MD-Hund

     For a long time I wanted to build a quadruped robot. And... you guys may have seen in some of my videos that I have many dogs at my home (precisely five). What better inspiration I would have to build a robot dog?

     Below you see my little buddy Sebastian, which accompanying me in the long nights in the lab.

 

 

 

     Mechanics

     The design process of the parts begins with a brainstorming, then I adjust the drawings to get something satisfactory.

     Specifically for this project was also required a study on canine anatomy. Actually a very superficial study, just to maintain a similar morphology to a real dog.

 

     All the brackets and mechanical parts are homemade with polystyrene sheets and a bit of PVC pipes (except for the chest, made out of aluminum).

 

     Here (Plastic handling to make DIY robotic parts) is a complete walk through of the Humerus part of this project.

 

     What's new in my process of making parts is that I used a 2 mm thick aluminum sheet for the main part of the body. But the technique was the same: metal ruler and sharp blade (and pliers to help break off the unwanted parts).

     To give it a good finish, I have sanded it and end rubbed with steel wool. I used mask and gloves because the aluminum powder is irritating.

 

 

     More pictures of mechanical parts:


      The linkages are made with paper clips. The Lego shock absorbers are just for aesthetics.


      Here is MD-Hund taking his first steps (in the air :D).

 

 

 

     Electronics

     The brain is an Arduino Mega 2560, with a sensor shield to facilitate the connections.



 

     The power is provided by ten Ni-MH 2500mAh AA batteries. They are arranged in two packs of five batteries, and the packs are connected in parallel, which provides a total of 5000mAh @ 6V. To take some weight off of the body, some batteries were in the legs (two on each leg). Two batteries are inside of the chest.

 

 

 

 

     Programming

     I intend to make him walk autonomously and probably remotely controlled. For the autonomous walking gait I'll be using a HC-SR04 ultrasonic sensor, just for a simple obstacle avoidance.

     The code for walking is just beginning (I have to learn a bit about Inverse Kinematics).

 

 

 

     Additional info

     Updates:

     @ October 19, 2014: added new pictures and info. Added new video that shows the head/neck mechanisms, and the tail which reacts if something is detected in a range of less than 30cm.

 

 

     References:

     http://www.hpirobot.jp/g-dog/en/top/ - [TOP] G-Dog -G-ROBOTS- - The page of G-Dog (from HPI). Certainly influenced me a lot. For example the head of MD-Hund is nearly a copy of G-Dog's head.

     https://www.youtube.com/watch?v=1E3v4xHEVSc - Robotics - How to Engineer a Dog - YouTube - A great inspiration for me to start my project.


This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/md-hund

Das ist ja geil!

this is awesome! can’t wait to see it walking on it’s own.

Well, dog #6 in Dickel’s

Well, dog #6 in Dickel’s home.

I am always thrilled when i see your projects. A quadruped is indeed a challenge but I am sure you will master it. The option to put the batteries on the legs is brilliant, not only taking away some weight from the body but also lowering the center of mass.

This is great work!

Nice to see.

Amazing AND INSPIRING as

Amazing AND INSPIRING as always Dickel. Very cool of you to take on a new design as most quadrupeds on LMR have “insect” and “spider” like structures. So excited to see more of the robot-dog!

Beautiful

+1 with Enigmerald.

I’m always impressed by the quality and finish of each part in your work.

Even if i’m not posting each time I’m following your work. thank you for posting.

 

Do you plan to make be able to turn ? by a special gait ?

It looks very nice! I’m

It looks very nice! I’m surprised you got it to work with NiMH batteries, though. I tried to power Katka (which is much smaller and uses much smaller, 9g servos) with 4 NiMH batteries, but it could barely bear its own weight with them. Switching to a LiPo fixed it instantly, even using a huge 3S 1C 2.2Ah lipo pack for the radios (as heavy as the nimhs). I suppose they just don’t give enough current…

i tried too but 10NiMh should be enough

i use 8NiMh for my robot and are enough to move 2kg of payload.
Putting some of the batteries on the legs it’s a nice idea!

hmm, maybe I need more

hmm, maybe I need more batteries in parallel instead of in series

Your work is very inspiring

Your work is very inspiring and amazing…Can’t wait to see the MD-Hund in action…Kind of like BigDog from Boston Dynamics! :slight_smile:

Big Dog is kinda lame

Big Dog is kinda lame compared to this one, as it has the legs backwards. This one looks more like a real dog.

At the first glance i

At the first glance i thought it has something to do with Boston Dynamics. Fantastic and NEAT work. I wish I could make bots pretty like yours. Truly inspired. 

+1 to Deshipu , Boston Dynamics bots dont look like real ones,they have backward legs,while this one looks much more cool !

Amazing build, Dickel. Your

Amazing build, Dickel. Your handiwork in general and your craft with polystyrene in particular is nothing less than awe-inspiring. Hope this beauty will receive the programming attention it deserves :slight_smile:

I’m curious though… How many DOFs are there per leg? And in general how many servos did you use and where? I can only see two servos per leg, but it kinda looks like there is one near the foot as well?

And BTW inverse kinematics isn’t actually that complicated after all when we’re talking a few DOFs per leg. But once you have more than 2 servos rotating in the same plane it’s quite another story I believe :wink:

EDIT: After a second look it DOESN’T look like there is a servo near the foot…

"Big Dog is kinda

"Big Dog is kinda lame"

Hmmm… have you seen the thing walk? It’s one of the most amazing quadruped robots I’ve ever seen :stuck_out_tongue:

Dankeschön!

Dankeschön!

Yep, it’s a big

Yep, it’s a big challenge. I would like the placement of the batteries in the legs was enough to make this robot walk, but I’ll have to change the servo motors. Ok, let’s go ahead!

Thank you very much!

Thank you very much!

Thank you very much.As I

Thank you very much.

As I have already mentioned on the post, for a long time wanted to build a quadruped, I just did not know it would be a dog. But recently it came clear to my mind that this project should be a tribute to my little buddies.

Re:

@jnx, robodude95 and Dipanjan: My project being compared with Boston Dynamics… I’ll take that as a compliment. :slight_smile:     Thank you very much guys!

Thank you very

Thank you very much!

Certainly! I guess the ability to do turnings must be an inherent task of this project. Many features of my design were inspired by HPI G-Dog (https://www.youtube.com/watch?v=5uZ-JcBAcwk) and certainly I’ll be studying his ability to make turnings.