• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.293-298
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• 2005

The purpose of this study was the development of a multi-joint robot manipulator for milking robot system. The multi-joint robot manipulator was controlled by 5 drivers with driver controller through the position information obtained from the image processing system. The robot manipulator to automatically attach each teat cup to the teats of a milking cow was developed and it's motion was accurately measured with error rate. Results were as follows. 1. Maximum errors in position accuracy were 4mm along X-axis, 4.5mm along Y-axis and 0.9mm along Z-axis. Absolute distance errors were maximum 4.8mm, minimum 2.7mm, and average 3.6mm. 2. Errors of repeatability were maximum 3.0mm along X-axis, 3.0mm along Y-axis, and 0.5mm along Z-axis. Distance error values were maximum 3.2mm, minimum 2.2mm, and average 2.5mm. It is envisaged that multi-joint robot manipulator can be applicate to milking robot system being developed in consideration of the experiment results.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.5
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• pp.506-509
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• 2012

Laser assisted machining is the processing method that preheating brittle materials by laser heat source and cutting the soften area. This processing applied to various industries because it can be cutting difficult-to-cut materials. However, the laser assisted machining appeared the limitations of processing for equipped with the spindle. So, it assumed separate model that spindle and laser assisted machining. In feed, the calculation of changing the angle of the laser module according to preheat point and the shape of the feed is important and it tried easy calculating changing angle of 1-axis Manipulator in separate model. In 3 types feed shape, angle of 1-axis Manipulator was calculated when fixed and moved in the outside of spindle. In this study, suggest 2 types of methods for laser module when fixed and moved.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.3
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• pp.84-92
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• 2014

In this paper, a novel 5-axis hybrid-kinematic machine tool is introduced and the research results on accuracy improvement of the prototype machine tool are presented. The 5-axis hybrid machine tool is made up of a 3-DOF parallel manipulator and a 2-DOF serial one connected in series. The machine tool maintains high ratio of stiffness to mass due to the parallel structure and high orientation capability due to the serial-type wrist. In order to acquire high accuracy, the methodology of measuring the output shafts by additional sensors instead of using encoder outputs at the motor shafts is proposed. In the kinematic view point, the hybrid manipulator reduces to a serial one, if the passive joints in the U-P serial chain at the center of the parallel manipulator are directly measured by additional sensors. Using the method of successive screw displacements, the kinematic error model is derived. Since a ball-bar is less expensive than a full position measurement device and sufficiently accurate for calibration, the kinematic calibration method of using a ball-bar is presented. The effectiveness of the calibration method has been verified through the simulations. Finally, the calibration experiment shows that the position accuracy of the prototype machine tool has been improved from 153 to $86{\mu}m$.

• Journal of Biosystems Engineering
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• v.26 no.2
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• pp.163-168
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• 2001

A manipulator for test-cup attachment modules, which was a part of a robot milking system, was developed to reduce cost and labor for cow milking processing. A Cartesian coordinate manipulator was designed for the milking process, because it was quite flexible and can be constructed more economically than any other configuration. The manipulator was made use of DC motors, screws for power transmission, a RS422 interface system for the transmission of coordinate values and a one-chip microprocessor, 89C52. Performance tests of the manipulator were conducted to measure experimentally the precision of all axes. Some of the results are as follows. 1. The Cartesian coordinate manipulator was designed and built. Dimension of the three perpendicular axes (X, Y, and Z) and one arm’s axis(W) to pick up and transfer the modules were 700㎜$\times$450㎜$\times$550㎜$\times$650㎜. The arm’s axis moved the teat-cup attachment module, which attached four teat-cup to four teats, detached four teat-cup from four teats, was designed and manufactured by using CAD, CAM and CNC. 3. After 10 replications of exercising the manipulator, mean precision values(positioning error) of X, Y, Z axes wee 0.48㎜, 0.20㎜, 0.19㎜, respectively. Therefore, we conclude the axes to have a precision better than 0.5㎜, had no problem to operate correctly the milking manipulator.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.968-973
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• 1991

Seven axis modular type pneumatic manipulator is composed of electro-pneumatic automation system which contributes to factory automation by performing loading & unloading process successively which is simple routine work of dealing item of machine tool, catapult, assembly machine, welding machine and so on. In this study, we obtained soft and quick movement in a large space and good reliability motion of various function by combining several actuators which perform rotation movement as well as linear movement at the same time. Gripper which apply to rotary sensor transmitted a structure to demanded position. This development item of 5kgf load prevent stick-slip phenomena of stroke end by designing high cushion internal. We develope flexible manipulator which conforms to demand of user by applying multiple sequence program.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.680-688
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• 2005

This paper presents a methodology for the stiffness analysis of a low-DOF parallel manipulator. A low-DOF parallel manipulator is a spatial parallel manipulator which has less than six degrees of freedom. The reciprocal screws of actuations and constraints in each leg can be determined by making use of the theory of reciprocal screws, which provide information about reaction forces due to actuations and constraints. When pure farce is applied to a leg, the leg stiffness is modeled as a linear spring along the line. For pure couple, it is modeled as a rotational spring about the axis. It is shown that the stiffness model of an it_DOF parallel nipulator consists of F springs related to actuations and 6-F springs related to constraints connected from the moving platform to the base in parallel. The 6x f Cartesian stiffness matrix is derived, which is the sum of the Cartesian stiffness matrices of actuations and constraints. Finally, the 3-UPU, 3-PRRR, and Tricept parallel manipulators are used as examples to demonstrate the methodology.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.5
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• pp.76-82
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• 1999

During operating given working a robot manipulator makes some problems such as the accumulation of the error or the deviation from the command trajectory. These problems are mainly due to the disturbance noise or unmodeled system parameters. To solve these problems most of robot manipulators equip the controller. But if exact controller gains are not seleced we can't decrease the working efficiency(such as compensation about error or deviation) of the robot manipulator. So in this paper we present the controller gain tuning law by which we can find the controller gain which satisfies the per-formance specification of the robot manipulator during working of the robot. The proposed algorithm is derived from the Laypunov direct method. And by the simulation on the 4-axis SCARA type robot(SAMSUNG SM5 Robot) we guarantee the performance of this algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.539-546
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• 2004

Conventional robot manipulators actuated by motors with the speed reducer such as the harmonic drive have weakness in the load capacity, since the speed reducer does not have enough strength. To overcome this, a new type of the robot actuator based on the four-bar-link mechanism driven by the ball screw was proposed and constructed. Also, a new type of a revolute-jointed robot manipulator composed of the developed actuators was developed. The base axis is actuated by the motor with the conventional speed reducer, but the other axes are actuated by the proposed actuators. The kinematics and dynamics of the robot were analyzed, and the performance test of the robot was made. Through the test results, the performance of superior load capacity versus the robot weight is shown.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.89-96
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• 2015

In this paper, it is studied that kinematic analysis of a 5-axis ultrasonic inspection equipment. The equipment is comprised of three straight axes and two rotary axes. With features of ultrasonic, the transmitter and receiver of the equipment are vertical to a test surface, operating at regular intervals. To perform this well, the motions of every link should be found on the based of kinematic analysis of the equipment. We chose starting point for testing and defined relations among all links through transformation of coordinates. For double curvature-shaped test object, we generated test paths. To follow these, we found motions of all links using inverse kinematics. By using Matlab/Simulink, simulator was developed, so that we could find out desired trajectories of main axes for a scan.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.103-108
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• 2005

Loading/Unloading task in the real industry is performed by crane, but most of the loading/unloading task with the weight of 5kg∼30kg is done by human workers and this kind of work causes industrial disaster of workers. Therefore it is necessary to develop low cost loading/unloading manipulator system to prevent this kind of industrial accidents. This paper is concerned with the design and fabrication of 2 axis pneumatic manipulators using on/off solenoid valves and accurate position control without respect to the external load and low damping in the pneumatic rotary actuator. To overcome the change of external load, switching of control parameter using LVQNN (Learning Vector Quantization Neural Network) is newly applied, which estimates the external loads in the pneumatic cylinder. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied to the switching control system. The effectiveness of the proposed control algorithms are demonstrated through experiments of pneumatic cylinder with various loads.