A novel experimental setup for solenoid actuators

We present a novel experimental setup for the analysis of solenoid actuators. Because the main purpose of the experimental setup is the identification and the modeling of different types of solenoid actuators (wide range of possible spool strokes), cost effectiveness and flexibility are key design principles. In solenoid actuators the relevant mechanical quantities are the position (velocity) of the moving part (spool position) and the external load forces. In the proposed setup the position is measured by a reflective optical sensor (photo diode and transistor) with marginal cost and hardware requirement compared to other traditional transducers e.g. inductive sensors. The experimental setup has a vertical configuration and the external load forces are realized by the gravitational force of masses. Thus, the load is exactly known in steady state and does not depend on the spool position; therefore, the force sensors and their hardware are not necessary. Friction associated with the experimental setup is also overcome by the vertical orientation. The test setup is designed in particular consideration of measuring very small spool strokes (~1 mm). The possible error sources which are associated with the measurement of small displacements are also highlighted and reviewed.