Friction stir welding (FSW) joins materials by plunging a rotating tool into the work piece. The tool consists of a shoulder and a pin that plastically deforms the parent materials and then forges them together under the applied pressure. To create the pressure needed for forging, a rather large axial force must be maintained on the tool. Maintaining this axial force is challenging for robots due to their limited load capacity and compliant nature. To address this problem, force control has been used, and historically, the force has been controlled by adjusting the plunge depth of the tool into the work piece. This paper develops the use of tool traverse speed as the controlling variable instead of plunge depth. To perform this investigation, a FSW force controller was designed and implemented on a retrofitted Milwaukee Model K milling machine. The closed loop proportional, integral plus derivative (PID) control architecture was tuned using the Ziegler–Nichols method. Results show that the control of axial force via traverse speed is feasible and predictable. The resulting system is more robust and stable when compared with a force controller that uses plunge depth as the controlling variable. A standard deviation of 41.5 N was obtained. This variation is much less when compared with a standard deviation of 129.4 N obtained when using plunge depth. Using various combinations of PID control, the system’s response to step inputs was analyzed. From this analysis, a feed forward transfer function was modeled that describes the machinery and welding environment. From these results, a technique is presented regarding weld seam input energy modulation as a by product of force control via traverse speed. A relative indication of thermal energy in the welding environment is obtained with the feedback of axial force. It is hypothesized that, while under force control, the controller modulates weld seam input energy according to the control signal. The result is constant thermomechanical conditions in the welding environment. It is concluded that the key enablers for force control are the unidirectional behavior and load dynamics of the traverse motor. Larger bandwidths and more stable weld conditions emerge when using traverse speed instead of plunge depth to control the force. Force control of FSW via traverse speed has importance in creating efficient automatic manufacturing operations. The intelligence of the controller naturally selects the most efficient traverse speed.
Skip Nav Destination
e-mail: russ.longhurst@vanderbilt.edu russlonghurst@comcast.net
e-mail: al.strauss@vanderbilt.edu
e-mail: george.e.cook@vanderbilt.edu
Article navigation
July 2010
Research Papers
Enabling Automation of Friction Stir Welding: The Modulation of Weld Seam Input Energy by Traverse Speed Force Control
William R. Longhurst,
William R. Longhurst
Department of Mechanical Engineering, Welding Automation Laboratory,
e-mail: russ.longhurst@vanderbilt.edu russlonghurst@comcast.net
Vanderbilt University
, VU Station B 351592, 2301 Vanderbilt Place, Nashville, TN 37235-1592
Search for other works by this author on:
Alvin M. Strauss,
Alvin M. Strauss
Professor of Mechanical Engineering
Department of Mechanical Engineering, Welding Automation Laboratory,
e-mail: al.strauss@vanderbilt.edu
Vanderbilt University
, VU Station B 351592, 2301 Vanderbilt Place, Nashville, TN 37235-1592
Search for other works by this author on:
George E. Cook
George E. Cook
Associate Dean for Research and Graduate Studies
Department of Mechanical Engineering, Welding Automation Laboratory,
e-mail: george.e.cook@vanderbilt.edu
Vanderbilt University
, VU Station B 351592, 2301 Vanderbilt Place, Nashville, TN 37235-1592
Search for other works by this author on:
William R. Longhurst
Department of Mechanical Engineering, Welding Automation Laboratory,
Vanderbilt University
, VU Station B 351592, 2301 Vanderbilt Place, Nashville, TN 37235-1592e-mail: russ.longhurst@vanderbilt.edu russlonghurst@comcast.net
Alvin M. Strauss
Professor of Mechanical Engineering
Department of Mechanical Engineering, Welding Automation Laboratory,
Vanderbilt University
, VU Station B 351592, 2301 Vanderbilt Place, Nashville, TN 37235-1592e-mail: al.strauss@vanderbilt.edu
George E. Cook
Associate Dean for Research and Graduate Studies
Department of Mechanical Engineering, Welding Automation Laboratory,
Vanderbilt University
, VU Station B 351592, 2301 Vanderbilt Place, Nashville, TN 37235-1592e-mail: george.e.cook@vanderbilt.edu
J. Dyn. Sys., Meas., Control. Jul 2010, 132(4): 041002 (11 pages)
Published Online: June 15, 2010
Article history
Received:
May 28, 2009
Revised:
March 28, 2010
Online:
June 15, 2010
Published:
June 15, 2010
Citation
Longhurst, W. R., Strauss, A. M., and Cook, G. E. (June 15, 2010). "Enabling Automation of Friction Stir Welding: The Modulation of Weld Seam Input Energy by Traverse Speed Force Control." ASME. J. Dyn. Sys., Meas., Control. July 2010; 132(4): 041002. https://doi.org/10.1115/1.4001795
Download citation file:
Get Email Alerts
An Adaptive Sliding-Mode Observer-Based Fuzzy PI Control Method for Temperature Control of Laser Soldering Process
J. Dyn. Sys., Meas., Control
Fault detection of automotive engine system based on Canonical Variate Analysis combined with Bhattacharyya Distance
J. Dyn. Sys., Meas., Control
Multi Combustor Turbine Engine Acceleration Process Control Law Design
J. Dyn. Sys., Meas., Control (July 2025)
Related Articles
Robust Machining Force Control With Process Compensation
J. Manuf. Sci. Eng (August,2003)
The Identification of the Key Enablers for Force Control of Robotic Friction Stir Welding
J. Manuf. Sci. Eng (June,2011)
Design and Implementation of Nonlinear Force Controllers for Friction Stir Welding Processes
J. Manuf. Sci. Eng (December,2008)
Formability Enhancement for Tailor-Welded Blanks Using Blank Holding Force Control
J. Manuf. Sci. Eng (August,2003)
Related Proceedings Papers
Related Chapters
Historical Overview
History of Line Pipe Manufacturing in North America
Design a Hybrid Machine Tool for Plane Curve Friction Stir Welding
International Conference on Mechanical Engineering and Technology (ICMET-London 2011)
Development of Mathematical Model for Friction Stir Welding of 304L Stainless Steel
International Conference on Mechanical and Electrical Technology 2009 (ICMET 2009)