Active deployment system and method

Abstract

The active deployment system ( 10, 10 ′) comprises a passive cylinder system ( 410 ) coupled with an active cylinder system ( 400 ). The passive cylinder system ( 410 ) including a pre-charged accumulator ( 440 ), provides load balance for the equipment or other mass/load being deployed. Pressure provided to the blind end of the passive cylinder supports the load ( 60 ), such that the passive cylinder is balanced mid-stroke with the load hanging from a cable ( 30 ). A sheave arrangement ( 120, 130 ), placed at opposite ends of the passive cylinder-active cylinder combination, is used to introduce a line travel multiplier for cylinder displacement. The active cylinder is controlled hydraulically to add or remove load to/from the passive cylinder system in order to provide a compensating balance. The method comprises the steps of measuring a heave movement (velocity and direction), and adjusting the tension force applied to the cable ( 30 ) upon determining that the heave velocity exceeds a pre-selected critical velocity.

What is claimed is:  
     
         1 . An active deployment system for regulating a distance between a mass and a destination point, wherein the mass is suspended above the destination point from a distal end of a cable attached to a moving platform at a proximal end of the cable, the system comprising: 
 a cable tensioner in reeved engagement with the proximal end of the cable and in mechanical engagement with the moving platform, wherein the cable tensioner includes a rod assembly adapted to apply a tension force to the cable under heaving conditions;    an accelerometer for providing a heave movement signal in proportion to a heave distance of the moving platform;    a stroke sensor for providing a feedback motion signal in proportion to a movement distance of the rod assembly; and    a processing means in electrical communication with the cable tensioner, the accelerometer, and the stroke sensor, wherein the processing means is adapted to monitor the platform movement signal and the feedback motion signal, and to regulate the distance by adjusting the tension force applied to the cable.    
     
     
         2 . The active deployment system of  claim 1 , wherein the cable tensioner comprises a passive cylinder including a passive cylinder rod and an active cylinder including an active cylinder piston, and wherein the passive cylinder rod is attached to the active cylinder piston to form a rod assembly.  
     
     
         3 . The active deployment system of  claim 2 , wherein the passive cylinder system is pre-charged with air to a mid-stroke position of the passive cylinder rod so as to suspend the mass at the distance.  
     
     
         4 . The active deployment system of  claim 3 , wherein the tension force applied to the cable is adjusted by moving the rod assembly in opposite proportion to the heave movement signal.  
     
     
         5 . The active deployment system of  claim 4 , wherein the heave movement signal includes a heave velocity.  
     
     
         6 . The active deployment system of  claim 5 , wherein the heave movement signal includes a heave direction.  
     
     
         7 . A method for regulating a distance between a mass and a destination point, wherein the mass is suspended above the destination point from a distal end of a cable in reeved engagement a cable tensioner, wherein a proximal end of the cable is in mechanical engagement with a moving platform, and wherein the cable tensioner includes a rod assembly adapted to apply a tension force to the cable under heaving conditions, comprising the steps of: 
 measuring a heave movement experienced by the moving platform, wherein the heave movement includes a heave velocity and direction; and    adjusting the tension force applied to the cable upon determining that the heave velocity exceeds a preselected critical velocity.    
     
     
         8 . The method of  claim 7 , wherein the step of adjusting the tension force applied to the cable is accomplished by adjusting the rate of at least one fluid flow within the cable tensioner.  
     
     
         9 . The method of  claim 8 , wherein the cable tensioner comprises a passive cylinder including a passive cylinder rod and an active cylinder including an active cylinder piston, wherein the passive cylinder rod is fixedly attached to the active cylinder piston to form the rod assembly, and wherein the at least one fluid flow within the cable tensioner is in fluid communication with the active cylinder.  
     
     
         10 . The method of  claim 9 , including the step of pre-charging the passive cylinder system with air to a mid-stroke position of the passive cylinder rod so as to suspend the mass at the distance.  
     
     
         11 . The method of  claim 7 , wherein the tension force applied to the cable is adjusted by moving the rod assembly in opposite proportion to the heave movement.  
     
     
         12 . The active deployment system of  claim 11 , wherein the heave movement includes a heave velocity, and wherein the tension force applied to the cable is adjusted by moving the rod assembly in opposite proportion to the heave velocity.  
     
     
         13 . The active deployment system of  claim 12 , wherein the heave movement includes a heave direction, and wherein the tension force applied to the cable is adjusted by moving the rod assembly in a direction opposite to the heave direction.