AG-HT concept working principle
The technical concept of the first Pre2Pos motor is depicted in the schematics below. Pre2Pos technology is based on the concept of manipulating a flexible ring, which is constrained by 3 fixed pins. The constrains deform the ring inducing the creation of 3 lobes.
How it works
Each lobe is pressed by a linear actuator ( e.g. piezoelectric stack) which is initially set at half stroke (see top schematic ), 3 linear actuators being positioned at equal distances.
By commanding the maximum stroke for actuator 1, the minimum stroke for actuator 2 and leaving the actuator 3 at half stroke, the ring “flows” in the direction indicated by the green arrow.
Then, by continuously commuting the actuators position, the ring is subject to a rotational motion, its speed being determined by the force applied by the linear actuators and their own stroke speeds.
AG-LT concept working principle
The technology behind the second Pre2Pos drive differs deeply from the previous one, but none of its advantages are lost. AG-LT is a resonant piezo-motor that makes use of an hybrid longitudinal-torsional vibration in a fixed stator to drive a rotor through the friction achieved in the resulting intermittent contact between the two components.
How it works
When the stator is pressed against the rotor by its longitudinal vibration mode, a clockwise rotation due to its torsional vibration mode is transmitted from the former to the latter. Before the rotation in the stator can reverse its direction, the stator is detached from the rotor by its compression. The rotor keeps on rotating thanks to its inertia, until the cycle is repeated.
A series of micro angular displacements is achieved at high frequencies, generating a macroscopic rotational movement in the rotor.