changed under the limited plant input, it is experimentally verified that the speed response has much improved performance, such as no overshoot and fast settling time, and the maximum plant input is also effectively utilized