• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.2
• /
• pp.146-158
• /
• 1996

This paper develops a robot arm for propeller blade grinding. The grinding work requires a high stiffness robot arm to reduce deformation and vibration which are generated during machining operation. Conventional articulated robots have serial connecting links from the base to the gripper. Thus, they have very weak structure to the stiffness for grinding operation. Stewart Platform is a typical parallel robotic mechanism with very high stiffness but it has small work space and large installation space. This research proposes a new grinding robot arm by combining parallel mechanism with serial mechanism. Therefore, the robot has large range of work space as well as high stiffness. This paper introduces the automatic system for propeller grinding utilizing the robot and the design of proposed robot arm.

• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.9
• /
• pp.952-958
• /
• 2009

This article presents a combined structure of serial and parallel mechanisms for a humanoid robot. The 3 DOF parallel structure is designed and added to the waist of the humanoid robot arm to give flexible bending and rotating motions. Forward and inverse kinematics of a serial and parallel robot have been analyzed to generate motions. Simulation studies of verifying kinematics solutions of the parallel robot have been done. Experimental studies of mimicking shake-hands motion have been conducted to show the feasibility and usability of the combined structure.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.621-625
• /
• 2005

This paper presents a new hybrid serial-parallel robot(HSPR), which has six degrees of freedom driven by ball screw linear actuators and motored joints. This hybrid robot design presents a compromise between high rigidity of fully parallel manipulators and extended workspace of serial manipulators. The hybrid robot has a large, singularity-free workspace and high stiffness. Therefore, the presented kinematic structure of the hybrid robot is particularly suitable for multi-tasking machining processes such as milling, drilling, deburring and grinding. In addition to the machining processes, the hybrid robot can be used for welding, fixturing, material handling and so on. The study on design of the hybrid robot is performed. A kinematic analysis and mechanism description of the hybrid robot with six-controlled degree of freedom is presented. In the virtual design works by DADS, workspace and force analysis are discussed. A numerical model is treated to demonstrate our analysis and to determine the range of permissible extension of the struts. Also, we determine some important design parameters for the hybrid robot.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1722-1723
• /
• 2007

This paper describes a simple method to reduce rotation angle error of mobile robot using omni-wheel[3](omni-bot). This method can be applied to not only omni-bot, but also other robot with a large number of servo motor. Robot using many servo motor as omni-bot is complicated for hardware and software, each servo motor has difficulty in synchronizing. Three servo motor, three omni-wheel and three serial servo motor controller is used, PC or Micro Processor interface with the serial servo controller through "SSC100" protocol. In order to check the improvement of the proposed serial servo synchronization compared to existing sequential communication method. comparing object is rotation angle error of omni-bot. The results of this make building of omni-bot system easy and decrease rotation angle error.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.10a
• /
• pp.143-144
• /
• 2009

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.4
• /
• pp.320-328
• /
• 2007

This paper presents a stiffness modeling of a low-DOF parallel robot, which takes into account of elastic deformations of joints and links, A low-DOF parallel robot is defined as a spatial parallel robot which has less than six degrees of freedom. Differently from serial chains in a full 6-DOF parallel robot, some of those in a low-DOF parallel robot may be subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each serial chain can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness of an F-DOF parallel robot can be modeled such that the moving platform is supported by 6 springs related to the reciprocal screws of actuations (F) and constraints (6-F). A general $6{\times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints, The compliance of each spring can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; a link is modeled as an Euler beam and the compliance matrix of rotational or prismatic joint is modeled as a $6{\times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is infinite. By summing joint and link compliance matrices with respect to a reference frame and applying unit reciprocal screw to the resulting compliance matrix of a serial chain, the compliance of a spring is determined by the resulting infinitesimal displacement. In order to illustrate this methodology, the stiffness of a Tricept parallel robot has been analyzed. Finally, a numerical example of the optimal design to maximize stiffness in a specified box-shape workspace is presented.

• KEPCO Journal on Electric Power and Energy
• /
• v.2 no.4
• /
• pp.609-613
• /
• 2016

A hybrid charging method with serial and parallel architecture has been developed to resolve the unbalanced charge problem among battery cells for Electric Vehicles. In this method, the major charging is performed with serial part and the balancing is carried out with the parallel part, where the serial part is big and heavy but the parallel part is smaller and lighter than serial part. A sensor array to detect the individual battery cell voltage, duty rate control incorporated IGBTs, and battery management system are employed as the core parts of the proposed system.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1396-1401
• /
• 2004

In recent years, robot has been used widely in industrial field and has been expanded as a result of continous research and development for high-speed and miniaturization. The goal of this paper is to design the special serial manipulator through the understanding of the structure, mobility, and analysis of serial manipulator. Thereafter we control the position and orientation of end-effector with respect to time. In general, a structure of industrial robot consists of several links connected in series by various types of joints. Typically revolute and prismatic joints. The movement of these joints is determined in inverse kinematic analysis. Compared to the complicated structure of parallel and hybrid robot, open loop system retains the characteristic that each link is independent and is controlled easily by AC servomotor that is used to place the robot end-effector toward the accurate point with the desired speed and power while it is operated by position control algorithm. The robot end-effector should trace the given trajectory within the appropriate time. The trajectory of 3D end-effector model made by OpenGL can be displayed on the monitor program simultaneously

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.575-581
• /
• 1993

This paper deals with analysis of articulated robot manipulator used for Arc welding and Material handling. Compared with present robot of which weight holding capacity is 6kg, this robot shows wider and symmetric working range for it's serial type mechanism. The link length is determined to have widest working range by using optimal simulation. To reduce body's weight, small AC servo motor is adopted and driving peak torque exerted at each joint is reduced by using dynamic analysis. So it is possible to reduce body's weight by 40% compared with the same class's robot and get wider working range. And by adopting modular design concept, each axis is designed to be changed easily for user's special need and repair.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.11a
• /
• pp.485-486
• /
• 2008