Bajdupod 996R: first steps from Bajdi on Vimeo.
After blowing up a couple of expensive 8A UBECs I think I have found a solution to powering the 18 servos. I am now using 3 8A UBECs, each UBEC powers 2 legs / 6 servos. I have written a basic walking gait to move the hexapod forward, backward, left and right. I’m using inverse kinematics to calculate the servo angles. The code still needs a lot of improvement, I want it to move a lot smoother. For this I’ll need to move the servos in little steps. Writing that code for 18 servos is not so easy, certainly as I refuse to use the delay function. That’s to easy 🙂
I had a bit of trouble finding out how much I could move the legs and keep the hexapod stable. In the beginning I was moving the legs to far for/backward and that caused the hexapod to fall on it’s ass :p Takes quite a bit of time figuring everything out…
- Replace all the servo horns with metal horns (are on the way from China)
- Replace the original base plates with self designed laser cut acryl plates, the chassis I use now is to small, I’ll make it a little bigger so I can fit my Lipo and UBECs inside the chassis
- Replace current servo PCB with new version (is on the way from China)
- Replace Arduino Mega2560 with a Seeeduino Mega2560 (Seeeduino version is smaller)
- Write some fancier code so the hexapod moves a lot smoother and I can control the speed of the servos (this will be very hard)
- Fit a second micro controller with a nRF24L01 module so I can remote control it.
- Add a shit load of LEDs and let it dance, Gangnam style 😀
4 responses to “Bajdupod 996R: first steps”
I thought about the BEC method of voltage control also, but ended up powering mine off of a buss that has a LM2596 Buck Converter powering it from 7.4V Li-Po’s. I went with the 7.4’s because of the thin profile that you can get them in. That has worked for me so far. Like you, I’m working on smoothing the gate and have been looking at the VarSpeedServo library. There is so much I want to do with the hexapod but first I want to get it walking with a smooth and precise gate. Good luck with yours.
The LM2596 is a 3A regulator. I know it very well as I use it on my Bajduino Mega 3A -> http://www.bajdi.com/something-different-a-crash-robot/bajduino-mega-3a-2/
My hexapod draws somewhere between 15 and 20A when walking so it’s not an option.
I’m from Brazil and i’m making a hexapod like you. ^^
Now i’m writing the code, but i would like to know how you learn about IK, if you are using a software to help or something like that, i’m having many troubles with the IK :/
Thanks, i’ll wait for your answer.
I used this guide to learn about inverse kinematics: http://www.engineer-this.com/IK.shtml