Dynamic adjustment of circumaural acoustic cup fitment in aviation helmets

Abstract

A helmet includes a shell configured to extend over user ears, earcups disposed within the shell, and an ear cushion / seal for each earcup. One or more electro-mechanical actuators couples each earcup to the helmet shell and is controlled by a controller to adjust z-axis (side) position and associated pressure acting on the user's head responsive to signals from one or more sensors mounted on or in the helmet. Sensors may include an internal microphone detecting sound levels within the earcup and an external microphone detecting sound outside of the earcup and / or helmet. Earcups may include speakers / drivers connected to the controller to provide active noise reduction / cancellation and audio communications. The controller may periodically reduce side pressure via the actuators to provide comfort cycling and reduce user fatigue. Comfort cycling may be performed during quieter portions of a flight, or when noise dosimetry data is below a corresponding acceptable threshold.

Description

DYNAMIC ADJUSTMENT OF CIRCUMAURAL ACOUSTIC CUP FITMENT IN AVIATION HELMETSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Application No. 63 / 709,526 filed October 21, 2024, the disclosure of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] This application relates to adjustment of acoustic cup fitment by a programmed controller or processor associated with an aviation helmet by controlling actuators in response to signals from one or more microphones, sensors, and / or user inputs.BACKGROUND

[0003] Helmets are worn to protect the head of the user from injuries that may occur in a wide variety of aviation applications including commercial and military applications. The helmet design may vary depending on the type and frequency of expected impacts. Similarly, use patterns may vary from repeated removal of the helmet between short duration uses of less than an hour, to extended periods of use over several hours. In addition to impact protection, helmets may be designed to reduce transmission of external sound while optimizing operational communications. Active audio devices such as speakers and microphones and / or passive devices such as acoustic sound absorbing material may be used alone or in combination to provide the desired helmet acoustics.

[0004] In passive and active noise reduction helmet applications, performance and wearability may be improved by providing a complete seal around the ears without compromising comfort over long use durations. Current helmet designs appear to lack the ability to achieve these seal and comfort goals without significant tradeoffs between them.

[0005] A variety of non-military helmets and others that do not include fully customized shells provide adjustable earcups. However, the earcup assembly is mounted and positioned within the helmet using a repositionable or removable fastener, such as a hook and loop closure. The external shell is a hard molded shape with the earcup assembly moveable within the inner lining of the shell. Foam pads and strips of hook and loop closure material is used to provide a customized fit for each user. These types of positioning systems require that the helmet be removed to position the earcup assembly and comfortable positioning often requires several trial-and-error attempts by the user. These systems are also generally fixed or static once positioned within the helmet, although repeatedly wearing and removing the helmet may disturb the positioning of the acoustic earcups. In addition, side pressure is established by the external shell dimension and the selection or combination of padding positioned through this iterative process.[0006| Helmets having active noise reduction (ANR) technology to cancel at least some of the unwanted external noise rely on a good seal around each ear to achieve best results. A good seal is particularly difficult to achieve inside a helmet for at least two reasons: helmets generally fit fairly tightly to provide their protective function, and the ear pinna protrudes from the surrounding surfaces of the head and varies in shapes and sizes among users. As such, donning the helmet and proper positioning of previously placed earcups or earphones can be very challenging. After the helmet is placed on the head, the seal around the ear may not be ideal based on ear position (within the earcup) or the earcup position relative to the skull. To achieve desired acoustic performance, users may over-compensate for acoustic leak paths by increasing the side pressure, which may result in reduced comfort, particularly over long periods of time. In military applications, environmental factors including ambient sound levels, barometric pressure, and g-forces may vary considerably depending on the type of aircraft and mission.

[0007] For best performance of an ANR. system, the positioning of the ear canal and pinna relative to the driver / speaker and ANR. feedback microphone within the earcup or earphones should be understood and repeatable. Current solutions generally fail to deliver consistent performance and comfort with either the acoustics or the cushion / seal system. Largely due to positioning and comfort constraints previously described, existing helmets use a full round / oval seal. Although slot seals may reduce circumference / perimeter distance and result in greater comfort, slot seals may be unsuitable for many helmet applications due to the difficulty inpositioning the pinna into the ear slot seal when donning the helmet due to the fixed earcup within the helmet. Existing ear cushion / seals may apply a uniform pressure distribution that may contribute to discomfort while also creating acoustic leak paths. Furthermore, helmets without independent suspension systems do not improve sealing performance in response to downward pressure from tightening a chin strap, for example.

[0008] As used herein “fitment” generally refers to the way an aviation helmet and its integrated wearable acoustic system are positioned to provide desired noise protection, comfort, and optimal communication to maximizing aviator mission effectiveness. Existing static fitment is a trial and error process in an equipment room that does not ensure optimal side pressure / comfort performance during operations, does not ensure adequate noise protection, and does not provide wearability relief during flight operations without manual intervention which may lead to unnecessary fatigue and resulting distraction reducing mission effectiveness.

[0009] While aviation headsets typically provide dynamic fitment adjustments using a spring-biased headband that applies variable z-axis side-pressure to acoustic cups attached by a pivot and gimbal in combination with foam ear cushions / seals to provide x-axis and y-axis adjustments, helmets are typically fitted for a cranial shape first, and then the acoustic cup placement or position is established based on the ear position relative to the helmet shell. There is no automatic adjustment that adapts to the head shape of the face and jaw. Instead, x-axis and y-axis positioning is done manually around the ear based on helmet sizing using positionable pads of selectable thickness(es) to adjust the z-axis side pressure. This is a manual trial and error process that is not performed under operational conditions and is therefore static or fixed while operational noise and flight conditions may vary considerably throughout a particular mission especially relative to the conditions of the equipment fitting room conditions.

[0010] Headsets and helmets for various applications have incorporated inflatable bladders to provide a manually or automatically adjustable fitment. The bladders may be inflated with a fluid, such as air or liquid, to increase side pressure and deflated to decrease side pressure. This strategy may be unsuitable for aviation applications that may encounter significant fluctuations in barometric pressure (atmospheric and / or cabin pressure) and g-forces and which require repeatable, reliable, and durable operation under repeated cycling. Similarly, any leaking of air or liquid from such bladders may pose operational safety issues and would be unacceptable for usein commercial and military aviation applications. Likewise, additional mass of liquids and shifting of mass center of gravity when subjected to changing g-forces may impose undesirable distractions and movements / resistance to movement on pilots in demanding applications.

[0011] The field of audio dosimetry includes devices that measure noise environments to characterize a more detailed story of noise exposure in a particular workspace. That data may be used to suggest that hearing protection is required to meet regulatory safety standards. While helpful to predict threshold noise levels (sound pressure levels or SPLs) needing a solution, that information is only loosely correlated to a specific user, and the user’s actual noise exposure for each ear over the timeframes of their total work / mission.

[0012] At least one commercially available wearable audio dosimeter provides an in-the-ear (earplug) configuration with a microphone. This device gathers audio dosing data to track and ensure adequate ear-plug fit. The device may be used by safety officers alone or in combination with a portable sound pressure level meter and wearable monitoring buttons or sensors to gather data on noise exposure of a worker’s area to compile an 8-hour Total Weighted Average (TWA) exposure number. This data can be used to implement a safety plan for selection of appropriate hearing protection devices (HPD) and exposure time limits to meet regulatory agency requirements based on assumed attenuation levels delivered by the HPD. However, studies have suggested that users may not consistently achieve the level of noise reduction of various types of HPD as the noise reduction specified for those devices under laboratory testing conditions rather than in-use measurements where changing fitment of the HPD in real-world use scenarios may adversely impact effectiveness and result in higher than anticipated noise dosing. This may result in otherwise preventable hearing loss to users.

[0013] Hearing loss is a complex phenomenon that may result from a variety of noise exposure factors including the peak loudness, frequency, and time of exposure to noise. While these factors may be studied and analyzed for particular environments, work areas, or application zones to determine guidelines or specifications and related recommended equipment to protect users from hearing loss, the dynamic nature of many real-world situations makes it difficult to determine whether a particular person is currently being exposed, or has been experiencing a cumulative noise exposure that could result in short-term or long-term hearing loss and related conditions until it is too late for preventive interventions. Without timely personalized noise dosinginformation (whether real-time or post-exposure), it is difficult to determine the root cause or leading factors contributing to potentially damaging overexposure. For example, it may be difficult to determine if the user has experienced dangerous noise dosing and whether the noise reaching the ears of the user was due to an increase in the environmental noise, or a reduction in effectiveness of a protective device associated with poor fitment, user error, device inoperability, device degradation or excessive wear, etc. This makes it difficult or impossible to alert the user and / or a manager or supervisor to a potential concern or to apply manual or automatic remediating interventions.

[0014] While limiting time of exposure to noise may reduce the potential for hearing loss, many industrial, commercial, or military applications are not particularly amenable to such constraints.SUMMARY

[0015] In one or more aspects of the present disclosure, dynamic fitment adjustment is controlled by a programmed controller in response to short duration and / or long duration feedback to improve effectiveness of HPD. In one representative example, an a helmet includes a shell configured to extend over ears of a user, a pair of earcups disposed within the shell, and an ear cushion / seal connected to each earcup. One or more electro-mechanical actuators couples each earcup to the helmet shell and is controlled by a processor to adjust z-axis (side) position and associated pressure acting on the head of a wearer responsive to signals from one or more sensors mounted on or in the helmet. In various embodiments, the sensors include an internal microphone configured to detect sound / acoustic pressure levels within an associated earcup and an external microphone configured to detect sound / acoustic pressure levels outside of the earcup and / or helmet. Each earcup may include one or more speakers / drivers controlled by the processor to provide active noise reduction / cancellation (ANR / ANC), as well as to generate audio communications to the wearer. The actuators may be controlled to periodically reduce side pressure to provide “comfort cycling” and reduce fatigue for the wearer. Comfort cycling may be performed during quieter portions of a flight, or when noise dosimetry data is below a corresponding acceptable threshold, for example.

[0016] According to one aspect of the disclosure, a helmet having integrated earcups coupled to a helmet shell by one or more processor-controlled actuators configured to adjust side pressure of an ear cushion / seal as previously described with one or more of the earcups including active noise reduction (ANR) components, which may include one or more microphones, speakers / drivers, programmed microprocessors, memory and / or electronics to provide active noise reduction.

[0017] According to one aspect of the disclosure, an aviation helmet includes a shell configured to extend over ears of a user, circumaural earcups disposed within the shell, each of the earcups having an ear seal, an error sense microphone, an ambient microphone, and a speaker, at least one electromechanical actuator associated with each of the earcups, the actuator configured to move at least a portion of an associated earcup relative to the shell, and at least one controller in communication with the error sense microphones, the ambient microphones, the speakers, and the at least one electromechanical actuator, the at least one controller programmed to control the at least one electromechanical actuator in response to signals from one or more of the error sense microphones and the ambient microphones. The at least one controller may be programmed to control the at least one electromechanical actuator to increase distance between at least a portion of the associated earcup and the shell in response to signals from at least one of an associated error sense microphone and an associated ambient microphone that correspond to increasing sound pressure level (SPL). In some applications, two or more actuators are associated with corresponding portions of each earcup to provide more granular control of side pressure and may be positioned near areas commonly associated with acoustic leak paths. The controller may be programmed to process signals from the error sense microphones and the ambient microphones to generate signals for the speakers that provide active noise reduction. The controller(s) may be programmed to control the at least one electromechanical actuator to periodically decrease distance between at least a portion of the associated earcup and the shell for a predetermined time period to increase wearer comfort and reduce fatigue. The controller may be programmed to suspend periodically decreasing the distance while sound pressure level (SPL) detected by at least one of the error sense microphones and the ambient microphones exceeds a corresponding SPL threshold. One or more thresholds may be stored in memory accessible by the controller and retrieved in response to a particular mission or current flight conditions, for example. Signals from one or more error sense microphones and / or ambient microphones may be processed by one or more controllersto generate audio dosimetry data used by the controller to dynamically adjust earcup fitment either alone or in combination with shorter duration SPLs detected by the microphone(s).

[0018] According to various aspects of the disclosure, the controlled s) is programmed to control the at least one electromechanical actuator to decrease distance between at least a portion of the associated earcup and the shell until signals from the associated error sense microphone indicate sound pressure level exceeding a previously stored SPL threshold. The controller(s) may be programmed to control the at least one electromechanical actuator to decrease distance between at least a portion of the associated earcup and the shell in response to signals from at least one of an associated error sense microphone and an associated ambient microphone that correspond to sound pressure level (SPL) being below a previously stored SPL threshold.

[0019] In other aspects, the aviation helmet includes at least one ambient microphone positioned to detect ambient sound external to the earcups and / or external to the helmet. The controller(s) may be configured to receive voice communication signals with at least one controller further programmed to control the at least one electromechanical actuator to move at least a portion of the earcups to increase distance between the earcups and the shell and corresponding side pressure in response to receiving voice communication signals.

[0020] According to various aspects, an aviation helmet includes a user input configured to receive requests for earcup pressure adjustments, wherein the at least one controller is further programmed to control the at least one electromechanical actuator in response to the user input. The helmet may also include a communication microphone coupled to the at least one controller, wherein the user input comprises the communication microphone. User input may be received from a wired input such as a microphone, pushbutton, or switch, or via a wirelessly coupled user interface, such as a smartphone app, for example.

[0021] According to another aspect of the disclosure, the controller(s) are further programmed to limit earcup pressure adjustments requested via the user input that decrease distance between the earcups and the shell to reduce side pressure in response to signals from at least one of the error sense microphones and the ambient microphones indicating sound pressure level exceeding a corresponding SPL threshold.

[0022] In various representative examples, the electromechanical actuator includes a base fixed to an interior of the helmet shell and a portion extending through an aperture of the shell to facilitate movement of the earcup using the portion extending through the shell. A solenoid is connected to the portion extending through the aperture and is coupled to the at least one controller. The electromechanical actuator(s) may be positioned within the shell between the earcups and the shell, or may be positioned with some components within the shell coupled to components external to the shell depending on the particular implementation. The solenoid may be controlled by the at least one controller to move an associated earcup toward and away from the shell using the portion extending through the shell to adjust side pressure of the earcup during use of the helmet. In various embodiments, the at least one controller controls the solenoid to move the associated earcup away from the shell to increase side pressure of the earcup during use of the helmet based on signals from at least one of the error sense microphones and the ambient microphones indicating sound pressure level (SPL) exceeding an associated SPL threshold.

[0023] In another aspect of the disclosure, a method for adjusting fitment of ear seals of circumaural earcups within an aviation helmet includes controlling at least one electromechanical actuator by a programmed controller to automatically move the earcups toward or away from a shell of the aviation helmet to adjust side pressure of the earcups and ear seals on the head of a wearer in response to feedback signals from at least one microphone. The method may include controlling the at least one actuator to move the earcups away from the shell in response to the at least one microphone detecting sound pressure level (SPL) exceeding a corresponding threshold. One or more thresholds may be stored in a memory accessible by the controller and retrieved based on one or more operating conditions. The microphones may include an error sense microphone positioned within each of the earcups. At least one microphone may be an ambient microphone positioned to detect sound outside of the earcups and / or outside of the helmet.

[0024] In one aspect of the disclosure, the method includes controlling the at least one actuator to periodically move the earcups toward the shell to reduce side pressure to increase wearer comfort and reduce fatigue. The actuator may be controlled to periodically move the earcups toward the shell to reduce side pressure for a programmable period of time. In another aspect, the at least one actuator is controlled to periodically move the earcups toward the shell to reduce side pressure until the at least one microphone detects sound pressure level inside the earcupexceeding a corresponding threshold. In this aspect, the controller automatically optimizes wearer comfort while maintaining noise exposure levels below a specified threshold, which may vary through a particular flight based on accumulated noise dosing, for example. The method may also include suspending periodically moving the earcups toward the shell in response to the at least one microphone detecting sound pressure level inside the earcup exceeding a corresponding threshold, and resuming periodically moving the earcups toward the shell in response to the at least one microphone detecting sound pressure level inside the earcup being equal to or below the corresponding threshold. In various examples of the method, the microphones include an error sense microphone positioned within each of the earcups and an ambient microphone associated with each of the earcups and positioned to detect sound outside of the earcups. The method may also include processing signals, by the controller, from the error sense microphones and the ambient sense microphones and generating active noise reduction (ANR) signals communicated to a speaker within each of the earcups.

[0025] Other aspects of the disclosure include a system comprising headgear with first and second circumaural earcups. An internal microphone is disposed within at least one of the first and second earcups. An external microphone is positioned or otherwise configured to provide a signal indicative of noise outside of the earcup. The internal and external microphones are in communication with a programmed controller or processor and memory configured to process and store noise exposure data based on signals from the internal and external microphones. The noise exposure data may be processed by the (local) processor or a remote processor to generate an alert in response to detecting one or more characteristics of the exposure data exceeding associated thresholds. The noise exposure data may be processed to detect a correlation between signals from the internal and external microphones. The processor may programmed or configured to generate a fitment alert in response to the correlation being below a corresponding threshold. The fitment alert may be used to automatically adjust fitment of one or both earcups by controlling one or more associated electromechanical actuators, or may be communicated to a user via visual, audio, or haptic indicator. The noise exposure data may include loudness or amplitude, frequency or frequency spectrum, and associated time of exposure. The noise exposure data may be processed to generate various statistical parameters or noise exposure parameter measurements. In one or more embodiments a time-weighted average (TWA) of exposure is generated. The local processor may wirelessly communicate the noise exposure data and / or related parameters, characteristics, oralerts to the remote processor. The remote processor may include a smart phone, an aviation computer or instrument panel, or an internet cloud server or storage device.

[0026] According to various aspects of the disclosure, headgear having integrated audio dosimetry provides active noise reduction (ANR). Each earcup includes a driver or speaker in communication with the processor. The processor is configured to generate a reduction or cancellation signal for each driver having an amplitude and phase based on the signal detected by the associated internal microphone. The cancellation signal may also be based on the signal detected by the associated external microphone. In various embodiments, the processor is configured to provide adaptive noise cancellation with a feedforward control signal provided by the external microphone and a feedback signal provided by the internal microphone. Use of ANR strategies may improve the effectiveness of hearing protection, but may also subject the user to higher noise exposure associated with sub-optimal fitment, user error, or component inoperability or failure absent integrated dosimetry and corresponding automatic fitment adjustments by a controller coupled to one or more electromagnetic actuators according to various aspects of the disclosure.

[0027] Various embodiments may provide a personalized hearing loss assessment or indicator based on the noise exposure data captured by the internal microphones. A baseline assessment of hearing at selected frequencies may be stored with feedback from a user input or connected smart phone app. The baseline measurements may be stored for subsequent reference and comparison to provide early detection of hearing degradation and alert the user or other personnel. This hearing assessment or profile as determined by the headgear may also be used by the same headgear to customize signals delivered by the speaker / driver to improve intelligibility of speech or other types of sounds in high-noise environments while attenuating extraneous noise.

[0028] In one embodiment, the processor is configured to perform a baseline hearing assessment or measurement and store a corresponding user profile. The processor is programmed to obtain user feedback in response to generating each of twelve tones that are supplied through one or both of the drivers / speakers of the earcups. The user feedback or input may be provided using any of a variety of user interfaces, such as adjusting a slider or button in a mobile application until the tone is barely audible. After completion of the test, the recorded data represents the hearing threshold for that user. This data is compared to a previously stored equal-loudness curveto generate a delta assessment. The delta may be used to calculate digital filter coefficients to adjust subsequent performance of the noise cancellation and / or audio tuning to enhance speech intelligibility / recognition or any other type of particular sound or signal desired for enhanced detection. The assessment may be periodically performed to detect any measurable hearing loss.

[0029] Embodiments of the headgear with circumaural earcups may include a headset with a communication orboom microphone, headphones with speakers, and helmets.

[0030] In one or more aspects of the disclosure, an aviation helmet with integrated audio dosimetry includes a shell configured to extend over ears of a user and having an aperture, an earcup disposed within the shell, and a controller coupled to an electromechanical adjustment mechanism, such as a solenoid, connected to the earcup. Each earcup includes an internal microphone disposed therein and in communication with a controller or processor configured to store internal microphone measurements in an associated storage device or memory. One or more external microphones may also communicate with the processor. The external microphone(s) provide a signal in response to noise or sound detected outside of the earcups. The external microphone(s) may detect noise outside of the earcup but inside the helmet and / or outside of the helmet depending on the particular implementation. The processor may process noise exposure data and generate an alert in response to one or more characteristics of the noise exposure data. The alert may include a fitment alert that provides a visual, audio, or haptic indicator to the user to adjust fitment of the helmet and / or one or both earcups. Alternatively or in combination, the processor may control one or more electromechanical actuators to automatically adjust the fitment based on the dosimetry data.

[0031] Embodiments according to the disclosure may provide associated advantages. For example, one or more embodiments may be used to create a better internal cavity for acoustic quieting performance and wearability by correlating internal earcup noise with external earcup noise to improve fitment performance and reduce fatigue associated with side pressure. According to various aspects, personalized hearing loss compensation of the incoming audio signal may be used to dramatically improve speech intelligibility to the user. Measuring and analyzing signals from internal and external microphones to detect internal frequency and amplitude excursions within the acoustic cavity may facilitate real-time monitoring to identify dangerous feedbackconditions and control the active noise cancellation function. Those of ordinary skill in the art may recognize various other advantages based on the representative examples.

[0032] Implementations according to aspects of the present disclosure may have one or more associated advantages. For example, a helmet having integrated earcups with controllable electromechanical actuators according to this disclosure may provide improved ANR performance and comfort with automatic dynamic adjustments responsive to flight data measured by onboard sensors as compared to conventional aviation helmets or headsets. Controllable comfort cycling that periodically reduces side pressure may reduce wearer fatigue and improve mission effectiveness. Dynamic fitment adjustment of a helmet ANR. system according to one or more aspects uses closed loop feedback control of pressure actuators based on real-time, near real-time, and / or accumulated flight acoustic measurements to optimize side pressure and cup fitment for noise reduction, enhanced communication intelligibility, and better hearing protection throughout the mission to ensure more focused, capable, less-fatigued, and better-protected aviators. Dynamic fitment management based on automatic feedback control of side pressure may lower noise levels experienced by aviators to reduce mental fatigue while optimizing comfort for each phase of a mission. Proper fitment ensures optimal signal-to-noise ratio (SNR.) for all desired sounds, such as audio communications, to improve auditory awareness and clarity and speech intelligibility. Reduced pilot fatigue reduces mental workload while improving both auditory and visual attentiveness, provides better overall attenuation and easier communications clarity, improves comfort for those who otherwise have excess compression or side pressure on their cups, and facilitates wearability and comfort relief for long missions. Dynamic fitment may also improve hearing protection by ensuring safe levels of noise protection for both short-term and accumulated noise dosing. Strategic cycling of side pressure based on ambient noise levels may minimize incremental noise exposure due to a relaxed fit during comfort cycling. Active management of fitment, with improved noise attenuation, may reduce fatigue and improve overall mission effectiveness in demanding aviation applications.

[0033] The above advantages and other advantages and features will be readily apparent from the following detailed description when taken in connection with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIGURE 1 is a side view of an aviation helmet having integrated earcups with an electromechanical actuator connected to a controller to dynamically adjust fitment in response to feedback from one or more microphones according to various aspects of the disclosure.

[0035] FIGURE 2 is a top view of a representative electromechanical actuator of an aviation helmet for dynamic fitment adjustment of earcups within a helmet by a controller during use according to aspects of the disclosure.

[0036] FIGURE 3 is a partial cut-away top view of an aviation helmet with an electromechanical actuator coupled to a controller programmed to provide dynamic fitment adjustments of an earcup relative to a helmet shell with the earcup in a retracted position according to aspects of the disclosure.

[0037] FIGURE 4 is a partial cut-away top view of an aviation helmet having a controller coupled to an electromagnetic actuator operable to adjust or position an integrated earcup responsive to noise feedback or noise dosimetry according to aspects of the disclosure.

[0038] FIGURE 5 is a simplified control system block diagram used to determine various transfer functions associated with an adaptive ANR feature of an aviation helmet with dynamic fitment adjustment system or method.

[0039] FIGURE 6 is a flowchart illustrating operation of a system or method for dynamic fitment adjustment according to various aspects of the disclosure.

[0040] FIGURE 7 is a graph illustrating a relationship between circumaural earcup side pressure and sound attenuation.DETAILED DESCRIPTION[0041| As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary and may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural andfunctional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the teachings and representative embodiments of the disclosure.

[0042] For ease of description and illustration, this disclosure may use terms of relative motion that are intended to be interpreted broadly with respect to a helmet as normally worn on the head of a user. Alternatively, movement may be described along x, y, and z axes assigned according to an industry standard, such as SAE J211, for example. As such, terms such as inward and outward refer to movement toward or away from the head of the user, respectively, or along the y-axis. Similarly, inward and outward movements may be interpreted as movement within the helmet away from the helmet shell and toward the helmet shell, respectively. Other directional terms such as forward or rearward, or movement along the x-axis, may be used to describe directions toward the front or rear of the head of a user wearing the helmet. In a similar manner, upward and downward movements refer to movements along the z-axis toward the crown or chin, respectively.

[0043] Circumaural earcups deliver a level of noise attenuation as a primary function. The cup characteristics including shape, materials, thickness, and volume all contribute to the maximum theoretical or ideal attenuation of the system. The ear cushion / seal includes a flexible membrane attached to the opening of the earcup that provides a way to comfortably interface the cup system to a wearer’s head. The full 360-degree perimeter or circumference of the cushion / seal must contact the head to seal the space or cavity of the earcup to the head to provide any meaningful attenuation and noise isolation.

[0044] Due to the highly variable shape and contour of a 5%-95% human head, various sizes, thicknesses, and materials are employed to facilitate the desired 360-degree seal. The present inventors have recognized that varying amounts of side pressure is required to ensure the seal will compress and conform to the irregular surface contours of a given head to provide the desired seal. While the relative contours follow a narrower pattern of variability near the attachment of the ear to the head, the contour variability grows exponentially as the seal surface moves further from the base of the ear. The need for increased side pressure grows with a wider and / or longer seal line formed by a given ear seal shape. As such, user comfort is directly and significantly correlated with the ear seal circumference / perimeter design.

[0045] While ear seal circumference / perimeter design has a significant correlation with user comfort, changing flight operational conditions may affect ANR performance and user comfort relative to the static adjustments in an equipment room or even those made manually by an aviator during flight. As such, regardless of the particular ear cushion / seal design, various aspects of the present disclosure provide one or more processor-controlled actuators that couple the earcup to the helmet shell to controllab ly vary the side pressure of the ear cushion / seal in response to associated sensor signals to optimize ANR performance and comfort under various flight operational conditions. For example, internal and external noise data measured by corresponding microphones and stored in a memory may be processed by a controller having a programmed microprocessor to support ANR functionality, integrated noise dosing measurements, and monitoring of cup attenuation (ANR performance) relative to expected / known standards and thresholds. Internal cup noise data may be used to determine if any changes are needed to adjust one or more pressure points and control associated actuators to improve fitment. Side pressure may be increased to adjust cup fitment that does not provide adequate internal noise attenuation, or decreased to improve comfort if internal noise data / dosing is acceptable. External monitoring of mission noise may be used to further inform fitment adjustments. The feedback control of electromechanical or similar force pressure actuators that do not rely on an inflatable bladder by the controller / processor based on internal and external noise data (and / or other sensor data or user input) continuously informs the control of the pressure actuator(s) for each earcup to insure proper attenuation and comfortable fitment. A single actuator may be utilized to provide a side force to the earcup relative to the helmet with the force circumaurally distributed based on the characteristics of the ear seal / cushion. Alternatively, two or more actuators may be independently controlled to provide a distributed circumaural force in response to sensor input.

[0046] High-noise environments can significantly lower auditory and visual attention and increase flight fatigue. For military applications, average pilot noise exposure is 105dB + / - 5dB. It has been established that mental workload and visual / auditory attention is significantly reduced when participants are exposed to noise at 95 dBA level (P > 0.05). Furthermore, elevated ambient noise causes a deterioration of the signal -to-noise ratio (SNR) that directly impacts speech intelligibility. As such, the present inventors have recognized that with sustained mission noise levels for military applications in the 100-110 dB range, helmets need to prioritize isolation and quieting to reduce flight fatigue and reduce risk of hearing loss. Managing the earcup pressuresdynamically using automatic feedback control of one or more actuators based on at least sensed internal cup sound pressure / level according to embodiments of the present disclosure can maintain acceptable attenuation while providing both consistent pressure and occasional or periodic cup pressure relief to enhance comfort and reduce fatigue.

[0047] It is generally understood that anyone experiencing a high noise environment over time will unfortunately develop some level of permanent hearing damage or even disability. Over the past decade, the U.S. Department of Defense (DoD) began collecting hearing-related data from several branches of the military illustrating the detrimental impact these elevated noise levels are having on service personnel. The DoD Hearing Center of Excellence report for CY2019 showed that the U.S. Air Force had roughly 1 in 7 active-duty airmen who had either experienced a hearing impairment or a significant shift in useable hearing. It is likely this important data understates the actual damage of these high noise environments on service personnel due to the nature of the review sampling. The data acknowledged that participants were a mix of Airmen, Reservists and Civilians irrespective to their routine noise levels, thus inadvertently diluting the statistical data that would likely show the true impact on those in and around military high-noise environments. Pilots and supporting crew, working around military aircraft on a regular basis, may have a significant likelihood of developing a lifetime disability related to Noise-Induced Hearing Loss (NIHL)

[0048] One or more aspects of the present disclosure may provide a solution based on measuring full-spectrum in-helmet noise data using internal and external earcup microphones. Data associated with both noise levels and frequencies (dB and frequency content) may be captured, stored and analyzed in an integrated audio dosimeter within a circumaural earcup headgear system. Several software-based algorithms and analysis tools may be employed to gather and use full spectral data from both inside and outside helmets being worn by service personnel. This data may be used for monitoring exposure and triggering alerts related to sound exposure inside the earcup of an acoustic cavity to provide personalized and customized monitoring, performance, alerting, and dynamic control of fitment to improve effectiveness of hearing protection.

[0049] According to various aspects, customized Active Noise Reduction (ANR) is used in a variety of helmeted applications as well as other headgear. Utilizing elements of the existinghardware (HW) in place within the earcup systems of available ANR headgear enables collection of vital information for use in improving long-term aircrew hearing safety, while increasing overall mission effectiveness. This may beneficially reduce both mission stress and the long-term detrimental impact of the high noise levels experienced by those who are serving in the armed forces.

[0050] Damage to hearing occurs when noise levels are higher than 85 decibels, which is about the loudness of heavy traffic. The degree of loss depends on the loudness of the noise and how long one’s ears are exposed to it. Once hearing is damaged, it cannot be restored. The established U.S. OSHA regulations indicate that 8-hour exposures averaging over 85dBA are hazardous to worker hearing and lead to NIHL.

[0051] In noisy environments, all workers are required to wear some form of Hearing Protection Device (HPD). This could be either an In-The-Ear device like a foam ear plug or full muff-style, circumaural ear covering protection. To measure workers in a variable noise environment over an 8-hour shift, a portable device called a dosimeter is worn. This device collects environmental noise data. In high noise environments, the dosimeter utilizes a small microphone, positioned inside the protection device and close to the ear canal, to gather the level (frequency content and loudness) of noise that has reached the ear. An associated controller or processor then processes the collected data to determine a Time Weighed Average (TWA) of that exposure. This data is used to create a "Noise Dose”, or decibel number, for that worker over the time period worn.

[0052] This TWA exposure number is then compared to well established hearing damage data to determine if there is adequate protection for the wearer. For every 5dB of exposure above the 85dB threshold, the allowable ‘safe’ exposure time drops in half. That is, for an average exposure of 90 dB, the safe time limit is 4 hours, whereas an average exposure of 95 dB reduces the safe time to 50% or 2 hours. Recognizing the elevated / sustained noise levels in many / most of the aircrew mapped against extended mission times, there is a very high possibility of NIHL.

[0053] The accumulated costs associated with NIHL may be difficult to accurately assess, but likely include early retirement of trained personnel, disability compensation, and immeasurable loss of full quality of life for affected individuals. This may result from deteriorated hearingcapability, detected in annual testing, which ultimately affects mission effectiveness. This increases requirements for trained personnel to fill service needs with an attendant loss of experience and capability. Disability compensation is one cost, on top of ongoing use of the U.S. Veterans Administration (VA) system. This is often for life, to provide tools and equipment like hearing aids to allow basic functioning with a disability.

[0054] Various aspects of the present disclosure include an integrated noise dosing system for helmets that provides a means to measure the amount of noise exposure on a personalized basis for every airman, on every mission, every time. Identification and timely remedial actions may provide significant improvements to mission effectiveness and improved quality of life for a large subset of exposed service personnel.

[0055] In addition to military applications, headgear having integrated audio dosimetry features according to the present disclosure may have a meaningful impact in commercial / general aviation as well as commercial / industrial hearing protection applications. Many environments in these applications have consistently high (>90 dB) noise exposure levels and each have unique delivery needs that may be satisfied by one or more aspects of the present disclosure that combine various features of passive and active noise reduction with audio dosimetry and audio processing to enhance speech intelligibility / recognition or various other potential desirable sounds that meet specified characteristics, in addition to providing fitment alerts or automatic fitment adjustments based on the sound exposure data. User exposure to elevated noise creates both safety and operating effectiveness issues that may be reduced or eliminated by use of strategies and devices disclosed herein. Various aspects of the present disclosure provide a scalable hardware, software, and application strategy for a new class of communication products that may be referred to as “Safety Wearables”.

[0056] According to one or more aspects of the disclosure, a wearable device measures noise exposure at the ear and creates a personalized dosing record of noise inside a known acoustic environment and near the ear canal. Recognizing that user fitment is of primary concern, the exposure data can be used to provide specific / immediate alerts and automatic fitment adjustments in addition to recording the noise exposure history of a particular user. Correlation of noise measurements at the ear with those outside of the earcup(s) may be used to help identify whether noise exposure at the ear may be fitment-related and generate a corresponding alert or flag inresponse to prompt the user to adjust the fitment for implementations without automatic fitment adjustment capability. As previously noted, various helmet applications may automatically adjust the fitment in response to such an alert, or may adapt noise cancellation control accordingly.

[0057] Modern ANR systems are designed into acoustic cavities that deliver both passive and electronic (active) attenuation. The shape and volume of the internal cavity, along with the ear seal (the padded cushion that interfaces with the wearer) shape and construction, define the largest elements of both quieting and comfort of the system. Inside that cavity, there is a speaker delivering communication signals from the intercom, a microphone used for measuring internal noise profiles for ANR processing, and a connection to external audio sources (music, cell phone). Further, in digital systems, the microphone signals are digitized as part of the processing of the measurements.

[0058] Pilots and crew members may be required to wear a helmet with integrated communications to facilitate both mission effectiveness and hearing protection. With mission durations ranging from 4 to possibly 12 hours or more, the overall weight and fit of this wearable can impose both physical and acoustic compromises to the end user. Incorporation of acoustic systems according to one or more aspects of the disclosure may maintain or possibly improve communications intelligibility and noise exposure protection. The addition of an ANR cancellation system may improve both of those elements of mission effectiveness.

[0059] Proper fitment is a requirement to gain those quieting advantages and to ensure that aircrews are protected from the excessive noise levels of their aircraft operational environments. As discussed earlier, NIHL is a very real risk if both the helmets and ear cups do not fit properly and completely. Given mission lengths, end-user comfort of both items should be optimized where possible. Left unknown and uncorrected, airmen may begin to develop a significant or permanent shift / loss of hearing as supported by adequate anecdotal evidence in medical records of crew that have served for a number of years. Far too many airmen have had careers shortened due to a documented hearing loss.

[0060] Earcup shape and cavity research has resulted in embodiments of an earcup seal that creates more space for the ear pinna and lobe to improve fitment and wearability. Integrated into each ear cup, data may be gathered for every crew member for every flight / mission. This data may be used to alert both users, and their safety officer, of fitment issues that allowed an over-exposure to the ambient noises of the mission before accumulated exposure results in NIHL. Solutions could be quickly implemented to improve comfort / fitment while insuring adequate levels of protection.

[0061] According to various aspects of the disclosure, a programmed controller uses reference data and measures dynamic headset specific data to compare and adjust in compensation programming of the digital signal processor in the ANR control system. This applies directly to the dosing algorithms that may be utilized in various examples. The system may be used to define characteristics of the acoustics system under varying levels of sound pressure (SPLs) to create reference curves. These reference curves may form the basis of the detection by considering all variables of the acoustic systems, defined as Acoustic Response Correction Factor (ARCF) and their impact on sound pressure levels (SPLs) at the ear.

[0062] Hearing loss is a common problem that faces both pilots and non-pilots alike. Audio equalization allows audio delivery devices to deliver near hearing aid level of correction. While the concept of equalizing audio sources to enhance hearing is known, various aspects according to the disclosure assess the hearing threshold of the user and then correct the hearing loss in the headset without involvement of audiologists. The process to equalize the audio is like that used by audiologists to tune hearing aid devices. An assessment is made of how much loss there is at certain frequencies, then it is compared against a known reference. This generates a first approximation of the tuning for the user. After which a fine tuning is made according to the likes and dislikes of the user.

[0063] The hearing loss compensation process according to one or more aspects of the disclosure uses a larger number (twelve tones) rather than the eight singular frequencies commonly used to provide hearing loss information via audiologist testing. The user provides feedback on how much signal they hear by adjusting a slider or button in a mobile application until the tone is barely audible. After completion of the test, the recorded data is the hearing threshold for that user. This data is compared to an equal-loudness curve to generate a delta assessment. The delta is used to calculate digital filter coefficients to program into the device for adaptive processing as described in greater detail herein.

[0064] Understanding how the ear responds to and how the person judges the audio signals leads to providing better user experience in the cockpit and enhanced safety through clear communications. The testing and conversion profile are ascertained by a combination of pure signal tones, measurement, and user feedback. The user feedback closes the gap between what can be predicted about the sound at the user’s ear. Understanding this effect helps understand the noise presented at the ear of a user and begins to assess any acoustics error between the user’s ear and the speaker of the system.

[0065] The data gathered during validation indicated both a measurable assessment of any hearing loss that may be present and improvement of the audio quality as perceived by the user. Outside of the controlled laboratory environment, pilots have reported an improvement in the hearing experience, with the most dramatic reactions reported by those with moderate to severe hearing loss. In this group, music sounded richer and fuller and speech intelligibility was noted to improve. Those with minor or no hearing loss noted an improvement in the richness and fullness of the audio presented but did not report any significant improvement in speech recognition.

[0066] Various aspects according to the disclosure may also provide instability detection, which may be important and necessary to protect hearing and focus on the mission. The system may measure the response of dynamically changing data across the entirety of the frequency spectrum. By successfully monitoring from 8Hz to 22kHz, the system can measure, analyze, and act on the full spectrum of the auditory range to assess and report total daily user exposure.

[0067] Active Noise Reduction systems use microphone(s) for measurement of sound pressure and convert it to an electrical signal for processing. The internal microphones are used to measure the noise internal to the ear cup for feedback processing and external microphones measure the noise external to the ear cup for feedforward processing when the technology implements hybrid ANR. The feedback subsystem is a closed loop control system that may be susceptible to runaway amplification (progressive uncontrolled volume increase) if not carefully controlled. Even with careful design of systems, there may still be occurrences in extreme environments of runaway amplification (instability). In these situations, the system will become unstable across the audible and inaudible ranges of frequencies. If not detected and controlled by the system, pilots with ANR enabled helmets can have >120dB SPL at their ear requiring manual intervention and loss of situational awareness.

[0068] In high performance ANR systems, the designers must take infrasound and ultrasonic stability into account. Infrasound instability can lead to under-damped ANR. with clipping and rhythmic low frequency instability events. Higher frequency and ultrasonic instability can lead to instability events that are typically described as “squealing”. Methods aimed at detecting and potentially controlling the instability events must inherently measure across the infrasound to ultrasound range. However, system limitations may limit the total range of infrasound that can effectively be measured.

[0069] The instability detection methodology according to various aspects of the disclosure measures the characterized system acoustics in conjunction with microphone-based measurements to assess if the closed loop ANR system is unstable at any frequency from subsonic to ultrasonic ranges. This method is also capable of measuring, detecting, and rejecting secondary audio sources that may cause an auditory response in the system similar to a feedback event, but are meant for audio warnings or alerts to the user. After detection of an instability event, the system acts through preprogrammed means from complete power off to a failsafe communication state or manipulation of the ANR system to control the feedback event while still providing communication and a reduced level of ANR.

[0070] The algorithm uses an approach based on establishing baseline characteristics of the acoustic system to form a cluster of data based inclusive of the mean and covariance of the analyzed system. By assessing all other noises as a secondary cluster of data, the system can detect if the noise is part of normal operation (ANC, communication, external audio, feed-through microphones) or an instability event. After detection of the instability event the system can turn off the ANC or determine what signal processing filter can be altered to control the instability. In the event of an instability detection, the system can turn off the ANC function in an average of 0.9 seconds across a range from 8Hz to 22kHz.

[0071] As previously described, helmets are worn to protect the head of the user from injuries that may occur in a wide variety of recreational, occupational, transportation, and military applications. The helmet design may vary depending on the type and frequency of expected impacts. Similarly, use patterns may vary from repeated removal of the helmet between short duration uses, such as those that may occur in football or hockey, to extended periods of use, such as those that may occur in occupational, transportation, or military applications, for example. Inmany applications, the helmet may extend partially or completely over the ears of the user. The helmet may be designed to reduce transmission of external sound, or to minimally impact transmission of external sound to the wearer. Active audio devices such as speakers and microphones and / or passive devices such as acoustic sound absorbing material may be used alone or in combination to provide the desired helmet acoustics.

[0072] In passive and active noise reduction helmet applications, performance and wearability may be improved by providing a complete seal around or within the ears without compromising comfort overlong use durations. The present inventors have recognized that current helmet designs appear to lack the ability to achieve these seal and comfort goals without significant tradeoffs between them.

[0073] A variety of non-military helmets and others that do not include fully customized shells provide adjustable ear cups. However, the ear cup assembly is mounted and positioned within the helmet using a repositionable or removable fastener, such as a hook and loop closure. The external shell is a hard molded shape with the ear cup assembly moveable within the inner lining of the shell. Foam pads and strips of hook and loop closure material is used to provide a customized fit for each user. These types of positioning systems require that the helmet be removed to position the ear cup assembly and comfortable positioning often requires several trial and error attempts by the user. These systems are also generally fixed or static once positioned within the helmet, although repeatedly wearing and removing the helmet may disturb the positioning of the ear cups. In addition, side pressure is established by the external shell dimension and the selection or combination of padding positioned through this iterative process. These systems are generally not amenable to additional adjustments during use with respect to position or pressure and may experience reduced performance with respect to comfort and seal over a particular period of use.

[0074] Helmets having active noise reduction (ANR) technology to cancel at least some of the unwanted external noise rely on a good seal around or in each ear to achieve best results. A good seal is particularly difficult to achieve inside a helmet for at least two reasons: helmets generally fit tightly to provide their protective function, and the ear pinna protrudes from the surrounding surfaces of the head and varies in shapes and sizes among users. As such, putting the helmet on and proper positioning of previously placed ear cups or earphones can be very challenging. After the helmet is placed on the head, the seal around the ear may not be ideal basedon ear position (within the ear cup) or the ear cup position relative to the skull, and the fitment may change based on movements during use. To achieve desired acoustic performance, users may over-compensate for acoustic leak paths by increasing the side pressure, which may result in reduced comfort particularly over long periods of time.

[0075] For best performance of an ANR system, the positioning of the ear canal and pinna relative to the driver / speaker and ANR feedback microphone within the ear cup or earphones should be understood and repeatable. Current solutions generally fail to deliver consistent performance with either the acoustics or the cushion / seal system. Available helmet shell-based solutions also generally do not offer customized left cup and right cup acoustic systems that are used by the best performing non-helmet based ANR headsets. Largely due to positioning and comfort constraints previously described, existing helmets use a full round / oval seal that does not leverage various advantages associated with a “slot seal” design that allows the pinna to extend into a slot between the cushion and other components of the ear cup, which may provide a better seal for a given amount of side pressure. This is likely because of the difficulty in positioning the pinna into the ear slot seal when donning the helmet due to the fixed ear cup within the helmet.

[0076] Referring now to Figures 1 and 2, Figure 1 is a side view of a helmet having integrated earcups with an electromechanical actuator in communication with a programmed processor or controller to provide dynamic fitment adjustment or positioning of the earcups based on feedback signals from one or more sensors, such as internal microphone and external microphones. Figure 2 is a top view of a representative example of a controllable electromechanical adjustment mechanism for positioning earcups within a helmet during use to provide dynamic fitment adjustments.

[0077] Helmet 100 includes a shell 110 configured to receive and substantially surround integrated circumaural earcups 112, only one of which is illustrated in the Figures. Typical applications include an earcup 112 for each of the ears 114 of a user 116. Each of the earcups 112 may be substantially identical for left and right ears, or may be customized with different earcups for the right and left ears 114. Similarly, earcups 112 may be customized for a particular user with the left and right earcups for that user being the substantially identical. In some embodiments, the left and right earcups 112 may include different components for passive and / or active noise reduction or audio, sound equalization, stability control, etc. as described herein. For example, inpassive noise reduction applications, only one of the earcups 112 may include a speaker to provide mono audio. Typical active noise reduction (ANR) applications include a driver / speaker and at least one noise-sensing or error sense microphone 127 positioned within each of the earcups 112 to provide active noise reduction and stereo audio for user 116. An ambient microphone 129 may be associated with each of the earcups 112 to provide signals corresponding to ambient SPLs outside of the earcups 112 and / or external to the helmet 100. Helmet 100 may also include an integrated communication microphone (not shown), such as a boom microphone, to capture voice input from user 116.

[0078] As those of ordinary skill in the art will appreciate, although the representative embodiments include circumaural earcups 112, the teachings of the present disclosure may be equally applied or adapted to other types of acoustic headphones or earphones including supraaural headphones and in-the-ear type headphones, earphones, earbuds, etc. although other types of headphones and earphones may not achieve various advantages associated with improved sealing and comfort.

[0079] As also shown in Figure 1, helmet 100 includes an electromechanical adjustment mechanism or actuator 120 associated with each of the earcups 112, which may have a portion 230 (Figure 2) adapted to couple to an associated earcup and a portion 130 extending through an aperture or elongated slot 140 in the shell 110 to move the associated earcup 114 between a retracted position and an engaged position (best illustrated in Figures 3 and 4) using portion 130 extending through shell 110, and to position or move the earcups 112 toward or away from shell 110 to adjust side pressure and provide dynamic fitment adjustment. Elongated slot 140 may be positioned at an angle relative to a bottom edge 144 of helmet 100, or alternatively relative to the x-axis to provide movement of earcups 112.

[0080] As described in greater detail with reference to Figures 2-5, portion 130, which optionally extends through shell 110 may be used to selectively clamp against the electromechanical actuator or adjustment mechanism 120 may include a solenoid or similar motor 123 coupled to portion 130 to position earcups 112 as described herein. The solenoid is electrically coupled to one or more associated programmed controllers or processors 125 to provide dynamic fitment adjustment responsive to signals from the microphone(s) as described in greater detail herein. The solenoid or similar controllable motor or device may also be controlled to secure theactuator 120 at a desired position within elongated slot 140 of shell 110 in applications that provide additional earcup positioning for donning and doffing the helmet 100. In addition, external portion 130 of actuator 120 may be used to control distance between the associated earcup 112 and the interior of shell 110 to increase or decrease resulting side pressure of the earcup experienced by user 116 during helmet use in response to the feedback signals provided by the microphone(s).

[0081] As illustrated in Figure 1, helmet 100 includes a shell 110 configured to cover ears 114 of user 116. In various embodiments, helmet shell 110 substantially or entirely covers earcups 112 when viewed from the side or along the y-axis. While the front portions of earcups 112 may be visible from the front and bottom of helmet shell 110, each of the earcups 112 is contained substantially within shell 110. As described in greater detail with reference to Figures 2-5, earcups 112 are integrated within shell 110 and may be externally positioned using actuator 120 while helmet 100 is in use or worn by user 116. As will also be appreciated by those of ordinary skill in the art, actuator 120 may be entirely contained within helmet shell 110.

[0082] In one embodiment, earcups 112 each include an ear seal or cushion 118. Actuator 120 facilitates positioning of earcups 112 after user 116 dons helmet 100. Position of earcups 112 while helmet 100 is worn by user 116 facilitates alignment of each pinna 122 of an associated ear 114 with an associated slot or gap between cushion 118 and earcup housing 220 (Figure 2) as earcups 112 are moved between a retracted position (Figure 3) and deployed or engaged position (Figure 4).

[0083] As shown in the top view of Figure 2, a representative actuator 120 facilitates positioning of earcups 112 within helmet 100 during use. Actuator 120 includes an arch 232 adapted to be fixedly secured to an interior portion of shell 110 (Figure 1). In the embodiment illustrated, arch 232 is implemented by a generally three-sided or four-sided rectangular or a curved or arcuate component having a bottom side or the bottom portion adapted to be secured within an interior portion of the helmet shell. Bridge or arch 232 includes an opening adapted or configured to receive positioning component or positioner 240.

[0084] Positioner 240 includes a first arm 242 and a second arm 244 connected at a proximate end 250 and spaced apart from one another at a distal end. Each arm 242, 244 includes an aperture adapted to receive an earcup mounting post 260. Earcup housing 220 is secured toearcup mounting post 260 using fasteners 262. Alternatively, post 260 may be secured to housing 220 using an adhesive, or may be integrally formed with housing 220, for example. Mounting post 260 may include internal and / or external threads to cooperate with a threaded stud 270 associated with portion 130 to adjust distance between earcups 112 and the helmet shell, resulting in varying side pressure of the earcups 112 for the user. Threaded stud 270 may be coupled to or integrated with an electric motor driven interface 272. Actuation of the motor (or alternatively a linear actuator such as a solenoid 123) by controller 125 may be used to adjust distance between the interior of the helmet shell and earcups 112 by engaging complementary threads between post 260 and stud 270. Side pressure may be adjusted during use of the helmet to facilitate improved sealing between the user’s head and cushion 118 of earcup 112, as well as to improve user comfort as described herein.

[0085] Arms 242 and 244 of positioner 240 may be resiliency biased relative to one another. In one embodiment, a spring (not shown) is operatively associated with arms 242, 244 to resiliently bias arms 242, 244 away from each other. The spring may be a linear spring positioned between arms 242, 244 or a coil spring associated with a hinge 274 connect first arm 242 to second arm 244. Alternatively, arms 242, 244 may be formed of a resilient material, such as a plastic or spring steel to bias arms 242, 244 away from one another. In one embodiment, a single arm 244 is resiliently biased away from an interior portion of shell 110.

[0086] In one embodiment, actuator 120 may include a clamping device operatively associated with positioner 240 and having a portion 130 extending through the elongated slot 140 of shell 110 to move positioner 240 within the opening of arch 232 and to selectively secure positioner 240 in a user selected position along the elongated slot 140 of shell 110. Figure 2 illustrates three representative positions in broken lines representing positioner 240 as it moves within the opening of arch 232 including a retracted position, and two deployed / engaged positions. While three representative positions are shown, actuator 120 is generally continually adjustable along the length of elongated slot 140. In other implementations actuator 120 is contained within helmet shell 110 and can be moved by an additional slidable adjustment mechanism similar to that shown with respect to Figures 1-5.

[0087] As generally illustrated in Figures 1 and 2, actuator 120 may be operated via motor interface 272 and connected controller to position earcup 112 for a selected or desired seal andcomfort while wearing helmet 100. As positioner 240 moves within the opening of a lateral positioning component, implemented by arch 232 in the representative example illustrated, arch 232 forces second arm 244 toward first arm 242 to provide lateral movement of earcup 112. Second arm 244 may include one or more portions angled relative to one another to facilitate movement within arch 232 and / or to provide a desired movement trajectory or profile of earcup 112 between retracted and engaged positions.[0088| Referring now to Figures 3 and 4, Figure 3 is a partial cut-away top view of a representative example of a helmet having an electromechanical actuator for dynamic fitment adjustment with at least a portion of the actuator extending through an aperture of the helmet shell. The earcup is in a retracted position. Figure 4 is a partial cut-away top view of a helmet having an electromechanical actuator for dynamic fitment adjustment with at least a portion of the actuator extending through an aperture of the helmet shell. The earcup is in a deployed or engaged position. Figures 3 and 4 include components similar or identical to the previously described examples with some alternative features incorporated as illustrated and described. Primed reference numerals are used to denote features that provide similar functions as previously described, but that may have an alternative implementation or details relative to the previously described feature or component. In the embodiments of Figures 3 and 4, alternative implementations of an electromechanical actuator 120’ and 120” are illustrated.

[0089] As generally illustrated in Figure 3, actuator 120’ includes a base 290 fixed to an interior portion 294 of shell 110 and having a surface profile 296 configured to guide the positioner 240’ along a desired trajectory or profile as positioner 240’, portion 270, motor interface 272, and motor 123’ moves within the elongated slot of shell 110. Positioner 240’ includes arms 242’, 244’ formed of a single, unitary U-shaped component rather than a hinged component. Positioner 240’ may be formed of a resilient material, or may cooperate with one or more springs to provide a biasing force between arms 242’ and 244’ . In the examples illustrated in Figures 3 and 4 a threaded stud 270 extends through the elongated slot with a motor interface or adapter 272 secured thereto. Adapter 272 has a diameter larger than a width of the elongated slot and is rotatable by rotary action of motor 120’ responsive to a controller signal. A threaded receiver 292 is secured to positioner 240’ and configured to cooperate with the threaded stud 270 and adapter 272.

[0090] The embodiment of Figure 4 includes an adjustment mechanism 120” that includes a positioner 240 in combination with base 290. Adapter 272 is connected to a threaded stud to engage complementary threads of receiver 292 to move earcup 112 toward or away from helmet shell 110 as previously described. The portion of the actuator 120” implemented by threaded stud adapter 272 and receiver 292 includes a pair of nested threaded posts including a first post coupled to the earcup 112 to adjust distance between the earcup 112 and the interior 294 of shell 110 to adjust side pressure based on actuation of motor 123”. A second post cooperates with receiver 292 or a locking nut to selectively clamp the actuator 120” to shell 110 as previously described.

[0091] As generally illustrated in Figures 3 and 4, actuators 120’, 120” may include a portion extending through the helmet shell and engaging a motor or solenoid coupled to a controller to provide dynamic fitment adjustment. User input from a switch, button, or coupled wireless device requesting manual fitment adjustment may also be processed by the controller to operate the actuator in some implementations as described herein. Actuators 120’, 120” are configured to simultaneously move the earcup 112 inward and forward between a retracted position illustrated in Figure 3, and a deployed or engaged position illustrated in Figure 4. Prior to removing the helmet, the actuators 120’, 120” may be externally operated to simultaneously move the earcup 112 outward and rearward using the portion extending through the shell during use of the helmet.

[0092] Figure 5 is a simplified control system block diagram and supporting equations used to determine various transfer functions associated with an adaptive ANR system or method features of a helmet having dynamic fitment adjustment. The control system block diagram of Figure 5 may be used to derive a target feed forward response (HB) that would provide total noise cancellation in an idealized system. The block diagram of Figure 5 includes an input for a signal from an ambient noise microphone, although those of ordinary skill in the art will recognize that the same principles may be applied to systems that do not include an ambient noise microphone or associated signal.

[0093] In the method and system for ANR of Figure 5, an adaptive realizable filter is used, specifically, an UR filter rather than a FIR filter, with the end result that the performance measured as attenuation vs frequency is totally independent of the statistics of the noise, (i.e. periodic methods don't work well if the noise is not periodic.)

[0094] As shown in Figure 5, the internal sense microphone signal M 302 is multiplied by a linear factor Ki at 304 and combined at block 306 with the communication (comm) signal 308. The combined signal is processed by the target response HA at block 310 and combined at block 312 with the processed signal associated with the noise signal N represented at 320. Noise signal N is multiplied by a constant K2 as indicated at 322 and the target feed forward response HB at block 324 before being combined as described above at block 312. Noise signal N at 320 is multiplied by Tp at block 326 with the result provided to block 334. The output of block 312 is multiplied by e He at 330 and Tdm at 332 before being combined at 334 with the output from block 326 to generate output M at 336, which represents the error or sense microphone signal used in the feedback loop. Block 332 represents the response or transfer function between the driver D at 340 and the sense microphone M at 336.[0095| Those of ordinary skill in the art will recognize that measuring the driver / speaker to error or sense microphone response between the driver / speaker 46 and sense microphone 48 represented by Tdm in use is ideal, and can be done actively or passively. For active measurement of Tdm, a test signal is used as the stimulus. This can be any signal that excites the modes of the system. For example, a multitone, chirp, log chirp, or random noise are some examples of a possible test signal or active stimulus. A test signal that is periodic about a value n, where n represents the FFT size eliminates the need for a window function. Of course, an FFT is just one basis and the representative methods illustrated will work independently of the basis chosen for solving the problem. Other adaptive strategies that minimize the error by a gradient search may also be used, such as a least mean squares (LMS) or root mean squares (RMS) optimization, for example.

[0096] The response or transfer function Tdm of block 332 can also be measured passively, but using normally occurring signals such as the speech or aircraft noise. If only aircraft noise is used, the system closed loop response can be perturbed to allow the simultaneous estimation of both Tdm and Tp. Otherwise, there is only one equation and two unknowns. To provide a solution, for the two unknowns requires another equation, i.e. the system is perturbed (the loop gain of the closed loop filters is changed slightly so that two equations are created. During the process the system performance is perturbed for the purpose of determining the two parameters related to the driver to mic response (Tdm) and the noise to mic response (Tp) unknowns.

[0097] The control equations may be derived from the block diagram in Figure 5 where:M represents the sense / error microphone;N represents the ambient noise measured by the ambient microphone;Tprepresents passive attenuation corresponding to M / N with no active or comm signal present;Tnam represents active attenuation at the sense microphone corresponding to measured M / N with no comm signal present; andTdm represents the driver to error mic response.

[0098] The system design allows for the sense / error microphone 48 to be placed much closer to the ear opening than previous implementations. This has the key advantage of being a more accurate estimate of what the user actually hears, i.e. there will be smaller differences in Tdm and Tde, and in T nm and T lie-

[0099] The system uses a feedforward method that includes a feedback loop. For closed loop feedback operation, the signal from the error microphone M is fed back into the system to reduce noise as generally represented in Figure 5 with output 336 and input 302. In the feedforward mode, the error microphone, which is positioned as close as possible to the ear opening and much closer than in conventional ANR applications, more accurately represents audio heard by the user. This signal is used to monitor performance and continuously update the transfer function of the feedforward filter HB as shown in the block diagram.

[0100] As generally used herein, a programmed controller or processor may be implemented as a dedicated controller or may cooperate with one or more other controllers to perform various functions described in the text and illustrated in the drawings. Control logic, functions, code, software, strategy etc. performed by one or more processors or controllers 125 may be represented by block diagrams or flow charts. The representative control strategy, algorithm, and / or logic for operation of a system or method for dynamic fitment adjustment, ANR, equalization, etc. described according to one or more aspects of the disclosure may be implemented using one or more processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various steps or functions illustrated or described may be performed in the sequence as illustrated or described, in parallel, or in some cases omitted. Although not always explicitly illustrated or described, one of ordinary skill in the art willrecognize that one or more of the steps or functions may be repeatedly performed depending upon the particular processing strategy being used. Similarly, the order of processing is not necessarily required to achieve the features and advantages described herein, but is provided for ease of illustration and description. The control logic may be implemented primarily in software executed by one or more microprocessor-based controllers or control modules that may communicate with one another and distribute various control tasks or functions depending upon the particular application and implementation. When implemented in software, the control logic may be provided in one or more non-transitory computer-readable storage devices, media, or memory having stored data representing code or instructions executed by the controller or processor to provide the described functions. The storage devices may include various working variables, parameters, SPL thresholds, dosimetry data or thresholds, or other data, such as a lookup table used to control dynamic fitment adjustments, ANR, equalization, hearing compensation, etc. as described herein.

[0101] Figure 6 is a flowchart illustrating operation of a system or method for dynamic fitment adjustment of circumaural earcups in a helmet according to various aspects of the disclosure. System or method 600 may be implemented by one or more programmed microprocessors or controllers as previously described. The system or method monitor microphone signals from one or more microphones, which may include an internal microphone and an external microphone associated with each of the earcups in the helmet as represented at 610. The internal microphone or sense microphone is positioned within the earcup and may be used to provide ANR functionality as previously described in addition to being used for dynamic fitment adjustments. The external or ambient microphone is positioned to monitor ambient sound pressure levels outside the earcup and / or outside the helmet depending on the particular implementation. The external or ambient microphone may also be used to provide feedforward ANR control in addition to dynamic fitment control. Signals from the microphones are sampled, stored, and processed to determine various sound pressure level (SPL) statistics as represented at 612. SPL statistics may include peak, average, standard deviation, time duration above one or more corresponding SPL thresholds, etc. for use in subsequent dynamic fitment control. Noise or sound dosimetry analysis may be performed by the controller and represented by one or more dosimetry metrics or parameter values.

[0102] Internal microphone SPL is compared to a corresponding threshold as represented at 614. The corresponding threshold may be one of a plurality of previously stored thresholds retrieved from memory based on a current mission, current user, or current operating conditions, for example. For example, users with higher noise dosing or some hearing loss may have a lower threshold selected to prevent further hearing loss. If the internal microphone SPL exceeds the threshold at 614, the actuator is controlled to increase side pressure by increasing distance between the earcup and the helmet shell as represented at 626. The actuator may be controlled to provide an incremental increase with the algorithm or process then returning to block 610. Alternatively, the actuator may be continuously controlled to increase side pressure until the internal microphone SPL is below the corresponding threshold.

[0103] If the internal microphone SPL is below the threshold at 614, then block 616 determines whether one or more noise dosimetry parameters are above an associated threshold. If yes, then block 626 controls the actuator to increase side pressure as previously described. If no at block 616, then block 618 determines whether a periodic timer has expired. If the periodic timer has expired, then block 620 determines if the external microphone SPL is above a corresponding threshold (which is greater than the SPL threshold for the internal microphone). If no, then block 622 controls the actuator to reduce or decrease the side pressure by moving the earcup toward the helmet shell. The periodic timer may be used to reduce side pressure to increase comfort and reduce fatigue of the wearer. However, periodic comfort cycling may be suspended if the ambient microphone detects SPLs exceeding a corresponding threshold at block 620. The amount of decrease for the side pressure may vary based on the SPL detected by the external microphone. For example, a larger decrease of side pressure may be allowed where the external microphone detected SPL is below a first corresponding threshold with a smaller decrease in side pressure allowed where the detected SPL is above the first threshold but below a second threshold.

[0104] Block 624 represents a user request to adjust fitment. The user request may be received by the controller via a physical switch such as a button or slider, or via a software control on the helmet, a control box, instrument panel, or a wirelessly connected device such as a smartphone app. A user request to reduce side pressure may be limited or delayed based on the SPL detected by the external microphone exceeding a corresponding threshold as indicated at 620. The corresponding threshold may be unique to user requests and different from thresholds appliedto automatic control. If the detected SPL is below the threshold, block 622 controls the actuator to provide a manual or user adjustment to decrease side pressure. Individual control for each earcup may be provided depending on the particular implementation. In a similar manner, user input requesting an increase in side pressure received at 624 may be used to control the actuator to increase side pressure as indicated at 626.

[0105] Figure 7 is a graph illustrating a relationship between circumaural earcup side pressure and sound attenuation as determined from empirical data from prototype testing in a controlled environment. As generally indicated by the graph of Figure 7, increasing side pressure reduces leak paths and provides higher noise attenuation as measured inside the earcup. The data provided by such testing may be used to establish limits for increasing or decreasing earcup side pressure for dynamic fitment control.

[0106] As demonstrated by various examples described herein, a helmet having integrated earcups associated with an electromechanical actuator to provide dynamic fitment adjustment facilities in-use adjustments to improve earcup seal and comfort while being worn by the user. Positionable earcups that move between a retracted position and deployed position facilitate donning and doffing the helmet and reduce or eliminate trial and error adjustments that require helmet removal.

[0107] As those of ordinary skill in the art will appreciate, the enclosed description and supporting Figures and graphics of aviation headsets and helmet systems having passive and active noise reduction / cancellation and communications capabilities provide supporting details for various subsystems, components, algorithms, etc. that may be combined in an automatic dynamic fitment adjustment system with actuators controlled by a controller responsive to signals from one or more audio / sound sensors as described above.

[0108] While the best mode has been described in detail, those familiar with the art will recognize various alternative designs and embodiments within the scope of the following claims. While various embodiments may have been described as providing advantages or being preferred over other embodiments with respect to one or more desired characteristics, as one skilled in the art is aware, one or more characteristics may be compromised to achieve desired system attributes, which depend on the specific application and implementation. These attributes include, but are notlimited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. The embodiments discussed herein that are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.

Claims

WHAT IS CLAIMED IS:

1. An aviation helmet, comprising:a shell configured to extend over ears of a user;circumaural earcups disposed within the shell, each of the earcups having an ear seal, an error sense microphone, an ambient microphone, and a speaker;at least one electromechanical actuator associated with each of the earcups, the actuator configured to move at least a portion of an associated earcup relative to the shell; and at least one controller in communication with the error sense microphones, the ambient microphones, the speakers, and the at least one electromechanical actuator, the at least one controller programmed to control the at least one electromechanical actuator in response to signals from one or more of the error sense microphones and the ambient microphones.

2. The aviation helmet of claim 1 wherein the at least one controller is programmed to control the at least one electromechanical actuator to increase distance between at least a portion of the associated earcup and the shell in response to signals from at least one of an associated error sense microphone and an associated ambient microphone that correspond to increasing sound pressure level (SPL).

3. The aviation helmet of claim 2 wherein the at least one controller is programmed to process signals from the error sense microphones and the ambient microphones to generate signals for the speakers that provide active noise reduction.

4. The aviation helmet of claim 3 wherein the at least one controller is programmed to control the at least one electromechanical actuator to periodically decrease distance between at least a portion of the associated earcup and the shell for a predetermined time period.

5. The aviation helmet of claim 4 wherein the at least one controller is programmed to suspend periodically decreasing the distance while sound pressure level (SPL) detected by at least one of the error sense microphones and the ambient microphones exceeds a corresponding SPL threshold.

6. The aviation helmet of claim 3 wherein the at least one controller is programmed to control the at least one electromechanical actuator to decrease distance between at least a portion of the associated earcup and the shell until signals from the associated error sense microphone indicate sound pressure level exceeding a previously stored SPL threshold.

7. The aviation helmet of claim 1 wherein the at least one controller is programmed to control the at least one electromechanical actuator to decrease distance between at least a portion of the associated earcup and the shell in response to signals from at least one of an associated error sense microphone and an associated ambient microphone that correspond to sound pressure level (SPL) being below a previously stored SPL threshold.

8. The aviation helmet of claim 1 wherein at least one of the ambient microphones is positioned to detect ambient sound external to the helmet.

9. The aviation helmet of claim 1 wherein the at least one controller is configured to receive voice communication signals, the at least one controller further programmed to control the at least one electromechanical actuator to move at least a portion of the earcups to increase distance between the earcups and the shell in response to receiving voice communication signals.

10. The aviation helmet of claim 1 further comprising a user input configured to receive requests for earcup pressure adjustments, wherein the at least one controller is further programmed to control the at least one electromechanical actuator in response to the user input.

11. The aviation helmet of claim 10 further comprising a communication microphone coupled to the at least one controller, wherein the user input comprises the communication microphone.

12. The aviation helmet of claim 10 wherein the at least one controller is further programmed to limit earcup pressure adjustments requested via the user input that decrease distance between the earcups and the shell in response to signals from at least one of the error sense microphones and the ambient microphones indicating sound pressure level exceeding a corresponding SPL threshold.

13. The aviation helmet of claim 1 wherein the at least one electromechanical actuator comprises:a base fixed to an interior of the shell and a portion extending through an aperture of the shell to facilitate movement of the earcup using the portion extending through the shell; and a solenoid connected to the portion extending through the aperture, the solenoid coupled to the at least one controller.

14. The aviation helmet of claim 13 wherein the solenoid is controlled by the at least one controller to move an associated earcup toward and away from the shell using the portion extending through the shell to adjust side pressure of the earcup during use of the helmet.

15. The aviation helmet of claim 14 wherein the at least one controller controls the solenoid to move the associated earcup away from the shell to increase side pressure of the earcup during use of the helmet based on signals from at least one of the error sense microphones and the ambient microphones indicating sound pressure level (SPL) exceeding an associated SPL threshold.

16. A method for adjusting fitment of ear seals of circumaural earcups within an aviation helmet, the method comprising, by a programmed controller:controlling at least one electromechanical actuator to move the earcups toward or away from a shell of the aviation helmet to adjust side pressure of the earcups and ear seals on the head of a wearer in response to feedback signals from at least one microphone.

17. The method of claim 16 wherein controlling the at least one actuator comprises controlling the at least one actuator to move the earcups away from the shell in response to the at least one microphone detecting sound pressure level (SPL) exceeding a corresponding threshold.

18. The method of claim 17 wherein the at least one microphone comprises an error sense microphone positioned within each of the earcups.

19. The method of claim 17 wherein the at least one microphone comprises at least one ambient microphone positioned to detect sound outside of the earcups.

20. The method of claim 16 wherein controlling the at least one actuator comprises controlling the at least one actuator to periodically move the earcups toward the shell to reduce side pressure.

21. The method of claim 20 wherein the at least one actuator is controlled to periodically move the earcups toward the shell to reduce side pressure for a programmable period of time.

22. The method of claim 20 wherein the at least one actuator is controlled to periodically move the earcups toward the shell to reduce side pressure until the at least one microphone detects sound pressure level inside the earcup exceeding a corresponding threshold.

23. The method of claim 20 further comprising:suspending periodically moving the earcups toward the shell in response to the at least one microphone detecting sound pressure level inside the earcup exceeding a corresponding threshold; andresuming periodically moving the earcups toward the shell in response to the at least one microphone detecting sound pressure level inside the earcup being equal to or below the corresponding threshold.

24. The method of claim 16 wherein the at least one microphone comprises: an error sense microphone positioned within each of the earcups; and an ambient microphone associated with each of the earcups and positioned to detect sound outside of the earcups.

25. The method of claim 24 further comprising, by the programmed controller, processing signals from the error sense microphones and the ambient sense microphones and generating active noise reduction (ANR) signals communicated to a speaker within each of the earcups.

26. An aviation helmet comprising:a shell configured to extend over ears of a user;a pair of earcups disposed within the shell;an ear cushion connected to each earcup;an error sense microphone positioned in each of the earcups;one or more electromechanical actuators coupling each earcup to the shell; and a controller in communication with the one or more electromechanical actuators and programmed to control the actuators to adjust position of the earcups relative to the shell and associated side pressure acting on the head of a wearer by an associated ear cushion responsive to signals from at least the error sense microphones positioned in the earcups.

27. The aviation helmet of claim 26 further comprising a speaker / driver positioned within each of the earcups, wherein the controller is programmed to process signals from the error sense microphones to generate active noise reduction signals provided to the speaker / driver positioned within each of the earcups.

28. The aviation helmet of claim 27 further comprising an ambient microphone associated with each of the earcups, wherein the controller is programmed to process signals from the ambient microphones to generate active noise reduction signals provided to the speaker / driver positioned within each of the earcups.

29. The aviation helmet of claim 28 wherein the controller is programmed to control the electromechanical actuators to increase the side pressure responsive to sound pressure level detected by at least the error sense microphones exceeding an associated threshold.

30. The aviation helmet of claim 28 further wherein the controller is programmed to control the electromechanical actuators to increase the side pressure responsive to sound pressure level detected by the ambient microphones exceeding an associated threshold.

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