• Title/Summary/Keyword: Torch Path

Search Result 33, Processing Time 0.025 seconds

A Simple Nonlinear Control of a Two-Wheeled Welding Mobile Robot

  • Bui, Trong-Hieu;Nguyen, Tan-Tien;Chung, Tan-Lam;Kim, Sang-Bong
    • International Journal of Control, Automation, and Systems
    • /
    • v.1 no.1
    • /
    • pp.35-42
    • /
    • 2003
  • This paper proposes a simple, robust, nonlinear controller based on Lyapunov stability for tracking the reference welding path and velocity of a two-wheeled welding mobile robot (WMR). The system has three degrees of freedom including two wheels and one torch slider. Torch slider motion is used for faster tracking because the welding speed is very slow. Control law is obtained from the Lyapunov control function to ensure the asymptotical stability of the system. The controller has three free parameters for adjusting the performance of the controlled system. A simple way of measuring the errors using two potentiometers is introduced. The effectiveness of the proposed controller is shown through simulation results.

A Nonlinear Controller of a Two-Wheeled Welding Mobile Robot Track ing Smooth-Curved Welding Path Using Sliding Mode Control

  • Chung, Tan Lam;Bui, Trong Hieu;Suh, Jin-Ho;Kim, Sang-Bong
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2003.10a
    • /
    • pp.1418-1423
    • /
    • 2003
  • In this paper, a nonlinear controller based on sliding mode control is applied to a two -wheeled Welding Mobile Robot (WMR) to track a smooth-curved welding path at a constant velocity of the welding point. T he mobile robot is considered in terms of dynamics model in Cartesian coordinates and its parameters are exactly known . To obtain the controller, the tracking errors are defined, and the two sliding surfaces are chosen to guarantee that the errors converge to zero asymptotically. Two cases are to be considered: fixed torch and controllable torch. In addition, a simple way of measuring the errors is introduced using two potentiometers. The simulation results are included to illustrate the performance of the control law.

  • PDF

Adaptive Control for Tracking Trajectory of a Two-Wheeled Welding Mobile Robot with Unknown Parameters

  • Bui, Trong Hieu;Chung, Tan-Lam;Suh, Jin-Ho;Kim, Sang-Bong
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2003.10a
    • /
    • pp.191-196
    • /
    • 2003
  • This paper presents a method to design an adaptive controller for the kinematic model of a two-wheeled welding mobile robot (WMR) with unknown parameters. We propose a nonlinear controller based on the Lyapunov function to enhance the tracking properties of the WMR. The WMR can track any smooth curved welding path at a constant velocity of the welding point. The system has three degrees of freedom including two wheels and one torch slider. Torch slider motion is used for fast tracking. To design the tracking performance, the errors from WMR to steel wall is defined, and the controller is designed to drive the errors to zero as fast as possible. The effectiveness of the proposed controller is shown through simulation results.

  • PDF

Sliding Mode Control of Two-Wheeled Welding Mobile Robot for Tracking Smooth Curved Welding Path

  • Chung, Tan-Lam;Bui, Trong-Hieu;Nguyen, Tan-Tien;Kim, Sang-Bong
    • Journal of Mechanical Science and Technology
    • /
    • v.18 no.7
    • /
    • pp.1094-1106
    • /
    • 2004
  • In this paper, a nonlinear controller based on sliding mode control is applied to a two-wheeled Welding Mobile Robot (WMR) to track a smooth curved welding path at a constant velocity of the welding point. The mobile robot is considered in terms of dynamics model in Cartesian coordinates under the presence of external disturbance, and its parameters are exactly known. It is assumed that the disturbance satisfies the matching condition with a known boundary. To obtain the controller, the tracking errors are defined, and the two sliding surfaces are chosen to guarantee that the errors converge to zero asymptotically. Two cases are to be considered: fixed torch and controllable torch. In addition, a simple way of measuring the errors is introduced using two potentiometers. The simulation and experiment on a two-wheeled welding mobile robot are provided to show the effectiveness of the proposed controller.

Mechanism for Vertical Welding for a Combination of Circular and Linear Paths (수직 원호 용접을 위한 메커니즘 구현에 관한 연구)

  • Noh, Tae-Yang;Jang, Won-Tek;Kim, Jae-Kwon;Park, Jong-Yoen
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.35 no.11
    • /
    • pp.1491-1497
    • /
    • 2011
  • One of the primary concerns in the design of welding devices is how to reduce the distance error between the welding path and the torch, especially when the path has a combination of circular and linear parts. This study investigated a mechanism for reducing the tracking error in the tangent area of a circular and linear path. A portable welding device, called a carriage, has been designed for a specific welding path by considering the distance error deviation. This welding carriage for vertical cover plate welding consists of a rail, a welding torch and the carriage body itself.

Numerical Modeling for Systematization of Line Heating Process

  • Shin, Jong-Gye;Kim, Won-Don;Lee, Jang-Hyun
    • Journal of Hydrospace Technology
    • /
    • v.2 no.1
    • /
    • pp.41-54
    • /
    • 1996
  • Sculptured surface structures such as ship hulls are traditionally formed up to the required double curved shape by line heating method. The nature of the line heating process is a transient thermal process, followed by a thermo-elastic-plastic stress field. The permanant shape is dependent on many factors involved in the process, Among them are torch speed and path, supplied heat type and amount , and plate size. Thus, the work is essentially leaded by experts with lots of experiences. However, in order to effectively improve productivity through automation, each factor should be clearly examined how much it affects the final shape. This can not be done only by experiments, but can be achieved by a mechanics-based approach. In this paper, we propose a conceptual configuration for plate forming system, and then present simulations of the line heating process with numerical data in practices and suggest a computerized process of the line heating for practical applications. The modeling of heating torch, water cooling, and the plate to be formed is proposed for the finite element analysis after the mechanics of line heating is studied. Parametric studies are given and discussed for the effects of plate thickness, torch speed and initial curvature in forming a saddle typed surface.

  • PDF

A Study on Automatic Seam Tracking using Vision Sensor (비전센서를 이용한 용접선 자동추적에 관한 연구)

  • 조택동;양상민;전진환
    • Journal of Welding and Joining
    • /
    • v.16 no.6
    • /
    • pp.68-76
    • /
    • 1998
  • A CCD camera with a laser stripe was applied to realized the automatic weld seam tracking. The 3-dimensional information obtained from the vision system made it possible to generate the weld torch path. The adaptive Hough transformation was used to extract laser stripes an to obtain specific weld points. It takes relatively long time to process image on-line control using the basic control using the basic Hough transformation, but it has a tendency of robustness over the noises such as spatter. For this reason, it was complemented with adaptive Hough transformation to have an on-line processing ability for scanning specific weld points. The dead zone, where the sensing of weld line is impossible, was eliminated by rotating the camera with its rotating axis centered at the weld torch. When weld lines were detected, the camera angle was controlled in order to get the minimum image data for sensing of weld lines. Consequently, the image processing time was reduced.

  • PDF

A Study on Automatic Seam Tracking using Vision Sensor (비전센서를 이용한 자동추적장치에 관한 연구)

  • 전진환;조택동;양상민
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1995.10a
    • /
    • pp.1105-1109
    • /
    • 1995
  • A CCD-camera, which is structured with vision system, was used to realize automatic seam-tracking system and 3-D information which is needed to generate torch path, was obtained by using laser-slip beam. To extract laser strip and obtain welding-specific point, Adaptive Hough-transformation was used. Although the basic Hough transformation takes too much time to process image on line, it has a tendency to be robust to the noises as like spatter. For that reson, it was complemented with Adaptive Hough transformation to have an on-line processing ability for scanning a welding-specific point. the dead zone,where the sensing of weld line is impossible, is eliminated by rotating the camera with its rotating axis centered at welding torch. The camera angle is controlled so as to get the minimum image data for the sensing of weld line, hence the image processing time is reduced. The fuzzy controller is adapted to control the camera angle.

  • PDF

A Study on the Pseudoinverse Kinematic Motion Control of 6-Axis Arc Welding Robot (6축 아크 용접 로보트의 의사 역기구학적 동작 제어에 관한 연구)

  • Choi, Jin-Seob;Kim, Dong-Won;Yang, Sung-Mo
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.10 no.2
    • /
    • pp.170-177
    • /
    • 1993
  • In robotic arc welding, the roll (rotation) of the torch about its direction vector does not have any effect on the welding operation. Thus we could use this redundant degree of greedom for the motion control of the robot manipulator. This paper presents an algorithm for the pseudo- inverse kinematic motion control of the 6-axis robot, which utilizes the above mentioned redunancy. The prototype welding operation and the tool path are also graphically simulated. Since the proposed algorithm requires only the position and normal vector of the weldine as an input data, it is useful for the CAD-based off-line programming of the arc welding robot. In addition, it also has the advantages of the redundant manipulator motion control, like singularity avoidance and collision free motion planning, when compared with the other motion control method based on the direct inverse kinematics.

  • PDF

Automatic Nesting and NC Cutting of Flat-Bar (선박용 플랫바의 자동 네스팅 및 가스/플라즈마에 의한 NC 절단)

  • Lee, Cheol-Soo;Park, Gwang-R.
    • IE interfaces
    • /
    • v.9 no.3
    • /
    • pp.283-297
    • /
    • 1996
  • The 'flat-bar' is a stiffener which is a component of ships. It is basically a long rectangle and has 'end-cut' shapes at both sides. The paper describes a fast nesting algorithm of the flat-bar, and a procedure to generate cutting path of gas/plasma torch, which is operated by a NC (numerically controlled) gas/plasma cutting machine. Proposed procedures are written in C-language and executable on VAX machine with Open VMS operating system.

  • PDF