OldBotBuilder
Resolved by Jeremie!
I decided to drive my Robotis Bioloid Robot with an EZ-B4. I removed the Robotis CM350 and replaced it with the EZ-B4. Wiring was no problem. The AX-12s are connected to a 12V supply, the EZ-B4 is powered by a DC converter set to 7.4V. A 6 port expansion hub connected the EZ-B4 Uart (D5) to the signal chain of the 18 servos. My scripts are in: AX-12Test2.EZB The Dynamixel plugin is included. The Initialize Lester script initializes UART 1 to 1000000bd, sets up the EZ-B head and hands servos (not connected), clears all the AX-12 servo speeds (V1 - V18) positions the servos to put Lester in the sit position with arms down, then sets all servos to $speed (set @ 5).
The Auto Position Action 'Arm Swing' is set to repeat. Frame arm 0 has the arms down, frame arm 1 has the arms out, and frame arm2 has the arms up. I have a serious timing problem. When I Execute Arm Swing, the arm up/down motion is very erratic. Here is a video: Arm Swing The scope traces show the EZ-B commands at 3.5V peak and the AX-12 responses at 5V peak.
BTW - Reference my thread: Interface Ez-b To A Trossen Robotics Hr-os1 Biped Robot
DJ,
The new plugin lets me change the transmission baud rate but does not change the baud rate the servo expects.
I am testing with 2 new AX-12s - V1 and V2. They both work at 1000000bd but not at any other bd rate.
Is there a way to change the servo's baud rate?
Thanks for your efforts. I think an EZ-B only controlling the AX-12s in my robot can be made to work very well.
Here are the AX-12 Test scripts: AX-12Test.EZB
According to someone in the Trossen forum it seems that you can change the AX-12 baud rate with a USB2Dynamixel.
That is correct. The baud rate option changes the baud rate from the ezb. It does not change the baud rate of the servo. As previously mentioned, the baud rate of the servo must be changed ahead of time.
I am certain robotis has a tool for changing settings? They must have some sort of utility for configuring their servos? I have no idea what robotis makes their products so difficult to use...
DJ,
Yes, Robotis has a tool for inspecting and changing all the registers of the AX-12s. I have all the necessary hardware and software, unfortunately, Robotis messed up the FTDI/USB driver so an older version must be used. My computer updates any driver it sees and an "old" one. I must get rid of the application that is doing that.
As soon as I get the old driver re installed, I will try setting the AX-12 bd rate.
Thanks again.
I have used the USB2Dynamixel and the Robotis Dynamical Wizard software to change all my servos bd rates. Register 4 from 1 to 16. 16 switches the servo bd rate to 117647.1 bd. That is close enough to 115200 bd to work.
After the change, I tested the 'bot with the new Dynamixel plugin and it works. I have some mechanical issues to fix but I'll have more results soon.
It's looking good!
@OldBotBuilder Wow.... you stuck with it, so awesome... I have yet to mess with dynamixels.... Maybe one day... It's threads like these that will make using dynamixels that much easier...
Thanks
Great to hear - i also think ez-robot will need to make a dynamixel config tool in the plugin since robotis can't make one that non-programmers understand.
DJ,
I hope you do add more dynamixel plugins. The AX-12s are very good servos if you don't mistreat them. The gears are plastic and they will strip if stressed. You can get gear sets at:
Trossen.
Is it possible to change the Configure - servo Fine Tune Profile so that values other than 90 can be entered as the 'trim from' value? For my 'bot Lester, I would like to trim from: V1 = 40 V2 = 140
V7 = 60 V8 = 120
All the rest 90.