High precision linear slide. Part II: Control and measurements

Design and construction of a linear slide have been discussed in Mekid. Very high precision in nanometric scale depends on mechanical design and servo control with a very precise and adequate metrology. However, servo technology is employed as a method for going beyond mechanical accuracy limits. For that purpose the linear slide is controlled using two methods: Proportional-Integral-Derivative (PID) controller and Internal Model Controller (IMC) that would compensate automatically for unmodeled mechanical behaviors such as prerolling phenomena. The paper focuses on the design of a numerical controller able to handle imprecision in the model of behavior of mechanical and electromechanical components of the bench. The metrology frame including laser interferometer and optic linear encoder was used for the measurements.