Design and Analysis of Adaptive PID for Cutting Force Compensation in Ball-Screw Drive System

Chew, Kien Fai (2022) Design and Analysis of Adaptive PID for Cutting Force Compensation in Ball-Screw Drive System. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

As the applications of control systems are diversified due to technology advancement, controllers play an important role in meeting the dire demands. The ball-screw drive system milling machine is subjected to non-linearities and disturbance forces like friction force and cutting force. However, only cutting force is analysed and investigated in this research to find out the best controller to compensate the cutting force. The cutting force induced the vibration during the machining process, which causes tool or workpiece deflection that eventually affect the overall integrity of the final product. Different spindle speeds of 1000rpm, 1500rpm, and 2000rpm of cutting force will be analysed in this thesis to determine their characteristics. The three initial proposal controllers are NPID, non-linear feedforward PID and cascade PID controllers. The construction of NPID controller is necessary prior to the construction of NFPID. The developed controller’s performance is evaluated in terms of tracking error reduction and disturbance rejection. Additionally, the raw data for the cutting force, motor constant, and transfer function of the unidirectional ballscrewdrive control system are derived from prior work, as the thesis is simulation-based and does not include actual plant implementation. In conclusion, NFPID controller has significantly outperforms the other controllers in terms of tracking error reduction and disturbance rejection where the highest improvement of maximum tracking error achieved for NFPID is 13.53 % for 2000 rpm and lowest at 8.72 % for 1000 rpm. Besides, the NFPID controller has effectively decreased the tracking error by a maximum of 42.7 % and a minimum of 42.06 %, respectively. Lastly, the NFPID controller improves cutting force rejection by a maximum of 56.52 % and a minimum of 18.93 %, respectively.