This week, I finished creating a first body model in Solidworks. This model has slots in the rear to accommodate the four control motors, as well as a groove in the front where I will be able to attach the ears. I was hoping to attach an additional groove to the rear section of the model, but was not able to create it in Solidworks before the end of the week, and wanted to have a print ready before our week long break.

I’m not super happy with the shape I ended up with, since it doesn’t look very natural. Given the time restraints though, I think it will be important to print this body now and learn from my mistakes so that a future body will (hopefully) look more natural and compelling, and have a more thought out internal mechanism.

Before beginning with the 3D modelling, I spent this week thinking more about how the ears will be incorporated into the body. The previous design had the ears wrapped around and hot glued into a BBQ skewer, which was placed in a hole drilled into a block of wood.

For the next version, I modified the skewer so that the ear attached to a flat area, helping to create a more natural ear shape when attached. The ears are now attached by a screw through the skewer, much sturdier than the hot glue. The bottom of the skewer is also attached to a screw. The plan is to design a body that has a series of channels that I can slide the screw and attached ear into. This would allow for easy switching between ear prototypes, and ideally even allow for adjustment of the angle the ears at which the ears are attached to the body.

After finishing with the next version of the ears, I crafted a model of the body I hope to make next week out of clay. This new body narrows at one end, maintaining the general shape of my original model which I hope will be able to model both a large animal’s head and a small animal’s body. For next week, I will likely start working in Solidworks to create a body that I can test the ear attachments to. After that, I will try to incorporate the servos into the design of the body, which should bring the prototype close to completion.

Building on the wood block model I created last week, I attached a series of Arduino controlled servos to the ears. Ear ear is has two attached servos: one controlling left/right rotation, and one controlling forward/backward motion. With this mechanism in place, I started to design a few simple behaviors to see how effectively my current system could communicate them.

I was fairly happy with the mechanism and the range of emotion it allowed me for designing behaviors. I wanted to spend more time working on behavior creation, but given that this was still a fairly low fidelity prototype, I decided to work on the actual body as a next stage.

This prototype body was created in Solidworks and 3D by my supervisor just to introduce me to 3D modelling. This body has no space for the inclusion of servos or ear attachment, but was really just a way for my supervisor to help introduce me to 3D modelling. Next week will most likely be spent in Solidworks, creating a better body.

After further experimenting with me previous model, I decided to abandon the springs in favor of more rigid attachment using barbecue skewers, since the spring allowed too much freedom of movement to consistently control the ear’s position. With some further trial and error around the shape and materials used to construct the ears,  I arrived at a system that allowed me to control rotation and forward-backward motion with three strings.

However, I the flexibility of the frame has made it difficult to consistently test the impact my changes would have on ear motion, as pulling on the strings moved the entire body as well as the ears. To solve this problem, I created a new model.

I used this block of wood to set the ears at a more natural angle (70°) and finalize my control system. However, controlling two ears (six strings total) with only two hands is difficult, meaning that the next step in this process will be some automation. I’m planning on attaching four servos, two for each ear, to this model to control the ears. This should let me make sure that this model is giving me the range of motion I will need to prototype behaviors later on.

For my first Cuddlebit prototype, I’ve decided to build a model that will allow me to experiment with ears, since they are a frequently used communication tool in mammal species, but not often considered in interactions with humans. I started by making a frame with a profile that I felt would be able to model both the entire body of a small animal (rabbit) and the head of a larger animal (dog) depending on where ears are attached to it. Right now I have rabbit ears that are attached to the frame by a spring, which allows for relatively free movement controlled by a string attached to the tip of the ear. Currently, the ears can be pulled in any direction, but lack rotational control, which will be the next thing I work on.

I’ve also started trying to create other types of ears, in particular a model similar to a German Shepard’s upright and slightly folded ear. So far, I’ve been unable to create a model that is able to fold when back in the same way as the dog’s ears. The folding motion of rabbit like ears is less mechanically complex than in a German Shepard’s ears, so I plan to move forward with the rabbit like ears for now. Ideally the final model will be capable of accommodating all sorts of ear shapes in the future, so I may have time in the future to come back to this.