Abstract:
The present invention discloses a novel method and apparatus for determining the position of a window glass in an aperture window as between one of two or more regions. Further, the present invention discloses a method and apparatus for determining the direction of travel of a window. The present invention senses the position and direction of travel of a window by measuring the amount of current in a motor that is suitable for moving the window as the window passes one or more elastic objects.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to power window regulators and more specifically to an apparatus and method for determining the position of a window. 
     BACKGROUND OF THE INVENTION 
     Power windows in automobiles are known to the art. A passenger in a vehicle is capable of raising or lowering a window by pressing a button generally located near a door release for an automobile. The movement of the window is generally controlled through a power window regulator. Power window regulators monitor the position of the glass from the closed position to the completely open position. Further, power window regulators may provide information regarding position of the glass to anti-squeeze controllers. An anti-squeeze controller may stop the movement of the glass if an obstruction is present between the glass and an upper seal. 
     Power window regulators known to the art fall into one of two types. The first type of power window regulator tracks the glass position continuously. The second type of power window regulator utilizes a sensor to determine if the glass has passed a predefined location usually close to the upper seal. Both types of power window regulators known to the art are subject to problems. For example, the type of power window regulator that tracks the glass position continuously is subject to numerous corrections. Over time, the numerous corrections that are required may lead to serious discrepancies between the actual glass position and the computed glass position. Also, the continuous glass position tracker type of power window regular renders more information than is necessary for typical anti-squeeze controllers. 
     The power window regulators that utilize a sensor to determine if the glass has passed a defined point is superior than the continuous tracking type, however it is limited by the high price of the item. With the defined point type of power window regulator, the travel path that the glass follows is divided into two regions or states. In the first state, the glass may encounter an obstruction in the path and the movement of the glass may be adjusted accordingly. In the second state, usually one millimeter from the upper seal, the glass may not encounter an obstruction. As stated, power window regulators are costly as a result of requiring a sensor and wires that communicate sensor data to a microcontroller. 
     It would be advantageous if a power window regulator existed that has the benefits of a two-state position type with regards to ease in use and reliability that may be utilized with anti-squeeze controllers without a requirement of an actual sensor and wires. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a novel method and apparatus for sensing whether glass has passed a boundary between the two-state space in which it travels along with the direction of travel by modifying a physical parameter of the motor during operation. Further, the present invention is capable of determining the direction of travel of the window glass without requiring a separate sensor and wires. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The numerous objects and advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
     FIG. 1 depicts a two-state position type power window regulator of the prior art; 
     FIG. 2 depicts an exemplary embodiment of the virtual sensor for window position of the present invention; 
     FIG. 3 displays the two regions and areas where the motor current may change according to an exemplary embodiment of the present invention; 
     FIG. 4 depicts a flow chart representing an exemplary process of the present invention; and 
     FIG. 5 is a block diagram of a computer based control system suitable for use with the virtual sensor system of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a power window regulator  100  of the prior art is shown. Typically, a section of a door  110  of an automobile has a window  120 . The window  120  is generally manufactured from some type of window glass including glass, plastic, or some type of composite of glass and plastic. Generally, the window glass may be raised to the top of the door and lowered into a cross-section of the door  110  to allow air from outside of the automobile to flow inside the automobile. The power window regulator of the prior art includes a sensor  130 , a controller  140 , and wires  150  connecting the sensor to the controller  140 . 
     Referring now to FIG. 2, an exemplary embodiment of the virtual sensor  200  of the present invention is disclosed. In an embodiment of the present invention, the virtual sensor  200  does not require a separate sensor and wires. The virtual sensor  200  comprises a motor  205  for moving the window glass  210 , a controller  250 , and at least one elastic object  230  placed in the path of the window glass  210 . 
     When the window glass  210  travels either upward or downward, it may pass one or more elastic objects  230 . Extra work may be required for the motor  205  when the window glass  210  is traveling upward and it passes an elastic object  230 . Less work may be required when the window glass  210  is traveling downward and it passes an elastic object  230 . The amount of work for the motor  205  may affect the amount of current necessary for the motor  205  to function properly. For example, when the window glass  210  is traveling upward and passes an elastic object  230 , the current in the motor  205  may increase. 
     In order to measure the current in the motor  205 , an ammeter  240  is connected to the motor. Depending upon the real-time current in the motor  205  and the change in current in the motor  205 , the controller  250  of the present invention may determine whether the window glass  205  is located in an obstacle region or an obstacle-free region. Further, the controller  250  may also calculate the direction of travel of the window glass  205 . 
     In order to utilize the present invention with anti-squeeze controllers, several elastic objects  230  may be required. If only one elastic object  230  is used, then the controller may not be able to distinguish whether a window glass is passing an elastic object from an obstacle in the path. For example, if an obstacle is within the path of the window glass  210 , then an increase in the current in the motor  205  may occur. An increase in the current may also occur if the window glass  210  is moving upward and passes an elastic object  230 . In order to distinguish between the two situations, several elastic objects  230  are placed along the path, each elastic object  230  containing a force of less than the  100  Newton mandate for an anti-squeeze controller. 
     Referring to FIG. 3, an example  300  of the adjustment in the amount of current that is required by the motor as a window glass  305  passes several elastic objects. The location of the top of the window glass  305  determines the area and region. In the obstacle-free region  310 , the anti-squeeze controller may be disengaged. When the top of the window glass  305  is located within the obstacle region  320 , an anti-squeeze controller may be utilized and engaged. A controller (not shown) determines what region the window glass is located in by measuring the current in the motor. For example, when the top of the window glass  305  is located within the lowest area  330 , the current in the motor may be a fixed value of x milliamperes. As the window glass  305  passes another elastic object and passes into a middle area  340 , the current may be x+10 milliamperes. When the window glass  305  passes into an upper area  350 , the current in the motor may be x+20 milliamperes. At this current level, the controller may be aware that the top of the window glass  305  is located in the obstacle-free region  310 , thus the anti-squeeze controller may be disengaged. However, when the current level is less than or equal to x+10 milliamperes, the controller may be aware that the window glass  305  is located within the obstacle region  320 . 
     In FIG. 4, an exemplary process  400  for virtually sensing the direction of travel of a window glass and position is described. The process  400  may begin when the window glass begins to move  405  typically by a passenger pressing a switch. As the window glass moves, it may pass an elastic object  410 . When the window glass passes an elastic object, a change in the motor current may take place  415 . 
     The controller of the present invention may determine whether the current increased or decreased when the window glass passed an elastic object  420 . If the current decreased, then the controller may be aware that the window glass is traveling downward  425 . The window glass may continue to travel downward until it first reaches the bottom or is stopped by a passenger or user  430 . If the controller notices an increase in current, then the controller may be aware that the window glass is traveling upward  435 . 
     Depending upon the amount of current increase  440 , the controller of the present invention may determine whether an obstacle is located in the path or if the window glass is approaching the upper seal of the window. For example, if a large current surge is detected, then an obstacle is in the path  450 . However, if there is a steady increase in current, then the window glass is close to the upper seal  445 . Once a particular amount of current is detected by the controller, then the top of the window glass has reached the obstacle-free region  310  as shown in FIG.  3 . 
     Referring generally to FIGS. 2-4, exemplary embodiments of the present invention include an elastic object. Generally, the elastic object may provide a resistive force to the window glass when the window glass is traveling upward, yet provide an impelling force to the window glass when the window glass is traveling downward. Examples of elastic objects include a spring, rubber, stretchable rope, and roughened patches. It should be understood that the list of elastic objects is not exclusive and other types of elastic objects may be utilized with the present invention without departing from the scope and spirit of the present invention. 
     Referring now to FIG. 5, a hardware system in accordance with the present invention is shown. The hardware system shown in FIG. 5 is generally representative of the hardware architecture of a controller embodiment of the present invention. Computer system  500  may be configured to implement one or more subsystems of the virtual sensor system  200  of FIG. 2, for example, as an embodiment of controller  250 . Central processor  502  includes a central processing unit such as a microprocessor or microcontroller for executing programs, performing data manipulations and controlling the tasks of computer system  500 . 
     Other components of computer system  500  include main memory  504 , and auxiliary memory  506 . Main memory  504  provides storage of instructions and data for programs executing on a central processor  502 . Main memory  504  is typically semiconductor based memory such as dynamic random access memory (DRAM) and or static random access memory (SRAM). Auxiliary memory  506  provides storage of instructions and data that are loaded into the main memory  504  before execution. Auxiliary memory  506  may include may include semiconductor-based memory such as read-only memory (ROM), programmable read-only memory (PROM) erasable programmable read-only memory (EPROM), electrically erasable read-only memory (EEPROM), or flash memory (block oriented memory similar to EEPROM). Other varieties of memory devices are contemplated as well. 
     Computer system  500  may further include an input/output (I/O) system  516  for connecting to one or more I/O devices. Input/output system  516  may comprise one or more controllers or adapters for providing interface functions between one or more of I/O devices  518 - 522 . Input/output system  516  and I/O devices  518 - 522  may provide or receive analog or digital signals for communication between computer system  500  of the present invention and external devices, networks, or information sources. 
     It is believed that the present invention and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.