Week 14 –
Mechanical Design, Machine Design
Assignment –
mechanical design for final project
For
my final design I need to work out how to move the various parts
of the face, eyes, mouth, and eyebrows, using various servos. To
achieve this I have first to make a prototype face, 3D print the
eyes, buy in the servos, think how to attach and position the
servos, design and make my own servo board so that I can test
the movement of the eyes and mouth.
I
will be using servos and rotary motion for the eyes and eyebrows
and will explore linkages for transferring rotary motion from a
servo motor to linear motion for the mouth to move up and down.
My Workflow this week
To
work on the mechanical design of the final project I first
needed to make the parts and face. I started by drawing up
the eyes in Rhino to appropriate dimensions
Next 3D printed an eye to test dimensions and attached to
servo to check position on back plate of face. Tricky lining
up front and back plate
Attached
eye
to servo motor to see if it fits and shape is suitable. Printed
in black as our only option so will need to source other
colours.
Lasercut
face
and supporting press-fit structure having drawn up design in
Inkscape, first in cardboard, then 3mm ply. Tried various ways
to attach servos.
Designed
my own servo board in Eagle, made, and using my ISP programmed,
now to test the eye
movement on the face
Thought of simple ways to connect the servos so they are secure
and don’t interfere with the design of the face. My concern at
the moment is that they will be heavy so stability of the
structure is paramount. I had originally thought of using a
lightweight press-fit structure to hold the face and this may
need to be reconsidered having tested it! My solution at
the moment is to add a back plate to the face which all the
servos and linkages can be attached using pressfit connectors.
This needs testing.
What next
· Explore linkages
to move the mouth
Position of pivots for eyebrow movement
· Consider best way
to move the mouth and how to attach moving mouth parts to face
· In Inkscape redraw
the back plate of face, position all the press-fit connectors to
hold servos so front and back of face match up
· Remake press-fit
structure to be more stable
· Test
Files for eyes