Can u help me?

I would like to get help on a situation of mine.
I want to design a circuit to measure the speed in rpm of a shaft and then in accordance to the measured value of the speed I would have to operate 3 motors.There is one more constrain to this,the 3 motors will have to be operated in the both directions(forward and backward) in accordance to the speed detected.
Please help me.

You need to be much more specific. What kind of speed range have you in mind? What kind of motors do you intend to use? power rating , AC or DC , brush, brushless, induction ,stepper etc.
How do you envisage the three motors interacting with the shaft speed?
If you could provide us with a layout drawing of what you want someone may be able to help.