The stage moves! (Mechanics update 5)

Cad design drawn. Laser cutter sorted. Acrylic glued. Piezo buzzers mounted and connected electrically. All really exciting. Look how the stage has progressed over these weeks;

Early stage iterations
Early stage iterations
Testing the electrical contacts on the new stage
New Stage

We have made a new stage and connected it up to a function generator. This meant that we could apply a varying voltage across the piezo buzzers. (Piezoelectric materials physically deform when a voltage is applied across them). By applying a time varying voltage we generate time varying motion in the buzzers and by gluing our stage to the buzzers move our stage.

Here is a video showing our stage moving with the function generator. It isn’t that exciting but does confirm that the stage is moving and can be controlled electrically.   

We took the film using a USB microscope which is pretty hard to calibrate so whilst we know the stage is moving we haven’t yet worked out how far.

We are currently running some finite element simulations to understand the precise motion of the stage. We need to quantify the scanning motion and compare that to the vertical motion generated by the set up.

UPDATE: Finite element simulations have started to come through. We started pretty simple just looking at the deflection of a single piece of the stage. We can see the deflection pretty clearly and also using the simulations can investigate how the piezo displacement affects the in plane motion (x and y) and the out of plane motion (z).

Simulation of stage motion
Simulation of stage motion

We want to have motion in only one of x, y and z although we expect the stage will couple in plane and out of plane motion. Most important is that the in plane motion is greater than the out of plane motion. The simulations only include one leg moving up (as it is easier to simulate) rather than one leg moving up as the other leg moves down. Physically this is the same thing however it will exaggerate out of plane motion. Here is our data – we think it looks promising. Also it is all linear which is really great as it makes accounting for stage motion simple.

Graph showing displacements along three principle directions.
Graph showing displacements along three principle directions.