Thermal error modeling and compensation of long-travel nanopositioning stage

Thermally induced error of nanopositioning systems is rarely studied specifically because most researchers strictly limit the ambient temperature in order to ignore the influences of thermal deformation. However, the control cost of a narrow temperature range is too high for widely application. This paper is addressed at modeling and compensation of thermal error with the purpose of ensuring the positioning accuracy with an extended temperature range. The finite element analysis and contrast experiments with different temperature ranges reveal the significant impact of temperature variation on positioning precision. A polynomial model based on the genetic algorithm is implemented to describe the relationship between deviations and temperatures. By utilizing the parametric study, the optimal parameters of the genetic algorithm are determined. Based on the thermal model, a compensation system has been developed. A constant proportional–integral–derivative (PID) controller and a single-neuron PID controller are employed for compensation, respectively. The results demonstrate that the single-neuron PID controller can effectively restrain thermal error and guarantee the location accuracy with extended temperature range. The positioning precision of the positioning stage with compensation system and temperature range of 20 + 0.3°C is improved to 12 nm, while the one of the original system with temperature range of 20 ± 0.01°C is 31 nm.