Positioning using a position sensor and a calibrated offset between the position sensor and a reference position
AssigneeHewlett-Packard Company
InventorsMichael P. Eland, Kevin L. Miller
Life of this patent
Estimating the term…
Abstract
A transducer position sensing system, in a electromechanical drive, for determining transducer position. A sensor is mounted with a non-adjustable position and without absolute position accuracy, thereby lowering manufacturing costs. The position of the transducer at which the sensor switches states is accurately determined in a manufacturing test fixture and recorded in a permanent memory used by a drive controller. The drive controller can then accurately determine transducer position during subsequent initialization procedures.
Claims12
A position sensor system for an object, the position sensor system comprising:
- a controller for moving the object;
- a sensor, having first and second states, mounted so that as the object is moved by the controller to the sensor, the movement of the object causes the sensor to switch from the first state to the second state;
- and
- a memory device, readable by the controller, containing a numerical value, the numerical value indicative of a position of the object relative to a reference position when the sensor switches from the first state to the second state, the numerical value having been previously accurately determined, the position of the sensor relative to the reference position being unknown before determination of the numerical value, thereby enabling the position of the object relative to the reference position to be accurately known.
A method for calibrating a position sensor for an object, the method comprising the following steps:
- a. moving the object with a controller;
- b. sensing when the sensor switches from a first state to a second state, the position of the sensor relative to a reference position being unknown;
- c. measuring the position of the object relative to the reference position with a precision calibration fixture when the sensor switches from the first state to the second state;
- and
- d. recording the position of the object in a memory device readable by the controller, thereby enabling the position of the object relative to the reference position to be accurately known.
A method for precisely determining a position of an object relative to a reference position, the method comprising the following steps:
- (a) moving the object with a controller, to a position sensor;
- (b) sensing, by the controller, when the position sensor switches from a first state to a second state;
- (c) reading, by the controller, a position value from a memory, the position value having been previously determined as the precise position of the object relative to a reference position when the position sensor switches from the first state to the second state, the position of the position sensor relative to the reference position being unknown before determination of the position value;
- and
- (d) determining, by the controller, from the position value, a precise position of the object relative to the reference position.
Dependencies are inferred from the claim text.