Patent Description:
The present disclosure relates generally to inflatable evacuation systems and, more particularly, to systems used to provide an indication readiness or sufficient inflation of such inflatable evacuation systems for use by passengers or crew.

Inflatable evacuation systems may be found on various structures, including aircraft, boats, offshore drilling platforms and the like. The systems are typically equipped with an inflatable or an inflatable device, such as, for example, an inflatable slide or an inflatable raft, configured to facilitate rapid evacuation of persons in the event of an emergency. Such inflatables are typically stored in an uninflated condition on the structure in a location readily accessible for deployment. For example, an evacuation slide for a commercial aircraft is stored in an uninflated condition in a case or compartment located proximate an emergency exit.

Systems used to inflate evacuation slides typically employ a gas stored within a cylinder or tank at high pressure, which is discharged into the evacuation slide (or into an inflatable tube comprised within the evacuation slide) within a specific time period. This may be accomplished, for example, by opening a main inflation valve that connects the high-pressure gas to the inflatable tube. Since fast inflation times for an evacuation slide or raft are important, most inflation systems will have excess gas in the storage cylinder or tank to ensure complete inflation and to adjust for variations in ambient temperature and gas supply lines. An evacuation slide is also typically provided with one or more pressure relief valves to vent the excess gas after the evacuation slide or inflatable tube is charged to the set pressure of the pressure relief valve.

During an emergency or similar event, the evacuation slide is typically deployed in response to an action taken by a passenger or a crew member. Upon deployment, the high-pressure gas is forced into the evacuation slide or the inflatable tube, causing inflation of the slide to occur. While inflatable evacuation systems are configured for fast inflation times, situations may occur where inflation takes more time than expected or the evacuation slide remains underinflated upon expiration of the high-pressure gas source. In such situations, it may be undesirable for passengers or crew members to board the evacuation slide, particularly where the device is currently undergoing inflation or assumes an underinflated state of readiness following inflation.

<CIT> describes a battery powered tyre pressure sensor system with a high sensitivity stretch sensor assembly. Other prior art systems are known from <CIT>, which describes an inflatable flotation device with a speaker generating a signal that it is ready to be used, and from <CIT>, which describes a tyre parameter measuring device comprising a pressure sensor and a temperature sensor fixed to or integrated in a substrate.

An inflation system for an inflatable is disclosed. The inflation sensor system includes a readiness indicator module; a stretch sensor configured for mounting to the inflatable and to provide a real-time stretch data of an elastic deformation of the inflatable; and a controller configured to receive the real-time stretch data and to transmit a control signal to the readiness indicator module to indicate a deployed status of the inflatable.

The system also includes a temperature sensor configured for mounting to the inflatable and to provide a real-time temperature data of the inflatable. In various embodiments, the controller includes a stretch-temperature database configured to compensate the real-time stretch data based on the real-time temperature data and to generate a compensated stretch signal. In various embodiments, the controller is configured to compare the compensated stretch signal against a cutoff pressure value and to activate the readiness indicator module once the compensated stretch signal indicates a pressure within the inflatable exceeds the cutoff pressure value. In various embodiments, the readiness indicator module includes a light source or an audio source.

In various embodiments, the controller is configured to compare the compensated stretch signal against the cutoff pressure value and to stop a flow of a pressurized gas to the inflatable if the compensated stretch signal indicates the pressure within the inflatable exceeds the cutoff pressure value. In various embodiments, the controller is configured to compare the compensated stretch signal against a cutoff stretch value and to stop a flow of a pressurized gas to the inflatable if the compensated stretch signal exceeds the cutoff stretch value.

An evacuation system for an aircraft is disclosed. The evacuation system includes an inflatable tube; a source of a pressurized gas; a valve module connected to the source of the pressurized gas and configured to control a flow of the pressurized gas to the inflatable tube, and an inflation sensor system as described above, wherein the controller is configured to transmit a control signal to the valve module to control the flow of the pressurized gas to the inflatable tube and to the readiness indicator module to indicate a deployed status of the inflatable tube. In various embodiments, the readiness indicator module includes a light source or an audio source. In various embodiments, the readiness indicator module is mounted on an exit door of the aircraft.

In various embodiments, the controller includes a stretch-temperature database configured to compensate the real-time stretch data based on the real-time temperature data and to generate a compensated stretch signal. In various embodiments, the controller is configured to compare the compensated stretch signal against a cutoff pressure value and to activate the readiness indicator module once the compensated stretch signal indicates a pressure within the inflatable tube exceeds the cutoff pressure value.

In various embodiments, the valve module includes a main pneumatic valve configured to start and to stop the flow of the pressurized gas. In various embodiments, the valve module includes a normally closed control valve connected to the controller and configured to operate the main pneumatic valve. In various embodiments, the controller is configured to compare the compensated stretch signal against a cutoff pressure value and to stop the flow of the pressurized gas to the inflatable tube if the compensated stretch signal indicates a pressure within the inflatable tube is greater than the cutoff pressure value. In various embodiments, the controller is configured to compare the compensated stretch signal against the cutoff pressure value and to start the flow of the pressurized gas to the inflatable tube if the compensated stretch signal indicates the pressure within the inflatable tube is less than the cutoff pressure value. In various embodiments, the controller is configured to compare the compensated stretch signal against a cutoff stretch value and to stop the flow of the pressurized gas to the inflatable tube if the compensated stretch signal exceeds the cutoff stretch value.

A method for controlling inflation of an inflatable is disclosed. In various embodiments, the method includes the steps of opening a valve module connected to a source of a pressurized gas and configured to control a flow of the pressurized gas to the inflatable; monitoring a stretch sensor mounted to the inflatable to provide a real-time stretch data of an elastic deformation of the inflatable; monitoring a temperature sensor mounted to the inflatable to provide a real-time temperature data of the inflatable; generating a compensated stretch signal based on a comparison of the real-time stretch data and the real-time temperature data against a thermal compensation database; and activating a readiness indicator module based on the compensated stretch signal having reached a threshold value indicating a deployed state of the inflatable. In various embodiments, the readiness indicator module includes a light source or an audio source.

The foregoing features and elements may be combined in any combination, without exclusivity, unless expressly indicated herein otherwise, to the extent that they fall within the claims.

Referring to <FIG>, an aircraft <NUM> having an evacuation slide <NUM> is illustrated, in accordance with various embodiments. The aircraft <NUM> may include a fuselage <NUM> with wings fixed to the fuselage <NUM>. An emergency exit door <NUM> may be disposed on the fuselage <NUM> over one of the wings or at some other location along a length of the fuselage <NUM>. As described further below, in various embodiments, a readiness indicator module <NUM> is mounted on the emergency exit door <NUM> and configured to provide a readiness indicator (e.g., via a light signal or an audio signal or both) during an inflation process once the evacuation slide is completely or otherwise safely deployed. The evacuation slide <NUM> and other components of an evacuation system may be housed within a pack-board housing or other compartment mounted to the aircraft <NUM>. The evacuation system may jettison a blowout panel to deploy the evacuation slide <NUM>, such as, for example, an inflatable evacuation slide, in response to the emergency exit door <NUM> opening or in response to another evacuation event. <FIG> schematically depicts the evacuation slide <NUM> in a deployed state, extending from the fuselage <NUM> of the aircraft <NUM>. During deployment, an inflatable tube <NUM> (or a plurality of inflatable tubes) is inflated using an inflation system that is typically configured to deliver a pressurized gas to the inflatable tube <NUM>. The evacuation slide <NUM> may comprise a sliding surface <NUM> secured to the inflatable tube <NUM> and configured for sliding passenger egress from the emergency exit door <NUM> of the aircraft <NUM> to a surface on the ground in the event of an evacuation on land or to a water surface in the event of an evacuation on a lake, river or ocean. In various embodiments, the evacuation slide <NUM> includes a longitudinal axis <NUM> that extends from a first or a proximal end <NUM> (or a head portion) to a second or a distal end <NUM> (or a foot portion). As described further below, in various embodiments, the evacuation slide <NUM> may comprise a stretch sensor <NUM> (or a plurality of stretch sensors) disposed on the inflatable tube <NUM> (or on each inflatable tube comprised within the evacuation slide <NUM>).

Referring now to <FIG>, an inflation control system <NUM> coupled to an inflatable, such as, for example, an evacuation slide <NUM> that is similar to the evacuation slide <NUM> described above, is illustrated. While the disclosure provided herein focuses on inflation of evacuation slides, it will be appreciated the inflation control system <NUM> may be applied to other inflatables, such as, for example, life-rafts or balloons or the like. Similar to the description above, the evacuation slide <NUM> may include an inflatable tube <NUM> and a proximal end <NUM> (or a head portion) configured for attachment to a structure, such as, for example, an aircraft, and a distal end <NUM> (or a foot portion) spaced a length of the evacuation slide <NUM> from the proximal end <NUM>. At least one stretch sensor <NUM> (two being shown in <FIG>) is mounted on the inflatable tube <NUM> and is configured to sense or monitor an elastic stretch or an elastic deformation of the fabric comprising the inflatable tube <NUM> during an inflation process. At least one temperature sensor <NUM> (two being shown in <FIG>) is also mounted on the inflatable tube <NUM> and is configured to sense or monitor the temperature of the inflatable tube <NUM> (or the ambient temperature surrounding the inflatable tube <NUM>) during the inflation process. Real-time data concerning the temperature of the inflatable tube <NUM> (or a real-time temperature data) and the elastic stretch experienced by the inflatable tube <NUM> (or a real-time stretch data) during the inflation process may then be used to determine the pressure within the inflatable tube <NUM> on a real-time basis during the inflation process. As described further below, the real-time temperature data and the real-time stretch data may likewise be used to determine an inflation status or readiness status of the inflatable tube <NUM> or the evacuation slide <NUM>.

Still referring to <FIG>, the inflation control system <NUM> includes a valve module <NUM>, a storage vessel <NUM> filled with a high-pressure gas (or, in various embodiments, a gas generator configured to generate a high-pressure gas), an aspirator <NUM>, a controller <NUM> and a power source <NUM>, such as, for example, a battery or charged capacitor. In various embodiments, the power source <NUM> is a dedicated source configured to power the stretch sensor <NUM> and the temperature sensor <NUM> mounted on the inflatable tube <NUM>, as well as each of the valve module <NUM> and the controller <NUM>. To provide a dedicated source of direct current power, the power source <NUM> may comprise, for example, a lithium-ion battery or an ultracapacitor, each configured to store energy at a high density for controlling the rapid sequence of events that occur during an inflation process of the evacuation slide <NUM>. As illustrated in <FIG>, real-time data from the stretch sensor <NUM> is transmitted to the controller <NUM> via a stretch sensor bus <NUM>, while real-time data from the temperature sensor <NUM> is transmitted to the controller via a temperature sensor bus <NUM>. In various embodiments, the controller <NUM> may include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or some other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. As described further below, in various embodiments, a readiness indicator module <NUM> is configured to receive an output signal from the controller <NUM> via an output signal bus <NUM> and to provide a readiness indicator (e.g., via a light signal or an audio signal or both) during an inflation process once the evacuation slide <NUM> is completely or otherwise safely deployed. The disclosure contemplates the output signal bus <NUM>, in various embodiments, to comprise a hard-wired bus (e.g., a copper-wired bus) or a wireless bus (e.g., a wireless communication link based on infrared, radio frequency, Zigbee, WiFi, etc.).

In further detail, the valve module <NUM> is configured to open and close a main pneumatic valve <NUM> based on a control signal received from the controller <NUM>. More specifically, based on preset control logic (that is typically specific to the materials used to construct a particular inflatable) and the real-time data received from the stretch sensor <NUM> and the temperature sensor <NUM>, the controller <NUM> opens or closes the main pneumatic valve <NUM> in order to turn on or turn off the flow of high-pressure gas from the storage vessel <NUM>, to the aspirator <NUM> and then to the inflatable tube <NUM> of the evacuation slide <NUM>. In various embodiments, the valve module <NUM> may further comprise a normally closed control valve <NUM>, such as, for example, a three-way, two-position normally closed control valve configured to operate the main pneumatic valve <NUM> between an open position and a closed position. In various embodiments, the valve module <NUM> may also include a pressure regulator valve <NUM> configured to prevent the occurrence of an over-pressure situation at the aspirator <NUM> or the inflatable tube <NUM>.

Referring now to <FIG>, a stretch sensor <NUM>, similar to the stretch sensor <NUM> described above with reference to <FIG>, is illustrated. The stretch sensor <NUM> includes a sensing material <NUM>, which may be either capacitance-based or resistance-based. For example, in various embodiments, the sensing material <NUM> comprises a capacitance-based material. Such capacitance-based stretch sensors exhibit minimal hysteresis during cyclic and creep tests and behave similar to a flexible parallel plate capacitor, comprising two conductive electrodes separated by a di-electric. When the stretch sensor <NUM> is stretched, its capacitance increases proportionate to the amount of stretch to which it is subjected. The stretch sensor <NUM> includes a first mounting tab <NUM> and a second mounting tab <NUM>, between which the sensing material <NUM> is disposed. In various embodiments, the first mounting tab <NUM> is attached to an inflatable tube <NUM> (similar to the inflatable tube <NUM> described above) via a first adhesive backing member <NUM>. Similarly, the second mounting tab <NUM> is attached to the inflatable tube <NUM> via a second adhesive backing member <NUM>. In various embodiments, the first mounting tab <NUM> includes a first aperture <NUM> configured to engage a first standoff pin <NUM> extending from the first adhesive backing member <NUM> and the second mounting tab <NUM> includes a second aperture <NUM> configured to engage a second standoff pin <NUM> extending from the second adhesive backing member <NUM>. A stretch sensor bus <NUM> (similar to the stretch sensor bus <NUM> described above) is connected to the sensing material <NUM> and configured to receive power from and to transmit real-time sensor data to a controller, such as the controller <NUM> described above. As the two mounting tabs move apart from one another as a result of the inflatable tube <NUM> being elastically deformed, the sensing material <NUM> will stretch and generate an electrical signal (or control signal) proportional to the degree of stretch, with the electrical signal transmitted to the controller via the stretch sensor bus <NUM>. In various embodiments, the elasticity of the sensing material <NUM> will generally be greater than the elasticity of the inflatable tube <NUM>, so as not to provide interference or resistance against the elastic deformation of the inflatable tube <NUM>.

In various embodiments, the stretch sensor <NUM>, when coupled to the inflatable tube <NUM>, is covered by a pouch <NUM> that may also be adhered to the inflatable tube <NUM>. The pouch <NUM> protects the stretch sensor <NUM> from harsh environments, such as, for example, saltwater. As described above, in various embodiments, the stretch sensor <NUM> is mounted to the inflatable tube <NUM> using the first standoff pin <NUM> and the second standoff pin <NUM>. However, in various embodiments, the first mounting tab <NUM> and the second mounting tab <NUM> may be bonded directly to the fabric of the inflatable tube <NUM>. Regardless of the manner of mounting, in various embodiments, the stretch sensor <NUM> may be mounted to the inflatable tube <NUM> with a slight amount of pre-stretch to account for manufacturing tolerances between the mounting tabs. The nominal output of the stretch sensor <NUM> may then be reset to zero or offset-corrected during a calibration process with an inflation control system, such as, for example, the inflation control system <NUM> described above.

During a calibration process, the stretch sensor <NUM> is calibrated to establish a functional relationship between a degree of stretch and a degree of electrical output or signal strength reflective of the degree of stretch. The calibration is performed over a range of temperatures likely to be encountered during an inflation process. Based on the calibration process, a stretch-temperature database (or a thermal compensation database) is developed and embedded into the controller. The stretch-temperature database will generally include information defining a relationship between the degree of stretch provided by the stretch sensor <NUM> as a function of temperature sensed by the temperature sensor. In other words, the stretch-temperature database will enable the controller to determine a value of pressure within the inflatable tube <NUM> based on two values - the degree of stretch reported by the stretch sensor <NUM> and the temperature of either the inflatable tube <NUM> or the ambient temperature surrounding the inflatable tube <NUM>. In various embodiments, the stretch-temperature database will include a cutoff pressure value that is equivalent or approximately equivalent to a pressure relief value used in pressure relief valves attached to currently used systems, thereby obviating the need to incorporate pressure relief valves into the inflatable tube <NUM>. As described further below with reference to <FIG>, rather than a cutoff pressure value, the stretch-temperature database may include a cutoff stretch value that may provide a more direct comparison against the degree of stretch reported by the stretch sensor <NUM>. Generally speaking, the cutoff pressure value and the cutoff stretch value will be indicative of equivalent levels of pressure within the inflatable tube <NUM>.

Referring now to <FIG>, an inflation readiness system <NUM> is illustrated, in accordance with various embodiments. The inflation readiness system <NUM> is coupled to an inflatable, such as, for example, an evacuation slide <NUM> that is similar to the evacuation slide <NUM> described above. Similar to the description above, the evacuation slide <NUM> may include an inflatable tube <NUM> and a proximal end <NUM> (or a head portion) configured for attachment to a structure, such as, for example, an aircraft, and a distal end <NUM> (or a foot portion) spaced a length of the evacuation slide <NUM> from the proximal end <NUM>. At least one stretch sensor <NUM> is mounted on the inflatable tube <NUM> and, as described above, is configured to sense or monitor an elastic stretch or an elastic deformation of the fabric comprising the inflatable tube <NUM> during an inflation process. At least one temperature sensor <NUM> is also mounted on the inflatable tube <NUM> and, as also described above, is configured to sense or monitor the temperature of the inflatable tube <NUM> (or the ambient temperature surrounding the inflatable tube <NUM>) during the inflation process. Real-time data concerning the temperature of the inflatable tube <NUM> (or a real-time temperature data) and the elastic stretch experienced by the inflatable tube <NUM> (or a real-time stretch data) during the inflation process may then be used to determine the pressure within the inflatable tube <NUM> on a real-time basis during the inflation process. The real-time temperature data and the real-time stretch data is also used to determine an inflation status or readiness status of the inflatable tube <NUM> or the evacuation slide <NUM>.

Still referring to <FIG>, the inflation readiness system <NUM> is incorporated into a system comprising a valve module <NUM>, a storage vessel <NUM> filled with a high-pressure gas (or, in various embodiments, a gas generator configured to generate a high-pressure gas), an aspirator <NUM>, a controller <NUM> and a power source <NUM>, such as, for example, a battery or charged capacitor. Each of the valve module <NUM>, the storage vessel <NUM>, the aspirator <NUM>, the controller <NUM> and the power source <NUM> is similar to the valve module <NUM>, the storage vessel <NUM>, the aspirator <NUM>, the controller <NUM> and the power source <NUM> described above with reference to <FIG>. In operation, a real time data from the stretch sensor <NUM> is transmitted to the controller <NUM> via a stretch sensor bus <NUM>, while a real-time data from the temperature sensor <NUM> is transmitted to the controller <NUM> via a temperature sensor bus <NUM>. In various embodiments, the controller <NUM> may include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or some other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

During an inflation process, and once the evacuation slide <NUM> is completely or otherwise safely deployed, an output signal from the controller <NUM> is provided to a readiness indicator module <NUM> via an output signal bus <NUM>. The disclosure contemplates the output signal bus <NUM>, in various embodiments, to comprise a hard-wired bus (e.g., a copper-wired bus) or a wireless bus (e.g., a wireless communication link based on infrared, radio frequency, Zigbee, WiFi, etc.). The readiness indicator module <NUM> is typically positioned on or in the vicinity of an emergency exit door of an aircraft, such as, for example, the emergency exit door <NUM> described above with reference to <FIG>. In various embodiments, the readiness indicator module <NUM> includes a receiver circuit <NUM> and a readiness indicator <NUM>. The readiness indicator <NUM> may include, for example, a visual indicator <NUM> (e.g., a light source) or an audio indicator <NUM> (e.g., an audio source). As described in further detail below with reference to <FIG>, as the evacuation slide <NUM> is being inflated, the real-time stretch data and the real-time temperature data is used to control inflation of the evacuation slide <NUM> and is also used to monitor readiness of the inflatable slide <NUM> for use. Once the controller <NUM> determines the evacuation slide <NUM> is completely or otherwise safely deployed, the output signal from the controller <NUM> is provided to a readiness indicator module <NUM> and either the visual indicator <NUM> or the audio indicator <NUM> or both are activated.

Referring now to <FIG>, a flowchart <NUM> describing a method for controlling inflation of an inflatable or an evacuation slide is provided. In describing the various steps, reference is made to the components of the inflation control system <NUM> described above with reference to <FIG> and the inflation readiness system <NUM> described above with reference to <FIG>. In a first step <NUM>, a decision to inflate the evacuation slide <NUM> (or the evacuation slide <NUM>) is made and reported to the controller <NUM> (or the controller <NUM>). At a second step <NUM>, the controller <NUM> transmits a control signal to the valve module <NUM> to open the main pneumatic valve <NUM>. In various embodiments, opening the main pneumatic valve <NUM> is accomplished by activating the normally closed control valve <NUM>. Following opening the main pneumatic valve <NUM>, the evacuation slide <NUM> begins pressurization at a third step <NUM>. At a fourth step <NUM> and a fifth step <NUM>, the controller <NUM> reads real-time data from the stretch sensor <NUM> and the temperature sensor <NUM>. The real-time data from the stretch sensor <NUM> and the temperature sensor <NUM> is then compared against a stretch-temperature database (or a thermal compensation database <NUM>) and compensated to provide a compensated stretch signal according to the temperature reported by the temperature sensor <NUM> at a sixth step <NUM>.

At a seventh step <NUM>, the compensated stretch signal is compared against a cutoff pressure value (e.g., the cutoff pressure value that is equivalent or approximately equivalent to the pressure relief value used in current systems). If the compensated stretch signal indicates a pressure within the inflatable tube <NUM> is less than or equal to the cutoff pressure value, then the controller <NUM> performs a query at an eighth step <NUM> to determine the status of the main pneumatic valve. If the main pneumatic valve <NUM> is open, then the controller <NUM> continues pressurization of the inflatable tube <NUM> using the current configuration, or, if the main pneumatic valve <NUM> is closed, then the controller <NUM> returns to the second step <NUM>, where the main pneumatic valve <NUM> is re-opened and the inflation process continues. Returning to the seventh step <NUM>, if the compensated stretch signal indicates a pressure within the inflatable tube <NUM> is greater than the cutoff pressure value, then the controller <NUM> directs the main pneumatic valve <NUM> to close, thereby halting the flow of pressurized gas to the inflatable tube <NUM> at a ninth step <NUM>. Likewise, if the compensated stretch signal is less than or equal to a cutoff stretch value, then the controller <NUM> performs the query at the eighth step <NUM> and continues operation as described above and if, on the other hand, the compensated stretch signal is greater than the cutoff stretch value, then the controller <NUM> directs the main pneumatic valve <NUM> to close, thereby halting the flow of pressurized gas to the inflatable tube <NUM> at the ninth step <NUM>. Once the compensated stretch signal indicates a pressure within the inflatable tube <NUM> is greater than the cutoff pressure value (or the cutoff stretch value), then the controller <NUM> (or the controller <NUM>) also directs the readiness indicator module <NUM> (or the readiness indicator module <NUM>) to be activated at a tenth step <NUM>.

As illustrated in the flowchart <NUM>, regardless of whether the flow of pressurized gas to the inflatable tube <NUM> continues or is halted, the monitoring of the stretch sensor <NUM> and the temperature sensor <NUM> continues in a cyclic fashion, enabling the controller <NUM> to open and close the main pneumatic valve <NUM> in real-time during the inflation process depending on fluctuations of the pressure within the inflatable tube <NUM>. For example, after the main pneumatic valve <NUM> is closed, if the compensated stretch signal indicates a pressure within the inflatable tube <NUM> has decreased to less than the cutoff pressure value (or the stretch cutoff value), then the controller <NUM> opens the main pneumatic valve <NUM> again to continue the flow or pressurized gas to the inflatable tube <NUM>. Accordingly, the compensated stretch signal becomes a control variable, where the pressure within the inflatable tube <NUM> (or the stretch value representative of deformation of the inflatable tube <NUM>) is maintained within a tolerance band during the inflation process by actuating and de-actuating the main pneumatic valve <NUM> for one or more cycles. In such fashion, the main pneumatic valve <NUM> may be operated in a pulse-width controlled manner to maintain the pressure (or the degree of stretch) within the tolerance band. Note that while the inflation process may continue in the cyclic fashion just described, once the compensated stretch signal first indicates a pressure within the inflatable tube <NUM> is greater than the cutoff pressure value and the readiness indicator module <NUM> (or the readiness indicator module <NUM>) has been activated, the readiness indicator module <NUM> remains in the activated state (i.e., the visual indicator <NUM> or the audio indicator <NUM> or both remain activated).

The inflation readiness system described above, in conjunction with the inflation control system, provides a readiness indication status of an evacuation slide in the deployed condition and establishes a confirmed and safe evacuation status at each exit door for passengers disembarking an aircraft during an emergency. The disclosed systems employ flexible stretch sensors bonded to an inflatable tube, typically disposed proximate the foot portion of the inflatable tube. Because the output values of the stretch sensors may vary as a function of ambient temperature, temperature compensation is introduced using temperature sensors. Note the disclosure contemplates stretch and temperature sensors that may be connected to a controller via wired or wireless buses, which, in various embodiments, may comprise a hard-wired bus (e.g., a copper-wired bus) or a wireless bus (e.g., a wireless communication link based on infrared, radio frequency, Zigbee, WiFi, etc.). A readiness indicator within the aircraft, which may also be connected to the controller via wired or wireless buses, may be activated once the controller determines the stretch sensor has reached a threshold value indicative of the evacuation slide having assumed a deployed status (e.g., fully deployed) or otherwise safe condition (e.g., partially deployed but still considered safe).

Numbers, percentages, or other values stated herein are intended to include that value, and also other values that are about or approximately equal to the stated value, as would be appreciated by one of ordinary skill in the art encompassed by various embodiments of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable industrial process, and may include values that are within <NUM>%, within <NUM>%, within <NUM>%, within <NUM>%, or within <NUM>% of a stated value. Additionally, the terms "substantially," "about" or "approximately" as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the term "substantially," "about" or "approximately" may refer to an amount that is within <NUM>% of, within <NUM>% of, within <NUM>% of, within <NUM>% of, and within <NUM>% of a stated amount or value.

Claim 1:
An inflation sensor system for an inflatable, comprising:
a readiness indicator module (<NUM>);
a stretch sensor (<NUM>) configured for mounting to the inflatable and to provide a real-time stretch data of an elastic deformation of the inflatable; and
a controller (<NUM>) configured to receive the real-time stretch data and to transmit a control signal to the readiness indicator module to indicate a deployed status of the inflatable; and characterized by:
a temperature sensor (<NUM>) configured for mounting to the inflatable and to provide a real-time temperature data of the inflatable.