Vehicle Closure Position Accuracy via Force-Displacement Correlation
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Solution Overview
Problem
Existing methods for position determination of motor-driven closure elements in vehicles, such as window-lifters and sliding roofs, suffer from inaccuracies and high system costs, particularly when using Hall sensors or commutator current ripple counting, and require frequent re-initialization which increases mechanical loading and costs.
Innovation Solution
A method and device that determine and store force-displacement reference and actual-value curves, calculate a correlation function, and correct position counter errors using the position offset value associated with the maximum of this function, allowing for precise position determination without the need to move the closure element to an end stop, using a single Hall sensor or commutator current ripple counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two Hall sensors are used for position determination, then position accuracy is improved, but system cost increases
Solution Approach 1:
The system uses feedback by continuously monitoring the force-displacement relationship during window movement and comparing it against the reference curve. The evaluator constantly adjusts the position counter status based on deviations detected through force measurements, creating a closed-loop correction system that maintains accuracy without requiring multiple sensors.
Solution Approach 2:
The invention replaces the mechanical/optical sensor-based position determination (Hall sensors) with a force-based electrical measurement system. By measuring the force required to move the window and comparing it to the reference force-displacement curve, the system determines position electrically rather than mechanically, reducing component count while maintaining accuracy.
2Measurement precision
If re-initialization is performed frequently, then position accuracy is maintained, but mechanical loading increases
Solution Approach 1:
The system implements continuous feedback during normal operation by monitoring the force-displacement relationship. Instead of periodically re-initializing to the mechanical stop, the evaluator continuously compares actual force measurements with the reference curve and adjusts the position counter in real-time, maintaining accuracy without mechanical re-initialization cycles.
Solution Approach 2:
The system performs self-correction by using the force measurements taken during normal window operation to detect and correct position counter errors. The evaluator automatically identifies deviations from the reference curve and adjusts the position status without external intervention or mechanical re-initialization, allowing the system to maintain itself during regular use.
3Device complexity
If a single Hall sensor is used, then system cost is reduced, but position accuracy deteriorates
Solution Approach 1:
The invention replaces the single Hall sensor's limited position determination capability with a force-based measurement system. By measuring the electrical current required to move the window and comparing it to the reference force-displacement curve, the system achieves accurate position determination electrically, compensating for the reduced sensor capability with a more informative measurement approach.
Solution Approach 2:
The system changes the measurement parameter from direct position sensing (Hall sensor output) to force sensing (current measurement). By measuring a different physical parameter (force/displacement relationship) and using it to infer position through comparison with the reference curve, the system achieves accurate position determination with a single sensor rather than requiring multiple position sensors.
4Device complexity
If position determination is performed by counting commutator current ripple, then system cost is reduced, but position accuracy deteriorates
Solution Approach 1:
The invention replaces the commutator current ripple counting method with direct force measurement through current sensing during window movement. Instead of indirectly inferring position from motor commutation characteristics, the system directly measures the force required to move the window and compares it to the reference force-displacement curve, providing more accurate position determination with similar system complexity.
Solution Approach 2:
The system changes the measurement parameter from motor commutation characteristics (indirect position indicator) to direct force measurement (direct position indicator). By measuring the actual force required to move the window and comparing it to the reference curve, the system obtains more reliable position information than indirect commutation-based methods, improving accuracy while maintaining cost-effectiveness.
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 approach enables precise position determination with reduced system costs, eliminating inaccuracies and mechanical loading, and is applicable to both window-lifters and sliding roofs, regardless of the pulse counting method used.
Implementation Method 1
a first-time initialization is implemented during production by running the window up to its upper mechanical stop. This is detected by a control unit and used as reference for later position counting processes. These position counting processes take place during the up and down movement of the window by counting the Hall sensor pulses related to the rotation of the respective drive motor.
Data Source
AI summary
In a method and a device for increasing the precision of the position determination of a motor-driven closure element of a vehicle, the data corresponding to a force-displacement reference curve and the data corresponding to a force-displacement actual value curve are used, a correlation function is calculated, the maximum thereof is found, and the counter status of a position counter is corrected by using the position offset associated with the determined maximum.