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Topic: Humanoid Bipedal Walking Robot - Needing Guidance  (Read 4388 times) previous topic - next topic

Eggy

I have just started studying engineering and am very eager to start a project around a bipedal walking robot.

I currently have no programming skills or knowledge in this field but I will teach myself everything and learn everything I have to to complete this.

THE PROJECT:

I want to build and program a bipedal robot.
  • Basic Walking to start with
  • Eventually Wireless Control (maybe from a PS2 controller or Android Phone?)


Should I start with something that only consists of legs?
http://www.robotshop.com/en/lynxmotion-biped-robot-scout-bps-ns-servos.html



Or just buy this humanoid one or similiar.
http://www.ebay.com.au/itm/17DOF-Biped-Robotic-Educational-Robot-Kit-with-MG996R-Servos-32CH-Controller/171813905444?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3D14911896f1664aacad434068c129d9bf%26pid%3D100033%26rk%3D2%26rkt%3D4%26sd%3D221254696247


Also, what Arduino board will I be needing?
It will need:
   
  • Wireless ability
  • Battery Pack Operated
  • Control up to 20 servos



SIDE NOTE:

Please any guidance would be a great help, if none of the above examples are decent I'm happy to be pointed in the right direction, cheers.

CrossRoads

20 servos, need a Mega I believe to have enough timers.
https://www.arduino.cc/en/Reference/Servo
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

zoomkat

Quote
Please any guidance would be a great help, if none of the above examples are decent I'm happy to be pointed in the right direction, cheers.
You might look on youtube and see if you can see any of these bots in action. They may not be as exciting as they might look. Bots with a lot of servos often use separate servo controllers, like the bigger bot you linked to.
Google forum search: Use Google Search box in upper right side of this page.
Why I like my 2005 Rio Yellow Honda S2000  https://www.youtube.com/watch?v=pWjMvrkUqX0

Eggy

20 servos, need a Mega I believe to have enough timers.
https://www.arduino.cc/en/Reference/Servo

Awesome thanks, do you know if it has wireless option built in? Or will that require a mod?

You might look on youtube and see if you can see any of these bots in action. They may not be as exciting as they might look. Bots with a lot of servos often use separate servo controllers, like the bigger bot you linked to.
YouTube videos of both robots are exactly what I want, they seem to be the cheapest option for how advanced they are.
What do you mean by separate servo controllers? A separate arduinonpard for every servo?

zoomkat

Quote
What do you mean by separate servo controllers? A separate arduinonpard for every servo?
Your homework assignment.
Google forum search: Use Google Search box in upper right side of this page.
Why I like my 2005 Rio Yellow Honda S2000  https://www.youtube.com/watch?v=pWjMvrkUqX0

keeper63

Also note that for many of the main joints, like the hips, ankles, and shoulders (and ideally all joints) you are going to want to use metal gear, dual ball-bearing servos, because of the amount of stress at those points. This translates into a lot of money - just for the servos.

Also note that such servos have no position feedback - if you want or need that, you'll want to get some so-called "smart" servos (even more $$$).

You'll need at minimum an IMU to keep your balance (even then, there are no guarantees).

I dare say that you are jumping into the deep end of the pool without even understanding what water is, if you get that analogy. This is very ill advised. You would be much better off to first study the Arduino and microcontrollers separate from the rest of the hardware, then learn how to control something simpler (a two-wheel differential drive desk-rover platform would be ideal), then move up to a very simple bipedal robot (like the Parallax Toddler robot), then gradually up to the full biped (and/or maybe hexapods). Each level is going to be a very large challenge - trust me on this. Just getting a simple desktop rover to autonomously navigate from point A to point B on the floor, avoiding obstacles, is a great challenge all on its own.
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

CrossRoads

Wireless - there are some Mega derivatives with wireless.
Just as simple to use a 433 MHz Tx/Rx pair tho for 1-way comms, with VirtualWire/RadioHead for data transfer.

If you want, there are plenty of 2.4GHz options also, nrf24L01+ modules.
http://yourduino.com/sunshop2/index.php?l=product_list&c=12
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Eggy

One of these robot's are around $300 and the servo's that they come with seem to work perfectly fine on the youtube video's.

I can invest in lesser robots and build up my knowledge that way but I don't have funds to burn.

My thoughts are to buy this bigger one, start tinkering with just a simple build. One servo, then slowly build limbs and as I get better start building the entire robot and programming it. That way I'm not throwing old parts out and wasting as much.

---> If this is definitely not the way to go about it and I'll be wasting my time please let me know.

I know I'm jumping into something I have no idea about but that's exactly why I've made this post, as I said I'm willing to learn everything I need to.

I will definitely study up on Arduino before making a purchase, and perhaps a single board and a few bits of hardware to start off with.

Thank's for all the feedback and help.

keeper63

One of these robot's are around $300 and the servo's that they come with seem to work perfectly fine on the youtube video's.
My advice then would be for you to make sure you carefully research the servos they use; standard low-cost servos typically use plastic bushings and gearing - which will stand up ok for a short amount of time (enough for a youtube video) - but in short order become worn down quite quickly. If you purchase this chassis and use the servos it comes with, expect and budget for their replacement in the near future (depending on how much you use them, you may get a week - or you may get a few months). Those servos which have to move the most mass (as I noted earlier) will wear out much quicker than the other joint servos.

I can invest in lesser robots and build up my knowledge that way but I don't have funds to burn.
Quite understandable - but realize that robotics is not a cheap hobby in the long term.

My thoughts are to buy this bigger one, start tinkering with just a simple build. One servo, then slowly build limbs and as I get better start building the entire robot and programming it. That way I'm not throwing old parts out and wasting as much.
If you insist on going with such a chassis - the number and type of brackets should allow you to create a simpler "toddler" robot with fewer servos which would be a better learning opportunity as a stage in developing your skills to build and maintain control over the larger machine.

---> If this is definitely not the way to go about it and I'll be wasting my time please let me know.
My earlier thoughts still stand. The problem you might run into is being discouraged by failure; you are jumping into an engineering and software challenge that is anything but small, with little to no knowledge of the subject matter (as expressed here on this forum, at least). That isn't a recipe for success.

I know I'm jumping into something I have no idea about but that's exactly why I've made this post, as I said I'm willing to learn everything I need to.
There's a ton of research out there on bipedal robotics - so I would suggest looking into those papers and research as you construct and develop your "toddler" version of the robot. When you get that working well, rotate the servos out for building the larger 2-legged lower half of the full robot - put those servos in the lower mass areas, and rotate in new servos for the other higher wear joints (that will maximise your servo usage time). Read and try to understand every tutorial, blog post, forum, research paper, etc that you can find before and as you build your robot. Doing so may help to answer questions, while also providing inspiration. Above all, approach this in a slow and steady modular approach to help avoid any burn out on the project.

I will definitely study up on Arduino before making a purchase, and perhaps a single board and a few bits of hardware to start off with.
That's a good thing to do first - learn how to control a servo, then multiple servos - then apply that to building your toddler robot from the chassis parts. Then learn how to control the toddler - to make it walk, to keep it upright without falling, etc.

Also - study up on forward kinematics (FK) and reverse/inverse kinematics (RK/IK) - this knowledge will be needed to help prepare and implement a proper bipedal robot.
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

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