Capstan assembly and control system

Abstract

A method and apparatus for precisely controlling the tension of a cabling assembly is described. The control loop includes a triple-feedback-loop to allow the manufacture of a large number of cable pairs. The control loop may be used with any take-up and payoff assemblies and compensate for wide variations in take-up reel weight, cable weight, process line speeds, and pay-off tension. One of the loops of the triple-feedback-loop is under-damped and unstable and allows the control loop to compensate for the wide variations without changing control systems or cabling apparatus.

What is claimed is:  
     
         1 . A cabling control system comprising: 
 a first cabling control loop, a second cabling control loop, and a third cabling control loop.    
     
     
         2 . The system of  claim 1 , where the first cabling control loop comprises an underdamped unstable control loop.  
     
     
         3 . The system of  claim 2 , wherein the unstable control loop comprises a first feedback loop monitoring a take-up reel motor armature current.  
     
     
         4 . The system of  claim 3 , wherein the first feedback loop compensates for variations in take-up reel weight during cabling operation.  
     
     
         5 . The system of  claim 4 , wherein the first feedback loop compensates for dancer tension imbalances while processing up to about 600 pair cable configurations.  
     
     
         6 . The system of  claim 5 , wherein the first feedback loop compensates for dancer tension imbalances while processing up to about 100 pair of cable configurations.  
     
     
         7 . The system of  claim 2 , wherein the second cabling control loop comprises a neutrally stable control loop.  
     
     
         8 . The system of  claim 7 , wherein the neutrally stable control loop is critically damped to slightly underdamped.  
     
     
         9 . The system of  claim 7 , wherein the neutrally stable control loop comprises a second feedback loop and monitors take-up reel drive motor speed.  
     
     
         10 . The system of  claim 7 , wherein the neutrally stable control loop comprises a second feedback loop and compensates for variations in line speed or take-up reel speed, or both, during cabling operation.  
     
     
         11 . The system of  claim 7 , wherein the third cabling control loop comprises a stable control loop.  
     
     
         12 . The system of  claim 11 , wherein the third stable control loop is overdamped.  
     
     
         13 . The system of  claim 12 , wherein the third stable control loop comprises a third feedback loop that monitors and compensates for changes in dancer position.  
     
     
         14 . The system of  claim 11 , wherein the overall loop damping ratio is approximately 0.74 across all combinations or variations in reel weight, reel fill, and line speed.  
     
     
         15 . The system of  claim 1 , further comprising a capstan and dancer assembly coupled to the first, second, and third control loops.  
     
     
         16 . The system of  claim 15 , further comprising a plurality of capstan and dancer assemblies coupled to the first, second, and third control loops.  
     
     
         17 . A cabling assembly comprising: 
 a frame;    a capstan drum assembly supported by the frame;    a drum drive motor coupled to the drum assembly;    a dancer assembly spaced from the capstan drum assembly;    a take-up reel; and    a triple-loop control system for controlling cabling from the capstan drum assembly to the take-up reel.    
     
     
         18 . The assembly of  claim 17 , further comprising a pneumatic cylinder for maintaining a constant tension on cables between the drum assembly and the dancer assembly.  
     
     
         19 . The assembly of  claim 18 , further comprising a linear potentiometer for monitoring the position of the dancer assembly.  
     
     
         20 . The assembly of  claim 17 , wherein the capstan and dancer assemblies contain up to twenty-five cable pairs.  
     
     
         21 . The assembly of  claim 20 , wherein the triple-loop control system comprises a controller having an underdamped first feedback loop.  
     
     
         22 . The assembly of  claim 21 , wherein the underdamped first feedback loop is programmed to monitor take-up reel motor armature current and compensate for variations in take-up reel weight.  
     
     
         23 . The assembly of  claim 21 , wherein the triple-loop control system further comprises a second critically damped-to-underdamped feedback loop programmed to compensate for variations in line speed, take-up reel speed, or both, that arise as the take-up reel fills with cable.  
     
     
         24 . The assembly of  claim 23 , wherein the triple-loop control system further comprises a third overdamped feedback loop programmed to compensate for variations in dancer assembly position.  
     
     
         25 . A capstan apparatus comprising: 
 a take-off reel assembly supported by a frame;    a take-off reel drive motor coupled to the take-off reel assembly and adapted to provide a supply of wire pairs at a constant rate;    a dancer assembly spaced from the take-off reel assembly and adapted to receive the supply of wire pairs at the constant rate;    a pay-off reel; and    a capstan controller comprising a triple-loop feedback system for controlling cabling from the take-off reel assembly to the pay-off reel.    
     
     
         26 . The apparatus of  claim 25 , wherein the triple-loop feedback system comprises an underdamped first feedback loop.  
     
     
         27 . The apparatus of  claim 26 , wherein the underdamped first feedback loop is programmed to monitor pay-off reel motor armature current.  
     
     
         28 . The apparatus of  claim 25 , further comprising a programmable logic controller for programming and controlling the capstan controller.  
     
     
         29 . The apparatus of  claim 28 , further comprising a user interface coupled to the programmable logic controller.  
     
     
         30 . The apparatus of  claim 25 , further comprising one or more additional slave capstan controllers controlling one or more additional capstan apparatuses.  
     
     
         31 . The apparatus of  claim 25 , further comprising a safety functions interface programmed to monitor one or more capstan apparatus parameters and shut down the capstan apparatus when the one or more parameters reach a predetermined threshold.  
     
     
         32 . The apparatus of  claim 31 , wherein the one or more capstan assembly parameters comprise pay-off reel motor current, feedback signal ranges, time period between changes in feedback signals, position of the dancer assembly, and pay-off reel speed.  
     
     
         33 . A method of controlling cabling equipment comprising applying a triple-loop feedback mechanism to a cabling controller.  
     
     
         34 . The method of  claim 33 , wherein the applying the triple-loop further comprises compensating for weight variations in a take-up reel by feeding back motor armature current of a take-up reel drive motor with an underdamped first feedback loop.  
     
     
         35 . The method of  claim 34 , wherein the applying a triple loop further comprises compensating for cable line speed, take-up reel speed, or both, by feeding back take-up reel motor speed with a neutrally stable second feedback loop.  
     
     
         36 . The method of  claim 35 , wherein the neutrally stable second feedback loop comprises critically damping or slightly underdamping a signal indicative of the take-up reel motor speed.  
     
     
         37 . The method of  claim 35 , wherein the applying a triple loop further comprises compensating for tension differences between a wire input side of a dancer and a wire output side of the dancer by feeding back dancer position with an overdamped third feedback loop.  
     
     
         38 . The method of  claim 33 , further comprising providing an overall loop damping ratio of 0.74 across all combinations of variations in reel weight, reel fill, and line speed.  
     
     
         39 . A method of controlling a cabling assembly comprising providing a triple-loop feedback mechanism.  
     
     
         40 . The method of  claim 39 , further comprising conditioning a first loop of the triple-loop feedback mechanism with an underdamped transfer function.  
     
     
         41 . The method of  claim 40 , wherein the first loop monitors take-up reel motor armature current and compensates for variations in take-up reel weight.  
     
     
         42 . The method of  claim 40 , further comprising conditioning a second loop of the triple-loop feedback mechanism with a critically damped-to-slightly underdamped transfer function.  
     
     
         43 . The method of  claim 42 , wherein the second loop monitors take-up motor speed and compensates for variations in line speed, reel speed, or both as a take-up reel fills with cable.  
     
     
         44 . The method of  claim 42 , further comprising conditioning a third loop of the triple-loop feedback mechanism with an overdamped transfer function.  
     
     
         45 . The method of  claim 44 , wherein the third loop monitors a dancer assembly position and compensates for differences in tension between a wire input side of the dancer and a cable output side of the dancer.  
     
     
         46 . The method of  claim 45 , further comprising applying torque to a take-up reel to balance the differences in tension.  
     
     
         47 . A method of creating a cable comprising: 
 unreeling multiple wires to a dancer assembly at a constant rate;    applying a constant tension to the multiple wires; and    cabling the elements onto a take-up reel;    wherein the constant tension of the elements is precisely controlled by a triple-feedback-loop.    
     
     
         48 . The method of  claim 47 , wherein the triple-feedback loop comprises an underdamped first loop feeding take-up motor armature current back to a controller and compensating for variations in take-up reel weight.  
     
     
         49 . The method of  claim 48 , wherein the triple-feedback loop comprises a critically damped second loop feeding take-up motor speed to the controller and compensating for variations in line speed, reel speed, or both.  
     
     
         50 . The method of  claim 49 , wherein the triple-feedback loop comprises an overdamped third loop feeding dander position to the controller and compensating for differences in tension between a wire input side of the dancer assembly and a wire output side of the dancer assembly.  
     
     
         51 . A cabling assembly comprising: 
 a capstan drum assembly;    a take-up reel; and    a triple-loop control system for controlling cabling from the capstan drum assembly to the take-up reel.    
     
     
         52 . The assembly of  claim 51 , further comprising a pneumatic cylinder for maintaining a constant tension on cables between the capstan drum assembly and a dancer assembly arranged between the capstan drum assembly and the take-up reel.  
     
     
         53 . The assembly of  claim 51 , wherein the triple-loop control system comprises a controller having an underdamped first feedback loop.  
     
     
         54 . The assembly of  claim 53 , wherein the underdamped first feedback loop is programmed to monitor take-up reel motor armature current and compensate for variations in take-up reel weight.