Fast sensor corrections of robot motion paths processed in real-time by control algorithms running in parallel

Abstract

Robot motion controls (especially for non-Cartesian kinematics of the robot) are realized with strong real-time demands. In industrial use they are primarily designed to work without sensor feedback. Within the control different levels of coordinates are necessary that rank from the Cartesian world to the realization of motions by the joints. A connection of the sensor to the Cartesian level results in a long reaction-time which often is insufficient either for the data rate of the sensor data or for the demands of the application. This paper describes a method which offers advantages because of parallel integration of the sensor in the robot motion control. These advantages are: great modularity by decentralization, fast reactions in real-time by parallel computing of the sensor data, implementability of various, application-specific control algorithms for sensor data, a relatively slow communication with the robot motion control on the Cartesian level and fast, immediate sensor influence on the robot joints. Since sensor corrections are performed by the use of a differential method (inverse Jacobian matrix) fast corrections have to be limited to certain amounts. Nevertheless corrections of robot motion paths can extend to any value by overlaying the fast corrections by additive slow correction values.