(...) I assume that was me; I posted a message with a link to an LDraw file of a robot I came up with that uses that design. I can't take all the credit for it, however: I was inspired by Simen Svale Skogsrud's web page on his Vector Rover using (...) (25 years ago, 21-Sep-99, to lugnet.robotics)
(...) You can achieve all 5 of these criteria with the standard differtrans, if you put a rotation sensor directly on each motor shaft... [ I've build such a 'bot, and it appears to work pretty well (ie it measures distance accurately, and drives in (...) (25 years ago, 21-Sep-99, to lugnet.robotics)