A high speed, high precision linear drive system for manufacturing automation

High speed and high precision linear motions are found in many industrial applications, such as the wire-bonding and die-bonding of microelectronic components. In order to achieve the tight requirements of future-generation semiconductor packaging machines, a high-performance linear drive system is developed. The linear drive system consists of a Linear Permanent Magnet Synchronous Motors (LPMSM), and a DSP-based fully digital PWM drive. To achieve high trajectory accuracy, a dual-rate multi-loop cascade control structure with velocity and acceleration feed-forward is employed. Also, a velocity observer is used to provide reliable and ripple free feedback information. To increase the current dynamics, overrated momentary high-voltage and high-current are injected to the actuator's coils, through the PWM drive. Finally, to reduce mechanical resonance during the high-speed start-stop operations, a third-order profile generator is developed and employed in the motion path generation process. This paper describes the development of such a linear drive system. The paper includes (i) the construction and modeling of the Permanent Magnet Synchronous Linear Drive; (ii) the simulation of the linear drive and the control system; (iii) the design and hardware implementation of the linear drive system; and (iv) the implementation result. The final result shows that the system is capable of 15G acceleration and 1 micron position accuracy.