Patent Publication Number: US-9404718-B1

Title: Multi-shot disrupter apparatus and firing method

Description:
ACKNOWLEDGEMENT OF SUPPORT AND DISCLAIMER 
     This material is based upon work supported by the United States Army under Contract No. W15QKN-12-C-0005. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the Army. 
    
    
     BACKGROUND 
     The present invention generally relates to the field of explosive ordinance disposal, and more particularly to an apparatus and method for disrupting explosive devices allowing multiple shots delivered in an arbitrary order at the discretion of the user. 
     Disrupters are typically used by law enforcement and military personnel to disable explosive devices. Disrupters often operate by driving a projectile, such as water or a solid projectile, which penetrates or otherwise disrupts an explosive device without detonating the explosive. A variety of projectile-based disrupter designs have been created to address the unique dangers of the operating environment. For example, disrupters are often designed to be operable by personnel located at a safe standoff distance from a suspected explosive device. Other designs focus on improving performance or ease of use by adding features such as recoil mitigation, disposable components, light material construction, or enhanced projectile design. However, prior art designs do not adequately provide multi-shot disruption capability to an operator, particularly when the operator is located at a safe standoff distance from the explosive device. 
     Law enforcement and military personnel encounter explosive devices located in vehicles or within concealing packaging. Multiple disrupter shots are often necessary to access and disable such devices, requiring bulky multiple disrupter barrels or single-shot disrupter reloading. Size and weight constraints of robotic mounts limit the usefulness of prior art designs employing multiple barrels. Prior art single-shot devices, requiring manual loading by operators between disrupter shots, cause operational delay. For robot-mounted disrupter operations, the robot must return the single-shot disrupter to personnel at the safe standoff distance for reloading between each disrupter shot, causing additional delay. Further, the operator may desire to use different cartridge load and projectile combinations for specific shots in a single operation, requiring multiple disrupters or disrupter reconfiguration. Deploying multiple disrupters in such cases can be cost-prohibitive. Disrupter reloading and reconfiguration in such cases can be time-prohibitive. 
     SUMMARY 
     The present invention provides a method and apparatus that allows firing of a plurality of disrupter loads in arbitrary order at the discretion of the user. Embodiments of the invention set forth in the accompanying drawings and description integrate design features to address multi-shot operation in common explosive device disruption operational conditions, including remote operation of the disrupter from a robotic mount. These embodiments provide mechanized multi-shot firing capability of stored ammunition cartridges in any desired sequence without loading the magazine in any particular pre-determined order—allowing the user to repeatedly engage one or more targets using customized loads without the operational delay of robot return and manual reloading. Other features and advantages of the invention will be apparent from the description, drawings and claims. 
     In the first exemplary embodiment of the apparatus, a multi-shot disrupter comprising a barrel, firing chamber, breech plate, magazine, feeder, firing mechanism, and control system is disclosed. The magazine stores at least two ammunition cartridges and moves to align the ammunition cartridges with the firing chamber. Additionally, the magazine design provides storage for ammunition cartridges of varying length, non-ammunition accessories such as targeting devices and rangefinders, and blank-propelled projectiles. A feeder loads aligned ammunition cartridges into the firing chamber. The independent movement of the magazine and feeder allows loading of ammunition cartridges from the magazine into the firing chamber in any arbitrary order as selected by the user. The firing mechanism initiates a selected and loaded ammunition cartridge charge. The breech plate and firing chamber direct the thrust of ammunition cartridge propellant gas during firing while the barrel guides a projectile toward a target. A control system is incorporated to facilitate mechanized control of the multi-shot disrupter. In some embodiments, the control system includes at least one feedback sensor, a user interface, a command interpreter, a command sequencer, and a command execution system. The control system facilitates remote operation of the multi-shot disrupter by the user. In some embodiments, such as those firing cased ammunition, an extractor provides mechanized removal of ammunition cartridges from the firing chamber by a remotely located user. 
     In an alternate embodiment of the apparatus, a plurality of firing chambers provide storage and arbitrary-order barrel bore alignment of ammunition cartridges while the independent movement of the firing mechanism initiates the ammunition cartridges in any arbitrary order as selected by the user. 
     In another exemplary embodiment of the apparatus, the multi-shot disrupter is adapted to load and discharge fluid projectiles. During filling operations, fluid driven by a pump flows from a fluid reservoir through a fluid-tight filling conduit and the second seal plug into the barrel bore. As fluid enters the barrel bore, a first seal plug advances along the barrel bore to create a fluid pocket within the bore for use as a projectile. This embodiment allows mechanized breech loading of fluid projectiles. Fluid projectiles are preferred in many disrupter operations. 
     In a further exemplary embodiment of the apparatus, a recoil system is incorporated to adapt the multi-shot disrupter for use in situations where trunnion force applied to the mount must be limited. During firing, recoil momentum is imparted to the disrupter in the opposite direction of projectile momentum. Recoil force and kinetic energy can damage the disruptor or mount if not reduced or absorbed through design considerations. The recoil system disclosed includes a motion guide and a dissipator system. The motion guide directs the recoil kinetic energy of the firing disrupter into a dissipator system, which acts to absorb the recoil kinetic energy generated during disrupter firing. Some embodiments incorporate a return-to-battery system. Following recoil absorption, the return-to-battery system prepares the dissipator system for subsequent firings. These components also reduce recoil momentum and kinetic energy through mass-efficient apportionment. By apportioning a maximized fraction of the allowed total mass of the disrupter and recoil system into the recoiling mass and minimizing the fraction of the non-recoiling fixed mass, the recoil system reduces the initial kinetic energy imparted by the firing process. The disclosed recoil system embodiment facilitates use of high-velocity slug loads and high-mass water loads in robot-mounted disruptor operations, and allows implementation of disrupter design changes without affecting the overall recoil profile so long as the original multi-shot disrupter mass is maintained. 
     In another exemplary embodiment of the apparatus, a sighting device is incorporated to facilitate aiming of the multi-shot disrupter. The sighting device is adapted to provide a targeting beam that is parallel to and can be coaxial with the barrel bore axis of the multi-shot disrupter. During operation, the targeting beam projected by the sighting device provides accurate alignment of the barrel bore axis with a target by casting a marking light upon the target or point of reference when desired aiming alignment is achieved. In coaxial embodiments, the sighting device can then be mechanically removed from the chamber and replaced with the appropriate projectile and ammunition cartridge, with minimal disturbance of the point of aim. A sighting device placed parallel to the bore can be used to illuminate one or more points of reference near the intended point of impact to ensure that the point of impact does not shift during mechanical loading operations. The sighting device is especially suited to remote robotic platform-mounted multi-shot disrupter operation when an operator located at a safe stand-off distance cannot safely aim the disrupter by manual disrupter positioning. 
     In another exemplary embodiment of the apparatus, a rangefinder is incorporated to improve aiming of projectiles following a non-linear defined trajectory, such as liquid projectiles commonly used in disruptor firing. The rangefinder measures the distance between the multi-shot disrupter and a target. The rangefinder is especially suited to improve the aiming accuracy of remote robotic platform-mounted multi-shot disrupter operation when an operator located at a safe stand-off distance cannot safely aim the disrupter by manual disrupter positioning. The rangefinder may also be used to judge the proper distance between the disrupter muzzle and target surface, in order to assure that the proper projectile energy is delivered to the target, or to protect the disrupter or robotic mount from projectile fragments or target fragments. 
     The method of the present invention relates to mechanized discharging of successive disrupter ammunition cartridges in an arbitrary order as selected by the user. The method of firing comprises the steps of providing a multi-shot disrupter apparatus of the present invention with a barrel, a firing chamber, a breech plate, a magazine; a feeder, a firing mechanism, and a control system; and discharging at least two ammunition cartridges in an arbitrary order selected by the user with the disrupter apparatus. The method further comprises lubricating the ammunition cartridges with molybdenum disulfide, tungsten disulfide, hexagonal boron nitride, graphite, mica, cadmium plating, wax, lanolin, oil, silicone grease, or polytetrafluoroethylene (PFTE) lubricants prior to discharge. The method also includes placement of a collar around the case head of the ammunition cartridges prior to discharge. Lubrication and collaring of ammunition cartridges facilitate post-firing extraction by limiting the adhesion of the case head of the ammunition cartridge with the firing chamber during initiation. 
     The method allows the operator to repeatedly engage one or more targets using appropriate loads and projectiles without manual reloading. The operator may select, chamber and fire any load or projectile type that has been stored in the magazine without pre-determination of the firing sequence, allowing subsequent load and projectile selection tailoring based upon initial firing results. The arbitrary order introduction capability precludes the need to anticipate the required order of fire at the time of magazine loading. Arbitrary introduction of multiple user-selected loads is particularly suited to improve prior art remotely controlled disrupter embodiments. 
     The embodiments of the present invention provide and facilitate explosive device disruption by allowing the firing multiple disrupter loads and projectiles in arbitrary order at the discretion of the user while integrating design features to address remote operation, targeting, ranging, recoil and fluid filling of the disrupter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective representation of the multi-shot disrupter. 
         FIG. 2  is a partial sectional view of the multi-shot disrupter taken along lines A-A′. 
         FIG. 3A  is a perspective representation of the rotary breech plate in the open position. 
         FIG. 3B  is a perspective representation of the rotary breech plate in the lock position. 
         FIG. 4  is a perspective representation of the rotary magazine. 
         FIG. 5A  is a perspective representation of the electromechanically-energized spring driven percussive striker. 
         FIGS. 5B, 5C, and 5D  are partial section views of the electromechanically-energized spring driven percussive striker. 
         FIG. 6  is a block diagram schematic of the control system. 
         FIG. 7A  is a perspective representation of the fluid filling system. 
         FIG. 7B  is a side view representation of the fluid filling system in partial sectional view. 
         FIG. 8A  is a perspective representation of the recoil system. 
         FIG. 8B  is a perspective representation of the preferred embodiment of the recoil system. 
         FIG. 9  is a perspective representation of the target designation system coaxial with a barrel in partial sectional view. 
         FIG. 10  is a perspective representation of a multi-shot disrupter embodiment with a range measurement system. 
         FIG. 11  illustrates an example method according to embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A method and apparatus for firing a plurality of disrupter loads in arbitrary order at the discretion of the user is disclosed. Embodiments of the invention set forth in the accompanying drawings and description integrate design features to address multi-shot operation in common explosive device disruption operational conditions, such as remote operation of the disrupter and robotic mount limitations. 
       FIG. 1  shows an embodiment of the multi-shot disrupter.  FIG. 2  shows another embodiment of the multi-shot disrupter in partial section. 
     The barrel is a tubular pressure vessel which guides a projectile toward a target along a bore. The barrel  10  has a forward muzzle end  15  and a rearward end  20 , shown in  FIG. 2 . The barrel is constructed of materials with adequate heat capacity, thermal conductivity, material strength, gas erosion resistance and wear resistance to withstand the high pressures characteristic of desired disrupter cartridges. A high-grade stainless steel alloy is used in some embodiments. In other embodiments where low barrel mass is preferred, an alternate material such as a titanium alloy may be used. A composite material, such as a carbon fiber material, may be used to reinforce a metallic core to construct a barrel that is strong and low-mass. Barrel wall thickness and bore design are selected based on disrupter ammunition loads and projectile types desired by the user. The bore may have a smooth cylindrical surface, or a rifled surface to impart spin to the projectile during firing. In the preferred embodiment, the barrel is removable and interchangeable to facilitate replacement and use of a wide variety of load types. The embodiment in  FIG. 2  depicts a single barrel version, which is preferred to reduce system weight, but multiple barrels could be used to enable multiple shots to be fired in quick succession or to add redundancy for reliability. 
     The firing chamber contains the propellant gas pressure of an ammunition cartridge charge and directs this pressure to force a projectile toward the forward muzzle end of the barrel. The firing chamber wall thickness and design are selected based on disrupter ammunition loads and projectile types desired. The firing chamber is constructed of materials of adequate heat capacity, thermal conductivity, material strength, gas erosion resistance and wear resistance to withstand the chamber pressure curve of the desired ammunition load. 
     A single firing chamber  25  integrated with the barrel structure and coaxial with the barrel bore axis is shown in  FIG. 2 . However, alternate designs could include multiple firing chambers, either embodied as separate structures or integrated within a magazine. In the preferred embodiment, the chamber is integral to the barrel structure to provide a robust chamber-to-bore gas seal. A single chamber is also preferable over multi-chamber embodiments in weight-restricted operating environments such as robot mounts. 
     The firing chamber  25  of  FIG. 2  has a forward end  30  and a rearward end  35 . The bore at the rearward end  20  of the barrel abuts the firing chamber forward end  30 . In the  FIG. 2  embodiment, a forcing cone situated at the firing chamber forward end  30  forms a transition between the firing chamber  25  and the bore of the barrel for shotgun-type ammunition cartridge use, such as 12-gauge ammunition. However, a forcing cone may be unnecessary in embodiments using other types of disrupter ammunition, such as 0.45 Automatic Colt Pistol ammunition. 
     The breech plate blocks the firing chamber to resist and direct the thrust of propellant gas during firing of an ammunition cartridge. Referring to  FIG. 2 , the breech plate  45  moves in communication with a mount  48  to block the rearward end of the firing chamber after loading of an ammunition cartridge. The breech plate accommodates initiation of a loaded ammunition cartridge while it blocks the firing chamber. The movement about the mount  48  allows repositioning of the breech plate to open the firing chamber during ammunition cartridge loading and extraction operations. 
     The breech plate embodiment detailed in  FIG. 3A  in the open position, includes a rotary block breech plate  45  which rotates about a second axis parallel to the barrel bore axis and coaxial with the axle bearing surface  49  of the mount. The rotary block design allows the breech plate  45  to rotate to a position in line with the barrel bore axis to block the firing chamber rearward end during firing, as shown in  FIG. 3B . A firing pin passage  47  in the breech plate  45  allows initiation of ammunition cartridges seated in the blocked firing chamber. The breech plate  45  rotates along the bearing surface  49  of the mount to allow ammunition cartridge loading and accessory placement in the firing chamber. 
     The rotary block illustrated in  FIGS. 3A and 3B  uses a breech plate  45  that rotates in a plane perpendicular to the axis of the barrel bore about a fixed axle frame. The axis of the fixed axle frame is parallel to the axis of the barrel bore. In the preferred embodiment, the breech plate  45  can rotate clockwise or counterclockwise through full 360-degree continuous rotation. Other locking system embodiments incorporate alternate mechanisms for positioning the breech plate with respect to the firing chamber including: a falling block, tilting block, rolling block, hinged block, threaded bolt block, interrupted threaded bolt block, a Ferguson bolt block, or rotary lugged bolt block. These alternative embodiments of the breech plate  45  are represented in  FIG. 1  by the box labeled  450 . 
     In a falling block embodiment, the breech plate translates linearly along a plane substantially perpendicular to the barrel bore axis to block and open the firing chamber. 
     In a tilting block embodiment, the breech plate tilts about an axis perpendicular to the barrel bore axis to block and open the firing chamber. 
     In a rolling block embodiment, the breech plate rotates about an axis perpendicular to and intersecting the barrel bore axis to block and open the firing chamber. 
     In a hinged block embodiment, the breech plate tilts through less than 360-degrees of continuous rotation about an axis parallel to the barrel bore axis to block and open the firing chamber. 
     In a threaded bolt block embodiment, the breech plate is attached to a helically threaded portion which screws into receiving threads oriented coaxially to the barrel bore axis to block and open the firing chamber. 
     In a Ferguson bolt block, a breech plate is attached to a helically threaded portion which screws into receiving threads oriented on an axis perpendicular to the barrel bore axis to block and open the firing chamber. 
     In an interrupted threaded block embodiment, the breech plate moves in a combination linear sliding and rotating engaging motion to block and open the firing chamber. The breech plate is attached to an interrupted thread which slides linearly into matching interrupted receiving threads on an axis coaxial to the barrel bore axis. Upon rotation, the breech plate threads engage the receiving threads to block the firing chamber. 
     In a rotary lugged bolt block embodiment, the breech plate moves in a sequential combination linear sliding and rotating engaging motion to block and open the firing chamber. The breech plate slides linearly on an axis coaxial with the barrel bore axis. Upon rotation, one or more locking lugs engage the receiver to block the firing chamber. 
     In the preferred embodiment, the magazine and feeder move independently to feed stored ammunition cartridges into the firing chamber. The magazine is capable of containing at least two ammunition cartridges. The magazine moves with respect to the firing chamber and brings the ammunition cartridges into alignment with the barrel bore axis in any arbitrary order as selected by the user. The feeder introduces aligned ammunition cartridges into the firing chamber through movement independent of the magazine, allowing arbitrary order introduction of any aligned ammunition cartridge into the firing chamber. This arbitrary order introduction capability allows the user to select subsequent ammunition cartridges in any desired sequence based on prior shot outcomes without loading the magazine in any particular order. The arbitrary introduction of multiple user-selected loads is particularly advantageous over the prior art for remotely controlled disrupter embodiments because robotic return and manual loading steps are eliminated. 
       FIG. 1  includes a rotary magazine  55 . The rotary magazine, detailed in  FIG. 4 , is adapted to store multiple ammunition cartridges in storage cavities  56 . The embodiment of  FIG. 4  depicts eight storage cavities  56 ; however, other numbers allowing for storage of at least two ammunition cartridges could be used. The storage cavities in the preferred embodiment accommodate a variety of ammunition types differing in projectile composition, propellant type, casing geometry, or casing material, for example. 
     The storage cavities  56  can also be adapted to store non-ammunition accessories and non-cased projectiles. Non-ammunition accessories include bore sight modules, lamps, cameras, audio sensors, chemical sensors, transponders, signal lamps, flares and strobes. Non-cased projectiles lack integrated firing primers and propellant charges. Non-cased projectiles include blank-fired projectiles, pneumatically launched projectiles, darts, spooled cables, and wires. 
     The rotary magazine  55  embodiment of  FIG. 2  is movably mounted to rotate on a second axis parallel to the barrel bore axis. Storage cavities containing ammunition cartridges, accessories, and non-cased projectiles rotate about the second axis to align a user-selected cavity with the barrel bore axis. Although a rotary magazine is shown, a linear magazine movably mounted to align user-selected ammunition cartridges with the barrel bore axis by means of a linear translation motion substantially perpendicular to the barrel bore axis could also be used. This alternative embodiment of the magazine  55  is represented in  FIG. 1  by the box labeled  550 . 
     The feeder  60  embodiment of  FIG. 2  contains a multi-function end effector  61  attached to a linear actuator  62 . This feeder  60  is positioned coaxial to the barrel bore axis and introduces an aligned ammunition cartridge into the firing chamber  25  by means of a threaded drive of the linear actuator  62 . The independent movement of the magazine  55  with respect to the feeder  60  allows introduction of ammunition cartridges into the firing chamber  25  in an arbitrary order selected by the user. The chambering order is not pre-determined by the order that the ammunition cartridges were placed into storage cavities of the magazine, unlike magazines which feed the chamber sequentially according to the order or reversed order of initial magazine loading. The ability to fire different cartridges in any desired order is advantageous because different cartridge types serve different functions. The most appropriate initial shot type may not be known until a remote assessment is made using robotic sensors. The most appropriate follow-on shot type may not be known in advance, until the outcome effectiveness of a previous shot can be judged by the operator. 
     The firing mechanism initiates the propellant charge of an ammunition cartridge positioned in the firing chamber. The firing mechanism  65  embodied in  FIG. 2  is an electromechanically-energized spring driven percussive striker adapted to rotate with the magazine  55  and to align in a position coaxial with the barrel bore axis during firing.  FIGS. 5A, 5B, 5C and 5D  detail the electromechanically-energized spring driven percussive striker embodiment. As shown in  FIGS. 5B, 5C, and 5D , a mainspring  67  in communication with a striker body  68  drives a firing pin  66  with respect to a housing  69 . In this embodiment, the feeder engages and withdraws the striker body  68  against the force of the mainspring  67 . To fire, the striker body is released from the feeder causing the energy stored in the mainspring to plunge the firing pin through the firing pin passage  47  of the locking system  45  to initiate an ammunition cartridge seated in the firing chamber. In the preferred embodiment, the firing pin is physically distinct from the striker body and biased rearward by a spring  64 . This allows the firing pin  66  to have lower mass and inertia, which reduces the chance of unintentional fire in the event of external mechanical shocks or drops. 
     Other firing mechanism embodiments initiate the chambered ammunition cartridge through alternate energetic means. Several alternative firing mechanism embodiments are described below and are represented in  FIG. 2  by the box labeled  650 . In an electrokinetic percussive striker system embodiment, energy from an electrical source, such as a battery or capacitor, is transformed directly into kinetic energy of a percussive striker without intermediate energy storage in a mainspring, for example, by means of current flow through a solenoid which drives a magnetic body in communication with the percussive striker. The percussive striker initiates an ammunition cartridge seated in the firing chamber. 
     In an electrothermal ignition system embodiment, an electrical current is directed from a current source, such as a battery, through an electrically resistive medium, such as a filament wire, to the ammunition cartridge in the firing chamber to initiate the cartridge charge. 
     In an optical ignition system embodiment, the energy from an optical source, for example a laser, is directed into the firing chamber to trigger initiation of the ammunition cartridge. 
     The control system provides electronic control and facilitates remote operation of the multi-shot disrupter. The control system embodiment illustrated in  FIG. 6  includes multiple feedback sensors  240  and  270 , a user interface  295 , a command interpreter  290 , a command sequencer  280 , and a command execution system  200 . 
     The user interface  295  communicates the high-level machine state of the multi-shot disrupter to the user and allows human-readable user control. Feedback sensors  240  and  270  measure the machine states  231  and  261  of controlled devices  230  and  260  of the multi-shot disrupter and provide feedback sensor outputs  241  and  271 . 
     The user interface  295  renders machine state information originating from feedback sensor outputs.  291  into a human-readable form indicating the current machine state. The user interface  295  also provides human-readable command options associated with available machine states and allows the user to select a desired machine state from among available options. The user interface  295  outputs selected human-readable commands  296  to the command interpreter  290 . In some embodiments, the user interface  295  may communicate wirelessly or through a remote wired connection with other control system components, allowing remote operation of the multi-shot disrupter by the user. 
     The command interpreter  290  translates selected human-readable commands  296  from the user interface into a set of machine instructions  292 . The selected user-level commands are translated into the permissible machine-level instructions required to carry out the selected commands. For example, if a user selects a command “Load Cartridge A” the command interpreter  290  may perform several steps of command processing to determine the machine-level meaning of the command and the validity or permissibility of the command. Interpreted machine instructions  292  are output by the command interpreter  290  to the command sequencer  280 . The command interpreter  290  also receives processed feedback sensor outputs  282  from the command sequencer  280  and interprets, translates, and outputs resulting machine state information to the user interface  295 . 
     The command sequencer  280  is a processing block which, given the current state of the machine and the desired state of the machine, issues sequenced machine instructions  281  to the command execution system  200  according to control rules and information originating from feedback sensors  240  and  270 . Feedback sensor outputs  241  and  271  are received by subsystem controllers  220  and  250 . Information originating from the feedback sensors is processed by execution processor  210 , and passed through signal  211 , providing the command sequencer  280  with current machine-state information. The command sequencer  280  uses control rules to produce sequential machine-level commands transitioning from the current to the desired machine state. For example, if the machine state is 0001, and the final user-desired machine state is 0003, the command sequencer may issue sequential commands 0001-0002-0003 owing to a rule which precludes a direct machine transition from state 0001 to state 0003 due to a mechanical interference or other unallowable state that would occur if a direct transition from state 0001 to 0003 were attempted. Sequenced machine instructions  281  are issued from the command sequencer  280  to the command execution system  200 . 
     The command execution system  200  provides control of multi-shot disrupter devices using a command execution processor  210  and subsystem controllers  220  and  250 . The command execution processor  210  receives sequenced machine instructions  281  and provides individual control signals  212  and  213  to subsystem controllers  220  and  250  to control devices  230  and  260  of multi-shot disrupter such as actuator motors, pump motors, designator lasers, range measurement systems, cameras, and other similar devices. Although only two such subsystem control diagrams are illustrated in  FIG. 6 , it is understood that additional subsystem control blocks are necessary to control additional subsystems. Subsystem controllers  220  and  250  are comprised of analog and digital processing elements sufficient to provide control signals  222  and  252  to directly control associated devices  230  and  260 . Subsystem controllers  220  and  250  receive raw signals from feedback sensors  241  and  271  measuring the machine state of controlled devices  230  and  271  at a relatively high data rate. Subsystem controllers  220  and  250  adjust the direct control signals  222  and  252  sent to the controlled devices  230  and  250  toward a defined target value based on the feedback sensor data. Subsystem controllers  220  and  250  periodically send processed feedback sensor output  221  and  251  to the command execution processor  210 . The command execution processor  210  determines if the current command is executed sufficiently to allow the next sequential command according to defined rules. 
     Feedback sensors  240  and  270  measure the machine state of a controlled device  230  and  260 . A feedback sensor is designed to transduce a signal corresponding to a measured physical quantity into a processed feedback sensor output signal which serves as an input to a control system. For example, a Hall-effect quadrature encoder may be used to produce an electrical signal to indicate the rotational position and direction of a motor. This feedback sensor output signal, fed back to a controller, can be used to actively control the position and speed of the motor rotor. If the motor is the driver of a further mechanical system, one or more additional feedback sensors can be placed on intermediate or final stages of the mechanism, such that effects due to mechanical imprecision, mechanical flexing, or mechanical hysteresis can be accounted for to produce a sufficiently accurate and precise mechanical motion profile at the output stage. Other types of feedback sensors may be used such as optical encoders, transmission optical sensors, reflective optical sensors, inductive sensors, capacitive sensors, mechanical contact sensors, and mechanical limit switches. Feedback sensors  240  and  270 , illustrated in  FIG. 6 , provide outputs  241  and  271  in low-level raw signal form to subsystem controllers  220  and  250 . The feedback sensor outputs are further processed and used by other control system components to provide control and human-readable machine state information for the multi-shot disrupter. 
     Some embodiments incorporate an extractor into the multi-shot disrupter design. The extractor of the multi-shot disrupter removes ammunition cartridges and other objects from the firing chamber. The extractor embodied in  FIG. 2  operates to magnetically remove fired or unfired ammunition cartridges from the firing chamber  25 . In the  FIG. 2  embodiment, a permanent magnet attached to the multi-function end effector  61  of the feeder  60  is the engagement mechanism. The magnet engages the ammunition cartridge through movement of the feeder  60 . The ammunition cartridge is withdrawn into an open storage cavity in the rotary magazine  55  by operation of the threaded mechanism of the linear actuator  62  as directed by the control system. The ammunition cartridge is released from engagement through the motion of the rotary magazine substantially perpendicular to the barrel bore axis. 
     Other extractor embodiments engage the chambered ammunition cartridge through alternate means. Alternative embodiments to the permanent magnet embodiment of an engagement mechanism, including an electromagnet embodiment, a mechanical hook embodiment, a piercing barb embodiment, a drill-tap embodiment, an adhesive contact embodiment, and a compliant prehensile ring embodiment, are described below and are represented in  FIG. 2  by the box labeled  610 . In an electromagnet embodiment, the engagement mechanism of the extractor is a magnetic field induced by flow of electrical current which operates to magnetically remove fired or unfired ammunition cartridges from the firing chamber. An electromagnet attached to an electrical current source and in communication with the feeder engages the ammunition cartridge to withdraw the ammunition cartridge from the firing chamber. 
     In a mechanical hook engagement mechanism embodiment, a hook adapted to catch the rim or extraction groove of an ammunition cartridge operates in communication with the feeder to remove the ammunition cartridge from the firing chamber. 
     In a piercing barb engagement mechanism embodiment, a barb operates in communication with the feeder to pierce the body of the ammunition cartridge to allow the feeder to withdraw the ammunition cartridge from the firing chamber. 
     In a drill-tap engagement mechanism embodiment, a drilling device operates in communication with the feeder to pierce the body of the ammunition cartridge and thread a screw into the pierced hole in the cartridge head, allowing the feeder to withdraw the ammunition cartridge from the firing chamber. 
     In an adhesive contact engagement mechanism embodiment, an adhesive in communication with the feeder adheres to the ammunition cartridge and allows the ammunition cartridge to be withdrawn from the firing chamber. 
     In a compliant prehensile ring engagement mechanism embodiment, a compliant prehensile ring utilizing plastic deformation, such as annular snap fit or cantilever snap fit, is adapted to catch the rim or extraction groove of an ammunition cartridge. The compliant prehensile ring operates in communication with the feeder to engage and withdraw an ammunition cartridge from the firing chamber. 
     In a pressurized gas extraction mechanism embodiment, a pulse or stream of pressurized gas supplied from a pressure tank, combustion event, or other suitable source is introduced into the bore or chamber while the breech is in the unlocked condition. The pressurized gas applies rearward force to the cartridge head, freeing the ammunition cartridge from the firing chamber. 
     Lubricant can be applied to the surface of ammunition cartridges prior to firing. Lubrication reduces the adherence of the cartridge to the chamber surface during firing and facilitates subsequent ammunition cartridge extraction from the firing chamber. 
     Surface treatments can also be applied to the surface of ammunition or ammunition components prior to firing. Surface treatments include sandblasting, etching, peening, or other techniques which modify the surface texture and local hardness properties. These surface treatments modify the interaction with the ammunition cartridge and chamber surface during firing events, and also modify the performance of lubricants applied to the surface. 
     A number of embodiments incorporate a fluid filling system to adapt the multi-shot disrupter to discharge fluid projectiles. The fluid filling system embodiment detailed in  FIGS. 7A and 7B  includes a first seal plug  81  adapted to create a substantially fluid-tight fit while seated inside the bore of the barrel. The first seal plug  81  slides under moderate pressure along the length of the barrel bore while maintaining the fluid-tight fit against the bore wall. A second seal plug  82  creates a substantially fluid-tight closure of the rearward end of the barrel bore to prevent unpressurized fluid leakage, but is adapted to allow pressure-driven fluid flow into the barrel bore selectively through a liquid partitioning mechanism. 
     Many liquid partitioning mechanism embodiments can be used including: a resiliently biased slit, a nozzle plate, a valve, and a septum. In the first embodiment, a slit resiliently biased to the closed position, but which opens to allow fluid flow under pressure, is incorporated into the second seal plug. Alternatively, a nozzle plate incorporated into the second seal plug and containing a plurality of through-holes could be used. The nozzle plate holes are sized to provide fluid containment of the rearward end of the barrel bore as a result of hydraulic forces exerted through the column of fluid and the friction of the first seal plug  81  in the bore, as well as the viscosity and surface tension of the filling fluid used, but allow fluid flow under pressure. In another liquid partitioning mechanism embodiment, a one-way valve incorporated into the second seal plug, such as a flap opening toward the forward muzzle end of the barrel, allows fluid flow under pressure into the barrel bore, but closes to prevent fluid backflow. In a septum liquid partitioning mechanism embodiment, a resilient membrane in the second seal plug is pierced to allow injection of fluid under pressure into the barrel bore. The membrane resiliently closes to create a substantially fluid-tight seal following withdrawal of an injector incorporated into the fluid tight filling conduit system. 
     In preferred embodiments, the first seal plug  81  is adapted to removably nest with the second seal plug  82  to facilitate compact storage in the magazine and seating in the barrel bore using the feeder, and to minimize the empty volume between the first and second seal plug to minimize air bubble entrapment during fluid filling operations. 
     In preferred embodiments, the second seal plug  82  is adapted to lodge against the tapered surface of the forcing cone  31  at the transition from the chamber to the bore, arresting its forward motion at the point of interference. During filling operations, fluid driven by a pump  84  flows from a fluid reservoir  83  through a fluid-tight filling conduit system and the second seal plug into the barrel bore. As fluid enters the barrel bore, the first seal plug  81  advances along the barrel bore to create a fluid pocket within the bore for use as a projectile, while the second seal plug  82  remains at the forcing cone  31 . 
     The fluid tight filling conduit system  85  embodied in  FIG. 7B  includes a filling tube accessory  86 , a length of flexible hose line  88 , and a fluid tight channel  87  incorporated into the feeder  60 . In this embodiment, the flexible hose line  88  couples to the rearward end  63  of the feeder  60  using an Ander-Lign compression fitting; however, other fluid tight tube couplings could be used. In this embodiment, a fluid tight channel  87  runs through the feeder  60  allowing pumped fluid to pass from the flexible hose line  88  coupled to the rearward end  63  through the linear actuator and the multi-function end effector of the feeder. A filling tube accessory  86 , which is hollow and removably couples to form a contact seal against the multi-function end effector  61  and the second seal plug  82 , allows the pumped fluid to pass from the fluid tight channel  87  through the liquid partitioning mechanism of the second seal plug  82  into the barrel bore. 
     In the preferred embodiment, the filling tube accessory retracts into a storage cavity of the magazine. During fluid filling operation of a breech loading embodiment, the filling tube accessory, driven by the feeder of the loading system, seats a nested seal plug pair against the firing cone in the firing chamber and then channels fluid through the firing chamber. 
     The fluid filling system allows breech loading of fluid projectiles by remote operation preferred in many disrupter operations. However, other fluid filling systems could be used to load fluid projectiles into the multi-shot disrupter. 
     A number of embodiments address disrupter recoil through recoil absorbing systems and recoil reduction systems. A recoil absorbing system is defined as a system which converts the kinetic energy of a moving disrupter into waste heat. A recoil reduction system is defined as a system which reduces the amount of kinetic energy generated by a particular projectile launch process. During the firing process, recoil acts upon the disrupter as momentum imparted in the opposite direction of projectile travel. Recoil reduction systems reduce the initial amount of kinetic energy input into the disrupter during the firing event, while recoil absorbing systems dissipate kinetic energy of the recoiling disrupter after it has been fired. 
     The recoil system embodiment of  FIG. 8A  incorporates recoil absorbing and recoil reduction systems. The recoil absorbing system includes a dissipator system, a return-to-battery system and a motion guide. The motion guide  110  constrains the motion of the recoiling disrupter to move in a substantially linear path. A dissipator system functions to absorb the recoil kinetic energy by converting this energy to heat. The return-to-battery system moves the disrupter into a forward firing position along the motion guide. 
     In the preferred embodiment detailed in  FIG. 8B , the motion guide  110  is adapted to constrain the recoiling mass of the multi-shot disrupter along a substantially linear path using a rail attached to a mobile or emplaced platform. The dissipator system is moveably mounted to translate along the rail of the motion guide  110  upon a recoil chassis  122 . The recoil chassis rigidly couples to the multi-shot disrupter and transfers the recoil force from the disrupter to a hydraulic absorber assembly  130 . The body of the hydraulic absorber assembly  130  attaches to the recoil chassis  122  using mount brackets  124 . 
     The recoil system includes a transfer mechanism which transforms the motion of the recoil stroke to match the stroke of the dissipator system. As the recoiling disrupter and recoil chassis slide rearward along the motion guide  110 , a roller cam follower  123  rolls along a ramp  121  rigidly coupled to the motion guide  110 . The roller cam follower  123  is mounted to one end of a bell crank lever  126 . The bell crank lever  126  mounts to the recoil chassis  122  upon a lever fulcrum pin  125  and converts the longer rearward recoil stroke into a shorter stroke acting upon the hydraulic absorber assembly  130 . The bell crank lever  126  contacts a hydraulic piston rod  131  using a roller tip couple  127  which converts the arcing motion of the lever into linear motion acting upon the piston. The roller tip reduces transfer of side-loading forces from the lever to the rod or piston. The hydraulic piston rod  131  drives a hydraulic shock absorber to dissipate the recoil energy as heat. While the preferred embodiment for the transfer mechanism uses a roller cam follower and bell crank lever, other suitable mechanisms include crank slider mechanisms, planar linkages, Scotch yokes, and combinations of these mechanisms. 
     The preferred embodiment uses a variable-orifice hydraulic dissipator in the dissipator system. The variable-orifice hydraulic dissipator is designed to maintain a substantially constant reaction force throughout the recoil stroke. The length of the motion guide and size of the hydraulic shock absorber can vary to accommodate a wide range of recoil kinetic energy and transferred force according to the recoiling mass allowance and the level of force that the platform can tolerate. A variety of suitable hydraulic shock absorbers are commercially available. Other dissipator systems could alternatively be used including dry friction dissipators, pneumatic dissipators, magnetorheological dissipators, and electromagnetic dissipators. 
     The return-to-battery system readies the multi-shot disrupter for firing. In the embodiment of  FIG. 8A , the return-to-battery system is a motorized system. An engagement motor engages a transit motor  141  attached to the recoil chassis  122  with the motion guide  110 . The transit motor  141  moves the recoil chassis  122  to a pre-fire forward position along the motion guide  110 . A compressor motor  143  attached to the hydraulic absorber assembly  130  compresses the hydraulic shock absorber to reduce the motor power requirements of the transit motor during a stowage operation, where it would otherwise be required to supply power sufficient to move the disrupter and compress the hydraulic shock absorber. In some embodiments, this compressor motor may be unnecessary, if adequate power is available from the transit motor or by using gravity to assist return. Other return-to-battery systems could alternatively be used including spring systems, pneumatic systems and hydraulic systems. A gravity-based configuration could also return the system to battery position and assist in stowage by orienting the motion guide upward or downward to allow gravity to act upon the recoil chassis. 
     The preferred recoil mitigation embodiment also implements a recoil reduction system using mass-efficient apportionment design. A disrupter system is necessarily limited in the total mass allowable, whether to remain easily portable or to remain within the limits of a robot platform or robot armature. This total allowable mass limit may be divided conceptually into a recoiling mass portion and a fixed mass portion. The mass-efficient apportionment system reduces the initial amount of kinetic energy input into the firing disrupter by apportioning a maximized fraction of the allowed total mass into the recoiling mass and a minimized fraction into the fixed portion. The recoiling mass undergoes direct acceleration during fire, while the fixed portion is not accelerated directly during fire. Due to the conservation of momentum, the product of the disrupter mass and disrupter velocity of free recoil will be equal to the projectile momentum, the product of the projectile mass and projectile velocity, including gaseous components from the propellant. The disrupter kinetic energy of free recoil will then be equal to one half times the disrupter mass times the velocity of free recoil squared. Because of the linear relationship between kinetic energy and mass, and the squared relationship between kinetic energy and velocity, it is observed that a reduction in recoil kinetic energy is achieved by increasing the recoiling mass, if the recoil momentum is held constant. 
     In the  FIG. 8A  embodiment, the motion guide  110  is attached to a platform and, therefore, represents a fixed portion of the total mass of the multi-shot disrupter system. The preferred mass-efficient apportionment embodiment minimizes the mass of the motion guide  110  by limiting the length to the anticipated recoil chassis travel required for a maximum disrupter load and by choice of strong light weight materials such as aluminum and fiber-filled composites, with limited use of heavier materials such as steel for surfaces which must be hard, such as the recoil chassis contact surfaces of the motion guide. 
     The dissipator system embodiment of  FIG. 8B  includes a ramp  121  attached to the motion guide  110  representing a fixed portion and other components mounted to the recoil chassis  122  representing the recoiling mass portion of the total mass. The preferred mass-efficient apportionment embodiment minimizes the mass of the ramp  121  by limiting the ramp length to the anticipated roller cam follower  123  travel required for a maximum disrupter load and by choice of light weight materials such as aluminum for the bulk of the ramp structure, with limited use of heavier materials such as steel for surfaces which must be hard, such as the ramp surface which contacts the roller cam follower. The mass of the ramp is also minimized by reducing the height of the ramp necessary to actuate the full stroke length of the hydraulic shock absorber. The height of the ramp is minimized by choosing a leverage ratio of the bell crank lever in order to allow a shorter ramp to actuate a longer stroke. Because the bell crank lever is accelerated along the recoil chassis, it is included as recoiling mass, which serves to reduce recoil kinetic energy. 
     The recoiling mass mounted to the recoil chassis  122  is maximized through system design. In the preferred embodiment, the hydraulic absorber assembly  130  is mounted to the recoil chassis  122  using the mount bracket and, therefore, is included in the recoiling mass. The multi-shot disrupter is mounted to the recoil chassis  122  so the mass of the barrel, firing chamber structure, breech plate, magazine, feeder and firing mechanism are included in the recoiling mass. The recoil chassis-mounted multi-shot disrupter embodiment allows implementation of disrupter design changes without affecting the overall recoil profile so long as the original multi-shot disrupter mass is maintained. 
     The return-to-battery system embodiment of  FIG. 8A  includes an engagement motor and a transit motor  141  directly attached to the recoil chassis  122  and a compressor motor  143  attached to the hydraulic absorber assembly  130  also mounted to the recoil chassis  122 . Therefore, the mass of the return-to-battery system is included in the recoiling mass  220 . 
     The mass-efficient apportionment system disclosed maximizes the recoiling mass and minimizes the fixed portion of the disclosed system. Other mass-efficient apportionment systems could be used to vary the fixed portion and recoiling mass of other multi-shot disrupter designs. 
     It is also possible to directly reduce recoil momentum by altering the net momentum of the firing process. Systems that alter net momentum could be used with the multi-shot disrupter disclosed, including muzzle brakes and counter-shot mass systems. In a muzzle brake recoil reduction system, the net momentum is reduced by redirecting of a portion of the propellant gas to work against the direction of recoil. In a counter-shot mass recoil reduction system, the net momentum imparted to the disrupter is reduced by simultaneously firing one or more additional counter shot projectiles in a direction opposing or nearly opposing the primary projectile direction. 
     Some embodiments incorporate a target designation system to facilitate aiming of the multi-shot disrupter. The target designation system includes optical sight adapted to provide a visible or invisible targeting beam parallel to a barrel bore axis of the multi-shot disrupter, and a provision for directly viewing the targeting beam by eye, or indirectly viewing the targeting beam with the aid of a camera, telescope, or other imaging device. During operation, the targeting beam projected by the sight forms a light to mark a target positioned at a distance from the multi-shot disrupter. A visible or invisible laser module can be used to generate a targeting beam. Use of a visible targeting beam allows aiming of the multi-shot disrupter from a remote platform by an operator located at a safe standoff distance from a target, and also permits nearby persons to directly view the beam by eye as it is projected on the target. Use of an invisible beam requires the use of an intermediate sensor which is sensitive to the invisible wavelength, such as a CCD or CMOS video camera or a night vision device. In this case, the beam is not visible to nearby persons without the use of a camera or similar device. 
     In the preferred embodiment of  FIG. 9 , the sight  300  is positioned to provide a targeting beam coaxial or nearly coaxial and parallel to a barrel bore axis. The sight  300  includes a laser beam source  301  connected to a battery power source. The sight  300  of  FIG. 9  is fitted in a housing adapted to seat in the firing chamber  25  during aiming operations and seat in the multi-shot disrupter magazine for storage. During aiming operations, the laser beam source  301  is oriented toward the forward end of the firing chamber  25  and provides a targeting beam which extends through the barrel bore exiting the forward muzzle end  15  of the barrel  10 . 
     The through-bore position of the preferred embodiment of the target designation system provides accurate alignment of the barrel bore axis with a target by casting a marking light upon the target when alignment is achieved. The marking light is visible either directly by the disrupter operator in visual line-of-sight with the target or indirectly such as by an operator viewing the target through a camera, monitoring of a control system sensor response, viewing of the target through a mirror, or by other indirect means. Optical target designation is especially suited to remote robotic platform-mounted multi-shot disrupter operation when an operator located at a safe stand-off distance cannot safely aim the disrupter by manual positioning. 
     In the preferred embodiment, the housing is fitted with a magnet  304  to allow retraction using the feeder into a storage cavity in the multi-shot disrupter magazine. Retraction functions can be integrated using the control system to facilitate remote aiming operations between disrupter shots. 
     Some embodiments incorporate a range measurement system to measure the distance between the multi-shot disrupter and a target using a rangefinder. Range measurement facilitates accurate aiming of projectiles with low ballistic coefficients which follow a parabolic or other non-linear defined trajectory, such as liquid projectiles commonly used in disruptor firing. Range measurement also facilitates effective shot planning, since the projectile energy may decrease abruptly with the distance from the forward muzzle end of the barrel. Shot effectiveness would, therefore, depend upon range in order to deliver the planned energy to the target. 
     Although the rangefinder can be mounted directly to the disrupter or to another structure with a repeatable geometric relationship to the disrupter, consideration of rangefinder sensitivity to mechanical shock should be given when selecting the mounting position. Laser rangefinders with delicate optical components requiring precise alignment may be particularly sensitive to mechanical shock. In order to protect the rangefinder from mechanical shock of disrupter firing, the rangefinder is preferably secured to a body not subject to the full mechanical shock of firing, such as the robot arm, the motion guide, or another structure not rigidly coupled to the multi-shot disrupter or recoil chassis. The range measurement system embodiment of  FIG. 10  includes a rangefinder  320  mounted to the motion guide  110  of a recoil system. Other suitable mounting positions could be selected based upon the shock tolerance of the rangefinder and the use of special shock absorbing mounting structures. In some embodiments, a programmable offset can be used to account for range variance based upon variable rangefinder mounting positions. 
     Several types of commercially available rangefinders can be adapted for use in the range measurement system including: ultrasonic rangefinders, optical triangulation rangefinders, optical time-of-flight rangefinders, and laser phase-shift rangefinders. These rangefinders operate over a variety of distances and accuracies accommodating various multi-shot disrupter firing scenarios. 
     A laser phase-shift rangefinder is preferred in embodiments requiring accurate multi-shot disrupter firing from short distances relative to the target, such as centimeter to decameter distances. The laser phase-shift range finder operates by transmitting a laser beam modulated at a plurality of relatively-prime frequencies to a target positioned at a distance from the multi-shot disrupter and measuring the phase shift of the reflection to determine distance, with ranging ambiguity resolved by the use of a plurality of frequencies. The relative accuracy and range of measurement of laser phase-shift rangefinders coincides with the useful range of standard disrupters. 
     An optical time-of-flight rangefinder transmits a pulsed laser beam to a target positioned at a distance from the multi-shot disrupter and measures the timing of the reflection to determine distance. Due to the speed of light and the relative timing precision of portable electronic circuitry, time-of-flight rangefinding is typically limited to resolutions of one meter or greater, which is sufficient for long range use typical of rifles and other small arms. Due to detector dynamic range considerations, a time-of-flight laser rangefinder is typically not useful for short ranges typical of disrupter use, due to detector saturation. 
     An optical triangulation rangefinder transmits a laser beam to a target positioned at a distance from the multi-shot disrupter and measures the angle of the reflection from a second vantage point to determine distance. 
     An ultrasonic rangefinder transmits a pulsed wave to a target positioned at a distance from the multi-shot disrupter and measures the timing of the reflected echo to determine distance. 
     In some embodiments, the range measurement system can be integrated using the control system to facilitate remote aiming operations between disrupter shots. Use of a range measurement system improves aiming accuracy of the multi-shot disrupter from a remote platform by an operator located at a safe standoff distance from a target. 
     The method of the present invention relates to discharging successive disrupter ammunition cartridges in an arbitrary order selected by the user. The method of firing comprises the steps of providing a multi-shot disrupter apparatus of the present invention with a barrel, a firing chamber, a breech plate, a magazine, a feeder, a firing mechanism, and a control mechanism; and discharging at least two ammunition cartridges in an arbitrary order selected by the user with the disrupter apparatus. The method further comprises lubricating the ammunition cartridges with molybdenum disulfide, tungsten disulfide, hexagonal boron nitride, graphite, mica, cadmium plating, wax, lanolin, oil, silicone grease, or polytetrafluoroethylene (PFTE) lubricants prior to discharge. Lubrication of the ammunition cartridges facilitates post-firing extraction. Waxes for lubrication include paraffin, carnuba, ceresin and beeswax, to name a few. Oils for lubrication include petroleum, animal and vegetable-based oils. 
     The method allows the operator to repeatedly engage one or more targets using appropriate loads and projectiles without return transport of the disrupter to the operator by robotic mount or manual reloading. The operator may select, chamber and fire any load or projectile type stored in the magazine without advanced firing sequence preparation, allowing subsequent load and projectile selection tailoring based upon initial firing results. The arbitrary order introduction capability precludes the need to anticipate the required order of fire at the time of magazine loading. Arbitrary introduction of multiple user-selected loads is particularly suited to improve prior art remotely controlled disrupter embodiments. 
     Having described the invention in detail with reference to the accompanying drawings in which examples of embodiments of the invention are shown, it is to be understood the forgoing embodiments are not intended to limit the form of the invention. It should also be noted that these embodiments are not mutually exclusive. Thus, components or features from one embodiment may be assumed to be present or used in another embodiment, where such inclusion is suitable.