Window Glass Position Control for Frameless Convertible Seals
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Solution Overview
Problem
In frameless window systems of convertible cars, existing methods fail to accurately estimate and adjust the short drop distance of vehicle window glass due to cable slack and temperature variations, leading to inaccuracies in position estimation and potential damage to the seal or glass.
Innovation Solution
A method that determines the actual movement of the window glass relative to the motor movement, estimates position lag based on motor and glass movement, and ambient temperature, and applies corrections to the short drop distance, accounting for varying cable stiffness over temperature and lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the window glass is lowered by a larger distance to ensure seal engagement, then the seal engagement is improved, but the risk of seal damage and glass damage increases
Solution Approach 1:
The system dynamically adjusts the short drop distance parameter based on temperature conditions. At lower temperatures, the cable is stiffer and requires a larger short drop distance to ensure proper seal engagement. At higher temperatures, the cable is more flexible and requires a smaller short drop distance to prevent seal damage. This parameter adaptation resolves the contradiction by optimizing the drop distance for each temperature condition.
Solution Approach 2:
The invention implements dynamic adjustment of the window glass positioning system based on real-time temperature feedback. The ECU continuously monitors temperature and adjusts the motor stopping position accordingly, transforming a static system into a dynamic one that adapts to changing cable stiffness conditions, thereby preventing both insufficient engagement and excessive damage risk.
2Object-affected harmful factors
If the window glass is lowered by a smaller distance to prevent seal damage, then the seal safety is improved, but the seal engagement reliability deteriorates
Solution Approach 1:
The system changes the short drop distance parameter based on temperature-induced cable stiffness variations. When the temperature is high and the cable is flexible, a smaller short drop distance prevents seal damage while still ensuring adequate engagement. When the temperature is low and the cable is stiff, a larger short drop distance ensures proper engagement without causing damage.
Solution Approach 2:
The invention creates a dynamic control system that adjusts the window glass positioning in real-time based on temperature conditions. The ECU modifies the motor stopping position dynamically, allowing the system to prevent seal damage under normal conditions while ensuring reliable engagement when cable stiffness increases due to low temperature.
3Reliability
If the short drop distance is increased to account for cable stiffness at low temperature, then the seal engagement is improved, but the position estimation accuracy deteriorates due to position lag
Solution Approach 1:
The system implements feedback control by continuously monitoring the actual window glass position and comparing it with the expected position based on motor rotations. The ECU calculates the position lag and adjusts the short drop distance accordingly, ensuring that the window glass reaches the correct position despite cable slack and stiffness variations. This feedback mechanism maintains both seal engagement reliability and position estimation accuracy.
Solution Approach 2:
The invention performs preliminary position correction by calculating the expected position lag based on temperature and cable stiffness characteristics before executing the short drop operation. The ECU pre-adjusts the motor stopping position to compensate for the anticipated position lag, ensuring that the window glass reaches the correct final position even with increased drop distance.
4Measurement precision
If the short drop distance is decreased to improve position estimation accuracy, then the position lag is reduced, but the seal engagement reliability deteriorates
Solution Approach 1:
The system uses feedback control to determine the optimal short drop distance based on actual position measurements. The ECU monitors the relationship between motor rotations and glass position, calculates the position lag, and adjusts the short drop distance to achieve both accurate position estimation and reliable seal engagement. This feedback loop allows the system to optimize both parameters simultaneously.
Solution Approach 2:
The invention performs preliminary calculation of the required short drop distance based on temperature and cable stiffness characteristics before executing the window lowering operation. By pre-determining the optimal drop distance, the system ensures both accurate position estimation and reliable seal engagement without needing to use a fixed conservative value.
5Device complexity
If a fixed short drop distance is used, then the system simplicity is maintained, but the adaptability to temperature variations deteriorates
Solution Approach 1:
The system changes the short drop distance parameter based on temperature conditions, implementing adaptability without significant complexity increase. The ECU stores pre-calculated short drop distance values for different temperature ranges and selects the appropriate value based on current temperature sensor readings, providing temperature adaptation through simple parameter switching.
Solution Approach 2:
The invention transforms the static fixed drop distance system into a dynamic adaptive system by introducing temperature-based adjustment. The ECU continuously monitors temperature and modifies the short drop distance accordingly, enabling the system to adapt to varying cable stiffness conditions while maintaining relatively simple control logic through lookup tables or simple calculation formulas.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method accurately corrects position lag, ensuring the window glass reaches the required position without damaging the seal or glass, meeting safety regulations and user comfort by eliminating inaccuracies in position estimation.
Implementation Method 1
the cable stiffness varies with temperature and lifetime, the position lag of the window glass is estimated accurately
Data Source
AI summary
A method for controlling movement of a window glass (12) in a vehicle using an electric motor (26) associated with a drive mechanism (1,2,3,4) through a cable (50), said method comprising the steps: determining an actual position (X2) of the window glass (12) based on the movement of the motor (26), determining a cable stiffness (S2), determining a position lag (400) of the window glass (12) based on the determined actual position (X2) of the window glass (12), a predetermined position (Z2) of the window glass (12) and the cable stiffness (S2); and continuously correcting the position of the window glass (12) based on the determined position lag (400).