An approach to enhancing the intelligence of a three-fingered automated flexible fixturing system by using adaptive control theory

A new approach to clamping workpieces for the machining process has been de veloped. The new approach is based on the identification of the workpiece s tiffness, during the machining process, which enables the fixturing system to determine whether the clamping force should be changed. Using this appro ach, a three-fingered intelligent automated flexible fixturing system for p lanar objects has been successfully designed and implemented. The conventio nal and traditional clamping methods use a hydraulic vise to clamp workpiec es with a fixed amount of clamping forces. This often causes the workpieces to deform under such force, thus contributing to machining error. It is th erefore desirable to control the clamping force according to the progress o f the machining process. The implementation of this approach to the three-f ingered automated flexible fixturing system enhances the system's ability t o achieve intelligent clamping force control and deal with abnormal machini ng, thus making the system intelligent. A thin ring-shaped workpiece was su ccessfully used as an example to demonstrate the feasibility and validity o f this approach. It also demonstrates that the developed system can be used in the highly automated manufacturing system of the future. (C) 1999 Elsev ier Science Ltd. All rights reserved.