FRICTION CONTROL,dead zone control

I am doing a position control of the motor. The motor response has the deadzone its respose to the control voltage. I found it very difficult to eliminate the deadzone due to the friction at near zero velocity region. On of the method that most of the people suggested is to add a high frequency diether signal to the control voltage. But how do actually this signal added to your system. How to determine the magnitude and the frequency of the diether signal used. Any other method to avoid the dead zone.Suggestion,comments and any sort of help is mostly welcomed. thanking you kristo