Direct sensing system for a spherical joint

A work machine, comprising:

• a frame,
• an engine arranged on the frame and configured for powering the work machine;
• a wheel system secured to the fame;
• and
• a steering system for turning a pair wheels of the wheel system, the steering system comprising a linkage system for controlling the relative amount of turning of the pair of wheels and including a hydraulic cylinder pivotally secured to a steering arm with a spherical ball joint, the ball joint having a head of a ball stud arranged in a cylinder eye with a bearing;
• and
• a direct sensing system for measuring the relative rotation of the ball stud about the longitudinal axis of the ball stud, the direct sensing system comprising:
• an anchor secured within the ball stud of the spherical joint;
• a rotational tie having a first end and a second end, the first end being secured to the anchor to hold the first end parallel to a longitudinal axis of the ball stud;
• a rotation sensor comprising:
• a sensor target rotationally coupled to the second end of the rotational tie and secured for free rotation relative to the cylinder eye of the spherical joint;
• and
• an angle sensor configured and arranged to sense a changing angle of the sensor target.

A device for measuring rotation of a joint about a selected axis, comprising:

• a rotational tie that is flexible about two lateral extending axes and rotationally rigid about a longitudinal axis, the rotational tie having a first end and a second end, the first end being configured for securing to a rotating portion of the joint at an anchor point and parallel to the selected axis;
• a rotation sensor comprising:
• a sensor target rotationally coupled to the second end of the rotational tie and configured for securing for free rotation to a framework of the joint;
• and
• an angle sensor configured for arrangement on the framework of the joint and configured to sense a changing angle of the sensor target.