Selecting an optimal bus to connect the motors and sensors:

To limit the amount of wiring, the Humanoid Platform will only contain one power bus and one data bus. This simplifies the amount of wire that will need to snake around the various moving joints.  The power bus will be constructed of 10 AWG flex cable. This leaves the data bus.  I was considering CAN-BUS but now think a daisy chain Ethernet might be a better option. Ethernet is inexpensive and ubiquitous. Most existing industrial bus frameworks can run over Ethernet and Ethernet enables the use of a vast number of existing open source frameworks or I can create my own.  I was concerned about latency but a couple of papers suggest multiple network hops (daisy chain) will run in about 200us.  The ARM processor I am planning on using for the motor controllers comes with Ethernet; some even come with a two port Ethernet switch. If I use one without the switch I could add a simple IC two port Ethernet switch each of the motor controller boards.