control circuit of a humanoid robot (something like i-cub or Asimo)

[Ehsan Zakipour]

hello everybody
my friend and I are building the upper body of a humanoid robot. There are 24 dc motors in this robot the thing I want to know is what is the best way to command these motors simultaneously?


the design i had in mind is for each motor to have it's own micro for position and velocity control and then one master micro to command and control the slave micros. if this is the best way to go how does the master micro command slave ones simultaneously?

another question I have is what is the best micro for the robot to go with between arm and pic? i want the master micro to receive it's command from pc.
any help would be appreciated. thank you.

 

[arbj2]

some high speed communication should do the job.

1. RS485- simple to implement, but speed may be a issue, also full duplex communication is slightly complex.
2. CAN bus- Used in automobiles, may be best suited for motion control applications such as yours, has well developed library for this purpose.
3. Ethernet- Can achieve the very high speeds but extra interface circuit and connectors are required.
4. Wireless such as Miwi or zigbee- Can achieve high speeds, can also address multiple nodes simultaneously.

Your choice will depend on the kind of speed you need to achieve, also the cost.

My choices..

1.
I would prefer the wireless option (using the MRF24J40MA modules), the system is quite flexible and you can use the Miwi library or develop your own system. Also the nodes need only powered by 2 lines, this makes it very compact to use although I would prefer smaller size modules.

2. RS485


But its going to be a tricky job getting all those 24 DC motors to run in a coordinated manner, you probably have to design the master controller first, the individual nodes may also have to be semi-intelligent so they do not depend on the master controller for each and every action...just my thought

thanks
a

 

[Ehsan Zakipour]

thank you very much i'll check out the modules you mentioned.

- - - Updated - - -

again thank you for your reply but do you mean to use one module for each slave pic? it doesn't seem so cost effective right?
thank you.