Device and method of motion control

Abstract

A device and method of iterative motion control is described using a non-linear table in a feedback loop to convert a desired acceleration input to motor drive outputs, where the motor is part of a controlled motion system. The table may be a two- or three-dimensional table additionally responsive to the current system state, such as shaft speed, position, or phase angle. The motor may be a two-coil stepper motor where the corrected non-linearity serves the purpose of maintaining desired toque. Inputs may be waypoints comprising both a target position and target velocity. The motion system may use an inverted SCARA arm. Up to three non-linear correction tables may be used: a first corrects motor steps to a more accurate shaft angle; a second corrects motor drive signals to achieve desired torque; a third correct motor drive signals responsive to shaft speed. Tables may be generated by a series of motion passes using a fixed shaft offset angle for each pass.