Control system for eyeglass tracer

A control and data acquisition system for a pivotally actuated tracer which traces an object while the object is held in a more-vertical-than-horizontal orientation, said control system comprising:

• a trace control element adapted to apply control signals to said pivotally actuated tracer, which control signals cause an object engager of the tracer to be pivotally actuated against and along the object to be traced with a biasing force toward said object, while the object engager is rotated along the object;
• a gravity compensation element adapted to compensate for the effects of gravity on said object engager by causing said trace control element to apply said control signals in such a way that said tracer exerts a pivoting force on said object engager which varies depending on the rotational orientation of said object engager to keep the biasing force substantially constant along said object, said biasing force being a sum of the pivoting force and a component of gravitational force on said object engager directed toward said object;
• a position monitoring element adapted to detect, while the object engager is rotated, pivot information indicative of how far the object engager has been pivoted and extension information indicative of how far the object engager has been extended from a pivot axis of said tracer, said pivot information and extension information defining polar coordinate information when combined with rotational information indicative of the rotational orientation of the object engager at instances when said pivot information and said extension information are detected;
• and
• a conversion element adapted to convert at least one aspect of said polar coordinate information into cylindrical coordinate information.

A method of tracing an object while the object is held in a more-vertical-than-horizontal orientation, said method comprising the steps of:

• holding the object in a more-vertical-than-horizontal orientation;
• pivotally actuating an object engager against and along the object with a biasing force toward said object, while the object engager is rotated along the object;
• and
• compensating for the effects of gravity on said object engager by exerting a pivoting force on said object engager which varies depending on the rotational orientation of said object engager to keep the biasing force substantially constant along said object, said biasing force being a sum of the pivoting force and a component of gravitational force on said object engager directed toward said object.

A method of acquiring data using a pivotally actuated tracer, comprising the steps of:

• engaging a pivotally mounted object engager of said tracer against an object to be traced;
• rotating said pivotally mounted object engager so that said object engager keeps an object engaging feature thereof engaged against said object;
• detecting, while said pivotally mounted object engager of the tracer is rotated, pivot information indicative of how far the object engager has been pivoted and extension information indicative of how far said object engager has been extended from a pivot axis of said tracer, said pivot information and extension information defining polar coordinate information when combined with rotational information indicative of the rotational orientation of the object engager at instances when said pivot information and said extension information are detected;
• and
• converting at least one aspect of said polar coordinate information into cylindrical coordinate information.