This invention relates to a wayside sensor for railroads. More particularly this invention relates to a system for the reading of a sensor, processing the sensor output data and communicating the data in a wireless manner through the use of a power scavenging module.
Wayside sensors for railroad operations perform a variety of functions. Because wires must be run to each sensor for communication and electrical power, this results in significant installation costs and maintenance costs as well as reliability concerns.
Accordingly, there is a need in the art to provide a more effective method and system for wireless rail sensing systems specifically augmented by use of a localized power generation system.
In accordance with one embodiment of the present invention, a system for generating local power on railroad is provided. In this embodiment, the system includes a power scavenging module and a power utilizing module. The power scavenging module is configured to convert an excitation of a rail into electrical power. The power utilizing module is powered by the electrical power and is configured to detect a predetermined characteristic in relation to the rail or a train moving on the rail or an environment of the railroad and to communicate data in relation to the predetermined characteristic.
In accordance with another embodiment of the invention, a method is provided for generating local power on railroad. The method includes generating power from an excitation of a rail and energizing a power utilizing module using the power to detect a predetermined characteristic in relation to the rail or a train moving on the rail or an environment of the railroad and communicate data in relation to the predetermined characteristic.
According to one embodiment of the invention as described in
In one embodiment of the invention, the power utilizing module is the sensor module 14 that senses various operational parameters in relation to integrity of the rail and the train. In another embodiment of the invention, the power utilizing module is the signal conditioning module 16 that receives the output signals from the sensor module 14 and then converts these signals into digital form for further analysis and storage. In yet another embodiment of the invention, the power utilizing module is the output module 18 that receives conditioned signals from the signal conditioning module 16 and then communicates the resulting data to a control unit. Each of these elements—the power scavenging module 12, the sensor module 14, the signal conditioning module 16 and the output module 18 will be described in more detail below.
In one embodiment of the invention, the power producing piezoelectric transducer 88 is attached to the rail 28 of
Technical details of piezoelectric transducer 88 are known to persons skilled in the art and the specifics are not disclosed herein. Different embodiments of the railroad signaling system 10 of the present invention are herein described. However, it should be understood that the different modes for carrying out the invention hereinafter described are offered by way of illustration and not by the way of limitation. It is intended that the scope of the invention include all modifications that incorporate its principal design features.
The mechanical, electrical, physical and other properties of a particular piezoelectric transducer 88 determine the amount of electrical charge that is generated in response to a given applied force. The polarity of the generated charge on the other hand depends on whether the element is under compression or tension as a result of the externally applied force. The amount of electrical charge generated and the impedance of the external system that uses the power affect the voltages developed at the contacts, leads and nodes of the power scavenging module 12.
Functionally, in other embodiments of the invention, the stressing of the piezoelectric transducer 88 is done by subjecting the piezoelectric transducer 88 to a force or a stress or a strain in a single, multiple or other impulsive manner or in a cyclical or other repetitive manner. This is done either at a constant frequency or any other frequency or range of frequencies found to be desirable. If efficiency of energy harvesting device depends upon resonant quality factor that may vary with ambient temperature, a temperature compensated flexural mode structure may be incorporated to retain a high quality factor independent of temperature.
In this embodiment of the invention, the piezoelectric transducer 88 is configured based on a cantilever design and specifically a temperature compensated flexural mode structure maximizes the efficiency of the cantilever design. Moreover, the piezoelectric transducer 88 is designed to function near its resonance mode by appropriately choosing the dimensions. In a resonant state, the mechanical energy applied on the piezoelectric transducer 88 is transformed very efficiently into electrical energy. The resonance frequency varies as a function of a number of properties of the piezoelectric transducer 88 e.g., the size, shape, density and other physical parameters. The factors affecting resonance also include the constituent makeup, for example, the basic crystal constituents and the various additives used to provide and vary the piezoelectric properties of the crystal or crystals being employed.
Operationally, in yet another embodiment of the invention, the piezoelectric transducer 88 is made of materials that include thin polymer films, single crystal materials, or other piezoelectric element structures. These materials are used to form structures that are easily excited from a vibration input. This input may be a single discrete frequency, a combination of frequencies, or broadband vibration with a very large number of frequencies. The shape, size, density and other physical parameters of the materials and geometry of the structure have a direct impact on the efficiency of the piezoelectric structure to convert mechanical energy into electrical energy. These parameters are chosen to design the most efficient system obtainable.
In other embodiments of the invention, other systems such as hydraulic transducers, electromagnetic transducers and other types of transducers are considered for different alternative configurations of the power scavenging module 12 based on operational parameters such as ‘performance’ as measured in terms of power output, ‘cost’, ‘ease of installation’, ‘environmental impact’, ‘reliability’ etc. Various types of power scavenging modules produce different amounts of voltage and current. Various internal and external parameters are used to match the internal impedance of the power scavenging module 12 with the external impedance of the power utilizing modules like the sensor module 14, the signal conditioning module 16 or the output module 18. In an ‘impedance-matched’ state, the overall flexibility and performance of the railroad signaling system 10 is improved.
Referring to
In another embodiment of the invention, the input excitation to the transducer 44 in
Referring back to
In one embodiment, the regulator 98 is a shunt-type voltage regulator. A shunt regulator using a zener diode is the simplest and least expensive alternative. Shunt regulators keep the voltage across them to a maximum constant value, when a very low current is allowed to flow through it. In an alternative embodiment of the invention, a series regulator is used in the power conditioning circuit 46. The series regulator employs an impedance in series to drop any extra voltage between the generator and the impedance itself. Both the series and the shunt regulators are dissipative in nature and they both operate in step down mode. In another embodiment of the invention, a switching regulator is used in the power conditioning circuit 46, when the power generated is much higher than required. Switching regulators employ a switching element in their power regulating circuit and they operate in both step up and step down modes. Switching regulators need a very low current to maintain a high constant input voltage. Moreover, they need over-voltage protection in the form of a low current zener diode.
Referring to
There are various types of batteries 102 available. The factors to be considered while selecting a battery for the power storage system 48 are capacity, leakage current and number of charge-discharge cycles possible during the lifetime of the battery. Capacity of a battery is decided based on the load current, as the maximum current that is drawn depends on the ‘Ampere-hour’ rating of the battery and the charging current available from the power generator e.g., the power scavenging module 12 in the case of this embodiment of the invention. ‘Leakage current of a battery’ determines how much of electrical energy is lost from the battery and whether the battery will remain in a charged state for considerably long time. The battery used in this embodiment is a Lithium-ion Battery. The advantage of using such batteries is their high capacity and low leakage. That ensures that the voltage rarely falls below the required level and hence there is low startup time.
Referring to
The technical details of sensor module 14 and the sensing process therein are known to persons skilled in the art and specifics are not disclosed herein. The different embodiments and modes of sensing contemplated for the sensor module 14 of the present invention are herein described. It should be understood that the invention is not limited to the above-described configuration of the sensor module 14. The best mode for carrying out the invention hereinafter described is offered by way of illustration and not by the way of limitation. It is intended that the scope of the invention include all modifications that incorporate its principal design features.
In another embodiment of the invention, the sensor module 14 may include sensing systems to sense the status of a local signal or a visual signal. In yet another embodiment of the invention, sensor module 14 may include sensing systems to sense the position of a gate or a switch. In another embodiment of the invention, the sensor module 14 may include sensing systems to senses environmental characteristics such as wind speed, rainfall, snowfall, earthquake, landslide, temperature, barometric pressure, humidity etc.
Referring to
Another element of the circuitry 15 as illustrated in
The invention is not limited to the above-described configuration of the controller 22. In other embodiments of the invention, the controller 22 includes other solid-state equipments, relays, microprocessors, software, hardware, firmware, etc. or combinations thereof. All the read-out logic circuits in the system 10 also communicate with the controller 22 and the controller 22 in turn activates appropriate fail-time or warning alerts if the threshold level of an excitation from the broken rail detector 52 or the occupancy detector 54 or the train characteristics detector 56 is exceeded. The command signals issued by controller 22 take the form of simple go/no-go decisions wherein proper and improper performances are differentiated. Alternatively, more robust information is developed depending upon the type of situation being monitored, the sophistication of the sensor involved and logic performed by controller 22. For example, a history of field or performance data is recorded with future performance being predicted on the basis of the data trend. For audio performance data, the information includes volume, frequency, and pattern of sound verses time. For visual performance data, the information includes wavelength, visual images, intensity and pattern of light verses time. One should appreciate that the information stored by the controller 22 is directly responsive to known failure modes and performance characteristics of the particular type of railroad situation being monitored.
Referring to
An alternative to the embodiment described above is the use of a remote control unit 26 to control the operations of the railroad signaling system 10 remotely. The remote control unit 26 typically includes and makes use of access to the Internet or other wide area information networks. The receiver 72 of the output module 18, in this embodiment, receives communication signals from the controller 22 or from the remote control unit 26 or from the command control circuit (not shown) or from the wayside bungalow (not shown). In the same manner, the output module 18, in this embodiment communicates with the remote control unit 26. Functionally, the remote control unit 26 includes a microcontroller, such as a computerized data processor or an analog micro controller that receives the communication signals from the output module 18.
In an alternative embodiment, the remote control unit 26 includes a transmitter (not shown) and a remote receiver (not shown). The transmitter and the receiver can communicate in one or more of wireless, landline and fiber optic communication modes. Corresponding units housed in the output module 18 for two-way communication are the receiver 72 and the transmitter 66. The readiness of railroad signaling system 10 throughout the network is easily and automatically monitored by the remote control unit 26. In another embodiment of the invention, the remote control unit 26 has an additional database to store various operational and field maintenance data in relation to various components, subsystems of the railroad signaling system 10. For instance, data regarding the make, model, location, installation date, service history etc. of each component or each subsystem throughout the network are maintained in the database. Similar communication in relation to operation of the various components or subsystems of the railroad signaling system 10, such as the power scavenging module 12, the sensor module 14, the signal conditioning module 16 or the output module 18 is transmitted from the remote control unit 26 to the railroad signaling system controller 22 via the output module 18.
In yet another embodiment of the invention, the remote control unit 26 includes communication equipments located on a passing train, so that communication signals are conveyed between the remote control unit 26 and the output module 18 using a transmitter or a receiver positioned in the train. In yet another alternative embodiment, remote control unit 26 communicates with a remotely located operations control center (not shown) so that appropriate warnings are provided to trains moving on the rail line regarding a breakage in the rails or a malfunction of a component or a subsystem. Approaching trains are signaled to stop or to proceed at a slow speed in such eventualities. Data streams from other systems can also be incorporated in to the operations control center such as logistics and maintenance and diagnostics systems to create a higher level of decisioning for the rail companies. Decisions can be made concerning scheduling based on the data streams of maintenance records, location of the train, jobs in the queue, asset location etc. In another embodiment of the invention, decisions can be made based on integration of the data streams mentioned above with the data communicated by said output module. In similar manner, decisions for occupancy and consist can be optimized as well as alerts for security etc.
In an alternative embodiment, the system 10 also includes a data processing unit 24. Referring to
In other embodiments of the invention, analysis techniques performed by the data processing unit 24 involves numeric processing including computation of average values, peak values, time-to-maximum values, minimum values, time-to-minimum values, root mean square (RMS) values, cycle time, frequency, rise time, fall time, area values, integer values, pulse width, duty cycle, specified level time, differential pulse count of various sensing signals and their interpretation in various railroad related events such as acceleration or deceleration or stoppage of a train. In yet another embodiment of the data processing unit 24, algorithms are developed that relate a typical vibration signature of a train as detected by the train characteristics detector 56 and the power output of the power scavenging module 12 to other railroad related events such as a train stopping, accelerating, idling etc. In the event when the vibration signature of a train changes, it is possible to use the power scavenging module 12 and the train characteristics detector 56 in tandem to detect a possibility of a breakage in the rails. In such an event, the data processing unit 24 analyzes the data and communicates with the controller 22 via the remote control unit 26 to activate an appropriate warning signal switch. It is also be possible to compare vibration signatures of a train from both the rails and identify a breakage in the rails by analyzing the difference between the two signals from two different rails.
The invention is not limited to the above-described stand-alone configuration of the railroad signaling system 10. In another embodiment of the invention, the railroad signaling system 10 may be configured specifically for on-site use and it may be packaged in a hollow tie located in a rail-bed.
The overall operation of the system 10 is illustrated in
The transducers and the power storage system together ensure that there is sufficient power available all the time to operate all the other modules of the railroad signaling system 10. This way, drawing power either directly from the transducers or from the power storage system, the sensor module 14 is activated for sensing various operational parameters of passing trains, of the rails and a number of environmental characteristics as in step 168. More specifically, sensing operational parameters includes sensing any broken rail as in step 172, sensing block occupancy as in step 174 and sensing train characteristics as in step 176. In another embodiment of the invention, sensing operational parameters includes sensing status of a local signal or a visual signal. In yet another embodiment of the invention, sensing operational parameters includes sensing position of a gate or a switch. In another embodiment of the invention, sensing operational parameters includes sensing environmental characteristics such as wind speed, rainfall, snowfall, earthquake, landslide, temperature, barometric pressure, humidity etc. The output signals from the sensor module are next conditioned as in step 178 for further analysis and storage. Typically, the conditioning of the signals takes place by conversion of the analog output signals from the sensor modules into digital form.
Referring back to
On the other hand, the operation of the output module further includes communicating with a remote control unit as in step 184. The output module communicates data related to all operational parameters to the remote control unit and receives command signals from the remote control unit and then passes that on to the controller. The controller processes the command signals to control and monitor various functions of the railroad signaling system 10. The communication between the output module and the remote control unit, as in step 184, takes place via landline or wireless means. The remote control unit also communicates with a data processing unit. The data processing unit processes various operational data related to the train and the rail as in step 188. Processing of the operational data includes processing train signatures as in step 192 and processing various statistical data related to the operation of the train and the rail as in step 194.
In essence, the different embodiments described above make this invention a self-powered, flexible, surface mountable, small, lightweight, cost effective, mass producible system. All the subcomponents are typically housed in a hollow railroad tie and can be rapidly deployed in the rail bed eliminating the need of any separate bungalows or AC line power.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.