Patent Grant
8615927
The present teachings relate to an obstacle detection system using radio frequency identification tags, such as for preventing contact with an obstacle when closing a vehicle window, and a method for detecting an obstacle between two components to prevent contact with the obstacle.
Modern automotive vehicles are frequently equipped with power windows, power doors, power liftgates, and other automatically openable and closable closure panels. For example, certain power windows are referred to as “express up” windows. These windows are raised by a motor in response to depression of a button. The button can be released after an initial depression, and the window will continue to rise to close a window opening. These systems are usually configured to stop power to the motor if the window contacts an obstacle in the path of window travel during the closure.
An obstacle detection system is provided that prevents contact of a movable component with an obstacle. The system includes a first component and a second component. A motor is operatively connected to both the second component and a power source. The motor is configured to move the second component toward the first component when the motor is powered by the power source. Radio frequency identification tags (RFIDs) are connected to one of the first component and the second component. A controller is operatively connected to the motor and has a transmitter operatively connected to the other of the first component and the second component. The transmitter is operable to create a magnetic field between the first component and the second component. Each of the RFIDs is operable to provide a respective signal in response to the field. A receiver is configured to receive the respective signals. The controller is configured to modify power delivery from the power source to the motor when the respective signals received by the receiver change due to at least a portion of the magnetic field being at least partially blocked or attenuated.
In one embodiment, the first component is a weather seal on a vehicle door frame, and the second component is the door window movable toward the weather seal.
The RFIDs may be configured such that the respective signals provided by the RFIDs are digitally encoded with a predetermined waveform or other characteristic. The controller may be configured to determine whether the respective signals received by the receiver have the predetermined waveform or other characteristic, and to disregard any signals received by the receiver that do not have the predetermined waveform or other characteristic when determining whether the respective signals received by the receiver have changed. Such encoding of the RFID signals would enable the controller to differentiate between reflected signals or “noise” received by the receiver from signals actually emanating from the RFIDs, as only signals actually emanating from the RFIDs would have the predetermined waveform or other characteristic. The controller would thus be able to determine with greater accuracy whether signals received from the RFIDs have changed.
A method of detecting an obstacle between a first component and a second component movable by a motor toward the first component includes modifying power to the motor to modify movement of the second component when signals emitted by radio frequency identification tags (RFIDs) mounted to the first component change due to the field being at least partially blocked or attenuated by the obstacle. Stopping the second component when the signals emitted change prevents the second component from contacting the obstacle.
The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.
Referring to the drawings, wherein like reference numbers refer to like components throughout the several views,
The window assembly 12 is a power window assembly, as an electric motor 26 is powered by a power source 28 to raise and lower the window 16. An operator input device, such as a depressible button 30 is mounted to the door 10. When depressed, the button 30 establishes electrical power flow from a power source 28 to an electric motor 26 that is connected to the window 16 to raise and lower the window 16. For example, the power source 28 may be a vehicle battery located in a vehicle engine compartment and connected to the door 10 by electrical wiring. Alternately, an optional power source 29 within a controller 42 (described herein) may be used. The power source 28 may be remote from the door 10. Various types of operator input devices are known in the art, including toggle buttons and buttons with an up position and a down position. These operator input devices may or may not be located on the door assembly 10, may be located at some other location in the vehicle, or may be a device used to remotely operate the window assembly 12.
A vehicle driver or passenger may select to depress the button 30 to cause the motor 26 to be powered by the power source 28 to move the window 16 toward the weather seal 20. The obstacle detection system 14 prevents the window 16 from contacting an obstacle 32 located between the window 16 and the weather seal 20 while the window 16 is being raised. A representative obstacle 32 is shown in phantom in
The obstacle detection system 14 includes a plurality of radio frequency identification tags (RFIDs) 34 connected to the weather seal 20. The RFIDs 34 may be embedded in the weather seal 20 along a periphery 36 of the weather seal 20. The RFIDs 34 may be a string of discrete RFIDs each of which is only microns in length. RFIDs of such a small dimension may enable coextrusion of the RFIDs with the weather seal 20.
The weather seal 20 of
The obstacle detection system 14 also includes a transmission conductor 40 of wire or other metallic strip secured to the perimeter 18 of the window 16. The conductor 40 may be adhered or otherwise secured to or embedded in the window 16. A controller 42 is operatively connected to the conductor 40, the motor 26 and the power source 28. The controller 42 has a processor 44 with a stored algorithm that causes the controller 42 to modify power from the power source 28 to turn off the motor 26, reduce output of the motor 26, pause the motor 26, or reverse the direction of the motor 26 when an obstacle 32 is detected. In other embodiments, the RFIDs 34 may be mounted to the window 16 and the transmission conductor 40 may be connected to the weather seal 20.
The controller 42 also includes a transmitter 46 that is operatively connected to the conductor 40 on the window 16. The transmitter 46 is operable to send electrical energy to the conductor 40 to create a field 48 between the window 16 and the weather seal 20. The field is represented by arrows 48, and extends outward from the conductor 40 along the entire length of the conductor 40.
Each of the RFIDs 34 is operable to provide a respective signal 50 in response to the field 48. The signal may be a digitally encoded radio wave with a unique waveform, frequency, or other identifying characteristic. However, the obstacle 32 blocks the field 48 from reaching some of the RFIDs 34. Those RFIDs 34 that are not exposed to the magnetic field 48 do not provide a signal 50.
In the embodiment shown, the RFIDs 34 are passive tags, that each have an antenna 52, shown in
The signals 50 are transmitted via the conductor 40 to a receiver 54 of the controller 42. The receiver 54 transmits data representative of the signals 50 received to the processor 44. The processor 44 compares the data representative of the signals 50 received to a stored array of data corresponding with a set of signals 50 received from the RFIDs 34 when no obstacle is present to block any of the field 48. The processor 44 repeatedly performs this comparison in small increments of time as the window 16 is being raised by the motor 26. When an obstacle is present, the number of signals 50 emanating from the RFIDs 34 and received by the receiver 54 is different than the number of signals represented by the stored array of data (i.e., the number of signals expected to be received from the RFIDs 34 when no obstacles are present). The controller 42 may be configured to determine whether the respective signals received by the receiver 54 have the predetermined waveform or other characteristic by comparing each signal received to the predetermined waveform or other characteristic. Signals that are reflected or radiated rather than directly emanate from the RFIDs 34 will have a phase difference or other identifiable difference from the encoded signals 50. Signals received that do not have the predetermined waveform or other characteristic are disregarded by the controller 42, and thus do not affect the determination of whether the respective signals actually emanating from the RFIDs 34 and received by the receiver 54 have changed. Such encoding of the RFID signals 50 would enable the controller 42 to differentiate between reflected signals or “noise” received by the receiver from signals 50 actually emanating from the RFIDs 34, as only signals 50 actually emanating from the RFIDs would have the predetermined waveform or other characteristic. The controller 42 would thus be able to determine with greater accuracy whether signals received from the RFIDs 34 have changed (i.e., are different from the stored array of data representative of the set of signals 50 received when no obstacle is present).
An obstruction may completely block some of the field or cause a portion of the field to be attenuated. Depending on the attenuation coefficient of the obstacle 32, a portion of the field 48 may be attenuated rather than completely blocked. The stored array of data in the controller 42 may allow the controller 42 to determine whether attenuation of the signals 50 has occurred, and whether the level of attenuation is indicative of the presence of an obstacle 32. The stored array of data may represent a predetermined level of attenuation that is allowable without causing the controller 42 to determine that the signals 50 have changed.
When the processor 44 determines from the comparison that the data representative of the signals 50 received is different than the stored array of data, the controller 42 sends a control signal to modify power supplied to the motor 26, thus stopping, pausing, slowing or reversing the motor 26. The control signal 42 may open a switch or otherwise disrupt power to the motor 26. Because the determination made by the processor 44 can be made almost instantaneously when an obstacle 32 first enters the space between the window 16 and the weather seal 20 and disrupts the field 48, the motor 26 is stopped, paused, slowed, or reversed before the window 16 contacts the obstacle 32. The controller 42 is configured to cause the power source 28 to cease power to the motor 26 when the respective signals 50 received by the receiver 54 change due to at least a portion of the field 48 being blocked or attenuated by the obstacle 32.
In each of
While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.
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