Ithorian: Head movement

 Another reference image, this one is a min-bust from Gentle Giant

Another reference image, this one is a min-bust from Gentle Giant

Several RL events conspired to throw off my scheduled on the Ithorian costume. A work trip to Australia took 10 days, and then the worst cold I've ever had took another week. Reviewing my schedule, I've finally decide that I'm not going to be able to finish the Ithorian costume before SDCC 2014. I'm sad about it, but it does reduce the pressure and lets me redesign the costume as I run into problems and look for alternatives. Instead, I'll unveil it for the 2015 con season.

However, I'm not stopping work on this. The additional time just lets me make the costume even more awesome! For instance, I've been following the Giant Creature build by Legacy Effects, Stan Winston School, and a variety of partners. This week, they were showing off the mechanical controls the puppeteers will be using inside the creature. That inspired a new mechanical control mechanism for the Ithorian's head. Also, I've gone a bit overboard on images for this part of the build.

Ball joint and mounting hardware

The key components in the mechanism are these ball joints that I bought at a radio-control hobby store. They are used for attaching control surfaces in model airplanes to servo motors. They're solidly built, have smooth movement, and are relatively cheap. I built them into "thrust rods" using threaded rod inside aluminum tubes with a ball joint at each end.

Cutting threaded rod to size

Cleaning up the ends (really, I just wanted to get a shot of grinding steel with sparks flying)

Interrim construction of thrust rods showing ball joints attached to a threaded rod inside an aluminum tube

The steering arm is an aluminum rod passing through a 45 degree PVC joint. The arm has a threaded hole in the middle so that a bolt can hold it in place. Also, the ends are threaded so that the ball joints on the thrust rods are bolted into each end. Here's a more thorough sequence of pictures showing the construction.

My chop saw cuts the aluminum rod to length

Smoothing the edges

Drilling holes in the ends that will be threaded

Clearance hole drilled in the 45 degree PVC connector joint and another clearance hole for the lock down bolt

The ball joint at one end of each thrust rod is screwed into the ends of the steering arm

Sanding down the ends to clean up the rough cut

Drilling the lock down hole that will be threaded

Threading one of the holes with a tap

Lock down bolt screws into the threaded rod locking it on the PVC joint

The steering mechanism is installed so that the left/right axis is mounted into the forward/back axis (shown with the counterbalancing springs)

The drive levers are mounted on each side of my head. They are made from aluminum stock and cut to size for my head. A pivot hole is drilled at one end and used to mount the lever onto the outside of the frame. There's also a threaded hole used to mount the other end of the thrust rods. These are the basic head movement controls.

The lever arms cut to size, a clearance hole at one end and a threaded hole for the thrust rod attachment

The pivot point on the lever arm is loosely bolted to the frame, and the thrust rod is mounted to the lever

Since the lever arms are going to be "attached" to my head, all ends are rounded and deburred

Mechanical assembly is complete, and the lever arms control the neck assembly (left/right and up/down)

A headband loosely attaches to the lever arms so my head motion can drive them. I sewed the basic headband from strips I cut out of an old t-shirt along with some Velcro fasteners, and then I attached EVA form for padding. Some canvas strips are sewed down to wrap around the lever arms. All of this was sewn with our old Necchi sewing machine (sorry, no pictures). That thing is a work horse. At the end, it had to sew through 2 layers of canvas, the EVA foam and two layers of t-shirt material. Tricky, but it got the job done.

Finished headband showing the Velcro fasteners and the padded straps that wrap around the lever arms

The canvas straps on the padding wrap around the lever arms. The arms can move up & down inside the straps and have some room to twist.

The parallelogram structure of the overall mechanism translates my head motion to the head movements of the costume. It's pretty slick. Here are some pictures of me testing the rig. I was checking fit, range of motion, and looking for high friction joints.

The mechanical structure is mounted in the FX corset. The headband is firmly wrapped around my head for controlling the neck/head mechanism.

Checking some range of motion, my head is straight up in this shot. I can tilt my head back and forward as well as turning left and right.

As I bend my head forward and turn, the eyes turn and bend down as well. All the movement is in the neck joints. The eyes themselves are not turning.

I tried to limit my motion to just tilting my head down. The costume head followed pretty well. This isn't the full range. I just couldn't coordinate the shot well.

The rig is comfortable and the range of motion is pretty good. The problem I found was in the azimuth rotation around the neck (left-right). I need to find a lower friction bearing. But overall, I'm very pleased with the movement.

Okay, one last photo. So far I haven't shown the outer structure. I've been making some major changes, so a lot of the foam structures I've previously shown don't fit anymore. Here's what's left of my original foam outer layer on top of the current mechanism. It gives me a feel for the proportions with my head covered. There's lot's of room under that "hump", so my head and all the controls fit comfortably. I'm pretty happy with the overall proportions.

My head will be completely covered, and the rest of the structure has a good profile for an Ithorian.