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METHOD AND APPARATUS FOR IMPROVING THE OPERATION OF A REMOTE VIEWING DEVICE BY CHANGING THE CALIBRATION SETTINGS OF ITS
ARTICULATION SERVOS 5
CROSS-REFERENCE TO RELATED
APPLICATIONS
This application claims priority to and is a continuation- 10 in-part of co-pending U.S. patent application Ser. No. 10/768,761 entitled Remote Video Inspection System, filed Jan. 29, 2004, which application is incorporated herein by reference in its entirety.
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FIELD OF THE INVENTION
The invention relates generally to a system and method for improving the operation of a remote viewing device. More particularly the invention relates to changing the 20 calibration settings of the remote viewing device's articulation servos to remove slack in the control cables and/or increase the range of motion of the viewing head.
BACKGROUND 25
Borescopes, endoscopes, fiberscopes and the like (herein after generally referred to as remote viewing devices) are widely used to provide visual inspection of physically difficult to reach or inhospitable environments. The move- 30 ment of remote viewing devices is frequently controlled by articulation servos that vary the tensions in control cables. The change in tensions in the control cables guides the movement of the remote viewing device's viewing head.
Over the life of a remote viewing device, numerous 35 factors including cable stretch and increased friction and stiffness can lead to imprecise operation and a decrease in the viewing head's range of motion. Some previous industry responses to these problems require that the remote viewing device be disassembled by a specialized technician. This can 40 in turn require that the remote viewing device be returned to the manufacturer for processing.
What is needed is a system that is easily executable by a standard operator to remove cable stretch and increase a viewing head's range of motion. 45
SUMMARY OF THE INVENTION
In one aspect, the invention features a method for improving the operation of a remote viewing device. The method 50 comprises removing at least a portion of slack from at least one control cable attached to a servo motor. The removal of the at least a portion of slack includes at least changing a distance between the servo motor and a flexible tube termination block until a specified tension is encountered in the at 55 least one control cable. The method also comprises fixing the servo motor where the specified tension is encountered and determining a first servo control signal value corresponding to no angular deflection in a viewing head of the remote viewing device. In addition the method comprises 60 increasing the viewing head's range of motion. The process of increasing the viewing head's range of motion includes at least determining a second servo control signal value corresponding to a first angular deflection in the viewing head.
In one embodiment the method further comprises deter- 65 mining a third servo control signal value corresponding to a second angular deflection in the viewing head of the remote
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viewing device. In another embodiment the method further comprises storing the value of the first and second servo control signal values in a memory of a control unit of the remote viewing device. In an additional embodiment, the method further comprises placing a recalibration cap over the viewing head in a first position, wherein the recalibration cap in the first position fixes the viewing head in a nondeflected position. In a further embodiment, determining a second servo control signal value includes: placing a recalibration cap over the viewing head in a second position, wherein the recalibration cap in the second position allows the viewing head to deflect a first number of degrees; and rotating the viewing head a first number of degrees until it is in contact with the recalibration cap. In yet another embodiment, the method further includes rotating the viewing head until imaging optics in the viewing head view a predetermined target.
In yet an additional embodiment, the method further comprises placing a first recalibration cap over the viewing head, wherein the first recalibration cap fixes the viewing head in a non-deflected position. In yet a further embodiment, the determining a second servo control signal value includes: placing a second recalibration cap over the viewing head, wherein the second recalibration cap allows the viewing head to deflect a first number of degrees; and rotating the viewing head the first number of degrees until it is in contact with the second recalibration cap. In still another embodiment, the first and second servo control signal values are used to recalibrate the operation of the remote viewing device to increase the viewing head's range of motion.
In still an additional embodiment, the recalibration includes changing a stroke of and/or a force applied by the servo motor. In still a further embodiment, the method further comprises determining an extrapolated servo control signal value for an arbitrary deflection in the viewing head, the determining the extrapolated servo control signal value using at least the first and second servo control signal values. In still yet another embodiment, the at least one control cable is a plurality of control cables and the determining a first servo control signal value that corresponds to no angular deflection in the viewing head of the remote viewing device includes at least equalizing tensions in the plurality of control cables. In still yet an additional embodiment, the remote viewing device is one of: a borescope, a fiberscope, or an endoscope.
In another aspect, the invention features a system for improving the operation of a remote viewing device. The method comprises a remote viewing device control unit; a remote viewing device viewing head; a remote viewing device flexible tube connected at a proximal end to the control unit and at the distal end to the viewing head; and at least one servo motor located in the control unit and connected to at least one control cable that passes through the flexible tube and is attached to the viewing head, a distance between the at least one servo motor and a flexible tube termination block capable of being varied to remove at least a portion of slack in the at least one control cable.
In one embodiment, the system comprises at least one servo motor support rail attached to a support structure in the remote viewing device control unit; a spring connected to the support structure and the at least one servo motor; a top groove plate attached to the at least one servo motor; and a bottom groove plate coupled to an engagement screw, wherein the engagement screw engages and disengages the top and bottom groove plates such that when the top and bottom groove plates are engaged the at least one servo
