Patent Application
20090243842
The field of the invention relates generally to maintaining search and inspection requirements for operation of individual aircraft, and more specifically, to methods and systems for sensing activity using energy harvesting devices.
Many airline procedures are in place to ensure the safety of passengers, crew and equipment. In one instance, a visual inspection process of an airline interior, for example, may include visually looking for opened doors, visually looking for broken tamper evident tapes, and/or manually opening the various doors, panels, and covers generally found within a passenger airliner cabin. The process is conducted to visually inspect the spaces, or volumes, behind these devices, whether or not the doors, panels, and covers have been accessed.
Visually inspecting these spaces and volumes is labor intensive and the process results in an incurred expense for the airline operator. The process may also result in an extended airport gate turn around time. The reality, however, is the vast majority of these spaces have not been accessed or otherwise tampered with. Therefore, the vast majority of visual inspections are not value added.
Airplanes undergo a fairly rigorous inspection in the morning hours preceding the first flight of the day and further inspections are performed while cleaning the airplane between flights resulting in several man-hours per airplane per day. If any areas appear to be tampered with, a more thorough inspection will then be performed.
In one aspect, a system for monitoring activities relating to movable and removable items within a vehicle is provided. The system includes an electrical energy storage device, an energy harvesting device operable to store harvested energy in the electrical energy storage device, a sensor element configured to output signals corresponding to one or more of removal, installation, and a shift in position of a corresponding item within the vehicle, and a transmitter configured to receive the signals from the sensor element. The transmitter is also configured to transmit unique identification information and data corresponding to the signals received from the sensor element, where the unique identification information corresponds with a location of the item on the vehicle. The sensor element and the transmitter are configured to use energy from one or both of the energy harvesting device and the electrical energy storage device.
In another aspect, a method for monitoring activities related to one or more items within an aircraft is provided. The method includes configuring the items such that at least one activity associated with the item is operable as a triggering event to a sensor, transmitting a unique identification code associated with the sensor to a monitoring device upon determining that a triggering event has occurred, and correlating the unique identification code with a physical location within an aircraft for purposes of physical inspection.
The features, functions, and advantages can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings.
The methods and systems described herein are helpful in reducing costs and airport gate turnaround time associated with inspections of the various volumes, spaces, and doors associated with an aircraft. More specifically, the methods and systems relate to several specific devices, and associated methods, for wirelessly sensing modification, activity, and/or access events related to volumes, spaces or doors using various energy harvesting or “self-powered” sensors. These sensors are configured to detect and report such modification, activity and access events using wireless communications and the above mentioned battery-free sensors.
In operation, sensor 120 is operable to alert the low power, wireless sensor/transmitter 102 of the installation state of the bezel 114 (e.g., if the bezel 114 is in a closed or open position). In one embodiment, the sensor/transmitter 102 is programmed to transmit a unique identification code and a state (open/closed) of the sensor/transmitter 102 whenever the sensed condition changes. The sensor/transmitter 102 may also be programmed to wirelessly transmit it's unique identification code on a periodic basis, whether the state of the sensor 120 has changed or not, to provide a “sign of life” signal. In one embodiment, the low power, wireless sensor/transmitter 102 is installed in the housing 110, behind the light bezel 114.
The wireless sensor/transmitter 102 is powered by the lamps 112 behind the bezel 114. A photovoltaic cell 104, such as an amorphous silicon photovoltaic cell, is exposed to this light source. The cell 104 is utilized to maintain a charge on a battery and/or a capacitor (not shown in the Figure) which may or may not be located within the housing 110 or within the wireless sensor/transmitter 102. The battery and/or super-capacitor provide the energy needed to power the wireless sensor/transmitter 102.
In the figure, a magnetic material 122 is bonded to the hinged light bezel 114 such that it is adjacent to sensor 120 when the bezel 120 is in the closed position. When the bezel 114 is opened (swung downward), the magnetic material 122 moves away from the sensor 120 and the sensor/transmitter 102. In one embodiment, sensor 120 is a magnetic reed switch within the sensor transmitter 102 that senses that the magnetic material 122 is not nearby. When the magnetic material 112 is no longer proximate sensor 120, the reed switch therein changes state, causing the sensor/transmitter 102 to transmit its identification number, and other data indicating that the sensor 120 does not sense the magnetic material 122. Likewise, when the bezel 114 is closed, the sensor 120 senses the presence of the magnetic material (the reed switch again changes state) and the sensor/transmitter 102 transmits its identification number, and other data indicating that the switch is again closed. In one embodiment, a record of each bezel opening and closing occurrence is retained in a monitoring device so appropriate actions can be performed.
In one embodiment, the mechanical energy harvester of door assembly 200 may include a piezoelectric device that is caused to deflect or vibrate by the mechanical work, thus producing an electrical charge in the piezoelectric materials. In another embodiment, a piezoelectric material is bonded to an aircraft structure and is operable to undergo a strain based on a strain experienced by the aircraft structure under varying aircraft operational forces to produce the electrical charge;
In another embodiment, the mechanical energy harvester includes an electro-dynamic device including a coil of wire. A magnetic field is caused to move relative to the coil of wire to produce an electric current in the coil of wire. In one specific embodiment, the polarity of the generated electric charge (or polarity of first half-cycle of AC generated power) may be sensed by the sensor/transmitter 202 to detect whether the door 204 is going through an opening” or “closing” event.
Each wireless sensor/transmitter 202 generally includes one or more sensor(s), a microprocessor, and a radio transmitter. Additionally, each sensor/transmitter 202 includes a small energy storage device, such as a battery and/or a capacitor, in addition to an energy harvesting device. In various embodiments, the energy harvesting device converts ambient energy of one form (force, vibration, heat, flow, light) into electricity to power the sensor/transmitter 202 and/or charge an energy storage device. As a result, the sensor/transmitter 202 is completely wireless and powered either by a small energy storage device and/or by converting ambient energy in its surrounding environment. These energy generation and storage capabilities make the door assembly 200 very easy to install, particularly in a retrofit or after-market scenario, since no power or data wires need to be routed to the door assembly 200.
The sensor/transmitters 202 are, in one embodiment, configured to sample the sensor portion on a schedule (e.g. sample state of door every second). The sensor/transmitter 202 may also be triggered by an external event, related to where it is installed, to sense, for example, the act of physically opening a door. In another example, the sensor/transmitter 202 is configured to conform to a periodic schedule whereby it samples the state of the door every second and wirelessly reports whenever that state has changed, but at least every hour to provide a “sign of life” signal. As another example, the sensor portion of sensor/transmitter 202 is a switch that only awakens the microprocessor when it changes from an open to closed circuit, or visa versa. It is well known in the art of microprocessors to support such a polling or wake-on-demand function. As yet another example, the sensor/transmitter 202 includes a spring-loaded lever that is released when a hatch door is opened. This mechanical spring release action is converted to electricity and activates the sensor/transmitter 202 to transmit a corresponding message that indicates “hatch opened”. In this last example, the sensor transmitter 202 is powered by the change of state in the object it is intended to sense.
As illustrated in
Another packaging concept includes alternative energy harvesting devices connected to a sensor and transmitter combination, which may consist of, for example, a photovoltaic device exposed to a light source, such as sunlight or cabin lighting, a vibration harvesting device, such as a cantilevered piezoelectric beam, exposed to airplane or operational vibration, or a thermoelectric device exposed to a thermal gradient, such as a hot hydraulic line or the thermal gradient across the airplane insulation blanket as well as a thermoelectric device exposed to a thermal gradient between any two aircraft structures.
Another sensor/transmitter configuration 300 is illustrated in
With respect to
In the illustrated embodiment of the mechanical energy harvester 410, a flexible lever 412 is attached to the seat pan 414 typically under the seat cushion 402. Installation of the cushion 402 presses the lever 412 down, causing land number one 416 of lever 412 to engage a spring loaded lever 418 and activate a mechanical energy harvesting device within a wireless sensor/transmitter 420 causing it to transmit. Land number two 422 of lever 412 is configured to rest on the top 424 of the sensor/transmitter 420 to carry vertical loads through to the seat pan 414.
Upon removal of the seat cushion 402, flexible lever 412 will rebound, thus releasing the spring loaded lever 418. Release of the spring loaded lever 418 activates a mechanical energy harvesting device within wireless sensor/transmitter 420 causing it to transmit.
One sensor configuration is illustrated in
The principles of the photovoltaic powered light bezel wireless sensor/transmitter described above with respect to light assembly 100 are applied to sensing full removal, partial removal, and installation of cabin return air grills 502 from aircraft cabin side walls 504, except that in this embodiment, the photovoltaic cell is replaced by a thermoelectric generator 506 to provide electrical energy. In the illustrated embodiment, the thermoelectric generator 506 is located within an airplane structure behind or nearby the return air grill 502. The return air is utilized by the thermoelectric generator 506 to charge a battery or capacitor that is located within a transmitter/storage device 508. Transmissions from transmitter/storage device 508 include, for example, a unique identification number for the transmitter and an indication of whether the return air grill 502 is “installed” or “removed” from the cabin side wall 504.
One or more sensors 510 are used to detect when the return air grill 502 is installed, removed or partially removed and such an event results in a transmission being sent by the transmitter/storage device 508. In one embodiment, a magnetic reed switch may be used with, for example, a magnet bonded to the return air grill 502 and a magnetic reed switch mounted on an exterior 512 of the cabin side wall 504 such that the magnet causes the reed switch to close while the return air grill 502 is installed at that location. In the illustrated embodiment, the transmitter/storage device 508 is also mounted to the exterior 512 of the cabin side wall 504. A micro-switch may also be used as a sensor.
As illustrated, the thermoelectric generator 506 and a related heat sink 520 are mounted to a crease beam 530 that lies between two sections of insulation 532, 534 and that is mounted to an interior 540 of the aircraft outer layer 542. Thus, the thermoelectric generator 506 is able to generate electrical power for charging transmitter/storage device 508 from the thermal gradient between the generally warmer return air and the crease beam 506, which is generally colder during flight. Return air grill sensor assembly 500 is operable to allow a wireless transmission to be sent whenever a return air grill 502 is installed, removed or partially removed from the cabin side wall. Though the return air grill is located near the cabin floor 544, it is understood that such grills may be located in other places within an aircraft cabin.
With respect to all of the above described embodiments, a unique transmitter identification number is included in each wireless transmission. The unique transmitter identification number is correlated to the sensor's physical location. Therefore, transmissions from these sensors may be correlated to the associated physical locations. In one embodiment, a report may be generated that provides a listing of all physical locations where a transmission originated due to, for example, movement of a light bezel, or operation of an access door. In addition, the transmissions may be date/time stamped at the receiver with this information included with the report. As a result of such a report, only inspection in the specific physical locations listed in the report may be required, while other locations might not require such an inspection. To provide such a report, a database of sensor identification numbers and corresponding physical location is constructed and maintained, for example, at an airplane level. In addition, it should be noted that all of the above described sensor/transmitter embodiments may be incorporated in configurations where multiple sensors are interfaced to a single transmitter and/or a single energy storage device.
In addition, the above described transmitter devices, which generally are powered by photovoltaic cells, thermoelectric, and/or vibration are also programmed, in certain embodiments, to occasionally transmit a “sign of life” indication, which is useful in maintaining an accurate database of sensors and transmitters and ensuring that the many transmitters that may be implemented on an aircraft are all operational. The transmitters above may also transmit other prognostic information for diagnostic purposes, including, but not limited to, an energy state of on-board energy storage devices (e.g. min/max/average/current battery capacity or capacitor voltage), a state of photovoltaic cells (min/max/average/current voltage), checksum, and a wireless signal strength.
The energy harvesting features and low power configurations described herein provide installation capabilities where no data wiring, power wiring and primary batteries are required. Such configurations result in light weight installations that are relatively easy to install, simple to retrofit, and easily maintained. Another important point about the wireless, energy harvesting designs described herein is that such systems do not need to be wired into airplane power. The installation of the above described solutions enable an airline to install the sensing and monitoring devices in locations that may not have a readily available power source. Finally, methods of sensing that do not employ energy harvesting may be considered too costly or time consuming for airlines to implement.
It should also be noted that the above examples only, and that any of the described sensing mechanisms could be incorporated in any of the monitoring locations. For example, while the light bezel monitoring device is described as using a photovoltaic device, it is also possible to monitor the open/closed status of the bezel utilizing the above described piezoelectric device that is caused to deflect or vibrate by mechanical work, in this case the movement of the lighting bezel, thus producing an electrical charge in piezoelectric materials.
The embodiments are further intended to increase the efficiency of the above described inspection processes. In one example, those locations that have transmitted information indicated that some type of tampering has occurred, such as the opening of a light bezel or the removal of a return air grill, are the only locations subject to an extensive physical inspection before continued operation of the aircraft. Other locations may only need a periodic, cursory or visual inspection, thereby reducing the number of man-hours needed to fulfill search and inspection requirements.
While the above described embodiments are generally described in the context of employing energy harvesting devices for electrical power, it is also contemplated that embodiments of the described sensor/transmitter devices may utilize one or more primary batteries instead of, or in addition to, the energy harvesting capabilities.
Finally, while the described embodiments relate specifically to the energy harvesting techniques and the sensing of conditions, and the transmission of those conditions, it follows that certain embodiments include one or more receiving systems operable to receive the transmission from the sensor/transmitter, and that such a system is operable to record, store, and compile the data received from the transmitters. In one embodiment, the receiving system is operable to track the transmitters to ensure that they are active, and generate an indication if a transmitter is determined to be inactive. In such embodiments, a date and time stamp is generated by the receiving system. In conjunction with the receiving system, a user interface is contemplated from which a user can read, print, send, and/or relay the relevant sensor transmitter information as well as capture the resolution of the event(s) for a robust and traceable history.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
