U.S. patent application number 12/973997 was filed with the patent office on 2011-04-21 for wirelessly communicating sensor data to the internet.
Invention is credited to Steven Willard Arms, Michael John Hamel, Christopher Pruyn Townsend.
Application Number | 20110090888 12/973997 |
Document ID | / |
Family ID | 43879941 |
Filed Date | 2011-04-21 |
United States Patent
Application |
20110090888 |
Kind Code |
A1 |
Arms; Steven Willard ; et
al. |
April 21, 2011 |
Wirelessly Communicating Sensor Data to the Internet
Abstract
A method of wirelessly communicating sensor data includes
providing a wireless sensor module that includes a sensor and a
transmitting circuit. The transmitting circuit is connected for
wirelessly transmitting data derived from the sensor for receipt by
a receiver connected to the internet for providing information
derived from said sensor on the internet. The method also includes
using said sensor and wirelessly transmitting data derived from the
sensor.
Inventors: |
Arms; Steven Willard;
(Williston, VT) ; Townsend; Christopher Pruyn;
(Shelburne, VT) ; Hamel; Michael John; (Williston,
VT) |
Family ID: |
43879941 |
Appl. No.: |
12/973997 |
Filed: |
December 21, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10379224 |
Mar 5, 2003 |
7860680 |
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12973997 |
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60362432 |
Mar 7, 2002 |
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Current U.S.
Class: |
370/338 ;
340/870.07; 370/347 |
Current CPC
Class: |
H02J 13/0075 20130101;
H02J 7/025 20130101; H02J 50/90 20160201; H02J 50/80 20160201; H02J
50/12 20160201; H02J 7/00034 20200101; Y02B 90/20 20130101; H02J
13/00024 20200101; H02J 13/00026 20200101; Y04S 40/124 20130101;
Y04S 40/126 20130101; H02J 13/00017 20200101 |
Class at
Publication: |
370/338 ;
340/870.07; 370/347 |
International
Class: |
H04W 88/00 20090101
H04W088/00; H04Q 9/00 20060101 H04Q009/00; H04B 7/212 20060101
H04B007/212 |
Claims
1. A method of wirelessly communicating sensor data, comprising: a.
providing a wireless sensor module, wherein said wireless sensor
module includes a sensor and a transmitting circuit, wherein said
transmitting circuit is connected for wirelessly transmitting data
derived from said sensor for receipt by a receiver connected to the
internet for providing information derived from said sensor on the
internet; b. using said sensor; and c. wirelessly transmitting data
derived from said sensor.
2. A method as recited in claim 1, further comprising receiving
said wirelessly transmitted data with a receiver connected to the
internet and providing information derived from said sensor on the
internet.
3. A method as recited in claim 2, wherein said receiver includes a
first circuit and a second circuit, wherein said first circuit is
for receiving said wirelessly transmitted data, wherein said second
circuit is for communicating said information derived from said
wirelessly transmitted data on the internet.
4. A method as recited in claim 2, wherein said receiver includes
non-volatile memory and storing data derived from said sensor in
said non-volatile memory.
5. A method as recited in claim 2, further comprising a base
station, wherein said base station includes said receiver connected
to the internet.
6. A method as recited in claim 2, further comprising a plurality
of said wireless sensing modules, wherein said receiver is
configured to receive from each of said wireless sensing
modules.
7. A method as recited in claim 6, wherein said plurality of said
wireless sensing modules communicate using time division multiple
access (TDMA) and transmitting using TDMA.
8. A method as recited in claim 2, wherein said receiver is further
connected to a local area network.
9. A method as recited in claim 2, wherein said receiver includes a
receiver microprocessor, wherein said receiver microprocessor is
configured to provide error checking of said wirelessly transmitted
data, and providing error checking of wirelessly transmitted data
before providing said information derived from said sensor on the
internet.
10. A method as recited in claim 2, further comprising providing an
apparatus for providing said information derived from said sensor
on the internet, wherein said apparatus includes at least one from
the group consisting of a computer, a router, and a cable modem,
wherein said receiver communicates said information to said
apparatus.
11. A method as recited in claim 10, wherein said receiver includes
a cell phone, and using said cell phone for said providing said
information derived from said sensor to said apparatus for
connection to the internet.
12. A method as recited in claim 2, wherein said receiver provides
bidirectional wireless communication with the internet, and using
said receiver for said bidirectional communication.
13. A method as recited in claim 2, wherein said receiver provides
said information to the internet in XML data format.
14. A method as recited in claim 1, wherein said wireless sensing
module further includes sensor signal conditioning, an A/D
converter, and a microprocessor.
15. A method as recited in claim 1, wherein said wireless sensing
module further includes a timer, and using said timer to set time
for said transmission.
16. A method as recited in claim 1, wherein said wireless sensing
module further includes a plurality of sensors and a multiplexor,
and wirelessly transmitting data derived from said plurality of
sensors.
17. A method as recited in claim 1, wherein said wireless sensing
module further includes an RF transceiver, wherein said
transmitting circuit is part of said RF transceiver, and receiving
at least one from the group consisting of data and instructions
with said transceiver.
18. A method as recited in claim 1, wherein said wireless sensing
module further includes an energy storage device, and using said
energy storage device to power said transmitter.
19. A method as recited in claim 1, wherein said wireless sensing
module further includes a data storage device, and using said data
storage device to store data prior to transmitting.
20. A method as recited in claim 1, wherein said sensor includes at
least one from the group consisting of a thermocouple, a strain
gauge, a load cell, a torque transducer, and a displacement
transducer.
21. A method as recited in claim 1, wherein said receiver includes
a cell phone, and using said cell phone for said providing
information derived from said wirelessly transmitted data on the
internet.
22. A method as recited in claim 1, wherein said wireless sensing
module includes a power receiving circuit, and using said power
receiving circuit for powering said wireless sensing module.
23. A method as recited in claim 22, further comprising an unmanned
vehicle, and using said unmanned vehicle to approach said wireless
sensing module, wherein said unmanned vehicle includes an unmanned
vehicle power transmitting circuit, and using said unmanned vehicle
power transmitting circuit for providing power to said power
receiving circuit.
24. A method as recited in claim 23, wherein said unmanned vehicle
power transmitting circuit is configured to wirelessly transmit
power to said wireless sensing module and using said unmanned
vehicle power transmitting circuit to wirelessly transmit power to
said wireless sensing module.
25. A method as recited in claim 22, wherein said wireless sensing
module includes an energy storage device for storing energy
received by said power receiving circuit and using said energy
storage device for storing energy received by said power receiving
circuit.
26. A system, comprising: a base station having a connection to the
internet; and a wireless sensor module including a sensor and
transmitting circuit, wherein said transmitting circuit is
connected for wirelessly transmitting data derived from said
sensor, wherein said base station includes a first circuit for
receiving said wirelessly transmitted data, wherein said base
station includes a second circuit for communicating information
derived from said data to the internet.
27. A system as recited in claim 26, wherein said base station
includes a cell phone, wherein said second circuit includes said
cell phone.
28. A system as recited in claim 26, wherein said second circuit
provides bidirectional wireless communication with the
internet.
29. A system as recited in claim 26, wherein said second circuit
provides said information to the internet in XML data format.
30. A system as recited in claim 26, wherein said sensor module
further comprises a sensor module receiving circuit.
31. A system, comprising a wireless sensor module, wherein said
wireless sensor module includes a sensor and a transmitting
circuit, wherein said transmitting circuit is connected for
wirelessly transmitting data derived from said sensor to a receiver
connected to the internet for providing information derived from
said sensor on the internet.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/379,224, filed Mar. 5, 2003, incorporated herein by
reference. Applicant claims the benefit of provisional patent
application 60/362,432, filed Mar. 7, 2002, incorporated herein by
reference.
[0002] This patent application is related to the following US
patent applications: [0003] Ser. No. 09/731,066, docket number
1024-034, filed Dec. 6, 2000; [0004] Ser. No. 09/801,230, docket
number 1024-036, filed Mar. 7, 2001; [0005] Ser. No. 09/768,858,
docket number 1024-037, filed Jan. 24, 2001; [0006] Ser. No.
09/114,106, docket number 1024-041, filed Aug. 11, 1998; [0007]
Ser. No. 09/457,493, docket number 1024-045, filed Dec. 8, 1999;
[0008] 60/443,120, docket number 115-008, filed Jan. 28, 2003; and
[0009] Ser. No. 10/379,223, docket number 115-008, filed Mar. 5,
2003; all of which are incorporated herein by reference.
FIELD
[0010] This patent application generally relates to power
management of sensors. More particularly, it relates to an improved
system for powering and communicating with sensors. Even more
particularly, it relates to an energy harvesting system for
powering and communicating with sensors.
BACKGROUND
[0011] Sensors are being developed for use in roads, bridges, dams,
buildings, towers, and vehicles that may provide many different
types of information, including displacement, strain, speed,
acceleration, temperature, pressure, and force. Providing power to
the sensors and communicating data from the sensors has been
difficult. The present patent application provides a way to more
efficiently provide power for sensors and to communicate with
sensors.
[0012] Inspection of civil structures are very important for public
safety. Litigation costs due to structural failure not only hurts
the department held responsible for the failure, but the litigation
takes money away from other projects, which in turn, increases
public risk by reducing monies available for future maintenance and
inspections. We propose to develop an autonomous robotic sensor
inspection system capable of remote powering and data collection
from a network of embedded sensing nodes, and providing remote data
access via the internet. The system will utilize existing
microminiature, multichannel, wireless, programmable Addressable
Sensing Modules (ASM's) to sample data from a variety of sensors.
These inductively powered nodes will not require batteries or
interconnecting lead wires, which greatly enhances their
reliability and lowers costs.
[0013] Networks of sensing nodes can be embedded, interrogated, and
remotely accessed in applications where visual inspection by people
is not practical due to: physical space constraints, remote
geographic locations, high inspection costs, and high risks
involved for those performing the inspections. The sensors can
indicate the need for repair, replacement, or reinforcement, which
will reduce the risks of catastrophic failures and would be useful
after natural disasters. Sensors of peak displacement, peak strain,
corrosion, temperature, inclination, and other
microelectromechanical sensors (MEMS), are now capable of
embeddment in structures, and are compatible with our ASM's. The
availability of critical structural health data on the internet
would greatly assist highway engineers and scientists, to improve
their working database on these structures, which will improve our
understanding of the safety of civil structures and their requisite
maintenance.
[0014] In the majority of civil structures, there is little data to
help an engineer model the behavior of a structure before it is
built or after rehabilitation. This leaves an engineer to rely on
past experience to determine what type of repair to apply without
truly knowing its affect on the physical strength of the structure.
Physical measurements and on-site examinations are performed to
assess structural integrity. Typically, maintenance and repairs are
not performed until serious structural damage can be seen. In some
cases, such as marine structures, damage occurs out of visual site
where only specialized sensors can detect distress. Natural
disasters such as floods, earthquakes, hurricanes, ice storms, and
tornadoes, as well as everyday use, collisions, deicing salts,
drainage, and corrosion compromise the safety of civil
structures.
[0015] The soundness of on-site evaluations depends upon the people
performing the inspection. The accuracy of the inspection depends
on many factors: how thorough is the inspector, their ability to
detect unsafe conditions, and the resources available--personnel,
financial, equipment, and workload. Civil structures are large and
can be located in unsafe and harsh environments. Traffic flow,
structure height, the grade around the structure, underwater
(pollution), and confined spaces (air poisoning) are a few
obstacles inspectors have to overcome. Water pollution has made
inspectors sick while checking bridge piers and abutments for
scour. Seasonal thawing can increase river flow making bridge
inspection dangerous. Steep embankments increase the risk of
vehicle overturn. Having a way to interrogate embedded sensing
nodes with multiple sensing elements (strain, temperature,
vibration, depth, etc.) and inspect structures remotely would save
time, equipment costs, personnel costs, and lower health risks to
inspectors and the people using the structure.
[0016] Environmental influences such as scour, wind, waves,
collisions, and corrosion weaken bridge integrity. Scour occurs
when (1) sediment is carried away around bridge piers or abutments
(2) sediment is removed from the bottom and sides of a river due to
the bridge creating a narrower than natural channel for the river
to flow through (3) and by everyday river flow carrying away
sediment from the river bottom. Floods are the main cause of scour,
eroding the ground that supports the bridge. Between the years 1961
and 1976, 46 of 96 major bridge failures were due to scour near
piers. In 1987 the Interstate Highway bridge over Schoharie Creek
in New York State collapsed killing 10 people, a total of 17
bridges were lost in New York that year due to scour. In 1989 a
bridge over the Hatchie River in Covington, Tenn. failed due to
scour killing 8 people.
[0017] Scour is measured using a number of techniques, such as:
fathometers, fixed- and swept-frequency continuous seismic
reflection profiling, and ground-penetrating radar. In each case an
inspector has to be present to operate the equipment. The ability
to monitor scour, as well as peak strain, during a flood using a
remote interrogation process would increase safety, give real-time
feedback, and potentially save lives.
[0018] Railroads provide another opportunity for remote monitoring
of embedded sensors. Aug. 10, 1997 in Kingman, Ariz. an Amtrak
passenger train derailed as it traveled on a bridge spanning a
river. A storm suddenly moved in dumping 1.76'' of rain causing a
flash flood. Inspectors had inspected the bridge not more than
three hours before the accident, warning sensors located on the
bridge failed to stop or warn the train of damage. Remote
interrogation hardware could be used to test track continuity as
well as measure truss integrity.
[0019] Sensors can be embedded in or placed on structures to record
physical measurements. Buildings, such as the Millikan Library at
Caltech and Factor Building at UCLA as well as dams (Winooski dam
in Winooski, Vt.) have been gauged with fiber optic sensors to
monitor performance. All of the sensors used rely on power being
constantly supplied to the sensor to operate and cables (with
connectors) must be embedded in the structure for power and
communication. This works well when the structure is easily
accessible and power is always available, or, if battery powered,
the batteries can be replaced easily. But power is not always
available at the time when readings are needed most and batteries
can only be embedded if they can be recharged. If the structure is
located in a remote area, data may not be accessible when needed.
Embedding cable is costly and time consuming during manufacture.
Cabling also elevates the risk of failure during everyday operation
and disasters.
[0020] Presently there is neither a means nor a system that can
remotely interrogate an array of independent sensing nodes located
throughout a structure. "The Robotic Inspector" (ROBIN, U.S. Pat.
No. 5,551,525) was developed at the Intelligent Robotics Lab at
Vanderbilt University. ROBIN was developed to inspect man-made
structures. Advantages of ROBIN are that it is highly mobile and
has versatile fixtures. However, ROBIN carries specific sensors in
its limited payload area and is also restricted by a power
cord.
[0021] Visual/Inspection Technologies, Inc. developed a product
called SPOT that uses a pan & tilt zoom camera for pipe
inspection. Although SPOT can travel into areas that people cannot,
it requires an on-site person for operation, it is only equipped
with a camera, it can weigh up to 120 lbs., and SPOT is specific to
pipe applications.
[0022] NASA has developed a robot to search Antarctica for
meteorites and rocks. The robot "Amadeus Nomad" can travel in sever
weather conditions which constantly impede human travel. Amadeus
Nomad requires minimal human assistance but uses onboard sensors
for inspection.
[0023] Insects, although possessed of severely limited
computational abilities (very small brains) can deal effectively
with their environment. An insect's ability to navigate, respond to
hazards, and achieve its goals (finding food and a mate) puts any
robot to shame. Behavior Control (developed by Prof. Rodney Brooks
at MIT in 1986) attempts to encapsulate the computational
efficiencies that insects and other organisms use to achieve their
impressive results. Behavior Control has proven an effective robot
programming strategy for handling dynamic and/or poorly modeled
environments. Behavior Control's sensor based strategy produces
robots that respond quickly to changing conditions, react robustly
to unexpected situations, and degrade gracefully in the presence of
sensor faults. The most visible recent success of the Behavior
Control methodology was Sojourner, the Mars rover. Sojourner was
the culmination of several years of development of Behavior Control
robots (Rocky I through Rocky IV) at NASA's Jet Propulsion
Laboratory, JPL.
[0024] There is a need for robust, insect-like, autonomous
structural inspection systems which can be used with easily
deployed or embedded sensing nodes; and for data collected from
these structures to be readily over the Internet. None of the
available systems provide power to the sensors and communicate data
from the sensors as effectively as possible. Thus, a better system
for powering sensors and storage devices, and for transmitting data
gathered by sensors is needed, and this solution is provided by the
following description
SUMMARY
[0025] One aspect of the present application is a method of
wirelessly communicating sensor data includes providing a wireless
sensor module that includes a sensor and a transmitting circuit.
The transmitting circuit is connected for wirelessly transmitting
data derived from the sensor for receipt by a receiver connected to
the internet for providing information derived from said sensor on
the internet. The method also includes using said sensor and
wirelessly transmitting data derived from the sensor.
[0026] Another aspect of the present application is a system
comprising a base station having a connection to the internet and a
wireless sensor module. The wireless sensor module includes a
sensor and transmitting circuit. The transmitting circuit is
connected for wirelessly transmitting data derived from the sensor.
The base station includes a first circuit for receiving the
wirelessly transmitted data. The base station includes a second
circuit for communicating information derived from the data to the
internet.
[0027] Another aspect of the present application is a system,
comprising a wireless sensor module and a transmitting circuit. The
wireless sensor module includes a sensor and transmitting circuit.
The transmitting circuit is connected for wirelessly transmitting
data derived from the sensor to a receiver connected to the
internet for providing information derived from the sensor on the
internet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The foregoing will be apparent from the following detailed
description as illustrated in the accompanying drawings, in
which:
[0029] FIG. 1 is a flow chart of judicious use of power on a
wireless sensing module which is kept in sleep mode until it
receives a signal that it should transmit;
[0030] FIG. 2 is a block diagram of a first embodiment of a
wireless sensing module having no on-board power supply;
[0031] FIG. 3 is a block diagram of a second embodiment of a
wireless sensing module having a rechargeable on-board power
supply;
[0032] FIG. 4 is a block diagram of an unmanned vehicle having a
circuit to read a wireless sensing module having RFID transponder
communications circuits, an RF transceiver for communicating with a
home base, and a coil for transmitting power to a wireless sensing
module;
[0033] FIG. 5 is a block diagram of an unmanned vehicle similar to
FIG. 4 but without the RFID transponder and having a circuit to
recharge a battery or capacitor on a wireless sensing module;
[0034] FIG. 6 is a block diagram of a first embodiment of a
unmanned vehicle and a network of wireless sensing modules each
with rechargeable power supplies capable of being recharged by the
unmanned vehicle;
[0035] FIG. 7 is a block diagram similar to that of FIG. 6 in which
power supplies are charged once or are recharged from the
environment rather than from the unmanned vehicle;
[0036] FIG. 8 is a block diagram showing a scalable wireless web
sensor network;
[0037] FIG. 9 is a block with more details of the scalable wireless
web sensor network of FIG. 8, including sensors, receivers, LAN, PC
console, router, cable modem and internet;
[0038] FIG. 10 is a block diagram showing a double scalable
wireless web sensor network in which data from sensors is
wirelessly transmitted to a receiver that then wirelessly transmits
to a PC console connected to the internet; and
[0039] FIG. 11 is a flow chart showing user-initiated remote data
acquisition.
DETAILED DESCRIPTION
[0040] The present applicants recognized that unmanned vehicle or
robot 20 could approach and wirelessly electromagnetically power a
separate device, such as wireless sensing module 22, as shown in
FIG. 7, or to an actuator (not shown). Unmanned vehicle 20 could
wirelessly provide the power needed by wireless sensing module 22
for operating wireless sensing module 22 while unmanned vehicle 20
is nearby. The present applicants also recognized that unmanned
vehicle 20 could also periodically wirelessly provide the power for
charging or recharging batteries or capacitors 24 included with
wireless sensing module 22 so wireless sensing module 22 could
operate and transmit while unmanned vehicle 20 is far away. The
present applicants also recognized that unmanned vehicle 22 could
also wirelessly receive data from sensor 26 as it is collected by
sensor 26. Alternatively, unmanned vehicle 20 could collect data
that was collected over time and stored in data logging system 28
included with wireless sensing module 22. The present applicants
recognized that the communication between wireless sensing module
22 and unmanned vehicle 20 can be by radio or by switched reactance
modulation.
[0041] Unmanned vehicle 20 can have wheels 30 for rolling about on
a structure (not shown). Wheels 30 can be magnetic so unmanned
vehicle 20 sticks to iron containing structures, such as bridges
and can crawl around on the structure. It can also have wings for
flying. It can be able to recharge while in flight. It can have
fins for traveling through water. Other forms of locomotion are
also possible. It can be able to recharge batteries 24, interrogate
wireless sensing modules 22, or turn on or off actuators (not
shown) in inaccessible places, such as underwater or in difficult
to reach structures.
[0042] A data logging transceiver is described in copending patent
application Ser. No. 09/731,066, ("the '066 application")
incorporated herein by reference. The '066 application was filed
Dec. 6, 2000 and has docket number 1024-034. The '066 application
describes a remotely activated wireless high speed data logging
system that receives instructions and transmits data accumulated
over time and stored in memory. A wireless high speed data logging
system with a transceiver, as described in the '066 application can
be used in the present patent application to store data accumulated
from the sensor and can then transmit the data. The data may be
transmitted directly to a base station. It can also be transmitted
to the unmanned vehicle, such as a drone or robot, when the
unmanned vehicle is nearby.
[0043] Mobile charge monitoring line 36 to processor 38 is used to
optimize the position of charging unit 40 on robot 20. Preferably a
minimal amount of power is retained in battery 24 so wireless
sensor module 22 can operate and its processor 38 can help robot 20
position its charging unit 40. When current is below a minimum the
wireless sensor module asks charging unit 40 to move to optimize
its position. If totally depleted wireless sensor module 22 could
only do that if charging unit 40 on unmanned vehicle 22 is
providing enough power to start circuitry 42 on wireless sensor
module 22. Wireless sensor module 22 can look at amplitude of
current or at spatial derivative to know which direction to move.
Positioning can also be accomplished by using the received signal
strength from RF transmitter 50. This can be used to help robot 20
find wireless sensor module 22 for coarse positioning. Then,
charging circuit monitoring line 36 could be used to more finely
tune position of robot's coil 52 (FIG. 4).
[0044] Charge receive circuit 54 on wireless sensing module 22 has
tunable tank circuit 56 with tuning capacitor 58, as shown in FIG.
3, to optimize resonance of wireless sensing module coil 60 at the
frequency generated by coil 52 on robot 20. This can be a fixed
frequency. However, it may be desirable to be able to adjust the
frequency for exciting and charging depending on the medium through
which radiation is being transmitted. For air, high frequencies can
be used, such as 200 kHz to 13.5 MHz. For transmitting through
metals it is desirable to keep the frequency between 2 kHz and 20
kHz, as described in the 1024-041 application. One can adjust
resonance of coil 60 from 2 kHz to 200 kHz by changing the value of
tuning capacitor 58.
[0045] By nature, radio frequency (RF) transmitters 62 or
transceivers 62' tend to be power consumptive. The present patent
application does not necessarily need RF transmitter 62 or an RF
oscillator for communication. By reducing the power for
communication, the distance between wireless sensing module 22 and
a receiver on robot 20 can be increased. If robot 20 is providing
the power for RF transmitter 62 or transceiver 62' it has to be
close enough to both provide enough power to start up processor 38
on wireless sensor module 22 and to provide power to operate
transmitter 62, 62'. If RF transmitter 62, 62' is eliminated then
less power is used and the distance can be increased. One way to
accomplish this is to replace RF transmitter 62, 62' with radio
frequency identification (RFID) transponder tag 66, such as is
available from Microchip Technologies (Chandler, Ariz.). Use of
RFID requires that robot 20 must be located close to a transponder
68 on robot 20 but not be as close as would be required if an RF
transmitter were used at wireless sensor module 22. The biggest
disadvantage of both techniques is that information is transmitted
only when robot 20 is close if the wireless sensor module has no on
board power supply.
[0046] With the oscillator for RF transmitter 62, 62' in the
circuit of wireless sensor module 22 and with on board power source
24, the transmission of data can be over a greater distance. When
charging with robot 20 it is best to turn off or putwireless sensor
module 22. Alternatively wireless sensor module 22 can be put into
sleep mode to draw minimal power while charging.
[0047] In addition to communication between single unmanned vehicle
20 and wireless sensing module 22, there can be many unmanned
vehicles 20, and they can also communicate with each other. In
addition to charging wireless sensing modules 22, unmanned vehicles
20 can also charge each other. Similarly, wireless sensing modules
22 can talk to each other, to unmanned vehicles 20, to a base
station (not shown), or to a remote receiver (not shown), such as a
satellite. Communication from wireless sensing module 22 depends
largely on power available at wireless sensing module 22, and the
present patent application solves this power problem by using a
mobile recharging technique.
[0048] Wireless sensor modules 22 can be miniaturized by using tiny
on board rechargeable power supply 70 including charging circuitry
72 and energy storage 24. Energy storage 24 is charged or recharged
by recharging robot 20. For example for wireless sensing modules
embedded in a structure in a space vehicle, many wires extending
from each of the wireless sensing modules to a solar panel can be
avoided by providing small battery or capacitor 24 with each
wireless sensing module 22. Robot 20 is provided that includes
larger battery 74 that may be recharged using the solar panel.
Robot 20' travels to each wireless sensing module 22 and charges
each of the smaller batteries or capacitors 24. Robot 20 can also
interrogate wireless sensing modules 22 and obtain sensor data and
module ID data.
[0049] As an alternative, in applications where batteries are
undesirable, robot 20 can provide power to wireless sensing modules
22 and interrogate wireless sensing modules 22 that may be embedded
in a structure. Data, including identification, sensor calibration
and type, and sensor data may be stored on robot 20. These data can
also be transmitted directly from robot 20 as it is received.
[0050] Energy to run wireless sensing module 22 or a network of
wireless sensing modules 22 can also be taken directly from the
environment in some situations. In one embodiment each wireless
sensing module 22 in a network has a power source that may be a
battery or may be one that takes energy from the environment.
Copending patent application 115-008, incorporated herein by
reference, filed on the same day as this application, more fully
describes a system for harvesting energy from the environment. Each
wireless sensing module remains in sleep mode to conserve power.
Wireless sensing module 22 wakes up periodically to determines
whether a robot is near by checking for its transmitted signal.
Little power is needed for this check. If robot 20 is close then
wireless sensing module 22 will transmit to robot 20. The
transmission can be periodic to avoid collisions with transmissions
from other wireless sensing modules. Periodic transmission would
include a randomization timer that allows time division multiple
access (TDMA) from multiple wireless sensing modules on the
network. Wireless sensing module 22 may initially be in sleep mode,
as shown in step 80 of FIG. 1. It wakes up after a preprogrammed
time period, as shown in step 82. Its receiver is switched on to
listening mode, as shown in step 84. As shown in step 86, if it
detects a unique code from a robot it can transmit data, as shown
in step 88 through antenna 90 at a time interval set by
randomization timer 92 for collision avoidance. If no signal is
detected from a robot, wireless sensing module 22 goes back to
sleep, as shown in step 94.
[0051] Randomization timer 92 is provided to allow networks of
wireless sensor modules 22 to transmit on the same RF channel with
a statistically small percentage of RF collisions between wireless
sensor module transmissions on the network. The advantage is that
transceiver or receiver 100 on robot 20 need only receive signals
on one RF channel, allowing it to be smaller and lower in power
consumption than a receiver designed to handle many RF frequencies.
A system for data collection and internet distribution of data from
receiver 100 designed to operate with a network of wireless sensing
modules 22 using these TDMA techniques is provided in FIGS. 7-11
and described herein below.
[0052] Battery 24 on wireless sensing module 22 can be charged
wirelessly by robot 20 using electromagnetic radiation from robot
20 to wireless sensing module 22. Once recharged wireless sensing
module 22 can send data periodically without robot 20 having to be
nearby. Wireless sensing module 22 has either a battery or
capacitor 24 to store energy received wirelessly from robot 20.
Wireless sensing module 22 can use that energy to transmit a long
distance without robot 20 having to visit. For example, small thin
rechargeable batteries capable of infinite recharge cycles would
provide the ability to transmit a shorter distance multiple times
or a longer distance fewer times. Such a battery could transmit 20
miles if the transmission is only once a year or if larger
batteries are provided it could transmit more frequently. Or it
could transmit 20 feet many times. For example, a 20 mW transmitter
can transmit about 1/3 mile and using a lithium ion AA battery
which provides about 1000 mA hours on one charge. A transmitter
operating at 3V dc and consuming 10 mA would consume 30 mW of power
while transmitting. This system would be able to transmit for 33
hours continuously on the lithium ion battery. Such a battery
allows lengthening time between robot visits. An advantage of the
battery is that the system can be active and can sample and log
data from sensors using stored energy so more information can be
included in the later transmission.
[0053] Having a power source at each wireless sensing module 22,
such as rechargeable battery or storage capacitor 24, is a big
advantage over a system that can only transmit when robot 20 is
near. Without a local power source, wireless sensing module 22 can
only transmit in real time and data is missed when robot 20 is
away. Acquiring and logging data from sensors 26 consumes one tenth
as much power as is used transmitting data from sensors 26. So when
acquiring and logging data battery 24 can last much longer, over
300 hours using the same lithium ion battery.
[0054] Wireless sensing module 22 can also transmit when there is
an event. Wireless sensing module 22 can transmit the information
that it needs its battery recharged, that there is a problem sensed
at one or more wireless sensing modules 22, that it has updated
data, or that all is OK, and it does not need another charge for
another 20 days. Robot 20 can have a camera (not shown) as one of
its sensors to give it visual inspection capability. In addition to
use for powering or communicating with wireless sensing modules 22,
unmanned vehicle 20 of the present patent application can also be
used to provide power and communicate with actuators, such as a
relay, solenoid, piezoelectric or shaped memory alloy.
[0055] Rechargeable battery 24, such as a lithium ion battery, a
capacitor, or a fuel cell can be used on wireless sensing module
22. Super capacitors are very efficient large capacitors in small
packages.
[0056] For underwater applications a robot interrogator can also be
used but it would require close proximity due to RF attenuation in
water. For example, one underwater application would be a robot 20
to interrogate a network of wireless sensing modules 22 designed to
measure strain and permanent deformation of welds of an off shore
oil pipeline (not shown). In this case robot 20 gets close to each
wireless sensing module 22 as it moves up and down the pipe
line.
[0057] Preferably, each wireless sensing module 22 in a wireless
sensing module network has a 16 bit identification code so robot 20
can tell which wireless sensing module 22 it is near and also tell
its physical location. Physical location of wireless sensing module
22 can be used by robot 20 to help it determine direction and
distance to the next wireless sensing module 22. Preferably robot
20 would carry an orientation sensing module such as described in
Ser. No. 09/457,493, docket number 1024-045, filed Dec. 8, 1999,
incorporated herein by reference.
[0058] Robot 20 can be autonomous, semi-autonomous, or it can be
remote controlled. An autonomous robot may be programmed to follow
a preset path. Preferably robot 20 would include light, magnetic,
or touch sensors for providing feedback to follow a marked path.
The marked path could be a painted stripe, a series of magnets, or
a series of bumps.
[0059] Under remote control robot 20 may be directed in real time.
It can also be directed by instructions from wireless sensing
modules 22. Robot 20 can contain a navigation system. A component
of that navigation system can include a solid state orientation
sensor, as described in copending U.S. patent application Ser. No.
09/457,493, docket number 1024-045, filed Dec. 8, 1999,
incorporated herein by reference.
[0060] FIGS. 2 and 3 show block diagrams of two embodiments of
wireless sensing modules 22a, 22b. FIG. 2 shows the embodiment that
has no battery or other energy storage device and is externally
powered. Electromagnetic transmission from an unmanned vehicle is
received at LC tank circuit 56' including coil 60 and capacitor 58.
This ac signal is rectified and regulated in rectifier and
regulator circuit 96, to provide dc power for running
microprocessor 38, multiplexor 98, amplifier 100, a/d converter
102, non-volatile memory 28', and sensors 26.
[0061] Non-volatile memory 28' contains an identification address,
sensor calibration coefficients, and data from sensors 26 collected
since the previous successful interrogation or data transfer.
Processor 38 also controls power to sensors to minimize power used
by the sensors.
[0062] Digital data is communicated from various sensors 26 by
digitally varying the reactance of tank circuit 56 used to receive
power by wireless sensing module 22a. This is accomplished by
providing the signal along coil impedance control line 105 from
microprocessor 38 to transistor switch 104 that inserts small
capacitor 106 in and out of tank circuit 56', as shown in FIG. 2.
Coil impedance control line 105 controls the state of transistor
switch 104 which controls whether capacitor 106 is in circuit 56',
and the impedance of this circuit can be detected by the reader on
robot 20.
[0063] FIG. 3 shows the embodiment of wireless sensing module 22b
that has an on board rechargeable energy storage device, such as a
battery or capacitor 24. For recharging, electromagnetic
transmission from unmanned vehicle 20 is received at LC tank
circuit 56 including coil 60 and capacitor 58. This ac signal is
rectified and regulated in charging circuitry 108 to provide dc
power for charging energy storage device 24. Microprocessor 38,
multiplexer 98, amplifier 100, a/d converter 102, data storage
device 28, 28', RF transceiver 62', and charging circuitry 108 are
all powered from energy storage device 24. Processor 38 may control
power to sensors 26 to minimize power drawn by wireless sensing
module 22b. Data from various sensors 26 are converted to digital
form and directed from microprocessor 38 to RF transceiver 62'
along digital data line 110 for transmission from RF antenna 50.
Data or instructions can also be received by wireless sensing
module 22b and the data transferred from RF transceiver 62' to
microprocessor 38. Data storage device 28 can be non-volatile
memory and it may store an identification code, sensor calibration
coefficients, data from the sensors that was stored since the last
successful interrogation or data transfer, and the data received
from transceiver 62'. Wireless sensing module 22 can have charge
monitoring line 36 to sense how well coupled wireless sensing
module 22 is with the power transmitting source, such as unmanned
vehicle 20. It can also have RF signal strength line 112 that also
senses how well coupled (electromagnetically) wireless sensing
module 22 is with unmanned vehicle 20. Charge monitoring line 36
and RF signal strength line 112 can both be used to help direct
unmanned vehicle 20 to find or more closely approach wireless
sensing module 22. Unmanned vehicle 20 would be directed to move in
the direction of larger signal amplitude signal. The RF signal on
RF signal strength line 112 may be used at larger distances and the
charge monitoring signal on charge monitoring line 36 at closer
distances.
[0064] FIGS. 4 and 5 show block diagrams of two embodiments of
unmanned vehicle or robot 20. FIG. 4 shows the embodiment of an
unmanned rolling vehicle that has no charging circuit and FIG. 5
shows the embodiment as modified to provide for unmanned vehicle
20a, 20b being used to wirelessly charge battery or capacitor 24 on
wireless sensing module 22. In both embodiments, battery 74 on
unmanned vehicle 20a, 20b provides power to run its circuitry, its
RF transmissions and RF receptions, and to provide power for its
motors 114 for locomotion. Motors 114 are controlled by switching
electronics 116 and are connected to activation mechanics 117.
Navigation unit 118 can be provided for assisting it in determining
its location and the location of wireless sensing modules 22.
Microprocessor 120 controls oscillator 122 for providing
transmissions at coil 52 for powering wireless sensing module 22
(FIGS. 4 and 5) or for recharging battery or capacitor 24 on
wireless sensing module 22 (FIG. 5). Microprocessor 126 receives
input from light and touch sensors 128. Output of oscillator 122 is
amplified by power amplifier 124. Data may also be transmitted or
received by RF transceiver 100 through antenna 130 with the data
coming from or stored in non-volatile memory 126 on board unmanned
vehicle 20a, 20b. In FIG. 4 RFID transponder reading circuit 132,
such as available from Microchip Technologies Corp, may be used in
order to read data encoded by wireless sensing module 22 having
switched reactance as shown in FIG. 2. In FIG. 5 the RFID reader
can be eliminated if wireless sensing modules having switched
reactance, as shown in FIG. 2, do not need to be interrogated.
[0065] FIG. 6 shows the system with network of wireless sensing
modules 22' having rechargeable power supplies 24 that are served
by unmanned vehicle 20.
[0066] FIG. 7 shows the system with a network of wireless sensing
modules 22'' having power supplies 24 that are served by unmanned
vehicle 20 but unmanned vehicle 20 gets close enough to collect
data but does not have to recharge power supplies 24' on wireless
sensing modules 22. This would be advantageous where energy can be
harvested from the environment, such as with solar cells,
piezoelectric vibration transducers, and inductive transformers
located near power lines. A manned or unmanned platform can be
used. A platform that is either stationary or mobile can also be
used.
[0067] The scalable wireless web sensor networks employ
transmitters with direct sensor inputs and receivers, employing
time division multiple access (TDMA) techniques, and multiple
transmitters that (each with a unique address) can communicate
digital data to a single receiver, as shown in FIG. 8.
[0068] The wireless web sensor networks are scalable and can
collect data from up to 1,000 sensors via a single receiver. The
receiver is Ethernet enabled and acts as a web server, thereby
providing the user with data via a browser or an XML
application.
[0069] The performance of the network is applicable for structural,
agricultural, environmental, military and industrial applications.
This system can collect data from hundreds of transmitters, and by
utilizing this web-based system allow the information to be shared
with an unlimited number of users.
[0070] The receiver uses narrowband RF communications at 418 MHz. A
functional block diagram of the system is provided in FIG. 8.
[0071] Each transmitter Tx includes sensor signal conditioning,
multiplexer, 16 bit A/D converter, microprocessor, and RF link, as
shown in FIGS. 6 and 7. The transmitters are compatible with a wide
variety of sensors, including thermocouples (cold junction
compensated), strain gauges, load cells, torque transducers, and
displacement transducers (DVRT's).
[0072] A sleep timer with random wake-up, as shown in FIG. 1,
allows multiple periodic transmitters to operate on the same
communications channel with a very low collision probability. At
update rates of 30 minutes from each transmitter, up to 1000 remote
transmitters can communicate to a single RF receiver.
[0073] The receiver includes a single board computer, available,
for example, from Rabbit Semiconductor, with Ethernet capability,
built in XML and HTML (internet enabled) file transfer protocols,
data storage capability (10 Megabytes) and a web server. The
receiver detects data from a specific address on the network of
sensors and transmitters, and logs the information in its
non-volatile memory. Receiver Rx, shown in FIG. 8, includes
microcontroller 38 (FIGS. 6 and 7) that performs error checking of
the RF signal, and outputs a serial (RS-232) data stream to the
single board computer. The single board computer and the IP address
can be programmed to provide data output in extensible markup
language (xml) data format. Receiver Rx can be a mobile robot, as
described herein above or it can be located on a operator
controlled vehicle or hand-carried platform or it can be located on
a fixed platform.
[0074] The receiver can recognize inputs from an "ad hoc" network
of transmitters, and record data from this network over time, along
with calibration data unique to each sensor. Depending on the
sensor being employed, a transmitter can support up to 5 separate
sensors (channels).
[0075] The web server interrogates the single board computer from a
standard web browser (MicroSoft's Internet Explorer or Netscape's
Navigator) to receive multi-channel sensor data from the Single
board computer in XML format. The date and time are maintained on
the single board computer with battery backup and may be
re-programmed or data can be calibrated via the Internet. Data is
displayed over time on a continuously running strip chart within
the Internet browser's window.
[0076] An advantage of XML format is that it can be opened by any
conventional internet browser.
[0077] Connection for multiple receivers on a LAN and connection of
the LAN to a cable modem that connects to a PC console and to the
internet through a router and cable modem is shown in FIG. 9. In
this configuration PC console reads data on LAN from receivers and
sends it through router and cable to internet. Alternatively
instead of an ethernet LAN, a cellular phone can be used to send
the XML data from receivers to a PC console that then sends the
data through the cable modem to the internet, as shown in FIG.
10.
[0078] Data transmission can be scheduled, event triggered, or user
initiated. Scheduled is the simplest internet communications mode.
We have tested firmware that initiates a wireless modem connection
via a Kyocera 2235 cell phone, establishes an FTP connection, and
uploads data from the base station receiver. With the real-time
clock of the RCM2200, data can be delivered on an absolute schedule
(for example, upload at 5 PM every day), or on a regular interval
(upload every 48 hours).
[0079] In event-triggered mode, the base station can initiate the
uplink process if the collected data is outside of user-defined
critical thresholds. User-Initiated mode is especially helpful
during system installation, modification, and demonstration. As
described in the flowchart in FIG. 11, CPU is kept in a low power
state, monitoring the status of the "RING" line of the wireless
modem. If a user dials the number of the wireless modem, the RING
line is activated, the CPU recognizes the event, and initiates a
modem connection once the line is open. After the modem connection
is established with the ISP, the base station can either upload
data, or bring up a web server for the user to access. All three
modes can be provided in firmware.
[0080] To avoid power drain the wireless modem could be turned on
in scheduled windows of time. Hardware with substantially reduced
standby power requirement can also be used. For example wireless
modem SB555, requires only 1 to 2 mA of standby current.
[0081] Thus, the receivers are hard wired or wireless internet
appliances capable of operating as nodes on an Ethernet LAN.
Examples of wireless communications standards compatible with these
receivers include 802.11b (WIFI) and Bluetooth.
[0082] The system can include a docking station. The unmanned
vehicle is able to connect to the docking station for recharging
unmanned vehicle batteries or for transferring data to or from the
unmanned vehicle.
[0083] While several embodiments, together with modifications
thereof, have been described in detail herein and illustrated in
the accompanying drawings, it will be evident that various further
modifications are possible without departing from the scope of the
invention as claimed. Nothing in the above specification is
intended to limit the invention more narrowly than the appended
claims. The examples given are intended only to be illustrative
rather than exclusive.
* * * * *