• 제목/요약/키워드: pneumatic actuator

Search Result 127, Processing Time 0.026 seconds

Life Prediction of Elastomeric U Seals in Hydraulic/Pneumatic Actuators Using NSWC Handbook (NSWC를 활용한 유공압 액추에이터 U 형 씰의 수명예측)

  • Shin, Jung Hun;Chang, Mu Seong;Kim, Sung Hyun;Jung, Dong Soo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.38 no.12
    • /
    • pp.1379-1385
    • /
    • 2014
  • Even the rough prediction of the product test time before the lifetime test of mechanical component begins would be of use in estimating cost and deciding how to keep up with the test. The reliability predictions of mechanical components are difficult because failure or degradation mechanisms are complicated, and few plausible databases are available for lifetime prediction. Therefore, this study conducted lifetime predictions of elastomeric U seals that were respectively installed in a hydraulic actuator and a pneumatic actuator using lifetime models and a field database based on failure physics and an actual test database obtained from the NSWC handbook. To validate the results, the predicted failure rates were compared with the actual lifetime test results acquired in the lab durability tests. Finally, this study discussed an engineering procedure to determine the coefficients in the failure rate models and analyzed the sensitivity of each influential parameter on the seal lifetime.

Effect of Exoskeleton Orthosis for Assistance of Dorsiflexion Torque in Walking Pattern and Lower-limb Muscle (족배굴곡 보조용 외골격 보조기가 보행자의 보행패턴 및 하지근육에 미치는 효과)

  • Oh, H.J.;Kim, K.;Jeong, G.Y.;Jeong, H.C.;Kwon, T.K.
    • Journal of rehabilitation welfare engineering & assistive technology
    • /
    • v.8 no.3
    • /
    • pp.177-185
    • /
    • 2014
  • In this study, the exoskeleton orthosis for the assistance of dorsiflexion torque in ankle joint to prevent foot-drop was developed. It was consist of three part; 1) the power part using artificial pneumatic actuator, 2) wearing part of ankle and knee joints to fix the orthosis, and 3) control part to detect the gait phase using physiological signal. The dorsiflexion torque was generated by the artificial pneumatic actuator connected with wearing part between ankle and knee joint. The accurate timing to assist dorsiflexion torque is made up of physiological signal in foot sole part that detect the gait phase, that is, stance and swing phase in each foot. We conduct the experiment to investigate the effect of exoskeleton orthosis to the 7 elderly people and 10 healthy people. The result showed that the muscular activities in tibialis anterior muscle were reduced because of the assistance of dorsiflexion torque in ankle joint using the exoskeleton orthosis.

  • PDF

Performance Evaluation of a Piezostack Single-stage Valve at High Temperatures (고온 환경에서의 압전작동기를 이용한 1단 밸브의 성능 평가)

  • Han, Chulhee;Kim, Wan Ho;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.27 no.2
    • /
    • pp.168-174
    • /
    • 2017
  • In this work, a piezostack single-stage valve (PSSV) system is proposed and its control performance is experimentally evaluated at high temperature up to $150^{\circ}C$. In order to achieve this goal, a PSSV system is designed and operating principle and mechanical dimensions are discussed. A displacement amplifier and an adjust bolt are used to generate target displacement and to compensate thermal expansion. Then, an experimental apparatus is constructed to evaluate control performance of the PSSV system. The experimental apparatus consists of a heat chamber, a hydraulic circuit, a pneumatic circuit, pneumatic-hydraulic cylinders, thermal insulator, electronic devices, sensors, data acquisition (DAQ) board and a voltage amplifier. The flow rate and displacement control performance of the valve system are evaluated via experiment. The experimental results are evaluated and discussed at different temperatures and frequencies showing the controlled flow rate and spool displacement.

Development of a Pneumatically Driven 6 DOF Driving Simulator (공기압 구동식 6 DOF 드라이빙 시뮬레이터의 개발)

  • Kim, Geun-Mook;Kang, E-Sok
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.14 no.12
    • /
    • pp.6090-6097
    • /
    • 2013
  • A pneumatically-driven driving simulator that provides a realistic representation of the driving environment was developed. The motion platform for the driving simulator is a mechatronic device that gives a driver the realistic feeling of an actual vehicle. The cost of the motion platform comprises the largest part of the expenses in developing a driving simulator. In this project, to develop a low-cost motion platform, the self-built motion platform based on the Stewart platform configuration that is constructed by six pneumatic cylinders was used as its actuator. The Stewart platform that moves in response to the operating signals of the joystick showed satisfactory tracking performance. We confirmed the possibility of the driving simulator using rFactor that is a commercially available racing game software.

Development of Force Reflecting Joystick for Feild Robot (필드로봇을 위한 힘방향 조이스틱 개발)

  • 송인성;안경관;양순용;이병룡
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1997.10a
    • /
    • pp.357-360
    • /
    • 1997
  • Abstract: In teleoperation field robotic system such as hydraulically actuated robotic excavator, the maneuverability and convenience is the most important part in the operation of robotic excavator. Particularly the force information is important in dealing with digging and leveling operation in the teleoperated excavator. Excavators are also subject to a wide variation of soil-tool interaction forces. This paper presents a new force reflecting joystick in a velocity-force type bilateral teleoperation system. The master system is electrical joystick and the slave system IS hydraulically actuated cylinder with linear position sensor. Particularly Pneumatic motor is used newly in the master joystick for force reflection and the information of the pressure of salve cylinder is measured and utilized as the force feedback signal. Also force-reflection gain greatly affects the excavation performance of a hydraulically actuated robotic system and it is very difficult to determine it appropriately since slave excavator contacts with various environments such as from soft soil to rock. To overcome this, this paper proposes a force-reflection gain selecting algorithm based on artificial neural network and fuzzy logic.

  • PDF

Development of Ankle Power Assistive Robot using Pneumatic Muscle (공압근육을 사용한 발목근력보조로봇의 개발)

  • Kim, Chang-Soon;Kim, Jung-Yup
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.41 no.8
    • /
    • pp.771-782
    • /
    • 2017
  • This paper describes the development of a wearable robot to assist ankle power for the elderly. Previously developed wearable robots have generally used motors and gears to assist muscle power during walking. However, the combination of motor and reduction gear is heavy and has limitations on the simultaneous control of stiffness and torque due to the friction of the gear reducer unlike human muscles. Therefore, in this study, Mckibben pneumatic muscle, which is lighter, safer, and more powerful than an electric motor with gear, was used to assist ankle joint. Antagonistic actuation using a pair of pneumatic muscles assisted the power of the soleus muscles and tibialis anterior muscles used for the pitching motion of the ankle joint, and the model parameters of the antagonistic actuator were experimentally derived using a muscle test platform. To recognize the wearer's walking intention, foot load and ankle torque were calculated by measuring the pressure and the center of pressure of the foot using force and linear displacement sensors, and the stiffness and the torque of the pneumatic muscle joint were then controlled by the calculated ankle torque and foot load. Finally, the performance of the developed ankle power assistive robot was experimentally verified by measuring EMG signals during walking experiments on a treadmill.

A Novel Powered Gait Orthosis using Pneumatic Muscle Actuator

  • Kang, Sung-Jae;Ryu, Jei-Cheong;Moon, In-Hyuk;Ryu, Jae-Wook;Mun, Mu-Seung
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2003.10a
    • /
    • pp.1500-1503
    • /
    • 2003
  • One of the main goals in the rehabilitation of SCI patients is to enable the patient to stand and walk themselves. We are developing high-thrust powered gait orthosis(PGO) that use air muscle actuator(shadow robot Co., UK) to be assisted gait and rehabilitation purposes of them. We made of PD controller and measured hip joint angle by its load and the pressure to control air muscle of PGO. As a results, maximum flexion angle of hip joint is $20^{\circ}$, and angular velocity is 30.4${\pm}2.5^{\circ}/sec$, and then delay time of system was average 0.62${\pm}$0.03s. As the hip flexion angle and the pelvic angle is decreased during the gait with PGO, the patient can walk faster. By using the PGO, the energy consumption can also be decreased. therefore, the proposed PGO can be a very useful assitive device for the paraplegics to walk.

  • PDF

HILS(Hardware-In-the-Loop Simulation) Development of a Steering HILS System (전동식 동력 조향 장치 시험을 위한 HILS(Hardware-In-the-Loop Simulation) 시스템 개발)

  • 류제하;노기한;김종협;김희수
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.7 no.9
    • /
    • pp.105-111
    • /
    • 1999
  • The paper presents development of a Hardware-In-the-Loop simulation (HILS) system for the purpose of testing performance, stability, and reliability of an electronic power steering system(EPS). In order to realistically test an EPS by the proposed HILS apparatus, a simulated uniaxial dynamic rack force is applied physically to the EPS hardware by a pnumatic actuator. An EPS hardware is composed of steering wheel &column, a rack & pinion mechanism, andas motor-driven power steering system. A command signal for a pneumatic rack-force actuator is generated from the vehicle handling lumped parameter dynamic model 9software) that is simulated in real time by using a very fast digital signal processor. The inputs to the real-time vehicle dynamic simulation model are a constant vehicle forward speed and from wheel steering angles driven through a steering system by a driver. The output from a real-time simulation model is an electric signal that is proportional to the uniaxial rack force. The vehicle handling lumped parameter dynamic model is validated by a fully nonlinear constrained multibody vehicle dynamic model. The HILS system simulation results sow that the proposed HILS system may be used to realistically test the performance stability , and reliability of an electronic power steering system is a repeated way.

  • PDF

A Study on the Control Characteristics of FHA by Using ERF and Industrial Controller (ERF와 산업용 콘트롤러를 이용한 FHA의 제어특성에 관한 연구)

  • Jang Sung-Cheol
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.14 no.1
    • /
    • pp.95-100
    • /
    • 2005
  • Making the best use of the features of the electro-rheological(ER) valve, a two-port pressure control valve using ER fluids is proposed and manufactured. The ER-Valve characteristics are evaluated by changing the intensity of the electric field and the number of electrode. In addition, the performance of the plate type ER-Valve is investigated by change the particle concentration of the ER fluid. As only with electrical signal change to the ER-Valve in which ER fluid flowing, ER fluid flow is controlled, so development of simple ER-Valves have been tried. The ER-Valves and pressure drop check method are considered to be applied to the fluid power control system. Using the minかnぉd pressure control valve, a one-link manipulator with FHA in robot system is driven. As a result, it is experimentally confirmed that the pressure control valve using ER fluids is applicable to use in driving actuator. If it applies characteristics of the ER fluids, it will be able to apply in the control system fir the ER Valve which occurs from industrial controller(PLC).

Manufacturing 2DOF Inflatable Joint Actuator by Pneumatic Control (공압제어를 통한 2DOF 팽창식 관절 액추에이터 제작)

  • Oh, Namsoo;Lee, Haneol;Rodrigue, Hugo
    • The Journal of Korea Robotics Society
    • /
    • v.13 no.2
    • /
    • pp.92-96
    • /
    • 2018
  • In this paper, a soft robotic arm which can prevent impact injury during human-robot interaction is introduced. Two degrees of freedom joint are required to realize free movement of the robotic arm. A robotic joint concept with a single degree of freedom is presented using simple inflatable elements, and then extended to form a robotic joint with two degrees of freedom joint using similar manufacturing methods. The robotic joint with a single degree of freedom has a joint angle of $0^{\circ}$ bending angle when both chamber are inflated at equal pressures and maximum bending angles of $28.4^{\circ}$ and $27.1^{\circ}$ when a single chamber if inflated. The robotic joint with two degrees of freedom also has a bending angle of $0^{\circ}$ in both direction when all three chambers are inflated at equal pressures. When either one or two chambers were pressurized, the robotic joint performed bending towards the uninflated chambers.