Proposed solution: Combine power and speed advantages of stepper motors with feedback advantages of servomotors. Use hybrid stepmotor and driver package to eliminate missed steps and provide closed-loop system reliability.
Selection criteria:
• Two-phase stepper motor delivers speed and precision, but feedback device constantly monitors motor shaft to detect and correct for loss of synchronism.
• Closed-loop control only comes into play when a position deviation of 1.8° or higher is detected.
Enabling technology: AlphaStep Series stepping motor and driver package from Oriental Motor USA Corp., Torrance, Calif.
Design in action: The system works like a large XYZ plotter, with one AlphaStep motor on the Y and Z axes, and two on the X. Using CNC technology, the machine cuts wood and plywood to make furniture, signs, musical instruments, crafts, and boats.