Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
2000-06-16
2001-10-02
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C318S455000
Reexamination Certificate
active
06298295
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a method of detecting obstruction in the path of a moving closure, wherein a detection limit is set to identify obstructions at start-up.
Vehicle closures, such as windows, moonroofs, sunroofs, etc. are typically powered by a motor at the request of an operator closure switch. As the closure moves to close an opening in the vehicle cab, there may sometimes be an obstruction in the path of the closure. An obstruction, such as a passenger's arm, will increase the load on the motor closing the closure, or decrease the speed. Typically, a control system for the closure motor monitors a characteristic such as speed, power or torque, and identifies an obstruction should the monitored characteristic change more than a predetermined limit away from a predicted value.
Difficulties arise in setting the predicted value to correspond to the particular system dynamics for the closure in the vehicle. Further, other challenges, such as variations to the actual characteristic due to vibration, temperature, etc. may vary the monitored characteristic, for a reason other than obstruction.
To provide a more accurate indication of an obstruction, some systems have monitored the actual system response, and utilize that monitored system response as an indication of what the true predicted value should be. That is, some form of a “learn” cycle is utilized.
Closure systems typically monitor start-up changes. Typically, a start-up change would include a first upper peak, and then repeated decaying lower and upper peaks. However, a system that monitors start-up peaks, and utilizes the start-up peaks as “learned” expected value, will not always provide an accurate indication of an obstruction at start-up. That is, if an obstruction would give rise to a lower value than expected (such as a system monitoring speed) a lowered value at start-up might be seen as one of the valleys that follow the peak at start-up. Thus, there is the potential for missing an identification of an obstruction in a system which learns the system response and utilizes start-up values.
SUMMARY OF THE INVENTION
In a disclosed embodiment of this invention, an initial value is utilized to set a limit. The initial value is selected in a direction away from the change in the monitored characteristic which is expected due to an obstruction. Thus, in the case of speed, an initial upper value is utilized, and multiplied by a scaler to set a fixed limit for start-up. If the monitored value crosses this fixed limit, then an obstruction is indicated. By utilizing this first upper value, the system will not identify the expected decaying valleys as crossing a limit. The system will, however, also be able to distinguish between an obstruction during the start-up time and those expected valleys.
In a preferred embodiment, the scaler multiplied by the initial upper maximum peak is selected to be less than the ratio of the first valley divided by the first peak. That is, the scaler is selected to be somewhat less than 1. In this way, a limit is selected which will identify obstructions even at start-up. This limit can merge into a distinct limit or predicted value after a short start-up period, or could be utilized during the entire closure.
In a system monitoring power, it is the initial valley or minimum value which is utilized to select the limit. In such a case, the scaler is selected to be greater than 1, and also greater than the ratio of the maximum current value divided by the minimum current value.
Finally, the disclosed invention recognizes the effect of system hysteresis. This is a recognition that the system response at start-up will be different dependent on the previous movement of the window. If the previous movement was closing, typically the peaks and valleys tend to be more pronounced than if the previous movement was opening. The present invention thus may select different scaler values that can be utilized dependent on the last movement. The control will remember the last movement and select the appropriate scaler value to set the appropriate limit.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
REFERENCES:
patent: 4342379 (1982-08-01), Games et al.
patent: 5864104 (1999-01-01), Tawada et al.
Carlson & Gaskey & Olds
Meritor Light Vehicle Technology, LLC
Nguyen Tan
LandOfFree
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