My 3D printed omni-directional mechanum wheels for Ghost the inMoov

I've made 4 of these, from ABS, with the Flashforge 3D printer and hope to make them work on my inmoov, 'Ghost'.  

Perhaps I might have to reinforce the centres with metal washers or similar to prevent them being damaged.  I think I will have to add weight to the inMoov base to prevent tipping as the completed inmoov is quite heavy. This will no doubt add further stress to the wheels.  There are 8 bearings around the outside of each wheel to enable the conical sections to turn. It remains to be seen if the wheels will be strong enough but I feel that they will be okay on smooth surfaces.  

And here's a pic of what Ghost looks like now, with his Adafruit Trinket-controlled neo-pixel ring, finger-tip sensors and his new shoulder and upper chest covers. 


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juerg's picture

Hi Humanoid Your bot looks

Hi Humanoid

Your bot looks great! Did you recreate the head parts yourself? Did that once too to get rid of all the screws. Have you added rubber rings to the fingers?

Not sure about your wheels. Mine have a 15 cm diameter and 14 rolls per wheel. I have 1 12 Volt and 1 6V battery in the bottom of my cart and the base is 36*40cm (middle of the wheels) and its built with aluminum profiles. The wheels are mounted on the motor axis and the motors attached to the alu-frame. Total weight  of cart and bot might be close to 50 kg, so about 13 kg per wheel. Not sure whether your ABS wheels will  provide enough friction to do all the movements. To use it on carpet the motors will need to be very strong as the rolls sink into the material. I would select faster motors on second thought but it will need software control for smooth acceleration, course changes and breaking.

And I run into problems using the motor driver shields and the pins as some of them get used/blocked by the shields. You can see the list of HW I used in my YouTube video comments.

Keep it going!

Juerg

Humanoid's picture

Ghost bot bits

Hi Juerg, 

The finger-tips have sensors in them. The black in the finger-tips is the conductive foam which compresses against the little copper triangles when the tips move. Marten and Gael's design, I believe. They were very fiddly to do. I am waiting for a SIP resistor to arrive from Germany to get them working. I'm planning different sensors for the left hand, using other conductive materials.  

My new head has a lot less parts. I found the 1-part face without holes on Thingiverse. The skull is in 3 parts (I hate skull gaps) with only 6 screws altogether.  That way I get quick access to the whole inside skull without dramas and without removing the lower back skull which holds the ear surrounds in place permanently. I joined the parts with acetone and filled the screw holes and disguised the joins with fine white gap filler which dries invisibly and sanded it with fine sand paper.  The face is connected to the skull with magnets in four places so I can remove it in seconds for access to the front of the inside head. That way I don't need screws.

My mechanum wheels are similar to Markus' but much smaller.  They cost only a few dollars and were fun to make and if they are not strong enough I'll use them for another wheely-bot.  They seem stronger than I thought they'd be though your super bought ones are much better.  There's no way mine would run on carpet without toppling over.  

Your elevator system is amazing. I don't think I'll be doing anything that high-tech.  I can see how the extra weight requires stronger motors and wheels.  I like the servos on the front.  I assume you are using ultra-sonic sensors on there to stop him banging into things.  It's a cool set-up.  I have that set-up on a wheely-bot and was considering doing that but I thought I might try with the PIR sensor first.  I low-height sensor is a good idea to avoid Ghost falling flat on his face! 

I'd really like to use Gael's leg stls and figure out something temporary with those - like roller skates!!  (I'm only half-joking there).  I wish he'd post them 'cause they look awesome. 

I thought I'd just use an L298N motor driver at first. It was about 3 bucks on ebay. I might even throw a spare Raspberry Pi in the base. 

It's all trial and error here but it's all good fun. 

Cheers,

-Annie (Humanoid) 

juerg's picture

I have a mega in the base and

I have a mega in the base and I use the adafruit 4 motor shield for the motors. With the servos and the sensors I used up all the analog pins.

A raspi might be a bit bored with only the base to control

I currently control the cart with a joystick which is rather easy to implement.

I will need to make ImMoov be able to send commands to the base on its own over a serial line. In Markus's software he already has added interpretation of commands over the serial port.

juerg's picture

you are from Melbourne,

you are from Melbourne, right? It looks like some others from there are building InMoovs (from the map of builders). Ever met one of them?

 

Humanoid's picture

No, I'm from here.

Juerg,

No, I'm from here. The triffids were invading that night, though.

I don't know any other inMoovers in Australia. There probably aren't too many of us.

juerg's picture

if you scroll down on the

if you scroll down on the main page of inmoov.fr you see a map. It's a bit outdated as currently no new entries can be made. but you should at least have one close by.

Looks like a fun night.

Spent once (about 15 years ago) a month in Terrigal right on the beach.

GroG's picture

WOW !

Great Build Humanoid .. very impressive !
Nice color combo .. really excellent quality ...  Kudos !

and even your nails match with InMoov too ;)

 

wkinne's picture

looks sweet

are you sharing the stl files?

 

thanks