가변 용적형 사판식 피스톤 펌프의 회전 속도 조절에 의한 정압 제어 소비 동력 절감

Abstract

This paper proposes a control scheme to reduce the power consumption of a variable displacement swash-plate type piston pump supplying oil to a valve-controlled hydraulic cylinder at constant pressure. Whenever flow rate demand was absent, the swash plate angle and the pump speed were changed to the minimum values required to compensate for the internal leakage flow. In response to command signals, the pump speed was changed in proportion to the absolute mean value of the speed component for position commands. At the same time, a pressure regulator was activated to maintain constant system pressure by precisely adjusting the pump speed with the swash plate angle fixed at the maximum. The conventional system consisting of a pressure-compensated variable displacement type pump is driven at a constant speed of 1,800rpm. By comparison, computer simulation and experimental results showed that idling power at stand-by status could be reduced by up to 70% by reducing the pump speed from 1,800rpm to 300rpm and the swash plate angle to the minimum. * Corresponding author: yshong@kau.ac.kr 1 Aerospace & Mechanical Engineering, Graduate School, Korea Aerospace University, Goyang-si, Gyeonggi-do 412-791, Korea 2 Aerospace & Mechanical Engineering, Korea Aerospace University, Goyang-si, Gyeonggi-do 412-791, Korea Copyright C 2014, KSFC This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http:// creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 기호 설명  : Position Command Signal, mm  : Reference System Pressure, bar  : Accumulator Pressure, bar  : Pump Flow Rate, l/min  : Cylinder Flow Rate, l/min  : Accumulator Flow Rate, l/min  : Gas Pre-charge Pressure, bar  : Effective Gas Volume, m 3  : Oil Volume in the Accumulator, m 3  : Volumetric Displacement, cc/rev  : Cross Sectional Area of Cylinder, mm 2  : Pitch Circle Diameter of Barrel, mm  : Piston Diameter, mm  : Number of Pistons  : Swash Plate Angle, deg  : Bulk Modulus of Oil, MPa