Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

유압식 로봇의 힘 제어를 위한 유압 서보 시스템의 특성에 관한 연구

  • Kim, Hyo-Gon (Dept. of Mechatronics Engineering, Hanyang Univ.) ;
  • Lee, Jong-Won (Dept. of Intelligent Robot Engineering, Korea Univ. of Science and Technology (UST)) ;
  • Park, Sangdeok (Korea Institute of Industrial Technology (KITECH)) ;
  • Han, Changsoo (Dept. of Robot Engineering, Hanyang Univ.)
  • 김효곤 (한양대학교 메카트로닉스공학과) ;
  • 이종원 (과학기술연합대학원대학교 지능형로봇공학전공) ;
  • 박상덕 (한국생산기술연구원) ;
  • 한창수 (한양대학교 로봇공학과)
  • Received : 2014.05.13
  • Accepted : 2014.09.02
  • Published : 2015.02.01
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Abstract

Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program.

유압 서보 시스템은 구동기 단에서 부피 대비 큰 힘을 출력할 수 있으므로 로봇에 적용 시, 로봇의 팔 또는 다리를 경량화할 수 있다. 이것은 로봇의 동적 특성과 에너지 효율을 향상 시키므로 고출력이 필요한 몇몇의 근력지원용 착용형 로봇과 사족 보행 로봇들은 유압 서보 시스템을 사용한다. 이 로봇들은 사용자나 외부 환경에 순응하기 위해 힘제어를 하는 것이 유리하지만 유압식 로봇은 유압서보 시스템이 갖는 비선형성으로 인해 정교한 힘제어가 쉽지 않다. 본 논문에서는 서보 밸브, 배관 그리고 유압 실린더로 구성되는 유압 서보 시스템의 시뮬레이션 모델을 개발하여 유압 서보 시스템의 힘제어 시 고려해야 할 사항에 대해 분석하였다. 그리고 비선형 모델을 이용한 힘제어 기법을 제안하고 시뮬레이션을 통해 효과를 검증하였다.

Keywords

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