1. A robot control system for controlling the location and position of an object to be controlled, which is fixed on a robot wrist, in accordance with data taught in advance, comprising: taught data memory means for storing the taught data; means for computing an error vector indicating an error in a wrist coordinate system corresponding to the positional error of said object with respect to said robot wrist; memory means for storing the computed error vector in said wrist coordinate system; command value computing means for computing a command value for a robot drive unit to correct said positional error concerning said object in accordance with the taught data of said taught data memory means and the error vector of said error vector memory means; and means for controlling said robot drive unit based on said command value.