Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1999-05-19
2001-08-14
Paladini, Albert W. (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C049S028000, C318S266000, C318S282000, C318S400260
Reexamination Certificate
active
06274947
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims benefit of priority of Japanese Patent Application No. Hei-10-138748 filed on May 20, 1998, the content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control device for a power window or a sliding roof for an automotive vehicle, more particularly to such a control device that includes a function to prevent a foreign object from being pinched or sandwiched between a window frame and a sliding window glass.
2. Description of Related Art
A control device of this kind is disclosed in JP-Y2-2553373, for example. In this control device, a rotational speed variation rate of a motor that actuates a power window is calculated and stored in a memory. A predictive rotational speed is determined from the stored speed variation rate and a preceding rotational speed. If a presently detected rotational speed is lower than the predictive rotational speed, it is determined that a foreign object is pinched or sandwiched between a window frame and a sliding glass that is traveling in a direction to close the window. When such pinching is detected, the window glass is lowered to open the window.
The rotational speed of the motor, however, is affected by not only pinching but also other factors such as a terminal voltage of the motor and ambient temperature. Accordingly, the conventional control device in which detection of pinching solely depends on the predictive motor speed and the detected motor speed is not able to eliminate influence of other factors. Therefore, accuracy of the pinching detection is not sufficiently high. It may be possible to enhance the detection accuracy by storing data showing relation between the motor speed and other external factors in a microcomputer and modifying the motor speed based on the stored data. However, there is a problem that the control circuit becomes complex and a program size becomes large.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-mentioned problem, and an object of the present invention is to provide an improved controller for a power window, which is able to detect accurately a situation where a foreign object is pinched or sandwiched between a window frame and an upwardly traveling window glass, eliminating influence of other factors. Another object of the present invention is to provide such a controller that accurately detects the pinching situation without increasing a controller size and a control program size. A further object of the present invention is to provide a method of controlling the power window operation in which the pinching situation is accurately detected.
A power window is driven by an electric motor controlled by a controller including a microcomputer. A power window stroke from a fully open position to a fully closed position is divided into plural measuring sections, and the window position is detected by a limit switch or by counting pulses indicating the window position. Preferably, the measuring sections are more finely divided as the window position approaches to the fully closed position, because the pinching situation (wherein some obstacles are pinched or sandwiched between an upper frame of the window and a sliding window glass) mostly occurs at a window position close to the fully closed position. Rotational speed V of the motor is detected by counting pulses fed from the motor to the controller. When the power window is operated in the closing direction, motor speed variation rates R are calculated several times in each measuring section based on the motor speed V. Also, a threshold value TH which is inversely proportional to the motor speed V is calculated.
A highest value Gn among variation rates R in each measuring section is selected as a representing variation rate in that measuring section n. The variation rate R is set as a positive value when the motor is decelerating, while it is set as a negative value when the motor is accelerating. In selecting the highest value Gn from among the variation rates R in each measuring section, the variation rates having a negative value are precluded. The controller also includes a function to detect external disturbances such as changes of a voltage supplied to the motor. The highest value Gn in each measuring section is not memorized when such disturbances are detected to eliminate influence of such disturbances in finding the pinching situation. Also, the highest value Gn is not memorized when the power window is not successfully closed due to occurrence of the pinching situation.
The highest value Gn representing the motor speed variation in each measuring section is memorized during a previous closing operation of the power window, and the memorized value Gn is used to adjust the threshold value TH during a following closing operation of the power window. That is, an adjusted threshold value TH′(n) in a given measuring section n is calculated according to a formula: TH′(n)=TH+Gn. The pinching situation is found out in each measuring section when the variation rate R becomes larger than the adjusted threshold value TH′(n), i.e., R>TH′(n). When the pinching situation is found, the motor is once stopped and then the power window is lowered to prevent further pinching. In addition, a maximum value Gmax among the values Gn is stored in a non-volatile memory to use it in place of the value Gn in adjusting the threshold value TH when no Gn is available in a previous window closing operation.
Thus, the pinching situation is detected without fail while eliminating the influence of the external disturbances. The function of pinching prevention is easily included in the controller without making the controller large in size and without substantially increasing a program size in the microcomputer. The motor speed variation rate R may be adjusted in lieu of the threshold value TH with the value Gn memorized in a previous window closing operation. The same results are obtained in this manner, too.
Other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiment described below with reference to the following drawings.
REFERENCES:
patent: 5404673 (1995-04-01), Takeda et al.
patent: 5530329 (1996-06-01), Shigematsu et al.
patent: 5650698 (1997-07-01), Ito et al.
patent: 5977732 (1999-11-01), Matsumoto
patent: 5983567 (1999-11-01), Mitsuda
patent: 6-123188 (1994-05-01), None
patent: 2553373 (1997-07-01), None
Denso Corporation
Paladini Albert W.
Pillsbury & Winthrop LLP
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