Proportional control

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

Proportional power control algorithm for time varying link gains in cellular radio systems

Abstract: Thus far, most of the power control (PC) algorithms derived from numerical algebra envisage a system where the link gains are fixed, and the PC command can take any value in the real field. These two assumptions are quite unrealistic in actual communication systems, since link gains are time varying and PC commands must be sent over capacity limited channels. Most of the power control algorithms derived from control theory, on the other hand, analyze the PC problem from the point of view of one link. In this paper, we propose a fully distributed and nonlinearly proportional PC algorithm for time-varying link gain environments that can possibly be implemented also as a 1-bit increase/decrease PC command, and analyze it from system point of view. We construct a simple direct bridge between the link gain changes and the parameters of the proposed algorithm. It is shown that the proposed algorithm drives the carrier-to-interference+noise+ratio (CIR) to an interval in time-changing link gain environments. Simulation results for urban speeds show that the proposed algorithm is more robust against link gain changes as compared to the linear distributed PC algorithm of Foschini and Miljanic as a reference algorithm. The proposed algorithm was also verified with an advanced dynamic system simulator.

Non-linear process controller

Abstract: PROBLEM TO BE SOLVED: To adaptively adjust the control parameter of a PI control unit for a process whose non-linearity is strong. SOLUTION: A process status/external input estimating means 4 estimates non-measurement data related to a process status. A process status recording means 5 stores data from means 2, 3 and 4 as time series data. A process constant supplying means 6 calculates a process gain K and a process time constant T by using a sewage treatment non-linear process model 61. A control parameter deciding means 7 decides a proportional gain Kp and an integral time TI being control parameters based on this. COPYRIGHT: (C)2005,JPO&NCIPI

A dead-band model and its online detection for the pilot stage of a two-stage directional flow control valve

Abstract: The dead-band in the electro-hydraulic proportional control valve is one of the main factors that affect its dynamic performance. Especially in the pilot stages of two-stage directional flow control valves, the insistent dead-band will result in a conservative valve controller design. In this paper, a detailed dead-band model describing the relationship between pilot valve spool and the flow rate of the pilot control valve is proposed. And an improved dead-band description involved with the housing clearance of the valve spool is developed to prove the dead-band uncertainty for a single valve system. Then a simple and effective method is proposed to detect the varying dead-band values in the pilot stage. This method is specially designed with a limited main spool displacement and short time interval so that it can be used for online detection without affecting the hydraulic system where the two-stage valve is involved. With the regular dead-band inverse function, comparative experimental results show that...