Apparatus and electric primer output data testing method

Exemplary methods and apparatus for testing an electrically fired item, e.g., a primer-only cartridge or all-up round (AUR) cartridge, in a variety of modes are provided. For example, a test system may provide a method of testing a primer-only cartridge and an apparatus to execute such method. Various parameters associated with operation of the electrically fired item, such as a primer or initiator, may be varied and measured using an embodiment including programmable selection of a pulse duration for firing control signals, a voltage of the firing control signals, and a number of pulses associated with the firing control signals. An inline resistance of the path of the control signals may also be adjusted. Test data including temperature, pressure, voltage, and/or current associated with operation of the electrically fired item may be measured during tests and displayed on a display device.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to a system and method for testing electrically initiated items, and more particularly to a system and method for testing an electric primer and an all up round (AUR).

BACKGROUND AND SUMMARY

An all up round (AUR) includes an assembled round or bullet comprised of, for example, a housing (cartridge), a primer, a projectile, and a propellant. Current test systems for AURs include instrumentation that measures parameters associated with firing the AUR such as case mouth pressure, velocity of the projectile, and action time, which is the time from when energy is applied to the primer of the bullet to when the projectile leaves the gun barrel muzzle. Current test systems for AURs are also known to test the propellant in the AUR. Some rounds include electric primers which are activated by an externally provided electric charge, as opposed to a mechanical impact. The electric primer in turn ignites the primary propellant. Existing testing equipment for AURs is unable to test the electric primer functionality. Further, existing test equipment is unable to control an application of required voltages in varied durations to the electric primer of the AUR.

In primers used in ammunition for rapid fire cannon guns, including guns having multiple revolving barrels, a need exists to detect the causes of a long action time that exceeds a maximum action (dwell) time. The maximum action time varies depending on the gun and ammunition configuration. One example of a maximum action time is about 570 microseconds for a 20 mm gun, although other suitable maximum action times may be required. An action time lasting longer than the maximum action time may cause damage to the gun.

A method and apparatus is provided that allows control of an applied voltage, duration, and resistance to initiate an electric primer and monitor output characteristics of either the primer or the AUR. The apparatus and method control several key elements with high specificity, including, for example, the applied voltage magnitude, the length of time voltage is applied (microsecond pulse duration), the number of voltage pulses, and an in-line resistance applied to the bullet's primer.

The present disclosure includes an apparatus and method for functionally testing electrically initiated items, such as primers, for temperature and pressure data. According to an illustrative embodiment of the present disclosure, an exemplary testing method is capable of determining a primer's pressure and temperature, while applying voltage to a cartridge's primer and controlling factors including varying degrees of voltage, pulse duration, number of pulses, and in-line resistance. The temperature and pressure data provide an indication of the dynamics of the primer's reaction to a firing pulse.

According to a further illustrative embodiment of the present disclosure, an apparatus is capable of testing for pressure, velocity, and action time in relation to, for example, an AUR, and in addition, testing temperature and pressure in relation to primer-only function while also subjecting the AUR or primer to varying degrees of voltage, pulse duration, number of pulses, and in-line resistance. Various embodiments can have different attributes or elements/steps.

According to a further illustrative embodiment of the present disclosure, an apparatus has been created capable of controlling various testing methods of an AUR and primer-only cartridge function.

In an exemplary embodiment of the present disclosure, a system is provided including at least one processor, a first section including a testing apparatus adapted to hold and initiate an electrically initiated gas generator initiator, and a second section coupled to the testing apparatus and operable to generate and selectively control an electrical firing signal to the initiator based on a plurality of firing signal input parameters. The plurality of firing signal input parameters comprise a voltage of the electrical firing signal and at least one of a pulse duration of the electrical firing signal and a number of pulses of the electrical firing signal. The system includes a third section comprising an input/output section including a user interface, and the user interface includes a display adapted to display a graphical user interface. The system includes a fourth section comprising a test fixture and an electrical characteristic measurement section operable to measure a plurality of parameters including voltage and current associated with the electrical firing signal. The test fixture comprises a housing adapted to couple to the testing apparatus. The fourth section further includes at least one of a pressure sensor and a temperature sensor coupled to the test fixture. The test fixture includes at least one internal port for receiving the at least one of the pressure sensor and the temperature sensor, and the electrically initiated gas generator initiator is positioned in the housing of the test fixture. The system further includes a machine instruction storage section comprising a plurality of machine readable instructions that when executed by the at least one processor cause the at least one processor to: generate a test selection prompt requesting a user to select one of a first test and a second test and configure at least the second section based upon a user selection of the first test; obtain the plurality of firing signal input parameters and configure at least the second section for the first test based on the plurality of firing signal input parameters; and execute the first test by generating a first user control trigger prompt, initiating sending a first firing activation signal to the second section in response to a user selection of the first user control trigger prompt, collecting the plurality of parameters from the fourth section generated during the first test, and displaying a graphical interface section on the display comprising electrically initiated gas generator initiator data. The electrically initiated gas generator initiator data includes temperature and pressure generated during the first test.

In another exemplary embodiment of the present disclosure, a test system is provided including at least one processor and a first section comprising a holder adapted to hold an electrically activated gas generator initiator positioned within a gas generator charge housing. The initiator is activated by application of at least one firing control signal. The system includes a second section comprising a power supply, a function generator, and a switch operable to selectively generate the at least one firing control signal based on a plurality of firing signal input parameters. The system includes a third section comprising test instrumentation operable to measure at least one of a pressure output and a temperature output from the gas generator initiator and to measure at least one of current data and voltage data during a test. The system includes a fourth section including an input/output section operable to receive user inputs and to output a plurality of outputs. The system further includes a fifth section comprising a machine readable storage section adapted to store a plurality of machine readable instructions operable for controlling the test system. The plurality of machine readable instructions when executed by the at least one processor cause the at least one processor to: receive a plurality of user inputs including user selection of a type of test and the plurality of firing signal input parameters; perform an initial configuration of at least the second section based on the plurality of firing signal input parameters; execute the test by operating the second section to generate the at least one firing control signal so as to activate the initiator and by operating the third section to collect the at least one of the pressure output and the temperature output and the at least one of current data and voltage data during activation of the initiator; and provide graphical user interface data to the fourth section for displaying the at least one of the pressure output and the temperature output and the at least one of current data and voltage data generated during the test.

In yet another exemplary embodiment of the present disclosure, a method of testing includes providing a first section comprising a holder adapted to hold an electrically activated gas generator initiator positioned within a gas generator charge housing. The initiator is configured to activate by application of at least one firing control signal comprising an electrical signal. The method includes providing a second section comprising a power supply, a function generator, and a switch operable to selectively generate the at least one firing control signal based on a plurality of firing signal input parameters. The method includes providing a third section comprising a test instrumentation operable to measure at least one of a pressure output and a temperature output from the gas generator initiator and to measure at least one of current data and voltage data during a test. The method includes providing a fourth section including an input/output section operable to receive user inputs and output a plurality of outputs. The method includes receiving a plurality of user inputs including user selection of a type of test and the plurality of firing signal input parameters and performing an initial configuration of at least the second section based on the plurality of firing signal input parameters. The method includes executing the test by operating the second section to generate the at least one firing control signal so as to activate the initiator. The method includes operating the third section to collect the at least one of the pressure output and the temperature output and the at least one of current data and voltage data during activation of the initiator. The method further includes generating graphical user interface data for display on the fourth section comprising the at least one of the pressure output and the temperature output and the at least one of current data and voltage data generated during the test.

In still another exemplary embodiment of the present disclosure, a method of testing includes providing a control section comprising a programmable DC power supply, a function generator, and a switch operable to selectively generate a firing control signal. The method includes providing an oscilloscope operable to measure the firing control signal. The method includes selecting a voltage amplitude on the programmable DC power supply. The method includes inserting a cartridge into a cartridge port of a test vessel and coupling the test vessel with the cartridge to a firing breech, and the cartridge includes a primer. The method includes positioning at least one of a pressure transducer and a temperature sensor in the cartridge proximate the primer. The method includes selecting at least one input parameter for the firing control signal. The at least one input parameter includes at least one of a pulse duration and a number of pulses associated with the firing control signal. The method includes activating the primer by applying the firing control signal to the primer. The method further includes collecting and displaying on a display data based on output from the at least one of the pressure transducer and the temperature sensor.

Additional features and advantages of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring initially toFIG. 1, an exemplary schematic of a testing system10is depicted for a function test of an electrically initiated item, for example, a primer function test or an all up round (AUR) function test, according to some embodiments. Test system10is operative to provide instrument control, data handling, and file I/O functionality for a primer and AUR function test.

For the primer test, test system10includes a test fixture71that is configured to couple to a firing breech or holder apparatus83for testing the functionality of a primer, as described herein. Firing breech83includes a structure that contains a firing pin81for delivering the firing pulse to the primer. In the primer test, a cartridge77of a round including a primer80is inserted into test fixture71for testing, with the projectile and propellant removed from cartridge77. Test system10is also operative to conduct an AUR test, as described herein. In the AUR test, a projectile barrel is coupled to a firing breech, such as firing breech83, and test system10fires the AUR (the assembled cartridge, primer, projectile, and propellant) while monitoring parameters associated with the firing of the AUR. In the AUR test, test fixture71is not used and the AUR projectile associated with a cartridge (e.g., cartridge77) is fired through the projectile barrel during the test. The projectile barrel may include a replica of a gun barrel that is configured to attach to firing breech83. As such, whileFIG. 1illustrates a primer test configuration with test fixture71, the AUR test configuration uses the full length barrel (e.g., see cutaway portion54of full length barrel inFIG. 19) rather than the test fixture71with firing breech83.

An exemplary AUR52is illustrated inFIG. 19. Referring toFIG. 19, AUR52includes a cartridge or shell63, an electric primer64, a projectile53, and a propellant (not shown) contained in the cartridge63. In one embodiment, cartridge63and primer64have a same configuration as respective cartridge77and primer80ofFIG. 1used in the primer only test. When a firing pulse activates primer64, primer64causes the propellant to ignite to thereby fire the projectile53. A cutaway view of an exemplary barrel portion54is also illustrated inFIG. 19including a barrel opening55for receiving AUR52. Barrel portion54is cut off in length (at second end58) and in width for illustrative purposes but may have a length of several feet. In one embodiment, barrel portion54is a test barrel configured to couple to a firing breech (e.g., firing breech83ofFIG. 1) for performing an AUR test. A first end56of barrel portion54is configured to couple to the firing breech83(FIG. 1) such that firing pin81(FIG. 1) of breech83engages primer64.

Referring again toFIG. 1, test system10includes a user interface, illustratively a keyboard1and a monitor3, for receiving user inputs and communicating output data to a user. In one embodiment, computing device7provides a graphical user interface on monitor3for displaying test data, control inputs, and other suitable display data. Other suitable user interfaces may be provided, including a touchscreen and a mouse pointer device. Computing device7is coupled to the user interface and includes one or more processors. Test software12is stored in internal or external memory8of computing device7and is executed by the one or more processors to perform the testing functionality described herein. In the illustrated embodiment, test software12of computing device7includes an operating system and primer/AUR test software stored on an internal or external storage medium8. In one embodiment, test software12includes LabVIEW® software provided by National Instruments, although other suitable test software may be provided. Computing device7is operative to control function generator17, oscilloscope51, and data acquisition card9.

Computing device7includes an interface board5, illustratively a General Purpose Interface Board (GPIB)5, and a data acquisition board9each in communication with the executed test software12. In one embodiment, interface board5is an IEEE STD 488 interface card. Interface board5provides a communication interface between computing device7and various components of test system10, including a function generator17and an oscilloscope51, for example. An exemplary interface board5is a PCI-PCIB from National Instruments, and an exemplary data acquisition board9is PCI-6115 from National Instruments, although other suitable boards5,9may be provided. Data acquisition board9is connected to a pressure transducer67and a temperature sensor65via a connector block19. Pressure transducer67and temperature sensor65are configured to provide signals representative of pressure and temperature, respectively, of primer80during the primer function test, and data acquisition board9captures and routes the signals to appropriate memory of computing device7. An exemplary temperature sensor65is a self-eroding thermocouple whose output is amplified by an amplifier integrated circuit (e.g., amplifier39). Various communication cables, e.g., cables11,13,15,21,29,47,55,57, and63(e.g., low noise cable), etc. are used to couple various components of testing system10together.

Arbitrary waveform/signal generator17and multi-channel oscilloscope51are connected to computing device7via the GPIB interface card5. Arbitrary waveform/signal generator17is connected to a firing box or apparatus41via cable29. Although function generator17is illustrated as a standalone component inFIG. 1, in other embodiments function generator17may be incorporated in firing box41or computing device7. In the illustrated embodiment, firing box41(depicted by dashed lines) is operative to control the application of the firing pulse from signal generator17to firing breech83as well as amplify sensor output signals such as the temperature signal. In the illustrated embodiment, firing box41contains a safe/arm key switch33, a power switch35, and a high speed/high voltage switch37operable to rapidly output high voltage firing pulses based on the signal generated by signal generator17. In one embodiment, switch37is a 500 VDC, 3 Ampere (A) switch, although other suitably rated switches may be provided. In one embodiment, switch37is operative to provide high voltage firing pulses having a magnitude ranging between zero volts and 500 volts and a duration ranging between one and a 1000 microseconds. Other minimum/maximum voltage magnitudes and durations may be provided. A fire pulse output84,86from switch37is routed through conductors43coupled to firing box41via connectors91(FIG. 2) to electrical connectors85coupled to firing breech83.

Firing box41further includes an amplifier39operative to amplify a small voltage (or current) signal received from thermocouple65to a level that can be accurately measured by data acquisition board9. A circuit42, illustratively including resistors and a Zener diode, is operative to regulate power input to amplifier39and to switch37. A current viewing/current limiting resistor31of firing box41is operative to provide circuit protection by limiting current through box41and to provide current/voltage monitoring capability for oscilloscope51on a first channel of oscilloscope51, e.g., the current being delivered to the firing pulse. Oscilloscope51is further operative to monitor the firing pulse output voltage (84,86) delivered to primer80on a second channel.

Potentiometers89are configured to create in-line resistance between the pulse output and primer80that is variable by a user, as described herein. Programmable DC power supply23is connected to firing box41via connectors25to provide VDC power for the firing pulse. A battery27is also coupled to firing box41to supply VDC power to switch37and amplifier39of firing box41. An exemplary battery27is a 6 VDC lantern battery, although other suitable batteries may be provided. In one embodiment, oscilloscope51and DC power supply23are coupled to firing box41via banana jack connectors.

In the illustrated embodiment, high speed/high voltage switch37is controlled by waveform/signal generator17. In one embodiment, the output of waveform/signal generator17is also routed to and captured by data acquisition card9. Oscilloscope51monitors the firing voltage routed through conductors43. An exemplary oscilloscope51is a model DSO6014A oscilloscope provided by Agilent Technologies, Inc. Firing pulses routed from firing box41to firing breech83include a positive (+) firing pulse84and a negative (−) firing pulse86. In the illustrated embodiment, oscilloscope51is connected to the conductors43of (+) firing pulse84and (−) firing pulse86for monitoring on the first channel. Oscilloscope51is further operative to provide monitored waveform data to computing device7via cable11.

Test fixture71ofFIG. 1includes a test vessel or “test bomb”79, a sensor mount72, and a plurality of fasteners (e.g., screws)76for coupling sensor mount72to test vessel79. In the illustrated embodiment, firing breech83includes a threaded end87configured to receive a corresponding threaded end78of test vessel79. Firing breech83further includes a spring-loaded firing pin81that routes the firing pulse from firing box41to primer80. Firing pin81is illustratively centered in the opening formed in threaded end87for contacting primer80to deliver the firing pulse to primer80. In the illustrated embodiment, threaded end87of breech83is opposite an end of firing breech83containing the connectors85that receive the input firing pulses.

Sensor mount72of test fixture71includes a head portion74for receiving screws76and an elongated portion73. Thermocouple65and pressure transducer67are coupled at the distal end of elongated portion73opposite head portion74. Elongated portion73includes a pair of sensor ports69routed internally along a longitudinal axis of elongated portion73for routing electrical conductors to thermocouple65and pressure transducer67. When sensor mount72is fixed to test vessel79, elongated portion73is sized to position sensors65,67adjacent primer80inside of cartridge77for measuring the temperature and pressure of primer80during a firing event. In one embodiment, elongated portion73includes one or more standoff screws at its distal end for coupling to test vessel79.

To test primer80, cartridge77, containing primer80but with the projectile and propellant removed, is inserted into a cartridge port (opening)75of test vessel79. Test vessel79is then affixed to firing breech83at threaded end78. Sensor mount72is fastened to test vessel79to position thermocouple65and pressure transducer67adjacent primer80.

Pressure transducer67is connected to a charge amplifier61which is connected to connector block19via cable21, and connector block19is connected to data acquisition board9via cable15. Charge amplifier61serves to amplify the signal output from pressure transducer67to a level readable by data acquisition board9. Thermocouple65is connected to amplifier39, i.e., to allow a small voltage received from the thermocouple material to be amplified to a level that may be accurately measured by data acquisition board9of computing device7. In one embodiment, amplifier39includes an integrated circuit. In the illustrated embodiment, amplifier39is positioned inside firing box41.

In the illustrated embodiment, computing device7executes testing software12to control and interact with firing box41and test fixture71in such a way as to collect data on primer pressure, primer temperature, voltage and current applied to primer80(monitored via oscilloscope51), and input voltage/current to firing box41, while controlling the applied voltage magnitude, pulse duration, number of pulses, and in-line resistance applied to specified levels or amounts.

Referring toFIG. 2, an exemplary embodiment of an outside of a firing box (e.g., firing box41ofFIG. 1) is illustrated. In this embodiment, the firing box includes input and output features such as a firing voltage output91, a thermocouple signal input93, a battery power input95, a thermocouple signal output105, a function generator input103, a direct current (DC) power supply input101, a firing current connector99, and an inline resistance adjustment97. These features interact with other sections of the exemplary testing system, including testing software, operable for controlling testing variables, energy, and data, etc.

In particular, firing voltage output91includes a pair of electrical connectors for coupling electrical cables (e.g., conductors43ofFIG. 1) that route the firing pulses to firing breech83ofFIG. 1. Thermocouple signal input93includes an electrical connector that receives the thermocouple signal from connector45(FIG. 1), and thermocouple signal output105includes a connector that routes the thermocouple signal amplified by amplifier39(FIG. 1) to a connected cable57(FIG. 1) for receipt by data acquisition board9of computing device7. Battery power input95includes positive and negative terminal connectors for connection of battery power, such as power from battery27ofFIG. 1, for powering components of the firing box. DC power supply input101illustrates exemplary connectors25ofFIG. 1for routing VDC power from DC power supply23(FIG. 1) for the firing pulse output. Function generator input103includes an electrical connector for receiving the signal generated by waveform/signal generator17(FIG. 1) and routing the signal to switch37(FIG. 1) of the firing box. Inline resistance adjustment inputs97illustratively include a pair of rotatable knobs or handles. A user's adjustment of the rotational position of inputs97causes adjustment of the pair of potentiometers89ofFIG. 1to thereby adjust the inline resistance. In one embodiment, the inline resistance simulates a total inline resistance between the output of a firing pulse generator in a gun and the primer of the bullet. The inline resistance is varied to control the characteristics of the voltage delivered to primer80, as described herein. Firing current connector99includes an electrical connector to allow current flow to a fired primer80to be monitored by oscilloscope51, such as at resistor31ofFIG. 1.

Referring still toFIG. 2, the exemplary firing box further includes an on and off switch input109and a safe and arm key input111. On/off switch input109illustratively includes a toggle switch for controlling the on/off power switch35of firing box41ofFIG. 1. Safe and arm key input111includes a key assembly for controlling the position of the safe/arm key switch33ofFIG. 1. As such, a key is required to enable power to the firing box.

Referring toFIG. 3, an exemplary test fixture71ofFIG. 1is illustrated including T-shaped sensor mount72and test vessel79. Head portion74of sensor mount72and test vessel79each include spaced apertures113,115for receiving fasteners76(FIG. 1). Pressure transducer67and thermocouple65ofFIG. 1are positioned in ports69at distal end117of elongated portion73. With cartridge77positioned in opening75of test vessel79, elongated portion73is positioned in opening119of cartridge77such that pressure transducer67and thermocouple65are positioned inside cartridge77near or abutting primer80(FIG. 1) positioned at end120of cartridge77. In one embodiment, cartridge77is a 20 millimeter (mm) cartridge, although other sizes of cartridge77may be provided. In one embodiment, test vessel79is a pressure vessel in which cartridge shell77is inserted such that primer80faces outwardly from threaded end78of test vessel79and the open end of cartridge77is aligned with a narrow open end of test vessel79for receiving elongated portion73. Once cartridge77is inserted in test vessel79, test vessel79is connected to firing breech83(FIG. 1) by screwing together threaded portions87,78of firing breech83and test vessel79, respectively.

Referring toFIGS. 4A and 4B, an exemplary primer80of cartridge77ofFIG. 1is illustrated. Primer80includes a non-conductive cup or outer casing121that is substantially cylindrical in shape with a U-shaped cross-section. A metal conductor or button123is located in cup121, and an insulator122(e.g., rubber) is positioned between cup121and metal conductor123. Cup121is open at a first end124of primer80to allow the firing pin (e.g., firing pin81ofFIG. 1) to engage metal conductor123. A primer fill or mix125is located in cup121between metal conductor123and a disc127, which spans the interior width (diameter) of cup121. A cup support member129is positioned in cup121over disc127at a second end126of primer80. In the exemplary embodiment, pressure transducer67and thermocouple65(FIG. 1) are positioned adjacent disc127through opening128in support cup129when test fixture71and cartridge77(FIG. 1) are assembled for measuring the pressure and temperature of primer80. In one exemplary embodiment, primer80has a resistance between 1,000 ohms and 1,000,000 ohms.

In one example, primer fill125is made of acetylene black, barium nitrate, calcium silicide, technical acacia (gum arabic), lead styphnate, and 2, 4, 6 trinitroresorcinol. In one example, cup121, button123, and support cup129are all made of conductive material and are insulated by insulator122. In one example, insulator122is polyvinyl chloride/vinyl acetate copolymer modified. In one example, disc127is a paper material coated with shellac. Other suitable materials for primer80may be provided. In one embodiment, the firing voltage that reaches button123, which is insulated from cup121and support cup129by insulator122, is targeted to be sufficient to conduct through primer mix125and complete a circuit to cup121, which functions primer mix125from the heat build-up.

Referring toFIG. 5, a graphical user interface (GUI)140of test system10ofFIG. 1is illustrated according to some embodiments. GUI140is provided by computing device7for display on monitor3ofFIG. 1. A user provides user input to GUI140via any suitable user input device coupled to computing device7, such as keyboard1(FIG. 1), a touchscreen, pointing device (e.g., mouse), etc.

GUI140includes selectable data, such as selectable inputs, fields, modules, tabs, drop-down menus, boxes, and other suitable selectable data, that are linked to and provide input to the components of system10ofFIG. 1. In one embodiment, the selectable data of GUI140is rendered in a manner that allows it to be individually selectable. For example, the selectable data is selected by a user with a mouse pointer, by touching a touchscreen of the user interface, by pressing keys of a keyboard (e.g., keyboard1ofFIG. 1), or by any other suitable selection mechanism. GUI140further displays monitored data, including temperature, pressure, voltage, and current data, provided from components of system10that is displayed with the selectable data.

In the illustrated embodiment, GUI140includes an exemplary software test system front panel for a 20 mm bullet initiation system. Other caliber bullets or rounds may be tested, including AUR and primer only tests of varying calibers. GUI140displays a plurality of test data indicators. For example, a top left quadrant of GUI140includes a graph130of current applied to a primer versus time during a primer only or AUR test. A top right quadrant of GUI140includes a graph132of an output voltage applied to a primer versus time during the primer only or AUR test. A bottom portion of GUI140includes a graph131of temperature and pressure data versus time monitored during a primer only or AUR test. In one embodiment, temperature and pressure data displayed on graph131is displayed in raw form as well as after passing through a lowpass filter (e.g., 1000 Hz Lowpass Butterworth Filter) or other suitable filter. A menu bar134is provided which provides selectable user inputs such as start, pause, and stop functionality for testing operations.

Referring toFIG. 6, an exemplary start-up state menu133of GUI140is illustrated. Testing system10is activated by a user via a control menu run button of menu134(FIG. 5) which generates the active window133that prompts a user to select a type of test to be performed: for example, an AUR test or primer only test, or a user may quit software testing system.

Computing device7ofFIG. 1executes a software program, such as test software12ofFIG. 1, to run the primer and AUR tests and to generate the GUI140ofFIGS. 5 and 6.FIGS. 7-13illustrate exemplary code modules of the testing software program executed by computing device7. In the illustrated embodiment, the software program ofFIGS. 7-13is a LabView® program that uses a state machine type architecture, although other suitable programming languages may be used. Each program module ofFIGS. 7-13illustrates a different state of the software routine.

Referring toFIG. 7, an exemplary LabView® hierarchical block diagram of a start-up state144is depicted in an exemplary system-design platform and development environment for a visual programming language. Computing device7executes a case structure135(e.g., hierarchical block structures, lines, and shift register) that prompts a user for “Type of Test” (see prompt window133ofFIG. 6), initiates a function generator control module137for initializing and controlling function generator17ofFIG. 1, and at modules139either stores for later output or sends test data indicators (e.g., primer temperature and pressure data, current, output voltage) to the GUI140(FIGS. 5 and 6) once the user selects and runs a desired type of test inFIG. 6. Interface card5ofFIG. 1is also designated at block136to interface the test software12(FIG. 1) with the card5. An error handling module138is also input into the model. A sub-visual instrument (VI) element may be included in the block diagram which initializes/enables the function generator17ofFIG. 1. The block diagrams ofFIGS. 7-13include other features such as a wait function142which in this example causes the case register to wait a predetermined time, illustratively 125 milliseconds, between state changes in order to assist a user in comprehending and absorbing test data presented in the user interface graphs130,131,132ofFIGS. 5 and 6. In other words, wait function142permits test data to be displayed for a threshold amount of time before a user prompt is generated.

Referring toFIG. 8, an exemplary LabView® hierarchical block diagram for an AUR test configuration state146is depicted in an exemplary system-design platform and development environment for a visual programming language. AUR state146is operative to configure components of test system10to perform an AUR test. Computing device7executes a case structure that at block141prompts a user via GUI140(FIG. 5) for desired firing pulse parameters (e.g., desired voltage and voltage signal duration of firing pulse; also number of pulses in some embodiments). Upon receiving the desired pulse information via user input, computing device7confirms at block143that the user input pulse information is within an allowed range (e.g., a voltage magnitude range of 0 to 400 VDC and a voltage duration range of 1 to 1000 microseconds). At module145, computing device7initializes and configures oscilloscope51ofFIG. 1to collect data, and in particular to collect waveform data of the voltage and current to be applied to the AUR.

At module147, computing device7configures function generator17and firing box41ofFIG. 1to generate a voltage signal (firing pulse) at the desired magnitude and over the user specified duration. In one embodiment, the desired voltage duration is achieved by instructing switch37of firing box41(FIG. 1) to close for the specified duration. Computing device7may control switch37directly, or function generator17may control switch37based on instruction from computing device7. In the illustrated embodiment, the actual firing pulse is not generated in state146, but function generator17, firing box41, and oscilloscope51ofFIG. 1are prepared for the test. In one embodiment, modules139ofFIG. 8are configured to output the test data indicators immediately or to store the data and generate such output test data indicators in a subsequent state based on stored data.

Referring toFIG. 9, an exemplary LabView® hierarchical block diagram for configuring and executing a trigger state148fromFIG. 8for triggering the AUR test is depicted in an exemplary system-design platform and development environment for a visual programming language. Computing device7at module149prompts the user for a trigger command via a prompt window of GUI140(FIG. 5). Upon receiving the trigger command, computing device7at module151sends the trigger command to function generator17ofFIG. 1which sends a voltage signal to firing box41ofFIG. 1. At module153, computing device7configures oscilloscope51(e.g., sample rate, record time, voltage range, vertical resolution, volts per division, etc.) and retrieves data from oscilloscope. The retrieved data is recorded via data acquisition device control module155(e.g., configures data acquisition board9ofFIG. 1to record the test data). In the AUR test ofFIGS. 8 and 9, current applied over time to the AUR is measured and recorded as well as voltage applied to the AUR (e.g., via oscilloscope51). In the AUR test ofFIGS. 8 and 9, pressure and temperature data may or may not be measured. Additional data measured and recorded during the AUR test includes velocity of the projectile through the gun barrel, case mouth pressure, and action time. The inline resistance may also be adjusted during the AUR test with potentiometers89(FIG. 1).

Referring toFIG. 10, an exemplary LabView® hierarchical block diagram for configuration state150for a primer test is depicted in an exemplary system-design platform and development environment for a visual programming language. Computing device7receives the desired pulse parameters at module157from the user based on prompts via GUI140(e.g., selection of AUR test, primer only test, or quit; prompts for voltage magnitude, voltage signal duration, and number of pulses). At module159, computing device7confirms the user input pulse information (e.g., voltage/voltage signal duration/number of pulses) is within the allowed ranges, as described above with respect toFIG. 8. At module161, computing device7configures oscilloscope51ofFIG. 1to record data (e.g., sample rate, record time, voltage range, vertical resolution, volts per division, etc.). At module163, computing device7configures function generator17ofFIG. 1for the primer test (e.g., sets a voltage and a voltage signal duration from the function generator). In one embodiment, the desired voltage duration specified by the user is achieved by instructing switch37of firing box41(FIG. 1) to close for the specified duration, as described above. In the illustrated embodiment, the actual firing pulse is not generated in primer test state150, but function generator17and firing box41ofFIG. 1are prepared for generating the firing pulse at module147. Data may or may not be recorded in the primer state150configuration process.

Referring toFIG. 11, an exemplary LabView® hierarchical block diagram of executing the trigger primer state152fromFIG. 10is depicted in an exemplary system-design platform and development environment for a visual programming language. Computing device7at module165prompts the user for a trigger command via a prompt window of GUI140(FIG. 5). Upon receiving the trigger command, computing device7at module167sends the trigger command to function generator17ofFIG. 1which sends a voltage signal to firing box41ofFIG. 1, and firing box41outputs the firing pulse to primer80based on the specified user input parameters. At block169, computing device7collects current and voltage data (e.g., from oscilloscope51) applied to primer80under test, applies at block171a transfer function to raw temperature data collected from temperature sensor65ofFIG. 1, and collects at block173temperature and pressure data obtained from respective temperature sensor65and pressure transducer67ofFIG. 1. The system also generates test data indicators (e.g., primer data (pressure and temperature), current applied to primer, output voltage applied to primer) for display on GUI140based on the captured data.

While the in-line resistance is described herein as being manually adjusted via input devices coupled to the firing box41, in another embodiment computing device7is configured to prompt a user for a desired in-line resistance and to automatically adjust one or more potentiometers or variable resistors to achieve the desired in-line resistance. For example, in some embodiments the software modules described herein further include a resistance adjustment functionality to adjust the in-line resistance and thereby the input voltage/current firing pulse signals received by the electrically initiated gas generator (e.g., primer, cartridge, AUR, etc.).

Referring toFIG. 12, an exemplary block diagram of a save data state154is depicted in an exemplary system-design platform and development environment for a visual programming language. In this example, computing device7at block175saves data generated in other states, e.g., states ofFIGS. 7 through 11, to a data file in memory8ofFIG. 1. In one embodiment, the data is stored in an Excel® format.

Referring toFIG. 13, an exemplary block diagram of a quit state156is depicted in an exemplary system-design platform and development environment for a visual programming language. Execution of the software testing program can be terminated and the program closed via the quit state156. For example, user selection of the Quit input in the prompt133ofFIG. 6results in termination of the testing program.

Referring toFIG. 14, a flow diagram176of an exemplary method of testing system10is illustrated. The function blocks ofFIGS. 14-16are performed by computing device7ofFIG. 1executing test software12. In one example, software processing sequences stored on a machine readable media (e.g., memory8ofFIG. 1) controls two separate tests that run independent of one another. A first test is for testing the AUR with the propellant and projectile installed in the cartridge. A second test is for primers only and uses cartridges with the projectile and propellant removed. Such a software system allows a user to automate a firing process and to monitor data captured during the firing process. Reference is made toFIG. 1throughout the following description ofFIGS. 14-16.

At block177ofFIG. 14, computing device7initiates the test system program12based on user input received via a user interface (e.g., keyboard1, monitor3) of test system10. When test system software is initiated, computing device7initializes function generator17at block179and launches a start-up state, such as start-up state144ofFIG. 7. From the start-up state, computing device7prompts a user at block181to select which test to run (e.g., prompt window133ofFIG. 6), illustratively either the AUR test or the primer test. If the AUR test is selected at block183, computing device7proceeds toFIG. 15to run the applicable AUR test and collect data. If the primer test is selected at block183, computing device7proceeds toFIG. 16to run the applicable primer only test and collect data.

Referring to the AUR test ofFIG. 15, computing device7prompts the user at block185to enter pulse parameters including, for example, the desired pulse magnitude, desired pulse duration, and desired number of pulses to be generated. Computing device7confirms at block187that the entered parameters are within the respective allowable ranges. At block189, computing device7sends the selections from the user to function generator17and configures oscilloscope51for data acquisition. At block191, computing device7confirms that the user is ready to test by prompting (via GUI140ofFIG. 5) the user for the trigger command. At block193, computing device7receives the user instruction trigger the firing pulse, and in response computing device7sends a trigger command to function generator17at block195, and function generator17outputs the trigger signal to switch37of firing box41for controlled output to the AUR. Once the firing pulse is sent to the AUR by firing box41, the projectile in the AUR is fired down range. During the firing, computing device7retrieves data (e.g., voltage and current input to firing box41and output to the AUR) from oscilloscope51and records the voltage and/or current via data acquisition board9at block197. At block199, computing device7returns to block221ofFIG. 14to display the captured data on GUI140(FIG. 5) and to prepare to fire the next AUR or primer.

Referring toFIG. 16, the primer only test is selected at block183ofFIG. 14. Blocks203,205,207,209,211, and213of the primer test ofFIG. 16are the same as blocks185,187,189,191,193, and195of the AUR test ofFIG. 15. At block215ofFIG. 16, once the firing pulse(s) is output to primer80in cartridge77(FIG. 1), computing device7retrieves data from the oscilloscope, records voltage via data acquisition board9, collects pressure and temperature data via data acquisition board9, and causes the sub-visual instrument element of the software routine to apply a transfer function to convert the raw temperature data from a voltage to a temperature. Computing device7then proceeds to save the data including, for example, the primer temperature and pressure data and voltage and current at block217. Computing device7returns to block221ofFIG. 14to display the captured data on GUI140(FIG. 5) and to prepare to fire the next AUR or primer.

Referring toFIG. 17, a flow diagram22of an exemplary method for testing an electric primer is illustrated. Reference is made to the test system10ofFIG. 1throughout the description ofFIG. 17. At block223, a user powers on the firing box41, computing device7, function generator17, and oscilloscope51and then initiates the software test system (software12) via the user interface at block225. The user sets a voltage amplitude on programmable DC power supply23at block227and selects an in-line resistance via inputs97(FIG. 2) at block229. At block231, computing device7executing test software12initiates function generator17in response to the user initiating the software at block225. The user inserts primer cartridge77into the cartridge port75of test vessel79at block233and affixes test vessel79to firing breech83at block235. At block237, the user inserts the sensor mount72with sensors65,67into test vessel79and cartridge77and affixes the sensor mount72to the test vessel79with fasteners76. In another embodiment, at block239, the user inserts pressure transducer67and thermocouple65into the sensor ports69after the test fixture71is assembled.

At block241, the user selects the “Primer” test from software test system start up state menu133(FIG. 6), and at block243the user enters pulse parameters when prompted by the test system software, including the desired pulse duration and magnitude and the number of pulses to be sent to primer80, for example. The user receives confirmation from the software test system (e.g., via GUI140) that the desired pulse parameters are within the acceptable ranges at block245and confirms readiness when prompted by the software test system at block247. The user may also adjust the inline resistance via inputs97ofFIG. 2. At block249, the user selects the trigger command to initiate the firing pulse and begin the test, and test system10executes the test and collects appropriate data. At block251, the user returns to the GUI140to view data collected from the test, returns to start up state menu to select a new test, and/or exits the software test system program.

Referring toFIG. 18, an exemplary method for testing an AUR output is illustrated. Blocks253,255,257,259, and261of the AUR test ofFIG. 18are the same as blocks223,225,227,229,231of the primer test ofFIG. 17. At block263, the user inserts the AUR (e.g., AUR52ofFIG. 19) into the firing apparatus (e.g., gun barrel54ofFIG. 19) and affixes the firing apparatus to the firing breech83. At block265, the user selects “All Up Round” test from software test system start up state menu133(FIG. 6), and at block267the user enters pulse parameters when prompted by the test system software, including the desired pulse duration and magnitude and the number of pulses to be sent to the AUR, for example. The user receives confirmation from the software test system (e.g., via GUI140) that the desired pulse parameters are within the acceptable ranges at block269and confirms readiness when prompted by the software test system at block271. The user may also adjust the inline resistance via inputs97ofFIG. 2. At block273, the user selects the trigger command to initiate the firing pulse and begin the AUR test. At block275, the user returns to the GUI140to view data collected from the test, returns to start up state menu to select a new test, and/or exits the software test system program.

FIGS. 20 through 22illustrate graphs of exemplary test data captured from a primer test performed by test system10ofFIG. 1. In one embodiment, the graphs ofFIGS. 20-22are provided in corresponding screens of GUI140ofFIG. 5for display to a user. Each ofFIGS. 20, 21, and 22depicts test data resulting from different functional parameters applied to the primer test.

InFIG. 20, the functional parameters applied to the primer included a 570 microsecond (μsec) pulse with a 60 VDC magnitude and an inline resistance of 96.5 kΩ. Graph300ofFIG. 20illustrates an exemplary electrical stimulus or firing pulse provided to the primer80, including the voltage (dashed line) and current (solid line) of the firing pulse versus time. The firing event illustratively ends at around 0.0015 microseconds. As such, graph300allows a user to verify that the correct voltage pulse width and amplitude as well as current were sent to the primer. A graph302illustrates the corresponding output characteristics of the primer versus time as a result of the electrical stimulus depicted in graph300, the outputs including pressure (solid line) and temperature (dashed line). The firing event of the primer illustratively occurs at around 0.0013 microseconds based on the pressure and temperature curves of graph302. With graphs300and302, a user may observe the amount of time it takes from application of the electrical pulse on the primer to the primer output (e.g., initiation and firing). As illustrated with graphs300and302, the primer fired at approximately 325 μsec following initial application of the 60 VDC firing pulse as evidenced by the pressure and temperature increases in graph302.

InFIG. 21, the functional parameters applied to the primer included a 570 microsecond (μsec) pulse at 50 VDC magnitude and an inline resistance of 16.4 kΩ. Referring toFIG. 21, a graph310illustrates an exemplary electrical stimulus or firing pulse provided to the primer80, including the voltage (dashed line) and current (solid line) of the firing pulse versus time. A graph312illustrates the corresponding output characteristics of the primer versus time as a result of the electrical stimulus depicted in graph310, the outputs including pressure (solid line) and temperature (dashed line). As illustrated in graphs310and312, the primer fired at approximately 150 μsec following initial application of the 50 VDC firing pulse as evidenced by the pressure and temperature increases in graph312.

InFIG. 22, the functional parameters applied to the primer included a 570 microsecond (μsec) pulse at 280 VDC magnitude and an inline resistance of 75.2 kΩ. Referring toFIG. 22, a graph320illustrates an exemplary electrical stimulus or firing pulse provided to the primer80, including the voltage (dashed line) and current (solid line) of the firing pulse versus time. A graph322illustrates the corresponding output characteristics of the primer versus time as a result of the electrical stimulus depicted in graph320, the outputs including pressure (solid line) and temperature (dashed line). As illustrated in graphs320and322, the primer fired at approximately 80 μsec following initial application of the 280 VDC firing pulse as evidenced by the pressure and temperature increases in graph322.

As observed fromFIGS. 20-22, the primer in each test condition fired within 570 μsec following initial application of the firing pulse. Further,FIGS. 20-22illustrate that primers with lower applied voltage and higher inline resistance exhibited longer action times in firing, while primers with higher applied voltage exhibited shorter times in firing. In one embodiment, an observer may conclude that foreign dirt or debris trapped between the firing pin and the primer may cause a reduction in the voltage at the primer leading to a longer action time in firing.

In one embodiment, the results of the test system analysis show a correlation between voltage, dwell time, and cartridge resistance and show which variables affect primer initiation and to what extent. In one embodiment, the results of the test system analysis provide an indication of whether the gun used to fire the tested primer or AUR contains dirt or debris affecting firing performance, whether the rounds are defective, whether the primer is defective, whether the firing pin area has a mechanical fault or misalignment, etc. In one embodiment, the number of pulses, pulse magnitude, pulse duration, and inline resistance selected by the user with test system10are used to simulate poor or intermittent contact of the firing pin with the electric primer during application of the firing pulse to the primer. In one embodiment, the varied inline resistance is used to simulate debris or a foreign object being between the firing pin of the gun and the primer that creates a voltage divider resulting in only a portion of the supplied voltage reaching the primer. In one embodiment, the number of pulses selected by the user with test system10may be used to simulate “chatter” or vibration between the firing pin and the electric primer (e.g., the pin skipping across the primer surface) during firing. In one embodiment, the input parameters varied by the user may be used to simulate a long action time for firing the primer or the AUR.

In one embodiment, the electric primer described herein and tested with testing system10ofFIG. 1is used in a cannon round (e.g., the M50 20 mm or other suitable round) of a military gun. Other suitable applications of the tested electric primer may be provided. While testing system10has been described herein for use with a primer or AUR, testing system10may be used to apply pulse signals to and test the output of other suitable electrically initiated gas generators.

The term “logic” or “control logic” or “software module” as used herein may include software and/or firmware executing on one or more programmable processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), hardwired logic, or combinations thereof. Therefore, in accordance with the embodiments, various logic may be implemented in any appropriate fashion and would remain in accordance with the embodiments herein disclosed.

The disclosed operations set forth herein may be carried out by one or more suitable processors that are in communication with non-transitory computer readable medium such as but not limited to CDROM, RAM, other forms of ROM, hard drives, distributed memory, etc. The non-transitory computer readable medium stores executable instructions that when executed by the one or more processors cause the one or more processors to perform, for example, the operations of computing device7described herein and/or the methods and software sequences as described with reference toFIGS. 7-18.