[R.C.]

Create a step function. Also, create a wide base of 127. You could either do this

if (drive_left >127 || drive_left<150)
drive left = 127;

or

create a funtion in which it takes the pwm value, splits it into 14 or 17 sections. Then it will return a number and that number could stand for a wide base of numbers:

ex: (pwm01/17) = 14. 14 would stand for the value 236. If the answer came out to be 14.2, C and C++ cuts numbers so that equals 14. This is pretty much a step function used in math.