Noise Reduction for Sub-Nanometer Position Stability in High Dynamic Linear Drives

High accuracy and high acceleration are initially contradictory requirements for servo drives. Especially for production machines in the semiconductor industry, both dynamics and accuracy are particularly important. In this paper, a motion controller for a linear direct drive is optimized as a whole system. The correlation between dynamics and position stability is shown. Due to the availability of inverters based on wide-bandgap semiconductors as well as high-speed analog-to-digital converters with 18 bit resolution, additional options for control loop design exist. A design approach is presented to decrease position noise with high control loop bandwidth. Based on the theoretical considerations, a standstill position stability of 20 pm is achieved on a test stand with a high-dynamic linear drive using a PWM frequency of 100 kHz.     «

High accuracy and high acceleration are initially contradictory requirements for servo drives. Especially for production machines in the semiconductor industry, both dynamics and accuracy are particularly important. In this paper, a motion controller for a linear direct drive is optimized as a whole system. The correlation between dynamics and position stability is shown. Due to the availability of inverters based on wide-bandgap semiconductors as well as high-speed analog-to-digital converters...     »