• Title/Summary/Keyword: Constant Velocity Joint

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로봇의 최적 시간 제어에 관한 연구

  • 정년수;한창수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.10a
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    • pp.301-305
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    • 2001
  • Conventionally, robot control algorithms are divided into two stages, namely, path or trajectory planning and path tracking(or path control). This division has been adopted mainly as a means of alleviating difficulties in dealing with complex, complex, coupled manipulator dynamics. The minimum-time manipulator control problem is solved for the case when the path is specified and the actuator torque limitations are known. In path planning, DP is applied to applied to find the shortest path form initial position to final position with the assumptions that there is no obstacle and that each path is straight line. In path control, the phase plane technique is applied to the minimum-time control with the assumptions that the bound on each actuator torque is a function of joint position and velocity or constant. This algorithm can be used for any manipulator that has rigid link, known dynamics equations of motion, and joint angles that can be determined at a given position on the path.

Inverse Kinematic and Dynamic Analyses of 6-DOF PUS Type parallel Manipulators

  • Kim, Jong-Phil;Jeha Ryu
    • Journal of Mechanical Science and Technology
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    • v.16 no.1
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    • pp.13-23
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    • 2002
  • This paper presents inverse kinematic and dynamic analyses of HexaSlide type six degree-of-freedom parallel manipulators. The HexaSlide type parallel manipulators (HSM) can be characterized as an architecture with constant link lengths that are attached to moving sliders on the ground and to a mobile platform. In the inverse kinematic analyses, the slider and link motion (position, velocity, and acceleration) is computed given the desired mobile platform motion. Based on the inverse kinematic analysis, in order to compute the required actuator forces given the desired platform motion, inverse dynamic equations of motion of a parallel manipulator is derived by the Newton-Euler approach. In this derivation, the joint friction as well as all link inertia are included. Relative importance of the link inertia and joint frictions on the computed torque is investigated by computer simulations. It is expected that the inverse kinematic and dynamic equations can be used in the computed torque control and model-based adaptive control strategies.

Cold Forging Technology of large-sized and complicated parts (대형 난성형 부품의 냉간단조기술)

  • 이영선;김영광;이정환;정형식;김영수
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.06a
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    • pp.135-144
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    • 1995
  • Cold Forging has advantage in high accuracy and short working time. However large-skzed and complicated parts are difficult to process with cold forging. Thus large-sized and complicated parts have been processed with two pieces, or combind forging that is hot forging in addition to cold sizing. Recently, large-sized and complicated parts can be manufactured with cold forging alone by advanced cold forging technology using the long-stroke press. In this paper, cold forging technology of large-sized and complicated parts are investigated, including tripod slide housing for constant velocity joint and drive shaft for starter.

Design of the Cold Forging Process for the Outer Race of BJ Type Constant Velocity Joint using Plasticine (플라스티신을 이용한 BJ형 등속죠인트 외륜의 냉간단조공정설계)

  • 이정환;이영선;박종진
    • Transactions of Materials Processing
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    • v.3 no.3
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    • pp.282-290
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    • 1994
  • The outer race of BJ type C.V.Joint has a complicated shape and ball grooves. It is produced by cold or warm precision forging. Especially, the precision level of the ball grooves determines the quality of the part. The objective of the present study is to develop process conditions of the cold forging using the plasticine. Because the cold forging consists of forward extrusion, upsetting, backward extrusion and cold sizing, the study was focused on finding the best perform for each process. The data obtained from the study will be used in the design of the cold forging process for the outer race.

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In-situ Crack Propagation Observation of a Particle Reinforced Polymer Composite Using the Double Cleavage Drilled Compression Specimens

  • Lee Yeon-Soo;Yoon Young-Ki;Jeong Bo-Young;Yoon Hi-Seak
    • Journal of Mechanical Science and Technology
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    • v.20 no.3
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    • pp.310-318
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    • 2006
  • In this study, we investigate the feasibility of in-situ crack propagation by using a double cleavage drilled compression (DCDC) specimen showing a slow crack velocity down to 0.03 mm/s under 0.01 mm/s of displacement control. Finite element analysis predicted that the DCDC specimens would show at least 4.3 fold delayed crack initiation time than conventional tensile fracture specimens under a constant loading speed. Using DCDC specimens, we were able to observe the in-situ crack propagation process in a particle reinforced transparent polymer composite. Our results confirmed that the DCDC specimen would be a good candidate for the in-situ observation of the behavior of particle reinforced composites with slow crack velocity, such as the self-healing process of micro-particle reinforced composites.

Development of web based shape inspection system for the forging products having complicated shapes (인터넷을 이용한 정밀단조품의 품질평가 시스템 개발에 관한 연구)

  • Park, K.S.;Kim, B.J.;Jang, J.H.;Moon, Y.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.211-214
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    • 2006
  • The outer race of the constant velocity(CV) joint is an important load-supporting automotive part, which transmits torque between the transmission and the wheel. The outer race is difficult to forge, because its shape is very complex and the required dimensional tolerances are very stringent. Therefore, the internet based shape inspection system is developed in this study to provide quick and accurate data through the easy control from users. Proposed system uses mechanical displacement sensors to measure the shape of CV joint that has six inner ball grooves, and commercially available Lab-View program is used to process measured data into the dimensional shape. Developed program provides a simple user interface that enables users real-time access of data measured from industrial production lines. Furthermore, it can exchange measured data via the internet between users and forging system operators. A java applet helped the system connection via internet. A data, IP access, is transmitted to the packet by TCP/IP. Our proposed system has many advantages over current measuring systems including fast and efficient data processing by real-time control, and system flexibility.

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Experimental Study on Multi-Stage Cold Forging for an Outer Race of a CV Joint (등속조인트용 외륜의 다단 냉간 단조공정에 관한 실험적 연구)

  • Kang, B.S.;Ku, T.W.
    • Transactions of Materials Processing
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    • v.23 no.4
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    • pp.221-230
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    • 2014
  • This study deals with a series of experimental investigations on multi-stage cold forging of an outer race used for a constant velocity (CV) joint with six inner ball grooves. The multi-stage cold forging, which consists of forward extrusion, upsetting, backward extrusion, and combined sizing-necking including ironing, was used to produce a prototype of the outer race. The cold forging tools such as forging punches and dies required in this multi-stage cold forging were also designed and fabricated. For the combined sizing-necking, especially, the longitudinally six-segmentallized punches were developed to easily eject from the necked inner groove of the outer race with consideration of the operating mechanism. Spheroidized SCr420H billet was used in the experimental study. To verify the suitability of the proposed process, the obtained parts were obtained from each forging operation, and the geometries were compared with the target dimensions. It was confirmed that the outer race with six inner ball grooves was well forged by adopting the proposed multi-stage cold forging, and the dimensional accuracy of the forged outer race matched well with the requirements.

Process Modification and Numerical Simulation for an Outer Race of a CV Joint using Multi-Stage Cold Forging (등속조인트용 외륜의 다단 냉간 단조공정을 위한 공정개선 및 유한요소 해석)

  • Kang, B.S.;Ku, T.W.
    • Transactions of Materials Processing
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    • v.23 no.4
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    • pp.211-220
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    • 2014
  • The outer race of a constant velocity (CV) joint having six inner ball grooves has traditionally been manufactured by multi-stage warm forging, which includes forward extrusion, upsetting, backward extrusions, necking, ironing and sizing, and machining. In the current study, a multi-stage cold forging process is examined and an assessment for replacing and modifying the conventional multi-stage warm forging is made. The proposed procedure is simplified to the backward extrusion of the conventional process, and the sizing and necking are combined into a single sizing-necking step. Thus, the forging surface of the six ball grooves can be obtained without additional machining. To verify the suitability of the proposed process, a 3-dimensional numerical simulation on each operation was performed. The forging loads were also predicted. In addition, a structural integrity evaluation for the tools was carried out. Based on the results, it is shown that the dimensional requirements of the outer race can be well met.

Shear Behavior of Rough Granite Joints Under CNS Conditions (일정 수직강성 조건하 화강암 인장절리의 전단거동 특성)

  • Park, Byung-Ki;Lee, Chang-Soo;Jeon, Seok-Won
    • Tunnel and Underground Space
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    • v.17 no.3 s.68
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    • pp.203-215
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    • 2007
  • Stability and mechanical deformation behavior of rock masses are highly dependent on the mechanical characteristics of contained discontinuities. Therefore, mechanical characteristics of the discontinuities should be considered in the design of tunnel and underground structures. In this study, direct shear tests for rough granite joints were carried out under constant normal stiffness conditions. Effects of initial normal stress, shear velocity, and surface roughness on the characteristics of shear strength and deformation behaviors were examined. Results of shear testing under constant normal stiffness conditions reveal that shear behaviors could be classified into two categories, based on the amount of decrease in shear stress at the Int peak shear stress. With initial normal stiffness increasing, it turned out that shear displacement at peak stress and the first peak shear stress increased, however friction angle and friction coefficient showed decrease. In case of shear stiffness and average friction coefficient, it turned out that they are not dependent on the initial normal stress. Minor effects of shear velocity on rough joints were observed in several shear quantities. However, the effects of shear velocity were insignificant regardless of the normal stress increase. Change of shear strength and deformation characteristics on joint roughness were examined, however, it turned out that the variations were attributed to deviation of shear test specimens.

Adaptation of Motion Capture Data of Human Arms to a Humanoid Robot Using Optimization

  • Kim, Chang-Hwan;Kim, Do-Ik
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2126-2131
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    • 2005
  • Interactions of a humanoid with a human are important, when the humanoid is requested to provide people with human-friendly services in unknown or uncertain environment. Such interactions may require more complicated and human-like behaviors from the humanoid. In this work the arm motions of a human are discussed as the early stage of human motion imitation by a humanoid. A motion capture system is used to obtain human-friendly arm motions as references. However the captured motions may not be applied directly to the humanoid, since the differences in geometric or dynamics aspects as length, mass, degrees of freedom, and kinematics and dynamics capabilities exist between the humanoid and the human. To overcome this difficulty a method to adapt captured motions to a humanoid is developed. The geometric difference in the arm length is resolved by scaling the arm length of the humanoid with a constant. Using the scaled geometry of the humanoid the imitation of actor's arm motions is achieved by solving an inverse kinematics problem formulated using optimization. The errors between the captured trajectories of actor arms and the approximated trajectories of humanoid arms are minimized. Such dynamics capabilities of the joint motors as limits of joint position, velocity and acceleration are also imposed on the optimization problem. Two motions of one hand waiving and performing a statement in sign language are imitated by a humanoid through dynamics simulation.

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