hi guys,
i am making an autonomous robot that should stop at exact positions.....i hv avoided the problem of 90 degree turns by using four roller wheels in perpendicular directions(along the sides of the square robot)
nw my question is...
what's the best method for accurate breaking???
i hv noticed tht there are different types of roller or omni directional wheels...which one is better??(three rollers,four rollers...or more)

is it ok to use four different motors or is it better to use two motors with two shafts???

i need the motors to move in two opposite directions what is the best way to accomplish that???
is it better to use a DC motor or a stepper motor???
are there any other types of motors tht u recommend??
my personal idea at the moment is to use four DC motors and the three rollers omni-directional wheel....and alternating the direction through inverting the input to the motor......n still haven't figured out a way for one spot breaking

thanx krumlink for the fast response.....i appreciate ur recomendations

Originally Posted by Krumlink

Drive both sides of the H bridge Low OR high to stop it immedately.

DON'T DO THIS!!!! This will short out the power supply and blow out drive transistors! Turn on both the high side drivers or both the low side drivers to brake. Never, ever, turn on all four drivers of an H bridge at the same time.

dn't worry guys i got ur point however u wrote it..........thanx alot for ur replies.....i greatly appreciate them

I'm sorry, Krumlink, I thought you were suggesting turning on both sides at once.