Experimental comparison of dynamic FEA results of a permanent magnet brushless DC linear motor

The dynamic behaviour of a permanent magnet brushless DC linear motor (PMBDCLM) is determined to provide the operating potential when applied as a computer numerical control (CNC) feed drive for material removal purposes. Dynamic analysis results are utilized to provide a machine operator interface for milling operating parameters. The five key analyses included here are: (1) the motor slide position versus time and input voltage variants; (2) the velocity of the motor slide versus input voltage variants, (3) the acceleration of the motor slide versus input voltage variants, (4) the normal force versus current density variants under different input voltages, and (5) the development of a user interface providing operating parameters based on FEA results. Preliminary tests were conducted on a BR12-33 DC linear motor model with different input voltages and normal loads. Further tests were conducted on a PMBDCLM-equipped vertical milling machine. The data acquisition system included a digital encoder attached to the motor slide for detecting position and velocity data, a microprocessor board, software, and a microcomputer. Cutting force data were recorded using a force transducer, amplifier, and an A/D board. The solutions, which are obtained from simulation by a finite element analysis (FEA) dynamic module of EMRC-NISA software, provide the data necessary for comparison of experimental results, and are applied to justify feed-rate values. In addition, results obtained are useful in the selection criteria of operating parameters.