Apparatus and method for position encoding

摘要

A transfer case motor controls the rotation of a cam. The cam actuates various gear states of a transfer case of a four-wheel-drive vehicle. A contact plate rotates with the cam and encodes the position of the cam as a four-bit binary code. The code is such that when the cam travels between any two gear states, one bit of the four-bit code stays constant from the initial gear state until the final gear state is reached. The single bit can thus be observed to determine that the final gear state has been reached. The encoding scheme is also such that the bit which stays constant always assumes the same state.