I'm currently working on a walking biped, which will (in my most delirious dreams) be able to walk with a dynamic gait (ie no bent knees). See Dr. Guero robot on the web for what I mean.
All my robot main parts will be 3D printed, with the files being done in Tinkercad.
Since I'm on a budget, I'm using Dynamixel XL-320 smart servos, as they are the less expansive ones I could find. I will also be using a gyroscope/accelerometer.
I've already completed 1 of the legs, as a proof of concept and to validate that my 3D files were correct.
I've begun the long journey toward biped walking by having started the coding of the beast... I just hope that the OpenCM 9.04C controller I selected will have enough power (and RAM) to achieve my goal.
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/void-my-biped-robot
Fellow Humanoid Project
Hello, I just saw your post and thought I would introduce myself. I have a humanoid that I started building around November of 2016. I find myself sort of isolated in this pursuit as no one around me “gets it.” Anyway, I spend a lot more time than I would like confronting problems and would certainly like to have someone that does get it and whom I could bounce ideas off of and maybe share some of my successes with and also find out how they (you) resolved issues. Hope all goes well with your project.
Hello Badly-Bent,What size
Hello Badly-Bent,
What size is your robot? Do you intend it to be as small as mine or do you think big? 
Where are you in the building process?
What material are you using? So much questions… ;-) I will update this page soon to show up where in the process I am.
My Guy
Hello Kadersin, My guy (named Roman) is 17 inches high and uses sixteen RDS3115MG motors. I made a back plate out of Home Depot aluminum so didn’t have to drill any holes into the frame as it arrived, The back plate holds a raspberry pi 3 (because it has the wifi on board) an SSC 32-U controller, a TCA9548A i2c multiplexor that I finally got working. I then took the side rails off a mini breadboard to use as additional powerstrips, one 3.3 v and one 5 volt each is mounted vertically on the outer sides of the back plate. Needless to say, the back board is densly packed and I’m now thinking about a larger back plate?
My ping sensor seems to be on the fritz. So. Ping is currently disconnected from the TCA9548A mux but I have a BNO055 imu connected to the TCA9548A mux. I just this weekend (after about 3 weeks fighting i2c - not so much i2c but i2c mux issues) finally got results from the Adafruit BNO055 simpletest. Not sure yet how I’m going to implement accelerometer, gyroscope and magnatometer readings into the walking algorythm? Speaking of walking, it seems the RDS3115MG motors are notorious for being power hogs and out of 18 motors I ordered with my robot, 4 I thought were bad, Now I’m getting additional jitters and I’m not sure if its motors or something else in the electronics that putting noise on the SSC 32U busses? I just started my surfing for any posts about this problem.
I don’t know what your experience has been so far so, I’m hoping you fill me in. Let me know what you are dealing with and I’ll tell you what I did. Maybe it will help or maybe you’re more advanced than I am. Like I said I bought my bot in November and bought all the ancillary stuff as I realized I needed (or rather wanted) it. This does seem to be one of those money-pit hobbies. (Ace hardware knows my first name)
Anyway, I’m just glad to have someone I can talk to that understands the frustrations of this hobby. Thanks.
Badly-Bent “If the facts don’t fit the theory, change the facts.” ― Albert Einstein
Roman pictures
I forgot about my pictures because I keep all that on USB sticks. Anyway, one is a picture of the version1 gantry I made to hold the robot. Version 2 is still on the camera. It’s much bigger and has a steel rod with a drilled out slide so the bot can take a few steps. I’ll post those images later. The other image is the front view. Thabck view with the plates is on the camers will post later.
![|x]()
Enjoy?
Badly-Bent “If the facts don't fit the theory, change the facts.” ― Albert Einstein
Power & Stuff
Hello!
How do you power the Beast? Personnaly, I use a 7.4v LiPo battery. You have way more electronics than I do for mine. I’m currently using the Dynamixel OpenCM 9.04c to do the networking/controlling of the servos, so I do not have all the muxing you have for yours. Also, the servos you have look way more robusts than my puny XL-320…
Hey!I didn’t want to get
Hey!
I didn’t want to get into batteries early on in case I lose interest and batteries don’t do well when you put them away for a few months or years. So. I watched amazon for digital power supplies. One that I had watched for a few weeks finally was offered at a sale price about $59 - with prime, no shipping! Also, the digital meter gives me feedback about amp consumption so I see immediately when a motor is being overtaxed or those pesky electronic problems I mentioned earlier. This meter is dial-able up to 30 volts and up to 10 amps. My motors need 7.2 volts and idle about .5 amps. It goes up as motors are working to maybe 1.5 amps. Any more and it means something is not right. The RDS3115MG is quite powerful. Rated at 17.7 Kg of torque. But, I’m not convinced they are a quality product? Also, they use lots of power. I made a paper box that is the size of a 3 cell LiPo. Just to see how it will fit the frame and I can get two of those in the chest cavity (if needed - or wanted.)
I think Dyanmixels use a serial bus? So, I am wondering how the movements get coordinated? With SSC32U you send it a packet of motor id’s and positions and speeds and it receives the entire packet first and then fires off the pwm’s to only those motors in the packet at the exact same time then gives you feedback when the operations have all completed.
More later tonight, I’m at work right now.
Badly-Bent “If the facts don’t fit the theory, change the facts.” ― Albert Einstein
Where are you in the building process?