On an accuracy problem of robot manipulators

The problem of robot accuracy is studied. Based on a developed error model [1, 2, 3] describing the accuracy of a robot manipulator resulting from kinematic errors, a statistical analysis is performed to obtain an estimation to the robot accuracy which is measured in terms of the covariance matrix of the Cartesian errors of the end-effector. We derive the maximum likelihood estimate for this covariance matrix. The presented estimate entails a measurement of Cartesian errors at many different arm positions in the known world, without actually dealing with individual kinematic errors.