Animatronic C-3PO

[TK-326]

Mechanics - Waist Pivot

In Sept/Oct 2018 I worked through the challenge of building a mechanism to allow the figure to pivot at the waist while carrying pants and the legs with it, to give the illusion that he's turning on his ankles. IMO having the legs pivot with the hips adds so much to the performance and believability of the character. Here's some of the hardware that went into the mechanism.



Waist pivot test - dimensions and linkages will be adjusted to fit the final shell parts based on field measured clearances.

 

[Shanemun]

Very clever design well done

 

[omel]

amazing work so far.!

 

[glottis]

Awesome!

 

[TK-326]

Mechanics - Elbow joint

Working out a mechanical solution for the elbow joint. Considering several options for how to control the motion. I considered the approach of using the actual greeblie pistons on the arms but since I’m going for fast, lifelike movement, my actuators will be quite large and heavy. I’m leaning towards using control cables (bicycle outer casing and inner brake cable) and linkages so I can locate the actuators elsewhere. (Nov 6, 2018)



First prototype done for elbow joint. Now working on mounts and securing the rails into the PLA shells and making them removable for service. Then on to actuators. (Nov 9, 2018)

I later designed and 3D printed some custom spacers for the elbow joint to allow the bicep and forearm shells to be removed independently from the skeleton and mechanism. (Feb 20, 2019)

 

[TK-326]

Mechanics - Waist Pivot (continued)

When you need a custom mounting bracket, you make one. Or two in this case. (Sept 25, 2018)



Time to work out how to mount the servo that will provide the hip swivel motion. (Oct 13, 2018)



Working on a sliding mount to account for belt slack. Drilling and filing out slots for the servo attachment plate to connect. (Oct 13, 2018)

Finished the sliding servo mount for the torso/hip pivot belt drive. Now I need to order a 14” belt since the one I have is too long. (Oct 13, 2018)

Waist pivot motion range test. Servo drive pulley and correct length belt are now installed and tensioned properly. The turntable bearing under this platform will carry the full weight of the animatronic (minus the feet). The pants and legs will hang from mounts on either side, while the torso, arms, and head will stand above the universal joint on top. (Oct 27, 2018)

 

[TK-326]

Mechanics - Waist Pivot (continued)

All mounts are connected, x-rail and pattern plates are trimmed back, and leg hinges are installed. This is as far as I’m going to take the waist pivot mechanics for this phase. Now it’s on to the torso and arms. (Oct 28, 2018)

 

[TK-326]

Mechanism - Neck Platform

Working on the clearances for the neck mechanism so it fits inside the neck ring without constricting the movement of the servos and linkages.

 

[animator]

This is a very exciting project to see progressing so well!

 

[TK-326]

Mechanics - Elbow Limit Switches

Fitting the limit switches that will provide the “home position” signal to the elbow’s motor controller. The motors have quadrature encoders to tell the controller how far they have moved from the home position.

 

[TK-326]

Mechanics - Shoulder and Upper Arm Limit Switches

Shoulder and upper arm rotation “home position” limit switches installed. Still need to fabricate the strike plates that will trigger the switches.

 

[d_jedi1]

Just stumbling across this but this is going to be amazing.
Heck, what already exists of it IS!

 

[TK-326]

Mechanics - Neck Mechanism ("neckanism")

Neck mechanism mounted on torso frame. The mounting solution is temporary until I can design and 3D print a custom one.

 

[TK-326]

Mechanics - Neck Mechanism ("neckanism") continued

Neck mechanism mounted on torso frame with torso shells and neck ring in place. Torso shells have been through the first round of priming and wet sanding.

 

[TK-326]

3D Printed Body Part Shells - Head

Trying to get my head together. The back half has been through one round of priming, spot putty filling, and wet sanding. Several more to go.



The back took about half the time it used to take to print, thanks to the new .08 nozzles.

 

[TK-326]

Mechanics - Elbow Joint

Assembling the worm gear drives that will provide elbow rotation (Feb 18-19, 2018).



Worm gear drives assembled and test fitted into elbow cavity on the arms.



Elbow drive mechanism mounted to upper arm extrusion.

 

[TK-326]

Mechanics - Shoulder Motion

Assembling the fast, high-power linear actuators from GoBilda/ServoCity that will provide the shoulder rotation to lift the arms.



Here’s your first look at the shoulder mechanism that uses the fast-action, high-power linear actuators that I’ve customized for this build. This video shows the shoulder rotation that lifts the arms. Each actuator can provide over 50 pounds of lifting force.

Another look at the shoulder mechanism that uses the fast-action, high-power linear actuators that I’ve customized for this build. This video starts with the shoulder rotation that lifts the arms. Each actuator can provide over 50 pounds of lifting force. The shoulders have another motor with a planetary gearhead to turn the upper arm axially. This is shown later in the video. Each arm will also have a motor for elbow motion. Counting shoulder, elbow, wrist, and fingers, each arm has 10 degrees of freedom.

 

[TK-326]

Mechanics - Shoulder Bearings

I used off-the-shelf 6" lazy susan bearings for the shoulders. The fit inside the 3D printed shoulder on Jesse's torso files was surprisingly almost perfect. Connected them with 1/4-20 threaded rod, later to be sleeved with aluminum extrusion (ServoCity X-Rail). The threaded rod made it easy to make minor adjustments to the spacing, which was necessary since the shoulder rings in the torso aren't perfectly parallel. I also had to grind down one edge of each of the 8 outer nuts so the 3D printed torso shells would fit snugly.

 

[stuwin]

This is fantastic. Do you mind if I copy?

 

[TK-326]

This is fantastic. Do you mind if I copy?

Thanks! Copy?