Real-time Positional Error Compensation for Industrial Robots.

Various sources of error (e.g. manufacturing tolerances, arm deflections, gearing-backlash etc.) influence heavily the positioning quality of the industrial robot. Even very small error components can drive the robot endeffector far of its expected position. Robot manufactures typically neglects such effects in the kinematic modeling of the arm by applying nominal (idealized) kinematic parameters; one standard kinematic model is created for all robots in the same series. Thus, in application areas which require high positional accuracy the industrial robot shows less of a capability. This paper addresses the kinematic modeling of industrial robots, including error effects. A methodology for improving robot accuracy through identification and real-time compensation of errors is presented.