Path Force Control for Friction Stir Welding Processes (Preprint)

Abstract

In Friction Stir Welding (FSW) processes, force control can be used to achieve good welding quality. This paper presents the systematic design and implementation of a FSW path force controller. The path force is modeled as a nonlinear function of the FSW process parameters (i.e., plunge depth, tool traverse rate, and tool rotation speed). An equipment model, which includes a communication delay, is constructed to relate the commanded and measured tool rotation speed. Based on the dynamic process and equipment models, a feedback controller for the path force is designed using the Polynomial Pole Placement technique. The controller is implemented in a Smith Predictor-Corrector structure to compensate for the inherent equipment communication delay and the controller parameters are tuned to achieve the best closed loop response possible given equipment limitations. In the path force controller implementation, a constant path force is maintained, even in the presence of gaps, and wormhole generation during the welding process is eliminated by regulating the path force.

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Document Details

Document Type
Technical Report
Publication Date
Feb 01, 2009
Accession Number
ADA502912

Entities

People

  • K. Krishnamurthy
  • Prabhanjana Kalya
  • Robert G. Landers
  • Xin Zhao

Tags

Communities of Interest

  • Sensors
  • Space

DTIC Thesaurus Topics

  • Air Force
  • Air Force Research Laboratories
  • Aluminum Alloys
  • Closed Loop Systems
  • Control Systems
  • Data Acquisition
  • Demographic Cohorts
  • Feedback
  • Frequency
  • Friction
  • Friction Stir Welding
  • Military Research
  • Polynomials
  • Rotation
  • Standards
  • Transfer Functions
  • Welding

Readers

  • Control Systems Engineering.
  • Metallurgy
  • Robotics and Automation.