Power Window Pinching Detection Using Dynamic Thresholds
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Solution Overview
Problem
Conventional power window systems face challenges in accurately detecting pinching of objects due to constant threshold values in divided moving regions, leading to erroneous detections and failure to reliably detect pinching, especially in varying load conditions and environmental changes.
Innovation Solution
An opening and closing member control system that includes a drive mechanism, speed sensing means for measuring movement speed, and pinching sensing means which prestores learning data on speed changes during closing operations to compare current speed changes and determine pinching based on dynamic threshold values, reducing erroneous detections and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low threshold value is set to reliably detect pinching, then pinching detection reliability is improved, but erroneous detection increases
Solution Approach 1:
The patent applies dynamics by transitioning from static constant threshold values to dynamic learned threshold values. The system continuously learns the normal load characteristics during window operation and dynamically adjusts the threshold based on the difference between actual load and learned load, enabling reliable pinching detection while adapting to varying operating conditions and minimizing erroneous detections.
Solution Approach 2:
The patent implements feedback by using the learned load characteristics from normal operation to continuously refine pinching detection. The system feeds back the difference between actual load and learned load to dynamically adjust the detection threshold, creating a self-adapting detection mechanism that improves reliability without increasing erroneous detections.
2Device complexity
If constant threshold values are used in divided moving regions, then device complexity is reduced, but detection accuracy deteriorates due to load variations and environmental changes
Solution Approach 1:
The patent applies preliminary action by pre-learning the normal load characteristics during window operation before actual pinching detection begins. The system accumulates load data during normal operation and establishes learned threshold values in advance, creating a baseline for accurate pinching detection that adapts to specific operating conditions without increasing device complexity.
Solution Approach 2:
The patent implements parameter changes by transitioning from fixed constant threshold values to dynamically adjusted threshold values based on learned load characteristics. The system changes the detection parameter (threshold) according to actual operating conditions, enabling accurate pinching detection across varying loads and environmental conditions while maintaining simple device architecture.
3Quantity of substance
If the moving range is divided into multiple regions with standard medium values, then memory capacity requirement is reduced, but detection reliability deteriorates at region boundaries
Solution Approach 1:
The patent applies parameter changes by replacing the piecewise constant threshold approach with a continuous dynamic threshold based on learned load characteristics. Instead of using discrete standard medium values in divided regions, the system dynamically adjusts the threshold parameter based on the actual learned load at any position, eliminating boundary effects and improving reliability while maintaining low memory requirements.
Data Source
AI summary
An opening and closing member control system includes a rotation sensing device, which outputs a pulse signal synchronously to a movement of a window glass, and a controller, which senses pinching of an object by an opening and closing member based on the pulse signal. The controller has leaning stored data Δωm based on the pulse signal. The controller computes a rotational speed difference Δω at a current position of the window glass based on the pulse signal while the window glass is driven in a closing direction. The controller computes a difference between the rotational speed difference Δω and leaning stored data Δωm in such a manner that the controller determines whether the pinching of the object based on a comparison between the difference and a pinching determining threshold value β.