RoboSavvy Forum

AX-12 control with PIC32

2011-06-15T14:39:21+01:00

I think the problem is with power supply.
my adaptor can supply max 500mA

Statistics: Posted by def — Wed Jun 15, 2011 2:39 pm

AX-12 control with PIC32

2011-06-15T13:22:58+01:00

Is there an load on the servo ?

What is the MAX TORQUE and TORQUE LIMIT set to ?

Is your power supply OK ?

Statistics: Posted by i-Bot — Wed Jun 15, 2011 1:22 pm

AX-12 control with PIC32

2011-06-15T12:55:36+01:00

I'm using dynamixel wizard
whenvery i write a new position, torque enable turns to off, speed becomes zero and it doesnot go to desired position

Statistics: Posted by def — Wed Jun 15, 2011 12:55 pm

AX-12 control with PIC32

2011-06-15T10:57:27+01:00

Does the AX12 move OK with the Robotis utilities ?

Do you write the (H) and (L) position bytes in the same instruction packet ?

Statistics: Posted by i-Bot — Wed Jun 15, 2011 10:57 am

AX-12 control with PIC32

2011-06-15T09:03:11+01:00

Hello everyone
today i printed my circuit and everything is working fine.
I'm able to detect the dynamixel.
but now i have a different issue.
when i give a goal position to my ax-12; it doesnot moves; or moves randomly and doesnt reach the desired position.
I dont understand what can be the problem

Statistics: Posted by def — Wed Jun 15, 2011 9:03 am

AX-12 control with PIC32

2011-06-07T07:50:04+01:00

I just have the chip; board i'll print myself

Statistics: Posted by def — Tue Jun 07, 2011 7:50 am

AX-12 control with PIC32

2011-06-06T23:06:48+01:00

Is it a chip or a board you have ?

The direction control is driven by the TXDEN output which is mapped by default to the CBUS 2 I/O. You should not need RTS and CTS.

Statistics: Posted by i-Bot — Mon Jun 06, 2011 11:06 pm

AX-12 control with PIC32

2011-06-06T18:28:56+01:00

Hello I-bot;
i got a FTDI ft232 shipped to me today.
now I have one doubt, which pin should I use as Direction control?
is it that I should short RTS and CTS and use them as direction control?

Statistics: Posted by def — Mon Jun 06, 2011 6:28 pm

AX-12 control with PIC32

2011-05-31T11:26:11+01:00

There is an FTDI clone for PIC here:
http://www.microchip.com/forums/tm.aspx?m=261649

I didn't try it, but have done similar on other USB processors. Please be aware that using a non FTDI device violates the FTDI driver license conditions on the PC.

Statistics: Posted by i-Bot — Tue May 31, 2011 11:26 am

AX-12 control with PIC32

2011-05-31T11:25:05+01:00

basically what a dynamixel manager does is it checks for all the possible baud rates possible for a dynamixel, it works with FTDI as after searching at one baud rate, it sends usb setup packets for configuring the FTDI for next baud rate, and then it agains checks for all the IDs at that baud rate, I think it is possible to get my pic18f4550 to work exactly as FTDI, i'll configure it to use those setup packets for changing its own baud rate.
But as of now as you said, the problem might be with baud rate and ID.
what I can try is program my 18f4550 for one baud rate, broadcast some action, then one next baud rate, atleast that will give an idea if my logic is working or not.
I think it'll be ok, just to connect tx pin to data pin of ax-12 and broadcast instruction for glowing led or rotating to some angle.

Statistics: Posted by def — Tue May 31, 2011 11:25 am

AX-12 control with PIC32

2011-05-31T11:09:07+01:00

I have had AX12 arrive in different states of configuration (baud, ID). I just think it is good idea to check with an FTDI/USB2Dynamixel and Dynamixel Manager.

Statistics: Posted by i-Bot — Tue May 31, 2011 11:09 am

AX-12 control with PIC32

2011-05-31T10:40:26+01:00

does that mean my problem stays solved if i use FTDI?

but i've tried manually sending the ping with a push button programmed to send the command, still i do not get any reply from ax-12
what might be the problem?

i'll give it a try with ftdi also

Statistics: Posted by def — Tue May 31, 2011 10:40 am

AX-12 control with PIC32

2011-05-31T10:42:37+01:00

Robotis programs which talk to the CM5/CM510 can use almost any different USB serial converters. Robotis programs which talk direct to servos require an FTDI converter and use FTDI drivers to set the speed etc.

Statistics: Posted by i-Bot — Tue May 31, 2011 10:33 am

AX-12 control with PIC32

2011-05-31T04:57:43+01:00

yes my led flashes when i power up.

robotis says default ID of servo is 1, so i am using that

for usb to serial convertor, i'm not using FTDI, rather i've programmed my pic18f4550 as usb to serial convertor.

the major problem is i've lost my logic analyser, otherwise all the scenario would have been more clear.

the adaptor i'm using is a variable adaptor with vout 1.5 to 12v adjustable and 500ma rated current; will this current be a problem? as ax-12 are rated 800ma.

Statistics: Posted by def — Tue May 31, 2011 4:57 am

AX-12 control with PIC32

2011-05-30T22:23:41+01:00

Does the led flash when you power up the AX12 ?

How did you check the ID of the servo ?

so any usb to serial convertor with 1Mbps baud should work fine with a little bit of tuning.

Can you expand on what you tried ? I have never had a problem using any FTDI based usb to serial with the buffer tristate enables linked to TXDEN.

Statistics: Posted by i-Bot — Mon May 30, 2011 10:23 pm