Resumen de Development of a novel pneumatic positioning actuator equipped with new continuous air impulse generators
Ali Radhi, Kamran Behdinan, Vincent Iacobellis
In this study, an innovative pneumatic positioning actuator is developed and tested. Furthermore, two novel mechanisms of crank-swinging lever and cam-follower that generate controlled air impulses are proposed, simulated in MSC.visualNastran software, and fabricated. The pneumatic actuator moves due to the recoil of an internally shot bullet. The bullet returns to its original place after one impact thanks to springs. The actuator and the base have a friction force that prevents hysteresis after each full forward movement. The recoil force is larger than the friction force, which causes the actuator to move. Meanwhile, since the spring force is smaller than the friction force, there is no movement during the return of the bullet. FLUENT and COMSOL software are employed to numerically study the proposed model and optimize the dimensions of the actuator. The problem consists of two components; solid mechanics and fluid-solid interface physics. The piston itself moves in a solid mechanic environment, and the air interaction and flow is related to laminar flow. Using the optimization part in Comsol, the parametric values of the proposed geometry are optimized. It is shown that the simulated device can provide repeatable displacements of 10 nm. The accuracy depends upon the magnitude of the air impact and the fabrication’s specifications and could decrease up to a few micrometers in each step. Repeating the steps gives a continuous stepped movement. Furthermore, the actuator moves in two directions using positive pressure or suction. The fabricated device can reach the positioning accuracy aimed in simulations.
