Method and apparatus for sensing position

摘要

An encoding sequence is configured to detect the position and direction of motion of an actuator. The actuator includes at least two members where one of the members moves with respect to the other. Two sets of binary indicators are either affixed to or integrally assembled along one of the members. Each pair of indicators defines a position of the actuator and each binary indicator is configured to identify one of two states, such as a magnetic pole or a graphical mark where each state corresponds to a logical zero or a logical one. The indicators are arranged on the actuator such that at least one of the indicators transitions between one of the two states at each position along the actuator. At least one sensor is provided to detect the state of the binary indicators as the two members of the actuator move with respect to each other.

主权项

1. A system for detecting a position of an actuator having a first member and a second member, the first member axially movable with respect to the second member, the system comprising:
a first set of binary indicators located in a first plane on and axially spaced along the first member of the actuator, wherein each binary indicator defines one bit within a word, the word has a predefined length, and each binary indicator defines a position of the first member with respect to the second member; a second set of binary indicators located in a second plane on and axially spaced along the first member of the actuator, wherein the second plane is generally parallel to the first plane and each of the binary indicators in the second set corresponds to one of the binary indicators in the first set; at least one sensor radially spaced from the first actuator and configured to generate a first signal corresponding to the state of the first set of binary indicators and to generate a second signal corresponding to the state of the second set of binary indicators; and a logic circuit configured to receive each of the signals corresponding to the state of the first and second set of binary indicators and to detect the position of the first member of the actuator with respect to the second member.