Abstract:
One aspect of the disclosed embodiment is a method and system for conserving battery life in a wireless access control system. This disclosed embodiment comprises a wireless access control system with a lock having an electronic controller and a piezo electronic driven locking mechanism. The electronic controller controls voltage to the piezo electronic locking mechanism. These and other features of the disclosed embodiment are discussed in the following detailed description of the disclosed embodiment.

Description:
RELATED APPLICATIONS  
       [0001]     The present application claims priority to the following applications: application Ser. No. 10/261,933, entitled “RF Channel Linking Method and System” filed Sep. 30, 2002; application Ser. No. 10/262,207, entitled “Energy Saving Motor-Driven Locking Subsystem” filed Sep. 30, 2002; application Ser. No. 10/262,509, entitled “Cardholder Interface for an Access Control System” filed Sep. 30, 2002; application Ser. No. 10/262,196, entitled “System Management Interface for Radio Frequency Access Control” filed Sep. 30, 2002; application Ser. No. 10/262,194 entitled “Power Management for Locking System” filed Sep. 30, 2002; application Ser. No. 10/262,507, entitled “General Access Control Features for a RF Access Control System” filed Sep. 30, 2002; application Ser. No. 10/262,077, entitled “RF Wireless Access Control for Locking System” filed Sep. 30, 2002; application Ser. No. 10/262,508, entitled “Maintenance/Trouble Signals for a RF Wireless Locking System” filed Sep. 30, 2002; application Ser. No. 10/262,249, entitled “RF Dynamic Channel Switching Method” filed Sep. 30, 2002, and U.S. Provisional Patent Application No. 60/537,922, entitled “Wireless Access Control System With Energy-Saving Piezo-Electric Locking” filed Jan. 20, 2004.  
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The preferred embodiments of the present invention relate to an RF access control system for controlling access to an access point. More specifically, the preferred embodiments of the present invention relate to a method and system for driving a motor of a motor-driven locking subsystem of an access control system in such a way as to save battery power of the motor-driven locking subsystem and ensure security by using a piezoelectric locking system.  
         [0003]     A wireless access control system may provide several advantages over a traditional, wire-based access control system. In a traditional, wired access control system, each access point, such as a door, for example, is equipped with a locking module to secure the access point. Each locking module is in turn directly wired to a remote access control module. The access control module is typically a database that compares a signal received from the locking module to a stored signal in the database in order to determine an access decision for that locking module. Once the access decision has been determined by the access control module, the decision is relayed to the locking module through the wired connection.  
         [0004]     The use of wired connections between the access control module and the locking module necessitates a large investment of time and expense in purchasing and installing the wires. For example, for larger installations, literally miles of wires must be purchased and installed. An access control system that minimizes the time and expense of the installation would be highly desirable.  
         [0005]     Additionally, wire-based systems are prone to reliability and security failures. For example, a wire may short out or be cut and the locking module connected to the access control module by the wire may no longer be under the control of the access control module. If a wire connection is cut or goes, the only alternative is to repair the faulty location (which may not be feasible) or run new wire all the way from the access control module to the locking module, thus incurring additional time and expense. Conversely, an access control system that provides several available communication channels between the locking module and the access control module so that if one communication channel is not usable, communication may proceed on one of the other communication channels, would also be highly desirable, especially if such an access control system did not add additional costs to install the additional communication channels.  
         [0006]     A wireless access system providing a wireless communication channel between the locking module and the access control module may provide many benefits over the standard, wire-based access control system. Such a wireless access system is typically less expensive to install and maintain due to the minimization of wire and the necessary installation time. Additionally, such a system is typically more secure because communication between the locking module and the access control module is more robust than a single wire.  
         [0007]     However, one difficulty often encountered in installing and maintaining such a wireless access system is providing power to the individual, remote locking modules. For example, such locking modules may be powered by battery, but standard locking modules for wire-based access control systems are typically quite wasteful of power, a commodity in short supply in wireless access systems. Consequently, a motor driving the locking mechanism of the locking module that is power efficient is highly desirable.  
         [0008]     Although motor driven locks typically use less energy than other types of locks (such as a solenoid driven latch, for example), motor driven locks still require a comparatively large draw of power, especially when powered by batteries. That is, driving the motor to lock and or unlock the latch mechanism still requires a great deal of energy. The large power draw drains the batteries at a fast rate, yielding a reduced number of times that a door with a motor driven locking mechanism may be locked/unlocked before the battery needs to be replaced or recharged.  
         [0009]     Consequently, a simple, cost effective battery powered locking system that provides for conserving energy in order to maximize battery life would be highly desirable.  
       BRIEF SUMMARY OF THE INVENTION  
       [0010]     One aspect of the disclosed embodiment is a method and system for conserving battery life in a wireless access control system. This disclosed embodiment comprises a wireless access control system with a lock having an electronic controller and a piezo electronic driven locking mechanism. The electronic controller drives the piezo electronic locking mechanism. These and other features of the disclosed embodiment are discussed in the following detailed description of the disclosed embodiment.  
     
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS  
       [0011]      FIG. 1  illustrates a block diagram of the components of a wireless access system according to a preferred embodiment of the present invention.  
         [0012]      FIG. 2  illustrates a block diagram of the components of an expanded wireless access system according to a preferred embodiment of the present invention.  
         [0013]      FIG. 3  illustrates a Wireless Access Point Module (WAPM) for the wireless access system of FIG. I according to a preferred embodiment of the present invention.  
         [0014]      FIG. 4  illustrates a WPIM for the wireless access system of  FIG. 1  according to a preferred embodiment of the present invention.  
         [0015]      FIG. 5  is a schematic block diagram of a piezo-electronic locking subsystem according to a preferred embodiment of the present invention.  
         [0016]      FIG. 6  illustrates a flowchart of the operation of the piezo-electronic locking subsystem of  FIG. 5 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     The present application is directed toward a portion of a wireless access system. Additional disclosure of the wireless access system may be found in the following applications which are hereby incorporated by reference in their entirety: application Ser. No. 10/261,933, entitled “RF Channel Linking Method and System” filed Sep. 30, 2002; application Ser. No. 10/262,207, entitled “Energy Saving Motor-Driven Locking Subsystem” filed Sep. 30, 2002; application Ser. No. 10/262,509, entitled “Cardholder Interface for an Access Control System” filed Sep. 30, 2002; application Ser. No. 10/262,196, entitled “System Management Interface for Radio Frequency Access Control” filed Sep. 30, 2002; application Ser. No. 10/262,194, entitled “Power Management for Locking System” filed Sep. 30, 2002; application Ser. No. 10/262,507, entitled “General Access Control Features for a RF Access Control System” filed Sep. 30, 2002; application Ser. No. 10/262,077, entitled “RF Wireless Access Control for Locking System” filed Sep. 30, 2002; application Ser. No. 10/262,508, entitled “Maintenance/Trouble Signals for a RF Wireless Locking System” filed Sep. 30, 2002; and application Ser. No. 10/262,249, entitled “RF Dynamic Channel Switching Method” filed Sep. 30, 2002.  
         [0018]      FIG. 1  illustrates a block diagram of the components of a wireless access system  100  according to a preferred embodiment of the present invention. The wireless access system  100  includes several components installed at one of two generalized locations, an access control panel location  102  and an access point location  103 . The access control panel location  102  includes an access control panel (ACP)  110  and a Wireless Panel Interface Module (WPIM)  120 . The access point location  103  includes a Wireless Access Point Module (WAPM)  130  and an access point  140 . The access control panel  110  communicates with the WPIM  120  through a bi-directional wired communication link  115 . The WPIM  120  communicates with the WAPM  130  through a bi-directional RF communication link  125 . The WAPM  130  communicates with the access point  140  through a bi-directional wired communication link  135 . The access point  140  is preferably a door or portal, but may be a container, secure location, or a device of some kind, for example.  
         [0019]     In operation, an access signal is read at the access point  140 . The access signal may be a signal from an access card, for example, a magnetic stripe or Wiegand access card. Alternatively, the access signal may be a biometric or a numeric sequence or some other access signal. The access signal is relayed from the access point  140  to the WAPM  130  through the wired communication link  135 . As further described below, the access point  140  may be integrated into the WAPM  130  to form a single component or may be a separate component wired to the WAPM  130 .  
         [0020]     Once the WAPM  130  receives the access signal from the access point  140 , the WAPM  130  transmits the access signal to the WPIM  120  over the RF communication link  125 . The WPIM  120  receives the access signal and relays the access signal to the ACP  110  over the wired communication link  115 .  
         [0021]      FIG. 2  illustrates a block diagram of the components of an expanded wireless access system  200  according to a preferred embodiment of the present invention. The expanded wireless access system  200  includes an ACP  210 , multiple wired communication links  220 ,  222  numbered 1 to N, multiple WPIMs  222 ,  252  numbered 1 to N, multiple RF communication links  230 ,  232 ,  260 ,  262  numbered 1 to K and 1 to J, and multiple WAPMs  240 ,  242 ,  270 ,  272  numbered 1 to K and 1 to J. The expanded wireless access system  200  is similar to the access system  100  of  FIG. 1 , and includes the same components, but has been expanded to include multiple access points, WAPMs, and WPIMs.  
         [0022]     In the expanded wireless access system  200 , a single ACP  210  communicates with a number N of WPIMs  222 ,  252  over a number N of wired communication links  220 ,  250 . That is, the ACP supports communication with and provides access decisions for plurality of WPIMs  222 ,  252 . Each WPIM  222 ,  252  may in turn support a plurality of WAPMs  240 ,  242 ,  270 ,  272  each WAPM positioned at a single access point. For example, WPIM #1 communicates with a number K of WAPMs  240 ,  242  over a number K of RF communication links  230 ,  232 . Additionally, WPIM #N communicates with a number J of WAPMs  270 ,  272  over a number J of RF communication links  260 ,  262 .  
         [0023]     In a preferred embodiment, the ACP  210  supports three WPIMs and each PIM can support up to six WAPMs. However, as more advanced and configurable systems are developed, the total numbers of WPIMs and WAPMs supported is expected to rise. Additionally, the N wired communication links  220 ,  250  are illustrated as the preferred embodiment of RS486 communication links. Alternatively, other well-known communication protocols may be employed.  
         [0024]      FIG. 3  illustrates a Wireless Access Point Module (WAPM)  300  for the wireless access system  100  of  FIG. 1  according to a preferred embodiment of the present invention. The WAPM  300  includes a housing  310 , indicators  320 , a wired communication link  330 , a RF communication link  332 , and an antenna  325 . The housing  310  includes a locking control circuit  340 , an access/monitoring processor  350 , a transceiver  360 , a power supply  370 , an override port  380 , and an access reader  390 . The indicators  320  may include one or both of an audio indicator  322  and a visual indicator  324 . An access point  301  is also shown in  FIG. 3 .  
         [0025]     The power supply  370  provides power to all of the other systems of the housing  310 , including the transceiver  360 , the locking control circuit  340 , and the access/monitoring processor  350 . The power supply  370  may be an internal battery or other internal type of power supply. Alternatively, an AC power supply may be employed. The transceiver  360  is coupled to the antenna  325  to allow signals to be sent and received from the housing  310  to an external point such as a WPIM through the RF communication link  332 . The locking control circuit  340  is coupled to the access point  301  and provides locking control signals to the access point  301  through the wired communication link  330 . Additionally, the locking control circuit  340  may receive feedback from the access point  301  through the wired communication link  330 , for example to verify that the access point is secured. The access reader  390  receives access signals such as from an integrated card reader or other access device, for example. The indicators  320  may provide a visual or audio indication, for example, of the state of the WAPM  300  or that an access signal has been read by the access reader  390 .  
         [0026]     In operation, an access signal may be received from the access reader  390 . The access signal is then relayed to the access/monitoring processor  350 . The access/monitoring processor  350  then sends the access signal to the transceiver  360 . The transceiver  360  transmits the access signal to WPIM  120  of  FIG. 1  that is interfaced to the ACP  110 . As further explained below, the ACP  110  includes a database of authorized access signals. If the access signal received from the WAPM  300  is determined by the ACP  110  to be a signal corresponding to an authorized user, a confirmation is transmitted from the ACP  110  to the WPIM  120  and then to the transceiver  360  of the WAPM  300 . The confirmation is relayed from the transceiver  360  to the access/monitoring processor  350 . The access/monitoring processor  350  then sends a locking control signal to the locking control unit  340 . When the locking control unit  340  receives the locking control signal, the locking control unit  340  activates the access point  301  through the wired communication link  330  to allow access. The indicators  320  may be a visual or audible signal that the housing  310  has read an access signal, transmitted the access signal to the remote access control panel, received a confirmation, or activated the locking member, for example.  
         [0027]     The WAPM  300  may include several variations. For example, the WAPM may be an Integrated Reader Lock (IRL), a Wireless Reader Interface (WRI), a Wireless Integrated Strike Interface (WISI), a Wireless Universal Strike Interface (WUSI), or a Wireless Portable Reader (WPR). The IRL includes an integrated access reader and lock. That is, the IRL is similar to  FIG. 3 , but includes the access point as part of the housing. The WRI is similar to the IRL, but does not include an integrated access reader and instead receives signals from a third party access reader. The WISI includes an integrated reader and lock and is mounted directly into the strike of the access point, such as a door, for example. The WUSI is similar to the WISI, but does not include an integrated reader and lock and may instead be connected to a third party reader and/or lock. The WPR is a portable reader that may be taken to a remote location and determine access decisions at the remote location, for example, for security checks or badging checks.  
         [0028]      FIG. 4  illustrates a WPIM  400  for the wireless access system  100  of  FIG. 1  according to a preferred embodiment of the present invention. The WPIM  400  includes a housing  410 , an antenna  465 , and indicators  420 . The housing  410  includes a data port  430 , a control processor  450 , a transceiver  460  and an ACP interface  470 .  FIG. 4  also shows an RF communication link  467 , a wired communication link  472 , and an ACP  480 .  
         [0029]     Power is typically supplied to the WPIM via an AC power supply or through the wired communication  472 . The transceiver  460  is coupled to the antenna  465  to allow signals to be sent and received from the housing  410  to an external point such as a WAPM through the RF communication link  467 . The ACP  480  is coupled to the WPIM  400  through the wired communication link  472 . The data port  430  is coupled to the control processor  450  to allow an external user such as a technician, for example, to interface with the control processor. The indicators  420  may provide a visual or audio indication, for example of the state of the WPIM  400  or that an access signal has been passed to the ACP  480  or an authorization passed to a WAPM  300 .  
         [0030]     In operation, the WPIM  400  receives access signals from the WAPM  300  through the antenna  465  and transceiver  460 . The WPIM relays the access signals to the ACP  480  for decision making. Once the access decision has been made, the ACP  480  transmits the access decision through the wired communication link  472  to the WPUM  400 . The WPIM  400  then transmits the access decision to the WAPM  300 .  
         [0031]     As mentioned above, the WPIM  400  includes a data port  430 . The data port  430  is preferably an RS485 port. The data port  430  may be used, for example, by an operator to connect a computer to the WPIM  400  to perform various tasks, such as configuring the WPIM  400 , for example. Some exemplary WPIM items for configuration include the transmission frequency for the communication link with the WAPM and the performance of the indicators  420 .  
         [0032]     Additionally, configuration information may be received by the data port  430  of the WPIM  400  and relayed to the WAPM  300  via the transceiver  460 . The configuration information that is received by the WAPM  300  may then by relayed to the access/monitoring processor  350  of the WAPM  300  for implementation at the WAPM  300 .  
         [0033]     The WPIM may include several variations including a panel interface module (PI) and a panel interface module expander (PIME). As mentioned above, a single PIM may communicate with multiple WAPMs. Additionally, the housing for the PIM is preferably constructed to allow additional PIM modules to be installed in the PIM housing to form the PIME. Because the PIME includes multiple PIM modules, the PIME may service more access points.  
         [0034]     The features of one of the preferred embodiments present a method and system for conserving battery life in an access control system. Thus, one aspect of a preferred embodiment of the present invention is an access system that employs a piezo electronic locking subsystem as further described below. The exemplary discussion below focuses on the use of the wireless access system  100  of  FIG. 1  configured to provide access through a door. Although the access point below is presented as a door, it is only one example of the possible access points.  
         [0035]      FIG. 5  is a schematic block diagram of a piezo-electronic locking subsystem  500  according to a preferred embodiment of the present invention. The piezo-electronic locking subsystem  500  includes an electronic control processor  510 , a piezo-electric lock  520 , a DC power supply  530 , a bolt  535 , and a latch  540 . An authorizing unit signal  501  is also shown. The DC power supply is preferably a battery, but any device for supplying DC power may be substituted.  
         [0036]     In operation, the electronic control processor  510  of the piezo-electronic locking subsystem  500  receives an authorizing unit signal  501 . The authorizing unit signal  501  may be received from the locking control unit  340  of  FIG. 3 , for example, in response to a user access decision. The electronic control processor  510  then sends a command to the piezo-electric lock  520  in response to the received authorizing unit signal  501 .  
         [0037]     The piezo-electric lock  520  preferably includes an internal piezo-electric element as well as a positional displacement amplifier. The piezo-electric element may be any element having a physical dimension that varies when an electric voltage is applied across the element, such as a piezo-electric crystal, for example. The positional displacement amplifier is preferably in cooperation with the piezo-electric element and serves to increase the displacement arising when a voltage is applied cross the piezo-electric element. For example, the positional displacement amplifier may increase the displacement generated by the piezo-electric element by a factor of 10. The positional displacement amplifier is preferably connected to and used to position the bolt  535 .  
         [0038]     The piezo-electric lock  520  is preferably configured so that the piezo-electric lock  520  is in a locked position when voltage is applied to the piezo-electric element. That is, voltage applied across the piezo-electric element causes the piezo-electric element&#39;s shape to change and the change in shape is amplified by the positional displacement amplifier which drives the bolt  535  closed. When no voltage is applied to the piezo-electric element, the bolt  535  is not displaced. Consequently, the piezo-electric lock is open when no voltage is applied.  
         [0039]     Alternatively, the polarity of the piezo-electric lock may be reversed so that the piezo-electric lock is in an open configuration when a voltage is applied and transitions to a locked configuration when no voltage is applied.  
         [0040]     When the DC power supply  530  receives the command from the electronic control processor  510  to initiate a locking operation, the DC power supply  530  is enabled to apply a voltage across the piezo-electric element. The applied voltage causes the bolt  535  to be displaced into the latch  540  consequently locking the piezo-electric lock and securing the door.  
         [0041]     To unlock the door, an authorizing unit signal  501  is sent to the electronic control processor  510 . The electronic control processor  510  then removes the voltage applied to the piezo-electric element in the piezo-electric lock  520 . Once the voltage is no longer supplied to the piezo-electric element, the piezo-electric element reverts to its original shape and the bolt  353  assumes an unlocked position.  
         [0042]      FIG. 6  illustrates a flowchart  600  of the operation of the piezo-electronic locking subsystem  500  of  FIG. 5 . The flowchart begins at step  610  when the piezo-electronic locking subsystem  500  is turned on. The flowchart then proceeds to step  620  and queries whether the door is currently locked. As mentioned above, the piezo-electric lock is preferably configured to assume a locked configuration when a voltage is applied to the lock. If the door is locked, the flowchart then proceeds to step  630 . At step  630 , the process queries whether an authorizing signal has been received by the piezo-electronic locking subsystem  500  in order to unlock or open the door. If no authorizing signal has been received, the process then proceeds back to step  620 . Conversely, if an authorization signal has been received, the process proceeds to step  640  and the voltage is removed from the piezo-electric element in order to unlock the bolt. The process then proceeds back to step  620 .  
         [0043]     Returning to step  620 , if the process determines that the door is unlocked, the process proceeds to step  650 . At step  650 , the process determines whether a pre-determined time limit has elapsed. That is, the piezo-electric lock is preferably configured to remain open only for a certain pre-determined time. After the predetermined time has lapsed, the piezo-electric lock preferably re-locks to secure the door. If the pre-determined time limit has elapsed at step  650 , then the process proceeds to step  670  and a voltage is applied to the piezo-electric lock in order to lock the door.  
         [0044]     If the pre-determined time limit has not elapsed at step  650 , then the process proceeds to step  660 . At step  660 , the process queries whether an authorization signal has been received to lock the door. If no locking signal has been received, the process proceeds back to step  620 . Conversely, if an authorization signal to lock the door has been received, the process proceeds to step  660  and the voltage is reapplied across the piezo-electric element in order to lock the door. The process then proceeds back to step  620 .  
         [0045]     While particular elements, embodiments and applications of the present invention have been shown and described, it is understood that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teaching. It is therefore contemplated by the appended claims to cover such modifications and incorporate those features that come within the spirit and scope of the invention.