Sunday, June 5, 2016

Head Mechanicals

Controlled from within the ball

The head movement pieces will be done from within the main ball area, unlike some builds where there are motors in the dome itself.

Here is a rendering from James Brutan's cad drawings showing the assembly of parts to allow the dome to move around via a magnetized assembly system.




Note, the Green items are made from flexible filament and allow the red items (N52 magnets) to move about as the system pulls it around.  We will review each of these over the next few days, print them and assemble.

You can purchase the N52 magnets on Ebay (only place I could find where these are due to size and scale.  Also you will need 3 NORTH and 3 SOUTH magnets.


Here is a great list of key items for building the GIMBLE and control assembly system

Qty
Part Type and Name
Cost
Where
3
N52 Neodymium Cylinder Magnet 25mm dia x 20mm 6.5mm Hole Counterbore (SOUTH)
30
Used to attach to the head gimble
3
N52 Neodymium Cylinder Magnet 25mm dia x 20mm 6.5mm Hole Counterbore (NORTH)
30
Used to attach to the top of the gimble
1
8mm screw
7.00
Main Axle
2
Flex Printing Drive Wheels


90.00
Total: 200.00
Used for the drive wheels Flex print
4
These bearings are used to hold the 8mm studs in place.


12.22

2
HS 805bb Plus servos
102.00
Used for the Pull/push of the gimble arm
8
4mm screws for assembly of parts


1
HS 564 Hi torque servo

35
Turn the magnets 360'

Lets cover the design

The GIMBLE assembly

The Gimble as he refers to it, is a large assembly that contains:
  • A servo that spins the magnet controls.
  • 2 servos push/pull against it to form a triangle method (delta) movement function moving the dome above on the outside of the ball using very strong magnets (N52).
The main unit will have a cross connection to the main banana's cross bar.



Magnet Assembly (Head)

The NORTH magnets are located round base unit that allows positioning based on slotted openings.  The same green flexible holders are present as well as the magnets this time pointing down to the curvature of the body's ball shape.

Below is a 3D rendering of the magnet assemblies inside and outside of the ball as well as positioning of the wheels for the dome.

Magnet assembly (body)

This is the carrier that holds the SOUTH N52 magnets surrounded by flexible padding that holds the magnets into their sockets allowing some flexible movement as the unit moves against the outer part of the ball inside.



The assembly contains flexible items that provide flex to the magnets, and M8 rod that runs through and into the magnet assembly piece above.



Green Items: Flexible
Red Items: Magnets N52
Blue: Assembly for holding the magnets and connecting to the M8 rod system.