Method and system for robot end effector path correction using 3-D ultrasound sensors

A method and system for correcting a preprogrammed robot end effector path to reduce the kinematic error are developed. The approach used in the method is to mount 3D ultrasound position sensor on the robot end effector and compute 3D Cartesian position of this sensor using 1D range measurements between the senders and an array of ultrasound receivers at fixed, predetermined positions. The method and system allow speedy correction of a robot path with economical usage of computer resources. The method includes steps of sensing and measuring path offsets between the idealized end effector location and the actual location of the manipulator end effector at a plurality of waypoints. Then, after appropriate calculations, the method includes the steps of correcting the coordinates of waypoints within the preprogrammed path, transforming the preprogrammed path coordinates into machine control coordinates, and providing a controller for the robot manipulator with such machine control coordinates. A 3D ultrasound position sensor used in the method provides low-cost, high precision measurements of the Cartesian position of a robot end effector within the robot workspace.