Mitigating non-linear DAC glitches using dither in closed-loop nano-positioning applications
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Original versionA. Faza, J. Leth and A. A. Eielsen, "Mitigating Non-linear DAC Glitches Using Dither in Closed-loop Nano-positioning Applications," 2023 American Control Conference (ACC), San Diego, CA, USA, 2023, pp. 685-691,
Digital-to-analog conversion is essential in digital signal processing applications, including closed-loop control schemes. Noise and distortion in digital-to-analog converters result in reduced performance for high-precision mechatronics such as nano-positioning. Glitches are common in practical switched systems such as digital-to-analog converters; observed as an output disturbance. Due to the wide-bandwidth, impulse-like behavior, control law bandwidth is generally too low to provide adequate attenuation; deteriorating open and closed-loop performance. This article demonstrates how large-amplitude high-frequency periodic dither mitigates the effect of glitches in a nano-positioning system under closed-loop control. Simulations are performed using a model that includes significant non-linearities with a response fitted to an off-the-shelf commercial device, as well as using standard linear time-invariant models for other system components fitted to the responses of common, commercially available devices. The results highlight the significance of reconstruction filter design when applying dithering in this setting.