Abstract: A method for measuring a large shaft rotation angle utilizes one or more cams attached to the shaft. Each cam shape is designed to have one or more detectable harmonics when rotated. Multiple harmonics in a single cam or amongst multiple cams may have a particular order. Pairs of fine position sensors, positioned at opposing sense angle positions relative to the cam(s) measure displacement of the cam during rotation. The data from the position sensors is then analyzed, with a processor, to determine the large shaft rotation angle and angular displacement relative to an ideal axis of rotation.

Abstract: A method, executed by one or more computers, for unwrapping phase wrapped data including a plurality of nodes. The method includes: selecting a root node from the plurality of nodes to start unwrapping (102); selecting next nodes to be unwrapped, from the neighbor nodes of the root node; dynamically calculating a confidence factor for each node being unwrapped (104); when a closed loop wherein one node can be unwrapped from either of two previously unwrapped nodes is encountered and an unwrapped value predicted by each of the prior nodes of the two nodes are different during unwrapping, comparing calculated confidence factors for the two previously unwrapped nodes (106); using the compared confidence factors of the two previously unwrapped nodes to determine which one of the two nodes is an erroneous node (108); and reprocessing the erroneous node to correct a previous unwrapping error (112).

Abstract: A method for measuring a large shaft rotation angle utilizes one or more cams attached to the shaft. Each cam shape is designed to have one or more detectable harmonics when rotated. Multiple harmonics in a single cam or amongst multiple cams may have a particular order. Pairs of fine position sensors, positioned at opposing sense angle positions relative to the cam(s) measure displacement of the cam during rotation. The data from the position sensors is then analyzed, with a processor, to determine the large shaft rotation angle and angular displacement relative to an ideal axis of rotation.

Abstract: A method, executed by one or more computers, for unwrapping phase wrapped data including a plurality of nodes. The method includes: selecting a root node from the plurality of nodes to start unwrapping (102); selecting next nodes to be unwrapped, from the neighbor nodes of the root node; dynamically calculating a confidence factor for each node being unwrapped (104); when a closed loop wherein one node can be unwrapped from either of two previously unwrapped nodes is encountered and an unwrapped value predicted by each of the prior nodes of the two nodes are different during unwrapping, comparing calculated confidence factors for the two previously unwrapped nodes (106); using the compared confidence factors of the two previously unwrapped nodes to determine which one of the two nodes is an erroneous node (108); and reprocessing the erroneous node to correct a previous unwrapping error (112).