TAMI Part 1: Preface, 3D printing and soft robotics

I’ve been very quiet on the writing front. It seems a full time job and life to live doesn’t leave much free time for writing – at least for me.

This is a project that’s actually been in the pipeline for years. It originated with myself and a friend perusing the idea of robotic human enhancement with the idea being an additional set of robotic arms that could be hip mounted to do additional tasks while the user arms were occupied. MIT have already done this kind of thing so this would really be designing this kind of robot. This was first thought up by myself and my friend in around 2015 whilst in university. I bought a bit of Aluminium and a few servos but never actually got round to doing the project.

Enter TAMI V2 (it won’t be known as V2 from now on as the first was never actually made). I’ve been wanting to make human augmented objects for ages, I’ve done a smart watch, smart glasses and part of a smart ring so far but these are pretty standard things to make – hip/shoulder mounted smart arms however are something else. The original TAMI design was solely a 2DOF articulated arm that could move in an arc left to right (from the users perspective) and the end effector could move in an arc perpendicular to the first segment movement i.e. up and down. This kind of arm doesn’t have a particularly useful operating envelope and can’t do that much outside of the given range – the operating envelope for this style of arm being the surface of a sphere.

I’ve since had a fair bit more experience with robotics since then and have been very interested as of late in soft robotics and continuum/tentacle/snake/trunk style robots. Continuum robots are the kind you find in films to emulate tentacles or in a few research applications to date. I haven’t really seen many or any in production as of yet.

Example of a tentacle style robot

Most of these robots are based around the same style of operation, tendons creating tension of segments of an arm causing the compliant segments to move. The segments are generally connected by springs or other spring like structures.

The one difference however is that all that I have seen have been based on solid structures. I haven’t as of yet seen a (near) fully 3d printed version without the additional need for springs or spring like structures.

I’ve gone through a fair few design iterations to get to this point but I decided to try and make a fully 3d printable version or at least fully 3d printable segments with minimal additional assembly requirements. My final 3d printed version is flexirigid and capable of bending without breakages.

The main aim I have of these segments however is to incorporate bend feedback into their design. To allow for this, I have incorporated a channel through the middle of the “bone” (I’ve decided to call segments bones and points where two bones join, joints – similar to standard human biology) where I can essentially generate an optical flex sensor.


First generation of bone design

As can be seen above, the bone has a thinner segment designed to bend along with holes along the base where tension can be applied. I originally got this part 3d printed externally but it turned out to be really stiff. This was the point at which I decided to finally buy my own 3d printer and some TPU filament – something I’ve been meaning to do for a while!

The final aims of TAMI was for eye in hand cameras with control from a PI along with integrated image/object detection and smart tracking.

This project will be split into multiple posts so stay tuned for more updates!

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