Patent ID: 8052034

Claim:
A friction stir method for processing at least one workpiece, wherein a system for said method comprises a spindle actuator coupled to a rotary tool comprising a rotating member for contacting and processing said at least one workpiece, the method comprising: oscillating the rotary tool laterally with respect to a selected propagation path for the rotating member with respect to the one workpiece to define an oscillation path for the rotating member; obtaining one or more force signals or parameters related to said force experienced by said rotary tool at least while the rotating member is disposed at first and second extremes of said oscillation of the rotary tool; comparing said force signals or parameters associated with the first extreme and said force signals or parameters associated with second extreme to stored lateral position correlation data to determine a lateral position of the selected propagation path with respect to a target path for the at least one workpiece; and determining a lateral offset value based on said lateral position and decreasing a lateral distance between the selected propagation path and the target path based on the lateral offset value.