Precise transport positioning apparatus using a closed loop controlled, non-direct drive or friction drive system with absolute positioning encoder

Abstract

An apparatus for positioning a workpiece carrier with respect to a workstation can include an encoder reader located in a fixed position at a workstation for generating a signal in response to interaction with at least one encoder strip, a workpiece carrier movable along a path of travel through the workstation, and having an encoder strip connected thereto, the encoder strip operably interacting with the encoder reader located at the workstation, and a non-direct drive or friction drive engaging the workpiece carrier for moving the carrier along the path of travel through the workstation, the non-direct drive or friction drive responsive to the signal from the encoder reader in a closed loop feedback control system. The encoder reader can be selected from a group consisting of an optical encoder reader, a magnetic encoder reader, and any other absolute positioning encoder reader. A closed loop feedback control system can be provided for receiving the signal from the encoder reader, and for generating an output signal in response to the signal from the encoder reader in accordance with a program stored in memory. The encoder reader can be used for generating a signal corresponding to at least one of a position identification signal, a workpiece carrier identification signal, and a workpiece configuration identification signal.